sound/hda/hdac_i915.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  hdac_i915.c - routines for sync between HD-A core and i915 display driver
   4  */
   5
   6 #include <linux/init.h>
   7 #include <linux/module.h>
   8 #include <linux/pci.h>
   9 #include <sound/core.h>
  10 #include <sound/hdaudio.h>
  11 #include <sound/hda_i915.h>
  12 #include <sound/hda_register.h>
  13
  14 #define IS_HSW_CONTROLLER(pci) (((pci)->device == 0x0a0c) || \
  15                                 ((pci)->device == 0x0c0c) || \
  16                                 ((pci)->device == 0x0d0c) || \
  17                                 ((pci)->device == 0x160c))
  18
  19 /**
  20  * snd_hdac_i915_set_bclk - Reprogram BCLK for HSW/BDW
  21  * @bus: HDA core bus
  22  *
  23  * Intel HSW/BDW display HDA controller is in GPU. Both its power and link BCLK
  24  * depends on GPU. Two Extended Mode registers EM4 (M value) and EM5 (N Value)
  25  * are used to convert CDClk (Core Display Clock) to 24MHz BCLK:
  26  * BCLK = CDCLK * M / N
  27  * The values will be lost when the display power well is disabled and need to
  28  * be restored to avoid abnormal playback speed.
  29  *
  30  * Call this function at initializing and changing power well, as well as
  31  * at ELD notifier for the hotplug.
  32  */
  33 void snd_hdac_i915_set_bclk(struct hdac_bus *bus)
  34 {
  35         struct drm_audio_component *acomp = bus->audio_component;
  36         struct pci_dev *pci = to_pci_dev(bus->dev);
  37         int cdclk_freq;
  38         unsigned int bclk_m, bclk_n;
  39
  40         if (!acomp || !acomp->ops || !acomp->ops->get_cdclk_freq)
  41                 return; /* only for i915 binding */
  42         if (!IS_HSW_CONTROLLER(pci))
  43                 return; /* only HSW/BDW */
  44
  45         cdclk_freq = acomp->ops->get_cdclk_freq(acomp->dev);
  46         switch (cdclk_freq) {
  47         case 337500:
  48                 bclk_m = 16;
  49                 bclk_n = 225;
  50                 break;
  51
  52         case 450000:
  53         default: /* default CDCLK 450MHz */
  54                 bclk_m = 4;
  55                 bclk_n = 75;
  56                 break;
  57
  58         case 540000:
  59                 bclk_m = 4;
  60                 bclk_n = 90;
  61                 break;
  62
  63         case 675000:
  64                 bclk_m = 8;
  65                 bclk_n = 225;
  66                 break;
  67         }
  68
  69         snd_hdac_chip_writew(bus, HSW_EM4, bclk_m);
  70         snd_hdac_chip_writew(bus, HSW_EM5, bclk_n);
  71 }
  72 EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk);
  73
  74 /* returns true if the devices can be connected for audio */
  75 static bool connectivity_check(struct pci_dev *i915, struct pci_dev *hdac)
  76 {
  77         struct pci_bus *bus_a = i915->bus, *bus_b = hdac->bus;
  78
  79         /* directly connected on the same bus */
  80         if (bus_a == bus_b)
  81                 return true;
  82
  83         /*
  84          * on i915 discrete GPUs with embedded HDA audio, the two
  85          * devices are connected via 2nd level PCI bridge
  86          */
  87         bus_a = bus_a->parent;
  88         bus_b = bus_b->parent;
  89         if (!bus_a || !bus_b)
  90                 return false;
  91         bus_a = bus_a->parent;
  92         bus_b = bus_b->parent;
  93         if (bus_a && bus_a == bus_b)
  94                 return true;
  95
  96         return false;
  97 }
  98
  99 static int i915_component_master_match(struct device *dev, int subcomponent,
 100                                        void *data)
 101 {
 102         struct pci_dev *hdac_pci, *i915_pci;
 103         struct hdac_bus *bus = data;
 104
 105         if (!dev_is_pci(dev))
 106                 return 0;
 107
 108         hdac_pci = to_pci_dev(bus->dev);
 109         i915_pci = to_pci_dev(dev);
 110
 111         if (!strcmp(dev->driver->name, "i915") &&
 112             subcomponent == I915_COMPONENT_AUDIO &&
 113             connectivity_check(i915_pci, hdac_pci))
 114                 return 1;
 115
 116         return 0;
 117 }
 118
 119 /* check whether intel graphics is present */
 120 static bool i915_gfx_present(void)
 121 {
 122         static const struct pci_device_id ids[] = {
 123                 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ANY_ID),
 124                   .class = PCI_BASE_CLASS_DISPLAY << 16,
 125                   .class_mask = 0xff << 16 },
 126                 {}
 127         };
 128         return pci_dev_present(ids);
 129 }
 130
 131 /**
 132  * snd_hdac_i915_init - Initialize i915 audio component
 133  * @bus: HDA core bus
 134  *
 135  * This function is supposed to be used only by a HD-audio controller
 136  * driver that needs the interaction with i915 graphics.
 137  *
 138  * This function initializes and sets up the audio component to communicate
 139  * with i915 graphics driver.
 140  *
 141  * Returns zero for success or a negative error code.
 142  */
 143 int snd_hdac_i915_init(struct hdac_bus *bus)
 144 {
 145         struct drm_audio_component *acomp;
 146         int err;
 147
 148         if (!i915_gfx_present())
 149                 return -ENODEV;
 150
 151         err = snd_hdac_acomp_init(bus, NULL,
 152                                   i915_component_master_match,
 153                                   sizeof(struct i915_audio_component) - sizeof(*acomp));
 154         if (err < 0)
 155                 return err;
 156         acomp = bus->audio_component;
 157         if (!acomp)
 158                 return -ENODEV;
 159         if (!acomp->ops) {
 160                 if (!IS_ENABLED(CONFIG_MODULES) ||
 161                     !request_module("i915")) {
 162                         /* 60s timeout */
 163                         wait_for_completion_timeout(&acomp->master_bind_complete,
 164                                                     msecs_to_jiffies(60 * 1000));
 165                 }
 166         }
 167         if (!acomp->ops) {
 168                 dev_info(bus->dev, "couldn't bind with audio component\n");
 169                 snd_hdac_acomp_exit(bus);
 170                 return -ENODEV;
 171         }
 172         return 0;
 173 }
 174 EXPORT_SYMBOL_GPL(snd_hdac_i915_init);