bootstd: mmc: Add a bootdev driver

Add a bootdev driver for MMC. It mostly just calls the bootdev helper
function.

Add a function to obtain the block device for an MMC controller.

Fix up the comment for mmc_get_blk_desc() while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 62 insertions, 0 deletions

diff --git a/drivers/mmc/mmc_bootdev.c b/drivers/mmc/mmc_bootdev.c
new file mode 100644
index 00000000000..b4f41fb3a67
--- /dev/null
+++ b/drivers/mmc/mmc_bootdev.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Bootdevice for MMC
+ *
+ * Copyright 2021 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <bootdev.h>
+#include <dm.h>
+#include <mmc.h>
+
+static int mmc_get_bootflow(struct udevice *dev, struct bootflow_iter *iter,
+			    struct bootflow *bflow)
+{
+	struct udevice *mmc_dev = dev_get_parent(dev);
+	struct udevice *blk;
+	int ret;
+
+	ret = mmc_get_blk(mmc_dev, &blk);
+	/*
+	 * If there is no media, indicate that no more partitions should be
+	 * checked
+	 */
+	if (ret == -EOPNOTSUPP)
+		ret = -ESHUTDOWN;
+	if (ret)
+		return log_msg_ret("blk", ret);
+	assert(blk);
+	ret = bootdev_find_in_blk(dev, blk, iter, bflow);
+	if (ret)
+		return log_msg_ret("find", ret);
+
+	return 0;
+}
+
+static int mmc_bootdev_bind(struct udevice *dev)
+{
+	struct bootdev_uc_plat *ucp = dev_get_uclass_plat(dev);
+
+	ucp->prio = BOOTDEVP_0_INTERNAL_FAST;
+
+	return 0;
+}
+
+struct bootdev_ops mmc_bootdev_ops = {
+	.get_bootflow	= mmc_get_bootflow,
+};
+
+static const struct udevice_id mmc_bootdev_ids[] = {
+	{ .compatible = "u-boot,bootdev-mmc" },
+	{ }
+};
+
+U_BOOT_DRIVER(mmc_bootdev) = {
+	.name		= "mmc_bootdev",
+	.id		= UCLASS_BOOTDEV,
+	.ops		= &mmc_bootdev_ops,
+	.bind		= mmc_bootdev_bind,
+	.of_match	= mmc_bootdev_ids,
+};