On Thu, Aug 5, 2021 at 3:47 AM Will Deacon <w...@kernel.org> wrote:
>
> If CONFIG_DMA_RESTRICTED_POOL=n then probing a device with a reference
> to a "restricted-dma-pool" will fail with a reasonably cryptic error:
I'm left wondering why of_dma_set_restricted_buffer() is even enabled
with CONFIG_DMA_RESTRICTED_POOL=n.
of_dma_set_restricted_buffer() should use IS_ENABLED and it should
also be moved to of/device.c. There's no reason for it to be in
of/address.c. It has nothing to do with address parsing.
> | pci-host-generic: probe of 10000.pci failed with error -22
>
> Print a more helpful message in this case and try to continue probing
> the device as we do if the kernel doesn't have the restricted DMA patches
> applied or either CONFIG_OF_ADDRESS or CONFIG_HAS_DMA =n.
I think you'd have to work pretty hard to hit this code path with
either of the above config options off.
> Cc: Claire Chang <tien...@chromium.org>
> Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
> Cc: Robin Murphy <robin.mur...@arm.com>
> Cc: Christoph Hellwig <h...@lst.de>
> Cc: Rob Herring <robh...@kernel.org>
> Signed-off-by: Will Deacon <w...@kernel.org>
> ---
> drivers/of/address.c | 8 ++++----
> drivers/of/device.c | 2 +-
> drivers/of/of_private.h | 8 +++-----
> 3 files changed, 8 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index 973257434398..f6bf4b423c2a 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -997,7 +997,7 @@ int of_dma_get_range(struct device_node *np, const struct
> bus_dma_region **map)
> return ret;
> }
>
> -int of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
> +void of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
> {
> struct device_node *node, *of_node = dev->of_node;
> int count, i;
> @@ -1022,11 +1022,11 @@ int of_dma_set_restricted_buffer(struct device *dev,
> struct device_node *np)
> */
> if (of_device_is_compatible(node, "restricted-dma-pool") &&
> of_device_is_available(node))
> - return of_reserved_mem_device_init_by_idx(dev,
> of_node,
> - i);
> + break;
> }
>
> - return 0;
> + if (i != count && of_reserved_mem_device_init_by_idx(dev, of_node, i))
> + dev_warn(dev, "failed to initialise \"restricted-dma-pool\"
> memory node\n");
> }
> #endif /* CONFIG_HAS_DMA */
>
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index 2defdca418ec..258a2b099410 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -166,7 +166,7 @@ int of_dma_configure_id(struct device *dev, struct
> device_node *np,
> arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);
>
> if (!iommu)
> - return of_dma_set_restricted_buffer(dev, np);
> + of_dma_set_restricted_buffer(dev, np);
>
> return 0;
> }
> diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
> index f557bd22b0cf..bc883f69496b 100644
> --- a/drivers/of/of_private.h
> +++ b/drivers/of/of_private.h
> @@ -163,18 +163,16 @@ struct bus_dma_region;
> #if defined(CONFIG_OF_ADDRESS) && defined(CONFIG_HAS_DMA)
> int of_dma_get_range(struct device_node *np,
> const struct bus_dma_region **map);
> -int of_dma_set_restricted_buffer(struct device *dev, struct device_node *np);
> +void of_dma_set_restricted_buffer(struct device *dev, struct device_node
> *np);
> #else
> static inline int of_dma_get_range(struct device_node *np,
> const struct bus_dma_region **map)
> {
> return -ENODEV;
> }
> -static inline int of_dma_set_restricted_buffer(struct device *dev,
> - struct device_node *np)
> +static inline void of_dma_set_restricted_buffer(struct device *dev,
> + struct device_node *np)
> {
> - /* Do nothing, successfully. */
> - return 0;
> }
> #endif
>
> --
> 2.32.0.605.g8dce9f2422-goog
>
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