Re: [PATCH 5/9] [media] s5p-jpeg: Add IOMMU support

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On 06/02/2017 06:02 PM, Thierry Escande wrote:
From: Tony K Nadackal <tony.kn@xxxxxxxxxxx>

This patch adds support for IOMMU s5p-jpeg driver if the Exynos IOMMU
and ARM DMA IOMMU configurations are supported. The address space is
created with size limited to 256M and base address set to 0x20000000.

I don't think this patch is needed now, a few things changed in mainline
since v3.8. The mapping is being created automatically now for this single
JPEG CODEC device by the driver core/dma-mapping code AFAICS.
See dma_configure() in drivers/base/dd.c.
I doubt we need a specific CPU address range, but even if we would shouldn't
it be specified through the dma-ranges DT property?

Signed-off-by: Tony K Nadackal <tony.kn@xxxxxxxxxxx>
Signed-off-by: Thierry Escande <thierry.escande@xxxxxxxxxxxxx>
---
  drivers/media/platform/s5p-jpeg/jpeg-core.c | 77 +++++++++++++++++++++++++++++
  1 file changed, 77 insertions(+)

+#if defined(CONFIG_EXYNOS_IOMMU) && defined(CONFIG_ARM_DMA_USE_IOMMU)
+static int jpeg_iommu_init(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int err;
+
+	mapping = arm_iommu_create_mapping(&platform_bus_type, 0x20000000,
+					   SZ_512M);
+	if (IS_ERR(mapping)) {
+		dev_err(dev, "IOMMU mapping failed\n");
+		return PTR_ERR(mapping);
+	}
+
+	dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms), GFP_KERNEL);

dev->dma_parms seems to be unused.

+	if (!dev->dma_parms) {
+		err = -ENOMEM;
+		goto error_alloc;
+	}
+
+	err = dma_set_max_seg_size(dev, 0xffffffffu);
+	if (err)
+		goto error;
+
+	err = arm_iommu_attach_device(dev, mapping);
+	if (err)
+		goto error;
+
+	return 0;
+
+error:
+	devm_kfree(dev, dev->dma_parms);

There is no need for this devm_kfree() call.

+	dev->dma_parms = NULL;
+
+error_alloc:
+	arm_iommu_release_mapping(mapping);
+	mapping = NULL;
+
+	return err;
+}
+
+static void jpeg_iommu_deinit(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+
+	if (mapping) {
+		arm_iommu_detach_device(dev);
+		devm_kfree(dev, dev->dma_parms);

Ditto.

+		dev->dma_parms = NULL;
+		arm_iommu_release_mapping(mapping);
+		mapping = NULL;
+	}
+}

  /*
   * ============================================================================
   * Device file operations
@@ -2816,6 +2882,13 @@ static int s5p_jpeg_probe(struct platform_device *pdev)

+	ret = jpeg_iommu_init(pdev);

@@ -2962,6 +3035,10 @@ static int s5p_jpeg_remove(struct platform_device *pdev)

+	jpeg_iommu_deinit(pdev);

  	return 0;
  }

--
Thanks,
Sylwester



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