Re: [PATCH v3 net-next 1/5] dsa: add support for Microchip KSZ tail tagging

[Florian Fainelli <f.fainelli@gmail.com>]

On 05/19/2017 03:57 PM, Woojung.Huh@microchip.com wrote:
> From: Woojung Huh <Woojung.Huh@microchip.com>
> 
> Adding support for the Microchip KSZ switch family tail tagging.
> 
> Signed-off-by: Woojung Huh <Woojung.Huh@microchip.com>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> ---
>  include/net/dsa.h  |   1 +
>  net/dsa/Kconfig    |   3 ++
>  net/dsa/Makefile   |   1 +
>  net/dsa/dsa.c      |   3 ++
>  net/dsa/dsa_priv.h |   3 ++
>  net/dsa/tag_ksz.c  | 103 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  6 files changed, 114 insertions(+)
>  create mode 100644 net/dsa/tag_ksz.c
> 
> diff --git a/include/net/dsa.h b/include/net/dsa.h
> index 791fed6..fbb00a6 100644
> --- a/include/net/dsa.h
> +++ b/include/net/dsa.h
> @@ -31,6 +31,7 @@ enum dsa_tag_protocol {
>  	DSA_TAG_PROTO_BRCM,
>  	DSA_TAG_PROTO_DSA,
>  	DSA_TAG_PROTO_EDSA,
> +	DSA_TAG_PROTO_KSZ,
>  	DSA_TAG_PROTO_LAN9303,
>  	DSA_TAG_PROTO_MTK,
>  	DSA_TAG_PROTO_QCA,
> diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
> index 297389b..cc5f8f9 100644
> --- a/net/dsa/Kconfig
> +++ b/net/dsa/Kconfig
> @@ -25,6 +25,9 @@ config NET_DSA_TAG_DSA
>  config NET_DSA_TAG_EDSA
>  	bool
>  
> +config NET_DSA_TAG_KSZ
> +	bool
> +
>  config NET_DSA_TAG_LAN9303
>  	bool
>  
> diff --git a/net/dsa/Makefile b/net/dsa/Makefile
> index f8c0251..b15141f 100644
> --- a/net/dsa/Makefile
> +++ b/net/dsa/Makefile
> @@ -6,6 +6,7 @@ dsa_core-y += dsa.o slave.o dsa2.o switch.o legacy.o
>  dsa_core-$(CONFIG_NET_DSA_TAG_BRCM) += tag_brcm.o
>  dsa_core-$(CONFIG_NET_DSA_TAG_DSA) += tag_dsa.o
>  dsa_core-$(CONFIG_NET_DSA_TAG_EDSA) += tag_edsa.o
> +dsa_core-$(CONFIG_NET_DSA_TAG_KSZ) += tag_ksz.o
>  dsa_core-$(CONFIG_NET_DSA_TAG_LAN9303) += tag_lan9303.o
>  dsa_core-$(CONFIG_NET_DSA_TAG_MTK) += tag_mtk.o
>  dsa_core-$(CONFIG_NET_DSA_TAG_QCA) += tag_qca.o
> diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
> index 3288a80..402459e 100644
> --- a/net/dsa/dsa.c
> +++ b/net/dsa/dsa.c
> @@ -49,6 +49,9 @@ const struct dsa_device_ops *dsa_device_ops[DSA_TAG_LAST] = {
>  #ifdef CONFIG_NET_DSA_TAG_EDSA
>  	[DSA_TAG_PROTO_EDSA] = &edsa_netdev_ops,
>  #endif
> +#ifdef CONFIG_NET_DSA_TAG_KSZ
> +	[DSA_TAG_PROTO_KSZ] = &ksz_netdev_ops,
> +#endif
>  #ifdef CONFIG_NET_DSA_TAG_LAN9303
>  	[DSA_TAG_PROTO_LAN9303] = &lan9303_netdev_ops,
>  #endif
> diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
> index c274130..6f23dfa 100644
> --- a/net/dsa/dsa_priv.h
> +++ b/net/dsa/dsa_priv.h
> @@ -85,6 +85,9 @@ extern const struct dsa_device_ops dsa_netdev_ops;
>  /* tag_edsa.c */
>  extern const struct dsa_device_ops edsa_netdev_ops;
>  
> +/* tag_ksz.c */
> +extern const struct dsa_device_ops ksz_netdev_ops;
> +
>  /* tag_lan9303.c */
>  extern const struct dsa_device_ops lan9303_netdev_ops;
>  
> diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c
> new file mode 100644
> index 0000000..cbc79b5
> --- /dev/null
> +++ b/net/dsa/tag_ksz.c
> @@ -0,0 +1,103 @@
> +/*
> + * net/dsa/tag_ksz.c - Microchip KSZ Switch tag format handling
> + * Copyright (c) 2017 Microchip Technology
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#include <linux/etherdevice.h>
> +#include <linux/list.h>
> +#include <linux/slab.h>
> +#include <net/dsa.h>
> +#include "dsa_priv.h"
> +
> +/* For Ingress (Host -> KSZ), 2 bytes are added before FCS.
> + * ---------------------------------------------------------------------------
> + * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes)
> + * ---------------------------------------------------------------------------
> + * tag0 : Prioritization (not used now)
> + * tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
> + *
> + * For Egress (KSZ -> Host), 1 byte is added before FCS.
> + * ---------------------------------------------------------------------------
> + * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
> + * ---------------------------------------------------------------------------
> + * tag0 : zero-based value represents port
> + *	  (eg, 0x00=port1, 0x02=port3, 0x06=port7)
> + */
> +
> +#define	KSZ_INGRESS_TAG_LEN	2
> +#define	KSZ_EGRESS_TAG_LEN	1
> +
> +static struct sk_buff *ksz_xmit(struct sk_buff *skb, struct net_device *dev)
> +{
> +	struct dsa_slave_priv *p = netdev_priv(dev);
> +	struct sk_buff *nskb;
> +	int padlen;
> +	u8 *tag;
> +
> +	padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len;
> +
> +	if (skb_tailroom(skb) >= padlen + KSZ_INGRESS_TAG_LEN) {
> +		nskb = skb;
> +	} else {
> +		nskb = alloc_skb(NET_IP_ALIGN + skb->len +
> +				 padlen + KSZ_INGRESS_TAG_LEN, GFP_ATOMIC);
> +		if (!nskb) {
> +			kfree_skb(skb);
> +			return NULL;
> +		}
> +		skb_reserve(nskb, NET_IP_ALIGN);
> +
> +		skb_reset_mac_header(nskb);
> +		skb_set_network_header(nskb,
> +				       skb_network_header(skb) - skb->head);
> +		skb_set_transport_header(nskb,
> +					 skb_transport_header(skb) - skb->head);
> +		skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len));
> +		kfree_skb(skb);
> +	}
> +
> +	if (padlen) {
> +		u8 *pad = skb_put(nskb, padlen);
> +
> +		memset(pad, 0, padlen);
> +	}

Can you use skb_put_padto() here instead of open coding this?

> +
> +	tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN);
> +	tag[0] = 0;
> +	tag[1] = 1 << p->dp->index; /* destnation port */

typo: destination port

With that fixed:

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian