usbnet: add a mutex around phy register access
When working on the mcs7830, I noticed the need for a mutex in its
mdio_read/mdio_write functions. A related problem seems to be present
in the asix driver in the respective functions.
This introduces a mutex in the common usbnet driver and uses it
from the two hardware specific drivers.
Acked-by: David Hollis <dhollis@davehollis.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/net/mcs7830.c b/drivers/usb/net/mcs7830.c
index 23a8066..6240b97 100644
--- a/drivers/usb/net/mcs7830.c
+++ b/drivers/usb/net/mcs7830.c
@@ -184,6 +184,7 @@
HIF_REG_PHY_CMD2_PEND_FLAG_BIT | index,
};
+ mutex_lock(&dev->phy_mutex);
/* write the MII command */
ret = mcs7830_set_reg(dev, HIF_REG_PHY_CMD1, 2, cmd);
if (ret < 0)
@@ -208,6 +209,7 @@
dev_dbg(&dev->udev->dev, "read PHY reg %02x: %04x (%d tries)\n",
index, val, i);
out:
+ mutex_unlock(&dev->phy_mutex);
return ret;
}
@@ -222,6 +224,8 @@
HIF_REG_PHY_CMD2_PEND_FLAG_BIT | (index & 0x1F),
};
+ mutex_lock(&dev->phy_mutex);
+
/* write the new register contents */
le_val = cpu_to_le16(val);
ret = mcs7830_set_reg(dev, HIF_REG_PHY_DATA, 2, &le_val);
@@ -248,6 +252,7 @@
dev_dbg(&dev->udev->dev, "write PHY reg %02x: %04x (%d tries)\n",
index, val, i);
out:
+ mutex_unlock(&dev->phy_mutex);
return ret;
}