[PATCH v9 3/3] soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches

[Maulik Shah]

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@xxxxxxxxxxxxxx>
Reviewed-by: Srinivas Rao L <lsrao@xxxxxxxxxxxxxx>
---
 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.
  */
 int rpmh_flush(struct rpmh_ctrlr *ctrlr)
 {
-- 
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