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Subject[PATCH] ASoC: AMD: Fix race condition between register access
Date
During simultaneous running of playback and capture, we
got hit by incorrect value write on common register. This was due
to race condition between 2 streams.
Fixing this by locking the common register access.

Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>
---
sound/soc/amd/acp-pcm-dma.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)

diff --git a/sound/soc/amd/acp-pcm-dma.c b/sound/soc/amd/acp-pcm-dma.c
index 0ac4b5b..993a7db 100644
--- a/sound/soc/amd/acp-pcm-dma.c
+++ b/sound/soc/amd/acp-pcm-dma.c
@@ -121,6 +121,9 @@
.periods_max = CAPTURE_MAX_NUM_PERIODS,
};

+/* Lock to protect access to registers */
+static DEFINE_SPINLOCK(lock);
+
static u32 acp_reg_read(void __iomem *acp_mmio, u32 reg)
{
return readl(acp_mmio + (reg * 4));
@@ -168,9 +171,12 @@ static void config_dma_descriptor_in_sram(void __iomem *acp_mmio,
acp_dma_dscr_transfer_t *descr_info)
{
u32 sram_offset;
+ unsigned long flags;

sram_offset = (descr_idx * sizeof(acp_dma_dscr_transfer_t));

+ spin_lock_irqsave(&lock, flags);
+
/* program the source base address. */
acp_reg_write(sram_offset, acp_mmio, mmACP_SRBM_Targ_Idx_Addr);
acp_reg_write(descr_info->src, acp_mmio, mmACP_SRBM_Targ_Idx_Data);
@@ -181,6 +187,8 @@ static void config_dma_descriptor_in_sram(void __iomem *acp_mmio,
/* program the number of bytes to be transferred for this descriptor. */
acp_reg_write(sram_offset + 8, acp_mmio, mmACP_SRBM_Targ_Idx_Addr);
acp_reg_write(descr_info->xfer_val, acp_mmio, mmACP_SRBM_Targ_Idx_Data);
+
+ spin_unlock_irqrestore(&lock, flags);
}

static void pre_config_reset(void __iomem *acp_mmio, u16 ch_num)
@@ -309,8 +317,12 @@ static void acp_pte_config(void __iomem *acp_mmio, struct page *pg,
u32 low;
u32 high;
u32 offset;
+ unsigned long flags;

offset = ACP_DAGB_GRP_SRBM_SRAM_BASE_OFFSET + (pte_offset * 8);
+
+ spin_lock_irqsave(&lock, flags);
+
for (page_idx = 0; page_idx < (num_of_pages); page_idx++) {
/* Load the low address of page int ACP SRAM through SRBM */
acp_reg_write((offset + (page_idx * 8)),
@@ -333,6 +345,8 @@ static void acp_pte_config(void __iomem *acp_mmio, struct page *pg,
/* Move to next physically contiguos page */
pg++;
}
+
+ spin_unlock_irqrestore(&lock, flags);
}

static void config_acp_dma(void __iomem *acp_mmio,
@@ -367,6 +381,7 @@ static void acp_dma_cap_channel_enable(void __iomem *acp_mmio,
u16 cap_channel)
{
u32 val, ch_reg, imr_reg, res_reg;
+ unsigned long flags;

switch (cap_channel) {
case CAP_CHANNEL1:
@@ -381,6 +396,8 @@ static void acp_dma_cap_channel_enable(void __iomem *acp_mmio,
imr_reg = mmACP_I2SMICSP_IMR0;
break;
}
+ spin_lock_irqsave(&lock, flags);
+
val = acp_reg_read(acp_mmio,
mmACP_I2S_16BIT_RESOLUTION_EN);
if (val & ACP_I2S_MIC_16BIT_RESOLUTION_EN) {
@@ -393,12 +410,15 @@ static void acp_dma_cap_channel_enable(void __iomem *acp_mmio,
val &= ~ACP_I2SMICSP_IMR1__I2SMICSP_RXFOM_MASK;
acp_reg_write(val, acp_mmio, imr_reg);
acp_reg_write(0x1, acp_mmio, ch_reg);
+
+ spin_unlock_irqrestore(&lock, flags);
}

static void acp_dma_cap_channel_disable(void __iomem *acp_mmio,
u16 cap_channel)
{
u32 val, ch_reg, imr_reg;
+ unsigned long flags;

switch (cap_channel) {
case CAP_CHANNEL1:
@@ -411,11 +431,15 @@ static void acp_dma_cap_channel_disable(void __iomem *acp_mmio,
ch_reg = mmACP_I2SMICSP_RER0;
break;
}
+ spin_lock_irqsave(&lock, flags);
+
val = acp_reg_read(acp_mmio, imr_reg);
val |= ACP_I2SMICSP_IMR1__I2SMICSP_RXDAM_MASK;
val |= ACP_I2SMICSP_IMR1__I2SMICSP_RXFOM_MASK;
acp_reg_write(val, acp_mmio, imr_reg);
acp_reg_write(0x0, acp_mmio, ch_reg);
+
+ spin_unlock_irqrestore(&lock, flags);
}

/* Start a given DMA channel transfer */
@@ -847,6 +871,7 @@ static int acp_dma_hw_params(struct snd_pcm_substream *substream,
int status;
uint64_t size;
u32 val = 0;
+ unsigned long flags;
struct page *pg;
struct snd_pcm_runtime *runtime;
struct audio_substream_data *rtd;
@@ -870,6 +895,8 @@ static int acp_dma_hw_params(struct snd_pcm_substream *substream,
}
}
if (adata->asic_type == CHIP_STONEY) {
+ spin_lock_irqsave(&lock, flags);
+
val = acp_reg_read(adata->acp_mmio,
mmACP_I2S_16BIT_RESOLUTION_EN);
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
@@ -893,6 +920,8 @@ static int acp_dma_hw_params(struct snd_pcm_substream *substream,
}
acp_reg_write(val, adata->acp_mmio,
mmACP_I2S_16BIT_RESOLUTION_EN);
+
+ spin_unlock_irqrestore(&lock, flags);
}

if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
--
1.9.1
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