Messages in this thread | | | Date | Tue, 27 Jan 2015 13:14:14 -0500 | From | Murali Karicheri <> | Subject | Re: [PATCH v4 4/6] of/pci: add of_pci_dma_configure() update dma configuration |
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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
-- Murali Karicheri Linux Kernel, Texas Instruments
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