Re: [PATCH v10 02/13] iommu/mediatek-v1: Free the existed fwspec if the master dev already has

On 28/01/2022 13:45, Mauro Carvalho Chehab wrote:

Em Fri, 28 Jan 2022 13:40:55 +0100
Mauro Carvalho Chehab [off-list ref] escreveu:

quoted

Hi Matthias/Yong,

Are you ok if this patch gets merged via the media tree together with the
remaining series, or do you prefer to apply it via SoC tree instead?

Same questions for other patches touching files outside drivers/media
on this pull request:

	https://patchwork.kernel.org/project/linux-mediatek/patch/7af52d61-47c7-581d-62ed-76a7f8315b16@xs4all.nl/

Looks good to me.

Please let me know once you accepted the pull request and I'll queue the DTS related changes from this series.

Regards,
Matthias

Like those:
	0004-0013-iommu-mediatek-v1-Free-the-existed-fwspec-if-the-mas.patch
	0005-0013-iommu-mediatek-Return-ENODEV-if-the-device-is-NULL.patch
	0006-0013-iommu-mediatek-Add-probe_defer-for-smi-larb.patch
	0007-0013-iommu-mediatek-Add-device_link-between-the-consumer-.patch

Regards,
Mauro

quoted

Regards,
Mauro


Em Mon, 17 Jan 2022 15:04:59 +0800
Yong Wu [off-list ref] escreveu:

quoted

When the iommu master device enters of_iommu_xlate, the ops may be
NULL(iommu dev is defered), then it will initialize the fwspec here:

[<c0c9c5bc>] (dev_iommu_fwspec_set) from [<c06bda80>]
(iommu_fwspec_init+0xbc/0xd4)
[<c06bd9c4>] (iommu_fwspec_init) from [<c06c0db4>]
(of_iommu_xlate+0x7c/0x12c)
[<c06c0d38>] (of_iommu_xlate) from [<c06c10e8>]
(of_iommu_configure+0x144/0x1e8)

BUT the mtk_iommu_v1.c only supports arm32, the probing flow still is a bit
weird. We always expect create the fwspec internally. otherwise it will
enter here and return fail.

static int mtk_iommu_create_mapping(struct device *dev,
				    struct of_phandle_args *args)
{
         ...
	if (!fwspec) {
	        ....
	} else if (dev_iommu_fwspec_get(dev)->ops != &mtk_iommu_ops) {
                 >>>>>>>>>>Enter here. return fail.<<<<<<<<<<<<
		return -EINVAL;
	}
	...
}

Thus, Free the existed fwspec if the master device already has fwspec.

This issue is reported at:
https://lore.kernel.org/linux-mediatek/trinity-7d9ebdc9-4849-4d93-bfb5-429dcb4ee449-1626253158870@3c-app-gmx-bs01/ (local)

Reported-by: Frank Wunderlich <redacted>
Tested-by: Frank Wunderlich <redacted> # BPI-R2/MT7623
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Acked-by: Joerg Roedel <redacted>
Acked-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
  drivers/iommu/mtk_iommu_v1.c | 9 +++++++++
  1 file changed, 9 insertions(+)

diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index be22fcf988ce..1467ba1e4417 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c

@@ -425,6 +425,15 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
  	struct mtk_iommu_data *data;
  	int err, idx = 0;
  
+	/*
+	 * In the deferred case, free the existed fwspec.
+	 * Always initialize the fwspec internally.
+	 */
+	if (fwspec) {
+		iommu_fwspec_free(dev);
+		fwspec = dev_iommu_fwspec_get(dev);
+	}
+
  	while (!of_parse_phandle_with_args(dev->of_node, "iommus",
  					   "#iommu-cells",
  					   idx, &iommu_spec)) {

Thanks,
Mauro

Thanks,
Mauro

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