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#include <video/nomodeset.h>
14
15static int gpu_bind = -1;
16module_param(gpu_bind, int, 0644);
17MODULE_PARM_DESC(gpu_bind, "Whether to bind sound component to GPU "
18 "(1=always, 0=never, -1=on nomodeset(default))");
19
20/**
21 * snd_hdac_i915_set_bclk - Reprogram BCLK for HSW/BDW
22 * @bus: HDA core bus
23 *
24 * Intel HSW/BDW display HDA controller is in GPU. Both its power and link BCLK
25 * depends on GPU. Two Extended Mode registers EM4 (M value) and EM5 (N Value)
26 * are used to convert CDClk (Core Display Clock) to 24MHz BCLK:
27 * BCLK = CDCLK * M / N
28 * The values will be lost when the display power well is disabled and need to
29 * be restored to avoid abnormal playback speed.
30 *
31 * Call this function at initializing and changing power well, as well as
32 * at ELD notifier for the hotplug.
33 */
34void snd_hdac_i915_set_bclk(struct hdac_bus *bus)
35{
36 struct drm_audio_component *acomp = bus->audio_component;
37 struct pci_dev *pci = to_pci_dev(bus->dev);
38 int cdclk_freq;
39 unsigned int bclk_m, bclk_n;
40
41 if (!acomp || !acomp->ops || !acomp->ops->get_cdclk_freq)
42 return; /* only for i915 binding */
43 if (!HDA_CONTROLLER_IS_HSW(pci))
44 return; /* only HSW/BDW */
45
46 cdclk_freq = acomp->ops->get_cdclk_freq(acomp->dev);
47 switch (cdclk_freq) {
48 case 337500:
49 bclk_m = 16;
50 bclk_n = 225;
51 break;
52
53 case 450000:
54 default: /* default CDCLK 450MHz */
55 bclk_m = 4;
56 bclk_n = 75;
57 break;
58
59 case 540000:
60 bclk_m = 4;
61 bclk_n = 90;
62 break;
63
64 case 675000:
65 bclk_m = 8;
66 bclk_n = 225;
67 break;
68 }
69
70 snd_hdac_chip_writew(bus, HSW_EM4, bclk_m);
71 snd_hdac_chip_writew(bus, HSW_EM5, bclk_n);
72}
73EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk);
74
75/* returns true if the devices can be connected for audio */
76static bool connectivity_check(struct pci_dev *i915, struct pci_dev *hdac)
77{
78 struct pci_bus *bus_a = i915->bus, *bus_b = hdac->bus;
79
80 /* directly connected on the same bus */
81 if (bus_a == bus_b)
82 return true;
83
84 bus_a = bus_a->parent;
85 bus_b = bus_b->parent;
86
87 /* connected via parent bus (may be NULL!) */
88 if (bus_a == bus_b)
89 return true;
90
91 if (!bus_a || !bus_b)
92 return false;
93
94 /*
95 * on i915 discrete GPUs with embedded HDA audio, the two
96 * devices are connected via 2nd level PCI bridge
97 */
98 bus_a = bus_a->parent;
99 bus_b = bus_b->parent;
100 if (bus_a && bus_a == bus_b)
101 return true;
102
103 return false;
104}
105
106static int i915_component_master_match(struct device *dev, int subcomponent,
107 void *data)
108{
109 struct pci_dev *hdac_pci, *i915_pci;
110 struct hdac_bus *bus = data;
111
112 if (!dev_is_pci(dev))
113 return 0;
114
115 hdac_pci = to_pci_dev(bus->dev);
116 i915_pci = to_pci_dev(dev);
117
118 if ((!strcmp(dev->driver->name, "i915") ||
119 !strcmp(dev->driver->name, "xe")) &&
120 subcomponent == I915_COMPONENT_AUDIO &&
121 connectivity_check(i915: i915_pci, hdac: hdac_pci))
122 return 1;
123
124 return 0;
125}
126
127/* check whether Intel graphics is present and reachable */
128static int i915_gfx_present(struct pci_dev *hdac_pci)
129{
130 /* List of known platforms with no i915 support. */
131 static const struct pci_device_id denylist[] = {
132 /* CNL */
133 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a40), 0x030000, 0xff0000 },
134 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a41), 0x030000, 0xff0000 },
135 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a42), 0x030000, 0xff0000 },
136 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a44), 0x030000, 0xff0000 },
137 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a49), 0x030000, 0xff0000 },
138 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a4a), 0x030000, 0xff0000 },
139 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a4c), 0x030000, 0xff0000 },
140 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a50), 0x030000, 0xff0000 },
141 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a51), 0x030000, 0xff0000 },
142 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a52), 0x030000, 0xff0000 },
143 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a54), 0x030000, 0xff0000 },
144 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a59), 0x030000, 0xff0000 },
145 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a5a), 0x030000, 0xff0000 },
146 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x5a5c), 0x030000, 0xff0000 },
147 /* LKF */
148 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x9840), 0x030000, 0xff0000 },
149 {}
150 };
151 struct pci_dev *display_dev = NULL;
152
153 if (!gpu_bind || (gpu_bind < 0 && video_firmware_drivers_only()))
154 return false;
155
156 for_each_pci_dev(display_dev) {
157 if (display_dev->vendor != PCI_VENDOR_ID_INTEL ||
158 (display_dev->class >> 16) != PCI_BASE_CLASS_DISPLAY)
159 continue;
160
161 if (pci_match_id(ids: denylist, dev: display_dev))
162 continue;
163
164 if (connectivity_check(i915: display_dev, hdac: hdac_pci)) {
165 pci_dev_put(dev: display_dev);
166 return true;
167 }
168 }
169
170 return false;
171}
172
173/**
174 * snd_hdac_i915_init - Initialize i915 audio component
175 * @bus: HDA core bus
176 *
177 * This function is supposed to be used only by a HD-audio controller
178 * driver that needs the interaction with i915 graphics.
179 *
180 * This function initializes and sets up the audio component to communicate
181 * with i915 graphics driver.
182 *
183 * Returns zero for success or a negative error code.
184 */
185int snd_hdac_i915_init(struct hdac_bus *bus)
186{
187 struct drm_audio_component *acomp;
188 int err;
189
190 if (!i915_gfx_present(to_pci_dev(bus->dev)))
191 return -ENODEV;
192
193 err = snd_hdac_acomp_init(bus, NULL,
194 match_master: i915_component_master_match,
195 extra_size: sizeof(struct i915_audio_component) - sizeof(*acomp));
196 if (err < 0)
197 return err;
198 acomp = bus->audio_component;
199 if (!acomp)
200 return -ENODEV;
201 if (!acomp->ops) {
202 snd_hdac_acomp_exit(bus);
203 return dev_err_probe(dev: bus->dev, err: -EPROBE_DEFER,
204 fmt: "couldn't bind with audio component\n");
205 }
206 return 0;
207}
208EXPORT_SYMBOL_GPL(snd_hdac_i915_init);
209

source code of linux/sound/hda/hdac_i915.c