linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: Suzuki.Poulose@arm.com (Suzuki K Poulose)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V2 06/15] coresight: tmc: making prepare/unprepare functions generic
Date: Tue, 19 Apr 2016 16:32:38 +0100	[thread overview]
Message-ID: <57164F96.7000909@arm.com> (raw)
In-Reply-To: <CANLsYkzizZtY=Mvh-Ko619Rc5GRCj1VVxracKgWVhNx=jFwqBw@mail.gmail.com>

On 19/04/16 16:22, Mathieu Poirier wrote:
> On 19 April 2016 at 06:30, Suzuki K Poulose <Suzuki.Poulose@arm.com> wrote:
>> On 12/04/16 18:54, Mathieu Poirier wrote:
>>>
>>> Dealing with HW related matters in tmc_read_prepare/unprepare
>>> becomes convoluted when many cases need to be handled distinctively.
>>>
>>> As such moving processing related to HW setup to individual driver
>>> files and keep the core driver generic.
>>>
>>> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
>>> ---
>>>    drivers/hwtracing/coresight/coresight-tmc-etf.c | 62
>>> ++++++++++++++++++++++++-
>>>    drivers/hwtracing/coresight/coresight-tmc-etr.c | 42 ++++++++++++++++-
>>>    drivers/hwtracing/coresight/coresight-tmc.c     | 55
>>> +++++-----------------
>>>    drivers/hwtracing/coresight/coresight-tmc.h     |  8 ++--
>>>    4 files changed, 117 insertions(+), 50 deletions(-)
>>>
>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c
>>> b/drivers/hwtracing/coresight/coresight-tmc-etr.c
>>> index 910d6f3b7d26..495540e9064d 100644
>>> --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
>>> +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
>>> @@ -70,7 +70,7 @@ static void tmc_etr_dump_hw(struct tmc_drvdata *drvdata)
>>>                  drvdata->buf = drvdata->vaddr;
>>>    }
>>>
>>> -void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
>>> +static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
>>>    {
>>>          CS_UNLOCK(drvdata->base);
>>>
>>> @@ -126,3 +126,43 @@ static const struct coresight_ops_sink
>>> tmc_etr_sink_ops = {
>>>    const struct coresight_ops tmc_etr_cs_ops = {
>>>          .sink_ops       = &tmc_etr_sink_ops,
>>>    };
>>> +
>>> +int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
>>> +{
>>> +       unsigned long flags;
>>> +
>>> +       /* config types are set a boot time and never change */
>>> +       if (drvdata->config_type != TMC_CONFIG_TYPE_ETR)
>>> +               return -EINVAL;
>>
>>
>> ...
>>
>>> +
>>> +int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)
>>> +{
>>> +       unsigned long flags;
>>> +
>>> +       /* config types are set a boot time and never change */
>>> +       if (drvdata->config_type != TMC_CONFIG_TYPE_ETR)
>>> +               return -EINVAL;
>>> +
>>
>>
>> For both cases above should we WARN_ON_ONCE() if we encounter such a case ?
>
> WARN_ON_ONCE() would also be valid, albeit very blunt.  Those
> functions are user space triggered and returning -EINVAL will stop
> everything - the end result is the same.  I suppose that on such
> condition fighting back with a backtrace will force people to pay
> attention or report the problem.

We do necessary checks to route the caller here, so we shouldn't really
hit the condition with the tmc_read_prepare(). So WARN_ON_ONCE() might be a
good check to make sure we don't hit it from say, perf driver or something
really went bad under the hood (corrupted ?). I am not too particular about it.

Suzuki

  reply	other threads:[~2016-04-19 15:32 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-12 17:54 [PATCH V2 00/15] coresight: tmc: make driver usable by Perf Mathieu Poirier
2016-04-12 17:54 ` [PATCH V2 01/15] coresight: tmc: modifying naming convention Mathieu Poirier
2016-04-14 17:01   ` Suzuki K Poulose
2016-04-12 17:54 ` [PATCH V2 02/15] coresight: tmc: waiting for TMCReady bit before programming Mathieu Poirier
2016-04-14 17:05   ` Suzuki K Poulose
2016-04-12 17:54 ` [PATCH V2 03/15] coresight: tmc: re-implementing tmc_read_prepare/unprepare() functions Mathieu Poirier
2016-04-14 17:11   ` Suzuki K Poulose
2016-04-15 15:40     ` Mathieu Poirier
2016-04-15 17:41       ` Suzuki K Poulose
2016-04-12 17:54 ` [PATCH V2 04/15] coresight: tmc: introducing new header file Mathieu Poirier
2016-04-14 17:33   ` Suzuki K Poulose
2016-04-15 16:03     ` Mathieu Poirier
2016-04-15 16:08       ` Suzuki K Poulose
2016-04-15 16:15         ` Mathieu Poirier
2016-04-15 16:18           ` Suzuki K Poulose
2016-04-12 17:54 ` [PATCH V2 05/15] coresight: tmc: splitting driver in ETB/ETF and ETR components Mathieu Poirier
2016-04-19 12:20   ` Suzuki K Poulose
2016-04-19 15:14     ` Mathieu Poirier
2016-04-12 17:54 ` [PATCH V2 06/15] coresight: tmc: making prepare/unprepare functions generic Mathieu Poirier
2016-04-19 12:30   ` Suzuki K Poulose
2016-04-19 15:22     ` Mathieu Poirier
2016-04-19 15:32       ` Suzuki K Poulose [this message]
2016-04-12 17:54 ` [PATCH V2 07/15] coresight: tmc: allocating memory when needed Mathieu Poirier
2016-04-19 12:55   ` Suzuki K Poulose
2016-04-19 13:14     ` Suzuki K Poulose
2016-04-19 15:39     ` Mathieu Poirier
2016-04-12 17:54 ` [PATCH V2 08/15] coresight: tmc: getting the right read_count on tmc_open() Mathieu Poirier
2016-04-19 13:07   ` Suzuki K Poulose
2016-04-12 17:54 ` [PATCH V2 09/15] coresight: tmc: adding mode of operation for link/sinks Mathieu Poirier
2016-04-19 13:19   ` Suzuki K Poulose
2016-04-19 15:45     ` Mathieu Poirier
2016-04-19 15:49       ` Suzuki K Poulose
2016-04-12 17:54 ` [PATCH V2 10/15] coresight: tmc: dump system memory content only when needed Mathieu Poirier
2016-04-12 17:54 ` [PATCH V2 11/15] coresight: tmc: make sysFS and Perf mode mutually exclusive Mathieu Poirier
2016-04-19 13:42   ` Suzuki K Poulose
2016-04-19 16:16     ` Mathieu Poirier
2016-04-12 17:54 ` [PATCH V2 12/15] coresight: tmc: keep track of memory width Mathieu Poirier
2016-04-14 11:19   ` Suzuki K Poulose
2016-04-15 16:10     ` Mathieu Poirier
2016-04-12 17:54 ` [PATCH V2 13/15] coresight: tmc: implementing TMC-ETF AUX space API Mathieu Poirier
2016-04-19 16:16   ` Suzuki K Poulose
2016-04-19 16:45     ` Mathieu Poirier
2016-04-19 16:50       ` Suzuki K Poulose
2016-04-12 17:54 ` [PATCH V2 14/15] coresight: tmc: implementing TMC-ETR " Mathieu Poirier
2016-04-21 16:10   ` Suzuki K Poulose
2016-04-21 22:00     ` Mathieu Poirier
2016-04-12 17:54 ` [PATCH V2 15/15] coresight: configuring ETF in FIFO mode when acting as link Mathieu Poirier
2016-04-21 12:53   ` Suzuki K Poulose

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=57164F96.7000909@arm.com \
    --to=suzuki.poulose@arm.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).