include/linux/apple-gmux.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * apple-gmux.h - microcontroller built into dual GPU MacBook Pro & Mac Pro
   4  * Copyright (C) 2015 Lukas Wunner <lukas@wunner.de>
   5  */
   6
   7 #ifndef LINUX_APPLE_GMUX_H
   8 #define LINUX_APPLE_GMUX_H
   9
  10 #include <linux/acpi.h>
  11 #include <linux/io.h>
  12 #include <linux/pnp.h>
  13
  14 #define GMUX_ACPI_HID "APP000B"
  15
  16 /*
  17  * gmux port offsets. Many of these are not yet used, but may be in the
  18  * future, and it's useful to have them documented here anyhow.
  19  */
  20 #define GMUX_PORT_VERSION_MAJOR         0x04
  21 #define GMUX_PORT_VERSION_MINOR         0x05
  22 #define GMUX_PORT_VERSION_RELEASE       0x06
  23 #define GMUX_PORT_SWITCH_DISPLAY        0x10
  24 #define GMUX_PORT_SWITCH_GET_DISPLAY    0x11
  25 #define GMUX_PORT_INTERRUPT_ENABLE      0x14
  26 #define GMUX_PORT_INTERRUPT_STATUS      0x16
  27 #define GMUX_PORT_SWITCH_DDC            0x28
  28 #define GMUX_PORT_SWITCH_EXTERNAL       0x40
  29 #define GMUX_PORT_SWITCH_GET_EXTERNAL   0x41
  30 #define GMUX_PORT_DISCRETE_POWER        0x50
  31 #define GMUX_PORT_MAX_BRIGHTNESS        0x70
  32 #define GMUX_PORT_BRIGHTNESS            0x74
  33 #define GMUX_PORT_VALUE                 0xc2
  34 #define GMUX_PORT_READ                  0xd0
  35 #define GMUX_PORT_WRITE                 0xd4
  36
  37 #define GMUX_MMIO_PORT_SELECT           0x0e
  38 #define GMUX_MMIO_COMMAND_SEND          0x0f
  39
  40 #define GMUX_MMIO_READ                  0x00
  41 #define GMUX_MMIO_WRITE                 0x40
  42
  43 #define GMUX_MIN_IO_LEN                 (GMUX_PORT_BRIGHTNESS + 4)
  44
  45 enum apple_gmux_type {
  46         APPLE_GMUX_TYPE_PIO,
  47         APPLE_GMUX_TYPE_INDEXED,
  48         APPLE_GMUX_TYPE_MMIO,
  49 };
  50
  51 #if IS_ENABLED(CONFIG_APPLE_GMUX)
  52 static inline bool apple_gmux_is_indexed(unsigned long iostart)
  53 {
  54         u16 val;
  55
  56         outb(0xaa, iostart + 0xcc);
  57         outb(0x55, iostart + 0xcd);
  58         outb(0x00, iostart + 0xce);
  59
  60         val = inb(iostart + 0xcc) | (inb(iostart + 0xcd) << 8);
  61         if (val == 0x55aa)
  62                 return true;
  63
  64         return false;
  65 }
  66
  67 static inline bool apple_gmux_is_mmio(unsigned long iostart)
  68 {
  69         u8 __iomem *iomem_base = ioremap(iostart, 16);
  70         u8 val;
  71
  72         if (!iomem_base)
  73                 return false;
  74
  75         /*
  76          * If this is 0xff, then gmux must not be present, as the gmux would
  77          * reset it to 0x00, or it would be one of 0x1, 0x4, 0x41, 0x44 if a
  78          * command is currently being processed.
  79          */
  80         val = ioread8(iomem_base + GMUX_MMIO_COMMAND_SEND);
  81         iounmap(iomem_base);
  82         return (val != 0xff);
  83 }
  84
  85 /**
  86  * apple_gmux_detect() - detect if gmux is built into the machine
  87  *
  88  * @pnp_dev:     Device to probe or NULL to use the first matching device
  89  * @type_ret: Returns (by reference) the apple_gmux_type of the device
  90  *
  91  * Detect if a supported gmux device is present by actually probing it.
  92  * This avoids the false positives returned on some models by
  93  * apple_gmux_present().
  94  *
  95  * Return: %true if a supported gmux ACPI device is detected and the kernel
  96  * was configured with CONFIG_APPLE_GMUX, %false otherwise.
  97  */
  98 static inline bool apple_gmux_detect(struct pnp_dev *pnp_dev, enum apple_gmux_type *type_ret)
  99 {
 100         u8 ver_major, ver_minor, ver_release;
 101         struct device *dev = NULL;
 102         struct acpi_device *adev;
 103         struct resource *res;
 104         enum apple_gmux_type type = APPLE_GMUX_TYPE_PIO;
 105         bool ret = false;
 106
 107         if (!pnp_dev) {
 108                 adev = acpi_dev_get_first_match_dev(GMUX_ACPI_HID, NULL, -1);
 109                 if (!adev)
 110                         return false;
 111
 112                 dev = get_device(acpi_get_first_physical_node(adev));
 113                 acpi_dev_put(adev);
 114                 if (!dev)
 115                         return false;
 116
 117                 pnp_dev = to_pnp_dev(dev);
 118         }
 119
 120         res = pnp_get_resource(pnp_dev, IORESOURCE_IO, 0);
 121         if (res && resource_size(res) >= GMUX_MIN_IO_LEN) {
 122                 /*
 123                  * Invalid version information may indicate either that the gmux
 124                  * device isn't present or that it's a new one that uses indexed io.
 125                  */
 126                 ver_major = inb(res->start + GMUX_PORT_VERSION_MAJOR);
 127                 ver_minor = inb(res->start + GMUX_PORT_VERSION_MINOR);
 128                 ver_release = inb(res->start + GMUX_PORT_VERSION_RELEASE);
 129                 if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
 130                         if (apple_gmux_is_indexed(res->start))
 131                                 type = APPLE_GMUX_TYPE_INDEXED;
 132                         else
 133                                 goto out;
 134                 }
 135         } else {
 136                 res = pnp_get_resource(pnp_dev, IORESOURCE_MEM, 0);
 137                 if (res && apple_gmux_is_mmio(res->start))
 138                         type = APPLE_GMUX_TYPE_MMIO;
 139                 else
 140                         goto out;
 141         }
 142
 143         if (type_ret)
 144                 *type_ret = type;
 145
 146         ret = true;
 147 out:
 148         put_device(dev);
 149         return ret;
 150 }
 151
 152 /**
 153  * apple_gmux_present() - check if gmux ACPI device is present
 154  *
 155  * Drivers may use this to activate quirks specific to dual GPU MacBook Pros
 156  * and Mac Pros, e.g. for deferred probing, runtime pm and backlight.
 157  *
 158  * Return: %true if gmux ACPI device is present and the kernel was configured
 159  * with CONFIG_APPLE_GMUX, %false otherwise.
 160  */
 161 static inline bool apple_gmux_present(void)
 162 {
 163         return acpi_dev_found(GMUX_ACPI_HID);
 164 }
 165
 166 #else  /* !CONFIG_APPLE_GMUX */
 167
 168 static inline bool apple_gmux_present(void)
 169 {
 170         return false;
 171 }
 172
 173 static inline bool apple_gmux_detect(struct pnp_dev *pnp_dev, bool *indexed_ret)
 174 {
 175         return false;
 176 }
 177
 178 #endif /* !CONFIG_APPLE_GMUX */
 179
 180 #endif /* LINUX_APPLE_GMUX_H */