spi: qcom-geni: Add panic notifier to cancel and reset DMA during panic

When a VM crashes with an active SPI DMA transfer in progress, the
SMMU raises context faults as the DMA engine continues to access
IOVAs that are invalidated when the VM's memory context is torn down.
These faults can affect other VMs sharing the same SMMU instance and
obscure the root cause of the crash.

Register a panic notifier that cancels (or aborts, if cancel doesn't
complete) the in-flight command and resets the TX/RX DMA FSMs, so the
DMA engine stops issuing transactions against invalidated IOVAs
before the system halts. For GPI DMA mode, the DMA channels are
terminated directly via dmaengine_terminate_async().

The notifier bails out early if the device is not runtime-active or
if there's no active GENI command, avoiding unnecessary register
accesses while the SE is clock-gated or idle.

Since panic notifiers run with IRQs and preemption disabled,
completion-based waits used by the regular error-handling path
(handle_se_timeout()) cannot be reused here. Instead, the relevant
status registers are polled directly with
readl_poll_timeout_atomic(), which is safe to call in this context.

Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>
Link: https://patch.msgid.link/20260818-add-shutdown-and-panic-notifier-for-spi-v3-2-8b62c4bc2d21@oss.qualcomm.com
Signed-off-by: Mark Brown <broonie@kernel.org>

0 files changed, 0 insertions, 0 deletions