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

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;
+
 	/* Allocate validate image buffer */
 	validate_flash_data.buf = kzalloc(VALIDATE_BUF_SIZE, GFP_KERNEL);
 	if (!validate_flash_data.buf) {

-- 
2.31.1

Vasant Hegde [off-list ref] writes:

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?

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

cheers

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

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

On Tue, 14 Sep 2021 15:46:30 +0530, Vasant Hegde wrote:

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

Applied to powerpc/next.

[1/1] powerpc/powernv/flash: Check OPAL flash calls exist before using
      https://git.kernel.org/powerpc/c/25e69962efdbbbd8bf52e6b4d7852c49717923a2

cheers