dmaengine: ptdma: use consistent DMA masks

The PTDMA driver sets DMA masks in two different places for the same
device inconsistently. First call is in pt_pci_probe(), where it uses
48bit mask. The second call is in pt_dmaengine_register(), where it
uses a 64bit mask. Using 64bit dma mask causes IO_PAGE_FAULT errors
on DMA transfers between main memory and other devices.
Without the extra call it works fine. Additionally the second call
doesn't check the return value so it can silently fail.
Remove the superfluous dma_set_mask() call and only use 48bit mask.

Cc: stable@vger.kernel.org
Fixes: b0b4a6b10577 ("dmaengine: ptdma: register PTDMA controller as a DMA resource")
Reviewed-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Tadeusz Struk <tstruk@gigaio.com>
Link: https://lore.kernel.org/r/20240222163053.13842-1-tstruk@gigaio.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: ptdma: check for null desc before calling pt_cmd_callback

Resolves a panic that can occur on AMD systems, typically during host
shutdown, after the PTDMA driver had been exercised. The issue was
the pt_issue_pending() function is mistakenly assuming that there will
be at least one descriptor in the Submitted queue when the function
is called. However, it is possible that both the Submitted and Issued
queues could be empty, which could result in pt_cmd_callback() being
mistakenly called with a NULL pointer.
Ref: Bugzilla Bug 216856.

Fixes: 6fa7e0e836e2 ("dmaengine: ptdma: fix concurrency issue with multiple dma transfer")
Signed-off-by: Eric Pilmore <epilmore@gigaio.com>
Link: https://lore.kernel.org/r/20230210075142.58253-1-epilmore@gigaio.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: ptdma: statify pt_tx_status

LKP bot reports a new warning:
Warning:
drivers/dma/ptdma/ptdma-dmaengine.c:262:1: warning: no previous prototype for 'pt_tx_status' [-Wmissing-prototypes]

pt_tx_status() should be static, so declare as such.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: d965068259d1 ("dmaengine: PTDMA: support polled mode")
Link: https://lore.kernel.org/r/20220421052407.745637-1-vkoul@kernel.org
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: handle the cases based on DMA is complete

There is a need to segregate the cases when DMA is complete or not.
In case if DMA is already complete there is no need to handle it
again and gracefully exit from the function.

Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
Link: https://lore.kernel.org/r/1643814880-3882-3-git-send-email-Sanju.Mehta@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

dmaengine: ptdma: fix concurrency issue with multiple dma transfer

The command should be submitted only if the engine is idle,
for this, the next available descriptor is checked and set the flag
to false in case the descriptor is non-empty.

Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
Link: https://lore.kernel.org/r/1643814880-3882-2-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>