In order to use this dmaengine with sound devices, let's add cyclic
transfers support. Most of the code is reused from the existing
scatter-gather implementation, only the final linking between
descriptors, the control fields (to trigger interrupts more often) and
the interrupt handling are really different.
This controller supports up to 32 adjacent descriptors, we assume this
is way more than enough for the purpose of cyclic transfers and limit to
32 the number of cycled descriptors. This way, we simplify a lot the
overall handling of the descriptors.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20231005160237.2804238-4-miquel.raynal@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.
To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new() which already returns void. Eventually after all drivers
are converted, .remove_new() is renamed to .remove().
Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230919133207.1400430-57-u.kleine-koenig@pengutronix.de
Signed-off-by: Vinod Koul <vkoul@kernel.org>
A couple of hardware registers need to be set to reflect which
interrupts have been allocated to the device. Each register is 32-bit
wide and can receive four 8-bit values. If we provide any other interrupt
number than four, the irq_num variable will never be 0 within the while
check and the while block will loop forever.
There is an easy way to prevent this: just break the for loop
when we reach "irq_num == 0", which anyway means all interrupts have
been processed.
Cc: stable@vger.kernel.org
Fixes: 17ce252266 ("dmaengine: xilinx: xdma: Add xilinx xdma driver")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Lizhi Hou <lizhi.hou@amd.com>
Link: https://lore.kernel.org/r/20230731101442.792514-2-miquel.raynal@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Add driver to enable PCIe board which uses XDMA (the DMA/Bridge Subsystem
for PCI Express). For example, Xilinx Alveo PCIe devices.
https://www.xilinx.com/products/boards-and-kits/alveo.html
The XDMA engine support up to 4 Host to Card (H2C) and 4 Card to Host (C2H)
channels. Memory transfers are specified on a per-channel basis in
descriptor linked lists, which the DMA fetches from host memory and
processes. Events such as descriptor completion and errors are signaled
using interrupts. The hardware detail is provided by
https://docs.xilinx.com/r/en-US/pg195-pcie-dma/Introduction
This driver implements dmaengine APIs.
- probe the available DMA channels
- use dma_slave_map for channel lookup
- use virtual channel to manage dmaengine tx descriptors
- implement device_prep_slave_sg callback to handle host scatter gather
list
- implement device_config to config device address for DMA transfer
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Signed-off-by: Sonal Santan <sonal.santan@amd.com>
Signed-off-by: Max Zhen <max.zhen@amd.com>
Signed-off-by: Brian Xu <brian.xu@amd.com>
Tested-by: Martin Tuma <tumic@gpxsee.org>
Link: https://lore.kernel.org/r/1674145926-29449-2-git-send-email-lizhi.hou@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
