Re: [PATCH 3/3] media: imx-jpeg: Check decoding is ongoing for motion-jpeg

["Ming Qian(OSS)" <ming.qian@oss.nxp.com>]

Hi Frank,

On 2025/3/27 22:41, Frank Li wrote:
> On Thu, Mar 27, 2025 at 10:37:07AM +0800, ming.qian@oss.nxp.com wrote:
>> From: Ming Qian <ming.qian@oss.nxp.com>
>>
>> To support decoding motion-jpeg without DHT, driver will try to decode a
>> pattern jpeg before actual jpeg frame by use of linked descriptors
>> (This is called "repeat mode"), then the DHT in the pattern jpeg can be
>> used for decoding the motion-jpeg.
>>
>> In other words, 2 frame done interrupts will be triggered, driver will
>> ignore the first interrupt, and wait for the second interrupt.
>> If the resolution is small, and the 2 interrupts may be too close,
>> when driver is handling the first interrupt, two frames are done, then
>> driver will fail to wait for the second interrupt.
>>
>> In such case, driver can check whether the decoding is still ongoing,
>> if not, just done the current decoding.
>>
>> Signed-off-by: Ming Qian <ming.qian@oss.nxp.com>
>> ---
>>   .../media/platform/nxp/imx-jpeg/mxc-jpeg-hw.h |  1 +
>>   .../media/platform/nxp/imx-jpeg/mxc-jpeg.c    | 20 ++++++++++++++++++-
>>   2 files changed, 20 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg-hw.h b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg-hw.h
>> index d579c804b047..adb93e977be9 100644
>> --- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg-hw.h
>> +++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg-hw.h
>> @@ -89,6 +89,7 @@
>>   /* SLOT_STATUS fields for slots 0..3 */
>>   #define SLOT_STATUS_FRMDONE			(0x1 << 3)
>>   #define SLOT_STATUS_ENC_CONFIG_ERR		(0x1 << 8)
>> +#define SLOT_STATUS_ONGOING			(0x1 << 31)
>>
>>   /* SLOT_IRQ_EN fields TBD */
>>
>> diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
>> index 45705c606769..e6bb45633a19 100644
>> --- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
>> +++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
>> @@ -910,6 +910,23 @@ static u32 mxc_jpeg_get_plane_size(struct mxc_jpeg_q_data *q_data, u32 plane_no)
>>   	return size;
>>   }
>>
>> +static bool mxc_dec_is_ongoing(struct mxc_jpeg_ctx *ctx)
>> +{
>> +	struct mxc_jpeg_dev *jpeg = ctx->mxc_jpeg;
>> +	u32 curr_desc;
>> +	u32 slot_status;
>> +
>> +	slot_status = readl(jpeg->base_reg + MXC_SLOT_OFFSET(ctx->slot, SLOT_STATUS));
>> +	curr_desc = readl(jpeg->base_reg + MXC_SLOT_OFFSET(ctx->slot, SLOT_CUR_DESCPT_PTR));
>> +
>> +	if (curr_desc == jpeg->slot_data.cfg_desc_handle)
>> +		return true;
>> +	if (slot_status & SLOT_STATUS_ONGOING)
>> +		return true;
>> +
>> +	return false;
>> +}
>> +
>>   static irqreturn_t mxc_jpeg_dec_irq(int irq, void *priv)
>>   {
>>   	struct mxc_jpeg_dev *jpeg = priv;
>> @@ -979,7 +996,8 @@ static irqreturn_t mxc_jpeg_dec_irq(int irq, void *priv)
>>   		mxc_jpeg_enc_mode_go(dev, reg, mxc_jpeg_is_extended_sequential(q_data->fmt));
>>   		goto job_unlock;
>>   	}
>> -	if (jpeg->mode == MXC_JPEG_DECODE && jpeg_src_buf->dht_needed) {
>> +	if (jpeg->mode == MXC_JPEG_DECODE && jpeg_src_buf->dht_needed &&
>> +	    mxc_dec_is_ongoing(ctx)) {
> 
> what happen if hardware completed just after you call mxc_dec_is_ongoing(),
> any thing will be missed?

The interrupt status is cleared before the ongoing check,
so if hardware complete after mxc_dec_is_ongoing(),
a new interrupt is triggered, driver will finish the decoding
in the next irq().It's the same normal process as before.

Thanks,
Ming

> 
> Frank
> 
>>   		jpeg_src_buf->dht_needed = false;
>>   		dev_dbg(dev, "Decoder DHT cfg finished. Start decoding...\n");
>>   		goto job_unlock;
>> --
>> 2.43.0-rc1
>>