ata: pata_ep93xx: fix PIO fallback when DMA init fails

ep93xx_pata_dma_init() returns an error when dma_request_chan() fails,
which causes ep93xx_pata_probe() to abort entirely.  The probe function
already has a PIO fallback path (it checks both channel pointers before
enabling UDMA), so the DMA init should not fail the probe on non-fatal
errors.

Propagate -EPROBE_DEFER, such that we allow the DMA controller driver
to load, in case we got probed before the DMA controller driver.
For all other failures (e.g. -ENODEV when the DMA controller is missing
in the device tree), fall back to PIO.

Assisted-by: Opencode:Big-Pickle
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>

0 files changed, 0 insertions, 0 deletions