I am trying to bring-up eCSPI flash boot on i.MX8M Mini EVK. The flash chip is connected to ECSPI2 pins on the base board external connector.
I am using the same image that boots from SD card. Instead of SD card offset 33K, I write to SPI flash offset 1K (0x400). The image is built from mainline U-Boot v2021.07-rc3.
The serial console shows nothing when booting from SPI. But I was able to light the SOM LED using this code:
void *gpio_regs = (void *)0x30220000;
writel(0x30004, gpio_regs);
writel(0x10000, gpio_regs + 4);
Changes in the clock_init() affect the LED light is seemingly random ways. It looks like misconfiguration of clock and/or power gate makes the code hang.
Is there any clear description of clock and power configuration differences between ECSPI boot and SD card boot? The information in the Reference Manual section 6.1.4 (Device initialization) is far from clear.
Thanks,
Baruch Siach
