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628 lines
15 KiB
628 lines
15 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* FIXME: add wdrtas_get_status and wdrtas_get_boot_status as soon as |
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* RTAS calls are available |
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*/ |
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|
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/* |
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* RTAS watchdog driver |
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* |
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* (C) Copyright IBM Corp. 2005 |
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* device driver to exploit watchdog RTAS functions |
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* |
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* Authors : Utz Bacher <[email protected]> |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/fs.h> |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/miscdevice.h> |
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#include <linux/module.h> |
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#include <linux/notifier.h> |
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#include <linux/reboot.h> |
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#include <linux/types.h> |
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#include <linux/watchdog.h> |
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#include <linux/uaccess.h> |
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#include <asm/rtas.h> |
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#define WDRTAS_MAGIC_CHAR 42 |
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#define WDRTAS_SUPPORTED_MASK (WDIOF_SETTIMEOUT | \ |
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WDIOF_MAGICCLOSE) |
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MODULE_AUTHOR("Utz Bacher <[email protected]>"); |
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MODULE_DESCRIPTION("RTAS watchdog driver"); |
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MODULE_LICENSE("GPL"); |
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static bool wdrtas_nowayout = WATCHDOG_NOWAYOUT; |
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static atomic_t wdrtas_miscdev_open = ATOMIC_INIT(0); |
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static char wdrtas_expect_close; |
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static int wdrtas_interval; |
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#define WDRTAS_THERMAL_SENSOR 3 |
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static int wdrtas_token_get_sensor_state; |
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#define WDRTAS_SURVEILLANCE_IND 9000 |
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static int wdrtas_token_set_indicator; |
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#define WDRTAS_SP_SPI 28 |
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static int wdrtas_token_get_sp; |
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static int wdrtas_token_event_scan; |
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#define WDRTAS_DEFAULT_INTERVAL 300 |
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#define WDRTAS_LOGBUFFER_LEN 128 |
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static char wdrtas_logbuffer[WDRTAS_LOGBUFFER_LEN]; |
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/*** watchdog access functions */ |
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/** |
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* wdrtas_set_interval - sets the watchdog interval |
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* @interval: new interval |
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* |
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* returns 0 on success, <0 on failures |
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* |
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* wdrtas_set_interval sets the watchdog keepalive interval by calling the |
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* RTAS function set-indicator (surveillance). The unit of interval is |
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* seconds. |
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*/ |
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static int wdrtas_set_interval(int interval) |
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{ |
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long result; |
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static int print_msg = 10; |
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/* rtas uses minutes */ |
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interval = (interval + 59) / 60; |
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result = rtas_call(wdrtas_token_set_indicator, 3, 1, NULL, |
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WDRTAS_SURVEILLANCE_IND, 0, interval); |
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if (result < 0 && print_msg) { |
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pr_err("setting the watchdog to %i timeout failed: %li\n", |
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interval, result); |
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print_msg--; |
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} |
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return result; |
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} |
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#define WDRTAS_SP_SPI_LEN 4 |
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/** |
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* wdrtas_get_interval - returns the current watchdog interval |
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* @fallback_value: value (in seconds) to use, if the RTAS call fails |
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* |
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* returns the interval |
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* |
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* wdrtas_get_interval returns the current watchdog keepalive interval |
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* as reported by the RTAS function ibm,get-system-parameter. The unit |
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* of the return value is seconds. |
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*/ |
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static int wdrtas_get_interval(int fallback_value) |
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{ |
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long result; |
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char value[WDRTAS_SP_SPI_LEN]; |
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spin_lock(&rtas_data_buf_lock); |
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memset(rtas_data_buf, 0, WDRTAS_SP_SPI_LEN); |
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result = rtas_call(wdrtas_token_get_sp, 3, 1, NULL, |
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WDRTAS_SP_SPI, __pa(rtas_data_buf), |
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WDRTAS_SP_SPI_LEN); |
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memcpy(value, rtas_data_buf, WDRTAS_SP_SPI_LEN); |
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spin_unlock(&rtas_data_buf_lock); |
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if (value[0] != 0 || value[1] != 2 || value[3] != 0 || result < 0) { |
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pr_warn("could not get sp_spi watchdog timeout (%li). Continuing\n", |
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result); |
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return fallback_value; |
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} |
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/* rtas uses minutes */ |
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return ((int)value[2]) * 60; |
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} |
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/** |
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* wdrtas_timer_start - starts watchdog |
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* |
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* wdrtas_timer_start starts the watchdog by calling the RTAS function |
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* set-interval (surveillance) |
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*/ |
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static void wdrtas_timer_start(void) |
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{ |
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wdrtas_set_interval(wdrtas_interval); |
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} |
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/** |
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* wdrtas_timer_stop - stops watchdog |
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* |
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* wdrtas_timer_stop stops the watchdog timer by calling the RTAS function |
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* set-interval (surveillance) |
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*/ |
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static void wdrtas_timer_stop(void) |
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{ |
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wdrtas_set_interval(0); |
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} |
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/** |
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* wdrtas_timer_keepalive - resets watchdog timer to keep system alive |
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* |
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* wdrtas_timer_keepalive restarts the watchdog timer by calling the |
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* RTAS function event-scan and repeats these calls as long as there are |
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* events available. All events will be dumped. |
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*/ |
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static void wdrtas_timer_keepalive(void) |
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{ |
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long result; |
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do { |
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result = rtas_call(wdrtas_token_event_scan, 4, 1, NULL, |
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RTAS_EVENT_SCAN_ALL_EVENTS, 0, |
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(void *)__pa(wdrtas_logbuffer), |
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WDRTAS_LOGBUFFER_LEN); |
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if (result < 0) |
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pr_err("event-scan failed: %li\n", result); |
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if (result == 0) |
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print_hex_dump(KERN_INFO, "dumping event, data: ", |
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DUMP_PREFIX_OFFSET, 16, 1, |
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wdrtas_logbuffer, WDRTAS_LOGBUFFER_LEN, false); |
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} while (result == 0); |
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} |
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/** |
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* wdrtas_get_temperature - returns current temperature |
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* |
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* returns temperature or <0 on failures |
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* |
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* wdrtas_get_temperature returns the current temperature in Fahrenheit. It |
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* uses the RTAS call get-sensor-state, token 3 to do so |
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*/ |
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static int wdrtas_get_temperature(void) |
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{ |
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int result; |
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int temperature = 0; |
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result = rtas_get_sensor(WDRTAS_THERMAL_SENSOR, 0, &temperature); |
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if (result < 0) |
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pr_warn("reading the thermal sensor failed: %i\n", result); |
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else |
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temperature = ((temperature * 9) / 5) + 32; /* fahrenheit */ |
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return temperature; |
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} |
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/** |
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* wdrtas_get_status - returns the status of the watchdog |
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* |
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* returns a bitmask of defines WDIOF_... as defined in |
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* include/linux/watchdog.h |
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*/ |
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static int wdrtas_get_status(void) |
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{ |
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return 0; /* TODO */ |
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} |
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/** |
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* wdrtas_get_boot_status - returns the reason for the last boot |
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* |
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* returns a bitmask of defines WDIOF_... as defined in |
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* include/linux/watchdog.h, indicating why the watchdog rebooted the system |
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*/ |
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static int wdrtas_get_boot_status(void) |
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{ |
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return 0; /* TODO */ |
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} |
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/*** watchdog API and operations stuff */ |
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/* wdrtas_write - called when watchdog device is written to |
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* @file: file structure |
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* @buf: user buffer with data |
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* @len: amount to data written |
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* @ppos: position in file |
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* |
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* returns the number of successfully processed characters, which is always |
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* the number of bytes passed to this function |
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* |
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* wdrtas_write processes all the data given to it and looks for the magic |
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* character 'V'. This character allows the watchdog device to be closed |
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* properly. |
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*/ |
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static ssize_t wdrtas_write(struct file *file, const char __user *buf, |
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size_t len, loff_t *ppos) |
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{ |
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int i; |
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char c; |
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if (!len) |
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goto out; |
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if (!wdrtas_nowayout) { |
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wdrtas_expect_close = 0; |
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/* look for 'V' */ |
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for (i = 0; i < len; i++) { |
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if (get_user(c, buf + i)) |
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return -EFAULT; |
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/* allow to close device */ |
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if (c == 'V') |
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wdrtas_expect_close = WDRTAS_MAGIC_CHAR; |
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} |
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} |
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wdrtas_timer_keepalive(); |
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out: |
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return len; |
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} |
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/** |
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* wdrtas_ioctl - ioctl function for the watchdog device |
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* @file: file structure |
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* @cmd: command for ioctl |
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* @arg: argument pointer |
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* |
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* returns 0 on success, <0 on failure |
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* |
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* wdrtas_ioctl implements the watchdog API ioctls |
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*/ |
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static long wdrtas_ioctl(struct file *file, unsigned int cmd, |
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unsigned long arg) |
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{ |
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int __user *argp = (void __user *)arg; |
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int i; |
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static const struct watchdog_info wdinfo = { |
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.options = WDRTAS_SUPPORTED_MASK, |
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.firmware_version = 0, |
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.identity = "wdrtas", |
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}; |
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switch (cmd) { |
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case WDIOC_GETSUPPORT: |
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if (copy_to_user(argp, &wdinfo, sizeof(wdinfo))) |
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return -EFAULT; |
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return 0; |
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case WDIOC_GETSTATUS: |
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i = wdrtas_get_status(); |
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return put_user(i, argp); |
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case WDIOC_GETBOOTSTATUS: |
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i = wdrtas_get_boot_status(); |
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return put_user(i, argp); |
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case WDIOC_GETTEMP: |
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if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) |
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return -EOPNOTSUPP; |
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i = wdrtas_get_temperature(); |
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return put_user(i, argp); |
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case WDIOC_SETOPTIONS: |
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if (get_user(i, argp)) |
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return -EFAULT; |
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if (i & WDIOS_DISABLECARD) |
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wdrtas_timer_stop(); |
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if (i & WDIOS_ENABLECARD) { |
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wdrtas_timer_keepalive(); |
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wdrtas_timer_start(); |
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} |
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/* not implemented. Done by H8 |
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if (i & WDIOS_TEMPPANIC) { |
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} */ |
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return 0; |
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case WDIOC_KEEPALIVE: |
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wdrtas_timer_keepalive(); |
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return 0; |
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case WDIOC_SETTIMEOUT: |
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if (get_user(i, argp)) |
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return -EFAULT; |
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if (wdrtas_set_interval(i)) |
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return -EINVAL; |
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wdrtas_timer_keepalive(); |
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if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) |
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wdrtas_interval = i; |
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else |
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wdrtas_interval = wdrtas_get_interval(i); |
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fallthrough; |
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case WDIOC_GETTIMEOUT: |
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return put_user(wdrtas_interval, argp); |
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default: |
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return -ENOTTY; |
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} |
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} |
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/** |
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* wdrtas_open - open function of watchdog device |
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* @inode: inode structure |
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* @file: file structure |
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* |
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* returns 0 on success, -EBUSY if the file has been opened already, <0 on |
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* other failures |
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* |
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* function called when watchdog device is opened |
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*/ |
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static int wdrtas_open(struct inode *inode, struct file *file) |
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{ |
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/* only open once */ |
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if (atomic_inc_return(&wdrtas_miscdev_open) > 1) { |
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atomic_dec(&wdrtas_miscdev_open); |
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return -EBUSY; |
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} |
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wdrtas_timer_start(); |
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wdrtas_timer_keepalive(); |
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return stream_open(inode, file); |
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} |
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/** |
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* wdrtas_close - close function of watchdog device |
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* @inode: inode structure |
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* @file: file structure |
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* |
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* returns 0 on success |
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* |
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* close function. Always succeeds |
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*/ |
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static int wdrtas_close(struct inode *inode, struct file *file) |
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{ |
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/* only stop watchdog, if this was announced using 'V' before */ |
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if (wdrtas_expect_close == WDRTAS_MAGIC_CHAR) |
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wdrtas_timer_stop(); |
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else { |
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pr_warn("got unexpected close. Watchdog not stopped.\n"); |
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wdrtas_timer_keepalive(); |
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} |
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wdrtas_expect_close = 0; |
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atomic_dec(&wdrtas_miscdev_open); |
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return 0; |
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} |
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/** |
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* wdrtas_temp_read - gives back the temperature in fahrenheit |
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* @file: file structure |
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* @buf: user buffer |
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* @count: number of bytes to be read |
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* @ppos: position in file |
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* |
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* returns always 1 or -EFAULT in case of user space copy failures, <0 on |
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* other failures |
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* |
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* wdrtas_temp_read gives the temperature to the users by copying this |
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* value as one byte into the user space buffer. The unit is Fahrenheit... |
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*/ |
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static ssize_t wdrtas_temp_read(struct file *file, char __user *buf, |
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size_t count, loff_t *ppos) |
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{ |
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int temperature = 0; |
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temperature = wdrtas_get_temperature(); |
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if (temperature < 0) |
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return temperature; |
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if (copy_to_user(buf, &temperature, 1)) |
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return -EFAULT; |
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return 1; |
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} |
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/** |
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* wdrtas_temp_open - open function of temperature device |
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* @inode: inode structure |
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* @file: file structure |
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* |
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* returns 0 on success, <0 on failure |
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* |
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* function called when temperature device is opened |
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*/ |
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static int wdrtas_temp_open(struct inode *inode, struct file *file) |
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{ |
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return stream_open(inode, file); |
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} |
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/** |
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* wdrtas_temp_close - close function of temperature device |
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* @inode: inode structure |
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* @file: file structure |
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* |
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* returns 0 on success |
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* |
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* close function. Always succeeds |
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*/ |
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static int wdrtas_temp_close(struct inode *inode, struct file *file) |
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{ |
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return 0; |
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} |
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/** |
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* wdrtas_reboot - reboot notifier function |
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* @nb: notifier block structure |
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* @code: reboot code |
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* @ptr: unused |
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* |
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* returns NOTIFY_DONE |
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* |
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* wdrtas_reboot stops the watchdog in case of a reboot |
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*/ |
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static int wdrtas_reboot(struct notifier_block *this, |
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unsigned long code, void *ptr) |
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{ |
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if (code == SYS_DOWN || code == SYS_HALT) |
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wdrtas_timer_stop(); |
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return NOTIFY_DONE; |
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} |
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/*** initialization stuff */ |
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static const struct file_operations wdrtas_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.write = wdrtas_write, |
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.unlocked_ioctl = wdrtas_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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.open = wdrtas_open, |
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.release = wdrtas_close, |
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}; |
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static struct miscdevice wdrtas_miscdev = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &wdrtas_fops, |
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}; |
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static const struct file_operations wdrtas_temp_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.read = wdrtas_temp_read, |
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.open = wdrtas_temp_open, |
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.release = wdrtas_temp_close, |
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}; |
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static struct miscdevice wdrtas_tempdev = { |
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.minor = TEMP_MINOR, |
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.name = "temperature", |
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.fops = &wdrtas_temp_fops, |
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}; |
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static struct notifier_block wdrtas_notifier = { |
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.notifier_call = wdrtas_reboot, |
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}; |
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/** |
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* wdrtas_get_tokens - reads in RTAS tokens |
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* |
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* returns 0 on success, <0 on failure |
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* |
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* wdrtas_get_tokens reads in the tokens for the RTAS calls used in |
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* this watchdog driver. It tolerates, if "get-sensor-state" and |
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* "ibm,get-system-parameter" are not available. |
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*/ |
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static int wdrtas_get_tokens(void) |
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{ |
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wdrtas_token_get_sensor_state = rtas_token("get-sensor-state"); |
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if (wdrtas_token_get_sensor_state == RTAS_UNKNOWN_SERVICE) { |
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pr_warn("couldn't get token for get-sensor-state. Trying to continue without temperature support.\n"); |
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} |
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wdrtas_token_get_sp = rtas_token("ibm,get-system-parameter"); |
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if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) { |
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pr_warn("couldn't get token for ibm,get-system-parameter. Trying to continue with a default timeout value of %i seconds.\n", |
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WDRTAS_DEFAULT_INTERVAL); |
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} |
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wdrtas_token_set_indicator = rtas_token("set-indicator"); |
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if (wdrtas_token_set_indicator == RTAS_UNKNOWN_SERVICE) { |
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pr_err("couldn't get token for set-indicator. Terminating watchdog code.\n"); |
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return -EIO; |
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} |
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wdrtas_token_event_scan = rtas_token("event-scan"); |
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if (wdrtas_token_event_scan == RTAS_UNKNOWN_SERVICE) { |
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pr_err("couldn't get token for event-scan. Terminating watchdog code.\n"); |
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return -EIO; |
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} |
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return 0; |
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} |
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/** |
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* wdrtas_unregister_devs - unregisters the misc dev handlers |
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* |
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* wdrtas_register_devs unregisters the watchdog and temperature watchdog |
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* misc devs |
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*/ |
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static void wdrtas_unregister_devs(void) |
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{ |
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misc_deregister(&wdrtas_miscdev); |
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if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) |
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misc_deregister(&wdrtas_tempdev); |
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} |
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/** |
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* wdrtas_register_devs - registers the misc dev handlers |
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* |
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* returns 0 on success, <0 on failure |
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* |
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* wdrtas_register_devs registers the watchdog and temperature watchdog |
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* misc devs |
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*/ |
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static int wdrtas_register_devs(void) |
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{ |
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int result; |
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result = misc_register(&wdrtas_miscdev); |
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if (result) { |
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pr_err("couldn't register watchdog misc device. Terminating watchdog code.\n"); |
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return result; |
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} |
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if (wdrtas_token_get_sensor_state != RTAS_UNKNOWN_SERVICE) { |
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result = misc_register(&wdrtas_tempdev); |
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if (result) { |
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pr_warn("couldn't register watchdog temperature misc device. Continuing without temperature support.\n"); |
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wdrtas_token_get_sensor_state = RTAS_UNKNOWN_SERVICE; |
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} |
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} |
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return 0; |
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} |
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|
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/** |
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* wdrtas_init - init function of the watchdog driver |
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* |
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* returns 0 on success, <0 on failure |
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* |
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* registers the file handlers and the reboot notifier |
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*/ |
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static int __init wdrtas_init(void) |
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{ |
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if (wdrtas_get_tokens()) |
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return -ENODEV; |
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|
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if (wdrtas_register_devs()) |
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return -ENODEV; |
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|
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if (register_reboot_notifier(&wdrtas_notifier)) { |
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pr_err("could not register reboot notifier. Terminating watchdog code.\n"); |
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wdrtas_unregister_devs(); |
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return -ENODEV; |
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} |
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if (wdrtas_token_get_sp == RTAS_UNKNOWN_SERVICE) |
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wdrtas_interval = WDRTAS_DEFAULT_INTERVAL; |
|
else |
|
wdrtas_interval = wdrtas_get_interval(WDRTAS_DEFAULT_INTERVAL); |
|
|
|
return 0; |
|
} |
|
|
|
/** |
|
* wdrtas_exit - exit function of the watchdog driver |
|
* |
|
* unregisters the file handlers and the reboot notifier |
|
*/ |
|
static void __exit wdrtas_exit(void) |
|
{ |
|
if (!wdrtas_nowayout) |
|
wdrtas_timer_stop(); |
|
|
|
wdrtas_unregister_devs(); |
|
|
|
unregister_reboot_notifier(&wdrtas_notifier); |
|
} |
|
|
|
module_init(wdrtas_init); |
|
module_exit(wdrtas_exit);
|
|
|