/*
 *  c 2001 PPC 64 Team, IBM Corp
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 *
 * /proc/powerpc/rtas/firmware_flash interface
 *
 * This file implements a firmware_flash interface to pump a firmware
 * image into the kernel.  At reboot time rtas_restart() will see the
 * firmware image and flash it as it reboots (see rtas.c).
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/reboot.h>
#include <asm/delay.h>
#include <asm/uaccess.h>
#include <asm/rtas.h>
#include <asm/abs_addr.h>

#define MODULE_VERS "1.0"
#define MODULE_NAME "rtas_flash"

#define FIRMWARE_FLASH_NAME "firmware_flash"   
#define FIRMWARE_UPDATE_NAME "firmware_update"
#define MANAGE_FLASH_NAME "manage_flash"
#define VALIDATE_FLASH_NAME "validate_flash"

/* General RTAS Status Codes */
#define RTAS_RC_SUCCESS  0
#define RTAS_RC_HW_ERR  -1
#define RTAS_RC_BUSY    -2

/* Flash image status values */
#define FLASH_AUTH           -9002 /* RTAS Not Service Authority Partition */
#define FLASH_NO_OP          -1099 /* No operation initiated by user */ 
#define FLASH_IMG_SHORT      -1005 /* Flash image shorter than expected */
#define FLASH_IMG_BAD_LEN    -1004 /* Bad length value in flash list block */
#define FLASH_IMG_NULL_DATA  -1003 /* Bad data value in flash list block */
#define FLASH_IMG_READY      0     /* Firmware img ready for flash on reboot */

/* Manage image status values */
#define MANAGE_AUTH          -9002 /* RTAS Not Service Authority Partition */
#define MANAGE_ACTIVE_ERR    -9001 /* RTAS Cannot Overwrite Active Img */
#define MANAGE_NO_OP         -1099 /* No operation initiated by user */
#define MANAGE_PARAM_ERR     -3    /* RTAS Parameter Error */
#define MANAGE_HW_ERR        -1    /* RTAS Hardware Error */

/* Validate image status values */
#define VALIDATE_AUTH          -9002 /* RTAS Not Service Authority Partition */
#define VALIDATE_NO_OP         -1099 /* No operation initiated by the user */
#define VALIDATE_INCOMPLETE    -1002 /* User copied < VALIDATE_BUF_SIZE */
#define VALIDATE_READY         -1001 /* Firmware image ready for validation */
#define VALIDATE_PARAM_ERR     -3    /* RTAS Parameter Error */
#define VALIDATE_HW_ERR        -1    /* RTAS Hardware Error */
#define VALIDATE_TMP_UPDATE    0     /* Validate Return Status */
#define VALIDATE_FLASH_AUTH    1     /* Validate Return Status */
#define VALIDATE_INVALID_IMG   2     /* Validate Return Status */
#define VALIDATE_CUR_UNKNOWN   3     /* Validate Return Status */
#define VALIDATE_TMP_COMMIT_DL 4     /* Validate Return Status */
#define VALIDATE_TMP_COMMIT    5     /* Validate Return Status */
#define VALIDATE_TMP_UPDATE_DL 6     /* Validate Return Status */

/* ibm,manage-flash-image operation tokens */
#define RTAS_REJECT_TMP_IMG   0
#define RTAS_COMMIT_TMP_IMG   1

/* Array sizes */
#define VALIDATE_BUF_SIZE 4096    
#define RTAS_MSG_MAXLEN   64

/* Quirk - RTAS requires 4k list length and block size */
#define RTAS_BLKLIST_LENGTH 4096
#define RTAS_BLK_SIZE 4096

struct flash_block {
        char *data;
        unsigned long length;
};

/* This struct is very similar but not identical to
 * that needed by the rtas flash update.
 * All we need to do for rtas is rewrite num_blocks
 * into a version/length and translate the pointers
 * to absolute.
 */
#define FLASH_BLOCKS_PER_NODE ((RTAS_BLKLIST_LENGTH - 16) / sizeof(struct flash_block))
struct flash_block_list {
        unsigned long num_blocks;
        struct flash_block_list *next;
        struct flash_block blocks[FLASH_BLOCKS_PER_NODE];
};

static struct flash_block_list *rtas_firmware_flash_list;

/* Use slab cache to guarantee 4k alignment */
static struct kmem_cache *flash_block_cache = NULL;

#define FLASH_BLOCK_LIST_VERSION (1UL)

/* Local copy of the flash block list.
 * We only allow one open of the flash proc file and create this
 * list as we go.  The rtas_firmware_flash_list varable will be
 * set once the data is fully read.
 *
 * For convenience as we build the list we use virtual addrs,
 * we do not fill in the version number, and the length field
 * is treated as the number of entries currently in the block
 * (i.e. not a byte count).  This is all fixed when calling 
 * the flash routine.
 */

/* Status int must be first member of struct */
struct rtas_update_flash_t
{
        int status;                     /* Flash update status */
        struct flash_block_list *flist; /* Local copy of flash block list */
};

/* Status int must be first member of struct */
struct rtas_manage_flash_t
{
        int status;                     /* Returned status */
        unsigned int op;                /* Reject or commit image */
};

/* Status int must be first member of struct */
struct rtas_validate_flash_t
{
        int status;                     /* Returned status */   
        char buf[VALIDATE_BUF_SIZE];    /* Candidate image buffer */
        unsigned int buf_size;          /* Size of image buf */
        unsigned int update_results;    /* Update results token */
};

static DEFINE_SPINLOCK(flash_file_open_lock);
static struct proc_dir_entry *firmware_flash_pde;
static struct proc_dir_entry *firmware_update_pde;
static struct proc_dir_entry *validate_pde;
static struct proc_dir_entry *manage_pde;

/* Do simple sanity checks on the flash image. */
static int flash_list_valid(struct flash_block_list *flist)
{
        struct flash_block_list *f;
        int i;
        unsigned long block_size, image_size;

        /* Paranoid self test here.  We also collect the image size. */
        image_size = 0;
        for (f = flist; f; f = f->next) {
                for (i = 0; i < f->num_blocks; i++) {
                        if (f->blocks[i].data == NULL) {
                                return FLASH_IMG_NULL_DATA;
                        }
                        block_size = f->blocks[i].length;
                        if (block_size <= 0 || block_size > RTAS_BLK_SIZE) {
                                return FLASH_IMG_BAD_LEN;
                        }
                        image_size += block_size;
                }
        }

        if (image_size < (256 << 10)) {
                if (image_size < 2) 
                        return FLASH_NO_OP;
        }

        printk(KERN_INFO "FLASH: flash image with %ld bytes stored for hardware flash on reboot\n", image_size);

        return FLASH_IMG_READY;
}

static void free_flash_list(struct flash_block_list *f)
{
        struct flash_block_list *next;
        int i;

        while (f) {
                for (i = 0; i < f->num_blocks; i++)
                        kmem_cache_free(flash_block_cache, f->blocks[i].data);
                next = f->next;
                kmem_cache_free(flash_block_cache, f);
                f = next;
        }
}

static int rtas_flash_release(struct inode *inode, struct file *file)
{
        struct proc_dir_entry *dp = PDE(file->f_path.dentry->d_inode);
        struct rtas_update_flash_t *uf;
        
        uf = (struct rtas_update_flash_t *) dp->data;
        if (uf->flist) {    
                /* File was opened in write mode for a new flash attempt */
                /* Clear saved list */
                if (rtas_firmware_flash_list) {
                        free_flash_list(rtas_firmware_flash_list);
                        rtas_firmware_flash_list = NULL;
                }

                if (uf->status != FLASH_AUTH)  
                        uf->status = flash_list_valid(uf->flist);

                if (uf->status == FLASH_IMG_READY) 
                        rtas_firmware_flash_list = uf->flist;
                else
                        free_flash_list(uf->flist);

                uf->flist = NULL;
        }

        atomic_dec(&dp->count);
        return 0;
}

static void get_flash_status_msg(int status, char *buf)
{
        char *msg;

        switch (status) {
        case FLASH_AUTH:
                msg = "error: this partition does not have service authority\n";
                break;
        case FLASH_NO_OP:
                msg = "info: no firmware image for flash\n";
                break;
        case FLASH_IMG_SHORT:
                msg = "error: flash image short\n";
                break;
        case FLASH_IMG_BAD_LEN:
                msg = "error: internal error bad length\n";
                break;
        case FLASH_IMG_NULL_DATA:
                msg = "error: internal error null data\n";
                break;
        case FLASH_IMG_READY:
                msg = "ready: firmware image ready for flash on reboot\n";
                break;
        default:
                sprintf(buf, "error: unexpected status value %d\n", status);
                return;
        }

        strcpy(buf, msg);       
}

/* Reading the proc file will show status (not the firmware contents) */
static ssize_t rtas_flash_read(struct file *file, char __user *buf,
                               size_t count, loff_t *ppos)
{
        struct proc_dir_entry *dp = PDE(file->f_path.dentry->d_inode);
        struct rtas_update_flash_t *uf;
        char msg[RTAS_MSG_MAXLEN];

        uf = dp->data;

        if (!strcmp(dp->name, FIRMWARE_FLASH_NAME)) {
                get_flash_status_msg(uf->status, msg);
        } else {           /* FIRMWARE_UPDATE_NAME */
                sprintf(msg, "%d\n", uf->status);
        }

        return simple_read_from_buffer(buf, count, ppos, msg, strlen(msg));
}

/* constructor for flash_block_cache */
void rtas_block_ctor(void *ptr)
{
        memset(ptr, 0, RTAS_BLK_SIZE);
}

/* We could be much more efficient here.  But to keep this function
 * simple we allocate a page to the block list no matter how small the
 * count is.  If the system is low on memory it will be just as well
 * that we fail....
 */
static ssize_t rtas_flash_write(struct file *file, const char __user *buffer,
                                size_t count, loff_t *off)
{
        struct proc_dir_entry *dp = PDE(file->f_path.dentry->d_inode);
        struct rtas_update_flash_t *uf;
        char *p;
        int next_free;
        struct flash_block_list *fl;

        uf = (struct rtas_update_flash_t *) dp->data;

        if (uf->status == FLASH_AUTH || count == 0)
                return count;   /* discard data */

        /* In the case that the image is not ready for flashing, the memory
         * allocated for the block list will be freed upon the release of the 
         * proc file
         */
        if (uf->flist == NULL) {
                uf->flist = kmem_cache_alloc(flash_block_cache, GFP_KERNEL);
                if (!uf->flist)
                        return -ENOMEM;
        }

        fl = uf->flist;
        while (fl->next)
                fl = fl->next; /* seek to last block_list for append */
        next_free = fl->num_blocks;
        if (next_free == FLASH_BLOCKS_PER_NODE) {
                /* Need to allocate another block_list */
                fl->next = kmem_cache_alloc(flash_block_cache, GFP_KERNEL);
                if (!fl->next)
                        return -ENOMEM;
                fl = fl->next;
                next_free = 0;
        }

        if (count > RTAS_BLK_SIZE)
                count = RTAS_BLK_SIZE;
        p = kmem_cache_alloc(flash_block_cache, GFP_KERNEL);
        if (!p)
                return -ENOMEM;
        
        if(copy_from_user(p, buffer, count)) {
                kmem_cache_free(flash_block_cache, p);
                return -EFAULT;
        }
        fl->blocks[next_free].data = p;
        fl->blocks[next_free].length = count;
        fl->num_blocks++;

        return count;
}

static int rtas_excl_open(struct inode *inode, struct file *file)
{
        struct proc_dir_entry *dp = PDE(inode);

        /* Enforce exclusive open with use count of PDE */
        spin_lock(&flash_file_open_lock);
        if (atomic_read(&dp->count) > 2) {
                spin_unlock(&flash_file_open_lock);
                return -EBUSY;
        }

        atomic_inc(&dp->count);
        spin_unlock(&flash_file_open_lock);
        
        return 0;
}

static int rtas_excl_release(struct inode *inode, struct file *file)
{
        struct proc_dir_entry *dp = PDE(inode);

        atomic_dec(&dp->count);

        return 0;
}

static void manage_flash(struct rtas_manage_flash_t *args_buf)
{
        s32 rc;

        do {
                rc = rtas_call(rtas_token("ibm,manage-flash-image"), 1, 
                               1, NULL, args_buf->op);
        } while (rtas_busy_delay(rc));

        args_buf->status = rc;
}

static ssize_t manage_flash_read(struct file *file, char __user *buf,
                               size_t count, loff_t *ppos)
{
        struct proc_dir_entry *dp = PDE(file->f_path.dentry->d_inode);
        struct rtas_manage_flash_t *args_buf;
        char msg[RTAS_MSG_MAXLEN];
        int msglen;

        args_buf = dp->data;
        if (args_buf == NULL)
                return 0;

        msglen = sprintf(msg, "%d\n", args_buf->status);

        return simple_read_from_buffer(buf, count, ppos, msg, msglen);
}

static ssize_t manage_flash_write(struct file *file, const char __user *buf,
                                size_t count, loff_t *off)
{
        struct proc_dir_entry *dp = PDE(file->f_path.dentry->d_inode);
        struct rtas_manage_flash_t *args_buf;
        const char reject_str[] = "0";
        const char commit_str[] = "1";
        char stkbuf[10];
        int op;

        args_buf = (struct rtas_manage_flash_t *) dp->data;
        if ((args_buf->status == MANAGE_AUTH) || (count == 0))
                return count;
                
        op = -1;
        if (buf) {
                if (count > 9) count = 9;
                if (copy_from_user (stkbuf, buf, count)) {
                        return -EFAULT;
                }
                if (strncmp(stkbuf, reject_str, strlen(reject_str)) == 0) 
                        op = RTAS_REJECT_TMP_IMG;
                else if (strncmp(stkbuf, commit_str, strlen(commit_str)) == 0) 
                        op = RTAS_COMMIT_TMP_IMG;
        }
        
        if (op == -1)   /* buf is empty, or contains invalid string */
                return -EINVAL;

        args_buf->op = op;
        manage_flash(args_buf);

        return count;
}

static void validate_flash(struct rtas_validate_flash_t *args_buf)
{
        int token = rtas_token("ibm,validate-flash-image");
        int update_results;
        s32 rc; 

        rc = 0;
        do {
                spin_lock(&rtas_data_buf_lock);
                memcpy(rtas_data_buf, args_buf->buf, VALIDATE_BUF_SIZE);
                rc = rtas_call(token, 2, 2, &update_results, 
                               (u32) __pa(rtas_data_buf), args_buf->buf_size);
                memcpy(args_buf->buf, rtas_data_buf, VALIDATE_BUF_SIZE);
                spin_unlock(&rtas_data_buf_lock);
        } while (rtas_busy_delay(rc));

        args_buf->status = rc;
        args_buf->update_results = update_results;
}

static int get_validate_flash_msg(struct rtas_validate_flash_t *args_buf, 
                                   char *msg)
{
        int n;

        if (args_buf->status >= VALIDATE_TMP_UPDATE) { 
                n = sprintf(msg, "%d\n", args_buf->update_results);
                if ((args_buf->update_results >= VALIDATE_CUR_UNKNOWN) ||
                    (args_buf->update_results == VALIDATE_TMP_UPDATE))
                        n += sprintf(msg + n, "%s\n", args_buf->buf);
        } else {
                n = sprintf(msg, "%d\n", args_buf->status);
        }
        return n;
}

static ssize_t validate_flash_read(struct file *file, char __user *buf,
                               size_t count, loff_t *ppos)
{
        struct proc_dir_entry *dp = PDE(file->f_path.dentry->d_inode);
        struct rtas_validate_flash_t *args_buf;
        char msg[RTAS_MSG_MAXLEN];
        int msglen;

        args_buf = dp->data;

        msglen = get_validate_flash_msg(args_buf, msg);

        return simple_read_from_buffer(buf, count, ppos, msg, msglen);
}

static ssize_t validate_flash_write(struct file *file, const char __user *buf,
                                    size_t count, loff_t *off)
{
        struct proc_dir_entry *dp = PDE(file->f_path.dentry->d_inode);
        struct rtas_validate_flash_t *args_buf;
        int rc;

        args_buf = (struct rtas_validate_flash_t *) dp->data;

        if (dp->data == NULL) {
                dp->data = kmalloc(sizeof(struct rtas_validate_flash_t), 
                                GFP_KERNEL);
                if (dp->data == NULL) 
                        return -ENOMEM;
        }

        /* We are only interested in the first 4K of the
         * candidate image */
        if ((*off >= VALIDATE_BUF_SIZE) || 
                (args_buf->status == VALIDATE_AUTH)) {
                *off += count;
                return count;
        }

        if (*off + count >= VALIDATE_BUF_SIZE)  {
                count = VALIDATE_BUF_SIZE - *off;
                args_buf->status = VALIDATE_READY;      
        } else {
                args_buf->status = VALIDATE_INCOMPLETE;
        }

        if (!access_ok(VERIFY_READ, buf, count)) {
                rc = -EFAULT;
                goto done;
        }
        if (copy_from_user(args_buf->buf + *off, buf, count)) {
                rc = -EFAULT;
                goto done;
        }

        *off += count;
        rc = count;
done:
        if (rc < 0) {
                kfree(dp->data);
                dp->data = NULL;
        }
        return rc;
}

static int validate_flash_release(struct inode *inode, struct file *file)
{
        struct proc_dir_entry *dp = PDE(file->f_path.dentry->d_inode);
        struct rtas_validate_flash_t *args_buf;

        args_buf = (struct rtas_validate_flash_t *) dp->data;

        if (args_buf->status == VALIDATE_READY) {
                args_buf->buf_size = VALIDATE_BUF_SIZE;
                validate_flash(args_buf);
        }

        /* The matching atomic_inc was in rtas_excl_open() */
        atomic_dec(&dp->count);

        return 0;
}

static void rtas_flash_firmware(int reboot_type)
{
        unsigned long image_size;
        struct flash_block_list *f, *next, *flist;
        unsigned long rtas_block_list;
        int i, status, update_token;

        if (rtas_firmware_flash_list == NULL)
                return;         /* nothing to do */

        if (reboot_type != SYS_RESTART) {
                printk(KERN_ALERT "FLASH: firmware flash requires a reboot\n");
                printk(KERN_ALERT "FLASH: the firmware image will NOT be flashed\n");
                return;
        }

        update_token = rtas_token("ibm,update-flash-64-and-reboot");
        if (update_token == RTAS_UNKNOWN_SERVICE) {
                printk(KERN_ALERT "FLASH: ibm,update-flash-64-and-reboot "
                       "is not available -- not a service partition?\n");
                printk(KERN_ALERT "FLASH: firmware will not be flashed\n");
                return;
        }

        /*
         * Just before starting the firmware flash, cancel the event scan work
         * to avoid any soft lockup issues.
         */
        rtas_cancel_event_scan();

        /*
         * NOTE: the "first" block must be under 4GB, so we create
         * an entry with no data blocks in the reserved buffer in
         * the kernel data segment.
         */
        spin_lock(&rtas_data_buf_lock);
        flist = (struct flash_block_list *)&rtas_data_buf[0];
        flist->num_blocks = 0;
        flist->next = rtas_firmware_flash_list;
        rtas_block_list = virt_to_abs(flist);
        if (rtas_block_list >= 4UL*1024*1024*1024) {
                printk(KERN_ALERT "FLASH: kernel bug...flash list header addr above 4GB\n");
                spin_unlock(&rtas_data_buf_lock);
                return;
        }

        printk(KERN_ALERT "FLASH: preparing saved firmware image for flash\n");
        /* Update the block_list in place. */
        rtas_firmware_flash_list = NULL; /* too hard to backout on error */
        image_size = 0;
        for (f = flist; f; f = next) {
                /* Translate data addrs to absolute */
                for (i = 0; i < f->num_blocks; i++) {
                        f->blocks[i].data = (char *)virt_to_abs(f->blocks[i].data);
                        image_size += f->blocks[i].length;
                }
                next = f->next;
                /* Don't translate NULL pointer for last entry */
                if (f->next)
                        f->next = (struct flash_block_list *)virt_to_abs(f->next);
                else
                        f->next = NULL;
                /* make num_blocks into the version/length field */
                f->num_blocks = (FLASH_BLOCK_LIST_VERSION << 56) | ((f->num_blocks+1)*16);
        }

        printk(KERN_ALERT "FLASH: flash image is %ld bytes\n", image_size);
        printk(KERN_ALERT "FLASH: performing flash and reboot\n");
        rtas_progress("Flashing        \n", 0x0);
        rtas_progress("Please Wait...  ", 0x0);
        printk(KERN_ALERT "FLASH: this will take several minutes.  Do not power off!\n");
        status = rtas_call(update_token, 1, 1, NULL, rtas_block_list);
        switch (status) {       /* should only get "bad" status */
            case 0:
                printk(KERN_ALERT "FLASH: success\n");
                break;
            case -1:
                printk(KERN_ALERT "FLASH: hardware error.  Firmware may not be not flashed\n");
                break;
            case -3:
                printk(KERN_ALERT "FLASH: image is corrupt or not correct for this platform.  Firmware not flashed\n");
                break;
            case -4:
                printk(KERN_ALERT "FLASH: flash failed when partially complete.  System may not reboot\n");
                break;
            default:
                printk(KERN_ALERT "FLASH: unknown flash return code %d\n", status);
                break;
        }
        spin_unlock(&rtas_data_buf_lock);
}

static void remove_flash_pde(struct proc_dir_entry *dp)
{
        if (dp) {
                kfree(dp->data);
                remove_proc_entry(dp->name, dp->parent);
        }
}

static int initialize_flash_pde_data(const char *rtas_call_name,
                                     size_t buf_size,
                                     struct proc_dir_entry *dp)
{
        int *status;
        int token;

        dp->data = kzalloc(buf_size, GFP_KERNEL);
        if (dp->data == NULL) {
                remove_flash_pde(dp);
                return -ENOMEM;
        }

        /*
         * This code assumes that the status int is the first member of the
         * struct 
         */
        status = (int *) dp->data;
        token = rtas_token(rtas_call_name);
        if (token == RTAS_UNKNOWN_SERVICE)
                *status = FLASH_AUTH;
        else
                *status = FLASH_NO_OP;

        return 0;
}

static struct proc_dir_entry *create_flash_pde(const char *filename,
                                               const struct file_operations *fops)
{
        return proc_create(filename, S_IRUSR | S_IWUSR, NULL, fops);
}

static const struct file_operations rtas_flash_operations = {
        .owner          = THIS_MODULE,
        .read           = rtas_flash_read,
        .write          = rtas_flash_write,
        .open           = rtas_excl_open,
        .release        = rtas_flash_release,
        .llseek         = default_llseek,
};

static const struct file_operations manage_flash_operations = {
        .owner          = THIS_MODULE,
        .read           = manage_flash_read,
        .write          = manage_flash_write,
        .open           = rtas_excl_open,
        .release        = rtas_excl_release,
        .llseek         = default_llseek,
};

static const struct file_operations validate_flash_operations = {
        .owner          = THIS_MODULE,
        .read           = validate_flash_read,
        .write          = validate_flash_write,
        .open           = rtas_excl_open,
        .release        = validate_flash_release,
        .llseek         = default_llseek,
};

static int __init rtas_flash_init(void)
{
        int rc;

        if (rtas_token("ibm,update-flash-64-and-reboot") ==
                       RTAS_UNKNOWN_SERVICE) {
                printk(KERN_ERR "rtas_flash: no firmware flash support\n");
                return 1;
        }

        firmware_flash_pde = create_flash_pde("powerpc/rtas/"
                                              FIRMWARE_FLASH_NAME,
                                              &rtas_flash_operations);
        if (firmware_flash_pde == NULL) {
                rc = -ENOMEM;
                goto cleanup;
        }

        rc = initialize_flash_pde_data("ibm,update-flash-64-and-reboot",
                                       sizeof(struct rtas_update_flash_t), 
                                       firmware_flash_pde);
        if (rc != 0)
                goto cleanup;

        firmware_update_pde = create_flash_pde("powerpc/rtas/"
                                               FIRMWARE_UPDATE_NAME,
                                               &rtas_flash_operations);
        if (firmware_update_pde == NULL) {
                rc = -ENOMEM;
                goto cleanup;
        }

        rc = initialize_flash_pde_data("ibm,update-flash-64-and-reboot",
                                       sizeof(struct rtas_update_flash_t), 
                                       firmware_update_pde);
        if (rc != 0)
                goto cleanup;

        validate_pde = create_flash_pde("powerpc/rtas/" VALIDATE_FLASH_NAME,
                                        &validate_flash_operations);
        if (validate_pde == NULL) {
                rc = -ENOMEM;
                goto cleanup;
        }

        rc = initialize_flash_pde_data("ibm,validate-flash-image",
                                       sizeof(struct rtas_validate_flash_t), 
                                       validate_pde);
        if (rc != 0)
                goto cleanup;

        manage_pde = create_flash_pde("powerpc/rtas/" MANAGE_FLASH_NAME,
                                      &manage_flash_operations);
        if (manage_pde == NULL) {
                rc = -ENOMEM;
                goto cleanup;
        }

        rc = initialize_flash_pde_data("ibm,manage-flash-image",
                                       sizeof(struct rtas_manage_flash_t),
                                       manage_pde);
        if (rc != 0)
                goto cleanup;

        rtas_flash_term_hook = rtas_flash_firmware;

        flash_block_cache = kmem_cache_create("rtas_flash_cache",
                                RTAS_BLK_SIZE, RTAS_BLK_SIZE, 0,
                                rtas_block_ctor);
        if (!flash_block_cache) {
                printk(KERN_ERR "%s: failed to create block cache\n",
                                __func__);
                rc = -ENOMEM;
                goto cleanup;
        }
        return 0;

cleanup:
        remove_flash_pde(firmware_flash_pde);
        remove_flash_pde(firmware_update_pde);
        remove_flash_pde(validate_pde);
        remove_flash_pde(manage_pde);

        return rc;
}

static void __exit rtas_flash_cleanup(void)
{
        rtas_flash_term_hook = NULL;

        if (flash_block_cache)
                kmem_cache_destroy(flash_block_cache);

        remove_flash_pde(firmware_flash_pde);
        remove_flash_pde(firmware_update_pde);
        remove_flash_pde(validate_pde);
        remove_flash_pde(manage_pde);
}

module_init(rtas_flash_init);
module_exit(rtas_flash_cleanup);
MODULE_LICENSE("GPL");