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

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

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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