[v1] dmaengine: qcom: bam_dma: Avoid writing unavailable register

[PATCH] dmaengine: qcom: bam_dma: Avoid writing unavailable register

Posted by Md Sadre Alam 1 year, 2 months ago

Avoid writing unavailable register in BAM-Lite mode.
BAM_DESC_CNT_TRSHLD register is unavailable in BAM-Lite
mode. Its only available in BAM-NDP mode. So avoid writing
this register for clients who is using BAM-Lite mode.

Signed-off-by: Md Sadre Alam <quic_mdalam@quicinc.com>
---
 drivers/dma/qcom/bam_dma.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index d43a881e43b9..13a08c03746b 100644
--- a/drivers/dma/qcom/bam_dma.c
+++ b/drivers/dma/qcom/bam_dma.c
@@ -59,6 +59,9 @@ struct bam_desc_hw {
 #define DESC_FLAG_NWD BIT(12)
 #define DESC_FLAG_CMD BIT(11)
 
+#define BAM_LITE	0x13
+#define BAM_NDP		0x20
+
 struct bam_async_desc {
 	struct virt_dma_desc vd;
 
@@ -398,6 +401,7 @@ struct bam_device {
 
 	/* dma start transaction tasklet */
 	struct tasklet_struct task;
+	u32 bam_revision;
 };
 
 /**
@@ -441,8 +445,9 @@ static void bam_reset(struct bam_device *bdev)
 	writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));
 
 	/* set descriptor threshold, start with 4 bytes */
-	writel_relaxed(DEFAULT_CNT_THRSHLD,
-			bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
+	if (bdev->bam_revision >= BAM_LITE && bdev->bam_revision < BAM_NDP)
+		writel_relaxed(DEFAULT_CNT_THRSHLD,
+			       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
 
 	/* Enable default set of h/w workarounds, ie all except BAM_FULL_PIPE */
 	writel_relaxed(BAM_CNFG_BITS_DEFAULT, bam_addr(bdev, 0, BAM_CNFG_BITS));
@@ -1000,9 +1005,9 @@ static void bam_apply_new_config(struct bam_chan *bchan,
 			maxburst = bchan->slave.src_maxburst;
 		else
 			maxburst = bchan->slave.dst_maxburst;
-
-		writel_relaxed(maxburst,
-			       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
+		if (bdev->bam_revision >= BAM_LITE && bdev->bam_revision < BAM_NDP)
+			writel_relaxed(maxburst,
+				       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
 	}
 
 	bchan->reconfigure = 0;
@@ -1192,10 +1197,11 @@ static int bam_init(struct bam_device *bdev)
 	u32 val;
 
 	/* read revision and configuration information */
-	if (!bdev->num_ees) {
-		val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION));
+	val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION));
+	if (!bdev->num_ees)
 		bdev->num_ees = (val >> NUM_EES_SHIFT) & NUM_EES_MASK;
-	}
+
+	bdev->bam_revision = val & 0xff;
 
 	/* check that configured EE is within range */
 	if (bdev->ee >= bdev->num_ees)
-- 
2.34.1

Re: [PATCH] dmaengine: qcom: bam_dma: Avoid writing unavailable register

Posted by Varadarajan Narayanan 1 year, 2 months ago

On Fri, Nov 22, 2024 at 12:46:49PM +0530, Md Sadre Alam wrote:
> Avoid writing unavailable register in BAM-Lite mode.
> BAM_DESC_CNT_TRSHLD register is unavailable in BAM-Lite
> mode. Its only available in BAM-NDP mode. So avoid writing
> this register for clients who is using BAM-Lite mode.
>
> Signed-off-by: Md Sadre Alam <quic_mdalam@quicinc.com>
> ---
>  drivers/dma/qcom/bam_dma.c | 22 ++++++++++++++--------
>  1 file changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
> index d43a881e43b9..13a08c03746b 100644
> --- a/drivers/dma/qcom/bam_dma.c
> +++ b/drivers/dma/qcom/bam_dma.c
> @@ -59,6 +59,9 @@ struct bam_desc_hw {
>  #define DESC_FLAG_NWD BIT(12)
>  #define DESC_FLAG_CMD BIT(11)
>
> +#define BAM_LITE	0x13
> +#define BAM_NDP		0x20
> +
>  struct bam_async_desc {
>  	struct virt_dma_desc vd;
>
> @@ -398,6 +401,7 @@ struct bam_device {
>
>  	/* dma start transaction tasklet */
>  	struct tasklet_struct task;
> +	u32 bam_revision;
>  };
>
>  /**
> @@ -441,8 +445,9 @@ static void bam_reset(struct bam_device *bdev)
>  	writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));
>
>  	/* set descriptor threshold, start with 4 bytes */
> -	writel_relaxed(DEFAULT_CNT_THRSHLD,
> -			bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
> +	if (bdev->bam_revision >= BAM_LITE && bdev->bam_revision < BAM_NDP)
> +		writel_relaxed(DEFAULT_CNT_THRSHLD,
> +			       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
>
>  	/* Enable default set of h/w workarounds, ie all except BAM_FULL_PIPE */
>  	writel_relaxed(BAM_CNFG_BITS_DEFAULT, bam_addr(bdev, 0, BAM_CNFG_BITS));
> @@ -1000,9 +1005,9 @@ static void bam_apply_new_config(struct bam_chan *bchan,
>  			maxburst = bchan->slave.src_maxburst;
>  		else
>  			maxburst = bchan->slave.dst_maxburst;
> -
> -		writel_relaxed(maxburst,
> -			       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
> +		if (bdev->bam_revision >= BAM_LITE && bdev->bam_revision < BAM_NDP)
> +			writel_relaxed(maxburst,
> +				       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
>  	}
>
>  	bchan->reconfigure = 0;
> @@ -1192,10 +1197,11 @@ static int bam_init(struct bam_device *bdev)
>  	u32 val;
>
>  	/* read revision and configuration information */
> -	if (!bdev->num_ees) {
> -		val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION));
> +	val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION));
> +	if (!bdev->num_ees)
>  		bdev->num_ees = (val >> NUM_EES_SHIFT) & NUM_EES_MASK;
> -	}
> +
> +	bdev->bam_revision = val & 0xff;

Use REVISION_MASK instead of 0xff

-Varada

>  	/* check that configured EE is within range */
>  	if (bdev->ee >= bdev->num_ees)
> --
> 2.34.1
>

Re: [PATCH] dmaengine: qcom: bam_dma: Avoid writing unavailable register

Posted by Md Sadre Alam 1 year, 2 months ago


On 11/23/2024 10:06 AM, Varadarajan Narayanan wrote:
> On Fri, Nov 22, 2024 at 12:46:49PM +0530, Md Sadre Alam wrote:
>> Avoid writing unavailable register in BAM-Lite mode.
>> BAM_DESC_CNT_TRSHLD register is unavailable in BAM-Lite
>> mode. Its only available in BAM-NDP mode. So avoid writing
>> this register for clients who is using BAM-Lite mode.
>>
>> Signed-off-by: Md Sadre Alam <quic_mdalam@quicinc.com>
>> ---
>>   drivers/dma/qcom/bam_dma.c | 22 ++++++++++++++--------
>>   1 file changed, 14 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
>> index d43a881e43b9..13a08c03746b 100644
>> --- a/drivers/dma/qcom/bam_dma.c
>> +++ b/drivers/dma/qcom/bam_dma.c
>> @@ -59,6 +59,9 @@ struct bam_desc_hw {
>>   #define DESC_FLAG_NWD BIT(12)
>>   #define DESC_FLAG_CMD BIT(11)
>>
>> +#define BAM_LITE	0x13
>> +#define BAM_NDP		0x20
>> +
>>   struct bam_async_desc {
>>   	struct virt_dma_desc vd;
>>
>> @@ -398,6 +401,7 @@ struct bam_device {
>>
>>   	/* dma start transaction tasklet */
>>   	struct tasklet_struct task;
>> +	u32 bam_revision;
>>   };
>>
>>   /**
>> @@ -441,8 +445,9 @@ static void bam_reset(struct bam_device *bdev)
>>   	writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));
>>
>>   	/* set descriptor threshold, start with 4 bytes */
>> -	writel_relaxed(DEFAULT_CNT_THRSHLD,
>> -			bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
>> +	if (bdev->bam_revision >= BAM_LITE && bdev->bam_revision < BAM_NDP)
>> +		writel_relaxed(DEFAULT_CNT_THRSHLD,
>> +			       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
>>
>>   	/* Enable default set of h/w workarounds, ie all except BAM_FULL_PIPE */
>>   	writel_relaxed(BAM_CNFG_BITS_DEFAULT, bam_addr(bdev, 0, BAM_CNFG_BITS));
>> @@ -1000,9 +1005,9 @@ static void bam_apply_new_config(struct bam_chan *bchan,
>>   			maxburst = bchan->slave.src_maxburst;
>>   		else
>>   			maxburst = bchan->slave.dst_maxburst;
>> -
>> -		writel_relaxed(maxburst,
>> -			       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
>> +		if (bdev->bam_revision >= BAM_LITE && bdev->bam_revision < BAM_NDP)
>> +			writel_relaxed(maxburst,
>> +				       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
>>   	}
>>
>>   	bchan->reconfigure = 0;
>> @@ -1192,10 +1197,11 @@ static int bam_init(struct bam_device *bdev)
>>   	u32 val;
>>
>>   	/* read revision and configuration information */
>> -	if (!bdev->num_ees) {
>> -		val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION));
>> +	val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION));
>> +	if (!bdev->num_ees)
>>   		bdev->num_ees = (val >> NUM_EES_SHIFT) & NUM_EES_MASK;
>> -	}
>> +
>> +	bdev->bam_revision = val & 0xff;
> 
> Use REVISION_MASK instead of 0xff
Ok
> 
> -Varada
> 
>>   	/* check that configured EE is within range */
>>   	if (bdev->ee >= bdev->num_ees)
>> --
>> 2.34.1
>>