Re: [PATCH net-next 1/3] net: lan966x: Add function lan966x_mac_cpu_copy()

[Vladimir Oltean]

On Mon, Jan 03, 2022 at 02:10:37PM +0100, Horatiu Vultur wrote:
> Extend mac functionality with the function lan966x_mac_cpu_copy. This
> function adds an entry in the MAC table where a frame is copy to the CPU

s/copy/copied/

> but also can be forward on the front ports.

s/forward/forwarded/

> This functionality is needed for mdb support. In case the CPU and some
> of the front ports subscribe to an IP multicast address.
> 
> Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
> ---
>  .../ethernet/microchip/lan966x/lan966x_mac.c  | 27 ++++++++++++++++---
>  .../ethernet/microchip/lan966x/lan966x_main.h |  5 ++++
>  .../ethernet/microchip/lan966x/lan966x_regs.h |  6 +++++
>  3 files changed, 34 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
> index efadb8d326cc..ae3a7a10e0d6 100644
> --- a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
> +++ b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
> @@ -68,16 +68,18 @@ static void lan966x_mac_select(struct lan966x *lan966x,
>  	lan_wr(mach, lan966x, ANA_MACHDATA);
>  }
>  
> -int lan966x_mac_learn(struct lan966x *lan966x, int port,
> -		      const unsigned char mac[ETH_ALEN],
> -		      unsigned int vid,
> -		      enum macaccess_entry_type type)
> +static int lan966x_mac_learn_impl(struct lan966x *lan966x, int port,
> +				  bool cpu_copy,
> +				  const unsigned char mac[ETH_ALEN],
> +				  unsigned int vid,
> +				  enum macaccess_entry_type type)

In the kernel, the __lan966x_mac_learn naming scheme seems to be more
popular than _impl.

Also, may I suggest that the "int port" argument may be better named
"int pgid"?

>  {
>  	lan966x_mac_select(lan966x, mac, vid);
>  
>  	/* Issue a write command */
>  	lan_wr(ANA_MACACCESS_VALID_SET(1) |
>  	       ANA_MACACCESS_CHANGE2SW_SET(0) |
> +	       ANA_MACACCESS_MAC_CPU_COPY_SET(cpu_copy) |
>  	       ANA_MACACCESS_DEST_IDX_SET(port) |
>  	       ANA_MACACCESS_ENTRYTYPE_SET(type) |
>  	       ANA_MACACCESS_MAC_TABLE_CMD_SET(MACACCESS_CMD_LEARN),
> @@ -86,6 +88,23 @@ int lan966x_mac_learn(struct lan966x *lan966x, int port,
>  	return lan966x_mac_wait_for_completion(lan966x);
>  }
>  
> +int lan966x_mac_cpu_copy(struct lan966x *lan966x, int port,
> +			 bool cpu_copy,
> +			 const unsigned char mac[ETH_ALEN],
> +			 unsigned int vid,
> +			 enum macaccess_entry_type type)

This doesn't seem to use the "port" argument from any of its call sites.
It is always 0. What would it even mean?

> +{
> +	return lan966x_mac_learn_impl(lan966x, port, cpu_copy, mac, vid, type);
> +}
> +
> +int lan966x_mac_learn(struct lan966x *lan966x, int port,
> +		      const unsigned char mac[ETH_ALEN],
> +		      unsigned int vid,
> +		      enum macaccess_entry_type type)
> +{
> +	return lan966x_mac_learn_impl(lan966x, port, false, mac, vid, type);

If you call lan966x_mac_cpu_copy() on an address and then
lan966x_mac_learn() on the same address but on an external port, how
does that work (why doesn't the "false" here overwrite the cpu_copy in
the previous command, breaking the copy-to-CPU feature)?

> +}
> +
>  int lan966x_mac_forget(struct lan966x *lan966x,
>  		       const unsigned char mac[ETH_ALEN],
>  		       unsigned int vid,
> diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
> index c399b1256edc..a7a2a3537036 100644
> --- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
> +++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
> @@ -157,6 +157,11 @@ int lan966x_port_pcs_set(struct lan966x_port *port,
>  			 struct lan966x_port_config *config);
>  void lan966x_port_init(struct lan966x_port *port);
>  
> +int lan966x_mac_cpu_copy(struct lan966x *lan966x, int port,
> +			 bool cpu_copy,
> +			 const unsigned char mac[ETH_ALEN],
> +			 unsigned int vid,
> +			 enum macaccess_entry_type type);
>  int lan966x_mac_learn(struct lan966x *lan966x, int port,
>  		      const unsigned char mac[ETH_ALEN],
>  		      unsigned int vid,
> diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_regs.h b/drivers/net/ethernet/microchip/lan966x/lan966x_regs.h
> index a13c469e139a..797560172aca 100644
> --- a/drivers/net/ethernet/microchip/lan966x/lan966x_regs.h
> +++ b/drivers/net/ethernet/microchip/lan966x/lan966x_regs.h
> @@ -169,6 +169,12 @@ enum lan966x_target {
>  #define ANA_MACACCESS_CHANGE2SW_GET(x)\
>  	FIELD_GET(ANA_MACACCESS_CHANGE2SW, x)
>  
> +#define ANA_MACACCESS_MAC_CPU_COPY               BIT(16)
> +#define ANA_MACACCESS_MAC_CPU_COPY_SET(x)\
> +	FIELD_PREP(ANA_MACACCESS_MAC_CPU_COPY, x)
> +#define ANA_MACACCESS_MAC_CPU_COPY_GET(x)\
> +	FIELD_GET(ANA_MACACCESS_MAC_CPU_COPY, x)
> +
>  #define ANA_MACACCESS_VALID                      BIT(12)
>  #define ANA_MACACCESS_VALID_SET(x)\
>  	FIELD_PREP(ANA_MACACCESS_VALID, x)
> -- 
> 2.33.0
>