Version:  2.0.40 2.2.26 2.4.37 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8

Linux/drivers/tty/serial/msm_serial.c

  1 /*
  2  * Driver for msm7k serial device and console
  3  *
  4  * Copyright (C) 2007 Google, Inc.
  5  * Author: Robert Love <rlove@google.com>
  6  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  7  *
  8  * This software is licensed under the terms of the GNU General Public
  9  * License version 2, as published by the Free Software Foundation, and
 10  * may be copied, distributed, and modified under those terms.
 11  *
 12  * This program is distributed in the hope that it will be useful,
 13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 15  * GNU General Public License for more details.
 16  */
 17 
 18 #if defined(CONFIG_SERIAL_MSM_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
 19 # define SUPPORT_SYSRQ
 20 #endif
 21 
 22 #include <linux/kernel.h>
 23 #include <linux/atomic.h>
 24 #include <linux/dma-mapping.h>
 25 #include <linux/dmaengine.h>
 26 #include <linux/module.h>
 27 #include <linux/io.h>
 28 #include <linux/ioport.h>
 29 #include <linux/interrupt.h>
 30 #include <linux/init.h>
 31 #include <linux/console.h>
 32 #include <linux/tty.h>
 33 #include <linux/tty_flip.h>
 34 #include <linux/serial_core.h>
 35 #include <linux/slab.h>
 36 #include <linux/clk.h>
 37 #include <linux/platform_device.h>
 38 #include <linux/delay.h>
 39 #include <linux/of.h>
 40 #include <linux/of_device.h>
 41 #include <linux/wait.h>
 42 
 43 #define UART_MR1                        0x0000
 44 
 45 #define UART_MR1_AUTO_RFR_LEVEL0        0x3F
 46 #define UART_MR1_AUTO_RFR_LEVEL1        0x3FF00
 47 #define UART_DM_MR1_AUTO_RFR_LEVEL1     0xFFFFFF00
 48 #define UART_MR1_RX_RDY_CTL             BIT(7)
 49 #define UART_MR1_CTS_CTL                BIT(6)
 50 
 51 #define UART_MR2                        0x0004
 52 #define UART_MR2_ERROR_MODE             BIT(6)
 53 #define UART_MR2_BITS_PER_CHAR          0x30
 54 #define UART_MR2_BITS_PER_CHAR_5        (0x0 << 4)
 55 #define UART_MR2_BITS_PER_CHAR_6        (0x1 << 4)
 56 #define UART_MR2_BITS_PER_CHAR_7        (0x2 << 4)
 57 #define UART_MR2_BITS_PER_CHAR_8        (0x3 << 4)
 58 #define UART_MR2_STOP_BIT_LEN_ONE       (0x1 << 2)
 59 #define UART_MR2_STOP_BIT_LEN_TWO       (0x3 << 2)
 60 #define UART_MR2_PARITY_MODE_NONE       0x0
 61 #define UART_MR2_PARITY_MODE_ODD        0x1
 62 #define UART_MR2_PARITY_MODE_EVEN       0x2
 63 #define UART_MR2_PARITY_MODE_SPACE      0x3
 64 #define UART_MR2_PARITY_MODE            0x3
 65 
 66 #define UART_CSR                        0x0008
 67 
 68 #define UART_TF                         0x000C
 69 #define UARTDM_TF                       0x0070
 70 
 71 #define UART_CR                         0x0010
 72 #define UART_CR_CMD_NULL                (0 << 4)
 73 #define UART_CR_CMD_RESET_RX            (1 << 4)
 74 #define UART_CR_CMD_RESET_TX            (2 << 4)
 75 #define UART_CR_CMD_RESET_ERR           (3 << 4)
 76 #define UART_CR_CMD_RESET_BREAK_INT     (4 << 4)
 77 #define UART_CR_CMD_START_BREAK         (5 << 4)
 78 #define UART_CR_CMD_STOP_BREAK          (6 << 4)
 79 #define UART_CR_CMD_RESET_CTS           (7 << 4)
 80 #define UART_CR_CMD_RESET_STALE_INT     (8 << 4)
 81 #define UART_CR_CMD_PACKET_MODE         (9 << 4)
 82 #define UART_CR_CMD_MODE_RESET          (12 << 4)
 83 #define UART_CR_CMD_SET_RFR             (13 << 4)
 84 #define UART_CR_CMD_RESET_RFR           (14 << 4)
 85 #define UART_CR_CMD_PROTECTION_EN       (16 << 4)
 86 #define UART_CR_CMD_STALE_EVENT_DISABLE (6 << 8)
 87 #define UART_CR_CMD_STALE_EVENT_ENABLE  (80 << 4)
 88 #define UART_CR_CMD_FORCE_STALE         (4 << 8)
 89 #define UART_CR_CMD_RESET_TX_READY      (3 << 8)
 90 #define UART_CR_TX_DISABLE              BIT(3)
 91 #define UART_CR_TX_ENABLE               BIT(2)
 92 #define UART_CR_RX_DISABLE              BIT(1)
 93 #define UART_CR_RX_ENABLE               BIT(0)
 94 #define UART_CR_CMD_RESET_RXBREAK_START ((1 << 11) | (2 << 4))
 95 
 96 #define UART_IMR                        0x0014
 97 #define UART_IMR_TXLEV                  BIT(0)
 98 #define UART_IMR_RXSTALE                BIT(3)
 99 #define UART_IMR_RXLEV                  BIT(4)
100 #define UART_IMR_DELTA_CTS              BIT(5)
101 #define UART_IMR_CURRENT_CTS            BIT(6)
102 #define UART_IMR_RXBREAK_START          BIT(10)
103 
104 #define UART_IPR_RXSTALE_LAST           0x20
105 #define UART_IPR_STALE_LSB              0x1F
106 #define UART_IPR_STALE_TIMEOUT_MSB      0x3FF80
107 #define UART_DM_IPR_STALE_TIMEOUT_MSB   0xFFFFFF80
108 
109 #define UART_IPR                        0x0018
110 #define UART_TFWR                       0x001C
111 #define UART_RFWR                       0x0020
112 #define UART_HCR                        0x0024
113 
114 #define UART_MREG                       0x0028
115 #define UART_NREG                       0x002C
116 #define UART_DREG                       0x0030
117 #define UART_MNDREG                     0x0034
118 #define UART_IRDA                       0x0038
119 #define UART_MISR_MODE                  0x0040
120 #define UART_MISR_RESET                 0x0044
121 #define UART_MISR_EXPORT                0x0048
122 #define UART_MISR_VAL                   0x004C
123 #define UART_TEST_CTRL                  0x0050
124 
125 #define UART_SR                         0x0008
126 #define UART_SR_HUNT_CHAR               BIT(7)
127 #define UART_SR_RX_BREAK                BIT(6)
128 #define UART_SR_PAR_FRAME_ERR           BIT(5)
129 #define UART_SR_OVERRUN                 BIT(4)
130 #define UART_SR_TX_EMPTY                BIT(3)
131 #define UART_SR_TX_READY                BIT(2)
132 #define UART_SR_RX_FULL                 BIT(1)
133 #define UART_SR_RX_READY                BIT(0)
134 
135 #define UART_RF                         0x000C
136 #define UARTDM_RF                       0x0070
137 #define UART_MISR                       0x0010
138 #define UART_ISR                        0x0014
139 #define UART_ISR_TX_READY               BIT(7)
140 
141 #define UARTDM_RXFS                     0x50
142 #define UARTDM_RXFS_BUF_SHIFT           0x7
143 #define UARTDM_RXFS_BUF_MASK            0x7
144 
145 #define UARTDM_DMEN                     0x3C
146 #define UARTDM_DMEN_RX_SC_ENABLE        BIT(5)
147 #define UARTDM_DMEN_TX_SC_ENABLE        BIT(4)
148 
149 #define UARTDM_DMEN_TX_BAM_ENABLE       BIT(2)  /* UARTDM_1P4 */
150 #define UARTDM_DMEN_TX_DM_ENABLE        BIT(0)  /* < UARTDM_1P4 */
151 
152 #define UARTDM_DMEN_RX_BAM_ENABLE       BIT(3)  /* UARTDM_1P4 */
153 #define UARTDM_DMEN_RX_DM_ENABLE        BIT(1)  /* < UARTDM_1P4 */
154 
155 #define UARTDM_DMRX                     0x34
156 #define UARTDM_NCF_TX                   0x40
157 #define UARTDM_RX_TOTAL_SNAP            0x38
158 
159 #define UARTDM_BURST_SIZE               16   /* in bytes */
160 #define UARTDM_TX_AIGN(x)               ((x) & ~0x3) /* valid for > 1p3 */
161 #define UARTDM_TX_MAX                   256   /* in bytes, valid for <= 1p3 */
162 #define UARTDM_RX_SIZE                  (UART_XMIT_SIZE / 4)
163 
164 enum {
165         UARTDM_1P1 = 1,
166         UARTDM_1P2,
167         UARTDM_1P3,
168         UARTDM_1P4,
169 };
170 
171 struct msm_dma {
172         struct dma_chan         *chan;
173         enum dma_data_direction dir;
174         dma_addr_t              phys;
175         unsigned char           *virt;
176         dma_cookie_t            cookie;
177         u32                     enable_bit;
178         unsigned int            count;
179         struct dma_async_tx_descriptor  *desc;
180 };
181 
182 struct msm_port {
183         struct uart_port        uart;
184         char                    name[16];
185         struct clk              *clk;
186         struct clk              *pclk;
187         unsigned int            imr;
188         int                     is_uartdm;
189         unsigned int            old_snap_state;
190         bool                    break_detected;
191         struct msm_dma          tx_dma;
192         struct msm_dma          rx_dma;
193 };
194 
195 #define UART_TO_MSM(uart_port)  container_of(uart_port, struct msm_port, uart)
196 
197 static
198 void msm_write(struct uart_port *port, unsigned int val, unsigned int off)
199 {
200         writel_relaxed(val, port->membase + off);
201 }
202 
203 static
204 unsigned int msm_read(struct uart_port *port, unsigned int off)
205 {
206         return readl_relaxed(port->membase + off);
207 }
208 
209 /*
210  * Setup the MND registers to use the TCXO clock.
211  */
212 static void msm_serial_set_mnd_regs_tcxo(struct uart_port *port)
213 {
214         msm_write(port, 0x06, UART_MREG);
215         msm_write(port, 0xF1, UART_NREG);
216         msm_write(port, 0x0F, UART_DREG);
217         msm_write(port, 0x1A, UART_MNDREG);
218         port->uartclk = 1843200;
219 }
220 
221 /*
222  * Setup the MND registers to use the TCXO clock divided by 4.
223  */
224 static void msm_serial_set_mnd_regs_tcxoby4(struct uart_port *port)
225 {
226         msm_write(port, 0x18, UART_MREG);
227         msm_write(port, 0xF6, UART_NREG);
228         msm_write(port, 0x0F, UART_DREG);
229         msm_write(port, 0x0A, UART_MNDREG);
230         port->uartclk = 1843200;
231 }
232 
233 static void msm_serial_set_mnd_regs(struct uart_port *port)
234 {
235         struct msm_port *msm_port = UART_TO_MSM(port);
236 
237         /*
238          * These registers don't exist so we change the clk input rate
239          * on uartdm hardware instead
240          */
241         if (msm_port->is_uartdm)
242                 return;
243 
244         if (port->uartclk == 19200000)
245                 msm_serial_set_mnd_regs_tcxo(port);
246         else if (port->uartclk == 4800000)
247                 msm_serial_set_mnd_regs_tcxoby4(port);
248 }
249 
250 static void msm_handle_tx(struct uart_port *port);
251 static void msm_start_rx_dma(struct msm_port *msm_port);
252 
253 static void msm_stop_dma(struct uart_port *port, struct msm_dma *dma)
254 {
255         struct device *dev = port->dev;
256         unsigned int mapped;
257         u32 val;
258 
259         mapped = dma->count;
260         dma->count = 0;
261 
262         dmaengine_terminate_all(dma->chan);
263 
264         /*
265          * DMA Stall happens if enqueue and flush command happens concurrently.
266          * For example before changing the baud rate/protocol configuration and
267          * sending flush command to ADM, disable the channel of UARTDM.
268          * Note: should not reset the receiver here immediately as it is not
269          * suggested to do disable/reset or reset/disable at the same time.
270          */
271         val = msm_read(port, UARTDM_DMEN);
272         val &= ~dma->enable_bit;
273         msm_write(port, val, UARTDM_DMEN);
274 
275         if (mapped)
276                 dma_unmap_single(dev, dma->phys, mapped, dma->dir);
277 }
278 
279 static void msm_release_dma(struct msm_port *msm_port)
280 {
281         struct msm_dma *dma;
282 
283         dma = &msm_port->tx_dma;
284         if (dma->chan) {
285                 msm_stop_dma(&msm_port->uart, dma);
286                 dma_release_channel(dma->chan);
287         }
288 
289         memset(dma, 0, sizeof(*dma));
290 
291         dma = &msm_port->rx_dma;
292         if (dma->chan) {
293                 msm_stop_dma(&msm_port->uart, dma);
294                 dma_release_channel(dma->chan);
295                 kfree(dma->virt);
296         }
297 
298         memset(dma, 0, sizeof(*dma));
299 }
300 
301 static void msm_request_tx_dma(struct msm_port *msm_port, resource_size_t base)
302 {
303         struct device *dev = msm_port->uart.dev;
304         struct dma_slave_config conf;
305         struct msm_dma *dma;
306         u32 crci = 0;
307         int ret;
308 
309         dma = &msm_port->tx_dma;
310 
311         /* allocate DMA resources, if available */
312         dma->chan = dma_request_slave_channel_reason(dev, "tx");
313         if (IS_ERR(dma->chan))
314                 goto no_tx;
315 
316         of_property_read_u32(dev->of_node, "qcom,tx-crci", &crci);
317 
318         memset(&conf, 0, sizeof(conf));
319         conf.direction = DMA_MEM_TO_DEV;
320         conf.device_fc = true;
321         conf.dst_addr = base + UARTDM_TF;
322         conf.dst_maxburst = UARTDM_BURST_SIZE;
323         conf.slave_id = crci;
324 
325         ret = dmaengine_slave_config(dma->chan, &conf);
326         if (ret)
327                 goto rel_tx;
328 
329         dma->dir = DMA_TO_DEVICE;
330 
331         if (msm_port->is_uartdm < UARTDM_1P4)
332                 dma->enable_bit = UARTDM_DMEN_TX_DM_ENABLE;
333         else
334                 dma->enable_bit = UARTDM_DMEN_TX_BAM_ENABLE;
335 
336         return;
337 
338 rel_tx:
339         dma_release_channel(dma->chan);
340 no_tx:
341         memset(dma, 0, sizeof(*dma));
342 }
343 
344 static void msm_request_rx_dma(struct msm_port *msm_port, resource_size_t base)
345 {
346         struct device *dev = msm_port->uart.dev;
347         struct dma_slave_config conf;
348         struct msm_dma *dma;
349         u32 crci = 0;
350         int ret;
351 
352         dma = &msm_port->rx_dma;
353 
354         /* allocate DMA resources, if available */
355         dma->chan = dma_request_slave_channel_reason(dev, "rx");
356         if (IS_ERR(dma->chan))
357                 goto no_rx;
358 
359         of_property_read_u32(dev->of_node, "qcom,rx-crci", &crci);
360 
361         dma->virt = kzalloc(UARTDM_RX_SIZE, GFP_KERNEL);
362         if (!dma->virt)
363                 goto rel_rx;
364 
365         memset(&conf, 0, sizeof(conf));
366         conf.direction = DMA_DEV_TO_MEM;
367         conf.device_fc = true;
368         conf.src_addr = base + UARTDM_RF;
369         conf.src_maxburst = UARTDM_BURST_SIZE;
370         conf.slave_id = crci;
371 
372         ret = dmaengine_slave_config(dma->chan, &conf);
373         if (ret)
374                 goto err;
375 
376         dma->dir = DMA_FROM_DEVICE;
377 
378         if (msm_port->is_uartdm < UARTDM_1P4)
379                 dma->enable_bit = UARTDM_DMEN_RX_DM_ENABLE;
380         else
381                 dma->enable_bit = UARTDM_DMEN_RX_BAM_ENABLE;
382 
383         return;
384 err:
385         kfree(dma->virt);
386 rel_rx:
387         dma_release_channel(dma->chan);
388 no_rx:
389         memset(dma, 0, sizeof(*dma));
390 }
391 
392 static inline void msm_wait_for_xmitr(struct uart_port *port)
393 {
394         while (!(msm_read(port, UART_SR) & UART_SR_TX_EMPTY)) {
395                 if (msm_read(port, UART_ISR) & UART_ISR_TX_READY)
396                         break;
397                 udelay(1);
398         }
399         msm_write(port, UART_CR_CMD_RESET_TX_READY, UART_CR);
400 }
401 
402 static void msm_stop_tx(struct uart_port *port)
403 {
404         struct msm_port *msm_port = UART_TO_MSM(port);
405 
406         msm_port->imr &= ~UART_IMR_TXLEV;
407         msm_write(port, msm_port->imr, UART_IMR);
408 }
409 
410 static void msm_start_tx(struct uart_port *port)
411 {
412         struct msm_port *msm_port = UART_TO_MSM(port);
413         struct msm_dma *dma = &msm_port->tx_dma;
414 
415         /* Already started in DMA mode */
416         if (dma->count)
417                 return;
418 
419         msm_port->imr |= UART_IMR_TXLEV;
420         msm_write(port, msm_port->imr, UART_IMR);
421 }
422 
423 static void msm_reset_dm_count(struct uart_port *port, int count)
424 {
425         msm_wait_for_xmitr(port);
426         msm_write(port, count, UARTDM_NCF_TX);
427         msm_read(port, UARTDM_NCF_TX);
428 }
429 
430 static void msm_complete_tx_dma(void *args)
431 {
432         struct msm_port *msm_port = args;
433         struct uart_port *port = &msm_port->uart;
434         struct circ_buf *xmit = &port->state->xmit;
435         struct msm_dma *dma = &msm_port->tx_dma;
436         struct dma_tx_state state;
437         enum dma_status status;
438         unsigned long flags;
439         unsigned int count;
440         u32 val;
441 
442         spin_lock_irqsave(&port->lock, flags);
443 
444         /* Already stopped */
445         if (!dma->count)
446                 goto done;
447 
448         status = dmaengine_tx_status(dma->chan, dma->cookie, &state);
449 
450         dma_unmap_single(port->dev, dma->phys, dma->count, dma->dir);
451 
452         val = msm_read(port, UARTDM_DMEN);
453         val &= ~dma->enable_bit;
454         msm_write(port, val, UARTDM_DMEN);
455 
456         if (msm_port->is_uartdm > UARTDM_1P3) {
457                 msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
458                 msm_write(port, UART_CR_TX_ENABLE, UART_CR);
459         }
460 
461         count = dma->count - state.residue;
462         port->icount.tx += count;
463         dma->count = 0;
464 
465         xmit->tail += count;
466         xmit->tail &= UART_XMIT_SIZE - 1;
467 
468         /* Restore "Tx FIFO below watermark" interrupt */
469         msm_port->imr |= UART_IMR_TXLEV;
470         msm_write(port, msm_port->imr, UART_IMR);
471 
472         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
473                 uart_write_wakeup(port);
474 
475         msm_handle_tx(port);
476 done:
477         spin_unlock_irqrestore(&port->lock, flags);
478 }
479 
480 static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count)
481 {
482         struct circ_buf *xmit = &msm_port->uart.state->xmit;
483         struct uart_port *port = &msm_port->uart;
484         struct msm_dma *dma = &msm_port->tx_dma;
485         void *cpu_addr;
486         int ret;
487         u32 val;
488 
489         cpu_addr = &xmit->buf[xmit->tail];
490 
491         dma->phys = dma_map_single(port->dev, cpu_addr, count, dma->dir);
492         ret = dma_mapping_error(port->dev, dma->phys);
493         if (ret)
494                 return ret;
495 
496         dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
497                                                 count, DMA_MEM_TO_DEV,
498                                                 DMA_PREP_INTERRUPT |
499                                                 DMA_PREP_FENCE);
500         if (!dma->desc) {
501                 ret = -EIO;
502                 goto unmap;
503         }
504 
505         dma->desc->callback = msm_complete_tx_dma;
506         dma->desc->callback_param = msm_port;
507 
508         dma->cookie = dmaengine_submit(dma->desc);
509         ret = dma_submit_error(dma->cookie);
510         if (ret)
511                 goto unmap;
512 
513         /*
514          * Using DMA complete for Tx FIFO reload, no need for
515          * "Tx FIFO below watermark" one, disable it
516          */
517         msm_port->imr &= ~UART_IMR_TXLEV;
518         msm_write(port, msm_port->imr, UART_IMR);
519 
520         dma->count = count;
521 
522         val = msm_read(port, UARTDM_DMEN);
523         val |= dma->enable_bit;
524 
525         if (msm_port->is_uartdm < UARTDM_1P4)
526                 msm_write(port, val, UARTDM_DMEN);
527 
528         msm_reset_dm_count(port, count);
529 
530         if (msm_port->is_uartdm > UARTDM_1P3)
531                 msm_write(port, val, UARTDM_DMEN);
532 
533         dma_async_issue_pending(dma->chan);
534         return 0;
535 unmap:
536         dma_unmap_single(port->dev, dma->phys, count, dma->dir);
537         return ret;
538 }
539 
540 static void msm_complete_rx_dma(void *args)
541 {
542         struct msm_port *msm_port = args;
543         struct uart_port *port = &msm_port->uart;
544         struct tty_port *tport = &port->state->port;
545         struct msm_dma *dma = &msm_port->rx_dma;
546         int count = 0, i, sysrq;
547         unsigned long flags;
548         u32 val;
549 
550         spin_lock_irqsave(&port->lock, flags);
551 
552         /* Already stopped */
553         if (!dma->count)
554                 goto done;
555 
556         val = msm_read(port, UARTDM_DMEN);
557         val &= ~dma->enable_bit;
558         msm_write(port, val, UARTDM_DMEN);
559 
560         if (msm_read(port, UART_SR) & UART_SR_OVERRUN) {
561                 port->icount.overrun++;
562                 tty_insert_flip_char(tport, 0, TTY_OVERRUN);
563                 msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
564         }
565 
566         count = msm_read(port, UARTDM_RX_TOTAL_SNAP);
567 
568         port->icount.rx += count;
569 
570         dma->count = 0;
571 
572         dma_unmap_single(port->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
573 
574         for (i = 0; i < count; i++) {
575                 char flag = TTY_NORMAL;
576 
577                 if (msm_port->break_detected && dma->virt[i] == 0) {
578                         port->icount.brk++;
579                         flag = TTY_BREAK;
580                         msm_port->break_detected = false;
581                         if (uart_handle_break(port))
582                                 continue;
583                 }
584 
585                 if (!(port->read_status_mask & UART_SR_RX_BREAK))
586                         flag = TTY_NORMAL;
587 
588                 spin_unlock_irqrestore(&port->lock, flags);
589                 sysrq = uart_handle_sysrq_char(port, dma->virt[i]);
590                 spin_lock_irqsave(&port->lock, flags);
591                 if (!sysrq)
592                         tty_insert_flip_char(tport, dma->virt[i], flag);
593         }
594 
595         msm_start_rx_dma(msm_port);
596 done:
597         spin_unlock_irqrestore(&port->lock, flags);
598 
599         if (count)
600                 tty_flip_buffer_push(tport);
601 }
602 
603 static void msm_start_rx_dma(struct msm_port *msm_port)
604 {
605         struct msm_dma *dma = &msm_port->rx_dma;
606         struct uart_port *uart = &msm_port->uart;
607         u32 val;
608         int ret;
609 
610         if (!dma->chan)
611                 return;
612 
613         dma->phys = dma_map_single(uart->dev, dma->virt,
614                                    UARTDM_RX_SIZE, dma->dir);
615         ret = dma_mapping_error(uart->dev, dma->phys);
616         if (ret)
617                 return;
618 
619         dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
620                                                 UARTDM_RX_SIZE, DMA_DEV_TO_MEM,
621                                                 DMA_PREP_INTERRUPT);
622         if (!dma->desc)
623                 goto unmap;
624 
625         dma->desc->callback = msm_complete_rx_dma;
626         dma->desc->callback_param = msm_port;
627 
628         dma->cookie = dmaengine_submit(dma->desc);
629         ret = dma_submit_error(dma->cookie);
630         if (ret)
631                 goto unmap;
632         /*
633          * Using DMA for FIFO off-load, no need for "Rx FIFO over
634          * watermark" or "stale" interrupts, disable them
635          */
636         msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
637 
638         /*
639          * Well, when DMA is ADM3 engine(implied by <= UARTDM v1.3),
640          * we need RXSTALE to flush input DMA fifo to memory
641          */
642         if (msm_port->is_uartdm < UARTDM_1P4)
643                 msm_port->imr |= UART_IMR_RXSTALE;
644 
645         msm_write(uart, msm_port->imr, UART_IMR);
646 
647         dma->count = UARTDM_RX_SIZE;
648 
649         dma_async_issue_pending(dma->chan);
650 
651         msm_write(uart, UART_CR_CMD_RESET_STALE_INT, UART_CR);
652         msm_write(uart, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
653 
654         val = msm_read(uart, UARTDM_DMEN);
655         val |= dma->enable_bit;
656 
657         if (msm_port->is_uartdm < UARTDM_1P4)
658                 msm_write(uart, val, UARTDM_DMEN);
659 
660         msm_write(uart, UARTDM_RX_SIZE, UARTDM_DMRX);
661 
662         if (msm_port->is_uartdm > UARTDM_1P3)
663                 msm_write(uart, val, UARTDM_DMEN);
664 
665         return;
666 unmap:
667         dma_unmap_single(uart->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
668 }
669 
670 static void msm_stop_rx(struct uart_port *port)
671 {
672         struct msm_port *msm_port = UART_TO_MSM(port);
673         struct msm_dma *dma = &msm_port->rx_dma;
674 
675         msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
676         msm_write(port, msm_port->imr, UART_IMR);
677 
678         if (dma->chan)
679                 msm_stop_dma(port, dma);
680 }
681 
682 static void msm_enable_ms(struct uart_port *port)
683 {
684         struct msm_port *msm_port = UART_TO_MSM(port);
685 
686         msm_port->imr |= UART_IMR_DELTA_CTS;
687         msm_write(port, msm_port->imr, UART_IMR);
688 }
689 
690 static void msm_handle_rx_dm(struct uart_port *port, unsigned int misr)
691 {
692         struct tty_port *tport = &port->state->port;
693         unsigned int sr;
694         int count = 0;
695         struct msm_port *msm_port = UART_TO_MSM(port);
696 
697         if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
698                 port->icount.overrun++;
699                 tty_insert_flip_char(tport, 0, TTY_OVERRUN);
700                 msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
701         }
702 
703         if (misr & UART_IMR_RXSTALE) {
704                 count = msm_read(port, UARTDM_RX_TOTAL_SNAP) -
705                         msm_port->old_snap_state;
706                 msm_port->old_snap_state = 0;
707         } else {
708                 count = 4 * (msm_read(port, UART_RFWR));
709                 msm_port->old_snap_state += count;
710         }
711 
712         /* TODO: Precise error reporting */
713 
714         port->icount.rx += count;
715 
716         while (count > 0) {
717                 unsigned char buf[4];
718                 int sysrq, r_count, i;
719 
720                 sr = msm_read(port, UART_SR);
721                 if ((sr & UART_SR_RX_READY) == 0) {
722                         msm_port->old_snap_state -= count;
723                         break;
724                 }
725 
726                 ioread32_rep(port->membase + UARTDM_RF, buf, 1);
727                 r_count = min_t(int, count, sizeof(buf));
728 
729                 for (i = 0; i < r_count; i++) {
730                         char flag = TTY_NORMAL;
731 
732                         if (msm_port->break_detected && buf[i] == 0) {
733                                 port->icount.brk++;
734                                 flag = TTY_BREAK;
735                                 msm_port->break_detected = false;
736                                 if (uart_handle_break(port))
737                                         continue;
738                         }
739 
740                         if (!(port->read_status_mask & UART_SR_RX_BREAK))
741                                 flag = TTY_NORMAL;
742 
743                         spin_unlock(&port->lock);
744                         sysrq = uart_handle_sysrq_char(port, buf[i]);
745                         spin_lock(&port->lock);
746                         if (!sysrq)
747                                 tty_insert_flip_char(tport, buf[i], flag);
748                 }
749                 count -= r_count;
750         }
751 
752         spin_unlock(&port->lock);
753         tty_flip_buffer_push(tport);
754         spin_lock(&port->lock);
755 
756         if (misr & (UART_IMR_RXSTALE))
757                 msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
758         msm_write(port, 0xFFFFFF, UARTDM_DMRX);
759         msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
760 
761         /* Try to use DMA */
762         msm_start_rx_dma(msm_port);
763 }
764 
765 static void msm_handle_rx(struct uart_port *port)
766 {
767         struct tty_port *tport = &port->state->port;
768         unsigned int sr;
769 
770         /*
771          * Handle overrun. My understanding of the hardware is that overrun
772          * is not tied to the RX buffer, so we handle the case out of band.
773          */
774         if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
775                 port->icount.overrun++;
776                 tty_insert_flip_char(tport, 0, TTY_OVERRUN);
777                 msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
778         }
779 
780         /* and now the main RX loop */
781         while ((sr = msm_read(port, UART_SR)) & UART_SR_RX_READY) {
782                 unsigned int c;
783                 char flag = TTY_NORMAL;
784                 int sysrq;
785 
786                 c = msm_read(port, UART_RF);
787 
788                 if (sr & UART_SR_RX_BREAK) {
789                         port->icount.brk++;
790                         if (uart_handle_break(port))
791                                 continue;
792                 } else if (sr & UART_SR_PAR_FRAME_ERR) {
793                         port->icount.frame++;
794                 } else {
795                         port->icount.rx++;
796                 }
797 
798                 /* Mask conditions we're ignorning. */
799                 sr &= port->read_status_mask;
800 
801                 if (sr & UART_SR_RX_BREAK)
802                         flag = TTY_BREAK;
803                 else if (sr & UART_SR_PAR_FRAME_ERR)
804                         flag = TTY_FRAME;
805 
806                 spin_unlock(&port->lock);
807                 sysrq = uart_handle_sysrq_char(port, c);
808                 spin_lock(&port->lock);
809                 if (!sysrq)
810                         tty_insert_flip_char(tport, c, flag);
811         }
812 
813         spin_unlock(&port->lock);
814         tty_flip_buffer_push(tport);
815         spin_lock(&port->lock);
816 }
817 
818 static void msm_handle_tx_pio(struct uart_port *port, unsigned int tx_count)
819 {
820         struct circ_buf *xmit = &port->state->xmit;
821         struct msm_port *msm_port = UART_TO_MSM(port);
822         unsigned int num_chars;
823         unsigned int tf_pointer = 0;
824         void __iomem *tf;
825 
826         if (msm_port->is_uartdm)
827                 tf = port->membase + UARTDM_TF;
828         else
829                 tf = port->membase + UART_TF;
830 
831         if (tx_count && msm_port->is_uartdm)
832                 msm_reset_dm_count(port, tx_count);
833 
834         while (tf_pointer < tx_count) {
835                 int i;
836                 char buf[4] = { 0 };
837 
838                 if (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
839                         break;
840 
841                 if (msm_port->is_uartdm)
842                         num_chars = min(tx_count - tf_pointer,
843                                         (unsigned int)sizeof(buf));
844                 else
845                         num_chars = 1;
846 
847                 for (i = 0; i < num_chars; i++) {
848                         buf[i] = xmit->buf[xmit->tail + i];
849                         port->icount.tx++;
850                 }
851 
852                 iowrite32_rep(tf, buf, 1);
853                 xmit->tail = (xmit->tail + num_chars) & (UART_XMIT_SIZE - 1);
854                 tf_pointer += num_chars;
855         }
856 
857         /* disable tx interrupts if nothing more to send */
858         if (uart_circ_empty(xmit))
859                 msm_stop_tx(port);
860 
861         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
862                 uart_write_wakeup(port);
863 }
864 
865 static void msm_handle_tx(struct uart_port *port)
866 {
867         struct msm_port *msm_port = UART_TO_MSM(port);
868         struct circ_buf *xmit = &msm_port->uart.state->xmit;
869         struct msm_dma *dma = &msm_port->tx_dma;
870         unsigned int pio_count, dma_count, dma_min;
871         void __iomem *tf;
872         int err = 0;
873 
874         if (port->x_char) {
875                 if (msm_port->is_uartdm)
876                         tf = port->membase + UARTDM_TF;
877                 else
878                         tf = port->membase + UART_TF;
879 
880                 if (msm_port->is_uartdm)
881                         msm_reset_dm_count(port, 1);
882 
883                 iowrite8_rep(tf, &port->x_char, 1);
884                 port->icount.tx++;
885                 port->x_char = 0;
886                 return;
887         }
888 
889         if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
890                 msm_stop_tx(port);
891                 return;
892         }
893 
894         pio_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
895         dma_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
896 
897         dma_min = 1;    /* Always DMA */
898         if (msm_port->is_uartdm > UARTDM_1P3) {
899                 dma_count = UARTDM_TX_AIGN(dma_count);
900                 dma_min = UARTDM_BURST_SIZE;
901         } else {
902                 if (dma_count > UARTDM_TX_MAX)
903                         dma_count = UARTDM_TX_MAX;
904         }
905 
906         if (pio_count > port->fifosize)
907                 pio_count = port->fifosize;
908 
909         if (!dma->chan || dma_count < dma_min)
910                 msm_handle_tx_pio(port, pio_count);
911         else
912                 err = msm_handle_tx_dma(msm_port, dma_count);
913 
914         if (err)        /* fall back to PIO mode */
915                 msm_handle_tx_pio(port, pio_count);
916 }
917 
918 static void msm_handle_delta_cts(struct uart_port *port)
919 {
920         msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
921         port->icount.cts++;
922         wake_up_interruptible(&port->state->port.delta_msr_wait);
923 }
924 
925 static irqreturn_t msm_uart_irq(int irq, void *dev_id)
926 {
927         struct uart_port *port = dev_id;
928         struct msm_port *msm_port = UART_TO_MSM(port);
929         struct msm_dma *dma = &msm_port->rx_dma;
930         unsigned long flags;
931         unsigned int misr;
932         u32 val;
933 
934         spin_lock_irqsave(&port->lock, flags);
935         misr = msm_read(port, UART_MISR);
936         msm_write(port, 0, UART_IMR); /* disable interrupt */
937 
938         if (misr & UART_IMR_RXBREAK_START) {
939                 msm_port->break_detected = true;
940                 msm_write(port, UART_CR_CMD_RESET_RXBREAK_START, UART_CR);
941         }
942 
943         if (misr & (UART_IMR_RXLEV | UART_IMR_RXSTALE)) {
944                 if (dma->count) {
945                         val = UART_CR_CMD_STALE_EVENT_DISABLE;
946                         msm_write(port, val, UART_CR);
947                         val = UART_CR_CMD_RESET_STALE_INT;
948                         msm_write(port, val, UART_CR);
949                         /*
950                          * Flush DMA input fifo to memory, this will also
951                          * trigger DMA RX completion
952                          */
953                         dmaengine_terminate_all(dma->chan);
954                 } else if (msm_port->is_uartdm) {
955                         msm_handle_rx_dm(port, misr);
956                 } else {
957                         msm_handle_rx(port);
958                 }
959         }
960         if (misr & UART_IMR_TXLEV)
961                 msm_handle_tx(port);
962         if (misr & UART_IMR_DELTA_CTS)
963                 msm_handle_delta_cts(port);
964 
965         msm_write(port, msm_port->imr, UART_IMR); /* restore interrupt */
966         spin_unlock_irqrestore(&port->lock, flags);
967 
968         return IRQ_HANDLED;
969 }
970 
971 static unsigned int msm_tx_empty(struct uart_port *port)
972 {
973         return (msm_read(port, UART_SR) & UART_SR_TX_EMPTY) ? TIOCSER_TEMT : 0;
974 }
975 
976 static unsigned int msm_get_mctrl(struct uart_port *port)
977 {
978         return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR | TIOCM_RTS;
979 }
980 
981 static void msm_reset(struct uart_port *port)
982 {
983         struct msm_port *msm_port = UART_TO_MSM(port);
984 
985         /* reset everything */
986         msm_write(port, UART_CR_CMD_RESET_RX, UART_CR);
987         msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
988         msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
989         msm_write(port, UART_CR_CMD_RESET_BREAK_INT, UART_CR);
990         msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
991         msm_write(port, UART_CR_CMD_SET_RFR, UART_CR);
992 
993         /* Disable DM modes */
994         if (msm_port->is_uartdm)
995                 msm_write(port, 0, UARTDM_DMEN);
996 }
997 
998 static void msm_set_mctrl(struct uart_port *port, unsigned int mctrl)
999 {
1000         unsigned int mr;
1001 
1002         mr = msm_read(port, UART_MR1);
1003 
1004         if (!(mctrl & TIOCM_RTS)) {
1005                 mr &= ~UART_MR1_RX_RDY_CTL;
1006                 msm_write(port, mr, UART_MR1);
1007                 msm_write(port, UART_CR_CMD_RESET_RFR, UART_CR);
1008         } else {
1009                 mr |= UART_MR1_RX_RDY_CTL;
1010                 msm_write(port, mr, UART_MR1);
1011         }
1012 }
1013 
1014 static void msm_break_ctl(struct uart_port *port, int break_ctl)
1015 {
1016         if (break_ctl)
1017                 msm_write(port, UART_CR_CMD_START_BREAK, UART_CR);
1018         else
1019                 msm_write(port, UART_CR_CMD_STOP_BREAK, UART_CR);
1020 }
1021 
1022 struct msm_baud_map {
1023         u16     divisor;
1024         u8      code;
1025         u8      rxstale;
1026 };
1027 
1028 static const struct msm_baud_map *
1029 msm_find_best_baud(struct uart_port *port, unsigned int baud,
1030                    unsigned long *rate)
1031 {
1032         struct msm_port *msm_port = UART_TO_MSM(port);
1033         unsigned int divisor, result;
1034         unsigned long target, old, best_rate = 0, diff, best_diff = ULONG_MAX;
1035         const struct msm_baud_map *entry, *end, *best;
1036         static const struct msm_baud_map table[] = {
1037                 {    1, 0xff, 31 },
1038                 {    2, 0xee, 16 },
1039                 {    3, 0xdd,  8 },
1040                 {    4, 0xcc,  6 },
1041                 {    6, 0xbb,  6 },
1042                 {    8, 0xaa,  6 },
1043                 {   12, 0x99,  6 },
1044                 {   16, 0x88,  1 },
1045                 {   24, 0x77,  1 },
1046                 {   32, 0x66,  1 },
1047                 {   48, 0x55,  1 },
1048                 {   96, 0x44,  1 },
1049                 {  192, 0x33,  1 },
1050                 {  384, 0x22,  1 },
1051                 {  768, 0x11,  1 },
1052                 { 1536, 0x00,  1 },
1053         };
1054 
1055         best = table; /* Default to smallest divider */
1056         target = clk_round_rate(msm_port->clk, 16 * baud);
1057         divisor = DIV_ROUND_CLOSEST(target, 16 * baud);
1058 
1059         end = table + ARRAY_SIZE(table);
1060         entry = table;
1061         while (entry < end) {
1062                 if (entry->divisor <= divisor) {
1063                         result = target / entry->divisor / 16;
1064                         diff = abs(result - baud);
1065 
1066                         /* Keep track of best entry */
1067                         if (diff < best_diff) {
1068                                 best_diff = diff;
1069                                 best = entry;
1070                                 best_rate = target;
1071                         }
1072 
1073                         if (result == baud)
1074                                 break;
1075                 } else if (entry->divisor > divisor) {
1076                         old = target;
1077                         target = clk_round_rate(msm_port->clk, old + 1);
1078                         /*
1079                          * The rate didn't get any faster so we can't do
1080                          * better at dividing it down
1081                          */
1082                         if (target == old)
1083                                 break;
1084 
1085                         /* Start the divisor search over at this new rate */
1086                         entry = table;
1087                         divisor = DIV_ROUND_CLOSEST(target, 16 * baud);
1088                         continue;
1089                 }
1090                 entry++;
1091         }
1092 
1093         *rate = best_rate;
1094         return best;
1095 }
1096 
1097 static int msm_set_baud_rate(struct uart_port *port, unsigned int baud,
1098                              unsigned long *saved_flags)
1099 {
1100         unsigned int rxstale, watermark, mask;
1101         struct msm_port *msm_port = UART_TO_MSM(port);
1102         const struct msm_baud_map *entry;
1103         unsigned long flags, rate;
1104 
1105         flags = *saved_flags;
1106         spin_unlock_irqrestore(&port->lock, flags);
1107 
1108         entry = msm_find_best_baud(port, baud, &rate);
1109         clk_set_rate(msm_port->clk, rate);
1110         baud = rate / 16 / entry->divisor;
1111 
1112         spin_lock_irqsave(&port->lock, flags);
1113         *saved_flags = flags;
1114         port->uartclk = rate;
1115 
1116         msm_write(port, entry->code, UART_CSR);
1117 
1118         /* RX stale watermark */
1119         rxstale = entry->rxstale;
1120         watermark = UART_IPR_STALE_LSB & rxstale;
1121         if (msm_port->is_uartdm) {
1122                 mask = UART_DM_IPR_STALE_TIMEOUT_MSB;
1123         } else {
1124                 watermark |= UART_IPR_RXSTALE_LAST;
1125                 mask = UART_IPR_STALE_TIMEOUT_MSB;
1126         }
1127 
1128         watermark |= mask & (rxstale << 2);
1129 
1130         msm_write(port, watermark, UART_IPR);
1131 
1132         /* set RX watermark */
1133         watermark = (port->fifosize * 3) / 4;
1134         msm_write(port, watermark, UART_RFWR);
1135 
1136         /* set TX watermark */
1137         msm_write(port, 10, UART_TFWR);
1138 
1139         msm_write(port, UART_CR_CMD_PROTECTION_EN, UART_CR);
1140         msm_reset(port);
1141 
1142         /* Enable RX and TX */
1143         msm_write(port, UART_CR_TX_ENABLE | UART_CR_RX_ENABLE, UART_CR);
1144 
1145         /* turn on RX and CTS interrupts */
1146         msm_port->imr = UART_IMR_RXLEV | UART_IMR_RXSTALE |
1147                         UART_IMR_CURRENT_CTS | UART_IMR_RXBREAK_START;
1148 
1149         msm_write(port, msm_port->imr, UART_IMR);
1150 
1151         if (msm_port->is_uartdm) {
1152                 msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
1153                 msm_write(port, 0xFFFFFF, UARTDM_DMRX);
1154                 msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
1155         }
1156 
1157         return baud;
1158 }
1159 
1160 static void msm_init_clock(struct uart_port *port)
1161 {
1162         struct msm_port *msm_port = UART_TO_MSM(port);
1163 
1164         clk_prepare_enable(msm_port->clk);
1165         clk_prepare_enable(msm_port->pclk);
1166         msm_serial_set_mnd_regs(port);
1167 }
1168 
1169 static int msm_startup(struct uart_port *port)
1170 {
1171         struct msm_port *msm_port = UART_TO_MSM(port);
1172         unsigned int data, rfr_level, mask;
1173         int ret;
1174 
1175         snprintf(msm_port->name, sizeof(msm_port->name),
1176                  "msm_serial%d", port->line);
1177 
1178         ret = request_irq(port->irq, msm_uart_irq, IRQF_TRIGGER_HIGH,
1179                           msm_port->name, port);
1180         if (unlikely(ret))
1181                 return ret;
1182 
1183         msm_init_clock(port);
1184 
1185         if (likely(port->fifosize > 12))
1186                 rfr_level = port->fifosize - 12;
1187         else
1188                 rfr_level = port->fifosize;
1189 
1190         /* set automatic RFR level */
1191         data = msm_read(port, UART_MR1);
1192 
1193         if (msm_port->is_uartdm)
1194                 mask = UART_DM_MR1_AUTO_RFR_LEVEL1;
1195         else
1196                 mask = UART_MR1_AUTO_RFR_LEVEL1;
1197 
1198         data &= ~mask;
1199         data &= ~UART_MR1_AUTO_RFR_LEVEL0;
1200         data |= mask & (rfr_level << 2);
1201         data |= UART_MR1_AUTO_RFR_LEVEL0 & rfr_level;
1202         msm_write(port, data, UART_MR1);
1203 
1204         if (msm_port->is_uartdm) {
1205                 msm_request_tx_dma(msm_port, msm_port->uart.mapbase);
1206                 msm_request_rx_dma(msm_port, msm_port->uart.mapbase);
1207         }
1208 
1209         return 0;
1210 }
1211 
1212 static void msm_shutdown(struct uart_port *port)
1213 {
1214         struct msm_port *msm_port = UART_TO_MSM(port);
1215 
1216         msm_port->imr = 0;
1217         msm_write(port, 0, UART_IMR); /* disable interrupts */
1218 
1219         if (msm_port->is_uartdm)
1220                 msm_release_dma(msm_port);
1221 
1222         clk_disable_unprepare(msm_port->clk);
1223 
1224         free_irq(port->irq, port);
1225 }
1226 
1227 static void msm_set_termios(struct uart_port *port, struct ktermios *termios,
1228                             struct ktermios *old)
1229 {
1230         struct msm_port *msm_port = UART_TO_MSM(port);
1231         struct msm_dma *dma = &msm_port->rx_dma;
1232         unsigned long flags;
1233         unsigned int baud, mr;
1234 
1235         spin_lock_irqsave(&port->lock, flags);
1236 
1237         if (dma->chan) /* Terminate if any */
1238                 msm_stop_dma(port, dma);
1239 
1240         /* calculate and set baud rate */
1241         baud = uart_get_baud_rate(port, termios, old, 300, 4000000);
1242         baud = msm_set_baud_rate(port, baud, &flags);
1243         if (tty_termios_baud_rate(termios))
1244                 tty_termios_encode_baud_rate(termios, baud, baud);
1245 
1246         /* calculate parity */
1247         mr = msm_read(port, UART_MR2);
1248         mr &= ~UART_MR2_PARITY_MODE;
1249         if (termios->c_cflag & PARENB) {
1250                 if (termios->c_cflag & PARODD)
1251                         mr |= UART_MR2_PARITY_MODE_ODD;
1252                 else if (termios->c_cflag & CMSPAR)
1253                         mr |= UART_MR2_PARITY_MODE_SPACE;
1254                 else
1255                         mr |= UART_MR2_PARITY_MODE_EVEN;
1256         }
1257 
1258         /* calculate bits per char */
1259         mr &= ~UART_MR2_BITS_PER_CHAR;
1260         switch (termios->c_cflag & CSIZE) {
1261         case CS5:
1262                 mr |= UART_MR2_BITS_PER_CHAR_5;
1263                 break;
1264         case CS6:
1265                 mr |= UART_MR2_BITS_PER_CHAR_6;
1266                 break;
1267         case CS7:
1268                 mr |= UART_MR2_BITS_PER_CHAR_7;
1269                 break;
1270         case CS8:
1271         default:
1272                 mr |= UART_MR2_BITS_PER_CHAR_8;
1273                 break;
1274         }
1275 
1276         /* calculate stop bits */
1277         mr &= ~(UART_MR2_STOP_BIT_LEN_ONE | UART_MR2_STOP_BIT_LEN_TWO);
1278         if (termios->c_cflag & CSTOPB)
1279                 mr |= UART_MR2_STOP_BIT_LEN_TWO;
1280         else
1281                 mr |= UART_MR2_STOP_BIT_LEN_ONE;
1282 
1283         /* set parity, bits per char, and stop bit */
1284         msm_write(port, mr, UART_MR2);
1285 
1286         /* calculate and set hardware flow control */
1287         mr = msm_read(port, UART_MR1);
1288         mr &= ~(UART_MR1_CTS_CTL | UART_MR1_RX_RDY_CTL);
1289         if (termios->c_cflag & CRTSCTS) {
1290                 mr |= UART_MR1_CTS_CTL;
1291                 mr |= UART_MR1_RX_RDY_CTL;
1292         }
1293         msm_write(port, mr, UART_MR1);
1294 
1295         /* Configure status bits to ignore based on termio flags. */
1296         port->read_status_mask = 0;
1297         if (termios->c_iflag & INPCK)
1298                 port->read_status_mask |= UART_SR_PAR_FRAME_ERR;
1299         if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
1300                 port->read_status_mask |= UART_SR_RX_BREAK;
1301 
1302         uart_update_timeout(port, termios->c_cflag, baud);
1303 
1304         /* Try to use DMA */
1305         msm_start_rx_dma(msm_port);
1306 
1307         spin_unlock_irqrestore(&port->lock, flags);
1308 }
1309 
1310 static const char *msm_type(struct uart_port *port)
1311 {
1312         return "MSM";
1313 }
1314 
1315 static void msm_release_port(struct uart_port *port)
1316 {
1317         struct platform_device *pdev = to_platform_device(port->dev);
1318         struct resource *uart_resource;
1319         resource_size_t size;
1320 
1321         uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1322         if (unlikely(!uart_resource))
1323                 return;
1324         size = resource_size(uart_resource);
1325 
1326         release_mem_region(port->mapbase, size);
1327         iounmap(port->membase);
1328         port->membase = NULL;
1329 }
1330 
1331 static int msm_request_port(struct uart_port *port)
1332 {
1333         struct platform_device *pdev = to_platform_device(port->dev);
1334         struct resource *uart_resource;
1335         resource_size_t size;
1336         int ret;
1337 
1338         uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1339         if (unlikely(!uart_resource))
1340                 return -ENXIO;
1341 
1342         size = resource_size(uart_resource);
1343 
1344         if (!request_mem_region(port->mapbase, size, "msm_serial"))
1345                 return -EBUSY;
1346 
1347         port->membase = ioremap(port->mapbase, size);
1348         if (!port->membase) {
1349                 ret = -EBUSY;
1350                 goto fail_release_port;
1351         }
1352 
1353         return 0;
1354 
1355 fail_release_port:
1356         release_mem_region(port->mapbase, size);
1357         return ret;
1358 }
1359 
1360 static void msm_config_port(struct uart_port *port, int flags)
1361 {
1362         int ret;
1363 
1364         if (flags & UART_CONFIG_TYPE) {
1365                 port->type = PORT_MSM;
1366                 ret = msm_request_port(port);
1367                 if (ret)
1368                         return;
1369         }
1370 }
1371 
1372 static int msm_verify_port(struct uart_port *port, struct serial_struct *ser)
1373 {
1374         if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_MSM))
1375                 return -EINVAL;
1376         if (unlikely(port->irq != ser->irq))
1377                 return -EINVAL;
1378         return 0;
1379 }
1380 
1381 static void msm_power(struct uart_port *port, unsigned int state,
1382                       unsigned int oldstate)
1383 {
1384         struct msm_port *msm_port = UART_TO_MSM(port);
1385 
1386         switch (state) {
1387         case 0:
1388                 clk_prepare_enable(msm_port->clk);
1389                 clk_prepare_enable(msm_port->pclk);
1390                 break;
1391         case 3:
1392                 clk_disable_unprepare(msm_port->clk);
1393                 clk_disable_unprepare(msm_port->pclk);
1394                 break;
1395         default:
1396                 pr_err("msm_serial: Unknown PM state %d\n", state);
1397         }
1398 }
1399 
1400 #ifdef CONFIG_CONSOLE_POLL
1401 static int msm_poll_get_char_single(struct uart_port *port)
1402 {
1403         struct msm_port *msm_port = UART_TO_MSM(port);
1404         unsigned int rf_reg = msm_port->is_uartdm ? UARTDM_RF : UART_RF;
1405 
1406         if (!(msm_read(port, UART_SR) & UART_SR_RX_READY))
1407                 return NO_POLL_CHAR;
1408 
1409         return msm_read(port, rf_reg) & 0xff;
1410 }
1411 
1412 static int msm_poll_get_char_dm(struct uart_port *port)
1413 {
1414         int c;
1415         static u32 slop;
1416         static int count;
1417         unsigned char *sp = (unsigned char *)&slop;
1418 
1419         /* Check if a previous read had more than one char */
1420         if (count) {
1421                 c = sp[sizeof(slop) - count];
1422                 count--;
1423         /* Or if FIFO is empty */
1424         } else if (!(msm_read(port, UART_SR) & UART_SR_RX_READY)) {
1425                 /*
1426                  * If RX packing buffer has less than a word, force stale to
1427                  * push contents into RX FIFO
1428                  */
1429                 count = msm_read(port, UARTDM_RXFS);
1430                 count = (count >> UARTDM_RXFS_BUF_SHIFT) & UARTDM_RXFS_BUF_MASK;
1431                 if (count) {
1432                         msm_write(port, UART_CR_CMD_FORCE_STALE, UART_CR);
1433                         slop = msm_read(port, UARTDM_RF);
1434                         c = sp[0];
1435                         count--;
1436                         msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
1437                         msm_write(port, 0xFFFFFF, UARTDM_DMRX);
1438                         msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE,
1439                                   UART_CR);
1440                 } else {
1441                         c = NO_POLL_CHAR;
1442                 }
1443         /* FIFO has a word */
1444         } else {
1445                 slop = msm_read(port, UARTDM_RF);
1446                 c = sp[0];
1447                 count = sizeof(slop) - 1;
1448         }
1449 
1450         return c;
1451 }
1452 
1453 static int msm_poll_get_char(struct uart_port *port)
1454 {
1455         u32 imr;
1456         int c;
1457         struct msm_port *msm_port = UART_TO_MSM(port);
1458 
1459         /* Disable all interrupts */
1460         imr = msm_read(port, UART_IMR);
1461         msm_write(port, 0, UART_IMR);
1462 
1463         if (msm_port->is_uartdm)
1464                 c = msm_poll_get_char_dm(port);
1465         else
1466                 c = msm_poll_get_char_single(port);
1467 
1468         /* Enable interrupts */
1469         msm_write(port, imr, UART_IMR);
1470 
1471         return c;
1472 }
1473 
1474 static void msm_poll_put_char(struct uart_port *port, unsigned char c)
1475 {
1476         u32 imr;
1477         struct msm_port *msm_port = UART_TO_MSM(port);
1478 
1479         /* Disable all interrupts */
1480         imr = msm_read(port, UART_IMR);
1481         msm_write(port, 0, UART_IMR);
1482 
1483         if (msm_port->is_uartdm)
1484                 msm_reset_dm_count(port, 1);
1485 
1486         /* Wait until FIFO is empty */
1487         while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1488                 cpu_relax();
1489 
1490         /* Write a character */
1491         msm_write(port, c, msm_port->is_uartdm ? UARTDM_TF : UART_TF);
1492 
1493         /* Wait until FIFO is empty */
1494         while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1495                 cpu_relax();
1496 
1497         /* Enable interrupts */
1498         msm_write(port, imr, UART_IMR);
1499 }
1500 #endif
1501 
1502 static struct uart_ops msm_uart_pops = {
1503         .tx_empty = msm_tx_empty,
1504         .set_mctrl = msm_set_mctrl,
1505         .get_mctrl = msm_get_mctrl,
1506         .stop_tx = msm_stop_tx,
1507         .start_tx = msm_start_tx,
1508         .stop_rx = msm_stop_rx,
1509         .enable_ms = msm_enable_ms,
1510         .break_ctl = msm_break_ctl,
1511         .startup = msm_startup,
1512         .shutdown = msm_shutdown,
1513         .set_termios = msm_set_termios,
1514         .type = msm_type,
1515         .release_port = msm_release_port,
1516         .request_port = msm_request_port,
1517         .config_port = msm_config_port,
1518         .verify_port = msm_verify_port,
1519         .pm = msm_power,
1520 #ifdef CONFIG_CONSOLE_POLL
1521         .poll_get_char  = msm_poll_get_char,
1522         .poll_put_char  = msm_poll_put_char,
1523 #endif
1524 };
1525 
1526 static struct msm_port msm_uart_ports[] = {
1527         {
1528                 .uart = {
1529                         .iotype = UPIO_MEM,
1530                         .ops = &msm_uart_pops,
1531                         .flags = UPF_BOOT_AUTOCONF,
1532                         .fifosize = 64,
1533                         .line = 0,
1534                 },
1535         },
1536         {
1537                 .uart = {
1538                         .iotype = UPIO_MEM,
1539                         .ops = &msm_uart_pops,
1540                         .flags = UPF_BOOT_AUTOCONF,
1541                         .fifosize = 64,
1542                         .line = 1,
1543                 },
1544         },
1545         {
1546                 .uart = {
1547                         .iotype = UPIO_MEM,
1548                         .ops = &msm_uart_pops,
1549                         .flags = UPF_BOOT_AUTOCONF,
1550                         .fifosize = 64,
1551                         .line = 2,
1552                 },
1553         },
1554 };
1555 
1556 #define UART_NR ARRAY_SIZE(msm_uart_ports)
1557 
1558 static inline struct uart_port *msm_get_port_from_line(unsigned int line)
1559 {
1560         return &msm_uart_ports[line].uart;
1561 }
1562 
1563 #ifdef CONFIG_SERIAL_MSM_CONSOLE
1564 static void __msm_console_write(struct uart_port *port, const char *s,
1565                                 unsigned int count, bool is_uartdm)
1566 {
1567         int i;
1568         int num_newlines = 0;
1569         bool replaced = false;
1570         void __iomem *tf;
1571 
1572         if (is_uartdm)
1573                 tf = port->membase + UARTDM_TF;
1574         else
1575                 tf = port->membase + UART_TF;
1576 
1577         /* Account for newlines that will get a carriage return added */
1578         for (i = 0; i < count; i++)
1579                 if (s[i] == '\n')
1580                         num_newlines++;
1581         count += num_newlines;
1582 
1583         spin_lock(&port->lock);
1584         if (is_uartdm)
1585                 msm_reset_dm_count(port, count);
1586 
1587         i = 0;
1588         while (i < count) {
1589                 int j;
1590                 unsigned int num_chars;
1591                 char buf[4] = { 0 };
1592 
1593                 if (is_uartdm)
1594                         num_chars = min(count - i, (unsigned int)sizeof(buf));
1595                 else
1596                         num_chars = 1;
1597 
1598                 for (j = 0; j < num_chars; j++) {
1599                         char c = *s;
1600 
1601                         if (c == '\n' && !replaced) {
1602                                 buf[j] = '\r';
1603                                 j++;
1604                                 replaced = true;
1605                         }
1606                         if (j < num_chars) {
1607                                 buf[j] = c;
1608                                 s++;
1609                                 replaced = false;
1610                         }
1611                 }
1612 
1613                 while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1614                         cpu_relax();
1615 
1616                 iowrite32_rep(tf, buf, 1);
1617                 i += num_chars;
1618         }
1619         spin_unlock(&port->lock);
1620 }
1621 
1622 static void msm_console_write(struct console *co, const char *s,
1623                               unsigned int count)
1624 {
1625         struct uart_port *port;
1626         struct msm_port *msm_port;
1627 
1628         BUG_ON(co->index < 0 || co->index >= UART_NR);
1629 
1630         port = msm_get_port_from_line(co->index);
1631         msm_port = UART_TO_MSM(port);
1632 
1633         __msm_console_write(port, s, count, msm_port->is_uartdm);
1634 }
1635 
1636 static int __init msm_console_setup(struct console *co, char *options)
1637 {
1638         struct uart_port *port;
1639         int baud = 115200;
1640         int bits = 8;
1641         int parity = 'n';
1642         int flow = 'n';
1643 
1644         if (unlikely(co->index >= UART_NR || co->index < 0))
1645                 return -ENXIO;
1646 
1647         port = msm_get_port_from_line(co->index);
1648 
1649         if (unlikely(!port->membase))
1650                 return -ENXIO;
1651 
1652         msm_init_clock(port);
1653 
1654         if (options)
1655                 uart_parse_options(options, &baud, &parity, &bits, &flow);
1656 
1657         pr_info("msm_serial: console setup on port #%d\n", port->line);
1658 
1659         return uart_set_options(port, co, baud, parity, bits, flow);
1660 }
1661 
1662 static void
1663 msm_serial_early_write(struct console *con, const char *s, unsigned n)
1664 {
1665         struct earlycon_device *dev = con->data;
1666 
1667         __msm_console_write(&dev->port, s, n, false);
1668 }
1669 
1670 static int __init
1671 msm_serial_early_console_setup(struct earlycon_device *device, const char *opt)
1672 {
1673         if (!device->port.membase)
1674                 return -ENODEV;
1675 
1676         device->con->write = msm_serial_early_write;
1677         return 0;
1678 }
1679 OF_EARLYCON_DECLARE(msm_serial, "qcom,msm-uart",
1680                     msm_serial_early_console_setup);
1681 
1682 static void
1683 msm_serial_early_write_dm(struct console *con, const char *s, unsigned n)
1684 {
1685         struct earlycon_device *dev = con->data;
1686 
1687         __msm_console_write(&dev->port, s, n, true);
1688 }
1689 
1690 static int __init
1691 msm_serial_early_console_setup_dm(struct earlycon_device *device,
1692                                   const char *opt)
1693 {
1694         if (!device->port.membase)
1695                 return -ENODEV;
1696 
1697         device->con->write = msm_serial_early_write_dm;
1698         return 0;
1699 }
1700 OF_EARLYCON_DECLARE(msm_serial_dm, "qcom,msm-uartdm",
1701                     msm_serial_early_console_setup_dm);
1702 
1703 static struct uart_driver msm_uart_driver;
1704 
1705 static struct console msm_console = {
1706         .name = "ttyMSM",
1707         .write = msm_console_write,
1708         .device = uart_console_device,
1709         .setup = msm_console_setup,
1710         .flags = CON_PRINTBUFFER,
1711         .index = -1,
1712         .data = &msm_uart_driver,
1713 };
1714 
1715 #define MSM_CONSOLE     (&msm_console)
1716 
1717 #else
1718 #define MSM_CONSOLE     NULL
1719 #endif
1720 
1721 static struct uart_driver msm_uart_driver = {
1722         .owner = THIS_MODULE,
1723         .driver_name = "msm_serial",
1724         .dev_name = "ttyMSM",
1725         .nr = UART_NR,
1726         .cons = MSM_CONSOLE,
1727 };
1728 
1729 static atomic_t msm_uart_next_id = ATOMIC_INIT(0);
1730 
1731 static const struct of_device_id msm_uartdm_table[] = {
1732         { .compatible = "qcom,msm-uartdm-v1.1", .data = (void *)UARTDM_1P1 },
1733         { .compatible = "qcom,msm-uartdm-v1.2", .data = (void *)UARTDM_1P2 },
1734         { .compatible = "qcom,msm-uartdm-v1.3", .data = (void *)UARTDM_1P3 },
1735         { .compatible = "qcom,msm-uartdm-v1.4", .data = (void *)UARTDM_1P4 },
1736         { }
1737 };
1738 
1739 static int msm_serial_probe(struct platform_device *pdev)
1740 {
1741         struct msm_port *msm_port;
1742         struct resource *resource;
1743         struct uart_port *port;
1744         const struct of_device_id *id;
1745         int irq, line;
1746 
1747         if (pdev->dev.of_node)
1748                 line = of_alias_get_id(pdev->dev.of_node, "serial");
1749         else
1750                 line = pdev->id;
1751 
1752         if (line < 0)
1753                 line = atomic_inc_return(&msm_uart_next_id) - 1;
1754 
1755         if (unlikely(line < 0 || line >= UART_NR))
1756                 return -ENXIO;
1757 
1758         dev_info(&pdev->dev, "msm_serial: detected port #%d\n", line);
1759 
1760         port = msm_get_port_from_line(line);
1761         port->dev = &pdev->dev;
1762         msm_port = UART_TO_MSM(port);
1763 
1764         id = of_match_device(msm_uartdm_table, &pdev->dev);
1765         if (id)
1766                 msm_port->is_uartdm = (unsigned long)id->data;
1767         else
1768                 msm_port->is_uartdm = 0;
1769 
1770         msm_port->clk = devm_clk_get(&pdev->dev, "core");
1771         if (IS_ERR(msm_port->clk))
1772                 return PTR_ERR(msm_port->clk);
1773 
1774         if (msm_port->is_uartdm) {
1775                 msm_port->pclk = devm_clk_get(&pdev->dev, "iface");
1776                 if (IS_ERR(msm_port->pclk))
1777                         return PTR_ERR(msm_port->pclk);
1778         }
1779 
1780         port->uartclk = clk_get_rate(msm_port->clk);
1781         dev_info(&pdev->dev, "uartclk = %d\n", port->uartclk);
1782 
1783         resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1784         if (unlikely(!resource))
1785                 return -ENXIO;
1786         port->mapbase = resource->start;
1787 
1788         irq = platform_get_irq(pdev, 0);
1789         if (unlikely(irq < 0))
1790                 return -ENXIO;
1791         port->irq = irq;
1792 
1793         platform_set_drvdata(pdev, port);
1794 
1795         return uart_add_one_port(&msm_uart_driver, port);
1796 }
1797 
1798 static int msm_serial_remove(struct platform_device *pdev)
1799 {
1800         struct uart_port *port = platform_get_drvdata(pdev);
1801 
1802         uart_remove_one_port(&msm_uart_driver, port);
1803 
1804         return 0;
1805 }
1806 
1807 static const struct of_device_id msm_match_table[] = {
1808         { .compatible = "qcom,msm-uart" },
1809         { .compatible = "qcom,msm-uartdm" },
1810         {}
1811 };
1812 
1813 static struct platform_driver msm_platform_driver = {
1814         .remove = msm_serial_remove,
1815         .probe = msm_serial_probe,
1816         .driver = {
1817                 .name = "msm_serial",
1818                 .of_match_table = msm_match_table,
1819         },
1820 };
1821 
1822 static int __init msm_serial_init(void)
1823 {
1824         int ret;
1825 
1826         ret = uart_register_driver(&msm_uart_driver);
1827         if (unlikely(ret))
1828                 return ret;
1829 
1830         ret = platform_driver_register(&msm_platform_driver);
1831         if (unlikely(ret))
1832                 uart_unregister_driver(&msm_uart_driver);
1833 
1834         pr_info("msm_serial: driver initialized\n");
1835 
1836         return ret;
1837 }
1838 
1839 static void __exit msm_serial_exit(void)
1840 {
1841         platform_driver_unregister(&msm_platform_driver);
1842         uart_unregister_driver(&msm_uart_driver);
1843 }
1844 
1845 module_init(msm_serial_init);
1846 module_exit(msm_serial_exit);
1847 
1848 MODULE_AUTHOR("Robert Love <rlove@google.com>");
1849 MODULE_DESCRIPTION("Driver for msm7x serial device");
1850 MODULE_LICENSE("GPL");
1851 

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