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: remove PT_OFFSET to avoid redefnition

Building on ARCH=um causes a "redefined" warning, so remove this
PT_OFFSET macro to avoid the warning.

drivers/dma/ptdma/ptdma.h:34: warning: "PT_OFFSET" redefined
34 | #define PT_OFFSET 0x0
|
In file included from ./arch/um/include/asm/thread_info.h:17,
from ./include/linux/thread_info.h:60,
from ./include/asm-generic/preempt.h:5,
from ./arch/um/include/generated/asm/preempt.h:1,
from ./include/linux/preempt.h:78,
from ./include/linux/spinlock.h:55,
from ./include/linux/wait.h:9,
from ./include/linux/wait_bit.h:8,
from ./include/linux/fs.h:6,
from ./include/linux/debugfs.h:15,
from drivers/dma/ptdma/ptdma-debugfs.c:12:
./arch/x86/um/shared/sysdep/ptrace_user.h:4: note: this is the location of the previous definition
4 | #define PT_OFFSET(r) ((r) * sizeof(long))

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 2a99524459ce ("dmaengine: ptdma: Initial driver for the AMD PTDMA")
Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
Link: https://lore.kernel.org/r/1630178908-54973-1-git-send-email-Sanju.Mehta@amd.com
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>