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

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

On Sun, Dec 02, 2018 at 11:58:45PM +0100, Alexander Graf wrote:
> 
> 
> 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@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.

Yeah, but

> 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.

Are you sure? When I try this on unmodified v2018.11,
I also see some difference:

18a19
> devnum=0
37a39
> scsi_need_init=false
44c46
< Environment size: 3614/65532 bytes
---
> Environment size: 3644/65532 bytes

It seems that 'devnum' and 'scsi_need_init' come from 'bootcmd_scsi0.'
Can you clarify your point a bit more, please?

Thanks,
-Takahiro Akashi

> 
> 
> Alex