ALSA: hda - Add snoop option

Added a new option "snoop" for the traffic control of the HD-audio
controller chip.  When set to 0, the non-snooping mode is used with
the traffic control bit is set in each stream control register.
This may allow better operations in the low power mode, but the actual
implementation is depending pretty much on the chipset.

As already implemented, more or less each chipset has own snoop-control
register bit.  Now this setup refers to the snoop option, too.

Also, a new VIA chipset may require the non-snooping mode when set so
in BIOS.  In such a case, the option value is overridden.

As default, it's still set to snoop=1 for keeping the same behavior as
before.  In near future, it'll be set to 0 as default after checking
it works in every system well.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Documentation/sound/alsa/ALSA-Configuration.txt

@@ -891,6 +891,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
 		      access but isn't required by the HDA spec and prevents
 		      users from specifying exact period/buffer sizes.
 		      (default = on)
+    snoop	- Enable/disable snooping (default = on)
 
     This module supports multiple cards and autoprobe.
     

sound/pci/hda/hda_intel.c

@@ -34,7 +34,6 @@
  * 
  */
 
-#include <asm/io.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -46,6 +45,12 @@
 #include <linux/pci.h>
 #include <linux/mutex.h>
 #include <linux/reboot.h>
+#include <linux/io.h>
+#ifdef CONFIG_X86
+/* for snoop control */
+#include <asm/pgtable.h>
+#include <asm/cacheflush.h>
+#endif
 #include <sound/core.h>
 #include <sound/initval.h>
 #include "hda_codec.h"
@@ -121,6 +126,17 @@ module_param(align_buffer_size, bool, 0644);
 MODULE_PARM_DESC(align_buffer_size,
 		"Force buffer and period sizes to be multiple of 128 bytes.");
 
+#ifdef CONFIG_X86
+static bool hda_snoop = true;
+module_param_named(snoop, hda_snoop, bool, 0444);
+MODULE_PARM_DESC(snoop, "Enable/disable snooping");
+#define azx_snoop(chip)		(chip)->snoop
+#else
+#define hda_snoop		true
+#define azx_snoop(chip)		true
+#endif
+
+
 MODULE_LICENSE("GPL");
 MODULE_SUPPORTED_DEVICE("{{Intel, ICH6},"
 			 "{Intel, ICH6M},"
@@ -376,6 +392,7 @@ struct azx_dev {
 	 *  when link position is not greater than FIFO size
 	 */
 	unsigned int insufficient :1;
+	unsigned int wc_marked:1;
 };
 
 /* CORB/RIRB */
@@ -443,6 +460,7 @@ struct azx {
 	unsigned int msi :1;
 	unsigned int irq_pending_warned :1;
 	unsigned int probing :1; /* codec probing phase */
+	unsigned int snoop:1;
 
 	/* for debugging */
 	unsigned int last_cmd[AZX_MAX_CODECS];
@@ -548,6 +566,45 @@ static char *driver_short_names[] __devinitdata = {
 /* for pcm support */
 #define get_azx_dev(substream) (substream->runtime->private_data)
 
+#ifdef CONFIG_X86
+static void __mark_pages_wc(struct azx *chip, void *addr, size_t size, bool on)
+{
+	if (azx_snoop(chip))
+		return;
+	if (addr && size) {
+		int pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+		if (on)
+			set_memory_wc((unsigned long)addr, pages);
+		else
+			set_memory_wb((unsigned long)addr, pages);
+	}
+}
+
+static inline void mark_pages_wc(struct azx *chip, struct snd_dma_buffer *buf,
+				 bool on)
+{
+	__mark_pages_wc(chip, buf->area, buf->bytes, on);
+}
+static inline void mark_runtime_wc(struct azx *chip, struct azx_dev *azx_dev,
+				   struct snd_pcm_runtime *runtime, bool on)
+{
+	if (azx_dev->wc_marked != on) {
+		__mark_pages_wc(chip, runtime->dma_area, runtime->dma_bytes, on);
+		azx_dev->wc_marked = on;
+	}
+}
+#else
+/* NOP for other archs */
+static inline void mark_pages_wc(struct azx *chip, struct snd_dma_buffer *buf,
+				 bool on)
+{
+}
+static inline void mark_runtime_wc(struct azx *chip, struct azx_dev *azx_dev,
+				   struct snd_pcm_runtime *runtime, bool on)
+{
+}
+#endif
+
 static int azx_acquire_irq(struct azx *chip, int do_disconnect);
 static int azx_send_cmd(struct hda_bus *bus, unsigned int val);
 /*
@@ -569,6 +626,7 @@ static int azx_alloc_cmd_io(struct azx *chip)
 		snd_printk(KERN_ERR SFX "cannot allocate CORB/RIRB\n");
 		return err;
 	}
+	mark_pages_wc(chip, &chip->rb, true);
 	return 0;
 }
 
@@ -1085,7 +1143,15 @@ static void update_pci_byte(struct pci_dev *pci, unsigned int reg,
 
 static void azx_init_pci(struct azx *chip)
 {
-	unsigned short snoop;
+	/* force to non-snoop mode for a new VIA controller when BIOS is set */
+	if (chip->snoop && chip->driver_type == AZX_DRIVER_VIA) {
+		u8 snoop;
+		pci_read_config_byte(chip->pci, 0x42, &snoop);
+		if (!(snoop & 0x80) && chip->pci->revision == 0x30) {
+			chip->snoop = 0;
+			snd_printdd(SFX "Force to non-snoop mode\n");
+		}
+	}
 
 	/* Clear bits 0-2 of PCI register TCSEL (at offset 0x44)
 	 * TCSEL == Traffic Class Select Register, which sets PCI express QOS
@@ -1102,15 +1168,15 @@ static void azx_init_pci(struct azx *chip)
 	 * we need to enable snoop.
 	 */
 	if (chip->driver_caps & AZX_DCAPS_ATI_SNOOP) {
-		snd_printdd(SFX "Enabling ATI snoop\n");
+		snd_printdd(SFX "Setting ATI snoop: %d\n", azx_snoop(chip));
 		update_pci_byte(chip->pci,
-				ATI_SB450_HDAUDIO_MISC_CNTR2_ADDR, 
-				0x07, ATI_SB450_HDAUDIO_ENABLE_SNOOP);
+				ATI_SB450_HDAUDIO_MISC_CNTR2_ADDR, 0x07,
+				azx_snoop(chip) ? ATI_SB450_HDAUDIO_ENABLE_SNOOP : 0);
 	}
 
 	/* For NVIDIA HDA, enable snoop */
 	if (chip->driver_caps & AZX_DCAPS_NVIDIA_SNOOP) {
-		snd_printdd(SFX "Enabling Nvidia snoop\n");
+		snd_printdd(SFX "Setting Nvidia snoop: %d\n", azx_snoop(chip));
 		update_pci_byte(chip->pci,
 				NVIDIA_HDA_TRANSREG_ADDR,
 				0x0f, NVIDIA_HDA_ENABLE_COHBITS);
@@ -1124,16 +1190,20 @@ static void azx_init_pci(struct azx *chip)
 
 	/* Enable SCH/PCH snoop if needed */
 	if (chip->driver_caps & AZX_DCAPS_SCH_SNOOP) {
+		unsigned short snoop;
 		pci_read_config_word(chip->pci, INTEL_SCH_HDA_DEVC, &snoop);
-		if (snoop & INTEL_SCH_HDA_DEVC_NOSNOOP) {
-			pci_write_config_word(chip->pci, INTEL_SCH_HDA_DEVC,
-				snoop & (~INTEL_SCH_HDA_DEVC_NOSNOOP));
+		if ((!azx_snoop(chip) && !(snoop & INTEL_SCH_HDA_DEVC_NOSNOOP)) ||
+		    (azx_snoop(chip) && (snoop & INTEL_SCH_HDA_DEVC_NOSNOOP))) {
+			snoop &= ~INTEL_SCH_HDA_DEVC_NOSNOOP;
+			if (!azx_snoop(chip))
+				snoop |= INTEL_SCH_HDA_DEVC_NOSNOOP;
+			pci_write_config_word(chip->pci, INTEL_SCH_HDA_DEVC, snoop);
 			pci_read_config_word(chip->pci,
 				INTEL_SCH_HDA_DEVC, &snoop);
-			snd_printdd(SFX "HDA snoop disabled, enabling ... %s\n",
-				(snoop & INTEL_SCH_HDA_DEVC_NOSNOOP)
-				? "Failed" : "OK");
 		}
+		snd_printdd(SFX "SCH snoop: %s\n",
+				(snoop & INTEL_SCH_HDA_DEVC_NOSNOOP)
+				? "Disabled" : "Enabled");
         }
 }
 
@@ -1340,12 +1410,16 @@ static void azx_stream_reset(struct azx *chip, struct azx_dev *azx_dev)
  */
 static int azx_setup_controller(struct azx *chip, struct azx_dev *azx_dev)
 {
+	unsigned int val;
 	/* make sure the run bit is zero for SD */
 	azx_stream_clear(chip, azx_dev);
 	/* program the stream_tag */
-	azx_sd_writel(azx_dev, SD_CTL,
-		      (azx_sd_readl(azx_dev, SD_CTL) & ~SD_CTL_STREAM_TAG_MASK)|
-		      (azx_dev->stream_tag << SD_CTL_STREAM_TAG_SHIFT));
+	val = azx_sd_readl(azx_dev, SD_CTL);
+	val = (val & ~SD_CTL_STREAM_TAG_MASK) |
+		(azx_dev->stream_tag << SD_CTL_STREAM_TAG_SHIFT);
+	if (!azx_snoop(chip))
+		val |= SD_CTL_TRAFFIC_PRIO;
+	azx_sd_writel(azx_dev, SD_CTL, val);
 
 	/* program the length of samples in cyclic buffer */
 	azx_sd_writel(azx_dev, SD_CBL, azx_dev->bufsize);
@@ -1693,19 +1767,30 @@ static int azx_pcm_close(struct snd_pcm_substream *substream)
 static int azx_pcm_hw_params(struct snd_pcm_substream *substream,
 			     struct snd_pcm_hw_params *hw_params)
 {
+	struct azx_pcm *apcm = snd_pcm_substream_chip(substream);
+	struct azx *chip = apcm->chip;
+	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct azx_dev *azx_dev = get_azx_dev(substream);
+	int ret;
 
+	mark_runtime_wc(chip, azx_dev, runtime, false);
 	azx_dev->bufsize = 0;
 	azx_dev->period_bytes = 0;
 	azx_dev->format_val = 0;
-	return snd_pcm_lib_malloc_pages(substream,
+	ret = snd_pcm_lib_malloc_pages(substream,
 					params_buffer_bytes(hw_params));
+	if (ret < 0)
+		return ret;
+	mark_runtime_wc(chip, azx_dev, runtime, true);
+	return ret;
 }
 
 static int azx_pcm_hw_free(struct snd_pcm_substream *substream)
 {
 	struct azx_pcm *apcm = snd_pcm_substream_chip(substream);
 	struct azx_dev *azx_dev = get_azx_dev(substream);
+	struct azx *chip = apcm->chip;
+	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct hda_pcm_stream *hinfo = apcm->hinfo[substream->stream];
 
 	/* reset BDL address */
@@ -1718,6 +1803,7 @@ static int azx_pcm_hw_free(struct snd_pcm_substream *substream)
 
 	snd_hda_codec_cleanup(apcm->codec, hinfo, substream);
 
+	mark_runtime_wc(chip, azx_dev, runtime, false);
 	return snd_pcm_lib_free_pages(substream);
 }
 
@@ -2076,6 +2162,20 @@ static void azx_clear_irq_pending(struct azx *chip)
 	spin_unlock_irq(&chip->reg_lock);
 }
 
+#ifdef CONFIG_X86
+static int azx_pcm_mmap(struct snd_pcm_substream *substream,
+			struct vm_area_struct *area)
+{
+	struct azx_pcm *apcm = snd_pcm_substream_chip(substream);
+	struct azx *chip = apcm->chip;
+	if (!azx_snoop(chip))
+		area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
+	return snd_pcm_lib_default_mmap(substream, area);
+}
+#else
+#define azx_pcm_mmap	NULL
+#endif
+
 static struct snd_pcm_ops azx_pcm_ops = {
 	.open = azx_pcm_open,
 	.close = azx_pcm_close,
@@ -2085,6 +2185,7 @@ static struct snd_pcm_ops azx_pcm_ops = {
 	.prepare = azx_pcm_prepare,
 	.trigger = azx_pcm_trigger,
 	.pointer = azx_pcm_pointer,
+	.mmap = azx_pcm_mmap,
 	.page = snd_pcm_sgbuf_ops_page,
 };
 
@@ -2365,13 +2466,19 @@ static int azx_free(struct azx *chip)
 
 	if (chip->azx_dev) {
 		for (i = 0; i < chip->num_streams; i++)
-			if (chip->azx_dev[i].bdl.area)
+			if (chip->azx_dev[i].bdl.area) {
+				mark_pages_wc(chip, &chip->azx_dev[i].bdl, false);
 				snd_dma_free_pages(&chip->azx_dev[i].bdl);
+			}
 	}
-	if (chip->rb.area)
+	if (chip->rb.area) {
+		mark_pages_wc(chip, &chip->rb, false);
 		snd_dma_free_pages(&chip->rb);
-	if (chip->posbuf.area)
+	}
+	if (chip->posbuf.area) {
+		mark_pages_wc(chip, &chip->posbuf, false);
 		snd_dma_free_pages(&chip->posbuf);
+	}
 	pci_release_regions(chip->pci);
 	pci_disable_device(chip->pci);
 	kfree(chip->azx_dev);
@@ -2566,6 +2673,7 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
 	check_probe_mask(chip, dev);
 
 	chip->single_cmd = single_cmd;
+	chip->snoop = hda_snoop;
 
 	if (bdl_pos_adj[dev] < 0) {
 		switch (chip->driver_type) {
@@ -2693,6 +2801,7 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
 			snd_printk(KERN_ERR SFX "cannot allocate BDL\n");
 			goto errout;
 		}
+		mark_pages_wc(chip, &chip->azx_dev[i].bdl, true);
 	}
 	/* allocate memory for the position buffer */
 	err = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV,
@@ -2702,6 +2811,7 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
 		snd_printk(KERN_ERR SFX "cannot allocate posbuf\n");
 		goto errout;
 	}
+	mark_pages_wc(chip, &chip->posbuf, true);
 	/* allocate CORB/RIRB */
 	err = azx_alloc_cmd_io(chip);
 	if (err < 0)