ptdma: pt_core_execute_cmd() should use spinlock

The interrupt handler (pt_core_irq_handler()) of the ptdma
driver can be called from interrupt context. The code flow
in this function can lead down to pt_core_execute_cmd() which
will attempt to grab a mutex, which is not appropriate in
interrupt context and ultimately leads to a kernel panic.
The fix here changes this mutex to a spinlock, which has
been verified to resolve the issue.

Fixes: fa5d823b16a9 ("dmaengine: ptdma: Initial driver for the AMD PTDMA")
Signed-off-by: Eric Pilmore <epilmore@gigaio.com>
Link: https://lore.kernel.org/r/20230119033907.35071-1-epilmore@gigaio.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: PTDMA: support polled mode

If the DMA_PREP_INTERRUPT flag is not provided, run in polled mode,
which significantly improves IOPS: more than twice on chunks < 4K.

Signed-off-by: Ilya Novikov <i.m.novikov@yadro.com>
Link: https://lore.kernel.org/r/20220413113733.59041-1-i.m.novikov@yadro.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: ptdma: Fix the error handling path in pt_core_init()

In order to free resources correctly in the error handling path of
pt_core_init(), 2 goto's have to be switched. Otherwise, some resources
will leak and we will try to release things that have not been allocated
yet.

Also move a dev_err() to a place where it is more meaningful.

Fixes: fa5d823b16a9 ("dmaengine: ptdma: Initial driver for the AMD PTDMA")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Sanjay R Mehta <sanju.mehta@amd.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/41a963a35173f89c874f5c44df5530dc09fea8da.1644044244.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: ptdma: Add debugfs entries for PTDMA

Expose data about the configuration and operation of the
PTDMA through debugfs entries: device name, capabilities,
configuration, statistics.

Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
Link: https://lore.kernel.org/r/1629208559-51964-4-git-send-email-Sanju.Mehta@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: ptdma: register PTDMA controller as a DMA resource

Register ptdma queue to Linux dmaengine framework as general-purpose
DMA channels.

Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
Link: https://lore.kernel.org/r/1629208559-51964-3-git-send-email-Sanju.Mehta@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: ptdma: Initial driver for the AMD PTDMA

Add support for AMD PTDMA controller. It performs high-bandwidth
memory to memory and IO copy operation. Device commands are managed
via a circular queue of 'descriptors', each of which specifies source
and destination addresses for copying a single buffer of data.

Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
Link: https://lore.kernel.org/r/1629208559-51964-2-git-send-email-Sanju.Mehta@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>