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Message-ID: <54C6CCF3.7080308@ti.com>
Date: Mon, 26 Jan 2015 18:25:39 -0500
From: Murali Karicheri <m-karicheri2@...com>
To: Bjorn Helgaas <bhelgaas@...gle.com>
CC: <linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <linux-pci@...r.kernel.org>,
<devicetree@...r.kernel.org>, <iommu@...ts.linux-foundation.org>,
Joerg Roedel <joro@...tes.org>,
Grant Likely <grant.likely@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Will Deacon <will.deacon@....com>,
Russell King <linux@....linux.org.uk>,
Arnd Bergmann <arnd@...db.de>,
Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
Subject: Re: [PATCH v4 4/6] of/pci: add of_pci_dma_configure() update dma
configuration
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@...tes.org>
>> Cc: Grant Likely<grant.likely@...aro.org>
>> Cc: Rob Herring<robh+dt@...nel.org>
>> Cc: Bjorn Helgaas<bhelgaas@...gle.com>
>> Cc: Will Deacon<will.deacon@....com>
>> Cc: Russell King<linux@....linux.org.uk>
>> Cc: Arnd Bergmann<arnd@...db.de>
>> Cc: Suravee Suthikulpanit<Suravee.Suthikulpanit@....com>
>>
>> Signed-off-by: Murali Karicheri<m-karicheri2@...com>
>> ---
>> 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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