On 11/4/23 19:13, Andre Przywara wrote:
On Sat, 4 Nov 2023 09:00:07 +0200 Heinrich Schuchardt heinrich.schuchardt@canonical.com wrote:
Hi Heinrich,
many thanks for finding and fixing this!
In different parts of our code we assume that the first RNG device is the one to be used. Therefore it is preferable to detect the availability of the RNDR register already in the bind method.
For signaling the non-existence of a device the driver model requires using ENOENT (and not ENODEV).
Doh, now I feel silly! I thought I checked the call path, and looked at initcall_run_list(), which prints the error message, and suggests that only 0 would be acceptable. But indeed -ENOENT works, with the slight caveat of printing: ================ No match for driver 'arm-rndr' Some drivers were not found
The message texts are definitively wrong. They should be:
No device for driver 'arm-rndr'. Some devices not found.
@Simon
I think we should make these messages log_debug().
Best regards
Heinrich
================
But it's definitely an improvement over the current situation, and I don't feel like boiling the DM ocean for this stupid little driver.
Fixes: 31565bb0aa2d ("driver: rng: Add DM_RNG interface for ARMv8.5 RNDR registers") Signed-off-by: Heinrich Schuchardt> heinrich.schuchardt@canonical.com
Reviewed-by: Andre Przywara andre.przywara@arm.com Tested-by: Andre Przywara andre.przywara@arm.com
Many thanks! Andre
drivers/rng/arm_rndr.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/rng/arm_rndr.c b/drivers/rng/arm_rndr.c index 55989743ea..4512330e68 100644 --- a/drivers/rng/arm_rndr.c +++ b/drivers/rng/arm_rndr.c @@ -62,10 +62,10 @@ static const struct dm_rng_ops arm_rndr_ops = { .read = arm_rndr_read, };
-static int arm_rndr_probe(struct udevice *dev) +static int arm_rndr_bind(struct udevice *dev) { if (!cpu_has_rndr())
return -ENODEV;
return -ENOENT;return 0; }
@@ -74,7 +74,7 @@ U_BOOT_DRIVER(arm_rndr) = { .name = DRIVER_NAME, .id = UCLASS_RNG, .ops = &arm_rndr_ops,
- .probe = arm_rndr_probe,
.bind = arm_rndr_bind, };
U_BOOT_DRVINFO(cpu_arm_rndr) = {