dell_rbu.c

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/*
 * dell_rbu.c
 * Bios Update driver for Dell systems
 * Author: Dell Inc
 *         Abhay Salunke <[email protected]>
 *
 * Copyright (C) 2005 Dell Inc.
 *
 * Remote BIOS Update (rbu) driver is used for updating DELL BIOS by
 * creating entries in the /sys file systems on Linux 2.6 and higher
 * kernels. The driver supports two mechanism to update the BIOS namely
 * contiguous and packetized. Both these methods still require having some
 * application to set the CMOS bit indicating the BIOS to update itself
 * after a reboot.
 *
 * Contiguous method:
 * This driver writes the incoming data in a monolithic image by allocating
 * contiguous physical pages large enough to accommodate the incoming BIOS
 * image size.
 *
 * Packetized method:
 * The driver writes the incoming packet image by allocating a new packet
 * on every time the packet data is written. This driver requires an
 * application to break the BIOS image in to fixed sized packet chunks.
 *
 * See Documentation/dell_rbu.txt for more info.
 *
 * 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/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/blkdev.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/moduleparam.h>
#include <linux/firmware.h>
#include <linux/dma-mapping.h>

MODULE_AUTHOR("Abhay Salunke <[email protected]>");
MODULE_DESCRIPTION("Driver for updating BIOS image on DELL systems");
MODULE_LICENSE("GPL");
MODULE_VERSION("3.2");

#define BIOS_SCAN_LIMIT 0xffffffff
#define MAX_IMAGE_LENGTH 16
static struct _rbu_data {
    void *image_update_buffer;
    unsigned long image_update_buffer_size;
    unsigned long bios_image_size;
    int image_update_ordernum;
    int dma_alloc;
    spinlock_t lock;
    unsigned long packet_read_count;
    unsigned long num_packets;
    unsigned long packetsize;
    unsigned long imagesize;
    int entry_created;
} rbu_data;

static char image_type[MAX_IMAGE_LENGTH + 1] = "mono";
module_param_string(image_type, image_type, sizeof (image_type), 0);
MODULE_PARM_DESC(image_type,
    "BIOS image type. choose- mono or packet or init");

static unsigned long allocation_floor = 0x100000;
module_param(allocation_floor, ulong, 0644);
MODULE_PARM_DESC(allocation_floor,
    "Minimum address for allocations when using Packet mode");

struct packet_data {
    struct list_head list;
    size_t length;
    void *data;
    int ordernum;
};

static struct packet_data packet_data_head;

static struct platform_device *rbu_device;
static int context;
static dma_addr_t dell_rbu_dmaaddr;

static void init_packet_head(void)
{
    INIT_LIST_HEAD(&packet_data_head.list);
    rbu_data.packet_read_count = 0;
    rbu_data.num_packets = 0;
    rbu_data.packetsize = 0;
    rbu_data.imagesize = 0;
}

static int create_packet(void *data, size_t length)
{
    struct packet_data *newpacket;
    int ordernum = 0;
    int retval = 0;
    unsigned int packet_array_size = 0;
    void **invalid_addr_packet_array = NULL;
    void *packet_data_temp_buf = NULL;
    unsigned int idx = 0;

    pr_debug("create_packet: entry \n");

    if (!rbu_data.packetsize) {
        pr_debug("create_packet: packetsize not specified\n");
        retval = -EINVAL;
        goto out_noalloc;
    }

    spin_unlock(&rbu_data.lock);

    newpacket = kzalloc(sizeof (struct packet_data), GFP_KERNEL);

    if (!newpacket) {
        printk(KERN_WARNING
            "dell_rbu:%s: failed to allocate new "
            "packet\n", __func__);
        retval = -ENOMEM;
        spin_lock(&rbu_data.lock);
        goto out_noalloc;
    }

    ordernum = get_order(length);

    /*
     * BIOS errata mean we cannot allocate packets below 1MB or they will
     * be overwritten by BIOS.
     *
     * array to temporarily hold packets
     * that are below the allocation floor
     *
     * NOTE: very simplistic because we only need the floor to be at 1MB
     *       due to BIOS errata. This shouldn't be used for higher floors
     *       or you will run out of mem trying to allocate the array.
     */
    packet_array_size = max(
                (unsigned int)(allocation_floor / rbu_data.packetsize),
            (unsigned int)1);
    invalid_addr_packet_array = kzalloc(packet_array_size * sizeof(void*),
                        GFP_KERNEL);

    if (!invalid_addr_packet_array) {
        printk(KERN_WARNING
            "dell_rbu:%s: failed to allocate "
            "invalid_addr_packet_array \n",
            __func__);
        retval = -ENOMEM;
        spin_lock(&rbu_data.lock);
        goto out_alloc_packet;
    }

    while (!packet_data_temp_buf) {
        packet_data_temp_buf = (unsigned char *)
            __get_free_pages(GFP_KERNEL, ordernum);
        if (!packet_data_temp_buf) {
            printk(KERN_WARNING
                "dell_rbu:%s: failed to allocate new "
                "packet\n", __func__);
            retval = -ENOMEM;
            spin_lock(&rbu_data.lock);
            goto out_alloc_packet_array;
        }

        if ((unsigned long)virt_to_phys(packet_data_temp_buf)
                < allocation_floor) {
            pr_debug("packet 0x%lx below floor at 0x%lx.\n",
                    (unsigned long)virt_to_phys(
                        packet_data_temp_buf),
                    allocation_floor);
            invalid_addr_packet_array[idx++] = packet_data_temp_buf;
            packet_data_temp_buf = NULL;
        }
    }
    spin_lock(&rbu_data.lock);

    newpacket->data = packet_data_temp_buf;

    pr_debug("create_packet: newpacket at physical addr %lx\n",
        (unsigned long)virt_to_phys(newpacket->data));

    /* packets may not have fixed size */
    newpacket->length = length;
    newpacket->ordernum = ordernum;
    ++rbu_data.num_packets;

    /* initialize the newly created packet headers */
    INIT_LIST_HEAD(&newpacket->list);
    list_add_tail(&newpacket->list, &packet_data_head.list);

    memcpy(newpacket->data, data, length);

    pr_debug("create_packet: exit \n");

out_alloc_packet_array:
    /* always free packet array */
    for (;idx>0;idx--) {
        pr_debug("freeing unused packet below floor 0x%lx.\n",
            (unsigned long)virt_to_phys(
                invalid_addr_packet_array[idx-1]));
        free_pages((unsigned long)invalid_addr_packet_array[idx-1],
            ordernum);
    }
    kfree(invalid_addr_packet_array);

out_alloc_packet:
    /* if error, free data */
    if (retval)
        kfree(newpacket);

out_noalloc:
    return retval;
}

static int packetize_data(const u8 *data, size_t length)
{
    int rc = 0;
    int done = 0;
    int packet_length;
    u8 *temp;
    u8 *end = (u8 *) data + length;
    pr_debug("packetize_data: data length %zd\n", length);
    if (!rbu_data.packetsize) {
        printk(KERN_WARNING
            "dell_rbu: packetsize not specified\n");
        return -EIO;
    }

    temp = (u8 *) data;

    /* packetize the hunk */
    while (!done) {
        if ((temp + rbu_data.packetsize) < end)
            packet_length = rbu_data.packetsize;
        else {
            /* this is the last packet */
            packet_length = end - temp;
            done = 1;
        }

        if ((rc = create_packet(temp, packet_length)))
            return rc;

        pr_debug("%p:%td\n", temp, (end - temp));
        temp += packet_length;
    }

    rbu_data.imagesize = length;

    return rc;
}

static int do_packet_read(char *data, struct list_head *ptemp_list,
    int length, int bytes_read, int *list_read_count)
{
    void *ptemp_buf;
    struct packet_data *newpacket = NULL;
    int bytes_copied = 0;
    int j = 0;

    newpacket = list_entry(ptemp_list, struct packet_data, list);
    *list_read_count += newpacket->length;

    if (*list_read_count > bytes_read) {
        /* point to the start of unread data */
        j = newpacket->length - (*list_read_count - bytes_read);
        /* point to the offset in the packet buffer */
        ptemp_buf = (u8 *) newpacket->data + j;
        /*
         * check if there is enough room in
         * * the incoming buffer
         */
        if (length > (*list_read_count - bytes_read))
            /*
             * copy what ever is there in this
             * packet and move on
             */
            bytes_copied = (*list_read_count - bytes_read);
        else
            /* copy the remaining */
            bytes_copied = length;
        memcpy(data, ptemp_buf, bytes_copied);
    }
    return bytes_copied;
}

static int packet_read_list(char *data, size_t * pread_length)
{
    struct list_head *ptemp_list;
    int temp_count = 0;
    int bytes_copied = 0;
    int bytes_read = 0;
    int remaining_bytes = 0;
    char *pdest = data;

    /* check if we have any packets */
    if (0 == rbu_data.num_packets)
        return -ENOMEM;

    remaining_bytes = *pread_length;
    bytes_read = rbu_data.packet_read_count;

    ptemp_list = (&packet_data_head.list)->next;
    while (!list_empty(ptemp_list)) {
        bytes_copied = do_packet_read(pdest, ptemp_list,
            remaining_bytes, bytes_read, &temp_count);
        remaining_bytes -= bytes_copied;
        bytes_read += bytes_copied;
        pdest += bytes_copied;
        /*
         * check if we reached end of buffer before reaching the
         * last packet
         */
        if (remaining_bytes == 0)
            break;

        ptemp_list = ptemp_list->next;
    }
    /*finally set the bytes read */
    *pread_length = bytes_read - rbu_data.packet_read_count;
    rbu_data.packet_read_count = bytes_read;
    return 0;
}

static void packet_empty_list(void)
{
    struct list_head *ptemp_list;
    struct list_head *pnext_list;
    struct packet_data *newpacket;

    ptemp_list = (&packet_data_head.list)->next;
    while (!list_empty(ptemp_list)) {
        newpacket =
            list_entry(ptemp_list, struct packet_data, list);
        pnext_list = ptemp_list->next;
        list_del(ptemp_list);
        ptemp_list = pnext_list;
        /*
         * zero out the RBU packet memory before freeing
         * to make sure there are no stale RBU packets left in memory
         */
        memset(newpacket->data, 0, rbu_data.packetsize);
        free_pages((unsigned long) newpacket->data,
            newpacket->ordernum);
        kfree(newpacket);
    }
    rbu_data.packet_read_count = 0;
    rbu_data.num_packets = 0;
    rbu_data.imagesize = 0;
}

/*
 * img_update_free: Frees the buffer allocated for storing BIOS image
 * Always called with lock held and returned with lock held
 */
static void img_update_free(void)
{
    if (!rbu_data.image_update_buffer)
        return;
    /*
     * zero out this buffer before freeing it to get rid of any stale
     * BIOS image copied in memory.
     */
    memset(rbu_data.image_update_buffer, 0,
        rbu_data.image_update_buffer_size);
    if (rbu_data.dma_alloc == 1)
        dma_free_coherent(NULL, rbu_data.bios_image_size,
            rbu_data.image_update_buffer, dell_rbu_dmaaddr);
    else
        free_pages((unsigned long) rbu_data.image_update_buffer,
            rbu_data.image_update_ordernum);

    /*
     * Re-initialize the rbu_data variables after a free
     */
    rbu_data.image_update_ordernum = -1;
    rbu_data.image_update_buffer = NULL;
    rbu_data.image_update_buffer_size = 0;
    rbu_data.bios_image_size = 0;
    rbu_data.dma_alloc = 0;
}

/*
 * img_update_realloc: This function allocates the contiguous pages to
 * accommodate the requested size of data. The memory address and size
 * values are stored globally and on every call to this function the new
 * size is checked to see if more data is required than the existing size.
 * If true the previous memory is freed and new allocation is done to
 * accommodate the new size. If the incoming size is less then than the
 * already allocated size, then that memory is reused. This function is
 * called with lock held and returns with lock held.
 */
static int img_update_realloc(unsigned long size)
{
    unsigned char *image_update_buffer = NULL;
    unsigned long rc;
    unsigned long img_buf_phys_addr;
    int ordernum;
    int dma_alloc = 0;

    /*
     * check if the buffer of sufficient size has been
     * already allocated
     */
    if (rbu_data.image_update_buffer_size >= size) {
        /*
         * check for corruption
         */
        if ((size != 0) && (rbu_data.image_update_buffer == NULL)) {
            printk(KERN_ERR "dell_rbu:%s: corruption "
                "check failed\n", __func__);
            return -EINVAL;
        }
        /*
         * we have a valid pre-allocated buffer with
         * sufficient size
         */
        return 0;
    }

    /*
     * free any previously allocated buffer
     */
    img_update_free();

    spin_unlock(&rbu_data.lock);

    ordernum = get_order(size);
    image_update_buffer =
        (unsigned char *) __get_free_pages(GFP_KERNEL, ordernum);

    img_buf_phys_addr =
        (unsigned long) virt_to_phys(image_update_buffer);

    if (img_buf_phys_addr > BIOS_SCAN_LIMIT) {
        free_pages((unsigned long) image_update_buffer, ordernum);
        ordernum = -1;
        image_update_buffer = dma_alloc_coherent(NULL, size,
            &dell_rbu_dmaaddr, GFP_KERNEL);
        dma_alloc = 1;
    }

    spin_lock(&rbu_data.lock);

    if (image_update_buffer != NULL) {
        rbu_data.image_update_buffer = image_update_buffer;
        rbu_data.image_update_buffer_size = size;
        rbu_data.bios_image_size =
            rbu_data.image_update_buffer_size;
        rbu_data.image_update_ordernum = ordernum;
        rbu_data.dma_alloc = dma_alloc;
        rc = 0;
    } else {
        pr_debug("Not enough memory for image update:"
            "size = %ld\n", size);
        rc = -ENOMEM;
    }

    return rc;
}

static ssize_t read_packet_data(char *buffer, loff_t pos, size_t count)
{
    int retval;
    size_t bytes_left;
    size_t data_length;
    char *ptempBuf = buffer;

    /* check to see if we have something to return */
    if (rbu_data.num_packets == 0) {
        pr_debug("read_packet_data: no packets written\n");
        retval = -ENOMEM;
        goto read_rbu_data_exit;
    }

    if (pos > rbu_data.imagesize) {
        retval = 0;
        printk(KERN_WARNING "dell_rbu:read_packet_data: "
            "data underrun\n");
        goto read_rbu_data_exit;
    }

    bytes_left = rbu_data.imagesize - pos;
    data_length = min(bytes_left, count);

    if ((retval = packet_read_list(ptempBuf, &data_length)) < 0)
        goto read_rbu_data_exit;

    if ((pos + count) > rbu_data.imagesize) {
        rbu_data.packet_read_count = 0;
        /* this was the last copy */
        retval = bytes_left;
    } else
        retval = count;

      read_rbu_data_exit:
    return retval;
}

static ssize_t read_rbu_mono_data(char *buffer, loff_t pos, size_t count)
{
    /* check to see if we have something to return */
    if ((rbu_data.image_update_buffer == NULL) ||
        (rbu_data.bios_image_size == 0)) {
        pr_debug("read_rbu_data_mono: image_update_buffer %p ,"
            "bios_image_size %lu\n",
            rbu_data.image_update_buffer,
            rbu_data.bios_image_size);
        return -ENOMEM;
    }

    return memory_read_from_buffer(buffer, count, &pos,
            rbu_data.image_update_buffer, rbu_data.bios_image_size);
}

static ssize_t read_rbu_data(struct file *filp, struct kobject *kobj,
                 struct bin_attribute *bin_attr,
                 char *buffer, loff_t pos, size_t count)
{
    ssize_t ret_count = 0;

    spin_lock(&rbu_data.lock);

    if (!strcmp(image_type, "mono"))
        ret_count = read_rbu_mono_data(buffer, pos, count);
    else if (!strcmp(image_type, "packet"))
        ret_count = read_packet_data(buffer, pos, count);
    else
        pr_debug("read_rbu_data: invalid image type specified\n");

    spin_unlock(&rbu_data.lock);
    return ret_count;
}

static void callbackfn_rbu(const struct firmware *fw, void *context)
{
    rbu_data.entry_created = 0;

    if (!fw)
        return;

    if (!fw->size)
        goto out;

    spin_lock(&rbu_data.lock);
    if (!strcmp(image_type, "mono")) {
        if (!img_update_realloc(fw->size))
            memcpy(rbu_data.image_update_buffer,
                fw->data, fw->size);
    } else if (!strcmp(image_type, "packet")) {
        /*
         * we need to free previous packets if a
         * new hunk of packets needs to be downloaded
         */
        packet_empty_list();
        if (packetize_data(fw->data, fw->size))
            /* Incase something goes wrong when we are
             * in middle of packetizing the data, we
             * need to free up whatever packets might
             * have been created before we quit.
             */
            packet_empty_list();
    } else
        pr_debug("invalid image type specified.\n");
    spin_unlock(&rbu_data.lock);
 out:
    release_firmware(fw);
}

static ssize_t read_rbu_image_type(struct file *filp, struct kobject *kobj,
                   struct bin_attribute *bin_attr,
                   char *buffer, loff_t pos, size_t count)
{
    int size = 0;
    if (!pos)
        size = scnprintf(buffer, count, "%s\n", image_type);
    return size;
}

static ssize_t write_rbu_image_type(struct file *filp, struct kobject *kobj,
                    struct bin_attribute *bin_attr,
                    char *buffer, loff_t pos, size_t count)
{
    int rc = count;
    int req_firm_rc = 0;
    int i;
    spin_lock(&rbu_data.lock);
    /*
     * Find the first newline or space
     */
    for (i = 0; i < count; ++i)
        if (buffer[i] == '\n' || buffer[i] == ' ') {
            buffer[i] = '\0';
            break;
        }
    if (i == count)
        buffer[count] = '\0';

    if (strstr(buffer, "mono"))
        strcpy(image_type, "mono");
    else if (strstr(buffer, "packet"))
        strcpy(image_type, "packet");
    else if (strstr(buffer, "init")) {
        /*
         * If due to the user error the driver gets in a bad
         * state where even though it is loaded , the
         * /sys/class/firmware/dell_rbu entries are missing.
         * to cover this situation the user can recreate entries
         * by writing init to image_type.
         */
        if (!rbu_data.entry_created) {
            spin_unlock(&rbu_data.lock);
            req_firm_rc = request_firmware_nowait(THIS_MODULE,
                FW_ACTION_NOHOTPLUG, "dell_rbu",
                &rbu_device->dev, GFP_KERNEL, &context,
                callbackfn_rbu);
            if (req_firm_rc) {
                printk(KERN_ERR
                    "dell_rbu:%s request_firmware_nowait"
                    " failed %d\n", __func__, rc);
                rc = -EIO;
            } else
                rbu_data.entry_created = 1;

            spin_lock(&rbu_data.lock);
        }
    } else {
        printk(KERN_WARNING "dell_rbu: image_type is invalid\n");
        spin_unlock(&rbu_data.lock);
        return -EINVAL;
    }

    /* we must free all previous allocations */
    packet_empty_list();
    img_update_free();
    spin_unlock(&rbu_data.lock);

    return rc;
}

static ssize_t read_rbu_packet_size(struct file *filp, struct kobject *kobj,
                    struct bin_attribute *bin_attr,
                    char *buffer, loff_t pos, size_t count)
{
    int size = 0;
    if (!pos) {
        spin_lock(&rbu_data.lock);
        size = scnprintf(buffer, count, "%lu\n", rbu_data.packetsize);
        spin_unlock(&rbu_data.lock);
    }
    return size;
}

static ssize_t write_rbu_packet_size(struct file *filp, struct kobject *kobj,
                     struct bin_attribute *bin_attr,
                     char *buffer, loff_t pos, size_t count)
{
    unsigned long temp;
    spin_lock(&rbu_data.lock);
    packet_empty_list();
    sscanf(buffer, "%lu", &temp);
    if (temp < 0xffffffff)
        rbu_data.packetsize = temp;

    spin_unlock(&rbu_data.lock);
    return count;
}

static struct bin_attribute rbu_data_attr = {
    .attr = {.name = "data", .mode = 0444},
    .read = read_rbu_data,
};

static struct bin_attribute rbu_image_type_attr = {
    .attr = {.name = "image_type", .mode = 0644},
    .read = read_rbu_image_type,
    .write = write_rbu_image_type,
};

static struct bin_attribute rbu_packet_size_attr = {
    .attr = {.name = "packet_size", .mode = 0644},
    .read = read_rbu_packet_size,
    .write = write_rbu_packet_size,
};

static int __init dcdrbu_init(void)
{
    int rc;
    spin_lock_init(&rbu_data.lock);

    init_packet_head();
    rbu_device = platform_device_register_simple("dell_rbu", -1, NULL, 0);
    if (IS_ERR(rbu_device)) {
        printk(KERN_ERR
            "dell_rbu:%s:platform_device_register_simple "
            "failed\n", __func__);
        return PTR_ERR(rbu_device);
    }

    rc = sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_data_attr);
    if (rc)
        goto out_devreg;
    rc = sysfs_create_bin_file(&rbu_device->dev.kobj, &rbu_image_type_attr);
    if (rc)
        goto out_data;
    rc = sysfs_create_bin_file(&rbu_device->dev.kobj,
        &rbu_packet_size_attr);
    if (rc)
        goto out_imtype;

    rbu_data.entry_created = 0;
    return 0;

out_imtype:
    sysfs_remove_bin_file(&rbu_device->dev.kobj, &rbu_image_type_attr);
out_data:
    sysfs_remove_bin_file(&rbu_device->dev.kobj, &rbu_data_attr);
out_devreg:
    platform_device_unregister(rbu_device);
    return rc;
}

static __exit void dcdrbu_exit(void)
{
    spin_lock(&rbu_data.lock);
    packet_empty_list();
    img_update_free();
    spin_unlock(&rbu_data.lock);
    platform_device_unregister(rbu_device);
}

module_exit(dcdrbu_exit);
module_init(dcdrbu_init);

/* vim:noet:ts=8:sw=8
*/