[PATCH 2/3] accel/ethosu: propagate SRAM initialization errors

[zhaoguohan]

From: GuoHan Zhao <zhaoguohan@xxxxxxxxxx>

ethosu_sram_init() returns -ENOMEM if allocation from a declared SRAM
pool fails. ethosu_init() ignores the error after recording the pool size.
Probe then registers a device with a nonzero SRAM size and a zero sramphys
address, allowing jobs to program address zero for SRAM.

Propagate the error and synchronously suspend the device before the probe
path releases the scheduler.

Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver")
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Sashiko <sashiko-bot@xxxxxxxxxx>
Link: https://sashiko.dev/#/patchset/20260716065219.931088-1-zhaoguohan@xxxxxxxxxx?part=1
Signed-off-by: GuoHan Zhao <zhaoguohan@xxxxxxxxxx>
---
Sashiko report:

> This is a pre-existing issue, but was not introduced by this patch.
>
> In ethosu_sram_init(), if gen_pool_dma_alloc() fails, it returns an
> error. However, ethosu_init() ignores this return value.
>
> Because npu_info.sram_size was already set to gen_pool_size(), it remains
> non-zero while sramphys remains 0.
>
> When a user submits a job requesting sram, the size check passes, and
> ethosu_job_hw_submit() configures the hardware to use physical sram
> address 0x0.
>
> Could this result in a memory corruption regression or an IOMMU fault?

 drivers/accel/ethosu/ethosu_drv.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/accel/ethosu/ethosu_drv.c b/drivers/accel/ethosu/ethosu_drv.c
index d1153b15ca3e..479156f79bc1 100644
--- a/drivers/accel/ethosu/ethosu_drv.c
+++ b/drivers/accel/ethosu/ethosu_drv.c
@@ -320,7 +320,9 @@ static int ethosu_init(struct ethosu_device *ethosudev)
 	ethosudev->npu_info.id = id = readl_relaxed(ethosudev->regs + NPU_REG_ID);
 	ethosudev->npu_info.config = config = readl_relaxed(ethosudev->regs + NPU_REG_CONFIG);
 
-	ethosu_sram_init(ethosudev);
+	ret = ethosu_sram_init(ethosudev);
+	if (ret)
+		goto err_runtime_suspend;
 
 	dev_info(ethosudev->base.dev,
 		 "Ethos-U NPU, arch v%ld.%ld.%ld, rev r%ldp%ld, cmd stream ver%ld, %d MACs, %dKB SRAM\n",
@@ -335,6 +337,10 @@ static int ethosu_init(struct ethosu_device *ethosudev)
 
 	return 0;
 
+err_runtime_suspend:
+	pm_runtime_dont_use_autosuspend(ethosudev->base.dev);
+	pm_runtime_put_sync_suspend(ethosudev->base.dev);
+	return ret;
 err_suspend:
 	pm_runtime_dont_use_autosuspend(ethosudev->base.dev);
 	ethosu_device_suspend(ethosudev->base.dev);
-- 
2.43.0