ks8851: companion eeprom access through ethtool

Accessing ks8851 companion eeprom permits modifying the ks8851 stored
MAC address.

Example how to change the MAC address using ethtool, to set the
01:23:45:67:89:AB MAC address:
$ echo "0:AB8976452301" | xxd -r > mac.bin
$ sudo ethtool -E eth0 magic 0x8870 offset 2 < mac.bin

Signed-off-by: Sebastien Jan <s-jan@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 114 insertions, 0 deletions

diff --git a/drivers/net/ks8851.c b/drivers/net/ks8851.c
index 3dba57b72ef..b4fb07a6f13 100644
--- a/drivers/net/ks8851.c
+++ b/drivers/net/ks8851.c
@@ -1308,6 +1308,117 @@ static int ks8851_nway_reset(struct net_device *dev)
         return mii_nway_restart(&ks->mii);
 }
 
+static int ks8851_get_eeprom_len(struct net_device *dev)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        return ks->eeprom_size;
+}
+
+static int ks8851_get_eeprom(struct net_device *dev,
+                            struct ethtool_eeprom *eeprom, u8 *bytes)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        u16 *eeprom_buff;
+        int first_word;
+        int last_word;
+        int ret_val = 0;
+        u16 i;
+
+        if (eeprom->len == 0)
+                return -EINVAL;
+
+        if (eeprom->len > ks->eeprom_size)
+                return -EINVAL;
+
+        eeprom->magic = ks8851_rdreg16(ks, KS_CIDER);
+
+        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;
+
+        for (i = 0; i < last_word - first_word + 1; i++)
+                eeprom_buff[i] = ks8851_eeprom_read(dev, first_word + 1);
+
+        /* Device's eeprom is little-endian, word addressable */
+        for (i = 0; i < last_word - first_word + 1; i++)
+                le16_to_cpus(&eeprom_buff[i]);
+
+        memcpy(bytes, (u8 *)eeprom_buff + (eeprom->offset & 1), eeprom->len);
+        kfree(eeprom_buff);
+
+        return ret_val;
+}
+
+static int ks8851_set_eeprom(struct net_device *dev,
+                            struct ethtool_eeprom *eeprom, u8 *bytes)
+{
+        struct ks8851_net *ks = netdev_priv(dev);
+        u16 *eeprom_buff;
+        void *ptr;
+        int max_len;
+        int first_word;
+        int last_word;
+        int ret_val = 0;
+        u16 i;
+
+        if (eeprom->len == 0)
+                return -EOPNOTSUPP;
+
+        if (eeprom->len > ks->eeprom_size)
+                return -EINVAL;
+
+        if (eeprom->magic != ks8851_rdreg16(ks, KS_CIDER))
+                return -EFAULT;
+
+        first_word = eeprom->offset >> 1;
+        last_word = (eeprom->offset + eeprom->len - 1) >> 1;
+        max_len = (last_word - first_word + 1) * 2;
+        eeprom_buff = kmalloc(max_len, GFP_KERNEL);
+        if (!eeprom_buff)
+                return -ENOMEM;
+
+        ptr = (void *)eeprom_buff;
+
+        if (eeprom->offset & 1) {
+                /* need read/modify/write of first changed EEPROM word */
+                /* only the second byte of the word is being modified */
+                eeprom_buff[0] = ks8851_eeprom_read(dev, first_word);
+                ptr++;
+        }
+        if ((eeprom->offset + eeprom->len) & 1)
+                /* need read/modify/write of last changed EEPROM word */
+                /* only the first byte of the word is being modified */
+                eeprom_buff[last_word - first_word] =
+                                        ks8851_eeprom_read(dev, last_word);
+
+
+        /* Device's eeprom is little-endian, word addressable */
+        le16_to_cpus(&eeprom_buff[0]);
+        le16_to_cpus(&eeprom_buff[last_word - first_word]);
+
+        memcpy(ptr, bytes, eeprom->len);
+
+        for (i = 0; i < last_word - first_word + 1; i++)
+                eeprom_buff[i] = cpu_to_le16(eeprom_buff[i]);
+
+        ks8851_eeprom_write(dev, EEPROM_OP_EWEN, 0, 0);
+
+        for (i = 0; i < last_word - first_word + 1; i++) {
+                ks8851_eeprom_write(dev, EEPROM_OP_WRITE, first_word + i,
+                                                        eeprom_buff[i]);
+                mdelay(EEPROM_WRITE_TIME);
+        }
+
+        ks8851_eeprom_write(dev, EEPROM_OP_EWDS, 0, 0);
+
+        kfree(eeprom_buff);
+        return ret_val;
+}
+
 static const struct ethtool_ops ks8851_ethtool_ops = {
         .get_drvinfo    = ks8851_get_drvinfo,
         .get_msglevel   = ks8851_get_msglevel,
@@ -1316,6 +1427,9 @@ static const struct ethtool_ops ks8851_ethtool_ops = {
         .set_settings   = ks8851_set_settings,
         .get_link       = ks8851_get_link,
         .nway_reset     = ks8851_nway_reset,
+        .get_eeprom_len = ks8851_get_eeprom_len,
+        .get_eeprom     = ks8851_get_eeprom,
+        .set_eeprom     = ks8851_set_eeprom,
 };
 
 /* MII interface controls */