Re: [PATCH] PCI: Add pci_assign_resource_fixed -- allow fixed address assignments

[Kumar Gala <galak@kernel.crashing.org>]

Greg,

My weekly maintainer ping :)

- k

On Mar 20, 2006, at 10:09 AM, Kumar Gala wrote:

> Greg,
>
> Any comments on this?
>
> - kumar
>
> On Mar 10, 2006, at 3:30 PM, Kumar Gala wrote:
>
>>
>> On Mar 10, 2006, at 3:04 PM, Randy.Dunlap wrote:
>>
>>> On Fri, 10 Mar 2006 09:06:32 -0600 (CST) Kumar Gala wrote:
>>>
>>>> On some embedded systems the PCI address for hotplug devices are  
>>>> not only
>>>> known a priori but are required to be at a given PCI address for  
>>>> other
>>>> master in the system to be able to access.
>>>>
>>>> An example of such a system would be an FPGA which is setup from  
>>>> user space
>>>> after the system has booted.  The FPGA may be access by DSPs in  
>>>> the system
>>>> and those DSPs expect the FPGA at a fixed PCI address.
>>>>
>>>> Added pci_assign_resource_fixed() as a way to allow assignment  
>>>> of the PCI
>>>> devices's BARs at fixed PCI addresses.
>>>>
>>>> Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
>>>>
>>>> ---
>>>> commit 45d4a23317c459865ec740c80b6e2a2ad9f53fd3
>>>> tree 432b5e41ef5f231dd57eb1a98f103239c62d63a0
>>>> parent 8176dee014ec6ad1039b8c0075c9c1d02147c2c8
>>>> author Kumar Gala <galak@kernel.crashing.org> Thu, 09 Mar 2006  
>>>> 12:34:25 -0600
>>>> committer Kumar Gala <galak@kernel.crashing.org> Thu, 09 Mar  
>>>> 2006 12:34:25 -0600
>>>>
>>>>  drivers/pci/pci.c       |    1 +
>>>>  drivers/pci/setup-res.c |   35 +++++++++++++++++++++++++++++++++++
>>>>  include/linux/pci.h     |    1 +
>>>>  3 files changed, 37 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>>>> index d2d1879..2557e86 100644
>>>> --- a/drivers/pci/pci.c
>>>> +++ b/drivers/pci/pci.c
>>>> @@ -935,6 +935,7 @@ EXPORT_SYMBOL_GPL(pci_intx);
>>>>  EXPORT_SYMBOL(pci_set_dma_mask);
>>>>  EXPORT_SYMBOL(pci_set_consistent_dma_mask);
>>>>  EXPORT_SYMBOL(pci_assign_resource);
>>>> +EXPORT_SYMBOL(pci_assign_resource_fixed);
>>>>  EXPORT_SYMBOL(pci_find_parent_resource);
>>>>
>>>>  EXPORT_SYMBOL(pci_set_power_state);
>>>> diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
>>>> index ea9277b..f485958 100644
>>>> --- a/drivers/pci/setup-res.c
>>>> +++ b/drivers/pci/setup-res.c
>>>> @@ -155,6 +155,41 @@ int pci_assign_resource(struct pci_dev *
>>>>  	return ret;
>>>>  }
>>>>
>>>> +int pci_assign_resource_fixed(struct pci_dev *dev, int resno)
>>>> +{
>>>> +	struct pci_bus *bus = dev->bus;
>>>> +	struct resource *res = dev->resource + resno;
>>>> +	unsigned int type_mask;
>>>> +	int i, ret = -EBUSY;
>>>> +
>>>> +	type_mask = IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_PREFETCH;
>>>
>>> If type_mask must match (as in comment below), should it be a
>>> parameter instead of hard-coded here?  Does this match your FPGA
>>> resource?  It may not match my <hypothetical> resource.
>>
>> I was trying to ensure an exact match between the bus and device  
>> resource types.  I figured if you were calling this API you should  
>> be able to ensure that the resource types match exactly.
>>
>>>> +	for (i = 0; i < PCI_BUS_NUM_RESOURCES; i++) {
>>>> +		struct resource *r = bus->resource[i];
>>>> +		if (!r)
>>>> +			continue;
>>>> +
>>>> +		/* type_mask must match */
>>>> +		if ((res->flags ^ r->flags) & type_mask)
>>>> +			continue;
>>>> +
>>>> +		ret = request_resource(r, res);
>>>> +
>>>> +		if (ret == 0)
>>>> +			break;
>>>> +	}
>>>> +
>>>> +	if (ret) {
>>>> +		printk(KERN_ERR "PCI: Failed to allocate %s resource #%d:%lx@% 
>>>> lx for %s\n",
>>>> +		       res->flags & IORESOURCE_IO ? "I/O" : "mem",
>>>> +		       resno, res->end - res->start + 1, res->start, pci_name 
>>>> (dev));
>>>> +	} else if (resno < PCI_BRIDGE_RESOURCES) {
>>>> +		pci_update_resource(dev, res, resno);
>>>> +	}
>>>
>>> braces not needed.
>>
>> Fair, need to go find where I stole this from and possibly fix  
>> extra braces there as well.
>>
>>>
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +
>>>
>>>
>>> ---
>>> ~Randy
>>> Please use an email client that implements proper (compliant)  
>>> threading.
>>> (You know who you are.)
>>
>> -
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