ALSA: memalloc: Fix pgprot for WC mmap on x86

We have a special handling of WC pages on x86, and it's currently
specific to HD-audio.  The last forgotten piece was the pgprot setup
for the mmap with WC pages.

This patch moves the pgprot setup for WC pages from HD-audio-specific
mmap callback to the common helper code.  It allows us to remove the
superfluous mmap callback in HD-audio and its prepare_mmap
redirection.

Link: https://lore.kernel.org/r/20210804061329.29265-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/memalloc.c

@@ -407,6 +407,10 @@ static void snd_dma_dev_free(struct snd_dma_buffer *dmab)
 static int snd_dma_dev_mmap(struct snd_dma_buffer *dmab,
 			    struct vm_area_struct *area)
 {
+#ifdef CONFIG_X86
+	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC)
+		area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
+#endif
 	return dma_mmap_coherent(dmab->dev.dev, area,
 				 dmab->area, dmab->addr, dmab->bytes);
 }

sound/pci/hda/hda_controller.c

@@ -669,16 +669,6 @@ static int azx_pcm_open(struct snd_pcm_substream *substream)
 	return err;
 }
 
-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 (chip->ops->pcm_mmap_prepare)
-		chip->ops->pcm_mmap_prepare(substream, area);
-	return snd_pcm_lib_default_mmap(substream, area);
-}
-
 static const struct snd_pcm_ops azx_pcm_ops = {
 	.open = azx_pcm_open,
 	.close = azx_pcm_close,
@@ -688,7 +678,6 @@ static const struct snd_pcm_ops azx_pcm_ops = {
 	.trigger = azx_pcm_trigger,
 	.pointer = azx_pcm_pointer,
 	.get_time_info =  azx_get_time_info,
-	.mmap = azx_pcm_mmap,
 };
 
 static void azx_pcm_free(struct snd_pcm *pcm)

sound/pci/hda/hda_controller.h

@@ -74,8 +74,6 @@ struct azx;
 struct hda_controller_ops {
 	/* Disable msi if supported, PCI only */
 	int (*disable_msi_reset_irq)(struct azx *);
-	void (*pcm_mmap_prepare)(struct snd_pcm_substream *substream,
-				 struct vm_area_struct *area);
 	/* Check if current position is acceptable */
 	int (*position_check)(struct azx *chip, struct azx_dev *azx_dev);
 	/* enable/disable the link power */

sound/pci/hda/hda_intel.c

@@ -2037,17 +2037,6 @@ static int disable_msi_reset_irq(struct azx *chip)
 	return 0;
 }
 
-static void pcm_mmap_prepare(struct snd_pcm_substream *substream,
-			     struct vm_area_struct *area)
-{
-#ifdef CONFIG_X86
-	struct azx_pcm *apcm = snd_pcm_substream_chip(substream);
-	struct azx *chip = apcm->chip;
-	if (chip->uc_buffer)
-		area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
-#endif
-}
-
 /* Denylist for skipping the whole probe:
  * some HD-audio PCI entries are exposed without any codecs, and such devices
  * should be ignored from the beginning.
@@ -2061,7 +2050,6 @@ static const struct pci_device_id driver_denylist[] = {
 
 static const struct hda_controller_ops pci_hda_ops = {
 	.disable_msi_reset_irq = disable_msi_reset_irq,
-	.pcm_mmap_prepare = pcm_mmap_prepare,
 	.position_check = azx_position_check,
 };