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.nortm...@web.de>
---
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 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 | 30 ++++++++++++++++++++++--------
2 files changed, 30 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..fc57e60 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 +583,30 @@ 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);
+ return;
}
#endif
--
2.7.3
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