1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * hdac_i915.c - routines for sync between HD-A core and i915 display driver
6 #include <linux/init.h>
7 #include <linux/module.h>
9 #include <sound/core.h>
10 #include <sound/hdaudio.h>
11 #include <sound/hda_i915.h>
12 #include <sound/hda_register.h>
14 static struct completion bind_complete;
16 #define IS_HSW_CONTROLLER(pci) (((pci)->device == 0x0a0c) || \
17 ((pci)->device == 0x0c0c) || \
18 ((pci)->device == 0x0d0c) || \
19 ((pci)->device == 0x160c))
22 * snd_hdac_i915_set_bclk - Reprogram BCLK for HSW/BDW
25 * Intel HSW/BDW display HDA controller is in GPU. Both its power and link BCLK
26 * depends on GPU. Two Extended Mode registers EM4 (M value) and EM5 (N Value)
27 * are used to convert CDClk (Core Display Clock) to 24MHz BCLK:
28 * BCLK = CDCLK * M / N
29 * The values will be lost when the display power well is disabled and need to
30 * be restored to avoid abnormal playback speed.
32 * Call this function at initializing and changing power well, as well as
33 * at ELD notifier for the hotplug.
35 void snd_hdac_i915_set_bclk(struct hdac_bus *bus)
37 struct drm_audio_component *acomp = bus->audio_component;
38 struct pci_dev *pci = to_pci_dev(bus->dev);
40 unsigned int bclk_m, bclk_n;
42 if (!acomp || !acomp->ops || !acomp->ops->get_cdclk_freq)
43 return; /* only for i915 binding */
44 if (!IS_HSW_CONTROLLER(pci))
45 return; /* only HSW/BDW */
47 cdclk_freq = acomp->ops->get_cdclk_freq(acomp->dev);
55 default: /* default CDCLK 450MHz */
71 snd_hdac_chip_writew(bus, HSW_EM4, bclk_m);
72 snd_hdac_chip_writew(bus, HSW_EM5, bclk_n);
74 EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk);
76 /* returns true if the devices can be connected for audio */
77 static bool connectivity_check(struct pci_dev *i915, struct pci_dev *hdac)
79 struct pci_bus *bus_a = i915->bus, *bus_b = hdac->bus;
81 /* directly connected on the same bus */
86 * on i915 discrete GPUs with embedded HDA audio, the two
87 * devices are connected via 2nd level PCI bridge
89 bus_a = bus_a->parent;
90 bus_b = bus_b->parent;
93 bus_a = bus_a->parent;
94 bus_b = bus_b->parent;
95 if (bus_a && bus_a == bus_b)
101 static int i915_component_master_match(struct device *dev, int subcomponent,
104 struct pci_dev *hdac_pci, *i915_pci;
105 struct hdac_bus *bus = data;
107 if (!dev_is_pci(dev))
110 hdac_pci = to_pci_dev(bus->dev);
111 i915_pci = to_pci_dev(dev);
113 if (!strcmp(dev->driver->name, "i915") &&
114 subcomponent == I915_COMPONENT_AUDIO &&
115 connectivity_check(i915_pci, hdac_pci))
121 /* check whether intel graphics is present */
122 static bool i915_gfx_present(void)
124 static const struct pci_device_id ids[] = {
125 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ANY_ID),
126 .class = PCI_BASE_CLASS_DISPLAY << 16,
127 .class_mask = 0xff << 16 },
130 return pci_dev_present(ids);
133 static int i915_master_bind(struct device *dev,
134 struct drm_audio_component *acomp)
136 complete_all(&bind_complete);
137 /* clear audio_ops here as it was needed only for completion call */
138 acomp->audio_ops = NULL;
142 static const struct drm_audio_component_audio_ops i915_init_ops = {
143 .master_bind = i915_master_bind
147 * snd_hdac_i915_init - Initialize i915 audio component
150 * This function is supposed to be used only by a HD-audio controller
151 * driver that needs the interaction with i915 graphics.
153 * This function initializes and sets up the audio component to communicate
154 * with i915 graphics driver.
156 * Returns zero for success or a negative error code.
158 int snd_hdac_i915_init(struct hdac_bus *bus)
160 struct drm_audio_component *acomp;
163 if (!i915_gfx_present())
166 init_completion(&bind_complete);
168 err = snd_hdac_acomp_init(bus, &i915_init_ops,
169 i915_component_master_match,
170 sizeof(struct i915_audio_component) - sizeof(*acomp));
173 acomp = bus->audio_component;
177 if (!IS_ENABLED(CONFIG_MODULES) ||
178 !request_module("i915")) {
180 wait_for_completion_timeout(&bind_complete,
181 msecs_to_jiffies(60 * 1000));
185 dev_info(bus->dev, "couldn't bind with audio component\n");
186 snd_hdac_acomp_exit(bus);
191 EXPORT_SYMBOL_GPL(snd_hdac_i915_init);