sunxi: FEL - Add the ability to recognize and auto-import uEnv-style data

The patch converts one of the "reserved" fields in the sunxi SPL
header to a fel_uEnv_length entry. When booting over USB ("FEL
mode"), this enables the sunxi-fel utility to pass the string
length of uEnv.txt compatible data; at the same time requesting
that this data be imported into the U-Boot environment.

If parse_spl_header() in the sunxi board.c encounters a non-zero
value in this header field, it will therefore call himport_r() to
merge the string (lines) passed via FEL into the default settings.
Environment vars can be changed this way even before U-Boot will
attempt to autoboot - specifically, this also allows overriding
"bootcmd".

With fel_script_addr set and a zero fel_uEnv_length, U-Boot is
safe to assume that data in .scr format (a mkimage-type script)
was passed at fel_script_addr, and will handle it using the
existing mechanism ("bootcmd_fel").

Signed-off-by: Bernhard Nortmann <bernhard.nortmann@web.de>
Acked-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/arm/include/asm/arch-sunxi/spl.h b/arch/arm/include/asm/arch-sunxi/spl.h
index ec73379735..5d7ab559ef 100644
--- a/arch/arm/include/asm/arch-sunxi/spl.h
+++ b/arch/arm/include/asm/arch-sunxi/spl.h
@@ -51,7 +51,14 @@ struct boot_file_head {
 		uint8_t spl_signature[4];
 	};
 	uint32_t fel_script_address;
-	uint32_t reserved1[3];
+	/*
+	 * If the fel_uEnv_length member below is set to a non-zero value,
+	 * it specifies the size (byte count) of data at fel_script_address.
+	 * At the same time this indicates that the data is in uEnv.txt
+	 * compatible format, ready to be imported via "env import -t".
+	 */
+	uint32_t fel_uEnv_length;
+	uint32_t reserved1[2];
 	uint32_t boot_media;		/* written here by the boot ROM */
 	uint32_t reserved2[5];		/* padding, align to 64 bytes */
 };