[PATCH 1/1] riscv: enable reset via SBI on PolarFire Icicle Kit

[Heinrich Schuchardt]

On 11/8/22 15:16, Conor Dooley wrote:
> On Mon, Nov 07, 2022 at 10:55:46AM +0100, Heinrich Schuchardt wrote:
>> HSS 2022.10 provides support for resetting the board.
> 
> It's actually v2022.09 that added support for reset. I don't think that
> that is important to correct though, since v2022.10 is the version we
> are updating the dt in U-Boot to match.
> Reviewed-by: Conor Dooley <conor.dooley at microchip.com>
> 
> One minor & mostly unrelated question below.
> 
>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
>> ---
>>   configs/microchip_mpfs_icicle_defconfig | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/configs/microchip_mpfs_icicle_defconfig b/configs/microchip_mpfs_icicle_defconfig
>> index c295b9bad3..65bd50db80 100644
>> --- a/configs/microchip_mpfs_icicle_defconfig
>> +++ b/configs/microchip_mpfs_icicle_defconfig
>> @@ -21,3 +21,5 @@ CONFIG_SYS_MEM_TOP_HIDE=0x400000
>>   CONFIG_SYS_RELOC_GD_ENV_ADDR=y
>>   CONFIG_BOOTP_SEND_HOSTNAME=y
>>   CONFIG_DM_MTD=y
>> +CONFIG_SYSRESET=y
>> +CONFIG_SYSRESET_SBI=y
> 
> I took a look at the config option, but something seemed odd to me. It
> says "depends on SBI_V02" but the help text says "version 0.3". I see
> there's no define for SBI_V03 so I assume that's why there's a mismatch.
> 
> I didn't see a comment about it in the commit hence asking. AFAIR, v0.3
> is the correct version.

The only ratified version of the SBI specification is 1.0.

v0.2 introduced the concept of extensions.
v0.3 introduced the SRST extension.

CONFIG_SBI_V02=y means SBI specification v0.2 or later. We should update 
the description of CONFIG_SBI_V02 accordingly.

HSS 2022.10 provides an OpenSBI 1.0 which is good enough.

If you use a 0.1 or 0.2 SBI, the worst thing that can happen is that 
sbi_probe_extension(SBI_EXT_SRST) will return an error and the reset 
driver is not loaded.

Best regards

Heinrich

> 
>> config SYSRESET_SBI
>> 	bool "Enable support for SBI System Reset"
>> 	depends on RISCV_SMODE && SBI_V02
>> 	default y
>> 	select SYSRESET_CMD_POWEROFF if CMD_POWEROFF
>> 	help
>> 	  Enable system reset and poweroff via the SBI system reset extension.
>> 	  The extension was introduced in version 0.3 of the SBI specification.