1 files changed, 47 insertions, 50 deletions

diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
index eb0ded059d2e..f2b5b46ccd1f 100644
--- a/drivers/soc/qcom/rpmh.c
+++ b/drivers/soc/qcom/rpmh.c
@@ -9,6 +9,7 @@
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
+#include <linux/lockdep.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
@@ -119,6 +120,7 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
 {
 	struct cache_req *req;
 	unsigned long flags;
+	u32 old_sleep_val, old_wake_val;
 
 	spin_lock_irqsave(&ctrlr->cache_lock, flags);
 	req = __find_req(ctrlr, cmd->addr);
@@ -133,26 +135,27 @@ 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:
+	old_sleep_val = req->sleep_val;
+	old_wake_val = req->wake_val;
+
 	switch (state) {
 	case RPMH_ACTIVE_ONLY_STATE:
-		if (req->sleep_val != UINT_MAX)
-			req->wake_val = cmd->data;
-		break;
 	case RPMH_WAKE_ONLY_STATE:
 		req->wake_val = cmd->data;
 		break;
 	case RPMH_SLEEP_STATE:
 		req->sleep_val = cmd->data;
 		break;
-	default:
-		break;
 	}
 
-	ctrlr->dirty = true;
+	ctrlr->dirty |= (req->sleep_val != old_sleep_val ||
+			 req->wake_val != old_wake_val) &&
+			 req->sleep_val != UINT_MAX &&
+			 req->wake_val != UINT_MAX;
+
 unlock:
 	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
 
@@ -287,6 +290,7 @@ 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);
 }
 
@@ -294,12 +298,10 @@ 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;
@@ -309,23 +311,10 @@ static int flush_batch(struct rpmh_ctrlr *ctrlr)
 				break;
 		}
 	}
-	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
 
 	return ret;
 }
 
-static void invalidate_batch(struct rpmh_ctrlr *ctrlr)
-{
-	struct batch_cache_req *req, *tmp;
-	unsigned long flags;
-
-	spin_lock_irqsave(&ctrlr->cache_lock, flags);
-	list_for_each_entry_safe(req, tmp, &ctrlr->batch_cache, list)
-		kfree(req);
-	INIT_LIST_HEAD(&ctrlr->batch_cache);
-	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
-}
-
 /**
  * rpmh_write_batch: Write multiple sets of RPMH commands and wait for the
  * batch to finish.
@@ -442,36 +431,42 @@ static int send_single(struct rpmh_ctrlr *ctrlr, enum rpmh_state state,
 }
 
 /**
- * rpmh_flush: Flushes the buffered active and sleep sets to TCS
- *
- * @ctrlr: controller making request to flush cached data
+ * rpmh_flush() - Flushes the buffered sleep and wake sets to TCSes
  *
- * Return: -EBUSY if the controller is busy, probably waiting on a response
- * to a RPMH request sent earlier.
+ * @ctrlr: Controller making request to flush cached data
  *
- * 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.
+ * Return:
+ * * 0          - Success
+ * * Error code - Otherwise
  */
 int rpmh_flush(struct rpmh_ctrlr *ctrlr)
 {
 	struct cache_req *p;
-	int ret;
+	int ret = 0;
+
+	lockdep_assert_irqs_disabled();
+
+	/*
+	 * Currently rpmh_flush() is only called when we think we're running
+	 * on the last processor.  If the lock is busy it means another
+	 * processor is up and it's better to abort than spin.
+	 */
+	if (!spin_trylock(&ctrlr->cache_lock))
+		return -EBUSY;
 
 	if (!ctrlr->dirty) {
 		pr_debug("Skipping flush, TCS has latest data.\n");
-		return 0;
+		goto exit;
 	}
 
+	/* Invalidate the TCSes first to avoid stale data */
+	rpmh_rsc_invalidate(ctrlr_to_drv(ctrlr));
+
 	/* First flush the cached batch requests */
 	ret = flush_batch(ctrlr);
 	if (ret)
-		return ret;
+		goto exit;
 
-	/*
-	 * 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",
@@ -481,38 +476,40 @@ int rpmh_flush(struct rpmh_ctrlr *ctrlr)
 		ret = send_single(ctrlr, RPMH_SLEEP_STATE, p->addr,
 				  p->sleep_val);
 		if (ret)
-			return ret;
+			goto exit;
 		ret = send_single(ctrlr, RPMH_WAKE_ONLY_STATE, p->addr,
 				  p->wake_val);
 		if (ret)
-			return ret;
+			goto exit;
 	}
 
 	ctrlr->dirty = false;
 
-	return 0;
+exit:
+	spin_unlock(&ctrlr->cache_lock);
+	return ret;
 }
 
 /**
- * rpmh_invalidate: Invalidate all sleep and active sets
- * sets.
+ * rpmh_invalidate: Invalidate sleep and wake sets in batch_cache
  *
  * @dev: The device making the request
  *
- * Invalidate the sleep and active values in the TCS blocks.
+ * Invalidate the sleep and wake values in batch_cache.
  */
 int rpmh_invalidate(const struct device *dev)
 {
 	struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
-	int ret;
+	struct batch_cache_req *req, *tmp;
+	unsigned long flags;
 
-	invalidate_batch(ctrlr);
+	spin_lock_irqsave(&ctrlr->cache_lock, flags);
+	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);
 
-	do {
-		ret = rpmh_rsc_invalidate(ctrlr_to_drv(ctrlr));
-	} while (ret == -EAGAIN);
-
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(rpmh_invalidate);