diff options
Diffstat (limited to 'drivers/net/dsa/mv88e6xxx/smi.c')
| -rw-r--r-- | drivers/net/dsa/mv88e6xxx/smi.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/drivers/net/dsa/mv88e6xxx/smi.c b/drivers/net/dsa/mv88e6xxx/smi.c new file mode 100644 index 000000000..a990271b7 --- /dev/null +++ b/drivers/net/dsa/mv88e6xxx/smi.c @@ -0,0 +1,190 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Marvell 88E6xxx System Management Interface (SMI) support + * + * Copyright (c) 2008 Marvell Semiconductor + * + * Copyright (c) 2019 Vivien Didelot <vivien.didelot@gmail.com> + */ + +#include "chip.h" +#include "smi.h" + +/* The switch ADDR[4:1] configuration pins define the chip SMI device address + * (ADDR[0] is always zero, thus only even SMI addresses can be strapped). + * + * When ADDR is all zero, the chip uses Single-chip Addressing Mode, assuming it + * is the only device connected to the SMI master. In this mode it responds to + * all 32 possible SMI addresses, and thus maps directly the internal devices. + * + * When ADDR is non-zero, the chip uses Multi-chip Addressing Mode, allowing + * multiple devices to share the SMI interface. In this mode it responds to only + * 2 registers, used to indirectly access the internal SMI devices. + * + * Some chips use a different scheme: Only the ADDR4 pin is used for + * configuration, and the device responds to 16 of the 32 SMI + * addresses, allowing two to coexist on the same SMI interface. + */ + +static int mv88e6xxx_smi_direct_read(struct mv88e6xxx_chip *chip, + int dev, int reg, u16 *data) +{ + int ret; + + ret = mdiobus_read_nested(chip->bus, dev, reg); + if (ret < 0) + return ret; + + *data = ret & 0xffff; + + return 0; +} + +static int mv88e6xxx_smi_direct_write(struct mv88e6xxx_chip *chip, + int dev, int reg, u16 data) +{ + int ret; + + ret = mdiobus_write_nested(chip->bus, dev, reg, data); + if (ret < 0) + return ret; + + return 0; +} + +static int mv88e6xxx_smi_direct_wait(struct mv88e6xxx_chip *chip, + int dev, int reg, int bit, int val) +{ + const unsigned long timeout = jiffies + msecs_to_jiffies(50); + u16 data; + int err; + int i; + + /* Even if the initial poll takes longer than 50ms, always do + * at least one more attempt. + */ + for (i = 0; time_before(jiffies, timeout) || (i < 2); i++) { + err = mv88e6xxx_smi_direct_read(chip, dev, reg, &data); + if (err) + return err; + + if (!!(data & BIT(bit)) == !!val) + return 0; + + if (i < 2) + cpu_relax(); + else + usleep_range(1000, 2000); + } + + return -ETIMEDOUT; +} + +static const struct mv88e6xxx_bus_ops mv88e6xxx_smi_direct_ops = { + .read = mv88e6xxx_smi_direct_read, + .write = mv88e6xxx_smi_direct_write, +}; + +static int mv88e6xxx_smi_dual_direct_read(struct mv88e6xxx_chip *chip, + int dev, int reg, u16 *data) +{ + return mv88e6xxx_smi_direct_read(chip, chip->sw_addr + dev, reg, data); +} + +static int mv88e6xxx_smi_dual_direct_write(struct mv88e6xxx_chip *chip, + int dev, int reg, u16 data) +{ + return mv88e6xxx_smi_direct_write(chip, chip->sw_addr + dev, reg, data); +} + +static const struct mv88e6xxx_bus_ops mv88e6xxx_smi_dual_direct_ops = { + .read = mv88e6xxx_smi_dual_direct_read, + .write = mv88e6xxx_smi_dual_direct_write, +}; + +/* Offset 0x00: SMI Command Register + * Offset 0x01: SMI Data Register + */ + +static int mv88e6xxx_smi_indirect_read(struct mv88e6xxx_chip *chip, + int dev, int reg, u16 *data) +{ + int err; + + err = mv88e6xxx_smi_direct_write(chip, chip->sw_addr, + MV88E6XXX_SMI_CMD, + MV88E6XXX_SMI_CMD_BUSY | + MV88E6XXX_SMI_CMD_MODE_22 | + MV88E6XXX_SMI_CMD_OP_22_READ | + (dev << 5) | reg); + if (err) + return err; + + err = mv88e6xxx_smi_direct_wait(chip, chip->sw_addr, + MV88E6XXX_SMI_CMD, 15, 0); + if (err) + return err; + + return mv88e6xxx_smi_direct_read(chip, chip->sw_addr, + MV88E6XXX_SMI_DATA, data); +} + +static int mv88e6xxx_smi_indirect_write(struct mv88e6xxx_chip *chip, + int dev, int reg, u16 data) +{ + int err; + + err = mv88e6xxx_smi_direct_write(chip, chip->sw_addr, + MV88E6XXX_SMI_DATA, data); + if (err) + return err; + + err = mv88e6xxx_smi_direct_write(chip, chip->sw_addr, + MV88E6XXX_SMI_CMD, + MV88E6XXX_SMI_CMD_BUSY | + MV88E6XXX_SMI_CMD_MODE_22 | + MV88E6XXX_SMI_CMD_OP_22_WRITE | + (dev << 5) | reg); + if (err) + return err; + + return mv88e6xxx_smi_direct_wait(chip, chip->sw_addr, + MV88E6XXX_SMI_CMD, 15, 0); +} + +static int mv88e6xxx_smi_indirect_init(struct mv88e6xxx_chip *chip) +{ + /* Ensure that the chip starts out in the ready state. As both + * reads and writes always ensure this on return, they can + * safely depend on the chip not being busy on entry. + */ + return mv88e6xxx_smi_direct_wait(chip, chip->sw_addr, + MV88E6XXX_SMI_CMD, 15, 0); +} + +static const struct mv88e6xxx_bus_ops mv88e6xxx_smi_indirect_ops = { + .read = mv88e6xxx_smi_indirect_read, + .write = mv88e6xxx_smi_indirect_write, + .init = mv88e6xxx_smi_indirect_init, +}; + +int mv88e6xxx_smi_init(struct mv88e6xxx_chip *chip, + struct mii_bus *bus, int sw_addr) +{ + if (chip->info->dual_chip) + chip->smi_ops = &mv88e6xxx_smi_dual_direct_ops; + else if (sw_addr == 0) + chip->smi_ops = &mv88e6xxx_smi_direct_ops; + else if (chip->info->multi_chip) + chip->smi_ops = &mv88e6xxx_smi_indirect_ops; + else + return -EINVAL; + + chip->bus = bus; + chip->sw_addr = sw_addr; + + if (chip->smi_ops->init) + return chip->smi_ops->init(chip); + + return 0; +} |