On 9/3/20 2:14 PM, Dennis Gilmore wrote:
On Thu, Sep 3, 2020 at 2:15 PM Stephen Warren swarren@wwwdotorg.org wrote:
On 9/3/20 10:40 AM, Dennis Gilmore wrote:
When testing builds provided in https://github.com/openwrt/openwrt/pull/3360 I discovered that fdtfile was not set and as a result the firmware was not functional. So I am documenting what is needed.
Signed-off-by: Dennis Gilmore dennis@ausil.us
Cc: Atish Patra atish.patra@wdc.com Cc: Lukas Auer lukas.auer@aisec.fraunhofer.de Cc: Tom Rini trini@konsulko.com Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: Vagrant Cascadian vagrant@debian.org Cc: Stephen Warren swarren@nvidia.com Cc: Karsten Merker merker@debian.org
doc/README.distro | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/doc/README.distro b/doc/README.distro index 5076bebd18..3eb70aeb14 100644 --- a/doc/README.distro +++ b/doc/README.distro @@ -224,6 +224,14 @@ fdt_addr_r:
A size of 1MB for the FDT/DTB seems reasonable.
+fdtfile:
- Mandatory. the name of the DTB file for the specific board for instance
- the espressobin v5 board the value is "marvell/armada-3720-espressobin.dtb"
- while on a clearfog pro it is "armada-388-clearfog-pro.dtb" in the case of
- a board providing its firmware based DTB this value can be used to override
- the DTB with a different DTB.
IIRC this variable isn't mandatory; if the DT filename follows expected ${soc}-${board}.dtb naming, then U-Boot has a default value that will work without the user or U-Boot author having to manually set this variable.
So it's certainly mandatory that U-Boot know this value at runtime, but perhaps the text should be expanded to indicate that sometimes U-Boot can provide the value itself, but sometimes the variable needs to be set?
in include/config_distro_bootcmd.h we have the following /*
- On 32bit ARM systems there is a reasonable number of systems that follow
- the $soc-$board$boardver.dtb name scheme for their device trees. Use that
- scheme if we don't have an explicit fdtfile variable.
*/ #define BOOTENV_EFI_SET_FDTFILE_FALLBACK \ "if test -z "${fdtfile}" -a -n "${soc}"; then " \ "setenv efi_fdtfile ${soc}-${board}${boardver}.dtb; " \ "fi; " #else #define BOOTENV_EFI_SET_FDTFILE_FALLBACK #endif
that schema is not true on AArch64 and the method only works with efi booting. I will update the text to list out the conditions you could get away with not setting the variable
I was thinking more of cmd/pxe_utils.c:label_boot(), which covers the extlinux.conf rather then EFI case. This certainly applies to both 32- and 64-bit Tegra systems at least.
Specifically:
f1 = env_get("fdtfile"); if (f1) { f2 = ""; f3 = ""; f4 = ""; } else { /* * For complex cases where this code doesn't * generate the correct filename, the board * code should set $fdtfile during early boot, * or the boot scripts should set $fdtfile * before invoking "pxe" or "sysboot". */ f1 = env_get("soc"); f2 = "-"; f3 = env_get("board"); f4 = ".dtb"; }