curious about recommended coding style related to modifying and verifying FDTs ... i'm perusing common/image-fdt.c and can see the order of (possible) operations here in the function image_setup_libfdt():
* arch_fixup_fdt() * ft_board_setup() * ft_system_setup() * fdt_fixup_ethernet() ... etc etc ... * ft_verify_fdt() where an earlier comment explains that last routine: /* * Verify the device tree. * * This function is called after all device tree fix-ups have been enacted, * so that the final device tree can be verified. The definition of "verified" * is up to the specific implementation. However, it generally means that the * addresses of some of the devices in the device tree are compared with the * actual addresses at which U-Boot has placed them. * * Returns 1 on success, 0 on failure. If 0 is returned, U-Boot will halt the * boot process. */ __weak int ft_verify_fdt(void *fdt) { return 1; } which seems reasonable ... after you've mangled your FDT in every way you need, optionally supply a routine to make sure it looks sane. however, for the freescale board mpc8641hpcn.c, here's part of the ft_board_setup() routine (actually, this is pretty much all that function does): if (tmp) { u64 addr; if (addrcells == 1) addr = *(u32 *)tmp; else addr = *tmp; if (addr != CONFIG_SYS_CCSRBAR_PHYS) printf("WARNING: The CCSRBAR address in your .dts " "does not match the address of the CCSR " "in u-boot. This means your .dts might " "be old.\n"); } so the board setup routine is doing some quick sanity checking, which is perfectly fine, but seems to be exactly the sort of thing ft_verify_fdt() was designed for. obviously, one can add sanity checking to any of those routines depending on how early you want to notice stuff -- is there somewhere a style guide that gives recommendations? just looking for "best practices," thanks. i'm sure there will be more FDT-related questions coming ... thank you for your patience. rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ======================================================================== _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot