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

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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 <[email protected]>

---
commit 45d4a23317c459865ec740c80b6e2a2ad9f53fd3
tree 432b5e41ef5f231dd57eb1a98f103239c62d63a0
parent 8176dee014ec6ad1039b8c0075c9c1d02147c2c8
author Kumar Gala <[email protected]> Thu, 09 Mar 2006 12:34:25 -0600 committer Kumar Gala <[email protected]> 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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