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-rw-r--r--sound/hda/hdac_i915.c179
1 files changed, 179 insertions, 0 deletions
diff --git a/sound/hda/hdac_i915.c b/sound/hda/hdac_i915.c
new file mode 100644
index 000000000..161a9711c
--- /dev/null
+++ b/sound/hda/hdac_i915.c
@@ -0,0 +1,179 @@
+// 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>
+
+#define IS_HSW_CONTROLLER(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 (!IS_HSW_CONTROLLER(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;
+
+ /*
+ * 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_b)
+ return false;
+ 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);