[PATCH 0/3] HID: Intel-thc-hid: Refine error recovery flow

[Even Xu <even.xu@intel.com>]

This series refines the fatal error recovery flow for the Intel THC
(Touch Host Controller) subsystem, covering both the QuickI2C and
QuickSPI drivers.

Currently, when a fatal DMA error is detected in the IRQ thread handler,
the recovery is performed inline: the interrupt handler calls
try_recover() directly, which unconfigures and reconfigures the DMA
engine.

This approach has several problems:
1. Recovery runs in the IRQ thread context, which is not ideal for
   potentially slow reset operations.
2. The interrupt is re-enabled before recovery completes, risking an
   interrupt storm if DMA errors persist.
3. The DMA reset logic is open-coded in each protocol driver, leading
   to duplication and divergence over time.

This patch series addresses all of the above:

By adding a new thc_rxdma_reset() API to the THC core layer, QuickI2C
and QuickSPI drivers can call it respectively to refine the recovery
callback.

The synchronous try_recover() call in the IRQ thread is replaced with
schedule_work(), deferring recovery to a workqueue.  Within the work
function:
- The interrupt line is disabled before any DMA manipulation.
- thc_rxdma_reset() is used instead of the open-coded sequence.
- On failure the device is marked DISABLED and the interrupt remains
  off, preventing an interrupt storm.

Even Xu (3):
  HID: Intel-thc-hid: Intel-thc: Add API to reset read DMA
  HID: Intel-thc-hid: Intel-quicki2c: Refine recover callback
  HID: Intel-thc-hid: Intel-quickspi: Refine recover callback

 .../intel-quicki2c/pci-quicki2c.c             | 31 +++++++---------
 .../intel-quicki2c/quicki2c-dev.h             |  2 +
 .../intel-quickspi/pci-quickspi.c             | 37 +++++++------------
 .../intel-quickspi/quickspi-dev.h             |  2 +
 .../intel-thc-hid/intel-thc/intel-thc-dma.c   | 37 +++++++++++++++++++
 .../intel-thc-hid/intel-thc/intel-thc-dma.h   |  1 +
 6 files changed, 68 insertions(+), 42 deletions(-)

-- 
2.43.0