[PATCH v2 4/8] dm: Introduce xxx_get_dma_range()

[Matthias Brugger]

On 10/12/2020 10:42, Nicolas Saenz Julienne wrote:
> Add the following functions to get a specific device's DMA ranges:
>  - dev_get_dma_range()
>  - ofnode_get_dma_range()
>  - of_get_dma_range()
>  - fdt_get_dma_range()
> They are specially useful in oder to be able validate a physical address
> space range into a bus's and to convert addresses from and to address
> spaces.
> 
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne at suse.de>
> 
> ---
> Changes since v1:
>  - Fix wrong arguments in of_get_dma_range()'s call to of_translate_dma_address()
>  - Fix build in SPL/TPL and no LIBFDT supprt
>  - Add missing declaration in 'core/read.c'
>  - Address Matthias' comments
> 
>  common/fdt_support.c   | 73 ++++++++++++++++++++++++++++++++++++++++++
>  drivers/core/of_addr.c | 71 ++++++++++++++++++++++++++++++++++++++++
>  drivers/core/ofnode.c  |  9 ++++++
>  drivers/core/read.c    |  9 ++++++
>  include/dm/of_addr.h   | 17 ++++++++++
>  include/dm/ofnode.h    | 16 +++++++++
>  include/dm/read.h      | 21 ++++++++++++
>  include/fdt_support.h  | 14 ++++++++
>  8 files changed, 230 insertions(+)
> 
> diff --git a/common/fdt_support.c b/common/fdt_support.c
> index 5ae75df3c6..4bcd6720d2 100644
> --- a/common/fdt_support.c
> +++ b/common/fdt_support.c
> @@ -1342,6 +1342,79 @@ u64 fdt_translate_dma_address(const void *blob, int node_offset,
>  	return __of_translate_address(blob, node_offset, in_addr, "dma-ranges");
>  }
>  
> +int fdt_get_dma_range(const void *blob, int node, phys_addr_t *cpu,
> +		      dma_addr_t *bus, u64 *size)
> +{
> +	bool found_dma_ranges = false;
> +	struct of_bus *bus_node;
> +	const fdt32_t *ranges;
> +	int na, ns, pna, pns;
> +	int parent = node;
> +	int ret = 0;
> +	int len;
> +
> +	/* Find the closest dma-ranges property */
> +	while (parent >= 0) {
> +		ranges = fdt_getprop(blob, parent, "dma-ranges", &len);
> +
> +		/* Ignore empty ranges, they imply no translation required */
> +		if (ranges && len > 0)
> +			break;
> +
> +		/* Once we find 'dma-ranges', then a missing one is an error */
> +		if (found_dma_ranges && !ranges) {
> +			ret = -ENODEV;
> +			goto out;
> +		}
> +
> +		if (ranges)
> +			found_dma_ranges = true;
> +
> +		parent = fdt_parent_offset(blob, parent);
> +	}
> +
> +	if (!ranges || parent < 0) {
> +		debug("no dma-ranges found for node %s\n",
> +		      fdt_get_name(blob, node, NULL));
> +		ret = -ENODEV;
> +		goto out;
> +	}
> +
> +	/* switch to that node */
> +	node = parent;
> +	parent = fdt_parent_offset(blob, node);
> +	if (parent < 0) {
> +		printf("Found dma-ranges in root node, shoudln't happen\n");
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	/* Get the address sizes both for the bus and its parent */
> +	bus_node = of_match_bus(blob, node);
> +	bus_node->count_cells(blob, node, &na, &ns);
> +	if (!OF_CHECK_COUNTS(na, ns)) {
> +		printf("%s: Bad cell count for %s\n", __FUNCTION__,
> +		       fdt_get_name(blob, node, NULL));
> +		return -EINVAL;
> +		goto out;
> +	}
> +
> +	bus_node = of_match_bus(blob, parent);
> +	bus_node->count_cells(blob, parent, &pna, &pns);
> +	if (!OF_CHECK_COUNTS(pna, pns)) {
> +		printf("%s: Bad cell count for %s\n", __FUNCTION__,
> +		       fdt_get_name(blob, parent, NULL));
> +		return -EINVAL;
> +		goto out;
> +	}
> +
> +	*bus = fdt_read_number(ranges, na);
> +	*cpu = fdt_translate_dma_address(blob, node, ranges + na);
> +	*size = fdt_read_number(ranges + na + pna, ns);
> +out:
> +	return ret;
> +}
> +
>  /**
>   * fdt_node_offset_by_compat_reg: Find a node that matches compatiable and
>   * who's reg property matches a physical cpu address
> diff --git a/drivers/core/of_addr.c b/drivers/core/of_addr.c
> index ca34d84922..b1d6165b0a 100644
> --- a/drivers/core/of_addr.c
> +++ b/drivers/core/of_addr.c
> @@ -325,6 +325,77 @@ u64 of_translate_dma_address(const struct device_node *dev, const __be32 *in_add
>  	return __of_translate_address(dev, in_addr, "dma-ranges");
>  }
>  
> +int of_get_dma_range(const struct device_node *dev, phys_addr_t *cpu,
> +		     dma_addr_t *bus, u64 *size)
> +{
> +	bool found_dma_ranges = false;
> +	struct device_node *parent;
> +	struct of_bus *bus_node;
> +	int na, ns, pna, pns;
> +	const __be32 *ranges;
> +	int ret = 0;
> +	int len;
> +
> +	/* Find the closest dma-ranges property */
> +	while (dev) {
> +		ranges = of_get_property(dev, "dma-ranges", &len);
> +
> +		/* Ignore empty ranges, they imply no translation required */
> +		if (ranges && len > 0)
> +			break;
> +
> +		/* Once we find 'dma-ranges', then a missing one is an error */
> +		if (found_dma_ranges && !ranges) {
> +			ret = -ENODEV;
> +			goto out;
> +		}
> +
> +		if (ranges)
> +			found_dma_ranges = true;
> +
> +		dev = of_get_parent(dev);
> +	}
> +
> +	if (!dev || !ranges) {
> +		debug("no dma-ranges found for node %s\n",
> +		      of_node_full_name(dev));
> +		ret = -ENODEV;
> +		goto out;
> +	}
> +
> +	/* switch to that node */
> +	parent = of_get_parent(dev);
> +	if (!parent) {
> +		printf("Found dma-ranges in root node, shoudln't happen\n");
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +

Although the function is a dummy, we should put of_node_put() here, to be in
sync with the rest of the code.

Regards,
Matthias