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0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  *  Gmux driver for Apple laptops
0004  *
0005  *  Copyright (C) Canonical Ltd. <seth.forshee@canonical.com>
0006  *  Copyright (C) 2010-2012 Andreas Heider <andreas@meetr.de>
0007  *  Copyright (C) 2015 Lukas Wunner <lukas@wunner.de>
0008  */
0009 
0010 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0011 
0012 #include <linux/module.h>
0013 #include <linux/kernel.h>
0014 #include <linux/init.h>
0015 #include <linux/backlight.h>
0016 #include <linux/acpi.h>
0017 #include <linux/pnp.h>
0018 #include <linux/apple_bl.h>
0019 #include <linux/apple-gmux.h>
0020 #include <linux/slab.h>
0021 #include <linux/delay.h>
0022 #include <linux/pci.h>
0023 #include <linux/vga_switcheroo.h>
0024 #include <acpi/video.h>
0025 #include <asm/io.h>
0026 
0027 /**
0028  * DOC: Overview
0029  *
0030  * gmux is a microcontroller built into the MacBook Pro to support dual GPUs:
0031  * A `Lattice XP2`_ on pre-retinas, a `Renesas R4F2113`_ on retinas.
0032  *
0033  * (The MacPro6,1 2013 also has a gmux, however it is unclear why since it has
0034  * dual GPUs but no built-in display.)
0035  *
0036  * gmux is connected to the LPC bus of the southbridge. Its I/O ports are
0037  * accessed differently depending on the microcontroller: Driver functions
0038  * to access a pre-retina gmux are infixed ``_pio_``, those for a retina gmux
0039  * are infixed ``_index_``.
0040  *
0041  * .. _Lattice XP2:
0042  *     http://www.latticesemi.com/en/Products/FPGAandCPLD/LatticeXP2.aspx
0043  * .. _Renesas R4F2113:
0044  *     http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp
0045  */
0046 
0047 struct apple_gmux_data {
0048     unsigned long iostart;
0049     unsigned long iolen;
0050     bool indexed;
0051     struct mutex index_lock;
0052 
0053     struct backlight_device *bdev;
0054 
0055     /* switcheroo data */
0056     acpi_handle dhandle;
0057     int gpe;
0058     bool external_switchable;
0059     enum vga_switcheroo_client_id switch_state_display;
0060     enum vga_switcheroo_client_id switch_state_ddc;
0061     enum vga_switcheroo_client_id switch_state_external;
0062     enum vga_switcheroo_state power_state;
0063     struct completion powerchange_done;
0064 };
0065 
0066 static struct apple_gmux_data *apple_gmux_data;
0067 
0068 /*
0069  * gmux port offsets. Many of these are not yet used, but may be in the
0070  * future, and it's useful to have them documented here anyhow.
0071  */
0072 #define GMUX_PORT_VERSION_MAJOR     0x04
0073 #define GMUX_PORT_VERSION_MINOR     0x05
0074 #define GMUX_PORT_VERSION_RELEASE   0x06
0075 #define GMUX_PORT_SWITCH_DISPLAY    0x10
0076 #define GMUX_PORT_SWITCH_GET_DISPLAY    0x11
0077 #define GMUX_PORT_INTERRUPT_ENABLE  0x14
0078 #define GMUX_PORT_INTERRUPT_STATUS  0x16
0079 #define GMUX_PORT_SWITCH_DDC        0x28
0080 #define GMUX_PORT_SWITCH_EXTERNAL   0x40
0081 #define GMUX_PORT_SWITCH_GET_EXTERNAL   0x41
0082 #define GMUX_PORT_DISCRETE_POWER    0x50
0083 #define GMUX_PORT_MAX_BRIGHTNESS    0x70
0084 #define GMUX_PORT_BRIGHTNESS        0x74
0085 #define GMUX_PORT_VALUE         0xc2
0086 #define GMUX_PORT_READ          0xd0
0087 #define GMUX_PORT_WRITE         0xd4
0088 
0089 #define GMUX_MIN_IO_LEN         (GMUX_PORT_BRIGHTNESS + 4)
0090 
0091 #define GMUX_INTERRUPT_ENABLE       0xff
0092 #define GMUX_INTERRUPT_DISABLE      0x00
0093 
0094 #define GMUX_INTERRUPT_STATUS_ACTIVE    0
0095 #define GMUX_INTERRUPT_STATUS_DISPLAY   (1 << 0)
0096 #define GMUX_INTERRUPT_STATUS_POWER (1 << 2)
0097 #define GMUX_INTERRUPT_STATUS_HOTPLUG   (1 << 3)
0098 
0099 #define GMUX_BRIGHTNESS_MASK        0x00ffffff
0100 #define GMUX_MAX_BRIGHTNESS     GMUX_BRIGHTNESS_MASK
0101 
0102 static u8 gmux_pio_read8(struct apple_gmux_data *gmux_data, int port)
0103 {
0104     return inb(gmux_data->iostart + port);
0105 }
0106 
0107 static void gmux_pio_write8(struct apple_gmux_data *gmux_data, int port,
0108                    u8 val)
0109 {
0110     outb(val, gmux_data->iostart + port);
0111 }
0112 
0113 static u32 gmux_pio_read32(struct apple_gmux_data *gmux_data, int port)
0114 {
0115     return inl(gmux_data->iostart + port);
0116 }
0117 
0118 static void gmux_pio_write32(struct apple_gmux_data *gmux_data, int port,
0119                  u32 val)
0120 {
0121     int i;
0122     u8 tmpval;
0123 
0124     for (i = 0; i < 4; i++) {
0125         tmpval = (val >> (i * 8)) & 0xff;
0126         outb(tmpval, gmux_data->iostart + port + i);
0127     }
0128 }
0129 
0130 static int gmux_index_wait_ready(struct apple_gmux_data *gmux_data)
0131 {
0132     int i = 200;
0133     u8 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
0134 
0135     while (i && (gwr & 0x01)) {
0136         inb(gmux_data->iostart + GMUX_PORT_READ);
0137         gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
0138         udelay(100);
0139         i--;
0140     }
0141 
0142     return !!i;
0143 }
0144 
0145 static int gmux_index_wait_complete(struct apple_gmux_data *gmux_data)
0146 {
0147     int i = 200;
0148     u8 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
0149 
0150     while (i && !(gwr & 0x01)) {
0151         gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
0152         udelay(100);
0153         i--;
0154     }
0155 
0156     if (gwr & 0x01)
0157         inb(gmux_data->iostart + GMUX_PORT_READ);
0158 
0159     return !!i;
0160 }
0161 
0162 static u8 gmux_index_read8(struct apple_gmux_data *gmux_data, int port)
0163 {
0164     u8 val;
0165 
0166     mutex_lock(&gmux_data->index_lock);
0167     gmux_index_wait_ready(gmux_data);
0168     outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
0169     gmux_index_wait_complete(gmux_data);
0170     val = inb(gmux_data->iostart + GMUX_PORT_VALUE);
0171     mutex_unlock(&gmux_data->index_lock);
0172 
0173     return val;
0174 }
0175 
0176 static void gmux_index_write8(struct apple_gmux_data *gmux_data, int port,
0177                   u8 val)
0178 {
0179     mutex_lock(&gmux_data->index_lock);
0180     outb(val, gmux_data->iostart + GMUX_PORT_VALUE);
0181     gmux_index_wait_ready(gmux_data);
0182     outb(port & 0xff, gmux_data->iostart + GMUX_PORT_WRITE);
0183     gmux_index_wait_complete(gmux_data);
0184     mutex_unlock(&gmux_data->index_lock);
0185 }
0186 
0187 static u32 gmux_index_read32(struct apple_gmux_data *gmux_data, int port)
0188 {
0189     u32 val;
0190 
0191     mutex_lock(&gmux_data->index_lock);
0192     gmux_index_wait_ready(gmux_data);
0193     outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
0194     gmux_index_wait_complete(gmux_data);
0195     val = inl(gmux_data->iostart + GMUX_PORT_VALUE);
0196     mutex_unlock(&gmux_data->index_lock);
0197 
0198     return val;
0199 }
0200 
0201 static void gmux_index_write32(struct apple_gmux_data *gmux_data, int port,
0202                    u32 val)
0203 {
0204     int i;
0205     u8 tmpval;
0206 
0207     mutex_lock(&gmux_data->index_lock);
0208 
0209     for (i = 0; i < 4; i++) {
0210         tmpval = (val >> (i * 8)) & 0xff;
0211         outb(tmpval, gmux_data->iostart + GMUX_PORT_VALUE + i);
0212     }
0213 
0214     gmux_index_wait_ready(gmux_data);
0215     outb(port & 0xff, gmux_data->iostart + GMUX_PORT_WRITE);
0216     gmux_index_wait_complete(gmux_data);
0217     mutex_unlock(&gmux_data->index_lock);
0218 }
0219 
0220 static u8 gmux_read8(struct apple_gmux_data *gmux_data, int port)
0221 {
0222     if (gmux_data->indexed)
0223         return gmux_index_read8(gmux_data, port);
0224     else
0225         return gmux_pio_read8(gmux_data, port);
0226 }
0227 
0228 static void gmux_write8(struct apple_gmux_data *gmux_data, int port, u8 val)
0229 {
0230     if (gmux_data->indexed)
0231         gmux_index_write8(gmux_data, port, val);
0232     else
0233         gmux_pio_write8(gmux_data, port, val);
0234 }
0235 
0236 static u32 gmux_read32(struct apple_gmux_data *gmux_data, int port)
0237 {
0238     if (gmux_data->indexed)
0239         return gmux_index_read32(gmux_data, port);
0240     else
0241         return gmux_pio_read32(gmux_data, port);
0242 }
0243 
0244 static void gmux_write32(struct apple_gmux_data *gmux_data, int port,
0245                  u32 val)
0246 {
0247     if (gmux_data->indexed)
0248         gmux_index_write32(gmux_data, port, val);
0249     else
0250         gmux_pio_write32(gmux_data, port, val);
0251 }
0252 
0253 static bool gmux_is_indexed(struct apple_gmux_data *gmux_data)
0254 {
0255     u16 val;
0256 
0257     outb(0xaa, gmux_data->iostart + 0xcc);
0258     outb(0x55, gmux_data->iostart + 0xcd);
0259     outb(0x00, gmux_data->iostart + 0xce);
0260 
0261     val = inb(gmux_data->iostart + 0xcc) |
0262         (inb(gmux_data->iostart + 0xcd) << 8);
0263 
0264     if (val == 0x55aa)
0265         return true;
0266 
0267     return false;
0268 }
0269 
0270 /**
0271  * DOC: Backlight control
0272  *
0273  * On single GPU MacBooks, the PWM signal for the backlight is generated by
0274  * the GPU. On dual GPU MacBook Pros by contrast, either GPU may be suspended
0275  * to conserve energy. Hence the PWM signal needs to be generated by a separate
0276  * backlight driver which is controlled by gmux. The earliest generation
0277  * MBP5 2008/09 uses a `TI LP8543`_ backlight driver. All newer models
0278  * use a `TI LP8545`_.
0279  *
0280  * .. _TI LP8543: https://www.ti.com/lit/ds/symlink/lp8543.pdf
0281  * .. _TI LP8545: https://www.ti.com/lit/ds/symlink/lp8545.pdf
0282  */
0283 
0284 static int gmux_get_brightness(struct backlight_device *bd)
0285 {
0286     struct apple_gmux_data *gmux_data = bl_get_data(bd);
0287     return gmux_read32(gmux_data, GMUX_PORT_BRIGHTNESS) &
0288            GMUX_BRIGHTNESS_MASK;
0289 }
0290 
0291 static int gmux_update_status(struct backlight_device *bd)
0292 {
0293     struct apple_gmux_data *gmux_data = bl_get_data(bd);
0294     u32 brightness = backlight_get_brightness(bd);
0295 
0296     gmux_write32(gmux_data, GMUX_PORT_BRIGHTNESS, brightness);
0297 
0298     return 0;
0299 }
0300 
0301 static const struct backlight_ops gmux_bl_ops = {
0302     .options = BL_CORE_SUSPENDRESUME,
0303     .get_brightness = gmux_get_brightness,
0304     .update_status = gmux_update_status,
0305 };
0306 
0307 /**
0308  * DOC: Graphics mux
0309  *
0310  * On pre-retinas, the LVDS outputs of both GPUs feed into gmux which muxes
0311  * either of them to the panel. One of the tricks gmux has up its sleeve is
0312  * to lengthen the blanking interval of its output during a switch to
0313  * synchronize it with the GPU switched to. This allows for a flicker-free
0314  * switch that is imperceptible by the user (`US 8,687,007 B2`_).
0315  *
0316  * On retinas, muxing is no longer done by gmux itself, but by a separate
0317  * chip which is controlled by gmux. The chip is triple sourced, it is
0318  * either an `NXP CBTL06142`_, `TI HD3SS212`_ or `Pericom PI3VDP12412`_.
0319  * The panel is driven with eDP instead of LVDS since the pixel clock
0320  * required for retina resolution exceeds LVDS' limits.
0321  *
0322  * Pre-retinas are able to switch the panel's DDC pins separately.
0323  * This is handled by a `TI SN74LV4066A`_ which is controlled by gmux.
0324  * The inactive GPU can thus probe the panel's EDID without switching over
0325  * the entire panel. Retinas lack this functionality as the chips used for
0326  * eDP muxing are incapable of switching the AUX channel separately (see
0327  * the linked data sheets, Pericom would be capable but this is unused).
0328  * However the retina panel has the NO_AUX_HANDSHAKE_LINK_TRAINING bit set
0329  * in its DPCD, allowing the inactive GPU to skip the AUX handshake and
0330  * set up the output with link parameters pre-calibrated by the active GPU.
0331  *
0332  * The external DP port is only fully switchable on the first two unibody
0333  * MacBook Pro generations, MBP5 2008/09 and MBP6 2010. This is done by an
0334  * `NXP CBTL06141`_ which is controlled by gmux. It's the predecessor of the
0335  * eDP mux on retinas, the difference being support for 2.7 versus 5.4 Gbit/s.
0336  *
0337  * The following MacBook Pro generations replaced the external DP port with a
0338  * combined DP/Thunderbolt port and lost the ability to switch it between GPUs,
0339  * connecting it either to the discrete GPU or the Thunderbolt controller.
0340  * Oddly enough, while the full port is no longer switchable, AUX and HPD
0341  * are still switchable by way of an `NXP CBTL03062`_ (on pre-retinas
0342  * MBP8 2011 and MBP9 2012) or two `TI TS3DS10224`_ (on retinas) under the
0343  * control of gmux. Since the integrated GPU is missing the main link,
0344  * external displays appear to it as phantoms which fail to link-train.
0345  *
0346  * gmux receives the HPD signal of all display connectors and sends an
0347  * interrupt on hotplug. On generations which cannot switch external ports,
0348  * the discrete GPU can then be woken to drive the newly connected display.
0349  * The ability to switch AUX on these generations could be used to improve
0350  * reliability of hotplug detection by having the integrated GPU poll the
0351  * ports while the discrete GPU is asleep, but currently we do not make use
0352  * of this feature.
0353  *
0354  * Our switching policy for the external port is that on those generations
0355  * which are able to switch it fully, the port is switched together with the
0356  * panel when IGD / DIS commands are issued to vga_switcheroo. It is thus
0357  * possible to drive e.g. a beamer on battery power with the integrated GPU.
0358  * The user may manually switch to the discrete GPU if more performance is
0359  * needed.
0360  *
0361  * On all newer generations, the external port can only be driven by the
0362  * discrete GPU. If a display is plugged in while the panel is switched to
0363  * the integrated GPU, *both* GPUs will be in use for maximum performance.
0364  * To decrease power consumption, the user may manually switch to the
0365  * discrete GPU, thereby suspending the integrated GPU.
0366  *
0367  * gmux' initial switch state on bootup is user configurable via the EFI
0368  * variable ``gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9`` (5th byte,
0369  * 1 = IGD, 0 = DIS). Based on this setting, the EFI firmware tells gmux to
0370  * switch the panel and the external DP connector and allocates a framebuffer
0371  * for the selected GPU.
0372  *
0373  * .. _US 8,687,007 B2: https://pimg-fpiw.uspto.gov/fdd/07/870/086/0.pdf
0374  * .. _NXP CBTL06141:   https://www.nxp.com/documents/data_sheet/CBTL06141.pdf
0375  * .. _NXP CBTL06142:   https://www.nxp.com/documents/data_sheet/CBTL06141.pdf
0376  * .. _TI HD3SS212:     https://www.ti.com/lit/ds/symlink/hd3ss212.pdf
0377  * .. _Pericom PI3VDP12412: https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf
0378  * .. _TI SN74LV4066A:  https://www.ti.com/lit/ds/symlink/sn74lv4066a.pdf
0379  * .. _NXP CBTL03062:   http://pdf.datasheetarchive.com/indexerfiles/Datasheets-SW16/DSASW00308511.pdf
0380  * .. _TI TS3DS10224:   https://www.ti.com/lit/ds/symlink/ts3ds10224.pdf
0381  */
0382 
0383 static void gmux_read_switch_state(struct apple_gmux_data *gmux_data)
0384 {
0385     if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_DDC) == 1)
0386         gmux_data->switch_state_ddc = VGA_SWITCHEROO_IGD;
0387     else
0388         gmux_data->switch_state_ddc = VGA_SWITCHEROO_DIS;
0389 
0390     if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_DISPLAY) == 2)
0391         gmux_data->switch_state_display = VGA_SWITCHEROO_IGD;
0392     else
0393         gmux_data->switch_state_display = VGA_SWITCHEROO_DIS;
0394 
0395     if (gmux_read8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL) == 2)
0396         gmux_data->switch_state_external = VGA_SWITCHEROO_IGD;
0397     else
0398         gmux_data->switch_state_external = VGA_SWITCHEROO_DIS;
0399 }
0400 
0401 static void gmux_write_switch_state(struct apple_gmux_data *gmux_data)
0402 {
0403     if (gmux_data->switch_state_ddc == VGA_SWITCHEROO_IGD)
0404         gmux_write8(gmux_data, GMUX_PORT_SWITCH_DDC, 1);
0405     else
0406         gmux_write8(gmux_data, GMUX_PORT_SWITCH_DDC, 2);
0407 
0408     if (gmux_data->switch_state_display == VGA_SWITCHEROO_IGD)
0409         gmux_write8(gmux_data, GMUX_PORT_SWITCH_DISPLAY, 2);
0410     else
0411         gmux_write8(gmux_data, GMUX_PORT_SWITCH_DISPLAY, 3);
0412 
0413     if (gmux_data->switch_state_external == VGA_SWITCHEROO_IGD)
0414         gmux_write8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 2);
0415     else
0416         gmux_write8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 3);
0417 }
0418 
0419 static int gmux_switchto(enum vga_switcheroo_client_id id)
0420 {
0421     apple_gmux_data->switch_state_ddc = id;
0422     apple_gmux_data->switch_state_display = id;
0423     if (apple_gmux_data->external_switchable)
0424         apple_gmux_data->switch_state_external = id;
0425 
0426     gmux_write_switch_state(apple_gmux_data);
0427 
0428     return 0;
0429 }
0430 
0431 static int gmux_switch_ddc(enum vga_switcheroo_client_id id)
0432 {
0433     enum vga_switcheroo_client_id old_ddc_owner =
0434         apple_gmux_data->switch_state_ddc;
0435 
0436     if (id == old_ddc_owner)
0437         return id;
0438 
0439     pr_debug("Switching DDC from %d to %d\n", old_ddc_owner, id);
0440     apple_gmux_data->switch_state_ddc = id;
0441 
0442     if (id == VGA_SWITCHEROO_IGD)
0443         gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1);
0444     else
0445         gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2);
0446 
0447     return old_ddc_owner;
0448 }
0449 
0450 /**
0451  * DOC: Power control
0452  *
0453  * gmux is able to cut power to the discrete GPU. It automatically takes care
0454  * of the correct sequence to tear down and bring up the power rails for
0455  * core voltage, VRAM and PCIe.
0456  */
0457 
0458 static int gmux_set_discrete_state(struct apple_gmux_data *gmux_data,
0459                    enum vga_switcheroo_state state)
0460 {
0461     reinit_completion(&gmux_data->powerchange_done);
0462 
0463     if (state == VGA_SWITCHEROO_ON) {
0464         gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 1);
0465         gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 3);
0466         pr_debug("Discrete card powered up\n");
0467     } else {
0468         gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 1);
0469         gmux_write8(gmux_data, GMUX_PORT_DISCRETE_POWER, 0);
0470         pr_debug("Discrete card powered down\n");
0471     }
0472 
0473     gmux_data->power_state = state;
0474 
0475     if (gmux_data->gpe >= 0 &&
0476         !wait_for_completion_interruptible_timeout(&gmux_data->powerchange_done,
0477                                msecs_to_jiffies(200)))
0478         pr_warn("Timeout waiting for gmux switch to complete\n");
0479 
0480     return 0;
0481 }
0482 
0483 static int gmux_set_power_state(enum vga_switcheroo_client_id id,
0484                 enum vga_switcheroo_state state)
0485 {
0486     if (id == VGA_SWITCHEROO_IGD)
0487         return 0;
0488 
0489     return gmux_set_discrete_state(apple_gmux_data, state);
0490 }
0491 
0492 static enum vga_switcheroo_client_id gmux_get_client_id(struct pci_dev *pdev)
0493 {
0494     /*
0495      * Early Macbook Pros with switchable graphics use nvidia
0496      * integrated graphics. Hardcode that the 9400M is integrated.
0497      */
0498     if (pdev->vendor == PCI_VENDOR_ID_INTEL)
0499         return VGA_SWITCHEROO_IGD;
0500     else if (pdev->vendor == PCI_VENDOR_ID_NVIDIA &&
0501          pdev->device == 0x0863)
0502         return VGA_SWITCHEROO_IGD;
0503     else
0504         return VGA_SWITCHEROO_DIS;
0505 }
0506 
0507 static const struct vga_switcheroo_handler gmux_handler_indexed = {
0508     .switchto = gmux_switchto,
0509     .power_state = gmux_set_power_state,
0510     .get_client_id = gmux_get_client_id,
0511 };
0512 
0513 static const struct vga_switcheroo_handler gmux_handler_classic = {
0514     .switchto = gmux_switchto,
0515     .switch_ddc = gmux_switch_ddc,
0516     .power_state = gmux_set_power_state,
0517     .get_client_id = gmux_get_client_id,
0518 };
0519 
0520 /**
0521  * DOC: Interrupt
0522  *
0523  * gmux is also connected to a GPIO pin of the southbridge and thereby is able
0524  * to trigger an ACPI GPE. On the MBP5 2008/09 it's GPIO pin 22 of the Nvidia
0525  * MCP79, on all following generations it's GPIO pin 6 of the Intel PCH.
0526  * The GPE merely signals that an interrupt occurred, the actual type of event
0527  * is identified by reading a gmux register.
0528  */
0529 
0530 static inline void gmux_disable_interrupts(struct apple_gmux_data *gmux_data)
0531 {
0532     gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
0533             GMUX_INTERRUPT_DISABLE);
0534 }
0535 
0536 static inline void gmux_enable_interrupts(struct apple_gmux_data *gmux_data)
0537 {
0538     gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
0539             GMUX_INTERRUPT_ENABLE);
0540 }
0541 
0542 static inline u8 gmux_interrupt_get_status(struct apple_gmux_data *gmux_data)
0543 {
0544     return gmux_read8(gmux_data, GMUX_PORT_INTERRUPT_STATUS);
0545 }
0546 
0547 static void gmux_clear_interrupts(struct apple_gmux_data *gmux_data)
0548 {
0549     u8 status;
0550 
0551     /* to clear interrupts write back current status */
0552     status = gmux_interrupt_get_status(gmux_data);
0553     gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_STATUS, status);
0554 }
0555 
0556 static void gmux_notify_handler(acpi_handle device, u32 value, void *context)
0557 {
0558     u8 status;
0559     struct pnp_dev *pnp = (struct pnp_dev *)context;
0560     struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
0561 
0562     status = gmux_interrupt_get_status(gmux_data);
0563     gmux_disable_interrupts(gmux_data);
0564     pr_debug("Notify handler called: status %d\n", status);
0565 
0566     gmux_clear_interrupts(gmux_data);
0567     gmux_enable_interrupts(gmux_data);
0568 
0569     if (status & GMUX_INTERRUPT_STATUS_POWER)
0570         complete(&gmux_data->powerchange_done);
0571 }
0572 
0573 static int gmux_suspend(struct device *dev)
0574 {
0575     struct pnp_dev *pnp = to_pnp_dev(dev);
0576     struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
0577 
0578     gmux_disable_interrupts(gmux_data);
0579     return 0;
0580 }
0581 
0582 static int gmux_resume(struct device *dev)
0583 {
0584     struct pnp_dev *pnp = to_pnp_dev(dev);
0585     struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
0586 
0587     gmux_enable_interrupts(gmux_data);
0588     gmux_write_switch_state(gmux_data);
0589     if (gmux_data->power_state == VGA_SWITCHEROO_OFF)
0590         gmux_set_discrete_state(gmux_data, gmux_data->power_state);
0591     return 0;
0592 }
0593 
0594 static int is_thunderbolt(struct device *dev, void *data)
0595 {
0596     return to_pci_dev(dev)->is_thunderbolt;
0597 }
0598 
0599 static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
0600 {
0601     struct apple_gmux_data *gmux_data;
0602     struct resource *res;
0603     struct backlight_properties props;
0604     struct backlight_device *bdev;
0605     u8 ver_major, ver_minor, ver_release;
0606     int ret = -ENXIO;
0607     acpi_status status;
0608     unsigned long long gpe;
0609 
0610     if (apple_gmux_data)
0611         return -EBUSY;
0612 
0613     gmux_data = kzalloc(sizeof(*gmux_data), GFP_KERNEL);
0614     if (!gmux_data)
0615         return -ENOMEM;
0616     pnp_set_drvdata(pnp, gmux_data);
0617 
0618     res = pnp_get_resource(pnp, IORESOURCE_IO, 0);
0619     if (!res) {
0620         pr_err("Failed to find gmux I/O resource\n");
0621         goto err_free;
0622     }
0623 
0624     gmux_data->iostart = res->start;
0625     gmux_data->iolen = resource_size(res);
0626 
0627     if (gmux_data->iolen < GMUX_MIN_IO_LEN) {
0628         pr_err("gmux I/O region too small (%lu < %u)\n",
0629                gmux_data->iolen, GMUX_MIN_IO_LEN);
0630         goto err_free;
0631     }
0632 
0633     if (!request_region(gmux_data->iostart, gmux_data->iolen,
0634                 "Apple gmux")) {
0635         pr_err("gmux I/O already in use\n");
0636         goto err_free;
0637     }
0638 
0639     /*
0640      * Invalid version information may indicate either that the gmux
0641      * device isn't present or that it's a new one that uses indexed
0642      * io
0643      */
0644 
0645     ver_major = gmux_read8(gmux_data, GMUX_PORT_VERSION_MAJOR);
0646     ver_minor = gmux_read8(gmux_data, GMUX_PORT_VERSION_MINOR);
0647     ver_release = gmux_read8(gmux_data, GMUX_PORT_VERSION_RELEASE);
0648     if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
0649         if (gmux_is_indexed(gmux_data)) {
0650             u32 version;
0651             mutex_init(&gmux_data->index_lock);
0652             gmux_data->indexed = true;
0653             version = gmux_read32(gmux_data,
0654                 GMUX_PORT_VERSION_MAJOR);
0655             ver_major = (version >> 24) & 0xff;
0656             ver_minor = (version >> 16) & 0xff;
0657             ver_release = (version >> 8) & 0xff;
0658         } else {
0659             pr_info("gmux device not present\n");
0660             ret = -ENODEV;
0661             goto err_release;
0662         }
0663     }
0664     pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor,
0665         ver_release, (gmux_data->indexed ? "indexed" : "classic"));
0666 
0667     memset(&props, 0, sizeof(props));
0668     props.type = BACKLIGHT_PLATFORM;
0669     props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);
0670 
0671     /*
0672      * Currently it's assumed that the maximum brightness is less than
0673      * 2^24 for compatibility with old gmux versions. Cap the max
0674      * brightness at this value, but print a warning if the hardware
0675      * reports something higher so that it can be fixed.
0676      */
0677     if (WARN_ON(props.max_brightness > GMUX_MAX_BRIGHTNESS))
0678         props.max_brightness = GMUX_MAX_BRIGHTNESS;
0679 
0680     bdev = backlight_device_register("gmux_backlight", &pnp->dev,
0681                      gmux_data, &gmux_bl_ops, &props);
0682     if (IS_ERR(bdev)) {
0683         ret = PTR_ERR(bdev);
0684         goto err_release;
0685     }
0686 
0687     gmux_data->bdev = bdev;
0688     bdev->props.brightness = gmux_get_brightness(bdev);
0689     backlight_update_status(bdev);
0690 
0691     /*
0692      * The backlight situation on Macs is complicated. If the gmux is
0693      * present it's the best choice, because it always works for
0694      * backlight control and supports more levels than other options.
0695      * Disable the other backlight choices.
0696      */
0697     acpi_video_set_dmi_backlight_type(acpi_backlight_vendor);
0698     apple_bl_unregister();
0699 
0700     gmux_data->power_state = VGA_SWITCHEROO_ON;
0701 
0702     gmux_data->dhandle = ACPI_HANDLE(&pnp->dev);
0703     if (!gmux_data->dhandle) {
0704         pr_err("Cannot find acpi handle for pnp device %s\n",
0705                dev_name(&pnp->dev));
0706         ret = -ENODEV;
0707         goto err_notify;
0708     }
0709 
0710     status = acpi_evaluate_integer(gmux_data->dhandle, "GMGP", NULL, &gpe);
0711     if (ACPI_SUCCESS(status)) {
0712         gmux_data->gpe = (int)gpe;
0713 
0714         status = acpi_install_notify_handler(gmux_data->dhandle,
0715                              ACPI_DEVICE_NOTIFY,
0716                              &gmux_notify_handler, pnp);
0717         if (ACPI_FAILURE(status)) {
0718             pr_err("Install notify handler failed: %s\n",
0719                    acpi_format_exception(status));
0720             ret = -ENODEV;
0721             goto err_notify;
0722         }
0723 
0724         status = acpi_enable_gpe(NULL, gmux_data->gpe);
0725         if (ACPI_FAILURE(status)) {
0726             pr_err("Cannot enable gpe: %s\n",
0727                    acpi_format_exception(status));
0728             goto err_enable_gpe;
0729         }
0730     } else {
0731         pr_warn("No GPE found for gmux\n");
0732         gmux_data->gpe = -1;
0733     }
0734 
0735     /*
0736      * If Thunderbolt is present, the external DP port is not fully
0737      * switchable. Force its AUX channel to the discrete GPU.
0738      */
0739     gmux_data->external_switchable =
0740         !bus_for_each_dev(&pci_bus_type, NULL, NULL, is_thunderbolt);
0741     if (!gmux_data->external_switchable)
0742         gmux_write8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 3);
0743 
0744     apple_gmux_data = gmux_data;
0745     init_completion(&gmux_data->powerchange_done);
0746     gmux_enable_interrupts(gmux_data);
0747     gmux_read_switch_state(gmux_data);
0748 
0749     /*
0750      * Retina MacBook Pros cannot switch the panel's AUX separately
0751      * and need eDP pre-calibration. They are distinguishable from
0752      * pre-retinas by having an "indexed" gmux.
0753      *
0754      * Pre-retina MacBook Pros can switch the panel's DDC separately.
0755      */
0756     if (gmux_data->indexed)
0757         ret = vga_switcheroo_register_handler(&gmux_handler_indexed,
0758                           VGA_SWITCHEROO_NEEDS_EDP_CONFIG);
0759     else
0760         ret = vga_switcheroo_register_handler(&gmux_handler_classic,
0761                           VGA_SWITCHEROO_CAN_SWITCH_DDC);
0762     if (ret) {
0763         pr_err("Failed to register vga_switcheroo handler\n");
0764         goto err_register_handler;
0765     }
0766 
0767     return 0;
0768 
0769 err_register_handler:
0770     gmux_disable_interrupts(gmux_data);
0771     apple_gmux_data = NULL;
0772     if (gmux_data->gpe >= 0)
0773         acpi_disable_gpe(NULL, gmux_data->gpe);
0774 err_enable_gpe:
0775     if (gmux_data->gpe >= 0)
0776         acpi_remove_notify_handler(gmux_data->dhandle,
0777                        ACPI_DEVICE_NOTIFY,
0778                        &gmux_notify_handler);
0779 err_notify:
0780     backlight_device_unregister(bdev);
0781 err_release:
0782     release_region(gmux_data->iostart, gmux_data->iolen);
0783 err_free:
0784     kfree(gmux_data);
0785     return ret;
0786 }
0787 
0788 static void gmux_remove(struct pnp_dev *pnp)
0789 {
0790     struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
0791 
0792     vga_switcheroo_unregister_handler();
0793     gmux_disable_interrupts(gmux_data);
0794     if (gmux_data->gpe >= 0) {
0795         acpi_disable_gpe(NULL, gmux_data->gpe);
0796         acpi_remove_notify_handler(gmux_data->dhandle,
0797                        ACPI_DEVICE_NOTIFY,
0798                        &gmux_notify_handler);
0799     }
0800 
0801     backlight_device_unregister(gmux_data->bdev);
0802 
0803     release_region(gmux_data->iostart, gmux_data->iolen);
0804     apple_gmux_data = NULL;
0805     kfree(gmux_data);
0806 
0807     acpi_video_register();
0808     apple_bl_register();
0809 }
0810 
0811 static const struct pnp_device_id gmux_device_ids[] = {
0812     {GMUX_ACPI_HID, 0},
0813     {"", 0}
0814 };
0815 
0816 static const struct dev_pm_ops gmux_dev_pm_ops = {
0817     .suspend = gmux_suspend,
0818     .resume = gmux_resume,
0819 };
0820 
0821 static struct pnp_driver gmux_pnp_driver = {
0822     .name       = "apple-gmux",
0823     .probe      = gmux_probe,
0824     .remove     = gmux_remove,
0825     .id_table   = gmux_device_ids,
0826     .driver     = {
0827             .pm = &gmux_dev_pm_ops,
0828     },
0829 };
0830 
0831 module_pnp_driver(gmux_pnp_driver);
0832 MODULE_AUTHOR("Seth Forshee <seth.forshee@canonical.com>");
0833 MODULE_DESCRIPTION("Apple Gmux Driver");
0834 MODULE_LICENSE("GPL");
0835 MODULE_DEVICE_TABLE(pnp, gmux_device_ids);
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