On Tue, 1 Apr 2025 09:57:10 +0200
Boris Brezillon <boris.brezil...@collabora.com> wrote:
> MMU handler needs to be in control of the job interrupt clears because
> clearing the interrupt also unblocks the writer/reader that triggered
> the fault, and we don't want it to be unblocked until we've had a chance
> to process the IRQ.
>
> Since clearing the clearing is just one line, let's make it explicit
> instead of doing it in the generic code path.
>
> Signed-off-by: Boris Brezillon <boris.brezil...@collabora.com>
> ---
> drivers/gpu/drm/panthor/panthor_device.h | 2 --
> drivers/gpu/drm/panthor/panthor_fw.c | 2 ++
> drivers/gpu/drm/panthor/panthor_gpu.c | 2 ++
> drivers/gpu/drm/panthor/panthor_mmu.c | 2 ++
> 4 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_device.h
> b/drivers/gpu/drm/panthor/panthor_device.h
> index da6574021664..4c27b6d85f46 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.h
> +++ b/drivers/gpu/drm/panthor/panthor_device.h
> @@ -383,8 +383,6 @@ static irqreturn_t panthor_ ## __name ##
> _irq_threaded_handler(int irq, void *da
> if (!status)
> \
> break;
> \
>
> \
> - gpu_write(ptdev, __reg_prefix ## _INT_CLEAR, status);
> \
> -
> \
> __handler(ptdev, status);
> \
> ret = IRQ_HANDLED;
> \
> }
> \
> diff --git a/drivers/gpu/drm/panthor/panthor_fw.c
> b/drivers/gpu/drm/panthor/panthor_fw.c
> index 0f52766a3120..446bb377b953 100644
> --- a/drivers/gpu/drm/panthor/panthor_fw.c
> +++ b/drivers/gpu/drm/panthor/panthor_fw.c
> @@ -1008,6 +1008,8 @@ static void panthor_fw_init_global_iface(struct
> panthor_device *ptdev)
>
> static void panthor_job_irq_handler(struct panthor_device *ptdev, u32 status)
> {
> + gpu_write(ptdev, JOB_INT_CLEAR, status);
> +
> if (!ptdev->fw->booted && (status & JOB_INT_GLOBAL_IF))
> ptdev->fw->booted = true;
>
> diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c
> b/drivers/gpu/drm/panthor/panthor_gpu.c
> index 671049020afa..32d678a0114e 100644
> --- a/drivers/gpu/drm/panthor/panthor_gpu.c
> +++ b/drivers/gpu/drm/panthor/panthor_gpu.c
> @@ -150,6 +150,8 @@ static void panthor_gpu_init_info(struct panthor_device
> *ptdev)
>
> static void panthor_gpu_irq_handler(struct panthor_device *ptdev, u32 status)
> {
> + gpu_write(ptdev, GPU_INT_CLEAR, status);
> +
> if (status & GPU_IRQ_FAULT) {
> u32 fault_status = gpu_read(ptdev, GPU_FAULT_STATUS);
> u64 address = ((u64)gpu_read(ptdev, GPU_FAULT_ADDR_HI) << 32) |
> diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c
> b/drivers/gpu/drm/panthor/panthor_mmu.c
> index 7cca97d298ea..1ecb20bfbc92 100644
> --- a/drivers/gpu/drm/panthor/panthor_mmu.c
> +++ b/drivers/gpu/drm/panthor/panthor_mmu.c
> @@ -1669,6 +1669,8 @@ static void panthor_mmu_irq_handler(struct
> panthor_device *ptdev, u32 status)
> {
> bool has_unhandled_faults = false;
>
> + gpu_write(ptdev, MMU_INT_CLEAR, status);
Actually, this one was meant to be moved inside the loop, and be a
per-AS clear. I'll fix that in v2.
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -1710,6 +1710,11 @@ static void panthor_mmu_irq_handler(struct
panthor_device *ptdev, u32 status) access_type, access_type_name(ptdev,
fault_status), source_id);
+ /* We don't handle VM faults at the moment, so let's just clear
the
+ * interrupt and let the writer/reader crash.
+ */
+ gpu_write(ptdev, MMU_INT_CLEAR, mask);
+
/* Ignore MMU interrupts on this AS until it's been
* re-enabled.
*/
