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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/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 <asm/semaphore.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;

/**

 * smi_data_buf_free: free SMI data buffer

 */

static void smi_data_buf_free(void)

{

        if (!smi_data_buf)

                return;

        dev_dbg(&dcdbas_pdev->dev, "%s: phys: %x size: %lu\n",

                __FUNCTION__, 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;

}

/**

 * smi_data_buf_realloc: grow SMI data buffer if needed

 */

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",

                        __FUNCTION__, 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",

                __FUNCTION__, 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 kobject *kobj,

                             struct bin_attribute *bin_attr,

                             char *buf, loff_t pos, size_t count)

{

        size_t max_read;

        ssize_t ret;

        mutex_lock(&smi_data_lock);

        if (pos >= smi_data_buf_size) {

                ret = 0;

                goto out;

        }

        max_read = smi_data_buf_size - pos;

        ret = min(max_read, count);

        memcpy(buf, smi_data_buf + pos, ret);

out:

        mutex_unlock(&smi_data_lock);

        return ret;

}

static ssize_t smi_data_write(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;

}

/**

 * smi_request: generate SMI request

 *

 * Called with smi_data_lock.

 */

static int smi_request(struct smi_cmd *smi_cmd)

{

        cpumask_t old_mask;

        int ret = 0;

        if (smi_cmd->magic != SMI_CMD_MAGIC) {

                dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",

                         __FUNCTION__);

                return -EBADR;

        }

        /* SMI requires CPU 0 */

        old_mask = current->cpus_allowed;

        set_cpus_allowed(current, cpumask_of_cpu(0));

        if (smp_processor_id() != 0) {

                dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n",

                        __FUNCTION__);

                ret = -EBUSY;

                goto out;

        }

        /* generate SMI */

        asm volatile (

                "outb %b0,%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(current, old_mask);

        return ret;

}

/**

 * smi_request_store:

 *

 * The valid values are:

 * 0: zero SMI data buffer

 * 1: generate calling interface SMI

 * 2: generate raw SMI

 *

 * User application writes smi_cmd to smi_data before telling driver

 * to generate SMI.

 */

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 = 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 = 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;

}

/**

 * host_control_smi: generate host control SMI

 *

 * Caller must set up the host control command in smi_data_buf.

 */

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",

                        __FUNCTION__, host_control_smi_type);

                return -ENOSYS;

        }

        return 0;

}

/**

 * dcdbas_host_control: initiate host control

 *

 * This function is called by the driver after the system has

 * finished shutting down if the user application specified a

 * host control action to perform on shutdown.  It is safe to

 * use smi_data_buf at this point because the system has finished

 * shutting down and no userspace apps are running.

 */

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", __FUNCTION__);

                return;

        }

        if (smi_data_buf_size < sizeof(struct apm_cmd)) {

                dev_dbg(&dcdbas_pdev->dev, "%s: SMI buffer too small\n",

                        __FUNCTION__);

                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();

        }

}

/**

 * dcdbas_reboot_notify: handle reboot notification for host control

 */

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_32BIT_MASK;

        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),

};

/**

 * dcdbas_init: initialize driver

 */

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;

}

/**

 * dcdbas_exit: perform driver cleanup

 */

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);

        smi_data_buf_free();

        platform_device_unregister(dcdbas_pdev);

        platform_driver_unregister(&dcdbas_driver);

        /*

         * 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();

}

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");