6 files changed, 22 insertions, 9 deletions

diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index 68ef48839c04..9f8740ca3f3b 100644
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -9,6 +9,7 @@ that support it.  For example, a given bus might look like this:
      |   |-- class
      |   |-- config
      |   |-- device
+     |   |-- enable
      |   |-- irq
      |   |-- local_cpus
      |   |-- resource
@@ -32,6 +33,7 @@ files, each with their own function.
        class               PCI class (ascii, ro)
        config              PCI config space (binary, rw)
        device              PCI device (ascii, ro)
+       enable              Whether the device is enabled (ascii, rw)
        irq                 IRQ number (ascii, ro)
        local_cpus          nearby CPU mask (cpumask, ro)
        resource            PCI resource host addresses (ascii, ro)
@@ -57,10 +59,19 @@ used to do actual device programming from userspace.  Note that some platforms
 don't support mmapping of certain resources, so be sure to check the return
 value from any attempted mmap.
 
+The 'enable' file provides a counter that indicates how many times the device 
+has been enabled.  If the 'enable' file currently returns '4', and a '1' is
+echoed into it, it will then return '5'.  Echoing a '0' into it will decrease
+the count.  Even when it returns to 0, though, some of the initialisation
+may not be reversed.  
+
 The 'rom' file is special in that it provides read-only access to the device's
 ROM file, if available.  It's disabled by default, however, so applications
 should write the string "1" to the file to enable it before attempting a read
-call, and disable it following the access by writing "0" to the file.
+call, and disable it following the access by writing "0" to the file.  Note
+that the device must be enabled for a rom read to return data succesfully.
+In the event a driver is not bound to the device, it can be enabled using the
+'enable' file, documented above.
 
 Accessing legacy resources through sysfs
 ----------------------------------------
diff --git a/arch/ia64/sn/kernel/io_acpi_init.c b/arch/ia64/sn/kernel/io_acpi_init.c
index c5a214026a77..d0223abbbbd4 100644
--- a/arch/ia64/sn/kernel/io_acpi_init.c
+++ b/arch/ia64/sn/kernel/io_acpi_init.c
@@ -443,7 +443,7 @@ sn_acpi_slot_fixup(struct pci_dev *dev)
                 size = pci_resource_len(dev, PCI_ROM_RESOURCE);
                 addr = ioremap(pcidev_info->pdi_pio_mapped_addr[PCI_ROM_RESOURCE],
                                size);
-                image_size = pci_get_rom_size(addr, size);
+                image_size = pci_get_rom_size(dev, addr, size);
                 dev->resource[PCI_ROM_RESOURCE].start = (unsigned long) addr;
                 dev->resource[PCI_ROM_RESOURCE].end =
                                         (unsigned long) addr + image_size - 1;
diff --git a/arch/ia64/sn/kernel/io_init.c b/arch/ia64/sn/kernel/io_init.c
index 4e1801bad83a..e2eb2da60f96 100644
--- a/arch/ia64/sn/kernel/io_init.c
+++ b/arch/ia64/sn/kernel/io_init.c
@@ -269,7 +269,7 @@ sn_io_slot_fixup(struct pci_dev *dev)
 
                         rom = ioremap(pci_resource_start(dev, PCI_ROM_RESOURCE),
                                       size + 1);
-                        image_size = pci_get_rom_size(rom, size + 1);
+                        image_size = pci_get_rom_size(dev, rom, size + 1);
                         dev->resource[PCI_ROM_RESOURCE].end =
                                 dev->resource[PCI_ROM_RESOURCE].start +
                                 image_size - 1;
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index db7ec14fa719..dfc4e0ddf241 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -768,8 +768,8 @@ pci_read_rom(struct kobject *kobj, struct bin_attribute *bin_attr,
                 return -EINVAL;
         
         rom = pci_map_rom(pdev, &size); /* size starts out as PCI window size */
-        if (!rom)
-                return 0;
+        if (!rom || !size)
+                return -EIO;
                 
         if (off >= size)
                 count = 0;
diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c
index 132a78159b60..29cbe47f219f 100644
--- a/drivers/pci/rom.c
+++ b/drivers/pci/rom.c
@@ -63,7 +63,7 @@ void pci_disable_rom(struct pci_dev *pdev)
  * The PCI window size could be much larger than the
  * actual image size.
  */
-size_t pci_get_rom_size(void __iomem *rom, size_t size)
+size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size)
 {
         void __iomem *image;
         int last_image;
@@ -72,8 +72,10 @@ size_t pci_get_rom_size(void __iomem *rom, size_t size)
         do {
                 void __iomem *pds;
                 /* Standard PCI ROMs start out with these bytes 55 AA */
-                if (readb(image) != 0x55)
+                if (readb(image) != 0x55) {
+                        dev_err(&pdev->dev, "Invalid ROM contents\n");
                         break;
+                }
                 if (readb(image + 1) != 0xAA)
                         break;
                 /* get the PCI data structure and check its signature */
@@ -159,7 +161,7 @@ void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
          * size is much larger than the actual size of the ROM.
          * True size is important if the ROM is going to be copied.
          */
-        *size = pci_get_rom_size(rom, *size);
+        *size = pci_get_rom_size(pdev, rom, *size);
         return rom;
 }
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 48890cf3f96e..7bd624bfdcfd 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -684,7 +684,7 @@ int pci_enable_rom(struct pci_dev *pdev);
 void pci_disable_rom(struct pci_dev *pdev);
 void __iomem __must_check *pci_map_rom(struct pci_dev *pdev, size_t *size);
 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom);
-size_t pci_get_rom_size(void __iomem *rom, size_t size);
+size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size);
 
 /* Power management related routines */
 int pci_save_state(struct pci_dev *dev);