diff options
Diffstat (limited to 'sound/hda/hdac_i915.c')
| -rw-r--r-- | sound/hda/hdac_i915.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/sound/hda/hdac_i915.c b/sound/hda/hdac_i915.c new file mode 100644 index 0000000000..b428537f28 --- /dev/null +++ b/sound/hda/hdac_i915.c @@ -0,0 +1,180 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * hdac_i915.c - routines for sync between HD-A core and i915 display driver + */ + +#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> + +/** + * 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 (!HDA_CONTROLLER_IS_HSW(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); + +/* returns true if the devices can be connected for audio */ +static bool connectivity_check(struct pci_dev *i915, struct pci_dev *hdac) +{ + struct pci_bus *bus_a = i915->bus, *bus_b = hdac->bus; + + /* directly connected on the same bus */ + if (bus_a == bus_b) + return true; + + bus_a = bus_a->parent; + bus_b = bus_b->parent; + + /* connected via parent bus (may be NULL!) */ + if (bus_a == bus_b) + return true; + + if (!bus_a || !bus_b) + return false; + + /* + * on i915 discrete GPUs with embedded HDA audio, the two + * devices are connected via 2nd level PCI bridge + */ + bus_a = bus_a->parent; + bus_b = bus_b->parent; + if (bus_a && bus_a == bus_b) + return true; + + return false; +} + +static int i915_component_master_match(struct device *dev, int subcomponent, + void *data) +{ + struct pci_dev *hdac_pci, *i915_pci; + struct hdac_bus *bus = data; + + if (!dev_is_pci(dev)) + return 0; + + hdac_pci = to_pci_dev(bus->dev); + i915_pci = to_pci_dev(dev); + + if (!strcmp(dev->driver->name, "i915") && + subcomponent == I915_COMPONENT_AUDIO && + connectivity_check(i915_pci, hdac_pci)) + return 1; + + return 0; +} + +/* check whether Intel graphics is present and reachable */ +static int i915_gfx_present(struct pci_dev *hdac_pci) +{ + struct pci_dev *display_dev = NULL; + + for_each_pci_dev(display_dev) { + if (display_dev->vendor == PCI_VENDOR_ID_INTEL && + (display_dev->class >> 16) == PCI_BASE_CLASS_DISPLAY && + connectivity_check(display_dev, hdac_pci)) { + pci_dev_put(display_dev); + return true; + } + } + + return false; +} + +/** + * 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(to_pci_dev(bus->dev))) + return -ENODEV; + + err = snd_hdac_acomp_init(bus, NULL, + 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) { + if (!IS_ENABLED(CONFIG_MODULES) || + !request_module("i915")) { + /* 60s timeout */ + wait_for_completion_killable_timeout(&acomp->master_bind_complete, + msecs_to_jiffies(60 * 1000)); + } + } + if (!acomp->ops) { + dev_info(bus->dev, "couldn't bind with audio component\n"); + snd_hdac_acomp_exit(bus); + return -ENODEV; + } + return 0; +} +EXPORT_SYMBOL_GPL(snd_hdac_i915_init); |