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Subject[PATCH 1/3] ASoC: amd: use DMA addr rather than CPU pa for audio buffer
Date
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.

Signed-off-by: Vijendar Mukunda <vijendar.mukunda@amd.com>
Tested-by: RAVULAPATI VISHNU VARDHAN RAO <Vishnuvardhanrao.Ravulapati@amd.com>
---
sound/soc/amd/raven/acp3x-pcm-dma.c | 23 +++++++++++------------
1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/sound/soc/amd/raven/acp3x-pcm-dma.c b/sound/soc/amd/raven/acp3x-pcm-dma.c
index a4ade6b..49c4872 100644
--- a/sound/soc/amd/raven/acp3x-pcm-dma.c
+++ b/sound/soc/amd/raven/acp3x-pcm-dma.c
@@ -31,7 +31,7 @@ struct i2s_stream_instance {
u16 num_pages;
u16 channels;
u32 xfer_resolution;
- struct page *pg;
+ dma_addr_t dma_addr;
u64 bytescount;
void __iomem *acp3x_base;
};
@@ -211,11 +211,13 @@ static irqreturn_t i2s_irq_handler(int irq, void *dev_id)
static void config_acp3x_dma(struct i2s_stream_instance *rtd, int direction)
{
u16 page_idx;
- u64 addr;
+ dma_addr_t addr;
u32 low, high, val, acp_fifo_addr;
- struct page *pg = rtd->pg;

- /* 8 scratch registers used to map one 64 bit address */
+ addr = rtd->dma_addr;
+ /* 8 scratch registers used to map one 64 bit address.
+ * For 2 pages (8192 * 2 bytes), it will be 16 registers.
+ */
if (direction == SNDRV_PCM_STREAM_PLAYBACK)
val = 0;
else
@@ -229,7 +231,6 @@ static void config_acp3x_dma(struct i2s_stream_instance *rtd, int direction)

for (page_idx = 0; page_idx < rtd->num_pages; page_idx++) {
/* Load the low address of page int ACP SRAM through SRBM */
- addr = page_to_phys(pg);
low = lower_32_bits(addr);
high = upper_32_bits(addr);

@@ -239,7 +240,7 @@ static void config_acp3x_dma(struct i2s_stream_instance *rtd, int direction)
+ 4);
/* Move to next physically contiguos page */
val += 8;
- pg++;
+ addr += PAGE_SIZE;
}

if (direction == SNDRV_PCM_STREAM_PLAYBACK) {
@@ -340,10 +341,8 @@ static int acp3x_dma_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
int status;
- u64 size;
- struct page *pg;
- struct snd_pcm_runtime *runtime = substream->runtime;
- struct i2s_stream_instance *rtd = runtime->private_data;
+ uint64_t size;
+ struct i2s_stream_instance *rtd = substream->runtime->private_data;

if (!rtd)
return -EINVAL;
@@ -355,8 +354,8 @@ static int acp3x_dma_hw_params(struct snd_pcm_substream *substream,

memset(substream->runtime->dma_area, 0, params_buffer_bytes(params));
pg = virt_to_page(substream->dma_buffer.area);
- if (pg) {
- rtd->pg = pg;
+ if (substream->dma_buffer.area) {
+ rtd->dma_addr = substream->dma_buffer.addr;
rtd->num_pages = (PAGE_ALIGN(size) >> PAGE_SHIFT);
config_acp3x_dma(rtd, substream->stream);
status = 0;
--
2.7.4
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