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/*
* hdac_i915.c - routines for sync between HD-A core and i915 display driver
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <sound/core.h>
#include <sound/hdaudio.h>
#include <sound/hda_i915.h>
#include <sound/hda_register.h>
static struct completion bind_complete;
#define CONTROLLER_IN_GPU(pci) (((pci)->device == 0x0a0c) || \
((pci)->device == 0x0c0c) || \
((pci)->device == 0x0d0c) || \
((pci)->device == 0x160c))
/**
* snd_hdac_i915_set_bclk - Reprogram BCLK for HSW/BDW
* @bus: HDA core bus
*
* Intel HSW/BDW display HDA controller is in GPU. Both its power and link BCLK
* depends on GPU. Two Extended Mode registers EM4 (M value) and EM5 (N Value)
* are used to convert CDClk (Core Display Clock) to 24MHz BCLK:
* BCLK = CDCLK * M / N
* The values will be lost when the display power well is disabled and need to
* be restored to avoid abnormal playback speed.
*
* Call this function at initializing and changing power well, as well as
* at ELD notifier for the hotplug.
*/
void snd_hdac_i915_set_bclk(struct hdac_bus *bus)
{
struct drm_audio_component *acomp = bus->audio_component;
struct pci_dev *pci = to_pci_dev(bus->dev);
int cdclk_freq;
unsigned int bclk_m, bclk_n;
if (!acomp || !acomp->ops || !acomp->ops->get_cdclk_freq)
return; /* only for i915 binding */
if (!CONTROLLER_IN_GPU(pci))
return; /* only HSW/BDW */
cdclk_freq = acomp->ops->get_cdclk_freq(acomp->dev);
switch (cdclk_freq) {
case 337500:
bclk_m = 16;
bclk_n = 225;
break;
case 450000:
default: /* default CDCLK 450MHz */
bclk_m = 4;
bclk_n = 75;
break;
case 540000:
bclk_m = 4;
bclk_n = 90;
break;
case 675000:
bclk_m = 8;
bclk_n = 225;
break;
}
snd_hdac_chip_writew(bus, HSW_EM4, bclk_m);
snd_hdac_chip_writew(bus, HSW_EM5, bclk_n);
}
EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk);
static int i915_component_master_match(struct device *dev, void *data)
{
return !strcmp(dev->driver->name, "i915");
}
/* check whether intel graphics is present */
static bool i915_gfx_present(void)
{
static const struct pci_device_id ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ANY_ID),
.class = PCI_BASE_CLASS_DISPLAY << 16,
.class_mask = 0xff << 16 },
{}
};
return pci_dev_present(ids);
}
static int i915_master_bind(struct device *dev,
struct drm_audio_component *acomp)
{
complete_all(&bind_complete);
/* clear audio_ops here as it was needed only for completion call */
acomp->audio_ops = NULL;
return 0;
}
static const struct drm_audio_component_audio_ops i915_init_ops = {
.master_bind = i915_master_bind
};
/**
* snd_hdac_i915_init - Initialize i915 audio component
* @bus: HDA core bus
*
* This function is supposed to be used only by a HD-audio controller
* driver that needs the interaction with i915 graphics.
*
* This function initializes and sets up the audio component to communicate
* with i915 graphics driver.
*
* Returns zero for success or a negative error code.
*/
int snd_hdac_i915_init(struct hdac_bus *bus)
{
struct drm_audio_component *acomp;
int err;
if (!i915_gfx_present())
return -ENODEV;
init_completion(&bind_complete);
err = snd_hdac_acomp_init(bus, &i915_init_ops,
i915_component_master_match,
sizeof(struct i915_audio_component) - sizeof(*acomp));
if (err < 0)
return err;
acomp = bus->audio_component;
if (!acomp)
return -ENODEV;
if (!acomp->ops) {
request_module("i915");
/* 10s timeout */
wait_for_completion_timeout(&bind_complete, 10 * 1000);
}
if (!acomp->ops) {
snd_hdac_acomp_exit(bus);
return -ENODEV;
}
return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_i915_init);
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