bbu: move barebox_update eMMC boot handling into common code

Like with the i.MX, the STM32MP1 BootROM also consults the
EXT_CSD_PARTITION_CONFIG register to find out what to boot.

The barebox_update code used for atomic update on i.MX is thus
useful to the STM32MP as well, so move the boot switching part
to a generic location.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20220602090133.3190450-2-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 55 insertions, 0 deletions

diff --git a/common/bbu.c b/common/bbu.c
index cd7bdc40b7..6a47b21a55 100644
--- a/common/bbu.c
+++ b/common/bbu.c
@@ -19,6 +19,7 @@
 #include <malloc.h>
 #include <linux/stat.h>
 #include <image-metadata.h>
+#include <environment.h>
 #include <file-list.h>
 
 static LIST_HEAD(bbu_image_handlers);
@@ -304,6 +305,60 @@ struct bbu_std {
 	enum filetype filetype;
 };
 
+int bbu_mmcboot_handler(struct bbu_handler *handler, struct bbu_data *data,
+			int (*chained_handler)(struct bbu_handler *, struct bbu_data *))
+{
+	struct bbu_data _data = *data;
+	int ret;
+	char *bootpartvar;
+	const char *bootpart;
+	char *devicefile;
+	const char *devname = devpath_to_name(data->devicefile);
+
+	ret = device_detect_by_name(devname);
+	if (ret) {
+		pr_err("Couldn't detect device '%s'\n", devname);
+		return ret;
+	}
+
+	ret = asprintf(&bootpartvar, "%s.boot", devname);
+	if (ret < 0)
+		return ret;
+
+	bootpart = getenv(bootpartvar);
+	if (!bootpart) {
+		ret = -ENOENT;
+		goto free_bootpartvar;
+	}
+
+	if (!strcmp(bootpart, "boot0")) {
+		bootpart = "boot1";
+	} else {
+		bootpart = "boot0";
+	}
+
+	ret = asprintf(&devicefile, "/dev/%s.%s", devname, bootpart);
+	if (ret < 0)
+		goto free_bootpartvar;
+
+	_data.devicefile = devicefile;
+
+	ret = chained_handler(handler, &_data);
+	if (ret < 0)
+		goto free_devicefile;
+
+	/* on success switch boot source */
+	ret = setenv(bootpartvar, bootpart);
+
+free_devicefile:
+	free(devicefile);
+
+free_bootpartvar:
+	free(bootpartvar);
+
+	return ret;
+}
+
 static int bbu_std_file_handler(struct bbu_handler *handler,
 					struct bbu_data *data)
 {