mmc: st: correct retries management

The retries number should be 3.
A warning message is added in mmc_block_read(), and the code is refactored.

Change-Id: I577c7dd91c451c7580b1660042cb5fe26ee3fa12
Signed-off-by: Yann Gautier <yann.gautier@st.com>

drivers/st/io/io_mmc.c

 /*
- * Copyright (c) 2018-2019, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2020, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -97,14 +97,21 @@ static int mmc_block_seek(io_entity_t *entity, int mode,
 static int mmc_block_read(io_entity_t *entity, uintptr_t buffer,
 			  size_t length, size_t *length_read)
 {
-	*length_read = mmc_read_blocks(seek_offset / MMC_BLOCK_SIZE,
-				       buffer, length);
-
-	if (*length_read != length) {
-		return -EIO;
+	uint8_t retries;
+
+	for (retries = 0U; retries < 3U; retries++) {
+		*length_read = mmc_read_blocks(seek_offset / MMC_BLOCK_SIZE,
+					       buffer, length);
+
+		if (*length_read == length) {
+			return 0;
+		}
+		WARN("%s: length_read = %lu (!= %lu), retry %u\n", __func__,
+		     (unsigned long)*length_read, (unsigned long)length,
+		     retries + 1U);
 	}
 
-	return 0;
+	return -EIO;
 }
 
 /* Close a file on the mmc device */

drivers/st/mmc/stm32_sdmmc2.c

 /*
- * Copyright (c) 2018-2019, STMicroelectronics - All Rights Reserved
+ * Copyright (c) 2018-2020, STMicroelectronics - All Rights Reserved
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -373,15 +373,15 @@ err_exit:
 
 static int stm32_sdmmc2_send_cmd(struct mmc_cmd *cmd)
 {
-	int8_t retry;
-	int err = 0;
+	uint8_t retry;
+	int err;
 
 	assert(cmd != NULL);
 
-	for (retry = 0; retry <= 3; retry++) {
+	for (retry = 0U; retry < 3U; retry++) {
 		err = stm32_sdmmc2_send_cmd_req(cmd);
 		if (err == 0) {
-			return err;
+			return 0;
 		}
 
 		if ((cmd->cmd_idx == MMC_CMD(1)) ||
@@ -390,12 +390,12 @@ static int stm32_sdmmc2_send_cmd(struct mmc_cmd *cmd)
 		}
 
 		/* Command 8 is expected to fail for eMMC */
-		if (!(cmd->cmd_idx == MMC_CMD(8))) {
-			WARN(" CMD%d, Retry: %d, Error: %d\n",
-			     cmd->cmd_idx, retry, err);
+		if (cmd->cmd_idx != MMC_CMD(8)) {
+			WARN(" CMD%u, Retry: %u, Error: %d\n",
+			     cmd->cmd_idx, retry + 1U, err);
 		}
 
-		udelay(10);
+		udelay(10U);
 	}
 
 	return err;