From: zhang.lyra@gmail.com (Chunyan Zhang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH RFC 2/4] coresight: tmc: set read pointer before dump RAM
Date: Tue, 11 Apr 2017 19:25:30 +0800 [thread overview]
Message-ID: <CAAfSe-vtq6TYaemE5R9H-80uVQ+4eVkKQp3Jom+RvXjFG2r-vQ@mail.gmail.com> (raw)
In-Reply-To: <1491901829-18477-3-git-send-email-leo.yan@linaro.org>
On 11 April 2017 at 17:10, Leo Yan <leo.yan@linaro.org> wrote:
> When dump RAM, we need set read pointer so can make sure every time read
> the consistent content. If the RAM is full by checking status register
> (STS), so set the read pointer to same value with write pointer,
> otherwise set read point to 0 so can read from the start of RAM.
>
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Mike Leach <mike.leach@linaro.org>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Signed-off-by: Leo Yan <leo.yan@linaro.org>
> ---
> drivers/hwtracing/coresight/coresight-tmc-etf.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
> index 6150dac..43cfeaa 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
> @@ -43,10 +43,28 @@ static void tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
>
> static void tmc_etb_dump_hw(struct tmc_drvdata *drvdata)
> {
> + u32 write_ptr, status;
> char *bufp;
> u32 read_data;
> int i;
>
> + write_ptr = readl_relaxed(drvdata->base + TMC_RWP);
Since 'write_ptr' is only used in the below 'if' branch, I would
suggest to move this statement into that.
Regards,
Chunyan
> +
> + /*
> + * Get a hold of the status register and see if a wrap around
> + * has occurred. If so adjust things accordingly.
> + */
> + status = readl_relaxed(drvdata->base + TMC_STS);
> + if (status & TMC_STS_FULL)
> + /* Tell the HW the reading start point */
> + writel_relaxed(write_ptr, drvdata->base + TMC_RRP);
> + else
> + /*
> + * In case this is not first time to read ETB RAM,
> + * always write 0 for reading pointer.
> + */
> + writel_relaxed(0x0, drvdata->base + TMC_RRP);
> +
> bufp = drvdata->buf;
> drvdata->len = 0;
> while (1) {
> --
> 2.7.4
>
next prev parent reply other threads:[~2017-04-11 11:25 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-11 9:10 [PATCH RFC 0/4] coresight: support dump ETB RAM Leo Yan
2017-04-11 9:10 ` [PATCH RFC 1/4] coresight: tmc: check dump buffer is overflow Leo Yan
2017-04-11 9:10 ` [PATCH RFC 2/4] coresight: tmc: set read pointer before dump RAM Leo Yan
2017-04-11 11:25 ` Chunyan Zhang [this message]
2017-04-11 13:46 ` Leo Yan
2017-04-11 9:10 ` [PATCH RFC 3/4] coresight: tmc: dump RAM when device is disabled Leo Yan
2017-04-11 9:10 ` [PATCH RFC 4/4] coresight: tmc: dump RAM for panic Leo Yan
2017-04-20 17:45 ` [PATCH RFC 0/4] coresight: support dump ETB RAM Mathieu Poirier
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