Re: [PATCH] powerpc/powernv/flash: Check OPAL flash calls exist before using

On 9/15/21 11:53 AM, Michael Ellerman wrote:

Vasant Hegde [off-list ref] writes:

quoted

Currently only FSP based powernv systems supports firmware update
interfaces. Hence check that the token OPAL_FLASH_VALIDATE exists
before initalising the flash driver.

Signed-off-by: Vasant Hegde <redacted>
---
  arch/powerpc/platforms/powernv/opal-flash.c | 4 ++++
  1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/opal-flash.c b/arch/powerpc/platforms/powernv/opal-flash.c
index 7e7d38b17420..05490fc22fae 100644
--- a/arch/powerpc/platforms/powernv/opal-flash.c
+++ b/arch/powerpc/platforms/powernv/opal-flash.c

@@ -520,6 +520,10 @@ void __init opal_flash_update_init(void)
  {
  	int ret;
  
+	/* Firmware update is not supported by firmware */
+	if (!opal_check_token(OPAL_FLASH_VALIDATE))
+		return;
+

Michael,

That will mean the following files no longer appear on BMC systems:

   /sys/firmware/opal/image
   /sys/firmware/opal/validate_flash
   /sys/firmware/opal/manage_flash
   /sys/firmware/opal/update_flash

Presumably those files don't actually work correctly, but are we sure
their mere existence isn't used by anything at all?

That's correct. We never used these files/interfaces on BMC based systems.

We've had trouble in the past where removing sysfs files breaks tools
unexpectedly, see smt_snooze_delay.

AFAIK only update_flash uses these interfaces on baremetal systems.
This change shouldn't break update_flash as these interfaces never used/worked
on BMC based powernv systems.

-Vasant