[v3] dmaengine: qcom: bam_dma: Avoid writing unavailable register

[PATCH v3] dmaengine: qcom: bam_dma: Avoid writing unavailable register

Posted by Md Sadre Alam 1 year 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 only write
this register for clients who is using BAM-NDP.

Signed-off-by: Md Sadre Alam <quic_mdalam@quicinc.com>
---

Change in [v3]

* Removed BAM_LITE macro

* Updated commit message

* Adjusted if condition check

* Renamed BAM-NDP macro to BAM_NDP_REVISION_START and 
  BAM_NDP_REVISION_END

Change in [v2]

* Replace 0xff with REVISION_MASK in the statement
  bdev->bam_revision = val & REVISION_MASK

Change in [v1]

* Added initial patch

 drivers/dma/qcom/bam_dma.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index d43a881e43b9..a00dd0331ff5 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_NDP_REVISION_START	0x20
+#define BAM_NDP_REVISION_END	0x27
+
 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 +445,10 @@ 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_NDP_REVISION_START &&
+	    bdev->bam_revision <= BAM_NDP_REVISION_END)
+		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 +1006,10 @@ 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_NDP_REVISION_START &&
+		    bdev->bam_revision <= BAM_NDP_REVISION_END)
+			writel_relaxed(maxburst,
+				       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
 	}
 
 	bchan->reconfigure = 0;
@@ -1192,10 +1199,11 @@ 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 & REVISION_MASK;
 
 	/* check that configured EE is within range */
 	if (bdev->ee >= bdev->num_ees)
-- 
2.34.1

Re: [PATCH v3] dmaengine: qcom: bam_dma: Avoid writing unavailable register

Posted by Manikanta Mylavarapu 1 year ago


On 12/9/2024 1:01 PM, 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 only write
> this register for clients who is using BAM-NDP.
> 
> Signed-off-by: Md Sadre Alam <quic_mdalam@quicinc.com>
> ---
> 
> Change in [v3]
> 
> * Removed BAM_LITE macro
> 
> * Updated commit message
> 
> * Adjusted if condition check
> 
> * Renamed BAM-NDP macro to BAM_NDP_REVISION_START and 
>   BAM_NDP_REVISION_END
> 
> Change in [v2]
> 
> * Replace 0xff with REVISION_MASK in the statement
>   bdev->bam_revision = val & REVISION_MASK
> 
> Change in [v1]
> 
> * Added initial patch
> 
>  drivers/dma/qcom/bam_dma.c | 24 ++++++++++++++++--------
>  1 file changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
> index d43a881e43b9..a00dd0331ff5 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_NDP_REVISION_START	0x20
> +#define BAM_NDP_REVISION_END	0x27
> +
>  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 +445,10 @@ 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_NDP_REVISION_START &&
> +	    bdev->bam_revision <= BAM_NDP_REVISION_END)

Please use in_range().

> +		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 +1006,10 @@ 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_NDP_REVISION_START &&
> +		    bdev->bam_revision <= BAM_NDP_REVISION_END)

Please use in_range().

Thanks & Regards,
Manikanta.

Re: [PATCH v3] dmaengine: qcom: bam_dma: Avoid writing unavailable register

Posted by Md Sadre Alam 1 year ago


On 12/9/2024 4:05 PM, Manikanta Mylavarapu wrote:
> 
> 
> On 12/9/2024 1:01 PM, 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 only write
>> this register for clients who is using BAM-NDP.
>>
>> Signed-off-by: Md Sadre Alam <quic_mdalam@quicinc.com>
>> ---
>>
>> Change in [v3]
>>
>> * Removed BAM_LITE macro
>>
>> * Updated commit message
>>
>> * Adjusted if condition check
>>
>> * Renamed BAM-NDP macro to BAM_NDP_REVISION_START and
>>    BAM_NDP_REVISION_END
>>
>> Change in [v2]
>>
>> * Replace 0xff with REVISION_MASK in the statement
>>    bdev->bam_revision = val & REVISION_MASK
>>
>> Change in [v1]
>>
>> * Added initial patch
>>
>>   drivers/dma/qcom/bam_dma.c | 24 ++++++++++++++++--------
>>   1 file changed, 16 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
>> index d43a881e43b9..a00dd0331ff5 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_NDP_REVISION_START	0x20
>> +#define BAM_NDP_REVISION_END	0x27
>> +
>>   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 +445,10 @@ 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_NDP_REVISION_START &&
>> +	    bdev->bam_revision <= BAM_NDP_REVISION_END)
> 
> Please use in_range().
Ok
> 
>> +		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 +1006,10 @@ 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_NDP_REVISION_START &&
>> +		    bdev->bam_revision <= BAM_NDP_REVISION_END)
> 
> Please use in_range().
Ok
> 
> Thanks & Regards,
> Manikanta.
>