DMAC fixes

- Backport RCAR DMAC fixes from upstream
- Reeneable DMA for SCIF0 on R8A7797

1 files changed, 87 insertions, 0 deletions

diff --git a/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0080-dmaengine-rcar-dmac-ensure-CHCR-DE-bit-is-actually-0.patch b/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0080-dmaengine-rcar-dmac-ensure-CHCR-DE-bit-is-actually-0.patch
new file mode 100644
index 0000000..e1597ea
--- /dev/null
+++ b/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0080-dmaengine-rcar-dmac-ensure-CHCR-DE-bit-is-actually-0.patch
@@ -0,0 +1,87 @@
+From a8d46a7f5d17ca9cbe9e9c7d1d23dc6ea437e141 Mon Sep 17 00:00:00 2001
+From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
+Date: Fri, 17 Nov 2017 11:00:28 +0900
+Subject: [PATCH 1/2] dmaengine: rcar-dmac: ensure CHCR DE bit is actually 0
+ after clearing
+
+DMAC reads data from source device, and buffered it until transferable
+size for sink device. Because of this behavior, DMAC is including
+buffered data .
+
+Now, CHCR DE bit is controlling DMA transfer enable/disable.
+
+If DE bit was cleared during data transferring, or during buffering,
+it will flush buffered data if source device was peripheral device
+(The buffered data will be removed if source device was memory).
+Because of this behavior, driver should ensure that DE bit is actually
+0 after clearing.
+
+This patch adds new rcar_dmac_chcr_de_barrier() and call it after CHCR
+register access.
+
+Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
+Tested-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
+Tested-by: Ryo Kodama <ryo.kodama.vz@renesas.com>
+Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
+Signed-off-by: Vinod Koul <vinod.koul@intel.com>
+---
+ drivers/dma/sh/rcar-dmac.c | 22 ++++++++++++++++++++++
+ 1 file changed, 22 insertions(+)
+
+diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
+index 2b2c7db..c99fd0f 100644
+--- a/drivers/dma/sh/rcar-dmac.c
++++ b/drivers/dma/sh/rcar-dmac.c
+@@ -10,6 +10,7 @@
+  * published by the Free Software Foundation.
+  */
+ 
++#include <linux/delay.h>
+ #include <linux/dma-mapping.h>
+ #include <linux/dmaengine.h>
+ #include <linux/interrupt.h>
+@@ -741,6 +742,24 @@ static int rcar_dmac_fill_hwdesc(struct rcar_dmac_chan *chan,
+ /* -----------------------------------------------------------------------------
+  * Stop and reset
+  */
++static void rcar_dmac_chcr_de_barrier(struct rcar_dmac_chan *chan)
++{
++	u32 chcr;
++	unsigned int i;
++
++	/*
++	 * Ensure that the setting of the DE bit is actually 0 after
++	 * clearing it.
++	 */
++	for (i = 0; i < 1024; i++) {
++		chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
++		if (!(chcr & RCAR_DMACHCR_DE))
++			return;
++		udelay(1);
++	}
++
++	dev_err(chan->chan.device->dev, "CHCR DE check error\n");
++}
+ 
+ static void rcar_dmac_chan_halt(struct rcar_dmac_chan *chan)
+ {
+@@ -749,6 +768,7 @@ static void rcar_dmac_chan_halt(struct rcar_dmac_chan *chan)
+ 	chcr &= ~(RCAR_DMACHCR_DSE | RCAR_DMACHCR_DSIE | RCAR_DMACHCR_IE |
+ 		  RCAR_DMACHCR_TE | RCAR_DMACHCR_DE);
+ 	rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr);
++	rcar_dmac_chcr_de_barrier(chan);
+ }
+ 
+ static void rcar_dmac_chan_reinit(struct rcar_dmac_chan *chan)
+@@ -1481,6 +1501,8 @@ static irqreturn_t rcar_dmac_isr_channel(int irq, void *dev)
+ 	if (chcr & RCAR_DMACHCR_TE)
+ 		mask |= RCAR_DMACHCR_DE;
+ 	rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr & ~mask);
++	if (mask & RCAR_DMACHCR_DE)
++		rcar_dmac_chcr_de_barrier(chan);
+ 
+ 	if (chcr & RCAR_DMACHCR_DSE)
+ 		ret |= rcar_dmac_isr_desc_stage_end(chan);
+-- 
+1.9.1
+