stm32mp1: add an IO to read MMC devices

Whereas the GPT table is read with io_block, the binaries to be loaded
(e.g. BL33) cannot use it, as it is not suitable to read them block by
block, or the boot time would be very bad.
Signed-off-by: Yann Gautier <yann.gautier@st.com>

drivers/st/io/io_mmc.c

+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <debug.h>
+#include <errno.h>
+#include <io_driver.h>
+#include <io_mmc.h>
+#include <io_storage.h>
+#include <mmc.h>
+#include <stm32_sdmmc2.h>
+#include <string.h>
+
+/* SDMMC device functions */
+static int mmc_dev_open(const uintptr_t init_params, io_dev_info_t **dev_info);
+static int mmc_block_open(io_dev_info_t *dev_info, const uintptr_t spec,
+			  io_entity_t *entity);
+static int mmc_dev_init(io_dev_info_t *dev_info, const uintptr_t init_params);
+static int mmc_block_seek(io_entity_t *entity, int mode, ssize_t offset);
+static int mmc_block_read(io_entity_t *entity, uintptr_t buffer, size_t length,
+			  size_t *length_read);
+static int mmc_block_close(io_entity_t *entity);
+static int mmc_dev_close(io_dev_info_t *dev_info);
+static io_type_t device_type_mmc(void);
+
+static ssize_t seek_offset;
+
+static const io_dev_connector_t mmc_dev_connector = {
+	.dev_open = mmc_dev_open
+};
+
+static const io_dev_funcs_t mmc_dev_funcs = {
+	.type = device_type_mmc,
+	.open = mmc_block_open,
+	.seek = mmc_block_seek,
+	.size = NULL,
+	.read = mmc_block_read,
+	.write = NULL,
+	.close = mmc_block_close,
+	.dev_init = mmc_dev_init,
+	.dev_close = mmc_dev_close,
+};
+
+static const io_dev_info_t mmc_dev_info = {
+	.funcs = &mmc_dev_funcs,
+	.info = 0,
+};
+
+/* Identify the device type as mmc device */
+static io_type_t device_type_mmc(void)
+{
+	return IO_TYPE_MMC;
+}
+
+/* Open a connection to the mmc device */
+static int mmc_dev_open(const uintptr_t init_params, io_dev_info_t **dev_info)
+{
+	assert(dev_info != NULL);
+	*dev_info = (io_dev_info_t *)&mmc_dev_info;
+
+	return 0;
+}
+
+static int mmc_dev_init(io_dev_info_t *dev_info, const uintptr_t init_params)
+{
+	return 0;
+}
+
+/* Close a connection to the mmc device */
+static int mmc_dev_close(io_dev_info_t *dev_info)
+{
+	return 0;
+}
+
+/* Open a file on the mmc device */
+static int mmc_block_open(io_dev_info_t *dev_info, const  uintptr_t spec,
+			  io_entity_t *entity)
+{
+	seek_offset = 0;
+	return 0;
+}
+
+/* Seek to a particular file offset on the mmc device */
+static int mmc_block_seek(io_entity_t *entity, int mode, ssize_t offset)
+{
+	seek_offset = offset;
+	return 0;
+}
+
+/* Read data from a file on the mmc device */
+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;
+	}
+
+	return 0;
+}
+
+/* Close a file on the mmc device */
+static int mmc_block_close(io_entity_t *entity)
+{
+	return 0;
+}
+
+/* Register the mmc driver with the IO abstraction */
+int register_io_dev_mmc(const io_dev_connector_t **dev_con)
+{
+	int result;
+
+	assert(dev_con != NULL);
+
+	result = io_register_device(&mmc_dev_info);
+	if (result == 0) {
+		*dev_con = &mmc_dev_connector;
+	}
+
+	return result;
+}

include/drivers/st/io_mmc.h

+/*
+ * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef IO_MMC_H
+#define IO_MMC_H
+
+#include <io_driver.h>
+
+int register_io_dev_mmc(const io_dev_connector_t **dev_con);
+
+#endif /* IO_MMC_H */