On Fri, Apr 02, 2021 at 06:05:36PM +0900, Hector Martin wrote:
> This implements the 'nonposted-mmio' boolean property. Placing this
> property in a bus marks all direct child devices as requiring
> non-posted MMIO mappings. If no such property is found, the default
> is posted MMIO.
>
> of_mmio_is_nonposted() performs this check to determine if a given
> device has requested non-posted MMIO.
>
> of_address_to_resource() uses this to set the IORESOURCE_MEM_NONPOSTED
> flag on resources that require non-posted MMIO.
>
> of_iomap() and of_io_request_and_map() then use this flag to pick the
> correct ioremap() variant.
>
> This mechanism is currently restricted to builds that support Apple ARM
> platforms, as an optimization.
>
> Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> Signed-off-by: Hector Martin <marcan@xxxxxxxxx>
> ---
> drivers/of/address.c | 43 ++++++++++++++++++++++++++++++++++++--
> include/linux/of_address.h | 1 +
> 2 files changed, 42 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index 73ddf2540f3f..6485cc536e81 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -847,6 +847,9 @@ static int __of_address_to_resource(struct device_node *dev,
> return -EINVAL;
> memset(r, 0, sizeof(struct resource));
>
> + if (of_mmio_is_nonposted(dev))
> + flags |= IORESOURCE_MEM_NONPOSTED;
> +
> r->start = taddr;
> r->end = taddr + size - 1;
> r->flags = flags;
> @@ -896,7 +899,10 @@ void __iomem *of_iomap(struct device_node *np, int index)
> if (of_address_to_resource(np, index, &res))
> return NULL;
>
> - return ioremap(res.start, resource_size(&res));
> + if (res.flags & IORESOURCE_MEM_NONPOSTED)
> + return ioremap_np(res.start, resource_size(&res));
> + else
> + return ioremap(res.start, resource_size(&res));
> }
> EXPORT_SYMBOL(of_iomap);
>
> @@ -928,7 +934,11 @@ void __iomem *of_io_request_and_map(struct device_node *np, int index,
> if (!request_mem_region(res.start, resource_size(&res), name))
> return IOMEM_ERR_PTR(-EBUSY);
>
> - mem = ioremap(res.start, resource_size(&res));
> + if (res.flags & IORESOURCE_MEM_NONPOSTED)
> + mem = ioremap_np(res.start, resource_size(&res));
> + else
> + mem = ioremap(res.start, resource_size(&res));
> +
> if (!mem) {
> release_mem_region(res.start, resource_size(&res));
> return IOMEM_ERR_PTR(-ENOMEM);
> @@ -1094,3 +1104,32 @@ bool of_dma_is_coherent(struct device_node *np)
> return false;
> }
> EXPORT_SYMBOL_GPL(of_dma_is_coherent);
> +
> +/**
> + * of_mmio_is_nonposted - Check if device uses non-posted MMIO
> + * @np: device node
> + *
> + * Returns true if the "nonposted-mmio" property was found for
> + * the device's bus.
> + *
> + * This is currently only enabled on builds that support Apple ARM devices, as
> + * an optimization.
> + */
> +bool of_mmio_is_nonposted(struct device_node *np)
> +{
> + struct device_node *parent;
> + bool nonposted;
> +
> + if (!IS_ENABLED(CONFIG_ARCH_APPLE))
> + return false;
> +
> + parent = of_get_parent(np);
> + if (!parent)
> + return false;
> +
> + nonposted = of_property_read_bool(parent, "nonposted-mmio");
> +
> + of_node_put(parent);
> + return nonposted;
> +}
> +EXPORT_SYMBOL_GPL(of_mmio_is_nonposted);
Is this needed outside of of/address.c? If not, please make it static
and don't export.
With that,
Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
