2016-11-06 3:48 GMT+01:00 Stephen Warren <swar...@wwwdotorg.org>: > On 11/02/2016 12:06 PM, Cédric Schieli wrote: > >> At U-Boot entry point, the r2 register holds the address of the >> firmware provided boot param. Let's save it for further processing. >> > > diff --git a/board/raspberrypi/rpi/lowlevel_init.S >> b/board/raspberrypi/rpi/lowlevel_init.S >> > > +.global fw_boot_param >> +fw_boot_param: >> + .word 0x00000000 >> > > fw_dtb_pointer might be a better name; there are multiple different > registers set up by the FW in some cases; best to be explicit about what > kind of parameter is being saved. >
I did not want to use a DT oriented naming because of the possibility to pass a ATAG instead. But I can change it if you prefer. > See the note later about the size/alignment requirements for this value. > > +/* >> + * Routine: save_boot_params (called after reset from start.S) >> + * Description: save ATAG/FDT address provided by the firmware at boot >> time >> + */ >> + >> +.global save_boot_params >> +save_boot_params: >> + >> + /* The firmware provided ATAG/FDT address can be found in r2 */ >> + str r2, fw_boot_param >> > > For the 64-bit RPi builds, you need to save x0 not r2. The assembly above > doesn't compile since r2 isn't a valid register (it's named x2 on 64-bit), > plus the DTB pointer is actually in x0 not x2. > Noted. I'll address all the 64-bit issues in the next round. > > + /* Returns */ >> + b save_boot_params_ret >> > > With these patches applied, the build of rpi_defconfig fails since the > ARM1176 CPU startup file doesn't define that symbol. > > diff --git a/include/configs/rpi.h b/include/configs/rpi.h >> > > +#ifndef __ASSEMBLY__ >> +/* Firmware provided boot param */ >> +extern const void *fw_boot_param; >> +#endif >> > This issue will go away with the next round as the extern declaration will be moved to the rpi.c file, or simply removed if the save_boot_params code is converted to C. Regards, Cédric _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
