// SPDX-License-Identifier: GPL-2.0
/*
 *   Copyright (C) 2000 Tilmann Bitterberg
 *   (tilmann@bitterberg.de)
 *
 *   RTAS (Runtime Abstraction Services) stuff
 *   Intention is to provide a clean user interface
 *   to use the RTAS.
 *
 *   TODO:
 *   Split off a header file and maybe move it to a different
 *   location. Write Documentation on what the /proc/rtas/ entries
 *   actually do.
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/ctype.h>
#include <linux/time.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/bitops.h>
#include <linux/rtc.h>
#include <linux/of.h>

#include <linux/uaccess.h>
#include <asm/processor.h>
#include <asm/io.h>
#include <asm/rtas.h>
#include <asm/machdep.h> /* for ppc_md */
#include <asm/time.h>

/* Token for Sensors */
#define KEY_SWITCH              0x0001
#define ENCLOSURE_SWITCH        0x0002
#define THERMAL_SENSOR          0x0003
#define LID_STATUS              0x0004
#define POWER_SOURCE            0x0005
#define BATTERY_VOLTAGE         0x0006
#define BATTERY_REMAINING       0x0007
#define BATTERY_PERCENTAGE      0x0008
#define EPOW_SENSOR             0x0009
#define BATTERY_CYCLESTATE      0x000a
#define BATTERY_CHARGING        0x000b

/* IBM specific sensors */
#define IBM_SURVEILLANCE        0x2328 /* 9000 */
#define IBM_FANRPM              0x2329 /* 9001 */
#define IBM_VOLTAGE             0x232a /* 9002 */
#define IBM_DRCONNECTOR         0x232b /* 9003 */
#define IBM_POWERSUPPLY         0x232c /* 9004 */

/* Status return values */
#define SENSOR_CRITICAL_HIGH    13
#define SENSOR_WARNING_HIGH     12
#define SENSOR_NORMAL           11
#define SENSOR_WARNING_LOW      10
#define SENSOR_CRITICAL_LOW      9
#define SENSOR_SUCCESS           0
#define SENSOR_HW_ERROR         -1
#define SENSOR_BUSY             -2
#define SENSOR_NOT_EXIST        -3
#define SENSOR_DR_ENTITY        -9000

/* Location Codes */
#define LOC_SCSI_DEV_ADDR       'A'
#define LOC_SCSI_DEV_LOC        'B'
#define LOC_CPU                 'C'
#define LOC_DISKETTE            'D'
#define LOC_ETHERNET            'E'
#define LOC_FAN                 'F'
#define LOC_GRAPHICS            'G'
/* reserved / not used          'H' */
#define LOC_IO_ADAPTER          'I'
/* reserved / not used          'J' */
#define LOC_KEYBOARD            'K'
#define LOC_LCD                 'L'
#define LOC_MEMORY              'M'
#define LOC_NV_MEMORY           'N'
#define LOC_MOUSE               'O'
#define LOC_PLANAR              'P'
#define LOC_OTHER_IO            'Q'
#define LOC_PARALLEL            'R'
#define LOC_SERIAL              'S'
#define LOC_DEAD_RING           'T'
#define LOC_RACKMOUNTED         'U' /* for _u_nit is rack mounted */
#define LOC_VOLTAGE             'V'
#define LOC_SWITCH_ADAPTER      'W'
#define LOC_OTHER               'X'
#define LOC_FIRMWARE            'Y'
#define LOC_SCSI                'Z'

/* Tokens for indicators */
#define TONE_FREQUENCY          0x0001 /* 0 - 1000 (HZ)*/
#define TONE_VOLUME             0x0002 /* 0 - 100 (%) */
#define SYSTEM_POWER_STATE      0x0003 
#define WARNING_LIGHT           0x0004
#define DISK_ACTIVITY_LIGHT     0x0005
#define HEX_DISPLAY_UNIT        0x0006
#define BATTERY_WARNING_TIME    0x0007
#define CONDITION_CYCLE_REQUEST 0x0008
#define SURVEILLANCE_INDICATOR  0x2328 /* 9000 */
#define DR_ACTION               0x2329 /* 9001 */
#define DR_INDICATOR            0x232a /* 9002 */
/* 9003 - 9004: Vendor specific */
/* 9006 - 9999: Vendor specific */

/* other */
#define MAX_SENSORS              17  /* I only know of 17 sensors */    
#define MAX_LINELENGTH          256
#define SENSOR_PREFIX           "ibm,sensor-"
#define cel_to_fahr(x)          ((x*9/5)+32)

struct individual_sensor {
        unsigned int token;
        unsigned int quant;
};

struct rtas_sensors {
        struct individual_sensor sensor[MAX_SENSORS];
        unsigned int quant;
};

/* Globals */
static struct rtas_sensors sensors;
static struct device_node *rtas_node = NULL;
static unsigned long power_on_time = 0; /* Save the time the user set */
static char progress_led[MAX_LINELENGTH];

static unsigned long rtas_tone_frequency = 1000;
static unsigned long rtas_tone_volume = 0;

/* ****************************************************************** */
/* Declarations */
static int ppc_rtas_sensors_show(struct seq_file *m, void *v);
static int ppc_rtas_clock_show(struct seq_file *m, void *v);
static ssize_t ppc_rtas_clock_write(struct file *file,
                const char __user *buf, size_t count, loff_t *ppos);
static int ppc_rtas_progress_show(struct seq_file *m, void *v);
static ssize_t ppc_rtas_progress_write(struct file *file,
                const char __user *buf, size_t count, loff_t *ppos);
static int ppc_rtas_poweron_show(struct seq_file *m, void *v);
static ssize_t ppc_rtas_poweron_write(struct file *file,
                const char __user *buf, size_t count, loff_t *ppos);

static ssize_t ppc_rtas_tone_freq_write(struct file *file,
                const char __user *buf, size_t count, loff_t *ppos);
static int ppc_rtas_tone_freq_show(struct seq_file *m, void *v);
static ssize_t ppc_rtas_tone_volume_write(struct file *file,
                const char __user *buf, size_t count, loff_t *ppos);
static int ppc_rtas_tone_volume_show(struct seq_file *m, void *v);
static int ppc_rtas_rmo_buf_show(struct seq_file *m, void *v);

static int poweron_open(struct inode *inode, struct file *file)
{
        return single_open(file, ppc_rtas_poweron_show, NULL);
}

static const struct proc_ops ppc_rtas_poweron_proc_ops = {
        .proc_open      = poweron_open,
        .proc_read      = seq_read,
        .proc_lseek     = seq_lseek,
        .proc_write     = ppc_rtas_poweron_write,
        .proc_release   = single_release,
};

static int progress_open(struct inode *inode, struct file *file)
{
        return single_open(file, ppc_rtas_progress_show, NULL);
}

static const struct proc_ops ppc_rtas_progress_proc_ops = {
        .proc_open      = progress_open,
        .proc_read      = seq_read,
        .proc_lseek     = seq_lseek,
        .proc_write     = ppc_rtas_progress_write,
        .proc_release   = single_release,
};

static int clock_open(struct inode *inode, struct file *file)
{
        return single_open(file, ppc_rtas_clock_show, NULL);
}

static const struct proc_ops ppc_rtas_clock_proc_ops = {
        .proc_open      = clock_open,
        .proc_read      = seq_read,
        .proc_lseek     = seq_lseek,
        .proc_write     = ppc_rtas_clock_write,
        .proc_release   = single_release,
};

static int tone_freq_open(struct inode *inode, struct file *file)
{
        return single_open(file, ppc_rtas_tone_freq_show, NULL);
}

static const struct proc_ops ppc_rtas_tone_freq_proc_ops = {
        .proc_open      = tone_freq_open,
        .proc_read      = seq_read,
        .proc_lseek     = seq_lseek,
        .proc_write     = ppc_rtas_tone_freq_write,
        .proc_release   = single_release,
};

static int tone_volume_open(struct inode *inode, struct file *file)
{
        return single_open(file, ppc_rtas_tone_volume_show, NULL);
}

static const struct proc_ops ppc_rtas_tone_volume_proc_ops = {
        .proc_open      = tone_volume_open,
        .proc_read      = seq_read,
        .proc_lseek     = seq_lseek,
        .proc_write     = ppc_rtas_tone_volume_write,
        .proc_release   = single_release,
};

static int ppc_rtas_find_all_sensors(void);
static void ppc_rtas_process_sensor(struct seq_file *m,
        struct individual_sensor *s, int state, int error, const char *loc);
static char *ppc_rtas_process_error(int error);
static void get_location_code(struct seq_file *m,
        struct individual_sensor *s, const char *loc);
static void check_location_string(struct seq_file *m, const char *c);
static void check_location(struct seq_file *m, const char *c);

static int __init proc_rtas_init(void)
{
        if (!machine_is(pseries))
                return -ENODEV;

        rtas_node = of_find_node_by_name(NULL, "rtas");
        if (rtas_node == NULL)
                return -ENODEV;

        proc_create("powerpc/rtas/progress", 0644, NULL,
                    &ppc_rtas_progress_proc_ops);
        proc_create("powerpc/rtas/clock", 0644, NULL,
                    &ppc_rtas_clock_proc_ops);
        proc_create("powerpc/rtas/poweron", 0644, NULL,
                    &ppc_rtas_poweron_proc_ops);
        proc_create_single("powerpc/rtas/sensors", 0444, NULL,
                        ppc_rtas_sensors_show);
        proc_create("powerpc/rtas/frequency", 0644, NULL,
                    &ppc_rtas_tone_freq_proc_ops);
        proc_create("powerpc/rtas/volume", 0644, NULL,
                    &ppc_rtas_tone_volume_proc_ops);
        proc_create_single("powerpc/rtas/rmo_buffer", 0400, NULL,
                        ppc_rtas_rmo_buf_show);
        return 0;
}

__initcall(proc_rtas_init);

static int parse_number(const char __user *p, size_t count, u64 *val)
{
        char buf[40];

        if (count > 39)
                return -EINVAL;

        if (copy_from_user(buf, p, count))
                return -EFAULT;

        buf[count] = 0;

        return kstrtoull(buf, 10, val);
}

/* ****************************************************************** */
/* POWER-ON-TIME                                                      */
/* ****************************************************************** */
static ssize_t ppc_rtas_poweron_write(struct file *file,
                const char __user *buf, size_t count, loff_t *ppos)
{
        struct rtc_time tm;
        time64_t nowtime;
        int error = parse_number(buf, count, &nowtime);
        if (error)
                return error;

        power_on_time = nowtime; /* save the time */

        rtc_time64_to_tm(nowtime, &tm);

        error = rtas_call(rtas_function_token(RTAS_FN_SET_TIME_FOR_POWER_ON), 7, 1, NULL,
                          tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
                          tm.tm_hour, tm.tm_min, tm.tm_sec, 0 /* nano */);
        if (error)
                printk(KERN_WARNING "error: setting poweron time returned: %s\n", 
                                ppc_rtas_process_error(error));
        return count;
}
/* ****************************************************************** */
static int ppc_rtas_poweron_show(struct seq_file *m, void *v)
{
        if (power_on_time == 0)
                seq_printf(m, "Power on time not set\n");
        else
                seq_printf(m, "%lu\n",power_on_time);
        return 0;
}

/* ****************************************************************** */
/* PROGRESS                                                           */
/* ****************************************************************** */
static ssize_t ppc_rtas_progress_write(struct file *file,
                const char __user *buf, size_t count, loff_t *ppos)
{
        unsigned long hex;

        if (count >= MAX_LINELENGTH)
                count = MAX_LINELENGTH -1;
        if (copy_from_user(progress_led, buf, count)) { /* save the string */
                return -EFAULT;
        }
        progress_led[count] = 0;

        /* Lets see if the user passed hexdigits */
        hex = simple_strtoul(progress_led, NULL, 10);

        rtas_progress ((char *)progress_led, hex);
        return count;

        /* clear the line */
        /* rtas_progress("                   ", 0xffff);*/
}
/* ****************************************************************** */
static int ppc_rtas_progress_show(struct seq_file *m, void *v)
{
        if (progress_led[0])
                seq_printf(m, "%s\n", progress_led);
        return 0;
}

/* ****************************************************************** */
/* CLOCK                                                              */
/* ****************************************************************** */
static ssize_t ppc_rtas_clock_write(struct file *file,
                const char __user *buf, size_t count, loff_t *ppos)
{
        struct rtc_time tm;
        time64_t nowtime;
        int error = parse_number(buf, count, &nowtime);
        if (error)
                return error;

        rtc_time64_to_tm(nowtime, &tm);
        error = rtas_call(rtas_function_token(RTAS_FN_SET_TIME_OF_DAY), 7, 1, NULL,
                          tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
                          tm.tm_hour, tm.tm_min, tm.tm_sec, 0);
        if (error)
                printk(KERN_WARNING "error: setting the clock returned: %s\n", 
                                ppc_rtas_process_error(error));
        return count;
}
/* ****************************************************************** */
static int ppc_rtas_clock_show(struct seq_file *m, void *v)
{
        int ret[8];
        int error = rtas_call(rtas_function_token(RTAS_FN_GET_TIME_OF_DAY), 0, 8, ret);

        if (error) {
                printk(KERN_WARNING "error: reading the clock returned: %s\n", 
                                ppc_rtas_process_error(error));
                seq_printf(m, "0");
        } else { 
                unsigned int year, mon, day, hour, min, sec;
                year = ret[0]; mon  = ret[1]; day  = ret[2];
                hour = ret[3]; min  = ret[4]; sec  = ret[5];
                seq_printf(m, "%lld\n",
                                mktime64(year, mon, day, hour, min, sec));
        }
        return 0;
}

/* ****************************************************************** */
/* SENSOR STUFF                                                       */
/* ****************************************************************** */
static int ppc_rtas_sensors_show(struct seq_file *m, void *v)
{
        int i,j;
        int state, error;
        int get_sensor_state = rtas_function_token(RTAS_FN_GET_SENSOR_STATE);

        seq_printf(m, "RTAS (RunTime Abstraction Services) Sensor Information\n");
        seq_printf(m, "Sensor\t\tValue\t\tCondition\tLocation\n");
        seq_printf(m, "********************************************************\n");

        if (ppc_rtas_find_all_sensors() != 0) {
                seq_printf(m, "\nNo sensors are available\n");
                return 0;
        }

        for (i=0; i<sensors.quant; i++) {
                struct individual_sensor *p = &sensors.sensor[i];
                char rstr[64];
                const char *loc;
                int llen, offs;

                sprintf (rstr, SENSOR_PREFIX"%04d", p->token);
                loc = of_get_property(rtas_node, rstr, &llen);

                /* A sensor may have multiple instances */
                for (j = 0, offs = 0; j <= p->quant; j++) {
                        error = rtas_call(get_sensor_state, 2, 2, &state, 
                                          p->token, j);

                        ppc_rtas_process_sensor(m, p, state, error, loc);
                        seq_putc(m, '\n');
                        if (loc) {
                                offs += strlen(loc) + 1;
                                loc += strlen(loc) + 1;
                                if (offs >= llen)
                                        loc = NULL;
                        }
                }
        }
        return 0;
}

/* ****************************************************************** */

static int ppc_rtas_find_all_sensors(void)
{
        const unsigned int *utmp;
        int len, i;

        utmp = of_get_property(rtas_node, "rtas-sensors", &len);
        if (utmp == NULL) {
                printk (KERN_ERR "error: could not get rtas-sensors\n");
                return 1;
        }

        sensors.quant = len / 8;      /* int + int */

        for (i=0; i<sensors.quant; i++) {
                sensors.sensor[i].token = *utmp++;
                sensors.sensor[i].quant = *utmp++;
        }
        return 0;
}

/* ****************************************************************** */
/*
 * Builds a string of what rtas returned
 */
static char *ppc_rtas_process_error(int error)
{
        switch (error) {
                case SENSOR_CRITICAL_HIGH:
                        return "(critical high)";
                case SENSOR_WARNING_HIGH:
                        return "(warning high)";
                case SENSOR_NORMAL:
                        return "(normal)";
                case SENSOR_WARNING_LOW:
                        return "(warning low)";
                case SENSOR_CRITICAL_LOW:
                        return "(critical low)";
                case SENSOR_SUCCESS:
                        return "(read ok)";
                case SENSOR_HW_ERROR:
                        return "(hardware error)";
                case SENSOR_BUSY:
                        return "(busy)";
                case SENSOR_NOT_EXIST:
                        return "(non existent)";
                case SENSOR_DR_ENTITY:
                        return "(dr entity removed)";
                default:
                        return "(UNKNOWN)";
        }
}

/* ****************************************************************** */
/*
 * Builds a string out of what the sensor said
 */

static void ppc_rtas_process_sensor(struct seq_file *m,
        struct individual_sensor *s, int state, int error, const char *loc)
{
        /* Defined return vales */
        const char * key_switch[]        = { "Off\t", "Normal\t", "Secure\t", 
                                                "Maintenance" };
        const char * enclosure_switch[]  = { "Closed", "Open" };
        const char * lid_status[]        = { " ", "Open", "Closed" };
        const char * power_source[]      = { "AC\t", "Battery", 
                                                "AC & Battery" };
        const char * battery_remaining[] = { "Very Low", "Low", "Mid", "High" };
        const char * epow_sensor[]       = { 
                "EPOW Reset", "Cooling warning", "Power warning",
                "System shutdown", "System halt", "EPOW main enclosure",
                "EPOW power off" };
        const char * battery_cyclestate[]  = { "None", "In progress", 
                                                "Requested" };
        const char * battery_charging[]    = { "Charging", "Discharging",
                                                "No current flow" };
        const char * ibm_drconnector[]     = { "Empty", "Present", "Unusable", 
                                                "Exchange" };

        int have_strings = 0;
        int num_states = 0;
        int temperature = 0;
        int unknown = 0;

        /* What kind of sensor do we have here? */
        
        switch (s->token) {
                case KEY_SWITCH:
                        seq_printf(m, "Key switch:\t");
                        num_states = sizeof(key_switch) / sizeof(char *);
                        if (state < num_states) {
                                seq_printf(m, "%s\t", key_switch[state]);
                                have_strings = 1;
                        }
                        break;
                case ENCLOSURE_SWITCH:
                        seq_printf(m, "Enclosure switch:\t");
                        num_states = sizeof(enclosure_switch) / sizeof(char *);
                        if (state < num_states) {
                                seq_printf(m, "%s\t", 
                                                enclosure_switch[state]);
                                have_strings = 1;
                        }
                        break;
                case THERMAL_SENSOR:
                        seq_printf(m, "Temp. (C/F):\t");
                        temperature = 1;
                        break;
                case LID_STATUS:
                        seq_printf(m, "Lid status:\t");
                        num_states = sizeof(lid_status) / sizeof(char *);
                        if (state < num_states) {
                                seq_printf(m, "%s\t", lid_status[state]);
                                have_strings = 1;
                        }
                        break;
                case POWER_SOURCE:
                        seq_printf(m, "Power source:\t");
                        num_states = sizeof(power_source) / sizeof(char *);
                        if (state < num_states) {
                                seq_printf(m, "%s\t", 
                                                power_source[state]);
                                have_strings = 1;
                        }
                        break;
                case BATTERY_VOLTAGE:
                        seq_printf(m, "Battery voltage:\t");
                        break;
                case BATTERY_REMAINING:
                        seq_printf(m, "Battery remaining:\t");
                        num_states = sizeof(battery_remaining) / sizeof(char *);
                        if (state < num_states)
                        {
                                seq_printf(m, "%s\t", 
                                                battery_remaining[state]);
                                have_strings = 1;
                        }
                        break;
                case BATTERY_PERCENTAGE:
                        seq_printf(m, "Battery percentage:\t");
                        break;
                case EPOW_SENSOR:
                        seq_printf(m, "EPOW Sensor:\t");
                        num_states = sizeof(epow_sensor) / sizeof(char *);
                        if (state < num_states) {
                                seq_printf(m, "%s\t", epow_sensor[state]);
                                have_strings = 1;
                        }
                        break;
                case BATTERY_CYCLESTATE:
                        seq_printf(m, "Battery cyclestate:\t");
                        num_states = sizeof(battery_cyclestate) / 
                                        sizeof(char *);
                        if (state < num_states) {
                                seq_printf(m, "%s\t", 
                                                battery_cyclestate[state]);
                                have_strings = 1;
                        }
                        break;
                case BATTERY_CHARGING:
                        seq_printf(m, "Battery Charging:\t");
                        num_states = sizeof(battery_charging) / sizeof(char *);
                        if (state < num_states) {
                                seq_printf(m, "%s\t", 
                                                battery_charging[state]);
                                have_strings = 1;
                        }
                        break;
                case IBM_SURVEILLANCE:
                        seq_printf(m, "Surveillance:\t");
                        break;
                case IBM_FANRPM:
                        seq_printf(m, "Fan (rpm):\t");
                        break;
                case IBM_VOLTAGE:
                        seq_printf(m, "Voltage (mv):\t");
                        break;
                case IBM_DRCONNECTOR:
                        seq_printf(m, "DR connector:\t");
                        num_states = sizeof(ibm_drconnector) / sizeof(char *);
                        if (state < num_states) {
                                seq_printf(m, "%s\t", 
                                                ibm_drconnector[state]);
                                have_strings = 1;
                        }
                        break;
                case IBM_POWERSUPPLY:
                        seq_printf(m, "Powersupply:\t");
                        break;
                default:
                        seq_printf(m,  "Unknown sensor (type %d), ignoring it\n",
                                        s->token);
                        unknown = 1;
                        have_strings = 1;
                        break;
        }
        if (have_strings == 0) {
                if (temperature) {
                        seq_printf(m, "%4d /%4d\t", state, cel_to_fahr(state));
                } else
                        seq_printf(m, "%10d\t", state);
        }
        if (unknown == 0) {
                seq_printf(m, "%s\t", ppc_rtas_process_error(error));
                get_location_code(m, s, loc);
        }
}

/* ****************************************************************** */

static void check_location(struct seq_file *m, const char *c)
{
        switch (c[0]) {
                case LOC_PLANAR:
                        seq_printf(m, "Planar #%c", c[1]);
                        break;
                case LOC_CPU:
                        seq_printf(m, "CPU #%c", c[1]);
                        break;
                case LOC_FAN:
                        seq_printf(m, "Fan #%c", c[1]);
                        break;
                case LOC_RACKMOUNTED:
                        seq_printf(m, "Rack #%c", c[1]);
                        break;
                case LOC_VOLTAGE:
                        seq_printf(m, "Voltage #%c", c[1]);
                        break;
                case LOC_LCD:
                        seq_printf(m, "LCD #%c", c[1]);
                        break;
                case '.':
                        seq_printf(m, "- %c", c[1]);
                        break;
                default:
                        seq_printf(m, "Unknown location");
                        break;
        }
}


/* ****************************************************************** */
/* 
 * Format: 
 * ${LETTER}${NUMBER}[[-/]${LETTER}${NUMBER} [ ... ] ]
 * the '.' may be an abbreviation
 */
static void check_location_string(struct seq_file *m, const char *c)
{
        while (*c) {
                if (isalpha(*c) || *c == '.')
                        check_location(m, c);
                else if (*c == '/' || *c == '-')
                        seq_printf(m, " at ");
                c++;
        }
}


/* ****************************************************************** */

static void get_location_code(struct seq_file *m, struct individual_sensor *s,
                const char *loc)
{
        if (!loc || !*loc) {
                seq_printf(m, "---");/* does not have a location */
        } else {
                check_location_string(m, loc);
        }
        seq_putc(m, ' ');
}
/* ****************************************************************** */
/* INDICATORS - Tone Frequency                                        */
/* ****************************************************************** */
static ssize_t ppc_rtas_tone_freq_write(struct file *file,
                const char __user *buf, size_t count, loff_t *ppos)
{
        u64 freq;
        int error = parse_number(buf, count, &freq);
        if (error)
                return error;

        rtas_tone_frequency = freq; /* save it for later */
        error = rtas_call(rtas_function_token(RTAS_FN_SET_INDICATOR), 3, 1, NULL,
                          TONE_FREQUENCY, 0, freq);
        if (error)
                printk(KERN_WARNING "error: setting tone frequency returned: %s\n", 
                                ppc_rtas_process_error(error));
        return count;
}
/* ****************************************************************** */
static int ppc_rtas_tone_freq_show(struct seq_file *m, void *v)
{
        seq_printf(m, "%lu\n", rtas_tone_frequency);
        return 0;
}
/* ****************************************************************** */
/* INDICATORS - Tone Volume                                           */
/* ****************************************************************** */
static ssize_t ppc_rtas_tone_volume_write(struct file *file,
                const char __user *buf, size_t count, loff_t *ppos)
{
        u64 volume;
        int error = parse_number(buf, count, &volume);
        if (error)
                return error;

        if (volume > 100)
                volume = 100;
        
        rtas_tone_volume = volume; /* save it for later */
        error = rtas_call(rtas_function_token(RTAS_FN_SET_INDICATOR), 3, 1, NULL,
                          TONE_VOLUME, 0, volume);
        if (error)
                printk(KERN_WARNING "error: setting tone volume returned: %s\n", 
                                ppc_rtas_process_error(error));
        return count;
}
/* ****************************************************************** */
static int ppc_rtas_tone_volume_show(struct seq_file *m, void *v)
{
        seq_printf(m, "%lu\n", rtas_tone_volume);
        return 0;
}

/**
 * ppc_rtas_rmo_buf_show() - Describe RTAS-addressable region for user space.
 * @m: seq_file output target.
 * @v: Unused.
 *
 * Base + size description of a range of RTAS-addressable memory set
 * aside for user space to use as work area(s) for certain RTAS
 * functions. User space accesses this region via /dev/mem. Apart from
 * security policies, the kernel does not arbitrate or serialize
 * access to this region, and user space must ensure that concurrent
 * users do not interfere with each other.
 */
static int ppc_rtas_rmo_buf_show(struct seq_file *m, void *v)
{
        seq_printf(m, "%016lx %x\n", rtas_rmo_buf, RTAS_USER_REGION_SIZE);
        return 0;
}