Re: [PATCH v2] of/device: Update dma_range_map only when dev has valid dma-ranges

On 2021-01-27 19:07, Rob Herring wrote:

On Tue, Jan 19, 2021 at 4:52 AM Yong Wu [off-list ref] wrote:

quoted

The commit e0d072782c73 ("dma-mapping: introduce DMA range map,
supplanting dma_pfn_offset") always update dma_range_map even though it was
already set, like in the sunxi_mbus driver. the issue is reported at [1].
This patch avoid this(Updating it only when dev has valid dma-ranges).

only when dev *doesn't* have valid dma-ranges?

I believe the intent is to mean when a valid "dma-ranges" property is 
specified in DT. The implementation allows DT to take precedence even if 
platform code *has* already installed a dma_range_map, although we 
shouldn't expect that to ever happen (except perhaps in the wild early 
days of platform bringup).

Robin.

quoted

Meanwhile, dma_range_map contains the devices' dma_ranges information,
This patch moves dma_range_map before of_iommu_configure. The iommu
driver may need to know the dma_address requirements of its iommu
consumer devices.

[1] https://lore.kernel.org/linux-arm-kernel/5c7946f3-b56e-da00-a750-be097c7ceb32@arm.com/ (local)

CC: Rob Herring <robh+dt@kernel.org>
CC: Frank Rowand <redacted>
Fixes: e0d072782c73 ("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset"),
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Signed-off-by: Paul Kocialkowski <redacted>
Reviewed-by: Rob Herring <robh@kernel.org>
---
  drivers/of/device.c | 10 +++++++---
  1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/of/device.c b/drivers/of/device.c
index aedfaaafd3e7..1122daa8e273 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c

@@ -162,9 +162,11 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
         mask = DMA_BIT_MASK(ilog2(end) + 1);
         dev->coherent_dma_mask &= mask;
         *dev->dma_mask &= mask;
-       /* ...but only set bus limit if we found valid dma-ranges earlier */
-       if (!ret)
+       /* ...but only set bus limit and range map if we found valid dma-ranges earlier */
+       if (!ret) {
                 dev->bus_dma_limit = end;
+               dev->dma_range_map = map;
+       }

         coherent = of_dma_is_coherent(np);
         dev_dbg(dev, "device is%sdma coherent\n",

@@ -172,6 +174,9 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,

         iommu = of_iommu_configure(dev, np, id);
         if (PTR_ERR(iommu) == -EPROBE_DEFER) {
+               /* Don't touch range map if it wasn't set from a valid dma-ranges */
+               if (!ret)
+                       dev->dma_range_map = NULL;
                 kfree(map);
                 return -EPROBE_DEFER;
         }

@@ -181,7 +186,6 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,

         arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);

-       dev->dma_range_map = map;
         return 0;
  }
  EXPORT_SYMBOL_GPL(of_dma_configure_id);
--

2.18.0

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel