[PATCHv2 net-next] net: fec: Ensure clocks are enabled while using mdio bus

[PATCHv2 net-next] net: fec: Ensure clocks are enabled while using mdio bus

[Andrew Lunn]

When a switch is attached to the mdio bus, the mdio bus can be used
while the interface is not open. If the IPG clock are not enabled,
MDIO reads/writes will simply time out. So enable the clock before
starting a transaction, and disable it afterwards. The CCF performs
reference counting so the clock will only be disabled if there are no
other users.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
---
v2:
  Only enable/disable the IPG clock.

drivers/net/ethernet/freescale/fec_main.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index bf4cf3fbb5f2..2b8a043a573c 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -65,6 +65,7 @@
 
 static void set_multicast_list(struct net_device *ndev);
 static void fec_enet_itr_coal_init(struct net_device *ndev);
+static int fec_enet_clk_enable(struct net_device *ndev, bool enable);
 
 #define DRIVER_NAME	"fec"
 
@@ -1764,6 +1765,11 @@ static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 {
 	struct fec_enet_private *fep = bus->priv;
 	unsigned long time_left;
+	int ret;
+
+	ret = clk_prepare_enable(fep->clk_ipg);
+	if (ret)
+		return 0xffff;
 
 	fep->mii_timeout = 0;
 	init_completion(&fep->mdio_done);
@@ -1779,11 +1785,14 @@ static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 	if (time_left == 0) {
 		fep->mii_timeout = 1;
 		netdev_err(fep->netdev, "MDIO read timeout\n");
+		clk_disable_unprepare(fep->clk_ipg);
 		return -ETIMEDOUT;
 	}
 
-	/* return value */
-	return FEC_MMFR_DATA(readl(fep->hwp + FEC_MII_DATA));
+	ret = FEC_MMFR_DATA(readl(fep->hwp + FEC_MII_DATA));
+	clk_disable_unprepare(fep->clk_ipg);
+
+	return ret;
 }
 
 static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
@@ -1791,10 +1800,15 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 {
 	struct fec_enet_private *fep = bus->priv;
 	unsigned long time_left;
+	int ret;
 
 	fep->mii_timeout = 0;
 	init_completion(&fep->mdio_done);
 
+	ret = clk_prepare_enable(fep->clk_ipg);
+	if (ret)
+		return ret;
+
 	/* start a write op */
 	writel(FEC_MMFR_ST | FEC_MMFR_OP_WRITE |
 		FEC_MMFR_PA(mii_id) | FEC_MMFR_RA(regnum) |
@@ -1807,9 +1821,12 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 	if (time_left == 0) {
 		fep->mii_timeout = 1;
 		netdev_err(fep->netdev, "MDIO write timeout\n");
+		clk_disable_unprepare(fep->clk_ipg);
 		return -ETIMEDOUT;
 	}
 
+	clk_disable_unprepare(fep->clk_ipg);
+
 	return 0;
 }
 
-- 
2.1.4

Re: [PATCHv2 net-next] net: fec: Ensure clocks are enabled while using mdio bus

[Fabio Estevam]

On Sat, Jun 20, 2015 at 1:15 PM, Andrew Lunn <andrew@lunn.ch> wrote:

> @@ -1764,6 +1765,11 @@ static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
>  {
>         struct fec_enet_private *fep = bus->priv;
>         unsigned long time_left;
> +       int ret;
> +
> +       ret = clk_prepare_enable(fep->clk_ipg);
> +       if (ret)
> +               return 0xffff;

Why don`t you return ret instead?

Re: [PATCHv2 net-next] net: fec: Ensure clocks are enabled while using mdio bus

[Andrew Lunn]

On Sat, Jun 20, 2015 at 02:47:20PM -0300, Fabio Estevam wrote:
> On Sat, Jun 20, 2015 at 1:15 PM, Andrew Lunn <andrew@lunn.ch> wrote:
> 
> > @@ -1764,6 +1765,11 @@ static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
> >  {
> >         struct fec_enet_private *fep = bus->priv;
> >         unsigned long time_left;
> > +       int ret;
> > +
> > +       ret = clk_prepare_enable(fep->clk_ipg);
> > +       if (ret)
> > +               return 0xffff;
> 
> Why don`t you return ret instead?

ret would also work.

v3 to follow soon.

   Andrew

Re: [PATCHv2 net-next] net: fec: Ensure clocks are enabled while using mdio bus

[Florian Fainelli]

Le 06/20/15 09:15, Andrew Lunn a écrit :
> When a switch is attached to the mdio bus, the mdio bus can be used
> while the interface is not open. If the IPG clock are not enabled,
> MDIO reads/writes will simply time out. So enable the clock before
> starting a transaction, and disable it afterwards. The CCF performs
> reference counting so the clock will only be disabled if there are no
> other users.
> 
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> ---
> v2:
>   Only enable/disable the IPG clock.
> 
> drivers/net/ethernet/freescale/fec_main.c | 21 +++++++++++++++++++--
>  1 file changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> index bf4cf3fbb5f2..2b8a043a573c 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -65,6 +65,7 @@
>  
>  static void set_multicast_list(struct net_device *ndev);
>  static void fec_enet_itr_coal_init(struct net_device *ndev);
> +static int fec_enet_clk_enable(struct net_device *ndev, bool enable);

You do not seem to be using this, unrelated change?
-- 
Florian

Re: [PATCHv2 net-next] net: fec: Ensure clocks are enabled while using mdio bus

[Andrew Lunn]

On Sat, Jun 20, 2015 at 06:01:33PM -0700, Florian Fainelli wrote:
> Le 06/20/15 09:15, Andrew Lunn a écrit :
> > When a switch is attached to the mdio bus, the mdio bus can be used
> > while the interface is not open. If the IPG clock are not enabled,
> > MDIO reads/writes will simply time out. So enable the clock before
> > starting a transaction, and disable it afterwards. The CCF performs
> > reference counting so the clock will only be disabled if there are no
> > other users.
> > 
> > Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> > ---
> > v2:
> >   Only enable/disable the IPG clock.
> > 
> > drivers/net/ethernet/freescale/fec_main.c | 21 +++++++++++++++++++--
> >  1 file changed, 19 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> > index bf4cf3fbb5f2..2b8a043a573c 100644
> > --- a/drivers/net/ethernet/freescale/fec_main.c
> > +++ b/drivers/net/ethernet/freescale/fec_main.c
> > @@ -65,6 +65,7 @@
> >  
> >  static void set_multicast_list(struct net_device *ndev);
> >  static void fec_enet_itr_coal_init(struct net_device *ndev);
> > +static int fec_enet_clk_enable(struct net_device *ndev, bool enable);
> 
> You do not seem to be using this, unrelated change?

Hi Florian

Left over from v1, where i did call this function to enable/disable
the clocks. It can be removed now that i use the common clock
framework directly to enable only a single clock.

	  Andrew