[PATCH net-next 1/2] ethtool: Add set regs -D option support

[Saeed Mahameed]

From: Gal Pressman <g...@mellanox.com>

Currently ethtool only allows us to get device registers, in this patch
we extend this functionality to also set device registers.
ethtool -D DEVNAME [ file FILENAME ] is used to set registers in
the device using vendor specific binary registers data provided via
stdin/file. Changes made by this option can be queried using get
regs -d flag.

Example:
$ ethtool -D eth1 file /tmp/mlx5_regs

Signed-off-by: Gal Pressman <g...@mellanox.com>
Signed-off-by: Dmitry Teif <di...@mellanox.com>
CC: John W. Linville <linvi...@tuxdriver.com>
Signed-off-by: Saeed Mahameed <sae...@mellanox.com>
---
 include/linux/ethtool.h      |  1 +
 include/uapi/linux/ethtool.h |  1 +
 net/core/ethtool.c           | 31 +++++++++++++++++++++++++++++++
 3 files changed, 33 insertions(+)

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 9ded8c6..c9f5d37 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -305,6 +305,7 @@ struct ethtool_ops {
        void    (*get_drvinfo)(struct net_device *, struct ethtool_drvinfo *);
        int     (*get_regs_len)(struct net_device *);
        void    (*get_regs)(struct net_device *, struct ethtool_regs *, void *);
+       int     (*set_regs)(struct net_device *, struct ethtool_regs *, u8 *);
        void    (*get_wol)(struct net_device *, struct ethtool_wolinfo *);
        int     (*set_wol)(struct net_device *, struct ethtool_wolinfo *);
        u32     (*get_msglevel)(struct net_device *);
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index f0db778..f81c6fd 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -1330,6 +1330,7 @@ struct ethtool_per_queue_op {
 #define ETHTOOL_SLINKSETTINGS  0x0000004d /* Set ethtool_link_settings */
 #define ETHTOOL_PHY_GTUNABLE   0x0000004e /* Get PHY tunable configuration */
 #define ETHTOOL_PHY_STUNABLE   0x0000004f /* Set PHY tunable configuration */
+#define ETHTOOL_SREGS          0x00000050 /* Set NIC registers */
 
 /* compatibility with older code */
 #define SPARC_ETH_GSET         ETHTOOL_GSET
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index e23766c..5548565 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -1424,6 +1424,34 @@ static int ethtool_get_regs(struct net_device *dev, char 
__user *useraddr)
        return ret;
 }
 
+static int ethtool_set_regs(struct net_device *dev, char __user *useraddr)
+{
+       void __user *userbuf = useraddr + offsetof(struct ethtool_regs, data);
+       const struct ethtool_ops *ops = dev->ethtool_ops;
+       struct ethtool_regs regs;
+       int ret = 0;
+       u8 *data;
+
+       if (!ops->set_regs || !ops->get_regs_len)
+               return -EOPNOTSUPP;
+       if (copy_from_user(&regs, useraddr, sizeof(regs)))
+               return -EFAULT;
+
+       data = kmalloc(PAGE_SIZE, GFP_USER);
+       if (!data)
+               return -ENOMEM;
+
+       ret = -EFAULT;
+       if (copy_from_user(data, userbuf, regs.len))
+               goto out;
+
+       ret = ops->set_regs(dev, &regs, data);
+
+out:
+       kfree(data);
+       return ret;
+}
+
 static int ethtool_reset(struct net_device *dev, char __user *useraddr)
 {
        struct ethtool_value reset;
@@ -2597,6 +2625,9 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
        case ETHTOOL_GREGS:
                rc = ethtool_get_regs(dev, useraddr);
                break;
+       case ETHTOOL_SREGS:
+               rc = ethtool_set_regs(dev, useraddr);
+               break;
        case ETHTOOL_GWOL:
                rc = ethtool_get_wol(dev, useraddr);
                break;
-- 
2.7.4