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Linux/drivers/platform/x86/apple-gmux.c

  1 /*
  2  *  Gmux driver for Apple laptops
  3  *
  4  *  Copyright (C) Canonical Ltd. <seth.forshee@canonical.com>
  5  *  Copyright (C) 2010-2012 Andreas Heider <andreas@meetr.de>
  6  *  Copyright (C) 2015 Lukas Wunner <lukas@wunner.de>
  7  *
  8  *  This program is free software; you can redistribute it and/or modify
  9  *  it under the terms of the GNU General Public License version 2 as
 10  *  published by the Free Software Foundation.
 11  */
 12 
 13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 14 
 15 #include <linux/module.h>
 16 #include <linux/kernel.h>
 17 #include <linux/init.h>
 18 #include <linux/backlight.h>
 19 #include <linux/acpi.h>
 20 #include <linux/pnp.h>
 21 #include <linux/apple_bl.h>
 22 #include <linux/slab.h>
 23 #include <linux/delay.h>
 24 #include <linux/pci.h>
 25 #include <linux/vga_switcheroo.h>
 26 #include <linux/vgaarb.h>
 27 #include <acpi/video.h>
 28 #include <asm/io.h>
 29 
 30 /**
 31  * DOC: Overview
 32  *
 33  * :1:  http://www.latticesemi.com/en/Products/FPGAandCPLD/LatticeXP2.aspx
 34  * :2:  http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp
 35  *
 36  * gmux is a microcontroller built into the MacBook Pro to support dual GPUs:
 37  * A {1}[Lattice XP2] on pre-retinas, a {2}[Renesas R4F2113] on retinas.
 38  *
 39  * (The MacPro6,1 2013 also has a gmux, however it is unclear why since it has
 40  * dual GPUs but no built-in display.)
 41  *
 42  * gmux is connected to the LPC bus of the southbridge. Its I/O ports are
 43  * accessed differently depending on the microcontroller: Driver functions
 44  * to access a pre-retina gmux are infixed `_pio_`, those for a retina gmux
 45  * are infixed `_index_`.
 46  */
 47 
 48 struct apple_gmux_data {
 49         unsigned long iostart;
 50         unsigned long iolen;
 51         bool indexed;
 52         struct mutex index_lock;
 53 
 54         struct pci_dev *pdev;
 55         struct backlight_device *bdev;
 56 
 57         /* switcheroo data */
 58         acpi_handle dhandle;
 59         int gpe;
 60         enum vga_switcheroo_client_id resume_client_id;
 61         enum vga_switcheroo_state power_state;
 62         struct completion powerchange_done;
 63 };
 64 
 65 static struct apple_gmux_data *apple_gmux_data;
 66 
 67 /*
 68  * gmux port offsets. Many of these are not yet used, but may be in the
 69  * future, and it's useful to have them documented here anyhow.
 70  */
 71 #define GMUX_PORT_VERSION_MAJOR         0x04
 72 #define GMUX_PORT_VERSION_MINOR         0x05
 73 #define GMUX_PORT_VERSION_RELEASE       0x06
 74 #define GMUX_PORT_SWITCH_DISPLAY        0x10
 75 #define GMUX_PORT_SWITCH_GET_DISPLAY    0x11
 76 #define GMUX_PORT_INTERRUPT_ENABLE      0x14
 77 #define GMUX_PORT_INTERRUPT_STATUS      0x16
 78 #define GMUX_PORT_SWITCH_DDC            0x28
 79 #define GMUX_PORT_SWITCH_EXTERNAL       0x40
 80 #define GMUX_PORT_SWITCH_GET_EXTERNAL   0x41
 81 #define GMUX_PORT_DISCRETE_POWER        0x50
 82 #define GMUX_PORT_MAX_BRIGHTNESS        0x70
 83 #define GMUX_PORT_BRIGHTNESS            0x74
 84 #define GMUX_PORT_VALUE                 0xc2
 85 #define GMUX_PORT_READ                  0xd0
 86 #define GMUX_PORT_WRITE                 0xd4
 87 
 88 #define GMUX_MIN_IO_LEN                 (GMUX_PORT_BRIGHTNESS + 4)
 89 
 90 #define GMUX_INTERRUPT_ENABLE           0xff
 91 #define GMUX_INTERRUPT_DISABLE          0x00
 92 
 93 #define GMUX_INTERRUPT_STATUS_ACTIVE    0
 94 #define GMUX_INTERRUPT_STATUS_DISPLAY   (1 << 0)
 95 #define GMUX_INTERRUPT_STATUS_POWER     (1 << 2)
 96 #define GMUX_INTERRUPT_STATUS_HOTPLUG   (1 << 3)
 97 
 98 #define GMUX_BRIGHTNESS_MASK            0x00ffffff
 99 #define GMUX_MAX_BRIGHTNESS             GMUX_BRIGHTNESS_MASK
100 
101 static u8 gmux_pio_read8(struct apple_gmux_data *gmux_data, int port)
102 {
103         return inb(gmux_data->iostart + port);
104 }
105 
106 static void gmux_pio_write8(struct apple_gmux_data *gmux_data, int port,
107                                u8 val)
108 {
109         outb(val, gmux_data->iostart + port);
110 }
111 
112 static u32 gmux_pio_read32(struct apple_gmux_data *gmux_data, int port)
113 {
114         return inl(gmux_data->iostart + port);
115 }
116 
117 static void gmux_pio_write32(struct apple_gmux_data *gmux_data, int port,
118                              u32 val)
119 {
120         int i;
121         u8 tmpval;
122 
123         for (i = 0; i < 4; i++) {
124                 tmpval = (val >> (i * 8)) & 0xff;
125                 outb(tmpval, gmux_data->iostart + port + i);
126         }
127 }
128 
129 static int gmux_index_wait_ready(struct apple_gmux_data *gmux_data)
130 {
131         int i = 200;
132         u8 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
133 
134         while (i && (gwr & 0x01)) {
135                 inb(gmux_data->iostart + GMUX_PORT_READ);
136                 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
137                 udelay(100);
138                 i--;
139         }
140 
141         return !!i;
142 }
143 
144 static int gmux_index_wait_complete(struct apple_gmux_data *gmux_data)
145 {
146         int i = 200;
147         u8 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
148 
149         while (i && !(gwr & 0x01)) {
150                 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
151                 udelay(100);
152                 i--;
153         }
154 
155         if (gwr & 0x01)
156                 inb(gmux_data->iostart + GMUX_PORT_READ);
157 
158         return !!i;
159 }
160 
161 static u8 gmux_index_read8(struct apple_gmux_data *gmux_data, int port)
162 {
163         u8 val;
164 
165         mutex_lock(&gmux_data->index_lock);
166         gmux_index_wait_ready(gmux_data);
167         outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
168         gmux_index_wait_complete(gmux_data);
169         val = inb(gmux_data->iostart + GMUX_PORT_VALUE);
170         mutex_unlock(&gmux_data->index_lock);
171 
172         return val;
173 }
174 
175 static void gmux_index_write8(struct apple_gmux_data *gmux_data, int port,
176                               u8 val)
177 {
178         mutex_lock(&gmux_data->index_lock);
179         outb(val, gmux_data->iostart + GMUX_PORT_VALUE);
180         gmux_index_wait_ready(gmux_data);
181         outb(port & 0xff, gmux_data->iostart + GMUX_PORT_WRITE);
182         gmux_index_wait_complete(gmux_data);
183         mutex_unlock(&gmux_data->index_lock);
184 }
185 
186 static u32 gmux_index_read32(struct apple_gmux_data *gmux_data, int port)
187 {
188         u32 val;
189 
190         mutex_lock(&gmux_data->index_lock);
191         gmux_index_wait_ready(gmux_data);
192         outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
193         gmux_index_wait_complete(gmux_data);
194         val = inl(gmux_data->iostart + GMUX_PORT_VALUE);
195         mutex_unlock(&gmux_data->index_lock);
196 
197         return val;
198 }
199 
200 static void gmux_index_write32(struct apple_gmux_data *gmux_data, int port,
201                                u32 val)
202 {
203         int i;
204         u8 tmpval;
205 
206         mutex_lock(&gmux_data->index_lock);
207 
208         for (i = 0; i < 4; i++) {
209                 tmpval = (val >> (i * 8)) & 0xff;
210                 outb(tmpval, gmux_data->iostart + GMUX_PORT_VALUE + i);
211         }
212 
213         gmux_index_wait_ready(gmux_data);
214         outb(port & 0xff, gmux_data->iostart + GMUX_PORT_WRITE);
215         gmux_index_wait_complete(gmux_data);
216         mutex_unlock(&gmux_data->index_lock);
217 }
218 
219 static u8 gmux_read8(struct apple_gmux_data *gmux_data, int port)
220 {
221         if (gmux_data->indexed)
222                 return gmux_index_read8(gmux_data, port);
223         else
224                 return gmux_pio_read8(gmux_data, port);
225 }
226 
227 static void gmux_write8(struct apple_gmux_data *gmux_data, int port, u8 val)
228 {
229         if (gmux_data->indexed)
230                 gmux_index_write8(gmux_data, port, val);
231         else
232                 gmux_pio_write8(gmux_data, port, val);
233 }
234 
235 static u32 gmux_read32(struct apple_gmux_data *gmux_data, int port)
236 {
237         if (gmux_data->indexed)
238                 return gmux_index_read32(gmux_data, port);
239         else
240                 return gmux_pio_read32(gmux_data, port);
241 }
242 
243 static void gmux_write32(struct apple_gmux_data *gmux_data, int port,
244                              u32 val)
245 {
246         if (gmux_data->indexed)
247                 gmux_index_write32(gmux_data, port, val);
248         else
249                 gmux_pio_write32(gmux_data, port, val);
250 }
251 
252 static bool gmux_is_indexed(struct apple_gmux_data *gmux_data)
253 {
254         u16 val;
255 
256         outb(0xaa, gmux_data->iostart + 0xcc);
257         outb(0x55, gmux_data->iostart + 0xcd);
258         outb(0x00, gmux_data->iostart + 0xce);
259 
260         val = inb(gmux_data->iostart + 0xcc) |
261                 (inb(gmux_data->iostart + 0xcd) << 8);
262 
263         if (val == 0x55aa)
264                 return true;
265 
266         return false;
267 }
268 
269 /**
270  * DOC: Backlight control
271  *
272  * :3:  http://www.ti.com/lit/ds/symlink/lp8543.pdf
273  * :4:  http://www.ti.com/lit/ds/symlink/lp8545.pdf
274  *
275  * On single GPU MacBooks, the PWM signal for the backlight is generated by
276  * the GPU. On dual GPU MacBook Pros by contrast, either GPU may be suspended
277  * to conserve energy. Hence the PWM signal needs to be generated by a separate
278  * backlight driver which is controlled by gmux. The earliest generation
279  * MBP5 2008/09 uses a {3}[TI LP8543] backlight driver. All newer models
280  * use a {4}[TI LP8545].
281  */
282 
283 static int gmux_get_brightness(struct backlight_device *bd)
284 {
285         struct apple_gmux_data *gmux_data = bl_get_data(bd);
286         return gmux_read32(gmux_data, GMUX_PORT_BRIGHTNESS) &
287                GMUX_BRIGHTNESS_MASK;
288 }
289 
290 static int gmux_update_status(struct backlight_device *bd)
291 {
292         struct apple_gmux_data *gmux_data = bl_get_data(bd);
293         u32 brightness = bd->props.brightness;
294 
295         if (bd->props.state & BL_CORE_SUSPENDED)
296                 return 0;
297 
298         gmux_write32(gmux_data, GMUX_PORT_BRIGHTNESS, brightness);
299 
300         return 0;
301 }
302 
303 static const struct backlight_ops gmux_bl_ops = {
304         .options = BL_CORE_SUSPENDRESUME,
305         .get_brightness = gmux_get_brightness,
306         .update_status = gmux_update_status,
307 };
308 
309 /**
310  * DOC: Graphics mux
311  *
312  * :5:  http://pimg-fpiw.uspto.gov/fdd/07/870/086/0.pdf
313  * :6:  http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
314  * :7:  http://www.ti.com/lit/ds/symlink/hd3ss212.pdf
315  * :8:  https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf
316  * :9:  http://www.ti.com/lit/ds/symlink/sn74lv4066a.pdf
317  * :10: http://pdf.datasheetarchive.com/indexerfiles/Datasheets-SW16/DSASW00308511.pdf
318  * :11: http://www.ti.com/lit/ds/symlink/ts3ds10224.pdf
319  *
320  * On pre-retinas, the LVDS outputs of both GPUs feed into gmux which muxes
321  * either of them to the panel. One of the tricks gmux has up its sleeve is
322  * to lengthen the blanking interval of its output during a switch to
323  * synchronize it with the GPU switched to. This allows for a flicker-free
324  * switch that is imperceptible by the user ({5}[US 8,687,007 B2]).
325  *
326  * On retinas, muxing is no longer done by gmux itself, but by a separate
327  * chip which is controlled by gmux. The chip is triple sourced, it is
328  * either an {6}[NXP CBTL06142], {7}[TI HD3SS212] or {8}[Pericom PI3VDP12412].
329  * The panel is driven with eDP instead of LVDS since the pixel clock
330  * required for retina resolution exceeds LVDS' limits.
331  *
332  * Pre-retinas are able to switch the panel's DDC pins separately.
333  * This is handled by a {9}[TI SN74LV4066A] which is controlled by gmux.
334  * The inactive GPU can thus probe the panel's EDID without switching over
335  * the entire panel. Retinas lack this functionality as the chips used for
336  * eDP muxing are incapable of switching the AUX channel separately (see
337  * the linked data sheets, Pericom would be capable but this is unused).
338  * However the retina panel has the NO_AUX_HANDSHAKE_LINK_TRAINING bit set
339  * in its DPCD, allowing the inactive GPU to skip the AUX handshake and
340  * set up the output with link parameters pre-calibrated by the active GPU.
341  *
342  * The external DP port is only fully switchable on the first two unibody
343  * MacBook Pro generations, MBP5 2008/09 and MBP6 2010. This is done by an
344  * {6}[NXP CBTL06141] which is controlled by gmux. It's the predecessor of the
345  * eDP mux on retinas, the difference being support for 2.7 versus 5.4 Gbit/s.
346  *
347  * The following MacBook Pro generations replaced the external DP port with a
348  * combined DP/Thunderbolt port and lost the ability to switch it between GPUs,
349  * connecting it either to the discrete GPU or the Thunderbolt controller.
350  * Oddly enough, while the full port is no longer switchable, AUX and HPD
351  * are still switchable by way of an {10}[NXP CBTL03062] (on pre-retinas
352  * MBP8 2011 and MBP9 2012) or two {11}[TI TS3DS10224] (on retinas) under the
353  * control of gmux. Since the integrated GPU is missing the main link,
354  * external displays appear to it as phantoms which fail to link-train.
355  *
356  * gmux receives the HPD signal of all display connectors and sends an
357  * interrupt on hotplug. On generations which cannot switch external ports,
358  * the discrete GPU can then be woken to drive the newly connected display.
359  * The ability to switch AUX on these generations could be used to improve
360  * reliability of hotplug detection by having the integrated GPU poll the
361  * ports while the discrete GPU is asleep, but currently we do not make use
362  * of this feature.
363  *
364  * gmux' initial switch state on bootup is user configurable via the EFI
365  * variable `gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9` (5th byte,
366  * 1 = IGD, 0 = DIS). Based on this setting, the EFI firmware tells gmux to
367  * switch the panel and the external DP connector and allocates a framebuffer
368  * for the selected GPU.
369  */
370 
371 static int gmux_switchto(enum vga_switcheroo_client_id id)
372 {
373         if (id == VGA_SWITCHEROO_IGD) {
374                 gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1);
375                 gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DISPLAY, 2);
376                 gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 2);
377         } else {
378                 gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2);
379                 gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DISPLAY, 3);
380                 gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 3);
381         }
382 
383         return 0;
384 }
385 
386 /**
387  * DOC: Power control
388  *
389  * gmux is able to cut power to the discrete GPU. It automatically takes care
390  * of the correct sequence to tear down and bring up the power rails for
391  * core voltage, VRAM and PCIe.
392  */
393 
394 static int gmux_set_discrete_state(struct apple_gmux_data *gmux_data,
395                                    enum vga_switcheroo_state state)
396 {
397         reinit_completion(&gmux_data->powerchange_done);
398 
399         if (state == VGA_SWITCHEROO_ON) {
400                 gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 1);
401                 gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 3);
402                 pr_debug("Discrete card powered up\n");
403         } else {
404                 gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 1);
405                 gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 0);
406                 pr_debug("Discrete card powered down\n");
407         }
408 
409         gmux_data->power_state = state;
410 
411         if (gmux_data->gpe >= 0 &&
412             !wait_for_completion_interruptible_timeout(&gmux_data->powerchange_done,
413                                                        msecs_to_jiffies(200)))
414                 pr_warn("Timeout waiting for gmux switch to complete\n");
415 
416         return 0;
417 }
418 
419 static int gmux_set_power_state(enum vga_switcheroo_client_id id,
420                                 enum vga_switcheroo_state state)
421 {
422         if (id == VGA_SWITCHEROO_IGD)
423                 return 0;
424 
425         return gmux_set_discrete_state(apple_gmux_data, state);
426 }
427 
428 static int gmux_get_client_id(struct pci_dev *pdev)
429 {
430         /*
431          * Early Macbook Pros with switchable graphics use nvidia
432          * integrated graphics. Hardcode that the 9400M is integrated.
433          */
434         if (pdev->vendor == PCI_VENDOR_ID_INTEL)
435                 return VGA_SWITCHEROO_IGD;
436         else if (pdev->vendor == PCI_VENDOR_ID_NVIDIA &&
437                  pdev->device == 0x0863)
438                 return VGA_SWITCHEROO_IGD;
439         else
440                 return VGA_SWITCHEROO_DIS;
441 }
442 
443 static enum vga_switcheroo_client_id
444 gmux_active_client(struct apple_gmux_data *gmux_data)
445 {
446         if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_DISPLAY) == 2)
447                 return VGA_SWITCHEROO_IGD;
448 
449         return VGA_SWITCHEROO_DIS;
450 }
451 
452 static const struct vga_switcheroo_handler gmux_handler = {
453         .switchto = gmux_switchto,
454         .power_state = gmux_set_power_state,
455         .get_client_id = gmux_get_client_id,
456 };
457 
458 /**
459  * DOC: Interrupt
460  *
461  * gmux is also connected to a GPIO pin of the southbridge and thereby is able
462  * to trigger an ACPI GPE. On the MBP5 2008/09 it's GPIO pin 22 of the Nvidia
463  * MCP79, on all following generations it's GPIO pin 6 of the Intel PCH.
464  * The GPE merely signals that an interrupt occurred, the actual type of event
465  * is identified by reading a gmux register.
466  */
467 
468 static inline void gmux_disable_interrupts(struct apple_gmux_data *gmux_data)
469 {
470         gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
471                     GMUX_INTERRUPT_DISABLE);
472 }
473 
474 static inline void gmux_enable_interrupts(struct apple_gmux_data *gmux_data)
475 {
476         gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
477                     GMUX_INTERRUPT_ENABLE);
478 }
479 
480 static inline u8 gmux_interrupt_get_status(struct apple_gmux_data *gmux_data)
481 {
482         return gmux_read8(gmux_data, GMUX_PORT_INTERRUPT_STATUS);
483 }
484 
485 static void gmux_clear_interrupts(struct apple_gmux_data *gmux_data)
486 {
487         u8 status;
488 
489         /* to clear interrupts write back current status */
490         status = gmux_interrupt_get_status(gmux_data);
491         gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_STATUS, status);
492 }
493 
494 static void gmux_notify_handler(acpi_handle device, u32 value, void *context)
495 {
496         u8 status;
497         struct pnp_dev *pnp = (struct pnp_dev *)context;
498         struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
499 
500         status = gmux_interrupt_get_status(gmux_data);
501         gmux_disable_interrupts(gmux_data);
502         pr_debug("Notify handler called: status %d\n", status);
503 
504         gmux_clear_interrupts(gmux_data);
505         gmux_enable_interrupts(gmux_data);
506 
507         if (status & GMUX_INTERRUPT_STATUS_POWER)
508                 complete(&gmux_data->powerchange_done);
509 }
510 
511 static int gmux_suspend(struct device *dev)
512 {
513         struct pnp_dev *pnp = to_pnp_dev(dev);
514         struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
515 
516         gmux_data->resume_client_id = gmux_active_client(gmux_data);
517         gmux_disable_interrupts(gmux_data);
518         return 0;
519 }
520 
521 static int gmux_resume(struct device *dev)
522 {
523         struct pnp_dev *pnp = to_pnp_dev(dev);
524         struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
525 
526         gmux_enable_interrupts(gmux_data);
527         gmux_switchto(gmux_data->resume_client_id);
528         if (gmux_data->power_state == VGA_SWITCHEROO_OFF)
529                 gmux_set_discrete_state(gmux_data, gmux_data->power_state);
530         return 0;
531 }
532 
533 static struct pci_dev *gmux_get_io_pdev(void)
534 {
535         struct pci_dev *pdev = NULL;
536 
537         while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev))) {
538                 u16 cmd;
539 
540                 pci_read_config_word(pdev, PCI_COMMAND, &cmd);
541                 if (!(cmd & PCI_COMMAND_IO))
542                         continue;
543 
544                 return pdev;
545         }
546 
547         return NULL;
548 }
549 
550 static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
551 {
552         struct apple_gmux_data *gmux_data;
553         struct resource *res;
554         struct backlight_properties props;
555         struct backlight_device *bdev;
556         u8 ver_major, ver_minor, ver_release;
557         int ret = -ENXIO;
558         acpi_status status;
559         unsigned long long gpe;
560         struct pci_dev *pdev = NULL;
561 
562         if (apple_gmux_data)
563                 return -EBUSY;
564 
565         gmux_data = kzalloc(sizeof(*gmux_data), GFP_KERNEL);
566         if (!gmux_data)
567                 return -ENOMEM;
568         pnp_set_drvdata(pnp, gmux_data);
569 
570         res = pnp_get_resource(pnp, IORESOURCE_IO, 0);
571         if (!res) {
572                 pr_err("Failed to find gmux I/O resource\n");
573                 goto err_free;
574         }
575 
576         gmux_data->iostart = res->start;
577         gmux_data->iolen = res->end - res->start;
578 
579         if (gmux_data->iolen < GMUX_MIN_IO_LEN) {
580                 pr_err("gmux I/O region too small (%lu < %u)\n",
581                        gmux_data->iolen, GMUX_MIN_IO_LEN);
582                 goto err_free;
583         }
584 
585         if (!request_region(gmux_data->iostart, gmux_data->iolen,
586                             "Apple gmux")) {
587                 pr_err("gmux I/O already in use\n");
588                 goto err_free;
589         }
590 
591         /*
592          * Invalid version information may indicate either that the gmux
593          * device isn't present or that it's a new one that uses indexed
594          * io
595          */
596 
597         ver_major = gmux_read8(gmux_data, GMUX_PORT_VERSION_MAJOR);
598         ver_minor = gmux_read8(gmux_data, GMUX_PORT_VERSION_MINOR);
599         ver_release = gmux_read8(gmux_data, GMUX_PORT_VERSION_RELEASE);
600         if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
601                 if (gmux_is_indexed(gmux_data)) {
602                         u32 version;
603                         mutex_init(&gmux_data->index_lock);
604                         gmux_data->indexed = true;
605                         version = gmux_read32(gmux_data,
606                                 GMUX_PORT_VERSION_MAJOR);
607                         ver_major = (version >> 24) & 0xff;
608                         ver_minor = (version >> 16) & 0xff;
609                         ver_release = (version >> 8) & 0xff;
610                 } else {
611                         pr_info("gmux device not present or IO disabled\n");
612                         ret = -ENODEV;
613                         goto err_release;
614                 }
615         }
616         pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor,
617                 ver_release, (gmux_data->indexed ? "indexed" : "classic"));
618 
619         /*
620          * Apple systems with gmux are EFI based and normally don't use
621          * VGA. In addition changing IO+MEM ownership between IGP and dGPU
622          * disables IO/MEM used for backlight control on some systems.
623          * Lock IO+MEM to GPU with active IO to prevent switch.
624          */
625         pdev = gmux_get_io_pdev();
626         if (pdev && vga_tryget(pdev,
627                                VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM)) {
628                 pr_err("IO+MEM vgaarb-locking for PCI:%s failed\n",
629                         pci_name(pdev));
630                 ret = -EBUSY;
631                 goto err_release;
632         } else if (pdev)
633                 pr_info("locked IO for PCI:%s\n", pci_name(pdev));
634         gmux_data->pdev = pdev;
635 
636         memset(&props, 0, sizeof(props));
637         props.type = BACKLIGHT_PLATFORM;
638         props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);
639 
640         /*
641          * Currently it's assumed that the maximum brightness is less than
642          * 2^24 for compatibility with old gmux versions. Cap the max
643          * brightness at this value, but print a warning if the hardware
644          * reports something higher so that it can be fixed.
645          */
646         if (WARN_ON(props.max_brightness > GMUX_MAX_BRIGHTNESS))
647                 props.max_brightness = GMUX_MAX_BRIGHTNESS;
648 
649         bdev = backlight_device_register("gmux_backlight", &pnp->dev,
650                                          gmux_data, &gmux_bl_ops, &props);
651         if (IS_ERR(bdev)) {
652                 ret = PTR_ERR(bdev);
653                 goto err_release;
654         }
655 
656         gmux_data->bdev = bdev;
657         bdev->props.brightness = gmux_get_brightness(bdev);
658         backlight_update_status(bdev);
659 
660         /*
661          * The backlight situation on Macs is complicated. If the gmux is
662          * present it's the best choice, because it always works for
663          * backlight control and supports more levels than other options.
664          * Disable the other backlight choices.
665          */
666         acpi_video_set_dmi_backlight_type(acpi_backlight_vendor);
667         apple_bl_unregister();
668 
669         gmux_data->power_state = VGA_SWITCHEROO_ON;
670 
671         gmux_data->dhandle = ACPI_HANDLE(&pnp->dev);
672         if (!gmux_data->dhandle) {
673                 pr_err("Cannot find acpi handle for pnp device %s\n",
674                        dev_name(&pnp->dev));
675                 ret = -ENODEV;
676                 goto err_notify;
677         }
678 
679         status = acpi_evaluate_integer(gmux_data->dhandle, "GMGP", NULL, &gpe);
680         if (ACPI_SUCCESS(status)) {
681                 gmux_data->gpe = (int)gpe;
682 
683                 status = acpi_install_notify_handler(gmux_data->dhandle,
684                                                      ACPI_DEVICE_NOTIFY,
685                                                      &gmux_notify_handler, pnp);
686                 if (ACPI_FAILURE(status)) {
687                         pr_err("Install notify handler failed: %s\n",
688                                acpi_format_exception(status));
689                         ret = -ENODEV;
690                         goto err_notify;
691                 }
692 
693                 status = acpi_enable_gpe(NULL, gmux_data->gpe);
694                 if (ACPI_FAILURE(status)) {
695                         pr_err("Cannot enable gpe: %s\n",
696                                acpi_format_exception(status));
697                         goto err_enable_gpe;
698                 }
699         } else {
700                 pr_warn("No GPE found for gmux\n");
701                 gmux_data->gpe = -1;
702         }
703 
704         apple_gmux_data = gmux_data;
705         init_completion(&gmux_data->powerchange_done);
706         gmux_enable_interrupts(gmux_data);
707 
708         if (vga_switcheroo_register_handler(&gmux_handler)) {
709                 ret = -ENODEV;
710                 goto err_register_handler;
711         }
712 
713         return 0;
714 
715 err_register_handler:
716         gmux_disable_interrupts(gmux_data);
717         apple_gmux_data = NULL;
718         if (gmux_data->gpe >= 0)
719                 acpi_disable_gpe(NULL, gmux_data->gpe);
720 err_enable_gpe:
721         if (gmux_data->gpe >= 0)
722                 acpi_remove_notify_handler(gmux_data->dhandle,
723                                            ACPI_DEVICE_NOTIFY,
724                                            &gmux_notify_handler);
725 err_notify:
726         backlight_device_unregister(bdev);
727 err_release:
728         if (gmux_data->pdev)
729                 vga_put(gmux_data->pdev,
730                         VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
731         pci_dev_put(pdev);
732         release_region(gmux_data->iostart, gmux_data->iolen);
733 err_free:
734         kfree(gmux_data);
735         return ret;
736 }
737 
738 static void gmux_remove(struct pnp_dev *pnp)
739 {
740         struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
741 
742         vga_switcheroo_unregister_handler();
743         gmux_disable_interrupts(gmux_data);
744         if (gmux_data->gpe >= 0) {
745                 acpi_disable_gpe(NULL, gmux_data->gpe);
746                 acpi_remove_notify_handler(gmux_data->dhandle,
747                                            ACPI_DEVICE_NOTIFY,
748                                            &gmux_notify_handler);
749         }
750 
751         if (gmux_data->pdev) {
752                 vga_put(gmux_data->pdev,
753                         VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
754                 pci_dev_put(gmux_data->pdev);
755         }
756         backlight_device_unregister(gmux_data->bdev);
757 
758         release_region(gmux_data->iostart, gmux_data->iolen);
759         apple_gmux_data = NULL;
760         kfree(gmux_data);
761 
762         acpi_video_register();
763         apple_bl_register();
764 }
765 
766 static const struct pnp_device_id gmux_device_ids[] = {
767         {"APP000B", 0},
768         {"", 0}
769 };
770 
771 static const struct dev_pm_ops gmux_dev_pm_ops = {
772         .suspend = gmux_suspend,
773         .resume = gmux_resume,
774 };
775 
776 static struct pnp_driver gmux_pnp_driver = {
777         .name           = "apple-gmux",
778         .probe          = gmux_probe,
779         .remove         = gmux_remove,
780         .id_table       = gmux_device_ids,
781         .driver         = {
782                         .pm = &gmux_dev_pm_ops,
783         },
784 };
785 
786 module_pnp_driver(gmux_pnp_driver);
787 MODULE_AUTHOR("Seth Forshee <seth.forshee@canonical.com>");
788 MODULE_DESCRIPTION("Apple Gmux Driver");
789 MODULE_LICENSE("GPL");
790 MODULE_DEVICE_TABLE(pnp, gmux_device_ids);
791 

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