Hi Eric,
On 07/12/2015 15:08, Eric Nelson wrote:
I agree with you, in fact it does not work - but I do not see a way to inform the ROM that next time it should run with USB as boot device. From the fusemap, I tried to set BOOT_CFG4 as 0x40 ("Reserved for serial ROM"), and fixing BOOT_CFG1 to 0x30, but it was only a try. In fact, we need to change BMODE from internal to serial, and I do not see a way in the "official" documentation.
It doesn't help that all of this is undocumented :), but reverse- engineering the bmode command
:-)
The "bmode usb" command sets gpr9 to 1, which isn't used for anything else, so something like this will work:
diff --git a/arch/arm/imx-common/spl.c b/arch/arm/imx-common/spl.c index 28217d2..54f22e6 100644 --- a/arch/arm/imx-common/spl.c +++ b/arch/arm/imx-common/spl.c @@ -26,8 +26,10 @@ u32 spl_boot_device(void) * Check for BMODE if serial downloader is enabled * BOOT_MODE - see IMX6DQRM Table 8-1 */
if ((bmode >> 24) == 0x01) /* Serial Downloader */
if (((bmode >> 24) == 0x01) /* Serial Downloader */|| (gpr10_boot && (1 == reg))) return BOOT_DEVICE_UART;AFAIK, there isn't any other way to get a value of 1 into GPR9, so the test is safe.
This is a nice trick - I cannot see as well any combination for obtaining a 0x01 in GPR9.
Secondarily, since the low four bits are discarded in the switch(), this prevents an almost-always-wrong interpretation of 1 as OneNAND/NOR (I think there are very few if any i.MX6 boards using OneNAND or NOR for boot).
Agree.
I add your proposal in V2, thanks !
Best regards, Stefano