Hi,
On 02-09-15 15:17, Bernhard Nortmann wrote:
This patch follows up on a discussion of ways to improve support
for the sunxi FEL ("USB boot") mechanism, especially with regard
to boot scripts, see:
https://groups.google.com/d/msg/linux-sunxi/wBEGUoLNRro/rHGq6nSYCQAJ
The idea is to convert the (currently unused) "pad" bytes in the
SPL header into an area where data can be passed to U-Boot. To
do this safely, we have to make sure that we're actually using
our "sunxi" flavor of the SPL, and not the Allwinner boot0.
The modified mksunxiboot introduces a special signature to the
SPL header in place of the "pub_head_size" field. This can be
used to reliably distinguish between compatible versions of sunxi
SPL and anything else (older variants or Allwinner's boot0).
Signed-off-by: Bernhard Nortmann <bernhard.nortm...@web.de>
---
tools/mksunxiboot.c | 27 ++++++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)
diff --git a/tools/mksunxiboot.c b/tools/mksunxiboot.c
index 3361251..58bc5c7 100644
--- a/tools/mksunxiboot.c
+++ b/tools/mksunxiboot.c
@@ -27,12 +27,31 @@ struct boot_file_head {
* by the boot ROM. To be compatible with Allwinner tools we
* would need to implement the proper fields here instead of
* padding.
+ *
+ * Actually we want the ability to recognize our "sunxi" variant
+ * of the SPL. To do so, let's place a special signature into the
+ * "pub_head_size" field. We can reasonably expect Allwinner's
+ * boot0 to always have the upper 16 bits of this set to 0 (after
+ * all the value shouldn't be larger than the limit imposed by
+ * SRAM size).
+ * If the signature is present (at 0x14), then we know it's safe
+ * to use the remaining 8 bytes (at 0x18) for our own purposes.
+ * (E.g. sunxi-tools "fel" utility can pass information there.)
+ *
+ * The overall header size still sums up to 32 bytes.
*/
- uint8_t pad[12]; /* align to 32 bytes */
+ union {
+ uint32_t pub_head_size;
+ uint8_t spl_signature[4];
+ };
+ uint32_t fel_data_address;
+ uint32_t fel_data_size;
I believe these 2 should be renamed to:
uint32_t fel_boot_script_address;
uint32_t fel_boot_script_size;
To properly reflect what they are (they are not some abstract
data, they are specifically a boot.scr image)
With that changed and Siarhei's ack for the series (I'm assuming
Sairhei will take care of the sunxi-tools side of things),
I'm ok with merging this.
Regards,
Hans
I
};
#define BOOT0_MAGIC "eGON.BT0"
#define STAMP_VALUE 0x5F0A6C39
+#define SPL_SIGNATURE "SPL" /* marks "sunxi" header */
+#define SPL_HEADER_VERSION 1
/* check sum functon from sun4i boot code */
int gen_check_sum(struct boot_file_head *head_p)
@@ -133,6 +152,12 @@ int main(int argc, char *argv[])
ALIGN(file_size + sizeof(struct boot_file_head), BLOCK_SIZE);
img.header.b_instruction = cpu_to_le32(img.header.b_instruction);
img.header.length = cpu_to_le32(img.header.length);
+
+ memcpy(img.header.spl_signature, SPL_SIGNATURE, 3); /* "sunxi" marker */
+ img.header.spl_signature[3] = SPL_HEADER_VERSION;
+ img.header.fel_data_address = 0; /* ensure fields are zeroed */
+ img.header.fel_data_size = 0;
+
gen_check_sum(&img.header);
count = write(fd_out, &img, le32_to_cpu(img.header.length));
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