From 215fdd4dc5fb377924a80e4e7b59b537fc6ed1c5 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Mon, 22 Nov 2021 23:22:01 +0100
Subject: dmaengine: xilinx_dpdma: stop using slave_id field
Git-commit: 93cdb5b0dc56cc7a8b87a61146495f3bdc93d7ba
Patch-mainline: v5.17-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

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>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211122222203.4103644-10-arnd@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Patrik Jakobsson <pjakobsson@suse.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 b280a53e8570..7de06743db32 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>
@@ -1286,6 +1287,7 @@ 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;
 
 	/*
@@ -1295,15 +1297,18 @@ 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 */
-- 
2.38.1