linux-kernel - [PATCH v4 06/29] PCI: pci resource iterator

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Message-Id: <1365806683-26717-7-git-send-email-yinghai@kernel.org>
Date:	Fri, 12 Apr 2013 15:44:20 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	Bjorn Helgaas <bhelgaas@...gle.com>, Ram Pai <linuxram@...ibm.com>
Cc:	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	Yinghai Lu <yinghai@...nel.org>
Subject: [PATCH v4 06/29] PCI: pci resource iterator

From: Ram Pai <linuxram@...ibm.com>

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.

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

-v2: Consolidated iterator interface as per Bjorn's suggestion.
-v3: Add the idx back - Yinghai Lu
-v7: Change to use bitmap for searching - Yinghai Lu
-v8: Fix acpiphp module compiling error that is found by
	Steven Newbury <steve@...wbury.org.uk> - Yinghai Lu
-v9: According to Bjorn, remove PCI_NO_... that is too confusing
				- Yinghai Lu

Signed-off-by: Ram Pai <linuxram@...ibm.com>
Signed-off-by: Yinghai Lu <yinghai@...nel.org>
---
 drivers/pci/probe.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/pci.h | 24 ++++++++++++++++++++++++
 2 files changed, 72 insertions(+)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 1df75f7..ac751a6 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -123,6 +123,54 @@ int pci_dev_resource_idx(struct pci_dev *dev, struct resource *res)
 	return -1;
 }
 
+static void __init_res_idx_mask(unsigned long *mask, int flag)
+{
+	bitmap_zero(mask, PCI_NUM_RESOURCES);
+	if (flag & PCI_STD_RES)
+		bitmap_set(mask, PCI_STD_RESOURCES,
+			PCI_STD_RESOURCE_END - PCI_STD_RESOURCES + 1);
+	if (flag & PCI_ROM_RES)
+		bitmap_set(mask, PCI_ROM_RESOURCE, 1);
+#ifdef CONFIG_PCI_IOV
+	if (flag & PCI_IOV_RES)
+		bitmap_set(mask, PCI_IOV_RESOURCES,
+			PCI_IOV_RESOURCE_END - PCI_IOV_RESOURCES + 1);
+#endif
+	if (flag & PCI_BRIDGE_RES)
+		bitmap_set(mask, PCI_BRIDGE_RESOURCES,
+			PCI_BRIDGE_RESOURCE_END - PCI_BRIDGE_RESOURCES + 1);
+}
+
+static DECLARE_BITMAP(res_idx_mask[1 << PCI_RES_BLOCK_NUM], PCI_NUM_RESOURCES);
+static int __init pci_res_idx_mask_init(void)
+{
+	int i;
+
+	for (i = 0; i < (1 << PCI_RES_BLOCK_NUM); i++)
+		__init_res_idx_mask(res_idx_mask[i], i);
+
+	return 0;
+}
+postcore_initcall(pci_res_idx_mask_init);
+
+static inline unsigned long *get_res_idx_mask(int flag)
+{
+	return res_idx_mask[flag & ((1 << PCI_RES_BLOCK_NUM) - 1)];
+}
+
+int pci_next_resource_idx(int i, int flag)
+{
+	i++;
+	if (i < PCI_NUM_RESOURCES)
+		i = find_next_bit(get_res_idx_mask(flag), PCI_NUM_RESOURCES, i);
+
+	if (i < PCI_NUM_RESOURCES)
+		return i;
+
+	return -1;
+}
+EXPORT_SYMBOL(pci_next_resource_idx);
+
 static u64 pci_size(u64 base, u64 maxbase, u64 mask)
 {
 	u64 size = mask & maxbase;	/* Find the significant bits */
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 14b7de4..044c474 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -379,6 +379,30 @@ struct pci_dev {
 struct resource *pci_dev_resource_n(struct pci_dev *dev, int n);
 int pci_dev_resource_idx(struct pci_dev *dev, struct resource *res);
 
+#define PCI_STD_RES		(1<<0)
+#define PCI_ROM_RES		(1<<1)
+#define PCI_IOV_RES		(1<<2)
+#define PCI_BRIDGE_RES		(1<<3)
+#define PCI_RES_BLOCK_NUM	4
+
+#define PCI_ALL_RES		(PCI_STD_RES | PCI_ROM_RES | PCI_BRIDGE_RES | PCI_IOV_RES)
+#define PCI_ROM_IOV_BRIDGE_RES	(PCI_ROM_RES | PCI_BRIDGE_RES | PCI_IOV_RES)
+#define PCI_STD_ROM_BRIDGE_RES	(PCI_STD_RES | PCI_ROM_RES | PCI_BRIDGE_RES)
+#define PCI_STD_IOV_BRIDGE_RES	(PCI_STD_RES | PCI_IOV_RES | PCI_BRIDGE_RES)
+#define PCI_STD_ROM_IOV_RES	(PCI_STD_RES | PCI_ROM_RES | PCI_IOV_RES)
+#define PCI_STD_ROM_RES		(PCI_STD_RES | PCI_ROM_RES)
+#define PCI_STD_IOV_RES		(PCI_STD_RES | PCI_IOV_RES)
+#define PCI_STD_ROM_IOV_RES	(PCI_STD_RES | PCI_ROM_RES | PCI_IOV_RES)
+
+int pci_next_resource_idx(int i, int flag);
+
+#define for_each_pci_resource(dev, res, i, flag)	\
+	for (i = pci_next_resource_idx(-1, flag),	\
+		res = pci_dev_resource_n(dev, i);	\
+	     res;					\
+	     i = pci_next_resource_idx(i, flag),	\
+		res = pci_dev_resource_n(dev, i))
+
 static inline struct pci_dev *pci_physfn(struct pci_dev *dev)
 {
 #ifdef CONFIG_PCI_IOV
-- 
1.8.1.4

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