[PATCH net 0/2] net: systemport: misc fixes

[PATCH net 0/2] net: systemport: misc fixes

[Florian Fainelli]

Hi David,

Here are two small fixes for SYSTEMPORT targeted at the 'net' tree, thanks!

Florian Fainelli (2):
  net: systemport: do not clear IFF_MULTICAST flag
  net: systemport: fix UniMAC reset logic

 drivers/net/ethernet/broadcom/bcmsysport.c | 39 +++++++-----------------------
 1 file changed, 9 insertions(+), 30 deletions(-)

-- 
1.9.1

[PATCH net 1/2] net: systemport: do not clear IFF_MULTICAST flag

[Florian Fainelli]

The SYSTEMPORT Ethernet MAC supports multicast just fine, it just lacks
any sort of Unicast/Broadcast/Multicasting filtering at the Ethernet MAC
level since that is handled by the front end Ethernet switch, but that
is properly handled by bcm_sysport_set_rx_mode().

Some user-space applications might be relying on the presence of this
flag to prevent using multicast sockets, this also prevents that
interface from joining the IPv6 all-router mcast group.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/ethernet/broadcom/bcmsysport.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
index 141160ef249a..f6bccd847ee6 100644
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -1589,12 +1589,6 @@ static int bcm_sysport_probe(struct platform_device *pdev)
 	BUILD_BUG_ON(sizeof(struct bcm_tsb) != 8);
 	dev->needed_headroom += sizeof(struct bcm_tsb);
 
-	/* We are interfaced to a switch which handles the multicast
-	 * filtering for us, so we do not support programming any
-	 * multicast hash table in this Ethernet MAC.
-	 */
-	dev->flags &= ~IFF_MULTICAST;
-
 	/* libphy will adjust the link state accordingly */
 	netif_carrier_off(dev);
 
-- 
1.9.1

[PATCH net 2/2] net: systemport: fix UniMAC reset logic

[Florian Fainelli]

The UniMAC CMD_SW_RESET bit is not a self-clearing bit, so we need to
assert it, wait a bit and clear it manually. As a result, umac_reset()
is updated not to return any value.

By setting CMD_SW_RESET and only that bit, we were also clearing the
other 31 bits, overriding the hardware reset defaults which are
correctly set on purpose.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/ethernet/broadcom/bcmsysport.c | 33 ++++++++----------------------
 1 file changed, 9 insertions(+), 24 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
index f6bccd847ee6..d31f7d239064 100644
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -1254,28 +1254,17 @@ static inline void umac_enable_set(struct bcm_sysport_priv *priv,
 		usleep_range(1000, 2000);
 }
 
-static inline int umac_reset(struct bcm_sysport_priv *priv)
+static inline void umac_reset(struct bcm_sysport_priv *priv)
 {
-	unsigned int timeout = 0;
 	u32 reg;
-	int ret = 0;
-
-	umac_writel(priv, 0, UMAC_CMD);
-	while (timeout++ < 1000) {
-		reg = umac_readl(priv, UMAC_CMD);
-		if (!(reg & CMD_SW_RESET))
-			break;
-
-		udelay(1);
-	}
-
-	if (timeout == 1000) {
-		dev_err(&priv->pdev->dev,
-			"timeout waiting for MAC to come out of reset\n");
-		ret = -ETIMEDOUT;
-	}
 
-	return ret;
+	reg = umac_readl(priv, UMAC_CMD);
+	reg |= CMD_SW_RESET;
+	umac_writel(priv, reg, UMAC_CMD);
+	udelay(10);
+	reg = umac_readl(priv, UMAC_CMD);
+	reg &= ~CMD_SW_RESET;
+	umac_writel(priv, reg, UMAC_CMD);
 }
 
 static void umac_set_hw_addr(struct bcm_sysport_priv *priv,
@@ -1303,11 +1292,7 @@ static int bcm_sysport_open(struct net_device *dev)
 	int ret;
 
 	/* Reset UniMAC */
-	ret = umac_reset(priv);
-	if (ret) {
-		netdev_err(dev, "UniMAC reset failed\n");
-		return ret;
-	}
+	umac_reset(priv);
 
 	/* Flush TX and RX FIFOs at TOPCTRL level */
 	topctrl_flush(priv);
-- 
1.9.1

Re: [PATCH net 2/2] net: systemport: fix UniMAC reset logic

[Sergei Shtylyov]

Hello.

On 06/21/2014 12:01 AM, Florian Fainelli wrote:

> The UniMAC CMD_SW_RESET bit is not a self-clearing bit, so we need to
> assert it, wait a bit and clear it manually. As a result, umac_reset()
> is updated not to return any value.

> By setting CMD_SW_RESET and only that bit, we were also clearing the

    I wonder where you were setting this bit before -- the only umac_writel() 
there was wrote 0 to UMAC_CMD...

> other 31 bits, overriding the hardware reset defaults which are
> correctly set on purpose.

> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
>   drivers/net/ethernet/broadcom/bcmsysport.c | 33 ++++++++----------------------
>   1 file changed, 9 insertions(+), 24 deletions(-)

> diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
> index f6bccd847ee6..d31f7d239064 100644
> --- a/drivers/net/ethernet/broadcom/bcmsysport.c
> +++ b/drivers/net/ethernet/broadcom/bcmsysport.c
> @@ -1254,28 +1254,17 @@ static inline void umac_enable_set(struct bcm_sysport_priv *priv,
>   		usleep_range(1000, 2000);
>   }
>
> -static inline int umac_reset(struct bcm_sysport_priv *priv)
> +static inline void umac_reset(struct bcm_sysport_priv *priv)
>   {
> -	unsigned int timeout = 0;
>   	u32 reg;
> -	int ret = 0;
> -
> -	umac_writel(priv, 0, UMAC_CMD);
> -	while (timeout++ < 1000) {
> -		reg = umac_readl(priv, UMAC_CMD);
> -		if (!(reg & CMD_SW_RESET))
> -			break;
> -
> -		udelay(1);
> -	}
> -
> -	if (timeout == 1000) {
> -		dev_err(&priv->pdev->dev,
> -			"timeout waiting for MAC to come out of reset\n");
> -		ret = -ETIMEDOUT;
> -	}
>
> -	return ret;
> +	reg = umac_readl(priv, UMAC_CMD);
> +	reg |= CMD_SW_RESET;
> +	umac_writel(priv, reg, UMAC_CMD);
> +	udelay(10);
> +	reg = umac_readl(priv, UMAC_CMD);
> +	reg &= ~CMD_SW_RESET;
> +	umac_writel(priv, reg, UMAC_CMD);
>   }
>
>   static void umac_set_hw_addr(struct bcm_sysport_priv *priv,
[...]

WBR, Sergei

Re: [PATCH net 2/2] net: systemport: fix UniMAC reset logic

[David Miller]

From: Florian Fainelli <f.fainelli@gmail.com>
Date: Fri, 20 Jun 2014 13:01:40 -0700

> The UniMAC CMD_SW_RESET bit is not a self-clearing bit, so we need to
> assert it, wait a bit and clear it manually. As a result, umac_reset()
> is updated not to return any value.
> 
> By setting CMD_SW_RESET and only that bit, we were also clearing the
> other 31 bits, overriding the hardware reset defaults which are
> correctly set on purpose.
> 
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

I agree with Sergei, this is really suspicious that the existing code
never wrote the sw reset bit into the register at all, it just writes
a zero.

And you don't mention this at all in this commit message.

If I were to guess, I would fathom that the sequence was partially
copied from the other broadcom driver, the genet one.  There it
issues CMD_SW_RESET by first clearing the entire regiser to zero,
then writing CMD_SW_RESET, and then polling for that bit to clear.

I'm assuming that is being done for a good reason, and I'd like
you to make sure that same reason does not apply here.

Thanks.

Re: [PATCH net 2/2] net: systemport: fix UniMAC reset logic

[Florian Fainelli]

2014-06-24 16:12 GMT-07:00 David Miller <davem@davemloft.net>:
> From: Florian Fainelli <f.fainelli@gmail.com>
> Date: Fri, 20 Jun 2014 13:01:40 -0700
>
>> The UniMAC CMD_SW_RESET bit is not a self-clearing bit, so we need to
>> assert it, wait a bit and clear it manually. As a result, umac_reset()
>> is updated not to return any value.
>>
>> By setting CMD_SW_RESET and only that bit, we were also clearing the
>> other 31 bits, overriding the hardware reset defaults which are
>> correctly set on purpose.
>>
>> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
>
> I agree with Sergei, this is really suspicious that the existing code
> never wrote the sw reset bit into the register at all, it just writes
> a zero.
>
> And you don't mention this at all in this commit message.
>
> If I were to guess, I would fathom that the sequence was partially
> copied from the other broadcom driver, the genet one.  There it
> issues CMD_SW_RESET by first clearing the entire regiser to zero,
> then writing CMD_SW_RESET, and then polling for that bit to clear.
>
> I'm assuming that is being done for a good reason, and I'd like
> you to make sure that same reason does not apply here.

I'll resubmit with a proper explanation, thanks.
-- 
Florian