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Message-ID: <b0218fe4-d2e8-40ab-88e8-5f44ec4ce8da@denx.de>
Date: Fri, 18 Jun 2021 07:54:35 +0200
From: Stefan Roese <sr@...x.de>
To: Olivier Dautricourt <olivier.dautricourt@...lia.com>,
Rob Herring <robh+dt@...nel.org>, Vinod Koul <vkoul@...nel.org>
Cc: dmaengine@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] dmaengine: altera-msgdma: make response port optional
On 17.06.21 21:53, Olivier Dautricourt wrote:
> The response slave port can be disabled in some configuration [1] and
> csr + MSGDMA_CSR_RESP_FILL_LEVEL will be 0 even if transfer has suceeded.
> We have to only rely on the interrupts in that scenario.
> This was tested on cyclone V with the controller resp port disabled.
>
> [1] https://www.intel.com/content/www/us/en/programmable/documentation/sfo1400787952932.html
> 30.3.1.2
> 30.3.1.3
> 30.5.5
>
> Fixes:
> https://forum.rocketboards.org/t/ip-msgdma-linux-driver/1919
> Signed-off-by: Olivier Dautricourt <olivier.dautricourt@...lia.com>
Reviewed-by: Stefan Roese <sr@...x.de>
Thanks,
Stefan
> ---
> drivers/dma/altera-msgdma.c | 37 ++++++++++++++++++++++++++-----------
> 1 file changed, 26 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/dma/altera-msgdma.c b/drivers/dma/altera-msgdma.c
> index 0fe0676f8e1d..5a2c7573b692 100644
> --- a/drivers/dma/altera-msgdma.c
> +++ b/drivers/dma/altera-msgdma.c
> @@ -691,10 +691,14 @@ static void msgdma_tasklet(struct tasklet_struct *t)
>
> spin_lock_irqsave(&mdev->lock, flags);
>
> - /* Read number of responses that are available */
> - count = ioread32(mdev->csr + MSGDMA_CSR_RESP_FILL_LEVEL);
> - dev_dbg(mdev->dev, "%s (%d): response count=%d\n",
> - __func__, __LINE__, count);
> + if (mdev->resp) {
> + /* Read number of responses that are available */
> + count = ioread32(mdev->csr + MSGDMA_CSR_RESP_FILL_LEVEL);
> + dev_dbg(mdev->dev, "%s (%d): response count=%d\n",
> + __func__, __LINE__, count);
> + } else {
> + count = 1;
> + }
>
> while (count--) {
> /*
> @@ -703,8 +707,12 @@ static void msgdma_tasklet(struct tasklet_struct *t)
> * have any real values, like transferred bytes or error
> * bits. So we need to just drop these values.
> */
> - size = ioread32(mdev->resp + MSGDMA_RESP_BYTES_TRANSFERRED);
> - status = ioread32(mdev->resp + MSGDMA_RESP_STATUS);
> + if (mdev->resp) {
> + size = ioread32(mdev->resp +
> + MSGDMA_RESP_BYTES_TRANSFERRED);
> + status = ioread32(mdev->resp +
> + MSGDMA_RESP_STATUS);
> + }
>
> msgdma_complete_descriptor(mdev);
> msgdma_chan_desc_cleanup(mdev);
> @@ -757,14 +765,21 @@ static void msgdma_dev_remove(struct msgdma_device *mdev)
> }
>
> static int request_and_map(struct platform_device *pdev, const char *name,
> - struct resource **res, void __iomem **ptr)
> + struct resource **res, void __iomem **ptr,
> + bool optional)
> {
> struct resource *region;
> struct device *device = &pdev->dev;
>
> *res = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
> if (*res == NULL) {
> - dev_err(device, "resource %s not defined\n", name);
> + if (optional) {
> + *ptr = NULL;
> + dev_info(device, "optional resource %s not defined\n",
> + name);
> + return 0;
> + }
> + dev_err(device, "mandatory resource %s not defined\n", name);
> return -ENODEV;
> }
>
> @@ -805,17 +820,17 @@ static int msgdma_probe(struct platform_device *pdev)
> mdev->dev = &pdev->dev;
>
> /* Map CSR space */
> - ret = request_and_map(pdev, "csr", &dma_res, &mdev->csr);
> + ret = request_and_map(pdev, "csr", &dma_res, &mdev->csr, false);
> if (ret)
> return ret;
>
> /* Map (extended) descriptor space */
> - ret = request_and_map(pdev, "desc", &dma_res, &mdev->desc);
> + ret = request_and_map(pdev, "desc", &dma_res, &mdev->desc, false);
> if (ret)
> return ret;
>
> /* Map response space */
> - ret = request_and_map(pdev, "resp", &dma_res, &mdev->resp);
> + ret = request_and_map(pdev, "resp", &dma_res, &mdev->resp, true);
> if (ret)
> return ret;
>
> --
> 2.31.0.rc2
>
Viele Grüße,
Stefan
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Phone: (+49)-8142-66989-51 Fax: (+49)-8142-66989-80 Email: sr@...x.de
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