// SPDX-License-Identifier: GPL-2.0-or-later /*************************************************************************** * Copyright (C) 2010-2012 Hans de Goede * * * ***************************************************************************/ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include "sch56xx-common.h" /* Insmod parameters */ static int nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, int, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); #define SIO_SCH56XX_LD_EM 0x0C /* Embedded uController Logical Dev */ #define SIO_UNLOCK_KEY 0x55 /* Key to enable Super-I/O */ #define SIO_LOCK_KEY 0xAA /* Key to disable Super-I/O */ #define SIO_REG_LDSEL 0x07 /* Logical device select */ #define SIO_REG_DEVID 0x20 /* Device ID */ #define SIO_REG_ENABLE 0x30 /* Logical device enable */ #define SIO_REG_ADDR 0x66 /* Logical device address (2 bytes) */ #define SIO_SCH5627_ID 0xC6 /* Chipset ID */ #define SIO_SCH5636_ID 0xC7 /* Chipset ID */ #define REGION_LENGTH 10 #define SCH56XX_CMD_READ 0x02 #define SCH56XX_CMD_WRITE 0x03 /* Watchdog registers */ #define SCH56XX_REG_WDOG_PRESET 0x58B #define SCH56XX_REG_WDOG_CONTROL 0x58C #define SCH56XX_WDOG_TIME_BASE_SEC 0x01 #define SCH56XX_REG_WDOG_OUTPUT_ENABLE 0x58E #define SCH56XX_WDOG_OUTPUT_ENABLE 0x02 struct sch56xx_watchdog_data { u16 addr; struct mutex *io_lock; struct watchdog_info wdinfo; struct watchdog_device wddev; u8 watchdog_preset; u8 watchdog_control; u8 watchdog_output_enable; }; static struct platform_device *sch56xx_pdev; /* Super I/O functions */ static inline int superio_inb(int base, int reg) { outb(reg, base); return inb(base + 1); } static inline int superio_enter(int base) { /* Don't step on other drivers' I/O space by accident */ if (!request_muxed_region(base, 2, "sch56xx")) { pr_err("I/O address 0x%04x already in use\n", base); return -EBUSY; } outb(SIO_UNLOCK_KEY, base); return 0; } static inline void superio_select(int base, int ld) { outb(SIO_REG_LDSEL, base); outb(ld, base + 1); } static inline void superio_exit(int base) { outb(SIO_LOCK_KEY, base); release_region(base, 2); } static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v) { u8 val; int i; /* * According to SMSC for the commands we use the maximum time for * the EM to respond is 15 ms, but testing shows in practice it * responds within 15-32 reads, so we first busy poll, and if * that fails sleep a bit and try again until we are way past * the 15 ms maximum response time. */ const int max_busy_polls = 64; const int max_lazy_polls = 32; /* (Optional) Write-Clear the EC to Host Mailbox Register */ val = inb(addr + 1); outb(val, addr + 1); /* Set Mailbox Address Pointer to first location in Region 1 */ outb(0x00, addr + 2); outb(0x80, addr + 3); /* Write Request Packet Header */ outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */ outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */ outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */ /* Write Value field */ if (cmd == SCH56XX_CMD_WRITE) outb(v, addr + 4); /* Write Address field */ outb(reg & 0xff, addr + 6); outb(reg >> 8, addr + 7); /* Execute the Random Access Command */ outb(0x01, addr); /* Write 01h to the Host-to-EC register */ /* EM Interface Polling "Algorithm" */ for (i = 0; i < max_busy_polls + max_lazy_polls; i++) { if (i >= max_busy_polls) msleep(1); /* Read Interrupt source Register */ val = inb(addr + 8); /* Write Clear the interrupt source bits */ if (val) outb(val, addr + 8); /* Command Completed ? */ if (val & 0x01) break; } if (i == max_busy_polls + max_lazy_polls) { pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n", reg, 1); return -EIO; } /* * According to SMSC we may need to retry this, but sofar I've always * seen this succeed in 1 try. */ for (i = 0; i < max_busy_polls; i++) { /* Read EC-to-Host Register */ val = inb(addr + 1); /* Command Completed ? */ if (val == 0x01) break; if (i == 0) pr_warn("EC reports: 0x%02x reading virtual register 0x%04hx\n", (unsigned int)val, reg); } if (i == max_busy_polls) { pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n", reg, 2); return -EIO; } /* * According to the SMSC app note we should now do: * * Set Mailbox Address Pointer to first location in Region 1 * * outb(0x00, addr + 2); * outb(0x80, addr + 3); * * But if we do that things don't work, so let's not. */ /* Read Value field */ if (cmd == SCH56XX_CMD_READ) return inb(addr + 4); return 0; } int sch56xx_read_virtual_reg(u16 addr, u16 reg) { return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0); } EXPORT_SYMBOL(sch56xx_read_virtual_reg); int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val) { return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val); } EXPORT_SYMBOL(sch56xx_write_virtual_reg); int sch56xx_read_virtual_reg16(u16 addr, u16 reg) { int lsb, msb; /* Read LSB first, this will cause the matching MSB to be latched */ lsb = sch56xx_read_virtual_reg(addr, reg); if (lsb < 0) return lsb; msb = sch56xx_read_virtual_reg(addr, reg + 1); if (msb < 0) return msb; return lsb | (msb << 8); } EXPORT_SYMBOL(sch56xx_read_virtual_reg16); int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg, int high_nibble) { int msb, lsn; /* Read MSB first, this will cause the matching LSN to be latched */ msb = sch56xx_read_virtual_reg(addr, msb_reg); if (msb < 0) return msb; lsn = sch56xx_read_virtual_reg(addr, lsn_reg); if (lsn < 0) return lsn; if (high_nibble) return (msb << 4) | (lsn >> 4); else return (msb << 4) | (lsn & 0x0f); } EXPORT_SYMBOL(sch56xx_read_virtual_reg12); /* * Watchdog routines */ static int watchdog_set_timeout(struct watchdog_device *wddev, unsigned int timeout) { struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); unsigned int resolution; u8 control; int ret; /* 1 second or 60 second resolution? */ if (timeout <= 255) resolution = 1; else resolution = 60; if (timeout < resolution || timeout > (resolution * 255)) return -EINVAL; if (resolution == 1) control = data->watchdog_control | SCH56XX_WDOG_TIME_BASE_SEC; else control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC; if (data->watchdog_control != control) { mutex_lock(data->io_lock); ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_CONTROL, control); mutex_unlock(data->io_lock); if (ret) return ret; data->watchdog_control = control; } /* * Remember new timeout value, but do not write as that (re)starts * the watchdog countdown. */ data->watchdog_preset = DIV_ROUND_UP(timeout, resolution); wddev->timeout = data->watchdog_preset * resolution; return 0; } static int watchdog_start(struct watchdog_device *wddev) { struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); int ret; u8 val; /* * The sch56xx's watchdog cannot really be started / stopped * it is always running, but we can avoid the timer expiring * from causing a system reset by clearing the output enable bit. * * The sch56xx's watchdog will set the watchdog event bit, bit 0 * of the second interrupt source register (at base-address + 9), * when the timer expires. * * This will only cause a system reset if the 0-1 flank happens when * output enable is true. Setting output enable after the flank will * not cause a reset, nor will the timer expiring a second time. * This means we must clear the watchdog event bit in case it is set. * * The timer may still be running (after a recent watchdog_stop) and * mere milliseconds away from expiring, so the timer must be reset * first! */ mutex_lock(data->io_lock); /* 1. Reset the watchdog countdown counter */ ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET, data->watchdog_preset); if (ret) goto leave; /* 2. Enable output */ val = data->watchdog_output_enable | SCH56XX_WDOG_OUTPUT_ENABLE; ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE, val); if (ret) goto leave; data->watchdog_output_enable = val; /* 3. Clear the watchdog event bit if set */ val = inb(data->addr + 9); if (val & 0x01) outb(0x01, data->addr + 9); leave: mutex_unlock(data->io_lock); return ret; } static int watchdog_trigger(struct watchdog_device *wddev) { struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); int ret; /* Reset the watchdog countdown counter */ mutex_lock(data->io_lock); ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET, data->watchdog_preset); mutex_unlock(data->io_lock); return ret; } static int watchdog_stop(struct watchdog_device *wddev) { struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev); int ret = 0; u8 val; val = data->watchdog_output_enable & ~SCH56XX_WDOG_OUTPUT_ENABLE; mutex_lock(data->io_lock); ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE, val); mutex_unlock(data->io_lock); if (ret) return ret; data->watchdog_output_enable = val; return 0; } static const struct watchdog_ops watchdog_ops = { .owner = THIS_MODULE, .start = watchdog_start, .stop = watchdog_stop, .ping = watchdog_trigger, .set_timeout = watchdog_set_timeout, }; void sch56xx_watchdog_register(struct device *parent, u16 addr, u32 revision, struct mutex *io_lock, int check_enabled) { struct sch56xx_watchdog_data *data; int err, control, output_enable; /* Cache the watchdog registers */ mutex_lock(io_lock); control = sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL); output_enable = sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE); mutex_unlock(io_lock); if (control < 0) return; if (output_enable < 0) return; if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) { pr_warn("Watchdog not enabled by BIOS, not registering\n"); return; } data = devm_kzalloc(parent, sizeof(struct sch56xx_watchdog_data), GFP_KERNEL); if (!data) return; data->addr = addr; data->io_lock = io_lock; strlcpy(data->wdinfo.identity, "sch56xx watchdog", sizeof(data->wdinfo.identity)); data->wdinfo.firmware_version = revision; data->wdinfo.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT; if (!nowayout) data->wdinfo.options |= WDIOF_MAGICCLOSE; data->wddev.info = &data->wdinfo; data->wddev.ops = &watchdog_ops; data->wddev.parent = parent; data->wddev.timeout = 60; data->wddev.min_timeout = 1; data->wddev.max_timeout = 255 * 60; if (nowayout) set_bit(WDOG_NO_WAY_OUT, &data->wddev.status); if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE) set_bit(WDOG_ACTIVE, &data->wddev.status); /* Since the watchdog uses a downcounter there is no register to read the BIOS set timeout from (if any was set at all) -> Choose a preset which will give us a 1 minute timeout */ if (control & SCH56XX_WDOG_TIME_BASE_SEC) data->watchdog_preset = 60; /* seconds */ else data->watchdog_preset = 1; /* minute */ data->watchdog_control = control; data->watchdog_output_enable = output_enable; watchdog_set_drvdata(&data->wddev, data); err = devm_watchdog_register_device(parent, &data->wddev); if (err) { pr_err("Registering watchdog chardev: %d\n", err); devm_kfree(parent, data); } } EXPORT_SYMBOL(sch56xx_watchdog_register); /* * platform dev find, add and remove functions */ static int __init sch56xx_find(int sioaddr, const char **name) { u8 devid; unsigned short address; int err; err = superio_enter(sioaddr); if (err) return err; devid = superio_inb(sioaddr, SIO_REG_DEVID); switch (devid) { case SIO_SCH5627_ID: *name = "sch5627"; break; case SIO_SCH5636_ID: *name = "sch5636"; break; default: pr_debug("Unsupported device id: 0x%02x\n", (unsigned int)devid); err = -ENODEV; goto exit; } superio_select(sioaddr, SIO_SCH56XX_LD_EM); if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) { pr_warn("Device not activated\n"); err = -ENODEV; goto exit; } /* * Warning the order of the low / high byte is the other way around * as on most other superio devices!! */ address = superio_inb(sioaddr, SIO_REG_ADDR) | superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8; if (address == 0) { pr_warn("Base address not set\n"); err = -ENODEV; goto exit; } err = address; exit: superio_exit(sioaddr); return err; } static int __init sch56xx_device_add(int address, const char *name) { struct resource res = { .start = address, .end = address + REGION_LENGTH - 1, .flags = IORESOURCE_IO, }; int err; sch56xx_pdev = platform_device_alloc(name, address); if (!sch56xx_pdev) return -ENOMEM; res.name = sch56xx_pdev->name; err = acpi_check_resource_conflict(&res); if (err) goto exit_device_put; err = platform_device_add_resources(sch56xx_pdev, &res, 1); if (err) { pr_err("Device resource addition failed\n"); goto exit_device_put; } err = platform_device_add(sch56xx_pdev); if (err) { pr_err("Device addition failed\n"); goto exit_device_put; } return 0; exit_device_put: platform_device_put(sch56xx_pdev); return err; } static int __init sch56xx_init(void) { int address; const char *name = NULL; address = sch56xx_find(0x4e, &name); if (address < 0) address = sch56xx_find(0x2e, &name); if (address < 0) return address; return sch56xx_device_add(address, name); } static void __exit sch56xx_exit(void) { platform_device_unregister(sch56xx_pdev); } MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code"); MODULE_AUTHOR("Hans de Goede "); MODULE_LICENSE("GPL"); module_init(sch56xx_init); module_exit(sch56xx_exit);