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Date: Thu, 14 Jun 2018 14:04:25 +0530
From: Vinod Koul <vinod.koul@...aro.org>
To: Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
Cc: Geert Uytterhoeven <geert@...ux-m68k.org>,
Dan Williams <dan.j.williams@...el.com>,
Magnus Damm <magnus.damm@...il.com>,
Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Kieran Bingham <kieran@...uared.org.uk>,
Geert Uytterhoeven <geert+renesas@...der.be>,
dmaengine@...r.kernel.org,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@...r.kernel.org>
Subject: Re: [PATCH v2] dmaengine: rcar-dmac: don't use DMAC error interrupt
On 13-06-18, 08:49, Kuninori Morimoto wrote:
>
> From: Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
>
> 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.
So what happens when you are not in virtualization, multi OS..? Who
handles this interrupt?
>
> Signed-off-by: Magnus Damm <damm+renesas@...nsource.se>
> [Kuninori: updated patch to adjust DMACHCR/DMAOR]
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
> Tested-by: Nguyen Viet Dung <nv-dung@...so.co.jp>
> ---
> v1 -> v2
>
> - add [Kuninori: xxx] line on git log
> - don't remove DT property
> - tidyup rcar_dmac_isr_channel()
>
> .../devicetree/bindings/dma/renesas,rcar-dmac.txt | 1 +
> drivers/dma/sh/rcar-dmac.c | 72 +++++++---------------
> 2 files changed, 23 insertions(+), 50 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt b/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
> index b1ba6395..b8e1c13 100644
> --- a/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
> +++ b/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt
> @@ -38,6 +38,7 @@ Required Properties:
> - 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.
> + # "error" interrupt will be ignored, so far
>
> - clock-names: "fck" for the functional clock
> - clocks: a list of phandle + clock-specifier pairs, one for each entry
> diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
> index 2a2ccd9..279c930 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
> */
> @@ -1522,11 +1518,18 @@ 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_CAE) {
> + rcar_dmac_chan_halt(chan);
> + reinit = true;
> + goto spin_lock_end;
> + }
> +
> if (chcr & RCAR_DMACHCR_TE)
> mask |= RCAR_DMACHCR_DE;
> rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr & ~mask);
> @@ -1539,8 +1542,16 @@ static irqreturn_t rcar_dmac_isr_channel(int irq, void *dev)
> if (chcr & RCAR_DMACHCR_TE)
> ret |= rcar_dmac_isr_transfer_end(chan);
>
> +spin_lock_end:
> spin_unlock(&chan->lock);
>
> + if (reinit) {
> + dev_err(chan->chan.device->dev, "Channel Address Error\n");
> +
> + rcar_dmac_chan_reinit(chan);
> + ret = IRQ_HANDLED;
> + }
> +
> return ret;
> }
>
> @@ -1597,24 +1608,6 @@ 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 +1777,6 @@ 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 +1815,6 @@ 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 +1865,6 @@ 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 +1904,7 @@ 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[] = {
> --
> 1.9.1
--
~Vinod
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