feat(drivers/st): manage boot part in io_mmc

Use dedicated read function for boot partition
Signed-off-by: Vyacheslav Yurkov <uvv.mail@gmail.com>
Change-Id: If75df7691fce0797205365736fc6e4e3429efdca

drivers/st/io/io_mmc.c

 /*
- * Copyright (c) 2018-2020, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2021, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -29,6 +29,7 @@ static int mmc_dev_close(io_dev_info_t *dev_info);
 static io_type_t device_type_mmc(void);
 
 static signed long long seek_offset;
+static size_t (*_read_blocks)(int lba, uintptr_t buf, size_t size);
 
 static const io_dev_connector_t mmc_dev_connector = {
 	.dev_open = mmc_dev_open
@@ -60,9 +61,15 @@ static io_type_t device_type_mmc(void)
 /* Open a connection to the mmc device */
 static int mmc_dev_open(const uintptr_t init_params, io_dev_info_t **dev_info)
 {
+	struct io_mmc_dev_spec *device_spec =
+		(struct io_mmc_dev_spec *)init_params;
+
 	assert(dev_info != NULL);
 	*dev_info = (io_dev_info_t *)&mmc_dev_info;
 
+	_read_blocks = !device_spec->use_boot_part ?
+		mmc_read_blocks : mmc_boot_part_read_blocks;
+
 	return 0;
 }
 
@@ -100,8 +107,8 @@ static int mmc_block_read(io_entity_t *entity, uintptr_t buffer,
 	uint8_t retries;
 
 	for (retries = 0U; retries < 3U; retries++) {
-		*length_read = mmc_read_blocks(seek_offset / MMC_BLOCK_SIZE,
-					       buffer, length);
+		*length_read = _read_blocks(seek_offset / MMC_BLOCK_SIZE,
+					    buffer, length);
 
 		if (*length_read == length) {
 			return 0;

include/drivers/st/io_mmc.h

 /*
- * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2021, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -9,6 +9,10 @@
 
 #include <drivers/io/io_driver.h>
 
+struct io_mmc_dev_spec {
+	bool use_boot_part;
+};
+
 int register_io_dev_mmc(const io_dev_connector_t **dev_con);
 
 #endif /* IO_MMC_H */