[PATCH v4 4/6] of/pci: add of_pci_dma_configure() update dma configuration
From: bhelgaas@google.com (Bjorn Helgaas)
Date: 2015-01-27 00:00:23
Also in:
linux-devicetree, linux-iommu, linux-pci, lkml
On Mon, Jan 26, 2015 at 5:25 PM, Murali Karicheri [off-list ref] wrote:
On 01/23/2015 06:41 PM, Bjorn Helgaas wrote:quoted
On Fri, Jan 23, 2015 at 05:32:37PM -0500, Murali Karicheri wrote:quoted
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@8bytes.org> Cc: Grant Likely<redacted> Cc: Rob Herring<robh+dt@kernel.org> Cc: Bjorn Helgaas<bhelgaas@google.com> Cc: Will Deacon<redacted> Cc: Russell King<redacted> Cc: Arnd Bergmann<arnd@arndb.de> Cc: Suravee Suthikulpanit<Suravee.Suthikulpanit@amd.com> Signed-off-by: Murali Karicheri<redacted> --- 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'sparent + * @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?
I like the implementation, but I think either we need to take a reference on the host bridge, or change the name to something like "pci_find_host_bridge()", because using "_get_" is conventional for functions that acquire a reference. Since host bridges are hot-pluggable, at least in theory, I vote for taking a reference. Then of course, you'd have to add code to drop the reference when you're finished with it. Bjorn
quoted hunk ↗ jump to hunk
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'sparent - * @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(structpci_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;quoted
Bjornquoted
+{ + 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_MSIdiff --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, u8pin); 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