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#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_pci, 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		    !pci_is_display(display_dev))
159			continue;
160
161		if (pci_match_id(denylist, display_dev))
162			continue;
163
164		if (connectivity_check(display_dev, hdac_pci)) {
165			pci_dev_put(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				  i915_component_master_match,
195				  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(bus->dev, -EPROBE_DEFER,
204				     "couldn't bind with audio component\n");
205	}
206	return 0;
207}
208EXPORT_SYMBOL_GPL(snd_hdac_i915_init);