linux-kernel - [PATCH v8 2/3] soc: qcom: rpmh: Update dirty flag only when data changes

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Message-Id: <1582793785-22423-3-git-send-email-mkshah@codeaurora.org>
Date:   Thu, 27 Feb 2020 14:26:24 +0530
From:   Maulik Shah <mkshah@...eaurora.org>
To:     swboyd@...omium.org, mka@...omium.org, evgreen@...omium.org,
        bjorn.andersson@...aro.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        agross@...nel.org, dianders@...omium.org, rnayak@...eaurora.org,
        ilina@...eaurora.org, lsrao@...eaurora.org,
        Maulik Shah <mkshah@...eaurora.org>
Subject: [PATCH v8 2/3] soc: qcom: rpmh: Update dirty flag only when data changes

Currently rpmh ctrlr dirty flag is set for all cases regardless of data
is really changed or not. Add changes to update dirty flag when data is
changed to newer values.

Also move dirty flag updates to happen from within cache_lock and remove
unnecessary INIT_LIST_HEAD() call and a default case from switch.

Fixes: 600513dfeef3 ("drivers: qcom: rpmh: cache sleep/wake state requests")
Signed-off-by: Maulik Shah <mkshah@...eaurora.org>
Reviewed-by: Srinivas Rao L <lsrao@...eaurora.org>
---
 drivers/soc/qcom/rpmh.c | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
index eb0ded0..3f5d9eb 100644
--- a/drivers/soc/qcom/rpmh.c
+++ b/drivers/soc/qcom/rpmh.c
@@ -133,26 +133,30 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
 
 	req->addr = cmd->addr;
 	req->sleep_val = req->wake_val = UINT_MAX;
-	INIT_LIST_HEAD(&req->list);
 	list_add_tail(&req->list, &ctrlr->cache);
 
 existing:
 	switch (state) {
 	case RPMH_ACTIVE_ONLY_STATE:
-		if (req->sleep_val != UINT_MAX)
+		if (req->sleep_val != UINT_MAX) {
 			req->wake_val = cmd->data;
+			ctrlr->dirty = true;
+		}
 		break;
 	case RPMH_WAKE_ONLY_STATE:
-		req->wake_val = cmd->data;
+		if (req->wake_val != cmd->data) {
+			req->wake_val = cmd->data;
+			ctrlr->dirty = true;
+		}
 		break;
 	case RPMH_SLEEP_STATE:
-		req->sleep_val = cmd->data;
-		break;
-	default:
+		if (req->sleep_val != cmd->data) {
+			req->sleep_val = cmd->data;
+			ctrlr->dirty = true;
+		}
 		break;
 	}
 
-	ctrlr->dirty = true;
 unlock:
 	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
 
@@ -287,6 +291,7 @@ static void cache_batch(struct rpmh_ctrlr *ctrlr, struct batch_cache_req *req)
 
 	spin_lock_irqsave(&ctrlr->cache_lock, flags);
 	list_add_tail(&req->list, &ctrlr->batch_cache);
+	ctrlr->dirty = true;
 	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
 }
 
@@ -323,6 +328,7 @@ static void invalidate_batch(struct rpmh_ctrlr *ctrlr)
 	list_for_each_entry_safe(req, tmp, &ctrlr->batch_cache, list)
 		kfree(req);
 	INIT_LIST_HEAD(&ctrlr->batch_cache);
+	ctrlr->dirty = true;
 	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
 }
 
@@ -456,13 +462,9 @@ static int send_single(struct rpmh_ctrlr *ctrlr, enum rpmh_state state,
 int rpmh_flush(struct rpmh_ctrlr *ctrlr)
 {
 	struct cache_req *p;
+	unsigned long flags;
 	int ret;
 
-	if (!ctrlr->dirty) {
-		pr_debug("Skipping flush, TCS has latest data.\n");
-		return 0;
-	}
-
 	/* First flush the cached batch requests */
 	ret = flush_batch(ctrlr);
 	if (ret)
@@ -488,7 +490,9 @@ int rpmh_flush(struct rpmh_ctrlr *ctrlr)
 			return ret;
 	}
 
+	spin_lock_irqsave(&ctrlr->cache_lock, flags);
 	ctrlr->dirty = false;
+	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
 
 	return 0;
 }
@@ -507,7 +511,6 @@ int rpmh_invalidate(const struct device *dev)
 	int ret;
 
 	invalidate_batch(ctrlr);
-	ctrlr->dirty = true;
 
 	do {
 		ret = rpmh_rsc_invalidate(ctrlr_to_drv(ctrlr));
-- 
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