[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>

1 files changed, 58 insertions, 24 deletions

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index d57ae71d32b..8568b207f18 100644
--- 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;
         }