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 static struct completion bind_complete;
15
16 #define CONTROLLER_IN_GPU(pci) (((pci)->device == 0x0a0c) || \
17 ((pci)->device == 0x0c0c) || \
18 ((pci)->device == 0x0d0c) || \
19 ((pci)->device == 0x160c))
20
21 /**
22 * snd_hdac_i915_set_bclk - Reprogram BCLK for HSW/BDW
23 * @bus: HDA core bus
24 *
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.
31 *
32 * Call this function at initializing and changing power well, as well as
33 * at ELD notifier for the hotplug.
34 */
snd_hdac_i915_set_bclk(struct hdac_bus * bus)35 void snd_hdac_i915_set_bclk(struct hdac_bus *bus)
36 {
37 struct drm_audio_component *acomp = bus->audio_component;
38 struct pci_dev *pci = to_pci_dev(bus->dev);
39 int cdclk_freq;
40 unsigned int bclk_m, bclk_n;
41
42 if (!acomp || !acomp->ops || !acomp->ops->get_cdclk_freq)
43 return; /* only for i915 binding */
44 if (!CONTROLLER_IN_GPU(pci))
45 return; /* only HSW/BDW */
46
47 cdclk_freq = acomp->ops->get_cdclk_freq(acomp->dev);
48 switch (cdclk_freq) {
49 case 337500:
50 bclk_m = 16;
51 bclk_n = 225;
52 break;
53
54 case 450000:
55 default: /* default CDCLK 450MHz */
56 bclk_m = 4;
57 bclk_n = 75;
58 break;
59
60 case 540000:
61 bclk_m = 4;
62 bclk_n = 90;
63 break;
64
65 case 675000:
66 bclk_m = 8;
67 bclk_n = 225;
68 break;
69 }
70
71 snd_hdac_chip_writew(bus, HSW_EM4, bclk_m);
72 snd_hdac_chip_writew(bus, HSW_EM5, bclk_n);
73 }
74 EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk);
75
i915_component_master_match(struct device * dev,int subcomponent,void * data)76 static int i915_component_master_match(struct device *dev, int subcomponent,
77 void *data)
78 {
79 return !strcmp(dev->driver->name, "i915") &&
80 subcomponent == I915_COMPONENT_AUDIO;
81 }
82
83 /* check whether intel graphics is present */
i915_gfx_present(void)84 static bool i915_gfx_present(void)
85 {
86 static const struct pci_device_id ids[] = {
87 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ANY_ID),
88 .class = PCI_BASE_CLASS_DISPLAY << 16,
89 .class_mask = 0xff << 16 },
90 {}
91 };
92 return pci_dev_present(ids);
93 }
94
i915_master_bind(struct device * dev,struct drm_audio_component * acomp)95 static int i915_master_bind(struct device *dev,
96 struct drm_audio_component *acomp)
97 {
98 complete_all(&bind_complete);
99 /* clear audio_ops here as it was needed only for completion call */
100 acomp->audio_ops = NULL;
101 return 0;
102 }
103
104 static const struct drm_audio_component_audio_ops i915_init_ops = {
105 .master_bind = i915_master_bind
106 };
107
108 /**
109 * snd_hdac_i915_init - Initialize i915 audio component
110 * @bus: HDA core bus
111 *
112 * This function is supposed to be used only by a HD-audio controller
113 * driver that needs the interaction with i915 graphics.
114 *
115 * This function initializes and sets up the audio component to communicate
116 * with i915 graphics driver.
117 *
118 * Returns zero for success or a negative error code.
119 */
snd_hdac_i915_init(struct hdac_bus * bus)120 int snd_hdac_i915_init(struct hdac_bus *bus)
121 {
122 struct drm_audio_component *acomp;
123 int err;
124
125 if (!i915_gfx_present())
126 return -ENODEV;
127
128 init_completion(&bind_complete);
129
130 err = snd_hdac_acomp_init(bus, &i915_init_ops,
131 i915_component_master_match,
132 sizeof(struct i915_audio_component) - sizeof(*acomp));
133 if (err < 0)
134 return err;
135 acomp = bus->audio_component;
136 if (!acomp)
137 return -ENODEV;
138 if (!acomp->ops) {
139 if (!IS_ENABLED(CONFIG_MODULES) ||
140 !request_module("i915")) {
141 /* 60s timeout */
142 wait_for_completion_timeout(&bind_complete,
143 msecs_to_jiffies(60 * 1000));
144 }
145 }
146 if (!acomp->ops) {
147 dev_info(bus->dev, "couldn't bind with audio component\n");
148 snd_hdac_acomp_exit(bus);
149 return -ENODEV;
150 }
151 return 0;
152 }
153 EXPORT_SYMBOL_GPL(snd_hdac_i915_init);
154