1 files changed, 36 insertions, 12 deletions

diff --git a/drivers/crypto/stm32/stm32-crc32.c b/drivers/crypto/stm32/stm32-crc32.c
index 1c3e411b7acb..10304511f9b4 100644
--- a/drivers/crypto/stm32/stm32-crc32.c
+++ b/drivers/crypto/stm32/stm32-crc32.c
@@ -91,16 +91,29 @@ static int stm32_crc_setkey(struct crypto_shash *tfm, const u8 *key,
 	return 0;
 }
 
-static int stm32_crc_init(struct shash_desc *desc)
+static struct stm32_crc *stm32_crc_get_next_crc(void)
 {
-	struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
-	struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
 	struct stm32_crc *crc;
 
 	spin_lock_bh(&crc_list.lock);
 	crc = list_first_entry(&crc_list.dev_list, struct stm32_crc, list);
+	if (crc)
+		list_move_tail(&crc->list, &crc_list.dev_list);
 	spin_unlock_bh(&crc_list.lock);
 
+	return crc;
+}
+
+static int stm32_crc_init(struct shash_desc *desc)
+{
+	struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
+	struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
+	struct stm32_crc *crc;
+
+	crc = stm32_crc_get_next_crc();
+	if (!crc)
+		return -ENODEV;
+
 	pm_runtime_get_sync(crc->dev);
 
 	/* Reset, set key, poly and configure in bit reverse mode */
@@ -125,9 +138,9 @@ static int stm32_crc_update(struct shash_desc *desc, const u8 *d8,
 	struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
 	struct stm32_crc *crc;
 
-	spin_lock_bh(&crc_list.lock);
-	crc = list_first_entry(&crc_list.dev_list, struct stm32_crc, list);
-	spin_unlock_bh(&crc_list.lock);
+	crc = stm32_crc_get_next_crc();
+	if (!crc)
+		return -ENODEV;
 
 	pm_runtime_get_sync(crc->dev);
 
@@ -200,6 +213,8 @@ static int stm32_crc_digest(struct shash_desc *desc, const u8 *data,
 	return stm32_crc_init(desc) ?: stm32_crc_finup(desc, data, length, out);
 }
 
+static unsigned int refcnt;
+static DEFINE_MUTEX(refcnt_lock);
 static struct shash_alg algs[] = {
 	/* CRC-32 */
 	{
@@ -290,12 +305,18 @@ static int stm32_crc_probe(struct platform_device *pdev)
 	list_add(&crc->list, &crc_list.dev_list);
 	spin_unlock(&crc_list.lock);
 
-	ret = crypto_register_shashes(algs, ARRAY_SIZE(algs));
-	if (ret) {
-		dev_err(dev, "Failed to register\n");
-		clk_disable_unprepare(crc->clk);
-		return ret;
+	mutex_lock(&refcnt_lock);
+	if (!refcnt) {
+		ret = crypto_register_shashes(algs, ARRAY_SIZE(algs));
+		if (ret) {
+			mutex_unlock(&refcnt_lock);
+			dev_err(dev, "Failed to register\n");
+			clk_disable_unprepare(crc->clk);
+			return ret;
+		}
 	}
+	refcnt++;
+	mutex_unlock(&refcnt_lock);
 
 	dev_info(dev, "Initialized\n");
 
@@ -316,7 +337,10 @@ static int stm32_crc_remove(struct platform_device *pdev)
 	list_del(&crc->list);
 	spin_unlock(&crc_list.lock);
 
-	crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
+	mutex_lock(&refcnt_lock);
+	if (!--refcnt)
+		crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
+	mutex_unlock(&refcnt_lock);
 
 	pm_runtime_disable(crc->dev);
 	pm_runtime_put_noidle(crc->dev);