[PATCH] PCI: fix up word-aligned 16-bit PCI config access through sysfs

This patch adds the possibility to do word-aligned 16-bit atomic PCI
configuration space accesses via the sysfs PCI interface. As a result, problems
with Emulex LFPC on IBM PowerPC64 are fixed.

Patch is present in SLES 9 SP1.

Signed-off-by: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index d57ae71d32b1dd42a77689498e691263d263c3e4..8568b207f18927f4d4cc23006ff2edf07dc932be 100644 (file)
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -91,6 +91,7 @@ pci_read_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
        struct pci_dev *dev = to_pci_dev(container_of(kobj,struct device,kobj));
        unsigned int size = 64;
        loff_t init_off = off;
+       u8 *data = (u8*) buf;
 
        /* Several chips lock up trying to read undefined config space */
        if (capable(CAP_SYS_ADMIN)) {
@@ -108,30 +109,47 @@ pci_read_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
                size = count;
        }
 
-       while (off & 3) {
-               unsigned char val;
+       if ((off & 1) && size) {
+               u8 val;
                pci_read_config_byte(dev, off, &val);
-               buf[off - init_off] = val;
+               data[off - init_off] = val;
                off++;
-               if (--size == 0)
-                       break;
+               size--;
+       }
+
+       if ((off & 3) && size > 2) {
+               u16 val;
+               pci_read_config_word(dev, off, &val);
+               data[off - init_off] = val & 0xff;
+               data[off - init_off + 1] = (val >> 8) & 0xff;
+               off += 2;
+               size -= 2;
        }
 
        while (size > 3) {
-               unsigned int val;
+               u32 val;
                pci_read_config_dword(dev, off, &val);
-               buf[off - init_off] = val & 0xff;
-               buf[off - init_off + 1] = (val >> 8) & 0xff;
-               buf[off - init_off + 2] = (val >> 16) & 0xff;
-               buf[off - init_off + 3] = (val >> 24) & 0xff;
+               data[off - init_off] = val & 0xff;
+               data[off - init_off + 1] = (val >> 8) & 0xff;
+               data[off - init_off + 2] = (val >> 16) & 0xff;
+               data[off - init_off + 3] = (val >> 24) & 0xff;
                off += 4;
                size -= 4;
        }
 
-       while (size > 0) {
-               unsigned char val;
+       if (size >= 2) {
+               u16 val;
+               pci_read_config_word(dev, off, &val);
+               data[off - init_off] = val & 0xff;
+               data[off - init_off + 1] = (val >> 8) & 0xff;
+               off += 2;
+               size -= 2;
+       }
+
+       if (size > 0) {
+               u8 val;
                pci_read_config_byte(dev, off, &val);
-               buf[off - init_off] = val;
+               data[off - init_off] = val;
                off++;
                --size;
        }
@@ -145,6 +163,7 @@ pci_write_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
        struct pci_dev *dev = to_pci_dev(container_of(kobj,struct device,kobj));
        unsigned int size = count;
        loff_t init_off = off;
+       u8 *data = (u8*) buf;
 
        if (off > dev->cfg_size)
                return 0;
@@ -152,26 +171,41 @@ pci_write_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
                size = dev->cfg_size - off;
                count = size;
        }
-
-       while (off & 3) {
-               pci_write_config_byte(dev, off, buf[off - init_off]);
+       
+       if ((off & 1) && size) {
+               pci_write_config_byte(dev, off, data[off - init_off]);
                off++;
-               if (--size == 0)
-                       break;
+               size--;
        }
+       
+       if ((off & 3) && size > 2) {
+               u16 val = data[off - init_off];
+               val |= (u16) data[off - init_off + 1] << 8;
+                pci_write_config_word(dev, off, val);
+                off += 2;
+                size -= 2;
+        }
 
        while (size > 3) {
-               unsigned int val = buf[off - init_off];
-               val |= (unsigned int) buf[off - init_off + 1] << 8;
-               val |= (unsigned int) buf[off - init_off + 2] << 16;
-               val |= (unsigned int) buf[off - init_off + 3] << 24;
+               u32 val = data[off - init_off];
+               val |= (u32) data[off - init_off + 1] << 8;
+               val |= (u32) data[off - init_off + 2] << 16;
+               val |= (u32) data[off - init_off + 3] << 24;
                pci_write_config_dword(dev, off, val);
                off += 4;
                size -= 4;
        }
+       
+       if (size >= 2) {
+               u16 val = data[off - init_off];
+               val |= (u16) data[off - init_off + 1] << 8;
+               pci_write_config_word(dev, off, val);
+               off += 2;
+               size -= 2;
+       }
 
-       while (size > 0) {
-               pci_write_config_byte(dev, off, buf[off - init_off]);
+       if (size) {
+               pci_write_config_byte(dev, off, data[off - init_off]);
                off++;
                --size;
        }