Timur Tabi wrote:
Wolfgang Grandegger wrote:
I think fdt_checkboard() (or boardcheck) should be run from inside the fdt_open_into() command. This takes advantage of the existing mechanism of fdt_open_into() to return an error. It also allows for a device tree to be opened after U-Boot has booted.
But it's too late for initial initialization (before RAM is available).
Just make it so that fdt_open_into() is called early:
checkboard, INIT_FUNC_WATCHDOG_INIT#if defined(CFG_FDT_ADDR_FLASH) init_fdt, #endif #if defined(CONFIG_MISC_INIT_F) misc_init_f, #endif INIT_FUNC_WATCHDOG_RESET #if defined(CONFIG_HARD_I2C) || defined(CONFIG_SOFT_I2C) init_func_i2c, #endif
and init_fdt() calls fdt_open_into().
RAM is _not_ available at that stage.
Using the FDT directly from ROM is not recommended because access might be slow, but we likely need it for early initialization.
I don't access speed is important for the reading the FDT, especially flash vs. RAM. It's not that much slower.
Depends, you might be right for FLASH on a 32-bit bus. On slow ROM devices and slow processors, it matters.
Wolfgang.