[PATCH 5.10.y-cip 4/4] dmaengine: sh: rz-dmac: Add device_synchronize callback


Lad Prabhakar
 

From: Biju Das <biju.das.jz@...>

commit 7d3a3aaaa9cc8ec53e9ef4f3e1711827107f76c5 upstream.

Some on-chip peripheral modules(for eg:- rspi) on RZ/G2L SoC
use the same signal for both interrupt and DMA transfer requests.
The signal works as a DMA transfer request signal by setting
DMARS, and subsequent interrupt requests to the interrupt controller
are masked.

We can re-enable the interrupt by clearing the DMARS.

This patch adds device_synchronize callback for clearing
DMARS and thereby allowing DMA consumers to switch to
interrupt mode.

Signed-off-by: Biju Das <biju.das.jz@...>
Reviewed-by: Geert Uytterhoeven <geert+renesas@...>
Link: https://lore.kernel.org/r/20220722084430.969333-1-biju.das.jz@bp.renesas.com
Signed-off-by: Vinod Koul <vkoul@...>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...>
---
drivers/dma/sh/rz-dmac.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
index ee2872e7d64c..476847a4916b 100644
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -12,6 +12,7 @@
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
+#include <linux/iopoll.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of.h>
@@ -630,6 +631,21 @@ static void rz_dmac_virt_desc_free(struct virt_dma_desc *vd)
*/
}

+static void rz_dmac_device_synchronize(struct dma_chan *chan)
+{
+ struct rz_dmac_chan *channel = to_rz_dmac_chan(chan);
+ struct rz_dmac *dmac = to_rz_dmac(chan->device);
+ u32 chstat;
+ int ret;
+
+ ret = read_poll_timeout(rz_dmac_ch_readl, chstat, !(chstat & CHSTAT_EN),
+ 100, 100000, false, channel, CHSTAT, 1);
+ if (ret < 0)
+ dev_warn(dmac->dev, "DMA Timeout");
+
+ rz_dmac_set_dmars_register(dmac, channel->index, 0);
+}
+
/*
* -----------------------------------------------------------------------------
* IRQ handling
@@ -909,6 +925,7 @@ static int rz_dmac_probe(struct platform_device *pdev)
engine->device_config = rz_dmac_config;
engine->device_terminate_all = rz_dmac_terminate_all;
engine->device_issue_pending = rz_dmac_issue_pending;
+ engine->device_synchronize = rz_dmac_device_synchronize;

engine->copy_align = DMAENGINE_ALIGN_1_BYTE;
dma_set_max_seg_size(engine->dev, U32_MAX);
--
2.17.1