netdev - RE: [PATCH 4/4] net: dsa: microchip: avoid hard-codded port count

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Date:   Tue, 27 Aug 2019 21:03:27 +0000
From:   <Tristram.Ha@...rochip.com>
To:     <Razvan.Stefanescu@...rochip.com>
CC:     <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <Razvan.Stefanescu@...rochip.com>, <Woojung.Huh@...rochip.com>,
        <vivien.didelot@...il.com>, <UNGLinuxDriver@...rochip.com>,
        <andrew@...n.ch>, <f.fainelli@...il.com>, <davem@...emloft.net>
Subject: RE: [PATCH 4/4] net: dsa: microchip: avoid hard-codded port count

> Subject: [PATCH 4/4] net: dsa: microchip: avoid hard-codded port count
> 
> Use port_cnt value to disable interrupts on switch reset.
> 
> Signed-off-by: Razvan Stefanescu <razvan.stefanescu@...rochip.com>
> ---
>  drivers/net/dsa/microchip/ksz9477.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/dsa/microchip/ksz9477.c
> b/drivers/net/dsa/microchip/ksz9477.c
> index 187be42de5f1..54fc05595d48 100644
> --- a/drivers/net/dsa/microchip/ksz9477.c
> +++ b/drivers/net/dsa/microchip/ksz9477.c
> @@ -213,7 +213,7 @@ static int ksz9477_reset_switch(struct ksz_device
> *dev)
> 
>  	/* disable interrupts */
>  	ksz_write32(dev, REG_SW_INT_MASK__4, SWITCH_INT_MASK);
> -	ksz_write32(dev, REG_SW_PORT_INT_MASK__4, 0x7F);
> +	ksz_write32(dev, REG_SW_PORT_INT_MASK__4, dev->port_cnt);
>  	ksz_read32(dev, REG_SW_PORT_INT_STATUS__4, &data32);
> 
>  	/* set broadcast storm protection 10% rate */

The register value is a portmap, so using port_cnt may be wrong.

The chip is a 7-port switch.  There is a 6-port variant, but it is okay to write 0x7F.

There is also a 3-port variant which uses a different design.  It is a bit of stretch to use 0x7F on it.

It is more a code readability or correctness than incorrect hardware operation.