From 8eed01b5ca9c1deff329ad44f08e2041ca14842c Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Mon, 18 Jan 2021 16:06:55 +0100 Subject: [PATCH 1/2] mdio-bitbang: Export mdiobb_{read,write}() Export mdiobb_read() and mdiobb_write(), so Ethernet controller drivers can call them from their MDIO read/write wrappers. Signed-off-by: Geert Uytterhoeven Tested-by: Wolfram Sang Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- drivers/net/mdio/mdio-bitbang.c | 6 ++++-- include/linux/mdio-bitbang.h | 3 +++ 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/net/mdio/mdio-bitbang.c b/drivers/net/mdio/mdio-bitbang.c index 5136275c8e73..d3915f831854 100644 --- a/drivers/net/mdio/mdio-bitbang.c +++ b/drivers/net/mdio/mdio-bitbang.c @@ -149,7 +149,7 @@ static int mdiobb_cmd_addr(struct mdiobb_ctrl *ctrl, int phy, u32 addr) return dev_addr; } -static int mdiobb_read(struct mii_bus *bus, int phy, int reg) +int mdiobb_read(struct mii_bus *bus, int phy, int reg) { struct mdiobb_ctrl *ctrl = bus->priv; int ret, i; @@ -180,8 +180,9 @@ static int mdiobb_read(struct mii_bus *bus, int phy, int reg) mdiobb_get_bit(ctrl); return ret; } +EXPORT_SYMBOL(mdiobb_read); -static int mdiobb_write(struct mii_bus *bus, int phy, int reg, u16 val) +int mdiobb_write(struct mii_bus *bus, int phy, int reg, u16 val) { struct mdiobb_ctrl *ctrl = bus->priv; @@ -201,6 +202,7 @@ static int mdiobb_write(struct mii_bus *bus, int phy, int reg, u16 val) mdiobb_get_bit(ctrl); return 0; } +EXPORT_SYMBOL(mdiobb_write); struct mii_bus *alloc_mdio_bitbang(struct mdiobb_ctrl *ctrl) { diff --git a/include/linux/mdio-bitbang.h b/include/linux/mdio-bitbang.h index 5d71e8a8500f..aca4dc037b70 100644 --- a/include/linux/mdio-bitbang.h +++ b/include/linux/mdio-bitbang.h @@ -35,6 +35,9 @@ struct mdiobb_ctrl { const struct mdiobb_ops *ops; }; +int mdiobb_read(struct mii_bus *bus, int phy, int reg); +int mdiobb_write(struct mii_bus *bus, int phy, int reg, u16 val); + /* The returned bus is not yet registered with the phy layer. */ struct mii_bus *alloc_mdio_bitbang(struct mdiobb_ctrl *ctrl); From 02cae02a7de1484095e4ba984bfee7a75843ec26 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Mon, 18 Jan 2021 16:06:56 +0100 Subject: [PATCH 2/2] sh_eth: Make PHY access aware of Runtime PM to fix reboot crash Wolfram reports that his R-Car H2-based Lager board can no longer be rebooted in v5.11-rc1, as it crashes with an imprecise external abort. The issue can be reproduced on other boards (e.g. Koelsch with R-Car M2-W) too, if CONFIG_IP_PNP is disabled, and the Ethernet interface is down at reboot time: Unhandled fault: imprecise external abort (0x1406) at 0x00000000 pgd = (ptrval) [00000000] *pgd=422b6835, *pte=00000000, *ppte=00000000 Internal error: : 1406 [#1] ARM Modules linked in: CPU: 0 PID: 1105 Comm: init Tainted: G W 5.10.0-rc1-00402-ge2f016cf7751 #1048 Hardware name: Generic R-Car Gen2 (Flattened Device Tree) PC is at sh_mdio_ctrl+0x44/0x60 LR is at sh_mmd_ctrl+0x20/0x24 ... Backtrace: [] (sh_mdio_ctrl) from [] (sh_mmd_ctrl+0x20/0x24) r7:0000001f r6:00000020 r5:00000002 r4:c22a1dc4 [] (sh_mmd_ctrl) from [] (mdiobb_cmd+0x38/0xa8) [] (mdiobb_cmd) from [] (mdiobb_read+0x58/0xdc) r9:c229f844 r8:c0c329dc r7:c221e000 r6:00000001 r5:c22a1dc4 r4:00000001 [] (mdiobb_read) from [] (__mdiobus_read+0x74/0xe0) r7:0000001f r6:00000001 r5:c221e000 r4:c221e000 [] (__mdiobus_read) from [] (mdiobus_read+0x40/0x54) r7:0000001f r6:00000001 r5:c221e000 r4:c221e458 [] (mdiobus_read) from [] (phy_read+0x1c/0x20) r7:ffffe000 r6:c221e470 r5:00000200 r4:c229f800 [] (phy_read) from [] (kszphy_config_intr+0x44/0x80) [] (kszphy_config_intr) from [] (phy_disable_interrupts+0x44/0x50) r5:c229f800 r4:c229f800 [] (phy_disable_interrupts) from [] (phy_shutdown+0x18/0x1c) r5:c229f800 r4:c229f804 [] (phy_shutdown) from [] (device_shutdown+0x168/0x1f8) [] (device_shutdown) from [] (kernel_restart_prepare+0x3c/0x48) r9:c22d2000 r8:c0100264 r7:c0b0d034 r6:00000000 r5:4321fedc r4:00000000 [] (kernel_restart_prepare) from [] (kernel_restart+0x1c/0x60) [] (kernel_restart) from [] (__do_sys_reboot+0x168/0x208) r5:4321fedc r4:01234567 [] (__do_sys_reboot) from [] (sys_reboot+0x18/0x1c) r7:00000058 r6:00000000 r5:00000000 r4:00000000 [] (sys_reboot) from [] (ret_fast_syscall+0x0/0x54) As of commit e2f016cf775129c0 ("net: phy: add a shutdown procedure"), system reboot calls phy_disable_interrupts() during shutdown. As this happens unconditionally, the PHY registers may be accessed while the device is suspended, causing undefined behavior, which may crash the system. Fix this by wrapping the PHY bitbang accessors in the sh_eth driver by wrappers that take care of Runtime PM, to resume the device when needed. Reported-by: Wolfram Sang Suggested-by: Andrew Lunn Signed-off-by: Geert Uytterhoeven Tested-by: Wolfram Sang Reviewed-by: Florian Fainelli Reviewed-by: Andrew Lunn Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/renesas/sh_eth.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index c63304632935..9b52d350e21a 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -3034,6 +3034,28 @@ static int sh_mdio_release(struct sh_eth_private *mdp) return 0; } +static int sh_mdiobb_read(struct mii_bus *bus, int phy, int reg) +{ + int res; + + pm_runtime_get_sync(bus->parent); + res = mdiobb_read(bus, phy, reg); + pm_runtime_put(bus->parent); + + return res; +} + +static int sh_mdiobb_write(struct mii_bus *bus, int phy, int reg, u16 val) +{ + int res; + + pm_runtime_get_sync(bus->parent); + res = mdiobb_write(bus, phy, reg, val); + pm_runtime_put(bus->parent); + + return res; +} + /* MDIO bus init function */ static int sh_mdio_init(struct sh_eth_private *mdp, struct sh_eth_plat_data *pd) @@ -3058,6 +3080,10 @@ static int sh_mdio_init(struct sh_eth_private *mdp, if (!mdp->mii_bus) return -ENOMEM; + /* Wrap accessors with Runtime PM-aware ops */ + mdp->mii_bus->read = sh_mdiobb_read; + mdp->mii_bus->write = sh_mdiobb_write; + /* Hook up MII support for ethtool */ mdp->mii_bus->name = "sh_mii"; mdp->mii_bus->parent = dev;