[RFC PATCH] of: Fix DMA configuration for non-DT masters
Robin Murphy
robin.murphy at arm.com
Tue Mar 28 11:57:22 PDT 2017
For PCI masters not represented in DT, we pass the OF node of their
associated host bridge to of_dma_configure(), such that they can inherit
the appropriate DMA configuration from whatever is described there.
Unfortunately, whilst this has worked for the "dma-coherent" property,
it turns out to miss the case where the host bridge node has a non-empty
"dma-ranges", since nobody is expecting the 'device' to be a bus itself.
It transpires, though, that the de-facto interface since the prototype
change in 1f5c69aa51f9 ("of: Move of_dma_configure() to device.c to help
re-use") is very clear-cut: either the master_np argument is redundant
with dev->of_node, or dev->of_node is NULL and master_np is the relevant
parent bus. Let's ratify that behaviour, then teach the whole
of_dma_configure() pipeline to cope with both cases properly.
Signed-off-by: Robin Murphy <robin.murphy at arm.com>
---
This is what I'd consider the better fix - rather than adding yet more
special cases - which will also make it simple to handle multiple
"dma-ranges" entries with minimal further disruption. The callers now
left passing dev->of_node as 'parent' are harmless, but look a bit silly
and clearly want cleaning up - I'd be partial to renaming the existing
function and having a single-argument wrapper for the 'normal' case, e.g.:
static inline int of_dma_configure(struct device_node *dev)
{
return of_dma_configure_parent(dev, NULL);
}
Thoughts?
Robin.
drivers/iommu/of_iommu.c | 7 ++++---
drivers/of/address.c | 37 +++++++++++++++++++++++++------------
drivers/of/device.c | 12 +++++++-----
include/linux/of_address.h | 7 ++++---
include/linux/of_device.h | 4 ++--
include/linux/of_iommu.h | 4 ++--
6 files changed, 44 insertions(+), 27 deletions(-)
diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 2683e9fc0dcf..35aff07bb5eb 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -138,21 +138,22 @@ static const struct iommu_ops
}
const struct iommu_ops *of_iommu_configure(struct device *dev,
- struct device_node *master_np)
+ struct device_node *parent)
{
struct of_phandle_args iommu_spec;
- struct device_node *np;
+ struct device_node *np, *master_np;
const struct iommu_ops *ops = NULL;
int idx = 0;
if (dev_is_pci(dev))
- return of_pci_iommu_configure(to_pci_dev(dev), master_np);
+ return of_pci_iommu_configure(to_pci_dev(dev), parent);
/*
* We don't currently walk up the tree looking for a parent IOMMU.
* See the `Notes:' section of
* Documentation/devicetree/bindings/iommu/iommu.txt
*/
+ master_np = dev->of_node ? dev->of_node : parent;
while (!of_parse_phandle_with_args(master_np, "iommus",
"#iommu-cells", idx,
&iommu_spec)) {
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 02b2903fe9d2..833bc17f5e55 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -808,6 +808,7 @@ EXPORT_SYMBOL(of_io_request_and_map);
/**
* of_dma_get_range - Get DMA range info
* @np: device node to get DMA range info
+ * @parent: node of device's parent bus, if @np is NULL
* @dma_addr: pointer to store initial DMA address of DMA range
* @paddr: pointer to store initial CPU address of DMA range
* @size: pointer to store size of DMA range
@@ -822,36 +823,48 @@ EXPORT_SYMBOL(of_io_request_and_map);
* It returns -ENODEV if "dma-ranges" property was not found
* for this device in DT.
*/
-int of_dma_get_range(struct device_node *np, u64 *dma_addr, u64 *paddr, u64 *size)
+int of_dma_get_range(struct device_node *np, struct device_node *parent,
+ u64 *dma_addr, u64 *paddr, u64 *size)
{
- struct device_node *node = of_node_get(np);
+ struct device_node *node;
const __be32 *ranges = NULL;
int len, naddr, nsize, pna;
int ret = 0;
u64 dmaaddr;
- if (!node)
- return -EINVAL;
-
- while (1) {
+ if (np) {
+ node = of_node_get(np);
naddr = of_n_addr_cells(node);
nsize = of_n_size_cells(node);
node = of_get_next_parent(node);
- if (!node)
- break;
+ } else if (parent) {
+ node = of_node_get(parent);
+ np = parent;
+ if (of_property_read_u32(node, "#address-cells", &naddr))
+ naddr = of_n_addr_cells(node);
+ if (of_property_read_u32(node, "#size-cells", &nsize))
+ nsize = of_n_size_cells(node);
+ } else {
+ return -EINVAL;
+ }
+ while (node) {
ranges = of_get_property(node, "dma-ranges", &len);
- /* Ignore empty ranges, they imply no translation required */
- if (ranges && len > 0)
- break;
-
/*
* At least empty ranges has to be defined for parent node if
* DMA is supported
*/
if (!ranges)
break;
+
+ /* Ignore empty ranges, they imply no translation required */
+ if (len > 0)
+ break;
+
+ naddr = of_n_addr_cells(node);
+ nsize = of_n_size_cells(node);
+ node = of_get_next_parent(node);
}
if (!ranges) {
diff --git a/drivers/of/device.c b/drivers/of/device.c
index 9bb8518b28f2..57ec5324ed6c 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -73,7 +73,8 @@ int of_device_add(struct platform_device *ofdev)
/**
* of_dma_configure - Setup DMA configuration
* @dev: Device to apply DMA configuration
- * @np: Pointer to OF node having DMA configuration
+ * @parent: OF node of device's parent bus, if @dev is not
+ * represented in DT (i.e. @dev->of_node is NULL)
*
* Try to get devices's DMA configuration from DT and update it
* accordingly.
@@ -82,13 +83,14 @@ int of_device_add(struct platform_device *ofdev)
* can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
* to fix up DMA configuration.
*/
-void of_dma_configure(struct device *dev, struct device_node *np)
+void of_dma_configure(struct device *dev, struct device_node *parent)
{
u64 dma_addr, paddr, size;
int ret;
bool coherent;
unsigned long offset;
const struct iommu_ops *iommu;
+ struct device_node *np = dev->of_node;
/*
* Set default coherent_dma_mask to 32 bit. Drivers are expected to
@@ -104,7 +106,7 @@ void of_dma_configure(struct device *dev, struct device_node *np)
if (!dev->dma_mask)
dev->dma_mask = &dev->coherent_dma_mask;
- ret = of_dma_get_range(np, &dma_addr, &paddr, &size);
+ ret = of_dma_get_range(np, parent, &dma_addr, &paddr, &size);
if (ret < 0) {
dma_addr = offset = 0;
size = dev->coherent_dma_mask + 1;
@@ -132,11 +134,11 @@ void of_dma_configure(struct device *dev, struct device_node *np)
dev->coherent_dma_mask = DMA_BIT_MASK(ilog2(dma_addr + size));
*dev->dma_mask = dev->coherent_dma_mask;
- coherent = of_dma_is_coherent(np);
+ coherent = of_dma_is_coherent(np ? np : parent);
dev_dbg(dev, "device is%sdma coherent\n",
coherent ? " " : " not ");
- iommu = of_iommu_configure(dev, np);
+ iommu = of_iommu_configure(dev, parent);
dev_dbg(dev, "device is%sbehind an iommu\n",
iommu ? " " : " not ");
diff --git a/include/linux/of_address.h b/include/linux/of_address.h
index 37864734ca50..f1a507f3ae57 100644
--- a/include/linux/of_address.h
+++ b/include/linux/of_address.h
@@ -52,8 +52,8 @@ extern int of_pci_range_parser_init(struct of_pci_range_parser *parser,
extern struct of_pci_range *of_pci_range_parser_one(
struct of_pci_range_parser *parser,
struct of_pci_range *range);
-extern int of_dma_get_range(struct device_node *np, u64 *dma_addr,
- u64 *paddr, u64 *size);
+extern int of_dma_get_range(struct device_node *np, struct device_node *parent,
+ u64 *dma_addr, u64 *paddr, u64 *size);
extern bool of_dma_is_coherent(struct device_node *np);
#else /* CONFIG_OF_ADDRESS */
static inline void __iomem *of_io_request_and_map(struct device_node *device,
@@ -95,7 +95,8 @@ static inline struct of_pci_range *of_pci_range_parser_one(
return NULL;
}
-static inline int of_dma_get_range(struct device_node *np, u64 *dma_addr,
+static inline int of_dma_get_range(struct device_node *np,
+ struct device_node *parent, u64 *dma_addr,
u64 *paddr, u64 *size)
{
return -ENODEV;
diff --git a/include/linux/of_device.h b/include/linux/of_device.h
index c12dace043f3..bcd2b6fbeef3 100644
--- a/include/linux/of_device.h
+++ b/include/linux/of_device.h
@@ -55,7 +55,7 @@ static inline struct device_node *of_cpu_device_node_get(int cpu)
return of_node_get(cpu_dev->of_node);
}
-void of_dma_configure(struct device *dev, struct device_node *np);
+void of_dma_configure(struct device *dev, struct device_node *parent);
#else /* CONFIG_OF */
static inline int of_driver_match_device(struct device *dev,
@@ -103,7 +103,7 @@ static inline struct device_node *of_cpu_device_node_get(int cpu)
{
return NULL;
}
-static inline void of_dma_configure(struct device *dev, struct device_node *np)
+static inline void of_dma_configure(struct device *dev, struct device_node *parent)
{}
#endif /* CONFIG_OF */
diff --git a/include/linux/of_iommu.h b/include/linux/of_iommu.h
index 13394ac83c66..c02b62e8e6ed 100644
--- a/include/linux/of_iommu.h
+++ b/include/linux/of_iommu.h
@@ -12,7 +12,7 @@ extern int of_get_dma_window(struct device_node *dn, const char *prefix,
size_t *size);
extern const struct iommu_ops *of_iommu_configure(struct device *dev,
- struct device_node *master_np);
+ struct device_node *parent);
#else
@@ -24,7 +24,7 @@ static inline int of_get_dma_window(struct device_node *dn, const char *prefix,
}
static inline const struct iommu_ops *of_iommu_configure(struct device *dev,
- struct device_node *master_np)
+ struct device_node *parent)
{
return NULL;
}
--
2.11.0.dirty
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