linux-kernel - Re: [PATCH 2/2] coresight: catu: Correct memory sync ranges in catu mode

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Date:   Mon, 12 Jul 2021 11:26:52 +0100
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Leo Yan <leo.yan@...aro.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Mike Leach <mike.leach@...aro.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] coresight: catu: Correct memory sync ranges in catu
 mode

Hi Leo,

On 10/07/2021 08:02, Leo Yan wrote:
> Current code misses to handle the case for the trace wrapping around,
> thus it fails to sync the complete memory ranges in catu mode.
> 

Similar to the tmc-sg, the infrastructure take care of wrapping the page
indices to sync the correct memory.

Suzuki


> This patch corrects the memory sync ranges, when detects the wrapping
> around case, it splits into two chunks: one chunk is the tail of the
> buffer and another chunk is from the start of the buffer after wrapping
> around.
> 
> Signed-off-by: Leo Yan <leo.yan@...aro.org>
> ---
>   drivers/hwtracing/coresight/coresight-catu.c | 19 ++++++++++++++++++-
>   1 file changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c
> index e0740c6dbd54..634af451f0d3 100644
> --- a/drivers/hwtracing/coresight/coresight-catu.c
> +++ b/drivers/hwtracing/coresight/coresight-catu.c
> @@ -323,7 +323,24 @@ static void catu_sync_etr_buf(struct etr_buf *etr_buf, u64 rrp, u64 rwp)
>   	}
>   
>   	etr_buf->offset = r_offset;
> -	tmc_sg_table_sync_data_range(catu_table, r_offset, etr_buf->len);
> +
> +	if (r_offset + etr_buf->len > etr_buf->size) {
> +		int len1, len2;
> +
> +		/*
> +		 * If trace data is wrapped around, sync AUX bounce buffer
> +		 * for two chunks: "len1" is for the trace date length at
> +		 * the tail of bounce buffer, and "len2" is the length from
> +		 * the start of the buffer after wrapping around.
> +		 */
> +		len1 = etr_buf->size - r_offset;
> +		len2 = etr_buf->len - len1;
> +		tmc_sg_table_sync_data_range(catu_table, r_offset, len1);
> +		tmc_sg_table_sync_data_range(catu_table, 0, len2);
> +	} else {
> +		tmc_sg_table_sync_data_range(catu_table, r_offset,
> +					     etr_buf->len);
> +	}
>   }
>   
>   static int catu_alloc_etr_buf(struct tmc_drvdata *tmc_drvdata,
>