Re: [PATCH v4 4/6] of/pci: add of_pci_dma_configure() update dma configuration
From: Murali Karicheri
Date: Mon Jan 26 2015 - 18:26:37 EST
On 01/23/2015 06:41 PM, Bjorn Helgaas wrote:
On Fri, Jan 23, 2015 at 05:32:37PM -0500, Murali Karicheri wrote:
Add of_pci_dma_configure() to allow updating the dma configuration
of the pci device using the configuration from DT of the parent of
the root bridge device.
Cc: Joerg Roedel<joro@xxxxxxxxxx>
Cc: Grant Likely<grant.likely@xxxxxxxxxx>
Cc: Rob Herring<robh+dt@xxxxxxxxxx>
Cc: Bjorn Helgaas<bhelgaas@xxxxxxxxxx>
Cc: Will Deacon<will.deacon@xxxxxxx>
Cc: Russell King<linux@xxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann<arnd@xxxxxxxx>
Cc: Suravee Suthikulpanit<Suravee.Suthikulpanit@xxxxxxx>
Signed-off-by: Murali Karicheri<m-karicheri2@xxxxxx>
---
drivers/of/of_pci.c | 39 +++++++++++++++++++++++++++++++++++++++
include/linux/of_pci.h | 12 ++++++++++++
2 files changed, 51 insertions(+)
diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 88471d3..34878c9 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -2,6 +2,7 @@
#include<linux/export.h>
#include<linux/of.h>
#include<linux/of_address.h>
+#include<linux/of_device.h>
#include<linux/of_pci.h>
#include<linux/slab.h>
@@ -229,6 +230,44 @@ parse_failed:
return err;
}
EXPORT_SYMBOL_GPL(of_pci_get_host_bridge_resources);
+
+/**
+ * of_get_pci_root_bridge_parent - get the OF node of the root bridge's parent
+ * @dev: ptr to pci_dev struct of the pci device
+ *
+ * This function will traverse the bus up to the root bus starting with
+ * the child and return the OF node ptr to root bridge device's parent device.
+ */
+struct device_node *of_get_pci_root_bridge_parent(struct pci_dev *dev)
I'm not an OF person, but this interface seems like it might be too
special-purpose. Maybe it would be enough to add
"of_get_pci_root_bridge()", and the caller could do this:
struct device *bridge = of_get_pci_root_bridge(dev);
struct device_node *parent_np = bridge->parent->of_node;
Also, the name "of_get_..." suggests that it increments a refcount, as
of_get_parent() does. But you aren't doing anything with the refcount.
But I guess an "of_get_pci_root_bridge()" isn't doing anything OF-related,
so maybe we should just add a "pci_get_host_bridge(struct pci_dev *)"
to PCI instead.
Bjorn,
Thanks for the comment.
I think adding pci_get_host_bridge() is a good idea. There is already
similar function in host-bridge.c. I have added this function re-using
existing function find_pci_root_bus(). See the incremental diff below
after this change. Does this look good?
diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 34878c9..77b15b5 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -232,26 +232,6 @@ parse_failed:
EXPORT_SYMBOL_GPL(of_pci_get_host_bridge_resources);
/**
- * of_get_pci_root_bridge_parent - get the OF node of the root bridge's
parent
- * @dev: ptr to pci_dev struct of the pci device
- *
- * This function will traverse the bus up to the root bus starting with
- * the child and return the OF node ptr to root bridge device's parent
device.
- */
-struct device_node *of_get_pci_root_bridge_parent(struct pci_dev *dev)
-{
- struct pci_bus *bus = dev->bus;
- struct device *bridge;
-
- while (!pci_is_root_bus(bus))
- bus = bus->parent;
- bridge = bus->bridge;
-
- return bridge->parent->of_node;
-}
-EXPORT_SYMBOL_GPL(of_get_pci_root_bridge_parent);
-
-/**
* of_pci_dma_configure - Setup DMA configuration
* @dev: ptr to pci_dev struct of the pci device
*
@@ -261,10 +241,9 @@ EXPORT_SYMBOL_GPL(of_get_pci_root_bridge_parent);
void of_pci_dma_configure(struct pci_dev *pci_dev)
{
struct device *dev = &pci_dev->dev;
- struct device_node *parent_np;
+ struct device *bridge = pci_get_host_bridge(pci_dev);
- parent_np = of_get_pci_root_bridge_parent(pci_dev);
- of_dma_configure(dev, parent_np);
+ of_dma_configure(dev, bridge->parent->of_node);
}
EXPORT_SYMBOL_GPL(of_pci_dma_configure);
diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index 0e5f3c9..9803aa6 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c
@@ -23,6 +23,13 @@ static struct pci_host_bridge
*find_pci_host_bridge(struct pci_bus *bus)
return to_pci_host_bridge(root_bus->bridge);
}
+struct device *pci_get_host_bridge(struct pci_dev *dev)
+{
+ struct pci_bus *root_bus = find_pci_root_bus(dev->bus);
+
+ return root_bus->bridge;
+}
+
void pci_set_host_bridge_release(struct pci_host_bridge *bridge,
void (*release_fn)(struct
pci_host_bridge *),
void *release_data)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 9603094..5bcdfa6 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -513,6 +513,8 @@ static inline struct pci_dev
*pci_upstream_bridge(struct pci_dev *dev)
return dev->bus->self;
}
+struct device *pci_get_host_bridge(struct pci_dev *dev);
+
#ifdef CONFIG_PCI_MSI
static inline bool pci_dev_msi_enabled(struct pci_dev *pci_dev)
{
@@ -1823,6 +1825,7 @@ int pci_vpd_find_tag(const u8 *buf, unsigned int
off, unsigned int len, u8 rdt);
int pci_vpd_find_info_keyword(const u8 *buf, unsigned int off,
unsigned int len, const char *kw);
/* PCI <-> OF binding helpers */
#ifdef CONFIG_OF
struct device_node;
Bjorn
+{
+ struct pci_bus *bus = dev->bus;
+ struct device *bridge;
+
+ while (!pci_is_root_bus(bus))
+ bus = bus->parent;
+ bridge = bus->bridge;
+
+ return bridge->parent->of_node;
+}
+EXPORT_SYMBOL_GPL(of_get_pci_root_bridge_parent);
+
+/**
+ * of_pci_dma_configure - Setup DMA configuration
+ * @dev: ptr to pci_dev struct of the pci device
+ *
+ * Function to update PCI devices's DMA configuration using the same
+ * info from the OF node of root host bridge's parent.
+ */
+void of_pci_dma_configure(struct pci_dev *pci_dev)
+{
+ struct device *dev =&pci_dev->dev;
+ struct device_node *parent_np;
+
+ parent_np = of_get_pci_root_bridge_parent(pci_dev);
+ of_dma_configure(dev, parent_np);
+}
+EXPORT_SYMBOL_GPL(of_pci_dma_configure);
+
#endif /* CONFIG_OF_ADDRESS */
#ifdef CONFIG_PCI_MSI
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index ce0e5ab..0465a2a 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -16,6 +16,8 @@ int of_pci_get_devfn(struct device_node *np);
int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin);
int of_pci_parse_bus_range(struct device_node *node, struct resource *res);
int of_get_pci_domain_nr(struct device_node *node);
+struct device_node *of_get_pci_root_bridge_parent(struct pci_dev *dev);
+void of_pci_dma_configure(struct pci_dev *pci_dev);
#else
static inline int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
{
@@ -50,6 +52,16 @@ of_get_pci_domain_nr(struct device_node *node)
{
return -1;
}
+
+static inline struct device_node
+*of_get_pci_root_bridge_parent(struct pci_dev *dev)
+{
+ return NULL;
+}
+
+static inline void of_pci_dma_configure(struct pci_dev *pci_dev)
+{
+}
#endif
#if defined(CONFIG_OF_ADDRESS)
--
1.7.9.5
--
Murali Karicheri
Linux Kernel, Texas Instruments
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