dcdbas.c

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/*
 *  dcdbas.c: Dell Systems Management Base Driver
 *
 *  The Dell Systems Management Base Driver provides a sysfs interface for
 *  systems management software to perform System Management Interrupts (SMIs)
 *  and Host Control Actions (power cycle or power off after OS shutdown) on
 *  Dell systems.
 *
 *  See Documentation/dcdbas.txt for more information.
 *
 *  Copyright (C) 1995-2006 Dell Inc.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License v2.0 as published by
 *  the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 */

#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/errno.h>
#include <linux/gfp.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mc146818rtc.h>
#include <linux/module.h>
#include <linux/reboot.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <asm/io.h>

#include "dcdbas.h"

#define DRIVER_NAME     "dcdbas"
#define DRIVER_VERSION      "5.6.0-3.2"
#define DRIVER_DESCRIPTION  "Dell Systems Management Base Driver"

static struct platform_device *dcdbas_pdev;

static u8 *smi_data_buf;
static dma_addr_t smi_data_buf_handle;
static unsigned long smi_data_buf_size;
static u32 smi_data_buf_phys_addr;
static DEFINE_MUTEX(smi_data_lock);

static unsigned int host_control_action;
static unsigned int host_control_smi_type;
static unsigned int host_control_on_shutdown;

static void smi_data_buf_free(void)
{
    if (!smi_data_buf)
        return;

    dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
        __func__, smi_data_buf_phys_addr, smi_data_buf_size);

    dma_free_coherent(&dcdbas_pdev->dev, smi_data_buf_size, smi_data_buf,
              smi_data_buf_handle);
    smi_data_buf = NULL;
    smi_data_buf_handle = 0;
    smi_data_buf_phys_addr = 0;
    smi_data_buf_size = 0;
}

static int smi_data_buf_realloc(unsigned long size)
{
    void *buf;
    dma_addr_t handle;

    if (smi_data_buf_size >= size)
        return 0;

    if (size > MAX_SMI_DATA_BUF_SIZE)
        return -EINVAL;

    /* new buffer is needed */
    buf = dma_alloc_coherent(&dcdbas_pdev->dev, size, &handle, GFP_KERNEL);
    if (!buf) {
        dev_dbg(&dcdbas_pdev->dev,
            "%s: failed to allocate memory size %lu\n",
            __func__, size);
        return -ENOMEM;
    }
    /* memory zeroed by dma_alloc_coherent */

    if (smi_data_buf)
        memcpy(buf, smi_data_buf, smi_data_buf_size);

    /* free any existing buffer */
    smi_data_buf_free();

    /* set up new buffer for use */
    smi_data_buf = buf;
    smi_data_buf_handle = handle;
    smi_data_buf_phys_addr = (u32) virt_to_phys(buf);
    smi_data_buf_size = size;

    dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",
        __func__, smi_data_buf_phys_addr, smi_data_buf_size);

    return 0;
}

static ssize_t smi_data_buf_phys_addr_show(struct device *dev,
                       struct device_attribute *attr,
                       char *buf)
{
    return sprintf(buf, "%x\n", smi_data_buf_phys_addr);
}

static ssize_t smi_data_buf_size_show(struct device *dev,
                      struct device_attribute *attr,
                      char *buf)
{
    return sprintf(buf, "%lu\n", smi_data_buf_size);
}

static ssize_t smi_data_buf_size_store(struct device *dev,
                       struct device_attribute *attr,
                       const char *buf, size_t count)
{
    unsigned long buf_size;
    ssize_t ret;

    buf_size = simple_strtoul(buf, NULL, 10);

    /* make sure SMI data buffer is at least buf_size */
    mutex_lock(&smi_data_lock);
    ret = smi_data_buf_realloc(buf_size);
    mutex_unlock(&smi_data_lock);
    if (ret)
        return ret;

    return count;
}

static ssize_t smi_data_read(struct file *filp, struct kobject *kobj,
                 struct bin_attribute *bin_attr,
                 char *buf, loff_t pos, size_t count)
{
    ssize_t ret;

    mutex_lock(&smi_data_lock);
    ret = memory_read_from_buffer(buf, count, &pos, smi_data_buf,
                    smi_data_buf_size);
    mutex_unlock(&smi_data_lock);
    return ret;
}

static ssize_t smi_data_write(struct file *filp, struct kobject *kobj,
                  struct bin_attribute *bin_attr,
                  char *buf, loff_t pos, size_t count)
{
    ssize_t ret;

    if ((pos + count) > MAX_SMI_DATA_BUF_SIZE)
        return -EINVAL;

    mutex_lock(&smi_data_lock);

    ret = smi_data_buf_realloc(pos + count);
    if (ret)
        goto out;

    memcpy(smi_data_buf + pos, buf, count);
    ret = count;
out:
    mutex_unlock(&smi_data_lock);
    return ret;
}

static ssize_t host_control_action_show(struct device *dev,
                    struct device_attribute *attr,
                    char *buf)
{
    return sprintf(buf, "%u\n", host_control_action);
}

static ssize_t host_control_action_store(struct device *dev,
                     struct device_attribute *attr,
                     const char *buf, size_t count)
{
    ssize_t ret;

    /* make sure buffer is available for host control command */
    mutex_lock(&smi_data_lock);
    ret = smi_data_buf_realloc(sizeof(struct apm_cmd));
    mutex_unlock(&smi_data_lock);
    if (ret)
        return ret;

    host_control_action = simple_strtoul(buf, NULL, 10);
    return count;
}

static ssize_t host_control_smi_type_show(struct device *dev,
                      struct device_attribute *attr,
                      char *buf)
{
    return sprintf(buf, "%u\n", host_control_smi_type);
}

static ssize_t host_control_smi_type_store(struct device *dev,
                       struct device_attribute *attr,
                       const char *buf, size_t count)
{
    host_control_smi_type = simple_strtoul(buf, NULL, 10);
    return count;
}

static ssize_t host_control_on_shutdown_show(struct device *dev,
                         struct device_attribute *attr,
                         char *buf)
{
    return sprintf(buf, "%u\n", host_control_on_shutdown);
}

static ssize_t host_control_on_shutdown_store(struct device *dev,
                          struct device_attribute *attr,
                          const char *buf, size_t count)
{
    host_control_on_shutdown = simple_strtoul(buf, NULL, 10);
    return count;
}

int dcdbas_smi_request(struct smi_cmd *smi_cmd)
{
    cpumask_var_t old_mask;
    int ret = 0;

    if (smi_cmd->magic != SMI_CMD_MAGIC) {
        dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
             __func__);
        return -EBADR;
    }

    /* SMI requires CPU 0 */
    if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
        return -ENOMEM;

    cpumask_copy(old_mask, &current->cpus_allowed);
    set_cpus_allowed_ptr(current, cpumask_of(0));
    if (smp_processor_id() != 0) {
        dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n",
            __func__);
        ret = -EBUSY;
        goto out;
    }

    /* generate SMI */
    /* inb to force posted write through and make SMI happen now */
    asm volatile (
        "outb %b0,%w1\n"
        "inb %w1"
        : /* no output args */
        : "a" (smi_cmd->command_code),
          "d" (smi_cmd->command_address),
          "b" (smi_cmd->ebx),
          "c" (smi_cmd->ecx)
        : "memory"
    );

out:
    set_cpus_allowed_ptr(current, old_mask);
    free_cpumask_var(old_mask);
    return ret;
}

static ssize_t smi_request_store(struct device *dev,
                 struct device_attribute *attr,
                 const char *buf, size_t count)
{
    struct smi_cmd *smi_cmd;
    unsigned long val = simple_strtoul(buf, NULL, 10);
    ssize_t ret;

    mutex_lock(&smi_data_lock);

    if (smi_data_buf_size < sizeof(struct smi_cmd)) {
        ret = -ENODEV;
        goto out;
    }
    smi_cmd = (struct smi_cmd *)smi_data_buf;

    switch (val) {
    case 2:
        /* Raw SMI */
        ret = dcdbas_smi_request(smi_cmd);
        if (!ret)
            ret = count;
        break;
    case 1:
        /* Calling Interface SMI */
        smi_cmd->ebx = (u32) virt_to_phys(smi_cmd->command_buffer);
        ret = dcdbas_smi_request(smi_cmd);
        if (!ret)
            ret = count;
        break;
    case 0:
        memset(smi_data_buf, 0, smi_data_buf_size);
        ret = count;
        break;
    default:
        ret = -EINVAL;
        break;
    }

out:
    mutex_unlock(&smi_data_lock);
    return ret;
}
EXPORT_SYMBOL(dcdbas_smi_request);

static int host_control_smi(void)
{
    struct apm_cmd *apm_cmd;
    u8 *data;
    unsigned long flags;
    u32 num_ticks;
    s8 cmd_status;
    u8 index;

    apm_cmd = (struct apm_cmd *)smi_data_buf;
    apm_cmd->status = ESM_STATUS_CMD_UNSUCCESSFUL;

    switch (host_control_smi_type) {
    case HC_SMITYPE_TYPE1:
        spin_lock_irqsave(&rtc_lock, flags);
        /* write SMI data buffer physical address */
        data = (u8 *)&smi_data_buf_phys_addr;
        for (index = PE1300_CMOS_CMD_STRUCT_PTR;
             index < (PE1300_CMOS_CMD_STRUCT_PTR + 4);
             index++, data++) {
            outb(index,
                 (CMOS_BASE_PORT + CMOS_PAGE2_INDEX_PORT_PIIX4));
            outb(*data,
                 (CMOS_BASE_PORT + CMOS_PAGE2_DATA_PORT_PIIX4));
        }

        /* first set status to -1 as called by spec */
        cmd_status = ESM_STATUS_CMD_UNSUCCESSFUL;
        outb((u8) cmd_status, PCAT_APM_STATUS_PORT);

        /* generate SMM call */
        outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
        spin_unlock_irqrestore(&rtc_lock, flags);

        /* wait a few to see if it executed */
        num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
        while ((cmd_status = inb(PCAT_APM_STATUS_PORT))
               == ESM_STATUS_CMD_UNSUCCESSFUL) {
            num_ticks--;
            if (num_ticks == EXPIRED_TIMER)
                return -ETIME;
        }
        break;

    case HC_SMITYPE_TYPE2:
    case HC_SMITYPE_TYPE3:
        spin_lock_irqsave(&rtc_lock, flags);
        /* write SMI data buffer physical address */
        data = (u8 *)&smi_data_buf_phys_addr;
        for (index = PE1400_CMOS_CMD_STRUCT_PTR;
             index < (PE1400_CMOS_CMD_STRUCT_PTR + 4);
             index++, data++) {
            outb(index, (CMOS_BASE_PORT + CMOS_PAGE1_INDEX_PORT));
            outb(*data, (CMOS_BASE_PORT + CMOS_PAGE1_DATA_PORT));
        }

        /* generate SMM call */
        if (host_control_smi_type == HC_SMITYPE_TYPE3)
            outb(ESM_APM_CMD, PCAT_APM_CONTROL_PORT);
        else
            outb(ESM_APM_CMD, PE1400_APM_CONTROL_PORT);

        /* restore RTC index pointer since it was written to above */
        CMOS_READ(RTC_REG_C);
        spin_unlock_irqrestore(&rtc_lock, flags);

        /* read control port back to serialize write */
        cmd_status = inb(PE1400_APM_CONTROL_PORT);

        /* wait a few to see if it executed */
        num_ticks = TIMEOUT_USEC_SHORT_SEMA_BLOCKING;
        while (apm_cmd->status == ESM_STATUS_CMD_UNSUCCESSFUL) {
            num_ticks--;
            if (num_ticks == EXPIRED_TIMER)
                return -ETIME;
        }
        break;

    default:
        dev_dbg(&dcdbas_pdev->dev, "%s: invalid SMI type %u\n",
            __func__, host_control_smi_type);
        return -ENOSYS;
    }

    return 0;
}

static void dcdbas_host_control(void)
{
    struct apm_cmd *apm_cmd;
    u8 action;

    if (host_control_action == HC_ACTION_NONE)
        return;

    action = host_control_action;
    host_control_action = HC_ACTION_NONE;

    if (!smi_data_buf) {
        dev_dbg(&dcdbas_pdev->dev, "%s: no SMI buffer\n", __func__);
        return;
    }

    if (smi_data_buf_size < sizeof(struct apm_cmd)) {
        dev_dbg(&dcdbas_pdev->dev, "%s: SMI buffer too small\n",
            __func__);
        return;
    }

    apm_cmd = (struct apm_cmd *)smi_data_buf;

    /* power off takes precedence */
    if (action & HC_ACTION_HOST_CONTROL_POWEROFF) {
        apm_cmd->command = ESM_APM_POWER_CYCLE;
        apm_cmd->reserved = 0;
        *((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 0;
        host_control_smi();
    } else if (action & HC_ACTION_HOST_CONTROL_POWERCYCLE) {
        apm_cmd->command = ESM_APM_POWER_CYCLE;
        apm_cmd->reserved = 0;
        *((s16 *)&apm_cmd->parameters.shortreq.parm[0]) = (s16) 20;
        host_control_smi();
    }
}

static int dcdbas_reboot_notify(struct notifier_block *nb, unsigned long code,
                void *unused)
{
    switch (code) {
    case SYS_DOWN:
    case SYS_HALT:
    case SYS_POWER_OFF:
        if (host_control_on_shutdown) {
            /* firmware is going to perform host control action */
            printk(KERN_WARNING "Please wait for shutdown "
                   "action to complete...\n");
            dcdbas_host_control();
        }
        break;
    }

    return NOTIFY_DONE;
}

static struct notifier_block dcdbas_reboot_nb = {
    .notifier_call = dcdbas_reboot_notify,
    .next = NULL,
    .priority = INT_MIN
};

static DCDBAS_BIN_ATTR_RW(smi_data);

static struct bin_attribute *dcdbas_bin_attrs[] = {
    &bin_attr_smi_data,
    NULL
};

static DCDBAS_DEV_ATTR_RW(smi_data_buf_size);
static DCDBAS_DEV_ATTR_RO(smi_data_buf_phys_addr);
static DCDBAS_DEV_ATTR_WO(smi_request);
static DCDBAS_DEV_ATTR_RW(host_control_action);
static DCDBAS_DEV_ATTR_RW(host_control_smi_type);
static DCDBAS_DEV_ATTR_RW(host_control_on_shutdown);

static struct attribute *dcdbas_dev_attrs[] = {
    &dev_attr_smi_data_buf_size.attr,
    &dev_attr_smi_data_buf_phys_addr.attr,
    &dev_attr_smi_request.attr,
    &dev_attr_host_control_action.attr,
    &dev_attr_host_control_smi_type.attr,
    &dev_attr_host_control_on_shutdown.attr,
    NULL
};

static struct attribute_group dcdbas_attr_group = {
    .attrs = dcdbas_dev_attrs,
};

static int __devinit dcdbas_probe(struct platform_device *dev)
{
    int i, error;

    host_control_action = HC_ACTION_NONE;
    host_control_smi_type = HC_SMITYPE_NONE;

    /*
     * BIOS SMI calls require buffer addresses be in 32-bit address space.
     * This is done by setting the DMA mask below.
     */
    dcdbas_pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
    dcdbas_pdev->dev.dma_mask = &dcdbas_pdev->dev.coherent_dma_mask;

    error = sysfs_create_group(&dev->dev.kobj, &dcdbas_attr_group);
    if (error)
        return error;

    for (i = 0; dcdbas_bin_attrs[i]; i++) {
        error = sysfs_create_bin_file(&dev->dev.kobj,
                          dcdbas_bin_attrs[i]);
        if (error) {
            while (--i >= 0)
                sysfs_remove_bin_file(&dev->dev.kobj,
                              dcdbas_bin_attrs[i]);
            sysfs_remove_group(&dev->dev.kobj, &dcdbas_attr_group);
            return error;
        }
    }

    register_reboot_notifier(&dcdbas_reboot_nb);

    dev_info(&dev->dev, "%s (version %s)\n",
         DRIVER_DESCRIPTION, DRIVER_VERSION);

    return 0;
}

static int __devexit dcdbas_remove(struct platform_device *dev)
{
    int i;

    unregister_reboot_notifier(&dcdbas_reboot_nb);
    for (i = 0; dcdbas_bin_attrs[i]; i++)
        sysfs_remove_bin_file(&dev->dev.kobj, dcdbas_bin_attrs[i]);
    sysfs_remove_group(&dev->dev.kobj, &dcdbas_attr_group);

    return 0;
}

static struct platform_driver dcdbas_driver = {
    .driver     = {
        .name   = DRIVER_NAME,
        .owner  = THIS_MODULE,
    },
    .probe      = dcdbas_probe,
    .remove     = __devexit_p(dcdbas_remove),
};

static int __init dcdbas_init(void)
{
    int error;

    error = platform_driver_register(&dcdbas_driver);
    if (error)
        return error;

    dcdbas_pdev = platform_device_alloc(DRIVER_NAME, -1);
    if (!dcdbas_pdev) {
        error = -ENOMEM;
        goto err_unregister_driver;
    }

    error = platform_device_add(dcdbas_pdev);
    if (error)
        goto err_free_device;

    return 0;

 err_free_device:
    platform_device_put(dcdbas_pdev);
 err_unregister_driver:
    platform_driver_unregister(&dcdbas_driver);
    return error;
}

static void __exit dcdbas_exit(void)
{
    /*
     * make sure functions that use dcdbas_pdev are called
     * before platform_device_unregister
     */
    unregister_reboot_notifier(&dcdbas_reboot_nb);

    /*
     * We have to free the buffer here instead of dcdbas_remove
     * because only in module exit function we can be sure that
     * all sysfs attributes belonging to this module have been
     * released.
     */
    smi_data_buf_free();
    platform_device_unregister(dcdbas_pdev);
    platform_driver_unregister(&dcdbas_driver);
}

module_init(dcdbas_init);
module_exit(dcdbas_exit);

MODULE_DESCRIPTION(DRIVER_DESCRIPTION " (version " DRIVER_VERSION ")");
MODULE_VERSION(DRIVER_VERSION);
MODULE_AUTHOR("Dell Inc.");
MODULE_LICENSE("GPL");
/* Any System or BIOS claiming to be by Dell */
MODULE_ALIAS("dmi:*:[bs]vnD[Ee][Ll][Ll]*:*");