[v3,3/7] of: address: Add parent pointer to the __of_translate_address args

The __of_translate_address function is used to translate the device tree
addresses to physical addresses using the various ranges property to create
the offset.

However, it's shared between the CPU addresses (based on the ranges
property) and the DMA addresses (based on dma-ranges). Since we're going to
add support for a DMA parent node that is not the DT parent node, we need
to change the logic a bit to have an optional parent node that we should
use.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
---
 drivers/of/address.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

On 11/02/2019 15:02, Maxime Ripard wrote:
> The __of_translate_address function is used to translate the device tree
> addresses to physical addresses using the various ranges property to create
> the offset.
> 
> However, it's shared between the CPU addresses (based on the ranges
> property) and the DMA addresses (based on dma-ranges). Since we're going to
> add support for a DMA parent node that is not the DT parent node, we need
> to change the logic a bit to have an optional parent node that we should
> use.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> ---
>   drivers/of/address.c | 21 ++++++++++++---------
>   1 file changed, 12 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index 2270373b30ab..4c5dc21c71ca 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -569,10 +569,10 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus,
>    * relative to that node.
>    */
>   static u64 __of_translate_address(struct device_node *dev,
> +				  struct device_node *parent,
>   				  const __be32 *in_addr, const char *rprop,
>   				  struct device_node **host)
>   {
> -	struct device_node *parent = NULL;
>   	struct of_bus *bus, *pbus;
>   	__be32 addr[OF_MAX_ADDR_CELLS];
>   	int na, ns, pna, pns;
> @@ -583,11 +583,14 @@ static u64 __of_translate_address(struct device_node *dev,
>   	/* Increase refcount at current level */
>   	of_node_get(dev);
>   
> -	*host = NULL;
> -	/* Get parent & match bus type */
> -	parent = of_get_parent(dev);
> -	if (parent == NULL)
> -		goto bail;
> +	if (!parent) {

I would have suggested having the callers make the of_get_parent() call 
themselves, but having pulled up the code for a look at the whole 
function, there's a bigger issue at play. The parent traversal happens 
within the main translation loop as well, and topologies could quite 
feasibly exist where that makes a difference, e.g.:

	icc {
		#interconnect-cells = <0>;
		dma-ranges = <...>;
	};

	subsystem {
		interconnects = <&icc>;
		interconnect-names = "dma";

		intermediate-bus {
			dma-ranges;

			device {
				...
			};
		};
	};

or:

	icc2 {
		#interconnect-cells = <0>;
		dma-ranges = <...>;
	};

	icc1 {
		#interconnect-cells = <0>;
		dma-ranges = <...>;
		interconnects = <&icc2>;
		interconnect-names = "dma";
	};

	device {
		interconnects = <&icc1>;
		interconnect-names = "dma";
		...
	};

So I guess the answer is to switch this over to using a callback and 
have the callers pass of_get_parent/of_get_dma_parent in as appropriate.

Robin.

> +		*host = NULL;
> +		/* Get parent & match bus type */
> +		parent = of_get_parent(dev);
> +		if (parent == NULL)
> +			goto bail;
> +	}
> +
>   	bus = of_match_bus(parent);
>   
>   	/* Count address cells & copy address locally */
> @@ -665,7 +668,7 @@ u64 of_translate_address(struct device_node *dev, const __be32 *in_addr)
>   	struct device_node *host;
>   	u64 ret;
>   
> -	ret = __of_translate_address(dev, in_addr, "ranges", &host);
> +	ret = __of_translate_address(dev, NULL, in_addr, "ranges", &host);
>   	if (host) {
>   		of_node_put(host);
>   		return OF_BAD_ADDR;
> @@ -680,7 +683,7 @@ u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr)
>   	struct device_node *host;
>   	u64 ret;
>   
> -	ret = __of_translate_address(dev, in_addr, "dma-ranges", &host);
> +	ret = __of_translate_address(dev, NULL, in_addr, "dma-ranges", &host);
>   
>   	if (host) {
>   		of_node_put(host);
> @@ -736,7 +739,7 @@ static u64 of_translate_ioport(struct device_node *dev, const __be32 *in_addr,
>   	unsigned long port;
>   	struct device_node *host;
>   
> -	taddr = __of_translate_address(dev, in_addr, "ranges", &host);
> +	taddr = __of_translate_address(dev, NULL, in_addr, "ranges", &host);
>   	if (host) {
>   		/* host-specific port access */
>   		port = logic_pio_trans_hwaddr(&host->fwnode, taddr, size);
>