Re: [PATCH v3 06/13] media: ti: j721e-csi2rx: get number of contexts from device tree

[Rishikesh Donadkar <r-donadkar@ti.com>]

On 21/04/25 18:50, Laurent Pinchart wrote:
> Hi Rishikesh,
>
> Thank you for the patch.


Hi Laurent,

Thank you for the review !

>
> On Thu, Apr 17, 2025 at 12:25:47PM +0530, Rishikesh Donadkar wrote:
>> From: Pratyush Yadav <p.yadav@ti.com>
>>
>> Different platforms that use this driver might have different number of
>> DMA channels allocated for CSI. So only as many DMA contexts can be used
>> as the number of DMA channels available. Get the number of channels
>> provided via device tree and only configure that many contexts, and
>> hence only that many pads.
>>
>> Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
>> Co-developed-by: Jai Luthra <j-luthra@ti.com>
>> Signed-off-by: Jai Luthra <j-luthra@ti.com>
>> Signed-off-by: Rishikesh Donadkar <r-donadkar@ti.com>
>> ---
>>   .../platform/ti/j721e-csi2rx/j721e-csi2rx.c   | 41 ++++++++++++++-----
>>   1 file changed, 30 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c b/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c
>> index ea7e331e872af..e85d04d7c2ff9 100644
>> --- a/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c
>> +++ b/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c
>> @@ -40,7 +40,7 @@
>>   #define SHIM_PSI_CFG0_DST_TAG		GENMASK(31, 16)
>>   
>>   #define PSIL_WORD_SIZE_BYTES		16
>> -#define TI_CSI2RX_NUM_CTX		1
>> +#define TI_CSI2RX_MAX_CTX		32
>>   
>>   /*
>>    * There are no hard limits on the width or height. The DMA engine can handle
>> @@ -53,8 +53,8 @@
>>   
>>   #define TI_CSI2RX_PAD_SINK		0
>>   #define TI_CSI2RX_PAD_FIRST_SOURCE	1
>> -#define TI_CSI2RX_NUM_SOURCE_PADS	1
>> -#define TI_CSI2RX_NUM_PADS		(1 + TI_CSI2RX_NUM_SOURCE_PADS)
>> +#define TI_CSI2RX_MAX_SOURCE_PADS	TI_CSI2RX_MAX_CTX
>> +#define TI_CSI2RX_MAX_PADS		(1 + TI_CSI2RX_MAX_SOURCE_PADS)
>>   
>>   #define DRAIN_TIMEOUT_MS		50
>>   #define DRAIN_BUFFER_SIZE		SZ_32K
>> @@ -112,14 +112,15 @@ struct ti_csi2rx_dev {
>>   	void __iomem			*shim;
>>   	struct mutex			mutex; /* To serialize ioctls. */
>>   	unsigned int			enable_count;
>> +	unsigned int			num_ctx;
>>   	struct v4l2_device		v4l2_dev;
>>   	struct media_device		mdev;
>>   	struct media_pipeline		pipe;
>> -	struct media_pad		pads[TI_CSI2RX_NUM_PADS];
>> +	struct media_pad		pads[TI_CSI2RX_MAX_PADS];
>>   	struct v4l2_async_notifier	notifier;
>>   	struct v4l2_subdev		*source;
>>   	struct v4l2_subdev		subdev;
>> -	struct ti_csi2rx_ctx		ctx[TI_CSI2RX_NUM_CTX];
>> +	struct ti_csi2rx_ctx		ctx[TI_CSI2RX_MAX_CTX];
>>   	/* Buffer to drain stale data from PSI-L endpoint */
>>   	struct {
>>   		void			*vaddr;
>> @@ -449,7 +450,7 @@ static int csi_async_notifier_complete(struct v4l2_async_notifier *notifier)
>>   		return ret;
>>   
>>   	/* Create and link video nodes for all DMA contexts */
>> -	for (i = 0; i < TI_CSI2RX_NUM_CTX; i++) {
>> +	for (i = 0; i < csi->num_ctx; i++) {
>>   		struct ti_csi2rx_ctx *ctx = &csi->ctx[i];
>>   		struct video_device *vdev = &ctx->vdev;
>>   
>> @@ -1212,10 +1213,11 @@ static int ti_csi2rx_v4l2_init(struct ti_csi2rx_dev *csi)
>>   	csi->pads[TI_CSI2RX_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
>>   
>>   	for (unsigned int i = TI_CSI2RX_PAD_FIRST_SOURCE;
>> -	     i < TI_CSI2RX_NUM_PADS; i++)
>> +	     i < TI_CSI2RX_PAD_FIRST_SOURCE + csi->num_ctx; i++)
>>   		csi->pads[i].flags = MEDIA_PAD_FL_SOURCE;
>>   
>> -	ret = media_entity_pads_init(&sd->entity, ARRAY_SIZE(csi->pads),
>> +	ret = media_entity_pads_init(&sd->entity,
>> +				     TI_CSI2RX_PAD_FIRST_SOURCE + csi->num_ctx,
>>   				     csi->pads);
>>   	if (ret)
>>   		goto unregister_media;
>> @@ -1301,8 +1303,9 @@ static int ti_csi2rx_init_ctx(struct ti_csi2rx_ctx *ctx)
>>   
>>   static int ti_csi2rx_probe(struct platform_device *pdev)
>>   {
>> +	struct device_node *np = pdev->dev.of_node;
>>   	struct ti_csi2rx_dev *csi;
>> -	int ret, i;
>> +	int ret, i, count;
>>   
>>   	csi = devm_kzalloc(&pdev->dev, sizeof(*csi), GFP_KERNEL);
>>   	if (!csi)
>> @@ -1324,13 +1327,29 @@ static int ti_csi2rx_probe(struct platform_device *pdev)
>>   	if (!csi->drain.vaddr)
>>   		return -ENOMEM;
>>   
>> +	/* Only use as many contexts as the number of DMA channels allocated. */
>> +	count = of_property_count_strings(np, "dma-names");
>> +	if (count < 0) {
>> +		dev_err(csi->dev, "Failed to get DMA channel count: %d\n",
>> +			count);
>> +		return count;
> You're leaking the drain buffer.


Oops. Will fix in the next revision


>
>> +	}
>> +
>> +	csi->num_ctx = count;
>> +	if (csi->num_ctx > TI_CSI2RX_MAX_CTX) {
>> +		dev_warn(csi->dev,
>> +			 "%u DMA channels passed. Maximum is %u. Ignoring the rest.\n",
>> +			 csi->num_ctx, TI_CSI2RX_MAX_CTX);
> I'd rather turn this into a hard error and get the device trees fixed.


Right, will do that in the next revision.


>
>> +		csi->num_ctx = TI_CSI2RX_MAX_CTX;
>> +	}
>> +
>>   	mutex_init(&csi->mutex);
>>   
>>   	ret = ti_csi2rx_v4l2_init(csi);
>>   	if (ret)
>>   		goto err_v4l2;
>>   
>> -	for (i = 0; i < TI_CSI2RX_NUM_CTX; i++) {
>> +	for (i = 0; i < csi->num_ctx; i++) {
>>   		csi->ctx[i].idx = i;
>>   		csi->ctx[i].csi = csi;
>>   		ret = ti_csi2rx_init_ctx(&csi->ctx[i]);
>> @@ -1369,7 +1388,7 @@ static void ti_csi2rx_remove(struct platform_device *pdev)
>>   	struct ti_csi2rx_dev *csi = platform_get_drvdata(pdev);
>>   	unsigned int i;
>>   
>> -	for (i = 0; i < TI_CSI2RX_NUM_CTX; i++)
>> +	for (i = 0; i < csi->num_ctx; i++)
>>   		ti_csi2rx_cleanup_ctx(&csi->ctx[i]);
>>   
>>   	ti_csi2rx_cleanup_notifier(csi);

Regards,

Rishi