asix: Rework reading from EEPROM

The current code for reading the EEPROM via ethtool in the asix
driver has a few issues. It cannot handle odd length values
(accesses must be aligned at 16 bit boundaries) and interprets the
offset provided by ethtool as 16 bit word offset instead as byte offset.

The new code for asix_get_eeprom() introduced by this patch is
modeled after the code in
drivers/net/ethernet/atheros/atl1e/atl1e_ethtool.c
and provides read access to the entire EEPROM with arbitrary
offsets and lengths.

Signed-off-by: Christian Riesch <christian.riesch@omicron.at>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 17 deletions

diff --git a/drivers/net/usb/asix_common.c b/drivers/net/usb/asix_common.c
index 336f75567091..0b5b2d328a56 100644
--- a/drivers/net/usb/asix_common.c
+++ b/drivers/net/usb/asix_common.c
@@ -478,46 +478,51 @@ int asix_set_wol(struct net_device *net, struct ethtool_wolinfo *wolinfo)
 
 int asix_get_eeprom_len(struct net_device *net)
 {
-        struct usbnet *dev = netdev_priv(net);
-        struct asix_data *data = (struct asix_data *)&dev->data;
-
-        return data->eeprom_len;
+        return AX_EEPROM_LEN;
 }
 
 int asix_get_eeprom(struct net_device *net, struct ethtool_eeprom *eeprom,
                     u8 *data)
 {
         struct usbnet *dev = netdev_priv(net);
-        __le16 *ebuf = (__le16 *)data;
+        u16 *eeprom_buff;
+        int first_word, last_word;
         int i;
 
-        /* Crude hack to ensure that we don't overwrite memory
-         * if an odd length is supplied
-         */
-        if (eeprom->len % 2)
+        if (eeprom->len == 0)
                 return -EINVAL;
 
         eeprom->magic = AX_EEPROM_MAGIC;
 
+        first_word = eeprom->offset >> 1;
+        last_word = (eeprom->offset + eeprom->len - 1) >> 1;
+
+        eeprom_buff = kmalloc(sizeof(u16) * (last_word - first_word + 1),
+                              GFP_KERNEL);
+        if (!eeprom_buff)
+                return -ENOMEM;
+
         /* ax8817x returns 2 bytes from eeprom on read */
-        for (i=0; i < eeprom->len / 2; i++) {
-                if (asix_read_cmd(dev, AX_CMD_READ_EEPROM,
-                        eeprom->offset + i, 0, 2, &ebuf[i]) < 0)
-                        return -EINVAL;
+        for (i = first_word; i <= last_word; i++) {
+                if (asix_read_cmd(dev, AX_CMD_READ_EEPROM, i, 0, 2,
+                                  &(eeprom_buff[i - first_word])) < 0) {
+                        kfree(eeprom_buff);
+                        return -EIO;
+                }
         }
+
+        memcpy(data, (u8 *)eeprom_buff + (eeprom->offset & 1), eeprom->len);
+        kfree(eeprom_buff);
         return 0;
 }
 
 void asix_get_drvinfo(struct net_device *net, struct ethtool_drvinfo *info)
 {
-        struct usbnet *dev = netdev_priv(net);
-        struct asix_data *data = (struct asix_data *)&dev->data;
-
         /* Inherit standard device info */
         usbnet_get_drvinfo(net, info);
         strncpy (info->driver, DRIVER_NAME, sizeof info->driver);
         strncpy (info->version, DRIVER_VERSION, sizeof info->version);
-        info->eedump_len = data->eeprom_len;
+        info->eedump_len = AX_EEPROM_LEN;
 }
 
 int asix_set_mac_address(struct net_device *net, void *p)