x86/PCI: Infrastructure to maintain a list of FW-assigned BIOS BAR values

Commit 58c84eda075 introduced functionality to try and reinstate the
original BIOS BAR addresses of a PCI device when normal resource
assignment attempts fail.  To keep track of the BIOS BAR addresses,
struct pci_dev was augmented with an array to hold the BAR addresses
of the PCI device: 'resource_size_t fw_addr[DEVICE_COUNT_RESOURCE]'.

The reinstatement of BAR addresses is an uncommon event leaving the
'fw_addr' array unused under normal circumstances.  This functionality
is also currently architecture specific with an implementation limited
to x86.  As the use of struct pci_dev is so prevalent, having the
'fw_addr' array residing within such seems somewhat wasteful.

This patch introduces a stand alone data structure and interfacing
routines for maintaining a list of FW-assigned BIOS BAR value entries.

Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 79 insertions, 0 deletions

diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index 91821a1a0c3a..5a1edf2b5386 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -39,6 +39,85 @@
 #include <asm/io_apic.h>
 
 
+/*
+ * This list of dynamic mappings is for temporarily maintaining
+ * original BIOS BAR addresses for possible reinstatement.
+ */
+struct pcibios_fwaddrmap {
+        struct list_head list;
+        struct pci_dev *dev;
+        resource_size_t fw_addr[DEVICE_COUNT_RESOURCE];
+};
+
+static LIST_HEAD(pcibios_fwaddrmappings);
+static DEFINE_SPINLOCK(pcibios_fwaddrmap_lock);
+
+/* Must be called with 'pcibios_fwaddrmap_lock' lock held. */
+static struct pcibios_fwaddrmap *pcibios_fwaddrmap_lookup(struct pci_dev *dev)
+{
+        struct pcibios_fwaddrmap *map;
+
+        list_for_each_entry(map, &pcibios_fwaddrmappings, list)
+                if (map->dev == dev)
+                        return map;
+
+        return NULL;
+}
+
+static void
+pcibios_save_fw_addr(struct pci_dev *dev, int idx, resource_size_t fw_addr)
+{
+        unsigned long flags;
+        struct pcibios_fwaddrmap *map;
+
+        spin_lock_irqsave(&pcibios_fwaddrmap_lock, flags);
+        map = pcibios_fwaddrmap_lookup(dev);
+        if (!map) {
+                spin_unlock_irqrestore(&pcibios_fwaddrmap_lock, flags);
+                map = kzalloc(sizeof(*map), GFP_KERNEL);
+                if (!map)
+                        return;
+
+                map->dev = pci_dev_get(dev);
+                map->fw_addr[idx] = fw_addr;
+                INIT_LIST_HEAD(&map->list);
+
+                spin_lock_irqsave(&pcibios_fwaddrmap_lock, flags);
+                list_add_tail(&map->list, &pcibios_fwaddrmappings);
+        } else
+                map->fw_addr[idx] = fw_addr;
+        spin_unlock_irqrestore(&pcibios_fwaddrmap_lock, flags);
+}
+
+resource_size_t pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx)
+{
+        unsigned long flags;
+        struct pcibios_fwaddrmap *map;
+        resource_size_t fw_addr = 0;
+
+        spin_lock_irqsave(&pcibios_fwaddrmap_lock, flags);
+        map = pcibios_fwaddrmap_lookup(dev);
+        if (map)
+                fw_addr = map->fw_addr[idx];
+        spin_unlock_irqrestore(&pcibios_fwaddrmap_lock, flags);
+
+        return fw_addr;
+}
+
+static void pcibios_fw_addr_list_del(void)
+{
+        unsigned long flags;
+        struct pcibios_fwaddrmap *entry, *next;
+
+        spin_lock_irqsave(&pcibios_fwaddrmap_lock, flags);
+        list_for_each_entry_safe(entry, next, &pcibios_fwaddrmappings, list) {
+                list_del(&entry->list);
+                pci_dev_put(entry->dev);
+                kfree(entry);
+        }
+        spin_unlock_irqrestore(&pcibios_fwaddrmap_lock, flags);
+}
+
 static int
 skip_isa_ioresource_align(struct pci_dev *dev) {