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Date: Tue, 3 Mar 2020 11:18:08 +0530
From: Maulik Shah <mkshah@...eaurora.org>
To: Evan Green <evgreen@...omium.org>
Cc: Stephen Boyd <swboyd@...omium.org>,
Matthias Kaehlcke <mka@...omium.org>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
LKML <linux-kernel@...r.kernel.org>,
linux-arm-msm <linux-arm-msm@...r.kernel.org>,
Andy Gross <agross@...nel.org>,
Doug Anderson <dianders@...omium.org>,
Rajendra Nayak <rnayak@...eaurora.org>,
Lina Iyer <ilina@...eaurora.org>, lsrao@...eaurora.org
Subject: Re: [PATCH v9 3/3] soc: qcom: rpmh: Invoke rpmh_flush() for dirty
caches
On 2/29/2020 3:18 AM, Evan Green wrote:
> Hi Maulik,
> Thanks for spinning this so promptly.
>
> On Fri, Feb 28, 2020 at 3:38 AM Maulik Shah <mkshah@...eaurora.org> wrote:
>> Add changes to invoke rpmh flush() from within cache_lock when the data
>> in cache is dirty.
>>
>> This is done only if OSI is not supported in PSCI. If OSI is supported
>> rpmh_flush can get invoked when the last cpu going to power collapse
>> deepest low power mode.
>>
>> Also remove "depends on COMPILE_TEST" for Kconfig option QCOM_RPMH so the
>> driver is only compiled for arm64 which supports psci_has_osi_support()
>> API.
>>
>> Signed-off-by: Maulik Shah <mkshah@...eaurora.org>
>> Reviewed-by: Srinivas Rao L <lsrao@...eaurora.org>
>> ---
>> drivers/soc/qcom/Kconfig | 2 +-
>> drivers/soc/qcom/rpmh.c | 33 ++++++++++++++++++++++-----------
>> 2 files changed, 23 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
>> index d0a73e7..2e581bc 100644
>> --- a/drivers/soc/qcom/Kconfig
>> +++ b/drivers/soc/qcom/Kconfig
>> @@ -105,7 +105,7 @@ config QCOM_RMTFS_MEM
>>
>> config QCOM_RPMH
>> bool "Qualcomm RPM-Hardened (RPMH) Communication"
>> - depends on ARCH_QCOM && ARM64 || COMPILE_TEST
>> + depends on ARCH_QCOM && ARM64
>> help
>> Support for communication with the hardened-RPM blocks in
>> Qualcomm Technologies Inc (QTI) SoCs. RPMH communication uses an
>> diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
>> index f28afe4..6a5a60c 100644
>> --- a/drivers/soc/qcom/rpmh.c
>> +++ b/drivers/soc/qcom/rpmh.c
>> @@ -12,6 +12,7 @@
>> #include <linux/module.h>
>> #include <linux/of.h>
>> #include <linux/platform_device.h>
>> +#include <linux/psci.h>
>> #include <linux/slab.h>
>> #include <linux/spinlock.h>
>> #include <linux/types.h>
>> @@ -158,6 +159,13 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
>> }
>>
>> unlock:
>> + if (ctrlr->dirty && !psci_has_osi_support()) {
>> + if (rpmh_flush(ctrlr)) {
>> + spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>> + return ERR_PTR(-EINVAL);
>> + }
>> + }
>> +
>> spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>>
>> return req;
>> @@ -285,26 +293,35 @@ int rpmh_write(const struct device *dev, enum rpmh_state state,
>> }
>> EXPORT_SYMBOL(rpmh_write);
>>
>> -static void cache_batch(struct rpmh_ctrlr *ctrlr, struct batch_cache_req *req)
>> +static int cache_batch(struct rpmh_ctrlr *ctrlr, struct batch_cache_req *req)
>> {
>> unsigned long flags;
>>
>> spin_lock_irqsave(&ctrlr->cache_lock, flags);
>> +
>> list_add_tail(&req->list, &ctrlr->batch_cache);
>> ctrlr->dirty = true;
>> +
>> + if (!psci_has_osi_support()) {
>> + if (rpmh_flush(ctrlr)) {
>> + spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>> + return -EINVAL;
>> + }
>> + }
>> +
>> spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>> +
>> + return 0;
>> }
>>
>> static int flush_batch(struct rpmh_ctrlr *ctrlr)
>> {
>> struct batch_cache_req *req;
>> const struct rpmh_request *rpm_msg;
>> - unsigned long flags;
>> int ret = 0;
>> int i;
>>
>> /* Send Sleep/Wake requests to the controller, expect no response */
>> - spin_lock_irqsave(&ctrlr->cache_lock, flags);
>> list_for_each_entry(req, &ctrlr->batch_cache, list) {
>> for (i = 0; i < req->count; i++) {
>> rpm_msg = req->rpm_msgs + i;
>> @@ -314,7 +331,6 @@ static int flush_batch(struct rpmh_ctrlr *ctrlr)
>> break;
>> }
>> }
>> - spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>>
>> return ret;
>> }
>> @@ -386,10 +402,8 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state,
>> cmd += n[i];
>> }
>>
>> - if (state != RPMH_ACTIVE_ONLY_STATE) {
>> - cache_batch(ctrlr, req);
>> - return 0;
>> - }
>> + if (state != RPMH_ACTIVE_ONLY_STATE)
>> + return cache_batch(ctrlr, req);
>>
>> for (i = 0; i < count; i++) {
>> struct completion *compl = &compls[i];
>> @@ -455,9 +469,6 @@ static int send_single(struct rpmh_ctrlr *ctrlr, enum rpmh_state state,
>> * Return: -EBUSY if the controller is busy, probably waiting on a response
>> * to a RPMH request sent earlier.
>> *
>> - * This function is always called from the sleep code from the last CPU
>> - * that is powering down the entire system. Since no other RPMH API would be
>> - * executing at this time, it is safe to run lockless.
> Oh nice, I didn't even see that comment. We should probably replace
> that with a comment indicating that we assume ctrlr->cache_lock is
> already held.
>
> Please also remove this comment in rpmh_flush():
> /*
> * Nobody else should be calling this function other than system PM,
> * hence we can run without locks.
> */
> list_for_each_entry(p, &ctrlr->cache, list) {
>
> -Evan
Done, will remove in next revision.
>
>> */
>> int rpmh_flush(struct rpmh_ctrlr *ctrlr)
>> {
>> --
>> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
>> of Code Aurora Forum, hosted by The Linux Foundation
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
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