From: Robin Murphy robin.murphy@arm.com
[ Upstream commit f1ad5338a4d57fe1fe6475003acb8c70bf9d1bdf ]
Commit 951d48855d86 ("of: Make of_dma_get_range() work on bus nodes") relaxed the handling of "dma-ranges" for any leaf node on the assumption that it would still represent a usage error for the property to be present on a non-bus leaf node. However there turns out to be a fiddly case where a bus also represents a DMA-capable device in its own right, such as a PCIe root complex with an integrated DMA engine on its platform side. In such cases, "dma-ranges" translation is entirely valid for devices discovered behind the bus, but should not be erroneously applied to the bus controller device itself which operates in its parent's address space. Fix this by restoring the previous behaviour for the specific case where a device is configured via its own OF node, since it is logical to assume that a device should never represent its own parent bus.
Reported-by: Serge Semin Sergey.Semin@baikalelectronics.ru Signed-off-by: Robin Murphy robin.murphy@arm.com Link: https://lore.kernel.org/r/112e8f3d3e7c054ecf5e12b5ac0aa5596ec00681.166445543... Signed-off-by: Rob Herring robh@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/of/address.c | 4 +++- drivers/of/device.c | 9 ++++++++- drivers/of/of_private.h | 5 +++++ 3 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/of/address.c b/drivers/of/address.c index 73ddf2540f3f..fdacf6c3c91f 100644 --- a/drivers/of/address.c +++ b/drivers/of/address.c @@ -626,7 +626,8 @@ 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) +#ifdef CONFIG_HAS_DMA +struct device_node *__of_get_dma_parent(const struct device_node *np) { struct of_phandle_args args; int ret, index; @@ -643,6 +644,7 @@ static struct device_node *__of_get_dma_parent(const struct device_node *np)
return of_node_get(args.np); } +#endif
static struct device_node *of_get_next_dma_parent(struct device_node *np) { diff --git a/drivers/of/device.c b/drivers/of/device.c index 1122daa8e273..f760199abda6 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -93,12 +93,19 @@ int of_dma_configure_id(struct device *dev, struct device_node *np, { const struct iommu_ops *iommu; const struct bus_dma_region *map = NULL; + struct device_node *bus_np; u64 dma_start = 0; u64 mask, end, size = 0; bool coherent; int ret;
- ret = of_dma_get_range(np, &map); + if (np == dev->of_node) + bus_np = __of_get_dma_parent(np); + else + bus_np = of_node_get(np); + + ret = of_dma_get_range(bus_np, &map); + of_node_put(bus_np); if (ret < 0) { /* * For legacy reasons, we have to assume some devices need diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h index d9e6a324de0a..ffc2099935f5 100644 --- a/drivers/of/of_private.h +++ b/drivers/of/of_private.h @@ -161,12 +161,17 @@ struct bus_dma_region; #if defined(CONFIG_OF_ADDRESS) && defined(CONFIG_HAS_DMA) int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map); +struct device_node *__of_get_dma_parent(const struct device_node *np); #else static inline int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map) { return -ENODEV; } +static inline struct device_node *__of_get_dma_parent(const struct device_node *np) +{ + return of_get_parent(np); +} #endif
#endif /* _LINUX_OF_PRIVATE_H */