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of: address: Add support for the parent DMA bus 

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-mem" for those use-cases.

Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>
hifive-unleashed-5.2
Maxime Ripard 2019-04-01 10:56:44 +02:00 committed by Rob Herring
parent 95835a8d47
commit f83a6e5dea
1 changed files with 26 additions and 2 deletions
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28
drivers/of/address.c
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@ -677,12 +677,30 @@ 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(const struct device_node *np)
{
struct of_phandle_args args;
int ret, index;
index = of_property_match_string(np, "interconnect-names", "dma-mem");
if (index < 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 *host;
u64 ret;
ret = __of_translate_address(dev, of_get_parent,
ret = __of_translate_address(dev, __of_get_dma_parent,
in_addr, "dma-ranges", &host);
if (host) {
@ -912,9 +930,15 @@ 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;