Hi Stefano,
On 12.11.2012 14:02, Stefano Babic wrote:
On 12/11/2012 12:35, Andreas Bießmann wrote:
<snip>
+Function that a board must implement +------------------------------------
+void spl_board_prepare_for_linux(void) : optional
- Called from SPL before starting the kernel
+spl_start_uboot() : required
Returns "0" if SPL starts the kernel, "1" if U-Bootmust be started.In which way interact the CONFIG_SPL_OS_BOOT_KEY with the spl_start_uboot()? Is both required, can one use one or the other?
Really checking the implementation, it should be better to remove CONFIG_SPL_OS_BOOT_KEY. There is not a weak function for spl_start_uboot(), and I think it is better so. But CONFIG_SPL_OS_BOOT_KEY is used only inside spl_start_uboot() in the board's implementation. IMHO it will be better to use a local define for the GPIOs inside board files, and drop CONFIG_SPL_OS_BOOT_KEY (in another patch, I mean).
sounds good to me.
+img : "atags" or "fdt" +kernel_addr : kernel is loaded as part of the boot process, but it is not started.
This is the address where a kernel image is stored.-------------------------------------------------------------^ persistently? This is the place in mass storage, right?
No, but it could be (for NOR flash, for example). It is the address where a uImage can be found. It could be in RAM after loading it with tftp, or in a NOR flash.
In any case, the spl command does not call itself utilities to copy the kernel from mass storage - such as "nand read" or "fatload", for example.
Ok, thats what I thought. But on first read of this README it was not clear to me which address I should write there. The step by step example should have some 'nand read' in it to clarify.
+init_addr : optional for atags - the address where the parameters area is generated into RAM
how about the initrd_addr mentioned above?
What is not clear ? init_addr is the destination address, where spl puts its result. Is it not clear from the description ?
Well, the usage() for spl does not have a 'init_addr' but an 'initrd_addr'. Also your example line states:
---8<--- Usage: spl export <img=atags|fdt> [kernel_addr] [initrd_addr] [fdt_addr if <img> = fdt] - export a kernel parameter image initrd_img can be set to "-" if fdt_addr without initrd img isused --->8---
So for me it is not clear where the 'init_addr' come from. BTW: I find your detailed description way better than current usage() of spl command. Would IMHO be useful to add it there in another patch. another BTW: is there a typo in usage() for spl cmd? One line states 'initrd_addr' but some later it says 'initrd_img'.
And last: the spl puts its result at a self gained position. The position is defined at compile time or when generating the uImage but not at command line for 'spl export' (see spl_export(): gd->bd->bi_boot_params vs. images.ft_addr).
Best regards
Andreas Bießmann