[v3,4/7] of: address: Add support for the parent DMA bus

Message ID fc76568f10be15b0dfc7515d6affecb20de3e479.1549897336.git-series.maxime.ripard@bootlin.com
State Needs Review / ACK
Headers show
Series
  • sunxi: Add DT representation for the MBUS controller
Related show

Checks

Context Check Description
robh/checkpatch success

Commit Message

Maxime Ripard Feb. 11, 2019, 3:02 p.m.
Some SoCs have devices that are using a separate bus from the main bus to
perform DMA.

These buses might have some restrictions and/or different mapping than from
the CPU side, so we'd need to express those using the usual dma-ranges, but
using a different DT node than the node's parent.

Now that the generic interconnect bindings are available, we can model an
interconnect with the reserved name "dma" for those use-cases.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
---
 drivers/of/address.c | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

Comments

Robin Murphy Feb. 12, 2019, 6:15 p.m. | #1
On 11/02/2019 15:02, Maxime Ripard wrote:
> Some SoCs have devices that are using a separate bus from the main bus to
> perform DMA.
> 
> These buses might have some restrictions and/or different mapping than from
> the CPU side, so we'd need to express those using the usual dma-ranges, but
> using a different DT node than the node's parent.
> 
> Now that the generic interconnect bindings are available, we can model an
> interconnect with the reserved name "dma" for those use-cases.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> ---
>   drivers/of/address.c | 34 +++++++++++++++++++++++++++++++---
>   1 file changed, 31 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index 4c5dc21c71ca..0e9d87a664f5 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -583,8 +583,8 @@ static u64 __of_translate_address(struct device_node *dev,
>   	/* Increase refcount at current level */
>   	of_node_get(dev);
>   
> +	*host = NULL;
>   	if (!parent) {
> -		*host = NULL;
>   		/* Get parent & match bus type */
>   		parent = of_get_parent(dev);
>   		if (parent == NULL)
> @@ -678,12 +678,34 @@ u64 of_translate_address(struct device_node *dev, const __be32 *in_addr)
>   }
>   EXPORT_SYMBOL(of_translate_address);
>   
> +static struct device_node *__of_get_dma_parent(struct device_node *np)
> +{
> +	struct of_phandle_args args;
> +	unsigned int index;
> +	int ret;
> +
> +	ret = of_property_match_string(np, "interconnect-names", "dma");
> +	if (ret < 0)
> +		return of_get_parent(np);

Don't you need to propagate ret to index here?

Robin.

> +
> +	ret = of_parse_phandle_with_args(np, "interconnects",
> +					 "#interconnect-cells",
> +					 index, &args);
> +	if (ret < 0)
> +		return of_get_parent(np);
> +
> +	return of_node_get(args.np);
> +}
> +
>   u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr)
>   {
> +	struct device_node *parent;
>   	struct device_node *host;
>   	u64 ret;
>   
> -	ret = __of_translate_address(dev, NULL, in_addr, "dma-ranges", &host);
> +	parent = __of_get_dma_parent(dev);
> +	ret = __of_translate_address(dev, parent, in_addr, "dma-ranges", &host);
> +	of_node_put(parent);
>   
>   	if (host) {
>   		of_node_put(host);
> @@ -911,9 +933,15 @@ int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *siz
>   		return -EINVAL;
>   
>   	while (1) {
> +		struct device_node *parent;
> +
>   		naddr = of_n_addr_cells(node);
>   		nsize = of_n_size_cells(node);
> -		node = of_get_next_parent(node);
> +
> +		parent = __of_get_dma_parent(node);
> +		of_node_put(node);
> +
> +		node = parent;
>   		if (!node)
>   			break;
>   
>

Patch

diff --git a/drivers/of/address.c b/drivers/of/address.c
index 4c5dc21c71ca..0e9d87a664f5 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -583,8 +583,8 @@  static u64 __of_translate_address(struct device_node *dev,
 	/* Increase refcount at current level */
 	of_node_get(dev);
 
+	*host = NULL;
 	if (!parent) {
-		*host = NULL;
 		/* Get parent & match bus type */
 		parent = of_get_parent(dev);
 		if (parent == NULL)
@@ -678,12 +678,34 @@  u64 of_translate_address(struct device_node *dev, const __be32 *in_addr)
 }
 EXPORT_SYMBOL(of_translate_address);
 
+static struct device_node *__of_get_dma_parent(struct device_node *np)
+{
+	struct of_phandle_args args;
+	unsigned int index;
+	int ret;
+
+	ret = of_property_match_string(np, "interconnect-names", "dma");
+	if (ret < 0)
+		return of_get_parent(np);
+
+	ret = of_parse_phandle_with_args(np, "interconnects",
+					 "#interconnect-cells",
+					 index, &args);
+	if (ret < 0)
+		return of_get_parent(np);
+
+	return of_node_get(args.np);
+}
+
 u64 of_translate_dma_address(struct device_node *dev, const __be32 *in_addr)
 {
+	struct device_node *parent;
 	struct device_node *host;
 	u64 ret;
 
-	ret = __of_translate_address(dev, NULL, in_addr, "dma-ranges", &host);
+	parent = __of_get_dma_parent(dev);
+	ret = __of_translate_address(dev, parent, in_addr, "dma-ranges", &host);
+	of_node_put(parent);
 
 	if (host) {
 		of_node_put(host);
@@ -911,9 +933,15 @@  int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *siz
 		return -EINVAL;
 
 	while (1) {
+		struct device_node *parent;
+
 		naddr = of_n_addr_cells(node);
 		nsize = of_n_size_cells(node);
-		node = of_get_next_parent(node);
+
+		parent = __of_get_dma_parent(node);
+		of_node_put(node);
+
+		node = parent;
 		if (!node)
 			break;