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179 lines
4.4 KiB
179 lines
4.4 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* hdac_i915.c - routines for sync between HD-A core and i915 display driver |
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*/ |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <linux/pci.h> |
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#include <sound/core.h> |
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#include <sound/hdaudio.h> |
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#include <sound/hda_i915.h> |
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#include <sound/hda_register.h> |
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#define IS_HSW_CONTROLLER(pci) (((pci)->device == 0x0a0c) || \ |
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((pci)->device == 0x0c0c) || \ |
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((pci)->device == 0x0d0c) || \ |
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((pci)->device == 0x160c)) |
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/** |
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* snd_hdac_i915_set_bclk - Reprogram BCLK for HSW/BDW |
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* @bus: HDA core bus |
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* |
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* Intel HSW/BDW display HDA controller is in GPU. Both its power and link BCLK |
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* depends on GPU. Two Extended Mode registers EM4 (M value) and EM5 (N Value) |
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* are used to convert CDClk (Core Display Clock) to 24MHz BCLK: |
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* BCLK = CDCLK * M / N |
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* The values will be lost when the display power well is disabled and need to |
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* be restored to avoid abnormal playback speed. |
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* |
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* Call this function at initializing and changing power well, as well as |
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* at ELD notifier for the hotplug. |
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*/ |
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void snd_hdac_i915_set_bclk(struct hdac_bus *bus) |
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{ |
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struct drm_audio_component *acomp = bus->audio_component; |
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struct pci_dev *pci = to_pci_dev(bus->dev); |
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int cdclk_freq; |
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unsigned int bclk_m, bclk_n; |
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if (!acomp || !acomp->ops || !acomp->ops->get_cdclk_freq) |
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return; /* only for i915 binding */ |
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if (!IS_HSW_CONTROLLER(pci)) |
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return; /* only HSW/BDW */ |
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cdclk_freq = acomp->ops->get_cdclk_freq(acomp->dev); |
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switch (cdclk_freq) { |
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case 337500: |
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bclk_m = 16; |
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bclk_n = 225; |
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break; |
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case 450000: |
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default: /* default CDCLK 450MHz */ |
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bclk_m = 4; |
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bclk_n = 75; |
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break; |
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case 540000: |
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bclk_m = 4; |
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bclk_n = 90; |
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break; |
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case 675000: |
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bclk_m = 8; |
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bclk_n = 225; |
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break; |
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} |
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snd_hdac_chip_writew(bus, HSW_EM4, bclk_m); |
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snd_hdac_chip_writew(bus, HSW_EM5, bclk_n); |
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} |
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EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk); |
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/* returns true if the devices can be connected for audio */ |
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static bool connectivity_check(struct pci_dev *i915, struct pci_dev *hdac) |
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{ |
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struct pci_bus *bus_a = i915->bus, *bus_b = hdac->bus; |
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/* directly connected on the same bus */ |
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if (bus_a == bus_b) |
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return true; |
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/* |
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* on i915 discrete GPUs with embedded HDA audio, the two |
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* devices are connected via 2nd level PCI bridge |
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*/ |
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bus_a = bus_a->parent; |
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bus_b = bus_b->parent; |
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if (!bus_a || !bus_b) |
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return false; |
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bus_a = bus_a->parent; |
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bus_b = bus_b->parent; |
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if (bus_a && bus_a == bus_b) |
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return true; |
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return false; |
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} |
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static int i915_component_master_match(struct device *dev, int subcomponent, |
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void *data) |
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{ |
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struct pci_dev *hdac_pci, *i915_pci; |
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struct hdac_bus *bus = data; |
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if (!dev_is_pci(dev)) |
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return 0; |
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hdac_pci = to_pci_dev(bus->dev); |
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i915_pci = to_pci_dev(dev); |
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if (!strcmp(dev->driver->name, "i915") && |
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subcomponent == I915_COMPONENT_AUDIO && |
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connectivity_check(i915_pci, hdac_pci)) |
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return 1; |
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return 0; |
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} |
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/* check whether Intel graphics is present and reachable */ |
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static int i915_gfx_present(struct pci_dev *hdac_pci) |
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{ |
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struct pci_dev *display_dev = NULL; |
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for_each_pci_dev(display_dev) { |
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if (display_dev->vendor == PCI_VENDOR_ID_INTEL && |
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(display_dev->class >> 16) == PCI_BASE_CLASS_DISPLAY && |
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connectivity_check(display_dev, hdac_pci)) { |
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pci_dev_put(display_dev); |
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return true; |
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} |
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} |
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return false; |
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} |
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/** |
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* snd_hdac_i915_init - Initialize i915 audio component |
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* @bus: HDA core bus |
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* |
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* This function is supposed to be used only by a HD-audio controller |
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* driver that needs the interaction with i915 graphics. |
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* |
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* This function initializes and sets up the audio component to communicate |
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* with i915 graphics driver. |
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* |
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* Returns zero for success or a negative error code. |
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*/ |
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int snd_hdac_i915_init(struct hdac_bus *bus) |
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{ |
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struct drm_audio_component *acomp; |
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int err; |
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if (!i915_gfx_present(to_pci_dev(bus->dev))) |
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return -ENODEV; |
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err = snd_hdac_acomp_init(bus, NULL, |
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i915_component_master_match, |
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sizeof(struct i915_audio_component) - sizeof(*acomp)); |
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if (err < 0) |
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return err; |
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acomp = bus->audio_component; |
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if (!acomp) |
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return -ENODEV; |
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if (!acomp->ops) { |
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if (!IS_ENABLED(CONFIG_MODULES) || |
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!request_module("i915")) { |
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/* 60s timeout */ |
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wait_for_completion_killable_timeout(&acomp->master_bind_complete, |
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msecs_to_jiffies(60 * 1000)); |
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} |
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} |
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if (!acomp->ops) { |
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dev_info(bus->dev, "couldn't bind with audio component\n"); |
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snd_hdac_acomp_exit(bus); |
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return -ENODEV; |
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} |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(snd_hdac_i915_init);
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