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linux/drivers/net/dsa/b53/b53_priv.h
Vladimir Oltean 0650bf52b3 net: dsa: be compatible with masters which unregister on shutdown 
Lino reports that on his system with bcmgenet as DSA master and KSZ9897
as a switch, rebooting or shutting down never works properly.

What does the bcmgenet driver have special to trigger this, that other
DSA masters do not? It has an implementation of ->shutdown which simply
calls its ->remove implementation. Otherwise said, it unregisters its
network interface on shutdown.

This message can be seen in a loop, and it hangs the reboot process there:

unregister_netdevice: waiting for eth0 to become free. Usage count = 3

So why 3?

A usage count of 1 is normal for a registered network interface, and any
virtual interface which links itself as an upper of that will increment
it via dev_hold. In the case of DSA, this is the call path:

dsa_slave_create
-> netdev_upper_dev_link
   -> __netdev_upper_dev_link
      -> __netdev_adjacent_dev_insert
         -> dev_hold

So a DSA switch with 3 interfaces will result in a usage count elevated
by two, and netdev_wait_allrefs will wait until they have gone away.

Other stacked interfaces, like VLAN, watch NETDEV_UNREGISTER events and
delete themselves, but DSA cannot just vanish and go poof, at most it
can unbind itself from the switch devices, but that must happen strictly
earlier compared to when the DSA master unregisters its net_device, so
reacting on the NETDEV_UNREGISTER event is way too late.

It seems that it is a pretty established pattern to have a driver's
->shutdown hook redirect to its ->remove hook, so the same code is
executed regardless of whether the driver is unbound from the device, or
the system is just shutting down. As Florian puts it, it is quite a big
hammer for bcmgenet to unregister its net_device during shutdown, but
having a common code path with the driver unbind helps ensure it is well
tested.

So DSA, for better or for worse, has to live with that and engage in an
arms race of implementing the ->shutdown hook too, from all individual
drivers, and do something sane when paired with masters that unregister
their net_device there. The only sane thing to do, of course, is to
unlink from the master.

However, complications arise really quickly.

The pattern of redirecting ->shutdown to ->remove is not unique to
bcmgenet or even to net_device drivers. In fact, SPI controllers do it
too (see dspi_shutdown -> dspi_remove), and presumably, I2C controllers
and MDIO controllers do it too (this is something I have not researched
too deeply, but even if this is not the case today, it is certainly
plausible to happen in the future, and must be taken into consideration).

Since DSA switches might be SPI devices, I2C devices, MDIO devices, the
insane implication is that for the exact same DSA switch device, we
might have both ->shutdown and ->remove getting called.

So we need to do something with that insane environment. The pattern
I've come up with is "if this, then not that", so if either ->shutdown
or ->remove gets called, we set the device's drvdata to NULL, and in the
other hook, we check whether the drvdata is NULL and just do nothing.
This is probably not necessary for platform devices, just for devices on
buses, but I would really insist for consistency among drivers, because
when code is copy-pasted, it is not always copy-pasted from the best
sources.

So depending on whether the DSA switch's ->remove or ->shutdown will get
called first, we cannot really guarantee even for the same driver if
rebooting will result in the same code path on all platforms. But
nonetheless, we need to do something minimally reasonable on ->shutdown
too to fix the bug. Of course, the ->remove will do more (a full
teardown of the tree, with all data structures freed, and this is why
the bug was not caught for so long). The new ->shutdown method is kept
separate from dsa_unregister_switch not because we couldn't have
unregistered the switch, but simply in the interest of doing something
quick and to the point.

The big question is: does the DSA switch's ->shutdown get called earlier
than the DSA master's ->shutdown? If not, there is still a risk that we
might still trigger the WARN_ON in unregister_netdevice that says we are
attempting to unregister a net_device which has uppers. That's no good.
Although the reference to the master net_device won't physically go away
even if DSA's ->shutdown comes afterwards, remember we have a dev_hold
on it.

The answer to that question lies in this comment above device_link_add:

 * A side effect of the link creation is re-ordering of dpm_list and the
 * devices_kset list by moving the consumer device and all devices depending
 * on it to the ends of these lists (that does not happen to devices that have
 * not been registered when this function is called).

so the fact that DSA uses device_link_add towards its master is not
exactly for nothing. device_shutdown() walks devices_kset from the back,
so this is our guarantee that DSA's shutdown happens before the master's
shutdown.

Fixes: 2f1e8ea726 ("net: dsa: link interfaces with the DSA master to get rid of lockdep warnings")
Link: https://lore.kernel.org/netdev/20210909095324.12978-1-LinoSanfilippo@gmx.de/
Reported-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-19 12:08:37 +01:00

389 lines
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/*
* B53 common definitions
*
* Copyright (C) 2011-2013 Jonas Gorski <jogo@openwrt.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#ifndef __B53_PRIV_H
#define __B53_PRIV_H
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/phy.h>
#include <linux/etherdevice.h>
#include <net/dsa.h>
#include "b53_regs.h"
struct b53_device;
struct net_device;
struct phylink_link_state;
struct b53_io_ops {
int (*read8)(struct b53_device *dev, u8 page, u8 reg, u8 *value);
int (*read16)(struct b53_device *dev, u8 page, u8 reg, u16 *value);
int (*read32)(struct b53_device *dev, u8 page, u8 reg, u32 *value);
int (*read48)(struct b53_device *dev, u8 page, u8 reg, u64 *value);
int (*read64)(struct b53_device *dev, u8 page, u8 reg, u64 *value);
int (*write8)(struct b53_device *dev, u8 page, u8 reg, u8 value);
int (*write16)(struct b53_device *dev, u8 page, u8 reg, u16 value);
int (*write32)(struct b53_device *dev, u8 page, u8 reg, u32 value);
int (*write48)(struct b53_device *dev, u8 page, u8 reg, u64 value);
int (*write64)(struct b53_device *dev, u8 page, u8 reg, u64 value);
int (*phy_read16)(struct b53_device *dev, int addr, int reg, u16 *value);
int (*phy_write16)(struct b53_device *dev, int addr, int reg, u16 value);
int (*irq_enable)(struct b53_device *dev, int port);
void (*irq_disable)(struct b53_device *dev, int port);
u8 (*serdes_map_lane)(struct b53_device *dev, int port);
int (*serdes_link_state)(struct b53_device *dev, int port,
struct phylink_link_state *state);
void (*serdes_config)(struct b53_device *dev, int port,
unsigned int mode,
const struct phylink_link_state *state);
void (*serdes_an_restart)(struct b53_device *dev, int port);
void (*serdes_link_set)(struct b53_device *dev, int port,
unsigned int mode, phy_interface_t interface,
bool link_up);
void (*serdes_phylink_validate)(struct b53_device *dev, int port,
unsigned long *supported,
struct phylink_link_state *state);
};
#define B53_INVALID_LANE 0xff
enum {
BCM4908_DEVICE_ID = 0x4908,
BCM5325_DEVICE_ID = 0x25,
BCM5365_DEVICE_ID = 0x65,
BCM5389_DEVICE_ID = 0x89,
BCM5395_DEVICE_ID = 0x95,
BCM5397_DEVICE_ID = 0x97,
BCM5398_DEVICE_ID = 0x98,
BCM53115_DEVICE_ID = 0x53115,
BCM53125_DEVICE_ID = 0x53125,
BCM53128_DEVICE_ID = 0x53128,
BCM63XX_DEVICE_ID = 0x6300,
BCM53010_DEVICE_ID = 0x53010,
BCM53011_DEVICE_ID = 0x53011,
BCM53012_DEVICE_ID = 0x53012,
BCM53018_DEVICE_ID = 0x53018,
BCM53019_DEVICE_ID = 0x53019,
BCM58XX_DEVICE_ID = 0x5800,
BCM583XX_DEVICE_ID = 0x58300,
BCM7445_DEVICE_ID = 0x7445,
BCM7278_DEVICE_ID = 0x7278,
};
#define B53_N_PORTS 9
#define B53_N_PORTS_25 6
struct b53_port {
u16 vlan_ctl_mask;
struct ethtool_eee eee;
};
struct b53_vlan {
u16 members;
u16 untag;
bool valid;
};
struct b53_device {
struct dsa_switch *ds;
struct b53_platform_data *pdata;
const char *name;
struct mutex reg_mutex;
struct mutex stats_mutex;
const struct b53_io_ops *ops;
/* chip specific data */
u32 chip_id;
u8 core_rev;
u8 vta_regs[3];
u8 duplex_reg;
u8 jumbo_pm_reg;
u8 jumbo_size_reg;
int reset_gpio;
u8 num_arl_bins;
u16 num_arl_buckets;
enum dsa_tag_protocol tag_protocol;
/* used ports mask */
u16 enabled_ports;
unsigned int imp_port;
unsigned int cpu_port;
/* connect specific data */
u8 current_page;
struct device *dev;
u8 serdes_lane;
/* Master MDIO bus we got probed from */
struct mii_bus *bus;
void *priv;
/* run time configuration */
bool enable_jumbo;
unsigned int num_vlans;
struct b53_vlan *vlans;
bool vlan_enabled;
unsigned int num_ports;
struct b53_port *ports;
};
#define b53_for_each_port(dev, i) \
for (i = 0; i < B53_N_PORTS; i++) \
if (dev->enabled_ports & BIT(i))
static inline int is5325(struct b53_device *dev)
{
return dev->chip_id == BCM5325_DEVICE_ID;
}
static inline int is5365(struct b53_device *dev)
{
#ifdef CONFIG_BCM47XX
return dev->chip_id == BCM5365_DEVICE_ID;
#else
return 0;
#endif
}
static inline int is5397_98(struct b53_device *dev)
{
return dev->chip_id == BCM5397_DEVICE_ID ||
dev->chip_id == BCM5398_DEVICE_ID;
}
static inline int is539x(struct b53_device *dev)
{
return dev->chip_id == BCM5395_DEVICE_ID ||
dev->chip_id == BCM5397_DEVICE_ID ||
dev->chip_id == BCM5398_DEVICE_ID;
}
static inline int is531x5(struct b53_device *dev)
{
return dev->chip_id == BCM53115_DEVICE_ID ||
dev->chip_id == BCM53125_DEVICE_ID ||
dev->chip_id == BCM53128_DEVICE_ID;
}
static inline int is63xx(struct b53_device *dev)
{
return dev->chip_id == BCM63XX_DEVICE_ID;
}
static inline int is5301x(struct b53_device *dev)
{
return dev->chip_id == BCM53010_DEVICE_ID ||
dev->chip_id == BCM53011_DEVICE_ID ||
dev->chip_id == BCM53012_DEVICE_ID ||
dev->chip_id == BCM53018_DEVICE_ID ||
dev->chip_id == BCM53019_DEVICE_ID;
}
static inline int is58xx(struct b53_device *dev)
{
return dev->chip_id == BCM58XX_DEVICE_ID ||
dev->chip_id == BCM583XX_DEVICE_ID ||
dev->chip_id == BCM7445_DEVICE_ID ||
dev->chip_id == BCM7278_DEVICE_ID;
}
#define B53_CPU_PORT_25 5
#define B53_CPU_PORT 8
static inline unsigned int b53_max_arl_entries(struct b53_device *dev)
{
return dev->num_arl_buckets * dev->num_arl_bins;
}
struct b53_device *b53_switch_alloc(struct device *base,
const struct b53_io_ops *ops,
void *priv);
int b53_switch_detect(struct b53_device *dev);
int b53_switch_register(struct b53_device *dev);
static inline void b53_switch_remove(struct b53_device *dev)
{
dsa_unregister_switch(dev->ds);
}
static inline void b53_switch_shutdown(struct b53_device *dev)
{
dsa_switch_shutdown(dev->ds);
}
#define b53_build_op(type_op_size, val_type) \
static inline int b53_##type_op_size(struct b53_device *dev, u8 page, \
u8 reg, val_type val) \
{ \
int ret; \
\
mutex_lock(&dev->reg_mutex); \
ret = dev->ops->type_op_size(dev, page, reg, val); \
mutex_unlock(&dev->reg_mutex); \
\
return ret; \
}
b53_build_op(read8, u8 *);
b53_build_op(read16, u16 *);
b53_build_op(read32, u32 *);
b53_build_op(read48, u64 *);
b53_build_op(read64, u64 *);
b53_build_op(write8, u8);
b53_build_op(write16, u16);
b53_build_op(write32, u32);
b53_build_op(write48, u64);
b53_build_op(write64, u64);
struct b53_arl_entry {
u16 port;
u8 mac[ETH_ALEN];
u16 vid;
u8 is_valid:1;
u8 is_age:1;
u8 is_static:1;
};
static inline void b53_arl_to_entry(struct b53_arl_entry *ent,
u64 mac_vid, u32 fwd_entry)
{
memset(ent, 0, sizeof(*ent));
ent->port = fwd_entry & ARLTBL_DATA_PORT_ID_MASK;
ent->is_valid = !!(fwd_entry & ARLTBL_VALID);
ent->is_age = !!(fwd_entry & ARLTBL_AGE);
ent->is_static = !!(fwd_entry & ARLTBL_STATIC);
u64_to_ether_addr(mac_vid, ent->mac);
ent->vid = mac_vid >> ARLTBL_VID_S;
}
static inline void b53_arl_from_entry(u64 *mac_vid, u32 *fwd_entry,
const struct b53_arl_entry *ent)
{
*mac_vid = ether_addr_to_u64(ent->mac);
*mac_vid |= (u64)(ent->vid & ARLTBL_VID_MASK) << ARLTBL_VID_S;
*fwd_entry = ent->port & ARLTBL_DATA_PORT_ID_MASK;
if (ent->is_valid)
*fwd_entry |= ARLTBL_VALID;
if (ent->is_static)
*fwd_entry |= ARLTBL_STATIC;
if (ent->is_age)
*fwd_entry |= ARLTBL_AGE;
}
#ifdef CONFIG_BCM47XX
#include <linux/bcm47xx_nvram.h>
#include <bcm47xx_board.h>
static inline int b53_switch_get_reset_gpio(struct b53_device *dev)
{
enum bcm47xx_board board = bcm47xx_board_get();
switch (board) {
case BCM47XX_BOARD_LINKSYS_WRT300NV11:
case BCM47XX_BOARD_LINKSYS_WRT310NV1:
return 8;
default:
return bcm47xx_nvram_gpio_pin("robo_reset");
}
}
#else
static inline int b53_switch_get_reset_gpio(struct b53_device *dev)
{
return -ENOENT;
}
#endif
/* Exported functions towards other drivers */
void b53_imp_vlan_setup(struct dsa_switch *ds, int cpu_port);
int b53_configure_vlan(struct dsa_switch *ds);
void b53_get_strings(struct dsa_switch *ds, int port, u32 stringset,
uint8_t *data);
void b53_get_ethtool_stats(struct dsa_switch *ds, int port, uint64_t *data);
int b53_get_sset_count(struct dsa_switch *ds, int port, int sset);
void b53_get_ethtool_phy_stats(struct dsa_switch *ds, int port, uint64_t *data);
int b53_br_join(struct dsa_switch *ds, int port, struct net_device *bridge);
void b53_br_leave(struct dsa_switch *ds, int port, struct net_device *bridge);
void b53_br_set_stp_state(struct dsa_switch *ds, int port, u8 state);
void b53_br_fast_age(struct dsa_switch *ds, int port);
int b53_br_flags_pre(struct dsa_switch *ds, int port,
struct switchdev_brport_flags flags,
struct netlink_ext_ack *extack);
int b53_br_flags(struct dsa_switch *ds, int port,
struct switchdev_brport_flags flags,
struct netlink_ext_ack *extack);
int b53_setup_devlink_resources(struct dsa_switch *ds);
void b53_port_event(struct dsa_switch *ds, int port);
void b53_phylink_validate(struct dsa_switch *ds, int port,
unsigned long *supported,
struct phylink_link_state *state);
int b53_phylink_mac_link_state(struct dsa_switch *ds, int port,
struct phylink_link_state *state);
void b53_phylink_mac_config(struct dsa_switch *ds, int port,
unsigned int mode,
const struct phylink_link_state *state);
void b53_phylink_mac_an_restart(struct dsa_switch *ds, int port);
void b53_phylink_mac_link_down(struct dsa_switch *ds, int port,
unsigned int mode,
phy_interface_t interface);
void b53_phylink_mac_link_up(struct dsa_switch *ds, int port,
unsigned int mode,
phy_interface_t interface,
struct phy_device *phydev,
int speed, int duplex,
bool tx_pause, bool rx_pause);
int b53_vlan_filtering(struct dsa_switch *ds, int port, bool vlan_filtering,
struct netlink_ext_ack *extack);
int b53_vlan_add(struct dsa_switch *ds, int port,
const struct switchdev_obj_port_vlan *vlan,
struct netlink_ext_ack *extack);
int b53_vlan_del(struct dsa_switch *ds, int port,
const struct switchdev_obj_port_vlan *vlan);
int b53_fdb_add(struct dsa_switch *ds, int port,
const unsigned char *addr, u16 vid);
int b53_fdb_del(struct dsa_switch *ds, int port,
const unsigned char *addr, u16 vid);
int b53_fdb_dump(struct dsa_switch *ds, int port,
dsa_fdb_dump_cb_t *cb, void *data);
int b53_mdb_add(struct dsa_switch *ds, int port,
const struct switchdev_obj_port_mdb *mdb);
int b53_mdb_del(struct dsa_switch *ds, int port,
const struct switchdev_obj_port_mdb *mdb);
int b53_mirror_add(struct dsa_switch *ds, int port,
struct dsa_mall_mirror_tc_entry *mirror, bool ingress);
enum dsa_tag_protocol b53_get_tag_protocol(struct dsa_switch *ds, int port,
enum dsa_tag_protocol mprot);
void b53_mirror_del(struct dsa_switch *ds, int port,
struct dsa_mall_mirror_tc_entry *mirror);
int b53_enable_port(struct dsa_switch *ds, int port, struct phy_device *phy);
void b53_disable_port(struct dsa_switch *ds, int port);
void b53_brcm_hdr_setup(struct dsa_switch *ds, int port);
void b53_eee_enable_set(struct dsa_switch *ds, int port, bool enable);
int b53_eee_init(struct dsa_switch *ds, int port, struct phy_device *phy);
int b53_get_mac_eee(struct dsa_switch *ds, int port, struct ethtool_eee *e);
int b53_set_mac_eee(struct dsa_switch *ds, int port, struct ethtool_eee *e);
#endif
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