Messages in this thread | | | Date | Fri, 27 Apr 2018 11:39:43 -0600 | From | Lina Iyer <> | Subject | Re: [PATCH v6 05/10] drivers: qcom: rpmh-rsc: write sleep/wake requests to TCS |
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On Wed, Apr 25 2018 at 15:41 -0600, Matthias Kaehlcke wrote: >On Thu, Apr 19, 2018 at 04:16:30PM -0600, Lina Iyer wrote: >> Sleep and wake requests are sent when the application processor >> subsystem of the SoC is entering deep sleep states like in suspend. >> These requests help lower the system power requirements when the >> resources are not in use. >> >> Sleep and wake requests are written to the TCS slots but are not >> triggered at the time of writing. The TCS are triggered by the firmware >> after the last of the CPUs has executed its WFI. Since these requests >> may come in different batches of requests, it is the job of this >> controller driver to find and arrange the requests into the available >> TCSes. >> >> Signed-off-by: Lina Iyer <ilina@codeaurora.org> >> Reviewed-by: Evan Green <evgreen@chromium.org> >> --- >> drivers/soc/qcom/rpmh-internal.h | 8 +++ >> drivers/soc/qcom/rpmh-rsc.c | 120 +++++++++++++++++++++++++++++++ >> 2 files changed, 128 insertions(+) >> >> diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h >> index d9a21726e568..6e19fe458c31 100644 >> --- a/drivers/soc/qcom/rpmh-internal.h >> +++ b/drivers/soc/qcom/rpmh-internal.h > ><snip> > >> +static int find_match(const struct tcs_group *tcs, const struct tcs_cmd *cmd, >> + int len) >> +{ >> + int i, j; >> + >> + /* Check for already cached commands */ >> + for_each_set_bit(i, tcs->slots, MAX_TCS_SLOTS) { >> + for (j = 0; j < len; j++) { >> + if (tcs->cmd_cache[i] != cmd[0].addr) { > >Shouldn't the condition be 'tcs->cmd_cache[i + j] != cmd[j].addr'? > Here, we are trying to find the first address from the request and its position 'i' in the cmd_cache.
>Otherwise the code below the following if branch will never be >executed. Either the 'tcs->cmd_cache[i] != cmd[0].addr' branch isn't >entered because the addresses match, or the addresses don't match >and the inner loop is aborted after the first iteration. > >> + if (j == 0) >> + break; >> + WARN(tcs->cmd_cache[i + j] != cmd[j].addr, >> + "Message does not match previous sequence.\n"); We now check for the sequence using the iterator 'j' only after we have found 'i' (the beginning of our request).
I hope that helps clear the concern.
-- Lina
>> + return -EINVAL; >> + } else if (j == len - 1) { >> + return i; >> + } >> + } >> + } >> + >> + return -ENODATA; >> +}
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