dmaengine: rcar-dmac: don't use DMAC error interrupt

Commit Message

Kuninori Morimoto June 12, 2018, 7:40 a.m. UTC

From: Kuninori Morimoto <[e-mail]>

Current rcar-dmac is using DMAC error interrupt which will handle all
channel's error. But in this design, error handling itself will be
issue if user want to use virtualization, multi OS, etc.
This patch removes current DMAC error interrupt handling, and handle it
on each channel interrupt handler.

Signed-off-by: Magnus Damm <[e-mail]>
Signed-off-by: Kuninori Morimoto <[e-mail]>
Tested-by: Nguyen Viet Dung <[e-mail]>
---
 .../devicetree/bindings/dma/renesas,rcar-dmac.txt  | 17 ++---
 drivers/dma/sh/rcar-dmac.c                         | 89 +++++++---------------
 2 files changed, 35 insertions(+), 71 deletions(-)

Comments

Geert Uytterhoeven June 12, 2018, 7:59 a.m. UTC | #1

Hi Morimoto-san,

CC devicetree

Thanks for your patch!

On Tue, Jun 12, 2018 at 9:40 AM Kuninori Morimoto
<[e-mail]> wrote:
> From: Kuninori Morimoto <[e-mail]>
>
> Current rcar-dmac is using DMAC error interrupt which will handle all
> channel's error. But in this design, error handling itself will be
> issue if user want to use virtualization, multi OS, etc.
> This patch removes current DMAC error interrupt handling, and handle it
> on each channel interrupt handler.
>
> Signed-off-by: Magnus Damm <[e-mail]>
> Signed-off-by: Kuninori Morimoto <[e-mail]>

Who wrote this patch, you or Magnus? Or is this a joint effort?

> --- a/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
> +++ b/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
> @@ -35,9 +35,8 @@ Required Properties:
>
>  - interrupts: interrupt specifiers for the DMAC, one for each entry in
>    interrupt-names.
> -- interrupt-names: one entry for the error interrupt, named "error", plus one
> -  entry per channel, named "ch%u", where %u is the channel number ranging from
> -  zero to the number of channels minus one.
> +- interrupt-names: one entry per channel, named "ch%u", where %u is the
> +  channel number ranging from zero to the number of channels minus one.

DT bindings describe hardware, not software policy.
So IMHO the error interrupt must not be removed from the bindings (and
from the DTS and example).

> --- a/drivers/dma/sh/rcar-dmac.c
> +++ b/drivers/dma/sh/rcar-dmac.c
> @@ -1522,25 +1518,37 @@ static irqreturn_t rcar_dmac_isr_channel(int irq, void *dev)

[...]

>
> +       if (reinit) {
> +               dev_err(chan->chan.device->dev, "Channel Address Error happen\n");

s/happen/happened/, or just drop the word (reducing kernel size ;-)

The rest looks good to me (but I haven't tested it), so with the above fixed:
Reviewed-by: Geert Uytterhoeven <[e-mail]>

Gr{oetje,eeting}s,

                        Geert

Kuninori Morimoto June 12, 2018, 8:12 a.m. UTC | #2

Hi Geert

Thank you for your light speed review :)

> > From: Kuninori Morimoto <[e-mail]>
> >
> > Current rcar-dmac is using DMAC error interrupt which will handle all
> > channel's error. But in this design, error handling itself will be
> > issue if user want to use virtualization, multi OS, etc.
> > This patch removes current DMAC error interrupt handling, and handle it
> > on each channel interrupt handler.
> >
> > Signed-off-by: Magnus Damm <[e-mail]>
> > Signed-off-by: Kuninori Morimoto <[e-mail]>
> 
> Who wrote this patch, you or Magnus? Or is this a joint effort?

Original was Magnus, and I updated it.
I think I need to add such things.

> > --- a/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
> > +++ b/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
> > @@ -35,9 +35,8 @@ Required Properties:
> >
> >  - interrupts: interrupt specifiers for the DMAC, one for each entry in
> >    interrupt-names.
> > -- interrupt-names: one entry for the error interrupt, named "error", plus one
> > -  entry per channel, named "ch%u", where %u is the channel number ranging from
> > -  zero to the number of channels minus one.
> > +- interrupt-names: one entry per channel, named "ch%u", where %u is the
> > +  channel number ranging from zero to the number of channels minus one.
> 
> DT bindings describe hardware, not software policy.
> So IMHO the error interrupt must not be removed from the bindings (and
> from the DTS and example).

IC

> The rest looks good to me (but I haven't tested it), so with the above fixed:
> Reviewed-by: Geert Uytterhoeven <[e-mail]>

Thanks. Will post v2 tomorrow

Best regards
---
Kuninori Morimoto

Patch

diff --git a/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt b/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
index b1ba6395..416caf0 100644
--- a/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
+++ b/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
@@ -35,9 +35,8 @@  Required Properties:
 
 - interrupts: interrupt specifiers for the DMAC, one for each entry in
   interrupt-names.
-- interrupt-names: one entry for the error interrupt, named "error", plus one
-  entry per channel, named "ch%u", where %u is the channel number ranging from
-  zero to the number of channels minus one.
+- interrupt-names: one entry per channel, named "ch%u", where %u is the
+  channel number ranging from zero to the number of channels minus one.
 
 - clock-names: "fck" for the functional clock
 - clocks: a list of phandle + clock-specifier pairs, one for each entry
@@ -53,8 +52,7 @@  Example: R8A7790 (R-Car H2) SYS-DMACs
 	dmac0: dma-controller@e6700000 {
 		compatible = "renesas,dmac-r8a7790", "renesas,rcar-dmac";
 		reg = <0 0xe6700000 0 0x20000>;
-		interrupts = <0 197 IRQ_TYPE_LEVEL_HIGH
-			      0 200 IRQ_TYPE_LEVEL_HIGH
+		interrupts = <0 200 IRQ_TYPE_LEVEL_HIGH
 			      0 201 IRQ_TYPE_LEVEL_HIGH
 			      0 202 IRQ_TYPE_LEVEL_HIGH
 			      0 203 IRQ_TYPE_LEVEL_HIGH
@@ -69,8 +67,7 @@  Example: R8A7790 (R-Car H2) SYS-DMACs
 			      0 212 IRQ_TYPE_LEVEL_HIGH
 			      0 213 IRQ_TYPE_LEVEL_HIGH
 			      0 214 IRQ_TYPE_LEVEL_HIGH>;
-		interrupt-names = "error",
-				"ch0", "ch1", "ch2", "ch3",
+		interrupt-names = "ch0", "ch1", "ch2", "ch3",
 				"ch4", "ch5", "ch6", "ch7",
 				"ch8", "ch9", "ch10", "ch11",
 				"ch12", "ch13", "ch14";
@@ -83,8 +80,7 @@  Example: R8A7790 (R-Car H2) SYS-DMACs
 	dmac1: dma-controller@e6720000 {
 		compatible = "renesas,dmac-r8a7790", "renesas,rcar-dmac";
 		reg = <0 0xe6720000 0 0x20000>;
-		interrupts = <0 220 IRQ_TYPE_LEVEL_HIGH
-			      0 216 IRQ_TYPE_LEVEL_HIGH
+		interrupts = <0 216 IRQ_TYPE_LEVEL_HIGH
 			      0 217 IRQ_TYPE_LEVEL_HIGH
 			      0 218 IRQ_TYPE_LEVEL_HIGH
 			      0 219 IRQ_TYPE_LEVEL_HIGH
@@ -99,8 +95,7 @@  Example: R8A7790 (R-Car H2) SYS-DMACs
 			      0 316 IRQ_TYPE_LEVEL_HIGH
 			      0 317 IRQ_TYPE_LEVEL_HIGH
 			      0 318 IRQ_TYPE_LEVEL_HIGH>;
-		interrupt-names = "error",
-				"ch0", "ch1", "ch2", "ch3",
+		interrupt-names = "ch0", "ch1", "ch2", "ch3",
 				"ch4", "ch5", "ch6", "ch7",
 				"ch8", "ch9", "ch10", "ch11",
 				"ch12", "ch13", "ch14";
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 2a2ccd9..c406c56 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -431,7 +431,8 @@  static void rcar_dmac_chan_start_xfer(struct rcar_dmac_chan *chan)
 		chcr |= RCAR_DMACHCR_DPM_DISABLED | RCAR_DMACHCR_IE;
 	}
 
-	rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr | RCAR_DMACHCR_DE);
+	rcar_dmac_chan_write(chan, RCAR_DMACHCR,
+			     chcr | RCAR_DMACHCR_DE | RCAR_DMACHCR_CAIE);
 }
 
 static int rcar_dmac_init(struct rcar_dmac *dmac)
@@ -783,7 +784,8 @@  static void rcar_dmac_chan_halt(struct rcar_dmac_chan *chan)
 	u32 chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
 
 	chcr &= ~(RCAR_DMACHCR_DSE | RCAR_DMACHCR_DSIE | RCAR_DMACHCR_IE |
-		  RCAR_DMACHCR_TE | RCAR_DMACHCR_DE);
+		  RCAR_DMACHCR_TE | RCAR_DMACHCR_DE |
+		  RCAR_DMACHCR_CAE | RCAR_DMACHCR_CAIE);
 	rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr);
 	rcar_dmac_chcr_de_barrier(chan);
 }
@@ -812,12 +814,7 @@  static void rcar_dmac_chan_reinit(struct rcar_dmac_chan *chan)
 	}
 }
 
-static void rcar_dmac_stop(struct rcar_dmac *dmac)
-{
-	rcar_dmac_write(dmac, RCAR_DMAOR, 0);
-}
-
-static void rcar_dmac_abort(struct rcar_dmac *dmac)
+static void rcar_dmac_stop_all_chan(struct rcar_dmac *dmac)
 {
 	unsigned int i;
 
@@ -829,11 +826,10 @@  static void rcar_dmac_abort(struct rcar_dmac *dmac)
 		spin_lock(&chan->lock);
 		rcar_dmac_chan_halt(chan);
 		spin_unlock(&chan->lock);
-
-		rcar_dmac_chan_reinit(chan);
 	}
 }
 
+
 /* -----------------------------------------------------------------------------
  * Descriptors preparation
  */
@@ -1522,25 +1518,37 @@  static irqreturn_t rcar_dmac_isr_channel(int irq, void *dev)
 	u32 mask = RCAR_DMACHCR_DSE | RCAR_DMACHCR_TE;
 	struct rcar_dmac_chan *chan = dev;
 	irqreturn_t ret = IRQ_NONE;
+	bool reinit = false;
 	u32 chcr;
 
 	spin_lock(&chan->lock);
 
 	chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR);
-	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);
+	if (chcr & RCAR_DMACHCR_CAE) {
+		rcar_dmac_chan_halt(chan);
+		reinit = true;
+	} else {
+		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_TE)
-		ret |= rcar_dmac_isr_transfer_end(chan);
+		if (chcr & RCAR_DMACHCR_DSE)
+			ret |= rcar_dmac_isr_desc_stage_end(chan);
 
+		if (chcr & RCAR_DMACHCR_TE)
+			ret |= rcar_dmac_isr_transfer_end(chan);
+	}
 	spin_unlock(&chan->lock);
 
+	if (reinit) {
+		dev_err(chan->chan.device->dev, "Channel Address Error happen\n");
+
+		rcar_dmac_chan_reinit(chan);
+		ret = IRQ_HANDLED;
+	}
+
 	return ret;
 }
 
@@ -1597,24 +1605,6 @@  static irqreturn_t rcar_dmac_isr_channel_thread(int irq, void *dev)
 	return IRQ_HANDLED;
 }
 
-static irqreturn_t rcar_dmac_isr_error(int irq, void *data)
-{
-	struct rcar_dmac *dmac = data;
-
-	if (!(rcar_dmac_read(dmac, RCAR_DMAOR) & RCAR_DMAOR_AE))
-		return IRQ_NONE;
-
-	/*
-	 * An unrecoverable error occurred on an unknown channel. Halt the DMAC,
-	 * abort transfers on all channels, and reinitialize the DMAC.
-	 */
-	rcar_dmac_stop(dmac);
-	rcar_dmac_abort(dmac);
-	rcar_dmac_init(dmac);
-
-	return IRQ_HANDLED;
-}
-
 /* -----------------------------------------------------------------------------
  * OF xlate and channel filter
  */
@@ -1784,8 +1774,6 @@  static int rcar_dmac_probe(struct platform_device *pdev)
 	struct rcar_dmac *dmac;
 	struct resource *mem;
 	unsigned int i;
-	char *irqname;
-	int irq;
 	int ret;
 
 	dmac = devm_kzalloc(&pdev->dev, sizeof(*dmac), GFP_KERNEL);
@@ -1824,17 +1812,6 @@  static int rcar_dmac_probe(struct platform_device *pdev)
 	if (IS_ERR(dmac->iomem))
 		return PTR_ERR(dmac->iomem);
 
-	irq = platform_get_irq_byname(pdev, "error");
-	if (irq < 0) {
-		dev_err(&pdev->dev, "no error IRQ specified\n");
-		return -ENODEV;
-	}
-
-	irqname = devm_kasprintf(dmac->dev, GFP_KERNEL, "%s:error",
-				 dev_name(dmac->dev));
-	if (!irqname)
-		return -ENOMEM;
-
 	/* Enable runtime PM and initialize the device. */
 	pm_runtime_enable(&pdev->dev);
 	ret = pm_runtime_get_sync(&pdev->dev);
@@ -1885,14 +1862,6 @@  static int rcar_dmac_probe(struct platform_device *pdev)
 			goto error;
 	}
 
-	ret = devm_request_irq(&pdev->dev, irq, rcar_dmac_isr_error, 0,
-			       irqname, dmac);
-	if (ret) {
-		dev_err(&pdev->dev, "failed to request IRQ %u (%d)\n",
-			irq, ret);
-		return ret;
-	}
-
 	/* Register the DMAC as a DMA provider for DT. */
 	ret = of_dma_controller_register(pdev->dev.of_node, rcar_dmac_of_xlate,
 					 NULL);
@@ -1932,7 +1901,7 @@  static void rcar_dmac_shutdown(struct platform_device *pdev)
 {
 	struct rcar_dmac *dmac = platform_get_drvdata(pdev);
 
-	rcar_dmac_stop(dmac);
+	rcar_dmac_stop_all_chan(dmac);
 }
 
 static const struct of_device_id rcar_dmac_of_ids[] = {