linux-kernel - Re: [PATCH 2/3] usbnet: add a mutex around phy register access

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Date:	Wed, 27 Sep 2006 15:33:04 -0400
From:	dhollis@...ehollis.com
To:	Arnd Bergmann <arnd@...db.de>
Cc:	David Brownell <david-b@...bell.net>,
	linux-usb-devel@...ts.sourceforge.net, support@...chip.com,
	dbrownell@...rs.sourceforge.net, linux-kernel@...r.kernel.org,
	Michael Helmling <supermihi@....de>
Subject: Re: [PATCH 2/3] usbnet: add a mutex around phy register access

Quoting Arnd Bergmann <arnd@...db.de>:

> 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.
>
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
>

Acked-by: David Hollis <dhollis@...ehollis.com>


> ---
> Index: linux-cg/drivers/usb/net/asix.c
> ===================================================================
> --- linux-cg.orig/drivers/usb/net/asix.c	2006-09-17 00:10:53.000000000 +0200
> +++ linux-cg/drivers/usb/net/asix.c	2006-09-17 00:18:08.000000000 +0200
> @@ -328,10 +328,12 @@
>  	struct usbnet *dev = netdev_priv(netdev);
>  	u16 res;
>
> +	mutex_lock(&dev->phy_mutex);
>  	asix_set_sw_mii(dev);
>  	asix_read_cmd(dev, AX_CMD_READ_MII_REG, phy_id,
>  				(__u16)loc, 2, (u16 *)&res);
>  	asix_set_hw_mii(dev);
> +	mutex_unlock(&dev->phy_mutex);
>
>  	return res & 0xffff;
>  }
> @@ -348,10 +350,12 @@
>  	struct usbnet *dev = netdev_priv(netdev);
>  	u16 res = val;
>
> +	mutex_lock(&dev->phy_mutex);
>  	asix_set_sw_mii(dev);
>  	asix_write_cmd(dev, AX_CMD_WRITE_MII_REG, phy_id,
>  				(__u16)loc, 2, (u16 *)&res);
>  	asix_set_hw_mii(dev);
> +	mutex_unlock(&dev->phy_mutex);
>  }
>
>  /* same as above, but converts new value to le16 byte order before   
> writing */
> Index: linux-cg/drivers/usb/net/usbnet.c
> ===================================================================
> --- linux-cg.orig/drivers/usb/net/usbnet.c	2006-09-17   
> 00:10:53.000000000 +0200
> +++ linux-cg/drivers/usb/net/usbnet.c	2006-09-17 00:18:08.000000000 +0200
> @@ -1112,6 +1112,7 @@
>  	dev->delay.function = usbnet_bh;
>  	dev->delay.data = (unsigned long) dev;
>  	init_timer (&dev->delay);
> +	mutex_init (&dev->phy_mutex);
>
>  	SET_MODULE_OWNER (net);
>  	dev->net = net;
> Index: linux-cg/drivers/usb/net/usbnet.h
> ===================================================================
> --- linux-cg.orig/drivers/usb/net/usbnet.h	2006-09-17   
> 00:10:53.000000000 +0200
> +++ linux-cg/drivers/usb/net/usbnet.h	2006-09-17 00:18:08.000000000 +0200
> @@ -30,6 +30,7 @@
>  	struct usb_device	*udev;
>  	struct driver_info	*driver_info;
>  	wait_queue_head_t	*wait;
> +	struct mutex		phy_mutex;
>
>  	/* i/o info: pipes etc */
>  	unsigned		in, out;
> Index: linux-cg/drivers/usb/net/mcs7830.c
> ===================================================================
> --- linux-cg.orig/drivers/usb/net/mcs7830.c	2006-09-17   
> 00:10:53.000000000 +0200
> +++ linux-cg/drivers/usb/net/mcs7830.c	2006-09-17 00:18:08.000000000 +0200
> @@ -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;
>  }
>
>
>



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