[U-Boot] [PATCH v3 1/1] efi_loader: rework fdt handling in distro boot script

[Alexander Graf]

On 27.11.18 01:33, AKASHI Takahiro wrote:
> The current scenario for default UEFI booting, scan_dev_for_efi, has
> several issues:
> * load dtb dynamically even if its loacation (device) is not the same
>   as BOOTEFI_NAME binary's, (reported by Alex)
> * invoke 'bootmgr' only if BOOTEFI_NAME binary does exit even though
>   'bootmgr' can and should work independently whether or not the binary
>   exist,
> * in addition, invoke 'bootmgr' with dynamically-loaded dtb.
>   This behavior is not expected. (reported by Alex)
> * always assume that a 'fdtfile' variable is defined,
>   ("test -e ${devtype} ${devnum}:${distro_bootpart} "${prefix}${efi_fdtfile}"
>   always returns true even if fdtfile is NULL with prefix=="/".)
> * redundantly check for 'fdt_addr_r' in boot_efi_binary
> 
> In this patch, all the issues above are sorted out.
> Please note that the default behavior can be customized with:
> 	fdtfile: a dtb file name
> 	efi_dtb_prefixes: a list of paths for searching for a dtb file
> 
> (this feature does work even without this patch.)
> 
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> ---
>  include/config_distro_bootcmd.h | 38 +++++++++++++++++----------------
>  1 file changed, 20 insertions(+), 18 deletions(-)
> 
> diff --git a/include/config_distro_bootcmd.h b/include/config_distro_bootcmd.h
> index 373fee78a999..256698309eb9 100644
> --- a/include/config_distro_bootcmd.h
> +++ b/include/config_distro_bootcmd.h
> @@ -115,7 +115,7 @@
>   */
>  #define BOOTENV_EFI_SET_FDTFILE_FALLBACK                                  \
>  	"if test -z \"${fdtfile}\" -a -n \"${soc}\"; then "               \
> -	  "setenv efi_fdtfile ${soc}-${board}${boardver}.dtb; "           \
> +	  "efi_fdtfile=${soc}-${board}${boardver}.dtb; "           \
>  	"fi; "
>  #else
>  #define BOOTENV_EFI_SET_FDTFILE_FALLBACK
> @@ -124,26 +124,20 @@
>  
>  #define BOOTENV_SHARED_EFI                                                \
>  	"boot_efi_binary="                                                \
> -		"if fdt addr ${fdt_addr_r}; then "                        \
> -			"bootefi bootmgr ${fdt_addr_r};"                  \
> -		"else "                                                   \
> -			"bootefi bootmgr ${fdtcontroladdr};"              \
> -		"fi;"                                                     \
>  		"load ${devtype} ${devnum}:${distro_bootpart} "           \
>  			"${kernel_addr_r} efi/boot/"BOOTEFI_NAME"; "      \
> -		"if fdt addr ${fdt_addr_r}; then "                        \
> -			"bootefi ${kernel_addr_r} ${fdt_addr_r};"         \
> -		"else "                                                   \
> -			"bootefi ${kernel_addr_r} ${fdtcontroladdr};"     \
> -		"fi\0"                                                    \
> +		"bootefi ${kernel_addr_r} ${efi_fdt_addr};\0"		  \
>  	\
>  	"load_efi_dtb="                                                   \
> -		"load ${devtype} ${devnum}:${distro_bootpart} "           \
> -			"${fdt_addr_r} ${prefix}${efi_fdtfile}\0"         \
> +		"load ${devtype} ${devnum}:${distro_bootpart} "		  \
> +			"${fdt_addr_r} ${prefix}${efi_fdtfile}; "	  \
> +		"if fdt addr ${fdt_addr_r}; then "			  \
> +			"efi_fdt_addr=${fdt_addr_r}; "			  \
> +		"fi;\0"							  \
>  	\
>  	"efi_dtb_prefixes=/ /dtb/ /dtb/current/\0"                        \
> -	"scan_dev_for_efi="                                               \
> -		"setenv efi_fdtfile ${fdtfile}; "                         \
> +	"set_efi_fdt_addr="						  \
> +		"efi_fdtfile=${fdtfile}; "                         \
>  		BOOTENV_EFI_SET_FDTFILE_FALLBACK                          \
>  		"for prefix in ${efi_dtb_prefixes}; do "                  \
>  			"if test -e ${devtype} "                          \
> @@ -151,19 +145,26 @@
>  					"${prefix}${efi_fdtfile}; then "  \
>  				"run load_efi_dtb; "                      \
>  			"fi;"                                             \
> -		"done;"                                                   \
> +		"done;\0"                                                   \
> +	\
> +	"scan_dev_for_efi="                                               \
>  		"if test -e ${devtype} ${devnum}:${distro_bootpart} "     \
>  					"efi/boot/"BOOTEFI_NAME"; then "  \
>  				"echo Found EFI removable media binary "  \
>  					"efi/boot/"BOOTEFI_NAME"; "       \
> +				"efi_fdt_addr=${fdtcontroladdr}; "	  \
> +				"if test -n \"${fdtfile}\"; then "	  \
> +					"run set_efi_fdt_addr; "	  \
> +				"fi; "					  \
>  				"run boot_efi_binary; "                   \
>  				"echo EFI LOAD FAILED: continuing...; "   \
> -		"fi; "                                                    \
> -		"setenv efi_fdtfile\0"

This drops the bit that unsets the variable. So after the script, your
env will be different from before the script. Please run

  U-Boot# printenv
  U-Boot# boot (w/o any efi payload to boot)
  U-Boot# printenv

Then diff the two environments. They should be identical.


Alex