[U-Boot] [PATCH 1/2] efi_loader: Pass fdt address directly to bootefi cmd

[Alexander Graf <agraf@suse.de>]

On 14.04.16 00:26, Andreas F?rber wrote:
> Am 13.04.2016 um 23:22 schrieb Alexander Graf:
>> The bootefi cmd today fetches its device tree pointer from either the
>> location appointed by "fdt addr" with a fallback to the U-Boot control
>> fdt.
>>
>> This integration is unusual for U-Boot and diverges from the way we
>> usually handle parameters to boot commands. So let's pass the fdt
>> directly into the bootefi command instead and move the control fdt
>> logic into the distro boot script.
>>
>> Signed-off-by: Alexander Graf <agraf@suse.de>
>> ---
>>  cmd/bootefi.c                   | 34 +++++++++++++---------------------
>>  include/config_distro_bootcmd.h |  9 ++++++---
>>  2 files changed, 19 insertions(+), 24 deletions(-)
>>
>> diff --git a/cmd/bootefi.c b/cmd/bootefi.c
>> index b213ef1..ab39b95 100644
>> --- a/cmd/bootefi.c
>> +++ b/cmd/bootefi.c
>> @@ -142,12 +142,11 @@ static void *copy_fdt(void *fdt)
>>   * Load an EFI payload into a newly allocated piece of memory, register all
>>   * EFI objects it would want to access and jump to it.
>>   */
>> -static unsigned long do_bootefi_exec(void *efi)
>> +static unsigned long do_bootefi_exec(void *efi, void *fdt)
>>  {
>>  	ulong (*entry)(void *image_handle, struct efi_system_table *st);
>>  	ulong fdt_pages, fdt_size, fdt_start, fdt_end;
>>  	bootm_headers_t img = { 0 };
>> -	void *fdt = working_fdt;
>>  
>>  	/*
>>  	 * gd lives in a fixed register which may get clobbered while we execute
>> @@ -155,13 +154,7 @@ static unsigned long do_bootefi_exec(void *efi)
>>  	 */
>>  	efi_save_gd();
>>  
>> -	/* Update system table to point to our currently loaded FDT */
>> -
>> -	/* Fall back to included fdt if none was manually loaded */
>> -	if (!fdt && gd->fdt_blob)
>> -		fdt = (void *)gd->fdt_blob;
>> -
>> -	if (fdt) {
>> +	if (fdt && !fdt_check_header(fdt)) {
>>  		/* Prepare fdt for payload */
>>  		fdt = copy_fdt(fdt);
>>  
>> @@ -185,7 +178,7 @@ static unsigned long do_bootefi_exec(void *efi)
>>  		efi_add_memory_map(fdt_start, fdt_pages,
>>  				   EFI_BOOT_SERVICES_DATA, true);
>>  	} else {
>> -		printf("WARNING: No device tree loaded, expect boot to fail\n");
>> +		printf("WARNING: Invalid device tree, expect boot to fail\n");
>>  		systab.nr_tables = 0;
>>  	}
>>  
>> @@ -216,18 +209,20 @@ static unsigned long do_bootefi_exec(void *efi)
>>  /* Interpreter command to boot an arbitrary EFI image from memory */
>>  static int do_bootefi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>>  {
>> -	char *saddr;
>> -	unsigned long addr;
>> +	char *saddr, *sfdt;
>> +	unsigned long addr, fdt_addr;
>>  	int r = 0;
>>  
>> -	if (argc < 2)
>> +	if (argc < 3)
>>  		return 1;
> 
> Hm, I had specifically requested to make it an optional argument...
> do_bootefi_exec() seems to still handle !fdt, but here we seem to choke
> on absence of the third argument, not matching bootm/bootz/booti? GRUB
> does not need a DT to display its shell/menu, so we don't need to force
> it IMO. Think of people calling it from the prompt or from a script.
> 
> Or am I misunderstanding U-Boot argument handling?

I thought that Stephen's argument was that booting Linux without a
working device tree is moot anyway. I tend to agree ;).

If you really want to boot without a device tree, you can always just
pass in "-" as the fdt argument. But by requiring a device tree we
hopefully get less confused people using the uefi support.


Alex