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Subject[PATCH v13 4/5] soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches
Date
Add changes to invoke rpmh flush() from within cache_lock when the data in
cache is dirty.

Introduce two new APIs for this. Clients can use rpmh_start_transaction()
before any rpmh transaction once done invoke rpmh_end_transaction() which
internally invokes rpmh_flush() if the caches has become dirty.

Add support to control this with flush_dirty flag.

Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Srinivas Rao L <lsrao@codeaurora.org>
---
drivers/soc/qcom/rpmh-internal.h | 4 +++
drivers/soc/qcom/rpmh-rsc.c | 6 +++-
drivers/soc/qcom/rpmh.c | 64 ++++++++++++++++++++++++++++++++--------
include/soc/qcom/rpmh.h | 10 +++++++
4 files changed, 71 insertions(+), 13 deletions(-)

diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h
index 6eec32b..d36be3d 100644
--- a/drivers/soc/qcom/rpmh-internal.h
+++ b/drivers/soc/qcom/rpmh-internal.h
@@ -70,13 +70,17 @@ struct rpmh_request {
*
* @cache: the list of cached requests
* @cache_lock: synchronize access to the cache data
+ * @active_clients: count of rpmh transaction in progress
* @dirty: was the cache updated since flush
+ * @flush_dirty: if the dirty cache need immediate flush
* @batch_cache: Cache sleep and wake requests sent as batch
*/
struct rpmh_ctrlr {
struct list_head cache;
spinlock_t cache_lock;
+ u32 active_clients;
bool dirty;
+ bool flush_dirty;
struct list_head batch_cache;
};

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index e278fc1..b6391e1 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -61,6 +61,8 @@
#define CMD_STATUS_ISSUED BIT(8)
#define CMD_STATUS_COMPL BIT(16)

+#define FLUSH_DIRTY 1
+
static u32 read_tcs_reg(struct rsc_drv *drv, int reg, int tcs_id, int cmd_id)
{
return readl_relaxed(drv->tcs_base + reg + RSC_DRV_TCS_OFFSET * tcs_id +
@@ -670,13 +672,15 @@ static int rpmh_rsc_probe(struct platform_device *pdev)
INIT_LIST_HEAD(&drv->client.cache);
INIT_LIST_HEAD(&drv->client.batch_cache);

+ drv->client.flush_dirty = device_get_match_data(&pdev->dev);
+
dev_set_drvdata(&pdev->dev, drv);

return devm_of_platform_populate(&pdev->dev);
}

static const struct of_device_id rpmh_drv_match[] = {
- { .compatible = "qcom,rpmh-rsc", },
+ { .compatible = "qcom,rpmh-rsc", .data = (void *)FLUSH_DIRTY },
{ }
};

diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
index 5bed8f4..9d40209 100644
--- a/drivers/soc/qcom/rpmh.c
+++ b/drivers/soc/qcom/rpmh.c
@@ -297,12 +297,10 @@ 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;
@@ -312,7 +310,6 @@ static int flush_batch(struct rpmh_ctrlr *ctrlr)
break;
}
}
- spin_unlock_irqrestore(&ctrlr->cache_lock, flags);

return ret;
}
@@ -433,16 +430,63 @@ static int send_single(struct rpmh_ctrlr *ctrlr, enum rpmh_state state,
}

/**
+ * rpmh_start_transaction: Indicates start of rpmh transactions, this
+ * must be ended by invoking rpmh_end_transaction().
+ *
+ * @dev: the device making the request
+ */
+void rpmh_start_transaction(const struct device *dev)
+{
+ struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
+ unsigned long flags;
+
+ if (!ctrlr->flush_dirty)
+ return;
+
+ spin_lock_irqsave(&ctrlr->cache_lock, flags);
+ ctrlr->active_clients++;
+ spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
+}
+EXPORT_SYMBOL(rpmh_start_transaction);
+
+/**
+ * rpmh_end_transaction: Indicates end of rpmh transactions. All dirty data
+ * in cache can be flushed immediately when ctrlr->flush_dirty is set
+ *
+ * @dev: the device making the request
+ *
+ * Return: 0 on success, error number otherwise.
+ */
+int rpmh_end_transaction(const struct device *dev)
+{
+ struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
+ unsigned long flags;
+ int ret = 0;
+
+ if (!ctrlr->flush_dirty)
+ return ret;
+
+ spin_lock_irqsave(&ctrlr->cache_lock, flags);
+
+ ctrlr->active_clients--;
+ if (ctrlr->dirty && !ctrlr->active_clients)
+ ret = rpmh_flush(ctrlr);
+
+ spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL(rpmh_end_transaction);
+
+/**
* rpmh_flush: Flushes the buffered active and sleep sets to TCS
*
* @ctrlr: controller making request to flush cached data
*
- * Return: -EBUSY if the controller is busy, probably waiting on a response
- * to a RPMH request sent earlier.
+ * Return: 0 on success, error number otherwise.
*
- * 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.
+ * This function can either be called from sleep code on the last CPU
+ * (thus no spinlock needed) or with the ctrlr->cache_lock already held.
*/
int rpmh_flush(struct rpmh_ctrlr *ctrlr)
{
@@ -464,10 +508,6 @@ int rpmh_flush(struct rpmh_ctrlr *ctrlr)
if (ret)
return ret;

- /*
- * 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) {
if (!is_req_valid(p)) {
pr_debug("%s: skipping RPMH req: a:%#x s:%#x w:%#x",
diff --git a/include/soc/qcom/rpmh.h b/include/soc/qcom/rpmh.h
index f9ec353..85e1ab2 100644
--- a/include/soc/qcom/rpmh.h
+++ b/include/soc/qcom/rpmh.h
@@ -22,6 +22,10 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state,

int rpmh_invalidate(const struct device *dev);

+void rpmh_start_transaction(const struct device *dev);
+
+int rpmh_end_transaction(const struct device *dev);
+
#else

static inline int rpmh_write(const struct device *dev, enum rpmh_state state,
@@ -41,6 +45,12 @@ static inline int rpmh_write_batch(const struct device *dev,
static inline int rpmh_invalidate(const struct device *dev)
{ return -ENODEV; }

+void rpmh_start_transaction(const struct device *dev)
+{ return -ENODEV; }
+
+int rpmh_end_transaction(const struct device *dev)
+{ return -ENODEV; }
+
#endif /* CONFIG_QCOM_RPMH */

#endif /* __SOC_QCOM_RPMH_H__ */
--
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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