[RFC PATCH] methods to access resources of a struct pci_dev

* [RFC PATCH] methods to access resources of a struct pci_dev
@ 2012-06-18  5:03 Ram Pai
  2012-06-18 18:30 ` Yinghai Lu
  0 siblings, 1 reply; 24+ messages in thread
From: Ram Pai @ 2012-06-18  5:03 UTC (permalink / raw)
  To: linux-pci

PCI: methods to access resources of struct pci_dev

Currently pci_dev structure holds an array of 17 PCI resources; six base
BARs, one ROM BAR, four BRIDGE BARs, six sriov BARs.  This is wasteful.
A bridge device just needs the 4 bridge resources. A non-bridge device
just needs the six base resources and one ROM resource. The sriov
resources are needed only if the device has SRIOV capability.

The pci_dev structure needs to be re-organized to avoid unnecessary
bloating.  However too much code outside the pci-bus driver, assumes the
internal details of the pci_dev structure, thus making it hard to
re-organize the datastructure.

As a first step this patch provides generic methods to access the
resource structure of the pci_dev.

Once this patch is accepted, I have another 40+ patches that modify all
the files that directly access the resource structure, to use the new
methods provided in the first step.

Finally we can re-organize the resource structure in the pci_dev
structure and correspondingly update the methods.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>

diff --git a/include/linux/pci.h b/include/linux/pci.h
index e444f5b..475b10d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1350,6 +1350,58 @@ static inline int pci_domain_nr(struct pci_bus *bus)
 							\
 	 (pci_resource_end((dev), (bar)) -		\
 	  pci_resource_start((dev), (bar)) + 1))
+#define pci_get_std_resource(dev, bar)     (((dev)->resource)+bar)
+#define pci_get_sriov_resource(dev, bar)     (((dev)->resource)+bar+PCI_IOV_RESOURCES)
+#define pci_get_bridge_resource(dev, bar)    (((dev)->resource)+bar+PCI_BRIDGE_RESOURCES)
+#define pci_get_rom_resource(dev)    	     (((dev)->resource)+PCI_ROM_RESOURCE)
+#define pci_resource_number(dev, res)	     (res - (dev)->resource)
+
+/* code that assume the current resource layout will continue to operate */
+static inline struct resource *pci_get_resource(struct pci_dev *pdev, int bar)
+{
+	if (bar >= 0 && bar < PCI_ROM_RESOURCE)
+		return pci_get_std_resource(pdev, bar);
+	else if (bar == PCI_ROM_RESOURCE)
+		return pci_get_rom_resource(pdev);
+	else if (bar <= PCI_IOV_RESOURCE_END)
+		return pci_get_sriov_resource(pdev, bar-PCI_IOV_RESOURCES);
+	else if (bar <= PCI_BRIDGE_RESOURCE_END)
+		return pci_get_bridge_resource(pdev, bar-PCI_BRIDGE_RESOURCES);
+	else
+		return NULL;
+}
+
+#define for_each_resource(dev, res, i) \
+	for (i = 0;	\
+	    (res = pci_get_resource(dev, i)) || i < PCI_NUM_RESOURCES; \
+	     i++)
+
+#define for_each_std_resource(dev, res, i) \
+	for (i = 0;	\
+	    (res = pci_get_std_resource(dev, i)) || i <= PCI_STD_RESOURCE_END; \
+	     i++)
+
+#define for_each_std_and_rom_resource(dev, res, i) \
+	for (i = 0;	\
+	    (res = (i==PCI_ROM_RESOURCE)? pci_get_rom_resource(dev) : \
+			pci_get_std_resource(dev, i)) || \
+			i <= PCI_ROM_RESOURCE; \
+	     i++)
+
+#define for_each_sriov_resource(dev, res, i) \
+	for (i = 0;	\
+	    (res = pci_get_sriov_resource(dev, i)) || i < PCI_SRIOV_NUM_BARS; \
+	     i++)
+
+#define for_each_bridge_resource(dev, res, i) \
+	for (i = 0;	\
+	    (res = pci_get_bridge_resource(dev, i)) || i < PCI_BRIDGE_RESOURCE_NUM; \
+	     i++)
+
+#define pci_get_res_attr(dev, bar) (((dev)->res_attr)[bar])
+#define pci_get_res_attrwc(dev, bar) (((dev)->res_attr_wc)[bar])
+#define pci_set_res_attr(dev, bar, value) (((dev)->res_attr)[bar] = value)
+#define pci_set_res_attrwc(dev, bar, value) (((dev)->res_attr_wc)[bar] = value)

 /* Similar to the helpers above, these manipulate per-pci_dev
  * driver-specific data.  They are really just a wrapper around


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