net: dsa: Mock-up driver

This patch adds support for a DSA mock-up driver which essentially does
the following:

- registers/unregisters 4 fixed PHYs to the slave network devices
- uses eth0 (configurable) as the master netdev
- registers the switch as a fixed MDIO device against the fixed MDIO bus
  at address 31
- includes dynamic debug prints for dsa_switch_ops functions that can be
  enabled to get call traces

This is a good way to test modular builds as well as exercise the DSA
APIs without requiring access to real hardware. This does not test the
data-path, although this could be added later on.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 390 insertions, 1 deletions

diff --git a/drivers/net/dsa/Kconfig b/drivers/net/dsa/Kconfig
index 564b267c8428..ba2e655eec19 100644
--- a/drivers/net/dsa/Kconfig
+++ b/drivers/net/dsa/Kconfig
@@ -34,4 +34,12 @@ config NET_DSA_QCA8K
           This enables support for the Qualcomm Atheros QCA8K Ethernet
           switch chips.
 
+config NET_DSA_LOOP
+        tristate "DSA mock-up Ethernet switch chip support"
+        depends on NET_DSA
+        select FIXED_PHY
+        ---help---
+          This enables support for a fake mock-up switch chip which
+          exercises the DSA APIs.
+
 endmenu
diff --git a/drivers/net/dsa/Makefile b/drivers/net/dsa/Makefile
index a3c941632217..5c8830991041 100644
--- a/drivers/net/dsa/Makefile
+++ b/drivers/net/dsa/Makefile
@@ -2,6 +2,6 @@ obj-$(CONFIG_NET_DSA_MV88E6060) += mv88e6060.o
 obj-$(CONFIG_NET_DSA_BCM_SF2)   += bcm-sf2.o
 bcm-sf2-objs                    := bcm_sf2.o bcm_sf2_cfp.o
 obj-$(CONFIG_NET_DSA_QCA8K)     += qca8k.o
-
 obj-y                           += b53/
 obj-y                           += mv88e6xxx/
+obj-$(CONFIG_NET_DSA_LOOP)      += dsa_loop.o dsa_loop_bdinfo.o
diff --git a/drivers/net/dsa/dsa_loop.c b/drivers/net/dsa/dsa_loop.c
new file mode 100644
index 000000000000..bc5acc15edbf
--- /dev/null
+++ b/drivers/net/dsa/dsa_loop.c
@@ -0,0 +1,328 @@
+/*
+ * Distributed Switch Architecture loopback driver
+ *
+ * Copyright (C) 2016, Florian Fainelli <f.fainelli@gmail.com>
+ *
+ * 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/platform_device.h>
+#include <linux/netdevice.h>
+#include <linux/phy.h>
+#include <linux/phy_fixed.h>
+#include <linux/export.h>
+#include <linux/workqueue.h>
+#include <linux/module.h>
+#include <linux/if_bridge.h>
+#include <net/switchdev.h>
+#include <net/dsa.h>
+
+#include "dsa_loop.h"
+
+struct dsa_loop_vlan {
+        u16 members;
+        u16 untagged;
+};
+
+#define DSA_LOOP_VLANS  5
+
+struct dsa_loop_priv {
+        struct mii_bus  *bus;
+        unsigned int    port_base;
+        struct dsa_loop_vlan vlans[DSA_LOOP_VLANS];
+        struct net_device *netdev;
+        u16 pvid;
+};
+
+static struct phy_device *phydevs[PHY_MAX_ADDR];
+
+static enum dsa_tag_protocol dsa_loop_get_protocol(struct dsa_switch *ds)
+{
+        dev_dbg(ds->dev, "%s\n", __func__);
+
+        return DSA_TAG_PROTO_NONE;
+}
+
+static int dsa_loop_setup(struct dsa_switch *ds)
+{
+        dev_dbg(ds->dev, "%s\n", __func__);
+
+        return 0;
+}
+
+static int dsa_loop_set_addr(struct dsa_switch *ds, u8 *addr)
+{
+        dev_dbg(ds->dev, "%s\n", __func__);
+
+        return 0;
+}
+
+static int dsa_loop_phy_read(struct dsa_switch *ds, int port, int regnum)
+{
+        struct dsa_loop_priv *ps = ds->priv;
+        struct mii_bus *bus = ps->bus;
+
+        dev_dbg(ds->dev, "%s\n", __func__);
+
+        return mdiobus_read_nested(bus, ps->port_base + port, regnum);
+}
+
+static int dsa_loop_phy_write(struct dsa_switch *ds, int port,
+                              int regnum, u16 value)
+{
+        struct dsa_loop_priv *ps = ds->priv;
+        struct mii_bus *bus = ps->bus;
+
+        dev_dbg(ds->dev, "%s\n", __func__);
+
+        return mdiobus_write_nested(bus, ps->port_base + port, regnum, value);
+}
+
+static int dsa_loop_port_bridge_join(struct dsa_switch *ds, int port,
+                                     struct net_device *bridge)
+{
+        dev_dbg(ds->dev, "%s\n", __func__);
+
+        return 0;
+}
+
+static void dsa_loop_port_bridge_leave(struct dsa_switch *ds, int port,
+                                       struct net_device *bridge)
+{
+        dev_dbg(ds->dev, "%s\n", __func__);
+}
+
+static void dsa_loop_port_stp_state_set(struct dsa_switch *ds, int port,
+                                        u8 state)
+{
+        dev_dbg(ds->dev, "%s\n", __func__);
+}
+
+static int dsa_loop_port_vlan_filtering(struct dsa_switch *ds, int port,
+                                        bool vlan_filtering)
+{
+        dev_dbg(ds->dev, "%s\n", __func__);
+
+        return 0;
+}
+
+static int dsa_loop_port_vlan_prepare(struct dsa_switch *ds, int port,
+                                      const struct switchdev_obj_port_vlan *vlan,
+                                      struct switchdev_trans *trans)
+{
+        struct dsa_loop_priv *ps = ds->priv;
+        struct mii_bus *bus = ps->bus;
+
+        dev_dbg(ds->dev, "%s\n", __func__);
+
+        /* Just do a sleeping operation to make lockdep checks effective */
+        mdiobus_read(bus, ps->port_base + port, MII_BMSR);
+
+        if (vlan->vid_end > DSA_LOOP_VLANS)
+                return -ERANGE;
+
+        return 0;
+}
+
+static void dsa_loop_port_vlan_add(struct dsa_switch *ds, int port,
+                                   const struct switchdev_obj_port_vlan *vlan,
+                                   struct switchdev_trans *trans)
+{
+        bool untagged = vlan->flags & BRIDGE_VLAN_INFO_UNTAGGED;
+        bool pvid = vlan->flags & BRIDGE_VLAN_INFO_PVID;
+        struct dsa_loop_priv *ps = ds->priv;
+        struct mii_bus *bus = ps->bus;
+        struct dsa_loop_vlan *vl;
+        u16 vid;
+
+        dev_dbg(ds->dev, "%s\n", __func__);
+
+        /* Just do a sleeping operation to make lockdep checks effective */
+        mdiobus_read(bus, ps->port_base + port, MII_BMSR);
+
+        for (vid = vlan->vid_begin; vid <= vlan->vid_end; ++vid) {
+                vl = &ps->vlans[vid];
+
+                vl->members |= BIT(port);
+                if (untagged)
+                        vl->untagged |= BIT(port);
+                else
+                        vl->untagged &= ~BIT(port);
+        }
+
+        if (pvid)
+                ps->pvid = vid;
+}
+
+static int dsa_loop_port_vlan_del(struct dsa_switch *ds, int port,
+                                  const struct switchdev_obj_port_vlan *vlan)
+{
+        bool untagged = vlan->flags & BRIDGE_VLAN_INFO_UNTAGGED;
+        struct dsa_loop_priv *ps = ds->priv;
+        struct mii_bus *bus = ps->bus;
+        struct dsa_loop_vlan *vl;
+        u16 vid, pvid;
+
+        dev_dbg(ds->dev, "%s\n", __func__);
+
+        /* Just do a sleeping operation to make lockdep checks effective */
+        mdiobus_read(bus, ps->port_base + port, MII_BMSR);
+
+        for (vid = vlan->vid_begin; vid <= vlan->vid_end; ++vid) {
+                vl = &ps->vlans[vid];
+
+                vl->members &= ~BIT(port);
+                if (untagged)
+                        vl->untagged &= ~BIT(port);
+
+                if (pvid == vid)
+                        pvid = 1;
+        }
+        ps->pvid = pvid;
+
+        return 0;
+}
+
+static int dsa_loop_port_vlan_dump(struct dsa_switch *ds, int port,
+                                   struct switchdev_obj_port_vlan *vlan,
+                                   int (*cb)(struct switchdev_obj *obj))
+{
+        struct dsa_loop_priv *ps = ds->priv;
+        struct mii_bus *bus = ps->bus;
+        struct dsa_loop_vlan *vl;
+        u16 vid, vid_start = 0;
+        int err;
+
+        dev_dbg(ds->dev, "%s\n", __func__);
+
+        /* Just do a sleeping operation to make lockdep checks effective */
+        mdiobus_read(bus, ps->port_base + port, MII_BMSR);
+
+        for (vid = vid_start; vid < DSA_LOOP_VLANS; vid++) {
+                vl = &ps->vlans[vid];
+
+                if (!(vl->members & BIT(port)))
+                        continue;
+
+                vlan->vid_begin = vlan->vid_end = vid;
+                vlan->flags = 0;
+
+                if (vl->untagged & BIT(port))
+                        vlan->flags |= BRIDGE_VLAN_INFO_UNTAGGED;
+                if (ps->pvid == vid)
+                        vlan->flags |= BRIDGE_VLAN_INFO_PVID;
+
+                err = cb(&vlan->obj);
+                if (err)
+                        break;
+        }
+
+        return err;
+}
+
+static struct dsa_switch_ops dsa_loop_driver = {
+        .get_tag_protocol       = dsa_loop_get_protocol,
+        .setup                  = dsa_loop_setup,
+        .set_addr               = dsa_loop_set_addr,
+        .phy_read               = dsa_loop_phy_read,
+        .phy_write              = dsa_loop_phy_write,
+        .port_bridge_join       = dsa_loop_port_bridge_join,
+        .port_bridge_leave      = dsa_loop_port_bridge_leave,
+        .port_stp_state_set     = dsa_loop_port_stp_state_set,
+        .port_vlan_filtering    = dsa_loop_port_vlan_filtering,
+        .port_vlan_prepare      = dsa_loop_port_vlan_prepare,
+        .port_vlan_add          = dsa_loop_port_vlan_add,
+        .port_vlan_del          = dsa_loop_port_vlan_del,
+        .port_vlan_dump         = dsa_loop_port_vlan_dump,
+};
+
+static int dsa_loop_drv_probe(struct mdio_device *mdiodev)
+{
+        struct dsa_loop_pdata *pdata = mdiodev->dev.platform_data;
+        struct dsa_loop_priv *ps;
+        struct dsa_switch *ds;
+
+        if (!pdata)
+                return -ENODEV;
+
+        dev_info(&mdiodev->dev, "%s: 0x%0x\n",
+                 pdata->name, pdata->enabled_ports);
+
+        ds = dsa_switch_alloc(&mdiodev->dev, DSA_MAX_PORTS);
+        if (!ds)
+                return -ENOMEM;
+
+        ps = devm_kzalloc(&mdiodev->dev, sizeof(*ps), GFP_KERNEL);
+        ps->netdev = dev_get_by_name(&init_net, pdata->netdev);
+        if (!ps->netdev)
+                return -EPROBE_DEFER;
+
+        pdata->cd.netdev[DSA_LOOP_CPU_PORT] = &ps->netdev->dev;
+
+        ds->dev = &mdiodev->dev;
+        ds->ops = &dsa_loop_driver;
+        ds->priv = ps;
+        ps->bus = mdiodev->bus;
+
+        dev_set_drvdata(&mdiodev->dev, ds);
+
+        return dsa_register_switch(ds, ds->dev);
+}
+
+static void dsa_loop_drv_remove(struct mdio_device *mdiodev)
+{
+        struct dsa_switch *ds = dev_get_drvdata(&mdiodev->dev);
+        struct dsa_loop_priv *ps = ds->priv;
+
+        dsa_unregister_switch(ds);
+        dev_put(ps->netdev);
+}
+
+static struct mdio_driver dsa_loop_drv = {
+        .mdiodrv.driver = {
+                .name   = "dsa-loop",
+        },
+        .probe  = dsa_loop_drv_probe,
+        .remove = dsa_loop_drv_remove,
+};
+
+#define NUM_FIXED_PHYS  (DSA_LOOP_NUM_PORTS - 2)
+
+static void unregister_fixed_phys(void)
+{
+        unsigned int i;
+
+        for (i = 0; i < NUM_FIXED_PHYS; i++)
+                if (phydevs[i])
+                        fixed_phy_unregister(phydevs[i]);
+}
+
+static int __init dsa_loop_init(void)
+{
+        struct fixed_phy_status status = {
+                .link = 1,
+                .speed = SPEED_100,
+                .duplex = DUPLEX_FULL,
+        };
+        unsigned int i;
+
+        for (i = 0; i < NUM_FIXED_PHYS; i++)
+                phydevs[i] = fixed_phy_register(PHY_POLL, &status, -1, NULL);
+
+        return mdio_driver_register(&dsa_loop_drv);
+}
+module_init(dsa_loop_init);
+
+static void __exit dsa_loop_exit(void)
+{
+        mdio_driver_unregister(&dsa_loop_drv);
+        unregister_fixed_phys();
+}
+module_exit(dsa_loop_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Florian Fainelli");
+MODULE_DESCRIPTION("DSA loopback driver");
diff --git a/drivers/net/dsa/dsa_loop.h b/drivers/net/dsa/dsa_loop.h
new file mode 100644
index 000000000000..dc396877fc95
--- /dev/null
+++ b/drivers/net/dsa/dsa_loop.h
@@ -0,0 +1,19 @@
+#ifndef __DSA_LOOP_H
+#define __DSA_LOOP_H
+
+struct dsa_chip_data;
+
+struct dsa_loop_pdata {
+        /* Must be first, such that dsa_register_switch() can access this
+         * without gory pointer manipulations
+         */
+        struct dsa_chip_data cd;
+        const char *name;
+        unsigned int enabled_ports;
+        const char *netdev;
+};
+
+#define DSA_LOOP_NUM_PORTS      6
+#define DSA_LOOP_CPU_PORT       (DSA_LOOP_NUM_PORTS - 1)
+
+#endif /* __DSA_LOOP_H */
diff --git a/drivers/net/dsa/dsa_loop_bdinfo.c b/drivers/net/dsa/dsa_loop_bdinfo.c
new file mode 100644
index 000000000000..fb8d5dc71013
--- /dev/null
+++ b/drivers/net/dsa/dsa_loop_bdinfo.c
@@ -0,0 +1,34 @@
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/phy.h>
+#include <net/dsa.h>
+
+#include "dsa_loop.h"
+
+static struct dsa_loop_pdata dsa_loop_pdata = {
+        .cd = {
+                .port_names[0] = "lan1",
+                .port_names[1] = "lan2",
+                .port_names[2] = "lan3",
+                .port_names[3] = "lan4",
+                .port_names[DSA_LOOP_CPU_PORT] = "cpu",
+        },
+        .name = "DSA mockup driver",
+        .enabled_ports = 0x1f,
+        .netdev = "eth0",
+};
+
+static const struct mdio_board_info bdinfo = {
+        .bus_id = "fixed-0",
+        .modalias = "dsa-loop",
+        .mdio_addr = 31,
+        .platform_data = &dsa_loop_pdata,
+};
+
+static int __init dsa_loop_bdinfo_init(void)
+{
+        return mdiobus_register_board_info(&bdinfo, 1);
+}
+arch_initcall(dsa_loop_bdinfo_init)
+
+MODULE_LICENSE("GPL");