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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/apple-gmux.h>
 23 #include <linux/slab.h>
 24 #include <linux/delay.h>
 25 #include <linux/pci.h>
 26 #include <linux/vga_switcheroo.h>
 27 #include <linux/vgaarb.h>
 28 #include <acpi/video.h>
 29 #include <asm/io.h>
 30 
 31 /**
 32  * DOC: Overview
 33  *
 34  * gmux is a microcontroller built into the MacBook Pro to support dual GPUs:
 35  * A `Lattice XP2`_ on pre-retinas, a `Renesas R4F2113`_ on retinas.
 36  *
 37  * (The MacPro6,1 2013 also has a gmux, however it is unclear why since it has
 38  * dual GPUs but no built-in display.)
 39  *
 40  * gmux is connected to the LPC bus of the southbridge. Its I/O ports are
 41  * accessed differently depending on the microcontroller: Driver functions
 42  * to access a pre-retina gmux are infixed ``_pio_``, those for a retina gmux
 43  * are infixed ``_index_``.
 44  *
 45  * .. _Lattice XP2:
 46  *     http://www.latticesemi.com/en/Products/FPGAandCPLD/LatticeXP2.aspx
 47  * .. _Renesas R4F2113:
 48  *     http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp
 49  */
 50 
 51 struct apple_gmux_data {
 52         unsigned long iostart;
 53         unsigned long iolen;
 54         bool indexed;
 55         struct mutex index_lock;
 56 
 57         struct pci_dev *pdev;
 58         struct backlight_device *bdev;
 59 
 60         /* switcheroo data */
 61         acpi_handle dhandle;
 62         int gpe;
 63         enum vga_switcheroo_client_id switch_state_display;
 64         enum vga_switcheroo_client_id switch_state_ddc;
 65         enum vga_switcheroo_client_id switch_state_external;
 66         enum vga_switcheroo_state power_state;
 67         struct completion powerchange_done;
 68 };
 69 
 70 static struct apple_gmux_data *apple_gmux_data;
 71 
 72 /*
 73  * gmux port offsets. Many of these are not yet used, but may be in the
 74  * future, and it's useful to have them documented here anyhow.
 75  */
 76 #define GMUX_PORT_VERSION_MAJOR         0x04
 77 #define GMUX_PORT_VERSION_MINOR         0x05
 78 #define GMUX_PORT_VERSION_RELEASE       0x06
 79 #define GMUX_PORT_SWITCH_DISPLAY        0x10
 80 #define GMUX_PORT_SWITCH_GET_DISPLAY    0x11
 81 #define GMUX_PORT_INTERRUPT_ENABLE      0x14
 82 #define GMUX_PORT_INTERRUPT_STATUS      0x16
 83 #define GMUX_PORT_SWITCH_DDC            0x28
 84 #define GMUX_PORT_SWITCH_EXTERNAL       0x40
 85 #define GMUX_PORT_SWITCH_GET_EXTERNAL   0x41
 86 #define GMUX_PORT_DISCRETE_POWER        0x50
 87 #define GMUX_PORT_MAX_BRIGHTNESS        0x70
 88 #define GMUX_PORT_BRIGHTNESS            0x74
 89 #define GMUX_PORT_VALUE                 0xc2
 90 #define GMUX_PORT_READ                  0xd0
 91 #define GMUX_PORT_WRITE                 0xd4
 92 
 93 #define GMUX_MIN_IO_LEN                 (GMUX_PORT_BRIGHTNESS + 4)
 94 
 95 #define GMUX_INTERRUPT_ENABLE           0xff
 96 #define GMUX_INTERRUPT_DISABLE          0x00
 97 
 98 #define GMUX_INTERRUPT_STATUS_ACTIVE    0
 99 #define GMUX_INTERRUPT_STATUS_DISPLAY   (1 << 0)
100 #define GMUX_INTERRUPT_STATUS_POWER     (1 << 2)
101 #define GMUX_INTERRUPT_STATUS_HOTPLUG   (1 << 3)
102 
103 #define GMUX_BRIGHTNESS_MASK            0x00ffffff
104 #define GMUX_MAX_BRIGHTNESS             GMUX_BRIGHTNESS_MASK
105 
106 static u8 gmux_pio_read8(struct apple_gmux_data *gmux_data, int port)
107 {
108         return inb(gmux_data->iostart + port);
109 }
110 
111 static void gmux_pio_write8(struct apple_gmux_data *gmux_data, int port,
112                                u8 val)
113 {
114         outb(val, gmux_data->iostart + port);
115 }
116 
117 static u32 gmux_pio_read32(struct apple_gmux_data *gmux_data, int port)
118 {
119         return inl(gmux_data->iostart + port);
120 }
121 
122 static void gmux_pio_write32(struct apple_gmux_data *gmux_data, int port,
123                              u32 val)
124 {
125         int i;
126         u8 tmpval;
127 
128         for (i = 0; i < 4; i++) {
129                 tmpval = (val >> (i * 8)) & 0xff;
130                 outb(tmpval, gmux_data->iostart + port + i);
131         }
132 }
133 
134 static int gmux_index_wait_ready(struct apple_gmux_data *gmux_data)
135 {
136         int i = 200;
137         u8 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
138 
139         while (i && (gwr & 0x01)) {
140                 inb(gmux_data->iostart + GMUX_PORT_READ);
141                 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
142                 udelay(100);
143                 i--;
144         }
145 
146         return !!i;
147 }
148 
149 static int gmux_index_wait_complete(struct apple_gmux_data *gmux_data)
150 {
151         int i = 200;
152         u8 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
153 
154         while (i && !(gwr & 0x01)) {
155                 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
156                 udelay(100);
157                 i--;
158         }
159 
160         if (gwr & 0x01)
161                 inb(gmux_data->iostart + GMUX_PORT_READ);
162 
163         return !!i;
164 }
165 
166 static u8 gmux_index_read8(struct apple_gmux_data *gmux_data, int port)
167 {
168         u8 val;
169 
170         mutex_lock(&gmux_data->index_lock);
171         gmux_index_wait_ready(gmux_data);
172         outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
173         gmux_index_wait_complete(gmux_data);
174         val = inb(gmux_data->iostart + GMUX_PORT_VALUE);
175         mutex_unlock(&gmux_data->index_lock);
176 
177         return val;
178 }
179 
180 static void gmux_index_write8(struct apple_gmux_data *gmux_data, int port,
181                               u8 val)
182 {
183         mutex_lock(&gmux_data->index_lock);
184         outb(val, gmux_data->iostart + GMUX_PORT_VALUE);
185         gmux_index_wait_ready(gmux_data);
186         outb(port & 0xff, gmux_data->iostart + GMUX_PORT_WRITE);
187         gmux_index_wait_complete(gmux_data);
188         mutex_unlock(&gmux_data->index_lock);
189 }
190 
191 static u32 gmux_index_read32(struct apple_gmux_data *gmux_data, int port)
192 {
193         u32 val;
194 
195         mutex_lock(&gmux_data->index_lock);
196         gmux_index_wait_ready(gmux_data);
197         outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
198         gmux_index_wait_complete(gmux_data);
199         val = inl(gmux_data->iostart + GMUX_PORT_VALUE);
200         mutex_unlock(&gmux_data->index_lock);
201 
202         return val;
203 }
204 
205 static void gmux_index_write32(struct apple_gmux_data *gmux_data, int port,
206                                u32 val)
207 {
208         int i;
209         u8 tmpval;
210 
211         mutex_lock(&gmux_data->index_lock);
212 
213         for (i = 0; i < 4; i++) {
214                 tmpval = (val >> (i * 8)) & 0xff;
215                 outb(tmpval, gmux_data->iostart + GMUX_PORT_VALUE + i);
216         }
217 
218         gmux_index_wait_ready(gmux_data);
219         outb(port & 0xff, gmux_data->iostart + GMUX_PORT_WRITE);
220         gmux_index_wait_complete(gmux_data);
221         mutex_unlock(&gmux_data->index_lock);
222 }
223 
224 static u8 gmux_read8(struct apple_gmux_data *gmux_data, int port)
225 {
226         if (gmux_data->indexed)
227                 return gmux_index_read8(gmux_data, port);
228         else
229                 return gmux_pio_read8(gmux_data, port);
230 }
231 
232 static void gmux_write8(struct apple_gmux_data *gmux_data, int port, u8 val)
233 {
234         if (gmux_data->indexed)
235                 gmux_index_write8(gmux_data, port, val);
236         else
237                 gmux_pio_write8(gmux_data, port, val);
238 }
239 
240 static u32 gmux_read32(struct apple_gmux_data *gmux_data, int port)
241 {
242         if (gmux_data->indexed)
243                 return gmux_index_read32(gmux_data, port);
244         else
245                 return gmux_pio_read32(gmux_data, port);
246 }
247 
248 static void gmux_write32(struct apple_gmux_data *gmux_data, int port,
249                              u32 val)
250 {
251         if (gmux_data->indexed)
252                 gmux_index_write32(gmux_data, port, val);
253         else
254                 gmux_pio_write32(gmux_data, port, val);
255 }
256 
257 static bool gmux_is_indexed(struct apple_gmux_data *gmux_data)
258 {
259         u16 val;
260 
261         outb(0xaa, gmux_data->iostart + 0xcc);
262         outb(0x55, gmux_data->iostart + 0xcd);
263         outb(0x00, gmux_data->iostart + 0xce);
264 
265         val = inb(gmux_data->iostart + 0xcc) |
266                 (inb(gmux_data->iostart + 0xcd) << 8);
267 
268         if (val == 0x55aa)
269                 return true;
270 
271         return false;
272 }
273 
274 /**
275  * DOC: Backlight control
276  *
277  * On single GPU MacBooks, the PWM signal for the backlight is generated by
278  * the GPU. On dual GPU MacBook Pros by contrast, either GPU may be suspended
279  * to conserve energy. Hence the PWM signal needs to be generated by a separate
280  * backlight driver which is controlled by gmux. The earliest generation
281  * MBP5 2008/09 uses a `TI LP8543`_ backlight driver. All newer models
282  * use a `TI LP8545`_.
283  *
284  * .. _TI LP8543: http://www.ti.com/lit/ds/symlink/lp8543.pdf
285  * .. _TI LP8545: http://www.ti.com/lit/ds/symlink/lp8545.pdf
286  */
287 
288 static int gmux_get_brightness(struct backlight_device *bd)
289 {
290         struct apple_gmux_data *gmux_data = bl_get_data(bd);
291         return gmux_read32(gmux_data, GMUX_PORT_BRIGHTNESS) &
292                GMUX_BRIGHTNESS_MASK;
293 }
294 
295 static int gmux_update_status(struct backlight_device *bd)
296 {
297         struct apple_gmux_data *gmux_data = bl_get_data(bd);
298         u32 brightness = bd->props.brightness;
299 
300         if (bd->props.state & BL_CORE_SUSPENDED)
301                 return 0;
302 
303         gmux_write32(gmux_data, GMUX_PORT_BRIGHTNESS, brightness);
304 
305         return 0;
306 }
307 
308 static const struct backlight_ops gmux_bl_ops = {
309         .options = BL_CORE_SUSPENDRESUME,
310         .get_brightness = gmux_get_brightness,
311         .update_status = gmux_update_status,
312 };
313 
314 /**
315  * DOC: Graphics mux
316  *
317  * On pre-retinas, the LVDS outputs of both GPUs feed into gmux which muxes
318  * either of them to the panel. One of the tricks gmux has up its sleeve is
319  * to lengthen the blanking interval of its output during a switch to
320  * synchronize it with the GPU switched to. This allows for a flicker-free
321  * switch that is imperceptible by the user (`US 8,687,007 B2`_).
322  *
323  * On retinas, muxing is no longer done by gmux itself, but by a separate
324  * chip which is controlled by gmux. The chip is triple sourced, it is
325  * either an `NXP CBTL06142`_, `TI HD3SS212`_ or `Pericom PI3VDP12412`_.
326  * The panel is driven with eDP instead of LVDS since the pixel clock
327  * required for retina resolution exceeds LVDS' limits.
328  *
329  * Pre-retinas are able to switch the panel's DDC pins separately.
330  * This is handled by a `TI SN74LV4066A`_ which is controlled by gmux.
331  * The inactive GPU can thus probe the panel's EDID without switching over
332  * the entire panel. Retinas lack this functionality as the chips used for
333  * eDP muxing are incapable of switching the AUX channel separately (see
334  * the linked data sheets, Pericom would be capable but this is unused).
335  * However the retina panel has the NO_AUX_HANDSHAKE_LINK_TRAINING bit set
336  * in its DPCD, allowing the inactive GPU to skip the AUX handshake and
337  * set up the output with link parameters pre-calibrated by the active GPU.
338  *
339  * The external DP port is only fully switchable on the first two unibody
340  * MacBook Pro generations, MBP5 2008/09 and MBP6 2010. This is done by an
341  * `NXP CBTL06141`_ which is controlled by gmux. It's the predecessor of the
342  * eDP mux on retinas, the difference being support for 2.7 versus 5.4 Gbit/s.
343  *
344  * The following MacBook Pro generations replaced the external DP port with a
345  * combined DP/Thunderbolt port and lost the ability to switch it between GPUs,
346  * connecting it either to the discrete GPU or the Thunderbolt controller.
347  * Oddly enough, while the full port is no longer switchable, AUX and HPD
348  * are still switchable by way of an `NXP CBTL03062`_ (on pre-retinas
349  * MBP8 2011 and MBP9 2012) or two `TI TS3DS10224`_ (on retinas) under the
350  * control of gmux. Since the integrated GPU is missing the main link,
351  * external displays appear to it as phantoms which fail to link-train.
352  *
353  * gmux receives the HPD signal of all display connectors and sends an
354  * interrupt on hotplug. On generations which cannot switch external ports,
355  * the discrete GPU can then be woken to drive the newly connected display.
356  * The ability to switch AUX on these generations could be used to improve
357  * reliability of hotplug detection by having the integrated GPU poll the
358  * ports while the discrete GPU is asleep, but currently we do not make use
359  * of this feature.
360  *
361  * gmux' initial switch state on bootup is user configurable via the EFI
362  * variable ``gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9`` (5th byte,
363  * 1 = IGD, 0 = DIS). Based on this setting, the EFI firmware tells gmux to
364  * switch the panel and the external DP connector and allocates a framebuffer
365  * for the selected GPU.
366  *
367  * .. _US 8,687,007 B2: http://pimg-fpiw.uspto.gov/fdd/07/870/086/0.pdf
368  * .. _NXP CBTL06141:   http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
369  * .. _NXP CBTL06142:   http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
370  * .. _TI HD3SS212:     http://www.ti.com/lit/ds/symlink/hd3ss212.pdf
371  * .. _Pericom PI3VDP12412: https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf
372  * .. _TI SN74LV4066A:  http://www.ti.com/lit/ds/symlink/sn74lv4066a.pdf
373  * .. _NXP CBTL03062:   http://pdf.datasheetarchive.com/indexerfiles/Datasheets-SW16/DSASW00308511.pdf
374  * .. _TI TS3DS10224:   http://www.ti.com/lit/ds/symlink/ts3ds10224.pdf
375  */
376 
377 static void gmux_read_switch_state(struct apple_gmux_data *gmux_data)
378 {
379         if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_DDC) == 1)
380                 gmux_data->switch_state_ddc = VGA_SWITCHEROO_IGD;
381         else
382                 gmux_data->switch_state_ddc = VGA_SWITCHEROO_DIS;
383 
384         if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_DISPLAY) == 2)
385                 gmux_data->switch_state_display = VGA_SWITCHEROO_IGD;
386         else
387                 gmux_data->switch_state_display = VGA_SWITCHEROO_DIS;
388 
389         if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL) == 2)
390                 gmux_data->switch_state_external = VGA_SWITCHEROO_IGD;
391         else
392                 gmux_data->switch_state_external = VGA_SWITCHEROO_DIS;
393 }
394 
395 static void gmux_write_switch_state(struct apple_gmux_data *gmux_data)
396 {
397         if (gmux_data->switch_state_ddc == VGA_SWITCHEROO_IGD)
398                 gmux_write8(gmux_data, GMUX_PORT_SWITCH_DDC, 1);
399         else
400                 gmux_write8(gmux_data, GMUX_PORT_SWITCH_DDC, 2);
401 
402         if (gmux_data->switch_state_display == VGA_SWITCHEROO_IGD)
403                 gmux_write8(gmux_data, GMUX_PORT_SWITCH_DISPLAY, 2);
404         else
405                 gmux_write8(gmux_data, GMUX_PORT_SWITCH_DISPLAY, 3);
406 
407         if (gmux_data->switch_state_external == VGA_SWITCHEROO_IGD)
408                 gmux_write8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 2);
409         else
410                 gmux_write8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 3);
411 }
412 
413 static int gmux_switchto(enum vga_switcheroo_client_id id)
414 {
415         apple_gmux_data->switch_state_ddc = id;
416         apple_gmux_data->switch_state_display = id;
417         apple_gmux_data->switch_state_external = id;
418 
419         gmux_write_switch_state(apple_gmux_data);
420 
421         return 0;
422 }
423 
424 static int gmux_switch_ddc(enum vga_switcheroo_client_id id)
425 {
426         enum vga_switcheroo_client_id old_ddc_owner =
427                 apple_gmux_data->switch_state_ddc;
428 
429         if (id == old_ddc_owner)
430                 return id;
431 
432         pr_debug("Switching DDC from %d to %d\n", old_ddc_owner, id);
433         apple_gmux_data->switch_state_ddc = id;
434 
435         if (id == VGA_SWITCHEROO_IGD)
436                 gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1);
437         else
438                 gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2);
439 
440         return old_ddc_owner;
441 }
442 
443 /**
444  * DOC: Power control
445  *
446  * gmux is able to cut power to the discrete GPU. It automatically takes care
447  * of the correct sequence to tear down and bring up the power rails for
448  * core voltage, VRAM and PCIe.
449  */
450 
451 static int gmux_set_discrete_state(struct apple_gmux_data *gmux_data,
452                                    enum vga_switcheroo_state state)
453 {
454         reinit_completion(&gmux_data->powerchange_done);
455 
456         if (state == VGA_SWITCHEROO_ON) {
457                 gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 1);
458                 gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 3);
459                 pr_debug("Discrete card powered up\n");
460         } else {
461                 gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 1);
462                 gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 0);
463                 pr_debug("Discrete card powered down\n");
464         }
465 
466         gmux_data->power_state = state;
467 
468         if (gmux_data->gpe >= 0 &&
469             !wait_for_completion_interruptible_timeout(&gmux_data->powerchange_done,
470                                                        msecs_to_jiffies(200)))
471                 pr_warn("Timeout waiting for gmux switch to complete\n");
472 
473         return 0;
474 }
475 
476 static int gmux_set_power_state(enum vga_switcheroo_client_id id,
477                                 enum vga_switcheroo_state state)
478 {
479         if (id == VGA_SWITCHEROO_IGD)
480                 return 0;
481 
482         return gmux_set_discrete_state(apple_gmux_data, state);
483 }
484 
485 static int gmux_get_client_id(struct pci_dev *pdev)
486 {
487         /*
488          * Early Macbook Pros with switchable graphics use nvidia
489          * integrated graphics. Hardcode that the 9400M is integrated.
490          */
491         if (pdev->vendor == PCI_VENDOR_ID_INTEL)
492                 return VGA_SWITCHEROO_IGD;
493         else if (pdev->vendor == PCI_VENDOR_ID_NVIDIA &&
494                  pdev->device == 0x0863)
495                 return VGA_SWITCHEROO_IGD;
496         else
497                 return VGA_SWITCHEROO_DIS;
498 }
499 
500 static const struct vga_switcheroo_handler gmux_handler_indexed = {
501         .switchto = gmux_switchto,
502         .power_state = gmux_set_power_state,
503         .get_client_id = gmux_get_client_id,
504 };
505 
506 static const struct vga_switcheroo_handler gmux_handler_classic = {
507         .switchto = gmux_switchto,
508         .switch_ddc = gmux_switch_ddc,
509         .power_state = gmux_set_power_state,
510         .get_client_id = gmux_get_client_id,
511 };
512 
513 /**
514  * DOC: Interrupt
515  *
516  * gmux is also connected to a GPIO pin of the southbridge and thereby is able
517  * to trigger an ACPI GPE. On the MBP5 2008/09 it's GPIO pin 22 of the Nvidia
518  * MCP79, on all following generations it's GPIO pin 6 of the Intel PCH.
519  * The GPE merely signals that an interrupt occurred, the actual type of event
520  * is identified by reading a gmux register.
521  */
522 
523 static inline void gmux_disable_interrupts(struct apple_gmux_data *gmux_data)
524 {
525         gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
526                     GMUX_INTERRUPT_DISABLE);
527 }
528 
529 static inline void gmux_enable_interrupts(struct apple_gmux_data *gmux_data)
530 {
531         gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
532                     GMUX_INTERRUPT_ENABLE);
533 }
534 
535 static inline u8 gmux_interrupt_get_status(struct apple_gmux_data *gmux_data)
536 {
537         return gmux_read8(gmux_data, GMUX_PORT_INTERRUPT_STATUS);
538 }
539 
540 static void gmux_clear_interrupts(struct apple_gmux_data *gmux_data)
541 {
542         u8 status;
543 
544         /* to clear interrupts write back current status */
545         status = gmux_interrupt_get_status(gmux_data);
546         gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_STATUS, status);
547 }
548 
549 static void gmux_notify_handler(acpi_handle device, u32 value, void *context)
550 {
551         u8 status;
552         struct pnp_dev *pnp = (struct pnp_dev *)context;
553         struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
554 
555         status = gmux_interrupt_get_status(gmux_data);
556         gmux_disable_interrupts(gmux_data);
557         pr_debug("Notify handler called: status %d\n", status);
558 
559         gmux_clear_interrupts(gmux_data);
560         gmux_enable_interrupts(gmux_data);
561 
562         if (status & GMUX_INTERRUPT_STATUS_POWER)
563                 complete(&gmux_data->powerchange_done);
564 }
565 
566 static int gmux_suspend(struct device *dev)
567 {
568         struct pnp_dev *pnp = to_pnp_dev(dev);
569         struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
570 
571         gmux_disable_interrupts(gmux_data);
572         return 0;
573 }
574 
575 static int gmux_resume(struct device *dev)
576 {
577         struct pnp_dev *pnp = to_pnp_dev(dev);
578         struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
579 
580         gmux_enable_interrupts(gmux_data);
581         gmux_write_switch_state(gmux_data);
582         if (gmux_data->power_state == VGA_SWITCHEROO_OFF)
583                 gmux_set_discrete_state(gmux_data, gmux_data->power_state);
584         return 0;
585 }
586 
587 static struct pci_dev *gmux_get_io_pdev(void)
588 {
589         struct pci_dev *pdev = NULL;
590 
591         while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev))) {
592                 u16 cmd;
593 
594                 pci_read_config_word(pdev, PCI_COMMAND, &cmd);
595                 if (!(cmd & PCI_COMMAND_IO))
596                         continue;
597 
598                 return pdev;
599         }
600 
601         return NULL;
602 }
603 
604 static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
605 {
606         struct apple_gmux_data *gmux_data;
607         struct resource *res;
608         struct backlight_properties props;
609         struct backlight_device *bdev;
610         u8 ver_major, ver_minor, ver_release;
611         int ret = -ENXIO;
612         acpi_status status;
613         unsigned long long gpe;
614         struct pci_dev *pdev = NULL;
615 
616         if (apple_gmux_data)
617                 return -EBUSY;
618 
619         gmux_data = kzalloc(sizeof(*gmux_data), GFP_KERNEL);
620         if (!gmux_data)
621                 return -ENOMEM;
622         pnp_set_drvdata(pnp, gmux_data);
623 
624         res = pnp_get_resource(pnp, IORESOURCE_IO, 0);
625         if (!res) {
626                 pr_err("Failed to find gmux I/O resource\n");
627                 goto err_free;
628         }
629 
630         gmux_data->iostart = res->start;
631         gmux_data->iolen = res->end - res->start;
632 
633         if (gmux_data->iolen < GMUX_MIN_IO_LEN) {
634                 pr_err("gmux I/O region too small (%lu < %u)\n",
635                        gmux_data->iolen, GMUX_MIN_IO_LEN);
636                 goto err_free;
637         }
638 
639         if (!request_region(gmux_data->iostart, gmux_data->iolen,
640                             "Apple gmux")) {
641                 pr_err("gmux I/O already in use\n");
642                 goto err_free;
643         }
644 
645         /*
646          * Invalid version information may indicate either that the gmux
647          * device isn't present or that it's a new one that uses indexed
648          * io
649          */
650 
651         ver_major = gmux_read8(gmux_data, GMUX_PORT_VERSION_MAJOR);
652         ver_minor = gmux_read8(gmux_data, GMUX_PORT_VERSION_MINOR);
653         ver_release = gmux_read8(gmux_data, GMUX_PORT_VERSION_RELEASE);
654         if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
655                 if (gmux_is_indexed(gmux_data)) {
656                         u32 version;
657                         mutex_init(&gmux_data->index_lock);
658                         gmux_data->indexed = true;
659                         version = gmux_read32(gmux_data,
660                                 GMUX_PORT_VERSION_MAJOR);
661                         ver_major = (version >> 24) & 0xff;
662                         ver_minor = (version >> 16) & 0xff;
663                         ver_release = (version >> 8) & 0xff;
664                 } else {
665                         pr_info("gmux device not present or IO disabled\n");
666                         ret = -ENODEV;
667                         goto err_release;
668                 }
669         }
670         pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor,
671                 ver_release, (gmux_data->indexed ? "indexed" : "classic"));
672 
673         /*
674          * Apple systems with gmux are EFI based and normally don't use
675          * VGA. In addition changing IO+MEM ownership between IGP and dGPU
676          * disables IO/MEM used for backlight control on some systems.
677          * Lock IO+MEM to GPU with active IO to prevent switch.
678          */
679         pdev = gmux_get_io_pdev();
680         if (pdev && vga_tryget(pdev,
681                                VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM)) {
682                 pr_err("IO+MEM vgaarb-locking for PCI:%s failed\n",
683                         pci_name(pdev));
684                 ret = -EBUSY;
685                 goto err_release;
686         } else if (pdev)
687                 pr_info("locked IO for PCI:%s\n", pci_name(pdev));
688         gmux_data->pdev = pdev;
689 
690         memset(&props, 0, sizeof(props));
691         props.type = BACKLIGHT_PLATFORM;
692         props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);
693 
694         /*
695          * Currently it's assumed that the maximum brightness is less than
696          * 2^24 for compatibility with old gmux versions. Cap the max
697          * brightness at this value, but print a warning if the hardware
698          * reports something higher so that it can be fixed.
699          */
700         if (WARN_ON(props.max_brightness > GMUX_MAX_BRIGHTNESS))
701                 props.max_brightness = GMUX_MAX_BRIGHTNESS;
702 
703         bdev = backlight_device_register("gmux_backlight", &pnp->dev,
704                                          gmux_data, &gmux_bl_ops, &props);
705         if (IS_ERR(bdev)) {
706                 ret = PTR_ERR(bdev);
707                 goto err_release;
708         }
709 
710         gmux_data->bdev = bdev;
711         bdev->props.brightness = gmux_get_brightness(bdev);
712         backlight_update_status(bdev);
713 
714         /*
715          * The backlight situation on Macs is complicated. If the gmux is
716          * present it's the best choice, because it always works for
717          * backlight control and supports more levels than other options.
718          * Disable the other backlight choices.
719          */
720         acpi_video_set_dmi_backlight_type(acpi_backlight_vendor);
721         apple_bl_unregister();
722 
723         gmux_data->power_state = VGA_SWITCHEROO_ON;
724 
725         gmux_data->dhandle = ACPI_HANDLE(&pnp->dev);
726         if (!gmux_data->dhandle) {
727                 pr_err("Cannot find acpi handle for pnp device %s\n",
728                        dev_name(&pnp->dev));
729                 ret = -ENODEV;
730                 goto err_notify;
731         }
732 
733         status = acpi_evaluate_integer(gmux_data->dhandle, "GMGP", NULL, &gpe);
734         if (ACPI_SUCCESS(status)) {
735                 gmux_data->gpe = (int)gpe;
736 
737                 status = acpi_install_notify_handler(gmux_data->dhandle,
738                                                      ACPI_DEVICE_NOTIFY,
739                                                      &gmux_notify_handler, pnp);
740                 if (ACPI_FAILURE(status)) {
741                         pr_err("Install notify handler failed: %s\n",
742                                acpi_format_exception(status));
743                         ret = -ENODEV;
744                         goto err_notify;
745                 }
746 
747                 status = acpi_enable_gpe(NULL, gmux_data->gpe);
748                 if (ACPI_FAILURE(status)) {
749                         pr_err("Cannot enable gpe: %s\n",
750                                acpi_format_exception(status));
751                         goto err_enable_gpe;
752                 }
753         } else {
754                 pr_warn("No GPE found for gmux\n");
755                 gmux_data->gpe = -1;
756         }
757 
758         apple_gmux_data = gmux_data;
759         init_completion(&gmux_data->powerchange_done);
760         gmux_enable_interrupts(gmux_data);
761         gmux_read_switch_state(gmux_data);
762 
763         /*
764          * Retina MacBook Pros cannot switch the panel's AUX separately
765          * and need eDP pre-calibration. They are distinguishable from
766          * pre-retinas by having an "indexed" gmux.
767          *
768          * Pre-retina MacBook Pros can switch the panel's DDC separately.
769          */
770         if (gmux_data->indexed)
771                 ret = vga_switcheroo_register_handler(&gmux_handler_indexed,
772                                               VGA_SWITCHEROO_NEEDS_EDP_CONFIG);
773         else
774                 ret = vga_switcheroo_register_handler(&gmux_handler_classic,
775                                               VGA_SWITCHEROO_CAN_SWITCH_DDC);
776         if (ret) {
777                 pr_err("Failed to register vga_switcheroo handler\n");
778                 goto err_register_handler;
779         }
780 
781         return 0;
782 
783 err_register_handler:
784         gmux_disable_interrupts(gmux_data);
785         apple_gmux_data = NULL;
786         if (gmux_data->gpe >= 0)
787                 acpi_disable_gpe(NULL, gmux_data->gpe);
788 err_enable_gpe:
789         if (gmux_data->gpe >= 0)
790                 acpi_remove_notify_handler(gmux_data->dhandle,
791                                            ACPI_DEVICE_NOTIFY,
792                                            &gmux_notify_handler);
793 err_notify:
794         backlight_device_unregister(bdev);
795 err_release:
796         if (gmux_data->pdev)
797                 vga_put(gmux_data->pdev,
798                         VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
799         pci_dev_put(pdev);
800         release_region(gmux_data->iostart, gmux_data->iolen);
801 err_free:
802         kfree(gmux_data);
803         return ret;
804 }
805 
806 static void gmux_remove(struct pnp_dev *pnp)
807 {
808         struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
809 
810         vga_switcheroo_unregister_handler();
811         gmux_disable_interrupts(gmux_data);
812         if (gmux_data->gpe >= 0) {
813                 acpi_disable_gpe(NULL, gmux_data->gpe);
814                 acpi_remove_notify_handler(gmux_data->dhandle,
815                                            ACPI_DEVICE_NOTIFY,
816                                            &gmux_notify_handler);
817         }
818 
819         if (gmux_data->pdev) {
820                 vga_put(gmux_data->pdev,
821                         VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM);
822                 pci_dev_put(gmux_data->pdev);
823         }
824         backlight_device_unregister(gmux_data->bdev);
825 
826         release_region(gmux_data->iostart, gmux_data->iolen);
827         apple_gmux_data = NULL;
828         kfree(gmux_data);
829 
830         acpi_video_register();
831         apple_bl_register();
832 }
833 
834 static const struct pnp_device_id gmux_device_ids[] = {
835         {GMUX_ACPI_HID, 0},
836         {"", 0}
837 };
838 
839 static const struct dev_pm_ops gmux_dev_pm_ops = {
840         .suspend = gmux_suspend,
841         .resume = gmux_resume,
842 };
843 
844 static struct pnp_driver gmux_pnp_driver = {
845         .name           = "apple-gmux",
846         .probe          = gmux_probe,
847         .remove         = gmux_remove,
848         .id_table       = gmux_device_ids,
849         .driver         = {
850                         .pm = &gmux_dev_pm_ops,
851         },
852 };
853 
854 module_pnp_driver(gmux_pnp_driver);
855 MODULE_AUTHOR("Seth Forshee <seth.forshee@canonical.com>");
856 MODULE_DESCRIPTION("Apple Gmux Driver");
857 MODULE_LICENSE("GPL");
858 MODULE_DEVICE_TABLE(pnp, gmux_device_ids);
859 

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