[alsa-devel] [PATCH] ALSA: hda - disable dynamic clock gating on Broxton before reset

[libin.yang at linux.intel.com]

From: Libin Yang <libin.yang at linux.intel.com>

On Broxton, to make sure the reset controller works properly,
MISCBDCGE bit (bit 6) in CGCTL (0x48) of PCI configuration space
need be cleared before reset and set back to 1 after reset.
Otherwise, it may prevent the CORB/RIRB logic from being reset.

Signed-off-by: Libin Yang <libin.yang at linux.intel.com>
---
 sound/pci/hda/hda_intel.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index aeaa9a5..12c5442 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -90,6 +90,8 @@ enum {
 #define NVIDIA_HDA_ENABLE_COHBIT      0x01
 
 /* Defines for Intel SCH HDA snoop control */
+#define INTEL_HDA_CGCTL	 0x48
+#define INTEL_HDA_CGCTL_MISCBDCGE        (0x1 << 6)
 #define INTEL_SCH_HDA_DEVC      0x78
 #define INTEL_SCH_HDA_DEVC_NOSNOOP       (0x1<<11)
 
@@ -536,10 +538,21 @@ static void hda_intel_init_chip(struct azx *chip, bool full_reset)
 {
 	struct hdac_bus *bus = azx_bus(chip);
 	struct pci_dev *pci = chip->pci;
+	u32 val;
 
 	if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)
 		snd_hdac_set_codec_wakeup(bus, true);
+	if (IS_BROXTON(pci)) {
+		pci_read_config_dword(pci, INTEL_HDA_CGCTL, &val);
+		val = val & (~(INTEL_HDA_CGCTL_MISCBDCGE));
+		pci_write_config_dword(pci, INTEL_HDA_CGCTL, val);
+	}
 	azx_init_chip(chip, full_reset);
+	if (IS_BROXTON(pci)) {
+		pci_read_config_dword(pci, INTEL_HDA_CGCTL, &val);
+		val = val | INTEL_HDA_CGCTL_MISCBDCGE;
+		pci_write_config_dword(pci, INTEL_HDA_CGCTL, val);
+	}
 	if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)
 		snd_hdac_set_codec_wakeup(bus, false);
 
-- 
1.9.1