[PATCH v2 09/11] dmaengine: xilinx_dpdma: stop using slave_id field

Arnd Bergmann
2021-11-22T22:41:20Z

The display driver wants to pass a custom flag to the DMA engine driver,
which it started doing by using the slave_id field that was traditionally
used for a different purpose.

As there is no longer a correct use for the slave_id field, it should
really be removed, and the remaining users changed over to something
different.

The new mechanism for passing nonstandard settings is using the
.peripheral_config field, so use that to pass a newly defined structure
here, making it clear that this will not work in portable drivers.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/dma/xilinx/xilinx_dpdma.c | 17 +++++++++++------
drivers/gpu/drm/xlnx/zynqmp_disp.c | 9 +++++++--
include/linux/dma/xilinx_dpdma.h | 11 +++++++++++
3 files changed, 29 insertions(+), 8 deletions(-)
create mode 100644 include/linux/dma/xilinx_dpdma.h

diff --git a/drivers/dma/xilinx/xilinx_dpdma.c b/drivers/dma/xilinx/xilinx_dpdma.c
index ce5c66e6897d..b0f4948b00a5 100644
--- a/drivers/dma/xilinx/xilinx_dpdma.c
+++ b/drivers/dma/xilinx/xilinx_dpdma.c
@@ -12,6 +12,7 @@
#include <linux/clk.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
+#include <linux/dma/xilinx_dpdma.h>
#include <linux/dmaengine.h>
#include <linux/dmapool.h>
#include <linux/interrupt.h>
@@ -1273,6 +1274,7 @@ static int xilinx_dpdma_config(struct dma_chan *dchan,
struct dma_slave_config *config)
{
struct xilinx_dpdma_chan *chan = to_xilinx_chan(dchan);
+ struct xilinx_dpdma_peripheral_config *pconfig;
unsigned long flags;

/*
@@ -1282,15 +1284,18 @@ static int xilinx_dpdma_config(struct dma_chan *dchan,
* fixed both on the DPDMA side and on the DP controller side.
*/

- spin_lock_irqsave(&chan->lock, flags);
-
/*
- * Abuse the slave_id to indicate that the channel is part of a video
- * group.
+ * Use the peripheral_config to indicate that the channel is part
+ * of a video group. This requires matching use of the custom
+ * structure in each driver.
*/
- if (chan->id <= ZYNQMP_DPDMA_VIDEO2)
- chan->video_group = config->slave_id != 0;
+ pconfig = config->peripheral_config;
+ if (WARN_ON(pconfig && config->peripheral_size != sizeof(*pconfig)))
+ return -EINVAL;

+ spin_lock_irqsave(&chan->lock, flags);
+ if (chan->id <= ZYNQMP_DPDMA_VIDEO2 && pconfig)
+ chan->video_group = pconfig->video_group;
spin_unlock_irqrestore(&chan->lock, flags);

return 0;
diff --git a/drivers/gpu/drm/xlnx/zynqmp_disp.c b/drivers/gpu/drm/xlnx/zynqmp_disp.c
index ff2b308d8651..11c409cbc88e 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_disp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_disp.c
@@ -24,6 +24,7 @@

#include <linux/clk.h>
#include <linux/delay.h>
+#include <linux/dma/xilinx_dpdma.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/module.h>
@@ -1058,14 +1059,18 @@ static void zynqmp_disp_layer_set_format(struct zynqmp_disp_layer *layer,
zynqmp_disp_avbuf_set_format(layer->disp, layer, layer->disp_fmt);

/*
- * Set slave_id for each DMA channel to indicate they're part of a
+ * Set pconfig for each DMA channel to indicate they're part of a
* video group.
*/
for (i = 0; i < info->num_planes; i++) {
struct zynqmp_disp_layer_dma *dma = &layer->dmas[i];
+ struct xilinx_dpdma_peripheral_config pconfig = {
+ .video_group = true,
+ };
struct dma_slave_config config = {
.direction = DMA_MEM_TO_DEV,
- .slave_id = 1,
+ .peripheral_config = &pconfig,
+ .peripheral_size = sizeof(pconfig),
};

dmaengine_slave_config(dma->chan, &config);
diff --git a/include/linux/dma/xilinx_dpdma.h b/include/linux/dma/xilinx_dpdma.h
new file mode 100644
index 000000000000..83a1377f03f8
--- /dev/null
+++ b/include/linux/dma/xilinx_dpdma.h
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef __LINUX_DMA_XILINX_DPDMA_H
+#define __LINUX_DMA_XILINX_DPDMA_H
+
+#include <linux/types.h>
+
+struct xilinx_dpdma_peripheral_config {
+ bool video_group;
+};
+
+#endif /* __LINUX_DMA_XILINX_DPDMA_H */