[net,v2] net: dsa: mv88e6xxx: Preserve priority when setting CPU port.

The 6390 family uses an extended register to set the port connected to
the CPU. The lower 5 bits indicate the port, the upper three bits are
the priority of the frames as they pass through the switch, what
egress queue they should use, etc. Since frames being set to the CPU
are typically management frames, BPDU, IGMP, ARP, etc set the priority
to 7, the reset default, and the highest.

Fixes: 33641994a676 ("net: dsa: mv88e6xxx: Monitor and Management tables")
Signed-off-by: Andrew Lunn <andrew@lunn.ch>

---
v2: Fix a couple of spelling errors.
---
 drivers/net/dsa/mv88e6xxx/global1.c | 5 +++++
 drivers/net/dsa/mv88e6xxx/global1.h | 1 +
 2 files changed, 6 insertions(+)

Tested-by: Chris Healy <cphealy@gmail.com>

On Sat, Jan 4, 2020 at 2:14 PM Andrew Lunn <andrew@lunn.ch> wrote:
>
> The 6390 family uses an extended register to set the port connected to
> the CPU. The lower 5 bits indicate the port, the upper three bits are
> the priority of the frames as they pass through the switch, what
> egress queue they should use, etc. Since frames being set to the CPU
> are typically management frames, BPDU, IGMP, ARP, etc set the priority
> to 7, the reset default, and the highest.
>
> Fixes: 33641994a676 ("net: dsa: mv88e6xxx: Monitor and Management tables")
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
>
> ---
> v2: Fix a couple of spelling errors.
> ---
>  drivers/net/dsa/mv88e6xxx/global1.c | 5 +++++
>  drivers/net/dsa/mv88e6xxx/global1.h | 1 +
>  2 files changed, 6 insertions(+)
>
> diff --git a/drivers/net/dsa/mv88e6xxx/global1.c b/drivers/net/dsa/mv88e6xxx/global1.c
> index 120a65d3e3ef..b016cc205f81 100644
> --- a/drivers/net/dsa/mv88e6xxx/global1.c
> +++ b/drivers/net/dsa/mv88e6xxx/global1.c
> @@ -360,6 +360,11 @@ int mv88e6390_g1_set_cpu_port(struct mv88e6xxx_chip *chip, int port)
>  {
>         u16 ptr = MV88E6390_G1_MONITOR_MGMT_CTL_PTR_CPU_DEST;
>
> +       /* Use the default high priority for management frames sent to
> +        * the CPU.
> +        */
> +       port |= MV88E6390_G1_MONITOR_MGMT_CTL_PTR_CPU_DEST_MGMTPRI;
> +
>         return mv88e6390_g1_monitor_write(chip, ptr, port);
>  }
>
> diff --git a/drivers/net/dsa/mv88e6xxx/global1.h b/drivers/net/dsa/mv88e6xxx/global1.h
> index bc5a6b2bb1e4..5324c6f4ae90 100644
> --- a/drivers/net/dsa/mv88e6xxx/global1.h
> +++ b/drivers/net/dsa/mv88e6xxx/global1.h
> @@ -211,6 +211,7 @@
>  #define MV88E6390_G1_MONITOR_MGMT_CTL_PTR_INGRESS_DEST         0x2000
>  #define MV88E6390_G1_MONITOR_MGMT_CTL_PTR_EGRESS_DEST          0x2100
>  #define MV88E6390_G1_MONITOR_MGMT_CTL_PTR_CPU_DEST             0x3000
> +#define MV88E6390_G1_MONITOR_MGMT_CTL_PTR_CPU_DEST_MGMTPRI     0x00e0
>  #define MV88E6390_G1_MONITOR_MGMT_CTL_DATA_MASK                        0x00ff
>
>  /* Offset 0x1C: Global Control 2 */
> --
> 2.24.0
>

From: Andrew Lunn <andrew@lunn.ch>
Date: Sat,  4 Jan 2020 23:14:51 +0100

> The 6390 family uses an extended register to set the port connected to
> the CPU. The lower 5 bits indicate the port, the upper three bits are
> the priority of the frames as they pass through the switch, what
> egress queue they should use, etc. Since frames being set to the CPU
> are typically management frames, BPDU, IGMP, ARP, etc set the priority
> to 7, the reset default, and the highest.
> 
> Fixes: 33641994a676 ("net: dsa: mv88e6xxx: Monitor and Management tables")
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> 
> ---
> v2: Fix a couple of spelling errors.

Applied and queued up for -stable, thanks Andrew.