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[v4,4/6] of/pci: add of_pci_dma_configure() update dma configuration

Message ID 54C6CCF3.7080308@ti.com (mailing list archive)
State New, archived
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Commit Message

Murali Karicheri Jan. 26, 2015, 11:25 p.m. UTC
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@8bytes.org>
>> Cc: Grant Likely<grant.likely@linaro.org>
>> Cc: Rob Herring<robh+dt@kernel.org>
>> Cc: Bjorn Helgaas<bhelgaas@google.com>
>> Cc: Will Deacon<will.deacon@arm.com>
>> Cc: Russell King<linux@arm.linux.org.uk>
>> Cc: Arnd Bergmann<arnd@arndb.de>
>> Cc: Suravee Suthikulpanit<Suravee.Suthikulpanit@amd.com>
>>
>> Signed-off-by: Murali Karicheri<m-karicheri2@ti.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?

  {
@@ -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
>>

Comments

Bjorn Helgaas Jan. 26, 2015, 11:59 p.m. UTC | #1
On Mon, Jan 26, 2015 at 5:25 PM, Murali Karicheri <m-karicheri2@ti.com> wrote:
> 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@8bytes.org>
>>> Cc: Grant Likely<grant.likely@linaro.org>
>>> Cc: Rob Herring<robh+dt@kernel.org>
>>> Cc: Bjorn Helgaas<bhelgaas@google.com>
>>> Cc: Will Deacon<will.deacon@arm.com>
>>> Cc: Russell King<linux@arm.linux.org.uk>
>>> Cc: Arnd Bergmann<arnd@arndb.de>
>>> Cc: Suravee Suthikulpanit<Suravee.Suthikulpanit@amd.com>
>>>
>>> Signed-off-by: Murali Karicheri<m-karicheri2@ti.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?

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

> 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
Murali Karicheri Jan. 27, 2015, 6:14 p.m. UTC | #2
On 01/26/2015 06:59 PM, Bjorn Helgaas wrote:
> On Mon, Jan 26, 2015 at 5:25 PM, Murali Karicheri<m-karicheri2@ti.com>  wrote:
>> 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.
>>>>
   -- Cut ---
>>>>
>>>> Signed-off-by: Murali Karicheri<m-karicheri2@ti.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?
>
> 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,

Thanks. I agree with your suggestion even though the convention is not 
followed fully :) of_pci_get_devfn(), of_get_pci_domain_nr(), 
of_pci_get_host_bridge_resources() are some of those functions not 
following the convention. I plan to change the function as below. Also 
want to name functions as pci_get/put_host_bridge_device() as existing 
function find_pci_host_bridge() is actually returning ptr to struct 
pci_host_bridge  vs the new function returning ptr to device. Here are 
the new functions and how they will be used. Please review and respond 
so that I can avoid a re-spin.

in linux/include/pci.h add the prototypes of 
pci_get/put_host_bridge_device().

in drivers/pci/host-bridge.c add two new functions.

struct device *pci_get_host_bridge_device(struct pci_dev *dev)
{
	struct pci_bus *root_bus = find_pci_root_bus(dev->bus);
	struct device *bridge = root_bus->bridge;

	kobject_get(&bridge->kobj);
	return bridge;
}

void  pci_put_host_bridge_device(struct pci_dev *dev)
{
	struct pci_bus *root_bus = find_pci_root_bus(dev->bus);
	struct device *bridge = root_bus->bridge;

	kobject_put(&bridge->kobj);
}

drivers/of/of_pci.c

void of_pci_dma_configure(struct pci_dev *pci_dev)
{
	struct device *dev = &pci_dev->dev;
	struct device *bridge = pci_get_host_bridge_device(pci_dev);

	of_dma_configure(dev, bridge->parent->of_node);
	pci_put_host_bridge_device(pci_dev);
}

Murali

> Bjorn
>

>>>>
>>
>>
>> --
>> Murali Karicheri
>> Linux Kernel, Texas Instruments
Bjorn Helgaas Jan. 27, 2015, 6:42 p.m. UTC | #3
On Tue, Jan 27, 2015 at 12:14 PM, Murali Karicheri <m-karicheri2@ti.com> wrote:
> On 01/26/2015 06:59 PM, Bjorn Helgaas wrote:
>>
>> On Mon, Jan 26, 2015 at 5:25 PM, Murali Karicheri<m-karicheri2@ti.com>
>> wrote:
>>>
>>> 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.
>>>>>
>   -- Cut ---
>
>>>>>
>>>>> Signed-off-by: Murali Karicheri<m-karicheri2@ti.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?
>>
>>
>> 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,
>
> Thanks. I agree with your suggestion even though the convention is not
> followed fully :) of_pci_get_devfn(), of_get_pci_domain_nr(),
> of_pci_get_host_bridge_resources() are some of those functions not following
> the convention. I plan to change the function as below. Also want to name
> functions as pci_get/put_host_bridge_device() as existing function
> find_pci_host_bridge() is actually returning ptr to struct pci_host_bridge
> vs the new function returning ptr to device. Here are the new functions and
> how they will be used. Please review and respond so that I can avoid a
> re-spin.
>
> in linux/include/pci.h add the prototypes of
> pci_get/put_host_bridge_device().
>
> in drivers/pci/host-bridge.c add two new functions.
>
> struct device *pci_get_host_bridge_device(struct pci_dev *dev)
> {
>         struct pci_bus *root_bus = find_pci_root_bus(dev->bus);
>         struct device *bridge = root_bus->bridge;
>
>         kobject_get(&bridge->kobj);
>         return bridge;
> }

Looks good to me.

> void  pci_put_host_bridge_device(struct pci_dev *dev)
> {
>         struct pci_bus *root_bus = find_pci_root_bus(dev->bus);
>         struct device *bridge = root_bus->bridge;
>
>         kobject_put(&bridge->kobj);
> }

I think I would pass in the "struct device *" here so we don't have to
call find_pci_root_bus() again.

> drivers/of/of_pci.c
>
> void of_pci_dma_configure(struct pci_dev *pci_dev)
> {
>         struct device *dev = &pci_dev->dev;
>         struct device *bridge = pci_get_host_bridge_device(pci_dev);
>
>         of_dma_configure(dev, bridge->parent->of_node);
>         pci_put_host_bridge_device(pci_dev);

Then this would become "pci_put_host_bridge_device(bridge)"

> }
>
> Murali
>
>> Bjorn
>>
>
>>>>>
>>>
>>>
>>> --
>>> Murali Karicheri
>>> Linux Kernel, Texas Instruments
>
>
>
> --
> Murali Karicheri
> Linux Kernel, Texas Instruments
Murali Karicheri Jan. 27, 2015, 6:45 p.m. UTC | #4
On 01/27/2015 01:42 PM, Bjorn Helgaas wrote:
> On Tue, Jan 27, 2015 at 12:14 PM, Murali Karicheri<m-karicheri2@ti.com>  wrote:
>> On 01/26/2015 06:59 PM, Bjorn Helgaas wrote:
>>>
>>> On Mon, Jan 26, 2015 at 5:25 PM, Murali Karicheri<m-karicheri2@ti.com>
>>> wrote:
>>>>
>>>> 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.
>>>>>>
>>    -- Cut ---
>>
>>>>>>
>>>>>> Signed-off-by: Murali Karicheri<m-karicheri2@ti.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?
>>>
>>>
>>> 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,
>>
>> Thanks. I agree with your suggestion even though the convention is not
>> followed fully :) of_pci_get_devfn(), of_get_pci_domain_nr(),
>> of_pci_get_host_bridge_resources() are some of those functions not following
>> the convention. I plan to change the function as below. Also want to name
>> functions as pci_get/put_host_bridge_device() as existing function
>> find_pci_host_bridge() is actually returning ptr to struct pci_host_bridge
>> vs the new function returning ptr to device. Here are the new functions and
>> how they will be used. Please review and respond so that I can avoid a
>> re-spin.
>>
>> in linux/include/pci.h add the prototypes of
>> pci_get/put_host_bridge_device().
>>
>> in drivers/pci/host-bridge.c add two new functions.
>>
>> struct device *pci_get_host_bridge_device(struct pci_dev *dev)
>> {
>>          struct pci_bus *root_bus = find_pci_root_bus(dev->bus);
>>          struct device *bridge = root_bus->bridge;
>>
>>          kobject_get(&bridge->kobj);
>>          return bridge;
>> }
>
> Looks good to me.
>
>> void  pci_put_host_bridge_device(struct pci_dev *dev)
>> {
>>          struct pci_bus *root_bus = find_pci_root_bus(dev->bus);
>>          struct device *bridge = root_bus->bridge;
>>
>>          kobject_put(&bridge->kobj);
>> }
>
> I think I would pass in the "struct device *" here so we don't have to
> call find_pci_root_bus() again.
>
>> drivers/of/of_pci.c
>>
>> void of_pci_dma_configure(struct pci_dev *pci_dev)
>> {
>>          struct device *dev =&pci_dev->dev;
>>          struct device *bridge = pci_get_host_bridge_device(pci_dev);
>>
>>          of_dma_configure(dev, bridge->parent->of_node);
>>          pci_put_host_bridge_device(pci_dev);
>
> Then this would become "pci_put_host_bridge_device(bridge)"

Agree with both. Will become part of my v5 of the series. I am adding 
this as a separate commit.

Murali
>
>> }
>>
>> Murali
>>
>>> Bjorn
>>>
>>
>>>>>>
>>>>
>>>>
>>>> --
>>>> Murali Karicheri
>>>> Linux Kernel, Texas Instruments
>>
>>
>>
>> --
>> Murali Karicheri
>> Linux Kernel, Texas Instruments
diff mbox

Patch

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)