linux-kernel - Re: [PATCH v8 2/2] media: platform: Add Aspeed Video Engine driver

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Message-ID: <CACPK8XdQbq-9MbP7uMemyp0=Q+t1qnWNREdZRiyEcrART9vRig@mail.gmail.com>
Date:   Fri, 14 Dec 2018 11:39:14 +1030
From:   Joel Stanley <joel@....id.au>
To:     eajames@...ux.ibm.com
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Mark Rutland <mark.rutland@....com>,
        devicetree <devicetree@...r.kernel.org>,
        linux-aspeed@...ts.ozlabs.org, hverkuil@...all.nl,
        Rob Herring <robh+dt@...nel.org>, mchehab@...nel.org,
        linux-media@...r.kernel.org
Subject: Re: [PATCH v8 2/2] media: platform: Add Aspeed Video Engine driver

On Wed, 12 Dec 2018 at 04:09, Eddie James <eajames@...ux.ibm.com> wrote:
>
> The Video Engine (VE) embedded in the Aspeed AST2400 and AST2500 SOCs
> can capture and compress video data from digital or analog sources. With
> the Aspeed chip acting a service processor, the Video Engine can capture
> the host processor graphics output.

> +ASPEED VIDEO ENGINE DRIVER
> +M:     Eddie James <eajames@...ux.ibm.com>
> +L:     linux-media@...r.kernel.org
> +L:     openbmc@...ts.ozlabs.org (moderated for non-subscribers)

We tend to use the linux-aspeed list for upstream kernel discussions.
Up to you if you want to use the openbmc list though.

>  source "drivers/media/platform/omap/Kconfig"
>
> +config VIDEO_ASPEED
> +       tristate "Aspeed AST2400 and AST2500 Video Engine driver"
> +       depends on VIDEO_V4L2
> +       select VIDEOBUF2_DMA_CONTIG
> +       help
> +         Support for the Aspeed Video Engine (VE) embedded in the Aspeed
> +         AST2400 and AST2500 SOCs. The VE can capture and compress video data
> +         from digital or analog sources.

This might need updating in response to my questions below about
ast2400 testing.

> +++ b/drivers/media/platform/aspeed-video.c
> @@ -0,0 +1,1729 @@
> +// SPDX-License-Identifier: GPL-2.0+

You need to put this there as well:

// Copyright 2018 IBM Corp


> +static int aspeed_video_init(struct aspeed_video *video)
> +{
> +       int irq;
> +       int rc;
> +       struct device *dev = video->dev;
> +
> +       irq = irq_of_parse_and_map(dev->of_node, 0);
> +       if (!irq) {
> +               dev_err(dev, "Unable to find IRQ\n");
> +               return -ENODEV;
> +       }
> +
> +       rc = devm_request_irq(dev, irq, aspeed_video_irq, IRQF_SHARED,

The datasheet indicates this IRQ is for the video engline only, so I
don't think you want IRQF_SHARED.

> +                             DEVICE_NAME, video);
> +       if (rc < 0) {
> +               dev_err(dev, "Unable to request IRQ %d\n", irq);
> +               return rc;
> +       }
> +
> +       video->eclk = devm_clk_get(dev, "eclk");
> +       if (IS_ERR(video->eclk)) {
> +               dev_err(dev, "Unable to get ECLK\n");
> +               return PTR_ERR(video->eclk);
> +       }
> +
> +       video->vclk = devm_clk_get(dev, "vclk");
> +       if (IS_ERR(video->vclk)) {
> +               dev_err(dev, "Unable to get VCLK\n");
> +               return PTR_ERR(video->vclk);
> +       }
> +
> +       video->rst = devm_reset_control_get_exclusive(dev, NULL);
> +       if (IS_ERR(video->rst)) {
> +               dev_err(dev, "Unable to get VE reset\n");
> +               return PTR_ERR(video->rst);
> +       }

As discussed in the clock driver, this can go as you've already
released the reset when enabling the eclk.

However, you're requesting the clock without enabling it. You need to
do a clk_prepare_enable().

> +
> +       rc = of_reserved_mem_device_init(dev);
> +       if (rc) {
> +               dev_err(dev, "Unable to reserve memory\n");
> +               return rc;
> +       }
> +
> +       rc = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> +       if (rc) {
> +               dev_err(dev, "Failed to set DMA mask\n");
> +               of_reserved_mem_device_release(dev);
> +               return rc;
> +       }
> +
> +       if (!aspeed_video_alloc_buf(video, &video->jpeg,
> +                                   VE_JPEG_HEADER_SIZE)) {
> +               dev_err(dev, "Failed to allocate DMA for JPEG header\n");
> +               of_reserved_mem_device_release(dev);
> +               return rc;
> +       }
> +
> +       aspeed_video_init_jpeg_table(video->jpeg.virt, video->yuv420);
> +
> +       return 0;
> +}

> +
> +static const struct of_device_id aspeed_video_of_match[] = {
> +       { .compatible = "aspeed,ast2400-video-engine" },

I noticed the clock driver did not have the changed required for the
2400. Have you tested this on the ast2400?


> +       { .compatible = "aspeed,ast2500-video-engine" },
> +       {}
> +};
> +MODULE_DEVICE_TABLE(of, aspeed_video_of_match);
> +
> +static struct platform_driver aspeed_video_driver = {
> +       .driver = {
> +               .name = DEVICE_NAME,
> +               .of_match_table = aspeed_video_of_match,
> +       },
> +       .probe = aspeed_video_probe,
> +       .remove = aspeed_video_remove,
> +};