The sanity check previously added to uaudio_transfer_buffer_setup()
assumed the allocated buffer being linear-mapped. But the buffer
allocated via usb_alloc_coherent() isn't always so, rather to be used
with (SG-)DMA API. This leaded to a false-positive warning and the
driver failed to work.
Actually uaudio_transfer_buffer_setup() deals only with the DMA-API
addresses for MEM_XFER_BUF type, while other callers of
uaudio_iommu_map() are with pages with physical addresses for
MEM_EVENT_RING and MEM_XFER_RING types. So this patch splits the
mapping helper function to two different ones, uaudio_iommu_map() for
the DMA pages and uaudio_iommu_map_pa() for the latter, in order to
handle mapping differently for each type. Along with it, the
unnecessary address check that caused probe error is dropped, too.
Fixes: 3335a1bbd6 ("ALSA: qc_audio_offload: try to reduce address space confusion")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reported-and-tested-by: Luca Weiss <luca.weiss@fairphone.com>
Closes: https://lore.kernel.org/DBR2363A95M1.L9XBNC003490@fairphone.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
44499ecb4f