net: dsa: felix: create a template for the DSA tags on xmit

With this patch we try to kill 2 birds with 1 stone.

First of all, some switches that use tag_ocelot.c don't have the exact
same bitfield layout for the DSA tags. The destination ports field is
different for Seville VSC9953 for example. So the choices are to either
duplicate tag_ocelot.c into a new tag_seville.c (sub-optimal) or somehow
take into account a supposed ocelot->dest_ports_offset when packing this
field into the DSA injection header (again not ideal).

Secondly, tag_ocelot.c already needs to memset a 128-bit area to zero
and call some packing() functions of dubious performance in the
fastpath. And most of the values it needs to pack are pretty much
constant (BYPASS=1, SRC_PORT=CPU, DEST=port index). So it would be good
if we could improve that.

The proposed solution is to allocate a memory area per port at probe
time, initialize that with the statically defined bits as per chip
hardware revision, and just perform a simpler memcpy in the fastpath.

Other alternatives have been analyzed, such as:
- Create a separate tag_seville.c: too much code duplication for just 1
  bit field difference.
- Create a separate DSA_TAG_PROTO_SEVILLE under tag_ocelot.c, just like
  tag_brcm.c, which would have a separate .xmit function. Again, too
  much code duplication for just 1 bit field difference.
- Allocate the template from the init function of the tag_ocelot.c
  module, instead of from the driver: couldn't figure out a method of
  accessing the correct port template corresponding to the correct
  tagger in the .xmit function.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
index 4b255ed614e47491ef2f5f8e1684867bd6dd3835..b9981d8c4c98b93902addb47b41a9e19d092d0b6 100644 (file)
--- a/drivers/net/dsa/ocelot/felix.c
+++ b/drivers/net/dsa/ocelot/felix.c
@@ -522,6 +522,7 @@ static int felix_init_structs(struct felix *felix, int num_phys_ports)
        for (port = 0; port < num_phys_ports; port++) {
                struct ocelot_port *ocelot_port;
                struct regmap *target;
+               u8 *template;
 
                ocelot_port = devm_kzalloc(ocelot->dev,
                                           sizeof(struct ocelot_port),
@@ -547,10 +548,22 @@ static int felix_init_structs(struct felix *felix, int num_phys_ports)
                        return PTR_ERR(target);
                }
 
+               template = devm_kzalloc(ocelot->dev, OCELOT_TAG_LEN,
+                                       GFP_KERNEL);
+               if (!template) {
+                       dev_err(ocelot->dev,
+                               "Failed to allocate memory for DSA tag\n");
+                       kfree(port_phy_modes);
+                       return -ENOMEM;
+               }
+
                ocelot_port->phy_mode = port_phy_modes[port];
                ocelot_port->ocelot = ocelot;
                ocelot_port->target = target;
+               ocelot_port->xmit_template = template;
                ocelot->ports[port] = ocelot_port;
+
+               felix->info->xmit_template_populate(ocelot, port);
        }
 
        kfree(port_phy_modes);

diff --git a/drivers/net/dsa/ocelot/felix.h b/drivers/net/dsa/ocelot/felix.h
index 00137b64132b2e3024eb8b7c3208d533eea4c0e9..a85631d716b94c2a58bb526e1d5b885fc91438c2 100644 (file)
--- a/drivers/net/dsa/ocelot/felix.h
+++ b/drivers/net/dsa/ocelot/felix.h
@@ -43,6 +43,7 @@ struct felix_info {
                                 enum tc_setup_type type, void *type_data);
        void    (*port_sched_speed_set)(struct ocelot *ocelot, int port,
                                        u32 speed);
+       void    (*xmit_template_populate)(struct ocelot *ocelot, int port);
 };
 
 extern struct felix_info               felix_info_vsc9959;

diff --git a/drivers/net/dsa/ocelot/felix_vsc9959.c b/drivers/net/dsa/ocelot/felix_vsc9959.c
index efbfbdccb2b6972af8bc2d1a6491701ed82017a2..d640146acc3dda7550efd6cb0c9a3a15b8d43b8e 100644 (file)
--- a/drivers/net/dsa/ocelot/felix_vsc9959.c
+++ b/drivers/net/dsa/ocelot/felix_vsc9959.c
@@ -8,6 +8,7 @@
 #include <soc/mscc/ocelot_ptp.h>
 #include <soc/mscc/ocelot_sys.h>
 #include <soc/mscc/ocelot.h>
+#include <linux/packing.h>
 #include <net/pkt_sched.h>
 #include <linux/iopoll.h>
 #include <linux/pci.h>
@@ -1432,6 +1433,24 @@ static int vsc9959_port_setup_tc(struct dsa_switch *ds, int port,
        }
 }
 
+static void vsc9959_xmit_template_populate(struct ocelot *ocelot, int port)
+{
+       struct ocelot_port *ocelot_port = ocelot->ports[port];
+       u8 *template = ocelot_port->xmit_template;
+       u64 bypass, dest, src;
+
+       /* Set the source port as the CPU port module and not the
+        * NPI port
+        */
+       src = ocelot->num_phys_ports;
+       dest = BIT(port);
+       bypass = true;
+
+       packing(template, &bypass, 127, 127, OCELOT_TAG_LEN, PACK, 0);
+       packing(template, &dest,    68,  56, OCELOT_TAG_LEN, PACK, 0);
+       packing(template, &src,     46,  43, OCELOT_TAG_LEN, PACK, 0);
+}
+
 struct felix_info felix_info_vsc9959 = {
        .target_io_res          = vsc9959_target_io_res,
        .port_io_res            = vsc9959_port_io_res,
@@ -1458,4 +1477,5 @@ struct felix_info felix_info_vsc9959 = {
        .prevalidate_phy_mode   = vsc9959_prevalidate_phy_mode,
        .port_setup_tc          = vsc9959_port_setup_tc,
        .port_sched_speed_set   = vsc9959_sched_speed_set,
+       .xmit_template_populate = vsc9959_xmit_template_populate,
 };

diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index 19d97585345a459563522e9391ff1c7422e9e8c6..6cfbace5777027e9487290b30905a0d715f95d41 100644 (file)
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -564,6 +564,8 @@ struct ocelot_port {
        u8                              ts_id;
 
        phy_interface_t                 phy_mode;
+
+       u8                              *xmit_template;
 };
 
 struct ocelot {

diff --git a/net/dsa/tag_ocelot.c b/net/dsa/tag_ocelot.c
index b0c98ee4e13b39e2d7e5af5a559bbdf44726cec4..42f327c06dcacea54458d8a3d6e8cd154da2687a 100644 (file)
--- a/net/dsa/tag_ocelot.c
+++ b/net/dsa/tag_ocelot.c
@@ -137,11 +137,10 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
                                   struct net_device *netdev)
 {
        struct dsa_port *dp = dsa_slave_to_port(netdev);
-       u64 bypass, dest, src, qos_class, rew_op;
        struct dsa_switch *ds = dp->ds;
-       int port = dp->index;
        struct ocelot *ocelot = ds->priv;
-       struct ocelot_port *ocelot_port = ocelot->ports[port];
+       struct ocelot_port *ocelot_port;
+       u64 qos_class, rew_op;
        u8 *injection;
 
        if (unlikely(skb_cow_head(skb, OCELOT_TAG_LEN) < 0)) {
@@ -149,19 +148,15 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
                return NULL;
        }
 
-       injection = skb_push(skb, OCELOT_TAG_LEN);
+       ocelot_port = ocelot->ports[dp->index];
 
-       memset(injection, 0, OCELOT_TAG_LEN);
+       injection = skb_push(skb, OCELOT_TAG_LEN);
 
-       /* Set the source port as the CPU port module and not the NPI port */
-       src = ocelot->num_phys_ports;
-       dest = BIT(port);
-       bypass = true;
+       memcpy(injection, ocelot_port->xmit_template, OCELOT_TAG_LEN);
+       /* Fix up the fields which are not statically determined
+        * in the template
+        */
        qos_class = skb->priority;
-
-       packing(injection, &bypass,   127, 127, OCELOT_TAG_LEN, PACK, 0);
-       packing(injection, &dest,      68,  56, OCELOT_TAG_LEN, PACK, 0);
-       packing(injection, &src,       46,  43, OCELOT_TAG_LEN, PACK, 0);
        packing(injection, &qos_class, 19,  17, OCELOT_TAG_LEN, PACK, 0);
 
        if (ocelot->ptp && (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {