A single AXIDMA controller can have one or two channels. When it has two
channels, the reset for both are tied together: resetting one channel
resets the other as well. This creates a problem where resetting one
channel will reset the registers for both channels, including clearing
interrupt enable bits for the other channel, which can then lead  to
timeouts as the driver is waiting for an interrupt which never comes.

The driver currently has a probe-time work around for this: when a
channel is created, the driver also resets and enables the
interrupts. With two channels the reset for the second channel will
clear the interrupt enables for the first one. The work around in the
driver is just to manually enable the interrupts again in
xilinx_dma_alloc_chan_resources().

This workaround only addresses the probe-time issue. When channels are
reset at runtime (e.g., in xilinx_dma_terminate_all() or during error
recovery), there's no corresponding mechanism to restore the other
channel's interrupt enables. This leads to one channel having its
interrupts disabled while the driver expects them to work, causing
timeouts and DMA failures.

A proper fix is a complicated matter, as we should not reset the other
channel when it's operating normally. So, perhaps, there should be some
kind of synchronization for a common reset, which is not trivial to
implement. To add to the complexity, the driver also supports other DMA
types, like VDMA, CDMA and MCDMA, which don't have a shared reset.

However, when the two-channel AXIDMA is used in the (assumably) normal
use case, providing DMA for a single memory-to-memory device, the common
reset is a bit smaller issue: when something bad happens on one channel,
or when one channel is terminated, the assumption is that we also want
to terminate the other channel. And thus resetting both at the same time
is "ok".

With that line of thinking we can implement a bit better work around
than just the current probe time work around: let's enable the
AXIDMA interrupts at xilinx_dma_start_transfer() instead.
This ensures interrupts are enabled whenever a transfer starts,
regardless of any prior resets that may have cleared them.

This approach is also more logical: enable interrupts only when needed
for a transfer, rather than at resource allocation time, and, I think,
all the other DMA types should also use this model, but I'm reluctant to
do such changes as I cannot test them.

The reset function still enables interrupts even though it's not needed
for AXIDMA anymore, but it's common code for all DMA types (VDMA, CDMA,
MCDMA), so leave it unchanged to avoid affecting other variants.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Fixes: c0bba3a99f07 ("dmaengine: vdma: Add Support for Xilinx AXI Direct Memory Access Engine")
Link: https://patch.msgid.link/20260311-xilinx-dma-fix-v2-1-a725abb66e3c@ideasonboard.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

The segment .control and .status fields both contain top bits which are
not part of the buffer size, the buffer size is located only in the bottom
max_buffer_len bits. To avoid interference from those top bits, mask out
the size using max_buffer_len first, and only then subtract the values.

Fixes: a575d0b4e663 ("dmaengine: xilinx_dma: Introduce xilinx_dma_get_residue")
Signed-off-by: Marek Vasut <marex@nabladev.com>
Link: https://patch.msgid.link/20260316222530.163815-1-marex@nabladev.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

The cyclic DMA calculation is currently entirely broken and reports
residue only for the first segment. The problem is twofold.

First, when the first descriptor finishes, it is moved from active_list
to done_list, but it is never returned back into the active_list. The
xilinx_dma_tx_status() expects the descriptor to be in the active_list
to report any meaningful residue information, which never happens after
the first descriptor finishes. Fix this up in xilinx_dma_start_transfer()
and if the descriptor is cyclic, lift it from done_list and place it back
into active_list list.

Second, the segment .status fields of the descriptor remain dirty. Once
the DMA did one pass on the descriptor, the .status fields are populated
with data by the DMA, but the .status fields are not cleared before reuse
during the next cyclic DMA round. The xilinx_dma_get_residue() recognizes
that as if the descriptor was complete and had 0 residue, which is bogus.
Reinitialize the status field before placing the descriptor back into the
active_list.

Fixes: c0bba3a99f07 ("dmaengine: vdma: Add Support for Xilinx AXI Direct Memory Access Engine")
Signed-off-by: Marek Vasut <marex@nabladev.com>
Link: https://patch.msgid.link/20260316221943.160375-1-marex@nabladev.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Unlike chan->direction , struct dma_device .directions field is a
bitfield. Turn chan->direction into a bitfield to make it compatible
with struct dma_device .directions .

Fixes: 7e01511443c3 ("dmaengine: xilinx_dma: Set dma_device directions")
Signed-off-by: Marek Vasut <marex@nabladev.com>
Link: https://patch.msgid.link/20260316221728.160139-1-marex@nabladev.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Both rz_dmac_disable_hw() and rz_dmac_irq_handle_channel() update the
CHCTRL register. To avoid concurrency issues when configuring
functionalities exposed by this registers, take the virtual channel lock.
All other CHCTRL updates were already protected by the same lock.

Previously, rz_dmac_disable_hw() disabled and re-enabled local IRQs, before
accessing CHCTRL registers but this does not ensure race-free access.
Remove the local IRQ disable/enable code as well.

Fixes: 5000d37042a6 ("dmaengine: sh: Add DMAC driver for RZ/G2L SoC")
Cc: stable@vger.kernel.org
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://patch.msgid.link/20260316133252.240348-3-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

The driver lists (ld_free, ld_queue) are used in
rz_dmac_free_chan_resources(), rz_dmac_terminate_all(),
rz_dmac_issue_pending(), and rz_dmac_irq_handler_thread(), all under
the virtual channel lock. Take the same lock in rz_dmac_prep_slave_sg()
and rz_dmac_prep_dma_memcpy() as well to avoid concurrency issues, since
these functions also check whether the lists are empty and update or
remove list entries.

Fixes: 5000d37042a6 ("dmaengine: sh: Add DMAC driver for RZ/G2L SoC")
Cc: stable@vger.kernel.org
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://patch.msgid.link/20260316133252.240348-2-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

At the end of this function, d is the traversal cursor of flist, but the
code completes found instead. This can lead to issues such as NULL pointer
dereferences, double completion, or descriptor leaks.

Fix this by completing d instead of found in the final
list_for_each_entry_safe() loop.

Fixes: aa8d18becc0c ("dmaengine: idxd: add callback support for iaa crypto")
Signed-off-by: Tuo Li <islituo@gmail.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20260106032428.162445-1-islituo@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

devm_regmap_init_mmio returns an ERR_PTR() upon error, not NULL.
Fix the error check and also fix the error message. Use the error code
from ERR_PTR() instead of the wrong value in ret.

Fixes: 17ce252266c7 ("dmaengine: xilinx: xdma: Add xilinx xdma driver")
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20251014061309.283468-1-alexander.stein@ew.tq-group.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Others have submitted this issue (https://lore.kernel.org/dmaengine/
20240722030405.3385-1-zhengdongxiong@gxmicro.cn/),
but it has not been fixed yet. Therefore, more supplementary information
is provided here.

As mentioned in the "PCS-CCS-CB-TCB" Producer-Consumer Synchronization of
"DesignWare Cores PCI Express Controller Databook, version 6.00a":

1. The Consumer CYCLE_STATE (CCS) bit in the register only needs to be
initialized once; the value will update automatically to be
~CYCLE_BIT (CB) in the next chunk.
2. The Consumer CYCLE_BIT bit in the register is loaded from the LL
element and tested against CCS. When CB = CCS, the data transfer is
executed. Otherwise not.

The current logic sets customer (HDMA) CS and CB bits to 1 in each chunk
while setting the producer (software) CB of odd chunks to 0 and even
chunks to 1 in the linked list. This is leading to a mismatch between
the producer CB and consumer CS bits.

This issue can be reproduced by setting the transmission data size to
exceed one chunk. By the way, in the EDMA using the same "PCS-CCS-CB-TCB"
mechanism, the CS bit is only initialized once and this issue was not
found. Refer to
drivers/dma/dw-edma/dw-edma-v0-core.c:dw_edma_v0_core_start.

So fix this issue by initializing the CYCLE_STATE and CYCLE_BIT bits
only once.

Fixes: e74c39573d35 ("dmaengine: dw-edma: Add support for native HDMA")
Signed-off-by: LUO Haowen <luo-hw@foxmail.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/tencent_CB11AA9F3920C1911AF7477A9BD8EFE0AD05@qq.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

During the device remove process, the device is reset, causing the
configuration registers to go back to their default state, which is
zero. As the driver is checking if the event log support was enabled
before deallocating, it will fail if a reset happened before.

Do not check if the support was enabled, the check for 'idxd->evl'
being valid (only allocated if the HW capability is available) is
enough.

Fixes: 244da66cda35 ("dmaengine: idxd: setup event log configuration")
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Link: https://patch.msgid.link/20260121-idxd-fix-flr-on-kernel-queues-v3-v3-10-7ed70658a9d1@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>