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
--- A corresponding proof-of-concept version of sunxi-fel is available from my https://github.com/n1tehawk/sunxi-tools/tree/20160608_uEnv-magic branch. I've picked up the suggestion to use a "#=uEnv" magic string to request that a file be treated as uEnv.txt-style data.
For example, use your text editor to save a my.env file with
#=uEnv myvar=world bootcmd=echo "Hello $myvar."
and then test it with ./sunxi-fel uboot u-boot-sunxi-with-spl.bin write 0x43100000 my.env
You should see U-Boot's autoboot print the corresponding message and drop you to the prompt, proving that you have successfully overwritten the "bootcmd".
Changes in v3: - Dropped a surplus "return;" at the end of parse_spl_header() - Have "FEL" in the subject line to clarify the scope - Added "Acked-by" line
Changes in v2: - Patch renamed to something more suitable (was "sunxi: Add the ability to pass (script) filesize in the SPL header") - The data field is now named fel_uEnv_length, and comes with a corresponding description in spl.h - Instead of simply passing file size, fel_uEnv_length is now associated with uEnv.txt format. The patch modifies U-Boot's sunxi parse_spl_header() to auto-import such data.
arch/arm/include/asm/arch-sunxi/spl.h | 9 ++++++++- board/sunxi/board.c | 29 +++++++++++++++++++++-------- 2 files changed, 29 insertions(+), 9 deletions(-)
diff --git a/arch/arm/include/asm/arch-sunxi/spl.h b/arch/arm/include/asm/arch-sunxi/spl.h index a0f33b0..a966a88 100644 --- a/arch/arm/include/asm/arch-sunxi/spl.h +++ b/arch/arm/include/asm/arch-sunxi/spl.h @@ -49,7 +49,14 @@ 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 */ }; diff --git a/board/sunxi/board.c b/board/sunxi/board.c index d09cf6d..b5a50f4 100644 --- a/board/sunxi/board.c +++ b/board/sunxi/board.c @@ -573,6 +573,7 @@ void get_board_serial(struct tag_serialnr *serialnr)
#if !defined(CONFIG_SPL_BUILD) #include <asm/arch/spl.h> +#include <environment.h>
/* * Check the SPL header for the "sunxi" variant. If found: parse values @@ -582,17 +583,29 @@ void get_board_serial(struct tag_serialnr *serialnr) static void parse_spl_header(const uint32_t spl_addr) { struct boot_file_head *spl = (void *)(ulong)spl_addr; - if (memcmp(spl->spl_signature, SPL_SIGNATURE, 3) == 0) { - uint8_t spl_header_version = spl->spl_signature[3]; - if (spl_header_version == SPL_HEADER_VERSION) { - if (spl->fel_script_address) - setenv_hex("fel_scriptaddr", - spl->fel_script_address); - return; - } + if (memcmp(spl->spl_signature, SPL_SIGNATURE, 3) != 0) + return; /* signature mismatch, no usable header */ + + uint8_t spl_header_version = spl->spl_signature[3]; + if (spl_header_version != SPL_HEADER_VERSION) { printf("sunxi SPL version mismatch: expected %u, got %u\n", SPL_HEADER_VERSION, spl_header_version); + return; + } + if (!spl->fel_script_address) + return; + + if (spl->fel_uEnv_length != 0) { + /* + * data is expected in uEnv.txt compatible format, so "env + * import -t" the string(s) at fel_script_address right away. + */ + himport_r(&env_htab, (char *)spl->fel_script_address, + spl->fel_uEnv_length, '\n', H_NOCLEAR, 0, 0, NULL); + return; } + /* otherwise assume .scr format (mkimage-type script) */ + setenv_hex("fel_scriptaddr", spl->fel_script_address); } #endif