xref: /kernel/linux/linux-5.10/sound/hda/hdac_i915.c (revision 8c2ecf20) 
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 */
33void 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}
72EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk);
73
74/* returns true if the devices can be connected for audio */
75static 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
99static 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 */
120static 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 */
143int 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}
174EXPORT_SYMBOL_GPL(snd_hdac_i915_init);
175