Re: [alsa-devel] [PATCH 1/2] ASoC: use DMA addr rather than CPU pa for acp_audio_dma

On 05/12/18 4:12 AM, Yu Zhao wrote:

We shouldn't assume CPU physical address we get from page_to_phys() is same as DMA address we get from dma_alloc_coherent(). On x86_64, we won't run into any problem with the assumption when dma_ops is nommu_dma_ops. However, DMA address is IOVA when IOMMU is enabled. And it's most likely different from CPU physical address when AMD IOMMU is not in passthrough mode.

This is really a good fix. We will apply this patch changes for Raven platform also.

Thanks, Vijendar

Signed-off-by: Yu Zhao yuzhao@google.com

sound/soc/amd/acp-pcm-dma.c | 15 +++++---------- sound/soc/amd/acp.h | 2 +- 2 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/sound/soc/amd/acp-pcm-dma.c b/sound/soc/amd/acp-pcm-dma.c index cdebab2f8ce5..fd3db4c37882 100644 --- a/sound/soc/amd/acp-pcm-dma.c +++ b/sound/soc/amd/acp-pcm-dma.c @@ -303,11 +303,10 @@ static void set_acp_to_i2s_dma_descriptors(void __iomem *acp_mmio, u32 size, }

/* Create page table entries in ACP SRAM for the allocated memory */ -static void acp_pte_config(void __iomem *acp_mmio, struct page *pg, +static void acp_pte_config(void __iomem *acp_mmio, dma_addr_t addr, u16 num_of_pages, u32 pte_offset) { u16 page_idx;

• u64 addr; u32 low; u32 high; u32 offset;

@@ -317,7 +316,6 @@ static void acp_pte_config(void __iomem *acp_mmio, struct page *pg, /* Load the low address of page int ACP SRAM through SRBM */ acp_reg_write((offset + (page_idx * 8)), acp_mmio, mmACP_SRBM_Targ_Idx_Addr);

• addr = page_to_phys(pg);
  
  

  low = lower_32_bits(addr); high = upper_32_bits(addr);

@@ -333,7 +331,7 @@ static void acp_pte_config(void __iomem *acp_mmio, struct page *pg, acp_reg_write(high, acp_mmio, mmACP_SRBM_Targ_Idx_Data);

/* Move to next physically contiguos page */

• pg++;
  

• addr += PAGE_SIZE;
  

  } }

@@ -343,7 +341,7 @@ static void config_acp_dma(void __iomem *acp_mmio, { u16 ch_acp_sysmem, ch_acp_i2s;

• acp_pte_config(acp_mmio, rtd->pg, rtd->num_of_pages,

• acp_pte_config(acp_mmio, rtd->dma_addr, rtd->num_of_pages, rtd->pte_offset);

  if (rtd->direction == SNDRV_PCM_STREAM_PLAYBACK) {

@@ -850,7 +848,6 @@ static int acp_dma_hw_params(struct snd_pcm_substream *substream, int status; uint64_t size; u32 val = 0;

• struct page *pg; struct snd_pcm_runtime *runtime; struct audio_substream_data *rtd; struct snd_soc_pcm_runtime *prtd = substream->private_data;

@@ -986,16 +983,14 @@ static int acp_dma_hw_params(struct snd_pcm_substream *substream, return status;

memset(substream->runtime->dma_area, 0, params_buffer_bytes(params));

• pg = virt_to_page(substream->dma_buffer.area);

• if (pg) {

• if (substream->dma_buffer.area) { acp_set_sram_bank_state(rtd->acp_mmio, 0, true); /* Save for runtime private data */

• rtd->pg = pg;
  

• rtd->dma_addr = substream->dma_buffer.addr;
  

  rtd->order = get_order(size);

  /* Fill the page table entries in ACP SRAM */

• rtd->pg = pg;
  

  rtd->size = size; rtd->num_of_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; rtd->direction = substream->stream;

diff --git a/sound/soc/amd/acp.h b/sound/soc/amd/acp.h index dbbb1a85638d..e5ab6c6040a6 100644 --- a/sound/soc/amd/acp.h +++ b/sound/soc/amd/acp.h @@ -123,7 +123,7 @@ enum acp_dma_priority_level { };

struct audio_substream_data {

• struct page *pg;

• dma_addr_t dma_addr; unsigned int order; u16 num_of_pages; u16 i2s_instance;