source: src/linux/brcm/linux-2.6.23/arch/mips/brcm-boards/bcm947xx/nvram_linux.c @ 12701

/*
 * NVRAM variable manipulation (Linux kernel half)
 *
 * Copyright (C) 2008, Broadcom Corporation
 * All Rights Reserved.
 * 
 * THIS SOFTWARE IS OFFERED "AS IS", AND BROADCOM GRANTS NO WARRANTIES OF ANY
 * KIND, EXPRESS OR IMPLIED, BY STATUTE, COMMUNICATION OR OTHERWISE. BROADCOM
 * SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A SPECIFIC PURPOSE OR NONINFRINGEMENT CONCERNING THIS SOFTWARE.
 *
 * $Id: nvram_linux.c,v 1.8 2008/07/04 01:15:09 Exp $
 */

#include <linux/config.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/bootmem.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/mtd/mtd.h>
#include <linux/devfs_fs_kernel.h>
#include <asm/addrspace.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>

#include <typedefs.h>
#include <bcmendian.h>
#include <bcmnvram.h>
#include <bcmutils.h>
#include <bcmdefs.h>
#include <hndsoc.h>
#include <siutils.h>
#include <hndmips.h>
#include <sflash.h>

/* In BSS to minimize text size and page aligned so it can be mmap()-ed */
static char nvram_buf[NVRAM_SPACE] __attribute__((aligned(PAGE_SIZE)));

#ifdef MODULE

#define early_nvram_get(name) nvram_get(name)

#else /* !MODULE */

/* Global SB handle */
extern void *bcm947xx_sih;
extern spinlock_t bcm947xx_sih_lock;

static int cfe_env;
extern char *cfe_env_get(char *nv_buf, const char *name);

/* Convenience */
#define sih bcm947xx_sih
#define sih_lock bcm947xx_sih_lock
#define KB * 1024
#define MB * 1024 * 1024

/* Probe for NVRAM header */
static int
early_nvram_init(void)
{
        struct nvram_header *header;
        chipcregs_t *cc;
        struct sflash *info = NULL;
        int i;
        uint32 base, off, lim;
        u32 *src, *dst;

        if ((cc = si_setcore(sih, CC_CORE_ID, 0)) != NULL) {
                base = KSEG1ADDR(SI_FLASH2);
                switch (readl(&cc->capabilities) & CC_CAP_FLASH_MASK) {
                case PFLASH:
                        lim = SI_FLASH2_SZ;
                        break;

                case SFLASH_ST:
                case SFLASH_AT:
                        if ((info = sflash_init(sih, cc)) == NULL)
                                return -1;
                        lim = info->size;
                        break;

                case FLASH_NONE:
                default:
                        return -1;
                }
        } else {
                /* extif assumed, Stop at 4 MB */
                base = KSEG1ADDR(SI_FLASH1);
                lim = SI_FLASH1_SZ;
        }

        src = (u32 *) KSEG1ADDR(base + 8 * 1024 * 1024 - 0x2000);
        dst = (u32 *) nvram_buf;
        if ((lim == 0x02000000) && ((*src & 0xff00ff) == 0x000001)) {
                printk("early_nvram_init: WGT634U NVRAM found.\n");

                for (i = 0; i < 0x1ff0; i++) {
                        if (*src == 0xFFFFFFFF)
                                break;
                        *dst++ = *src++;
                }
                cfe_env = 1;
                return 0;
        }

        off = FLASH_MIN;
        while (off <= lim) {
                /* Windowed flash access */
                header = (struct nvram_header *) KSEG1ADDR(base + off - NVRAM_SPACE);
                if (header->magic == NVRAM_MAGIC)
                        if (nvram_calc_crc(header) == (uint8) header->crc_ver_init) {
                                goto found;
                        }
                off <<= 1;
        }

        /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
        header = (struct nvram_header *) KSEG1ADDR(base + 4 KB);
        if (header->magic == NVRAM_MAGIC)
                if (nvram_calc_crc(header) == (uint8) header->crc_ver_init) {
                        goto found;
                }

        header = (struct nvram_header *) KSEG1ADDR(base + 1 KB);
        if (header->magic == NVRAM_MAGIC)
                if (nvram_calc_crc(header) == (uint8) header->crc_ver_init) {
                        goto found;
                }

        return -1;

found:
        src = (u32 *) header;
        dst = (u32 *) nvram_buf;
        for (i = 0; i < sizeof(struct nvram_header); i += 4)
                *dst++ = *src++;
        for (; i < header->len && i < NVRAM_SPACE; i += 4)
                *dst++ = ltoh32(*src++);

        return 0;
}

/* Early (before mm or mtd) read-only access to NVRAM */
static char *
early_nvram_get(const char *name)
{
        char *var, *value, *end, *eq;

        if (!name)
                return NULL;

        /* Too early? */
        if (sih == NULL)
                return NULL;

        if (!nvram_buf[0])
                if (early_nvram_init() != 0) {
                        printk("early_nvram_get: Failed reading nvram var %s\n", name);
                        return NULL;
                }

        if (cfe_env)
                return cfe_env_get(nvram_buf, name);

        /* Look for name=value and return value */
        var = &nvram_buf[sizeof(struct nvram_header)];
        end = nvram_buf + sizeof(nvram_buf) - 2;
        end[0] = end[1] = '\0';
        for (; *var; var = value + strlen(value) + 1) {
                if (!(eq = strchr(var, '=')))
                        break;
                value = eq + 1;
                if ((eq - var) == strlen(name) && strncmp(var, name, (eq - var)) == 0)
                        return value;
        }

        return NULL;
}

static int
early_nvram_getall(char *buf, int count)
{
        char *var, *end;
        int len = 0;

        /* Too early? */
        if (sih == NULL)
                return -1;

        if (!nvram_buf[0])
                if (early_nvram_init() != 0) {
                        printk("early_nvram_getall: Failed reading nvram var\n");
                        return -1;
                }

        bzero(buf, count);

        /* Write name=value\0 ... \0\0 */
        var = &nvram_buf[sizeof(struct nvram_header)];
        end = nvram_buf + sizeof(nvram_buf) - 2;
        end[0] = end[1] = '\0';
        for (; *var; var += strlen(var) + 1) {
                if ((count - len) <= (strlen(var) + 1))
                        break;
                len += sprintf(buf + len, "%s", var) + 1;
        }

        return 0;
}
#endif /* !MODULE */

extern char * _nvram_get(const char *name);
extern int _nvram_set(const char *name, const char *value);
extern int _nvram_unset(const char *name);
extern int _nvram_getall(char *buf, int count);
extern int _nvram_commit(struct nvram_header *header);
extern int _nvram_init(void *sih);
extern void _nvram_exit(void);

/* Globals */
static spinlock_t nvram_lock = SPIN_LOCK_UNLOCKED;
static struct semaphore nvram_sem;
static unsigned long nvram_offset = 0;
static int nvram_major = -1;
static struct class *nvram_class = NULL;
static struct mtd_info *nvram_mtd = NULL;

int
_nvram_read(char *buf)
{
        struct nvram_header *header = (struct nvram_header *) buf;
        size_t len;

        if (!nvram_mtd ||
            nvram_mtd->read(nvram_mtd, nvram_mtd->size - NVRAM_SPACE, NVRAM_SPACE, &len, buf) ||
            len != NVRAM_SPACE ||
            header->magic != NVRAM_MAGIC) {
                /* Maybe we can recover some data from early initialization */
                memcpy(buf, nvram_buf, NVRAM_SPACE);
        }

        return 0;
}

struct nvram_tuple *
_nvram_realloc(struct nvram_tuple *t, const char *name, const char *value)
{
        if ((nvram_offset + strlen(value) + 1) > NVRAM_SPACE)
                return NULL;

        if (!t) {
                if (!(t = kmalloc(sizeof(struct nvram_tuple) + strlen(name) + 1, GFP_ATOMIC)))
                        return NULL;

                /* Copy name */
                t->name = (char *) &t[1];
                strcpy(t->name, name);

                t->value = NULL;
        }

        /* Copy value */
        if (!t->value || strcmp(t->value, value)) {
                t->value = &nvram_buf[nvram_offset];
                strcpy(t->value, value);
                nvram_offset += strlen(value) + 1;
        }

        return t;
}

void
_nvram_free(struct nvram_tuple *t)
{
        if (!t)
                nvram_offset = 0;
        else
                kfree(t);
}

int
nvram_init(void *sih)
{
        return 0;
}

int
nvram_set(const char *name, const char *value)
{
        unsigned long flags;
        int ret;
        struct nvram_header *header;

        spin_lock_irqsave(&nvram_lock, flags);
        if ((ret = _nvram_set(name, value))) {
                /* Consolidate space and try again */
                if ((header = kmalloc(NVRAM_SPACE, GFP_ATOMIC))) {
                        if (_nvram_commit(header) == 0)
                                ret = _nvram_set(name, value);
                        kfree(header);
                }
        }
        spin_unlock_irqrestore(&nvram_lock, flags);

        return ret;
}

char *
real_nvram_get(const char *name)
{
        unsigned long flags;
        char *value;

        spin_lock_irqsave(&nvram_lock, flags);
        value = _nvram_get(name);
        spin_unlock_irqrestore(&nvram_lock, flags);

        return value;
}

char *
nvram_get(const char *name)
{
        if (nvram_major >= 0)
                return real_nvram_get(name);
        else
                return early_nvram_get(name);
}

int
nvram_unset(const char *name)
{
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&nvram_lock, flags);
        ret = _nvram_unset(name);
        spin_unlock_irqrestore(&nvram_lock, flags);

        return ret;
}

static void
erase_callback(struct erase_info *done)
{
        wait_queue_head_t *wait_q = (wait_queue_head_t *) done->priv;
        wake_up(wait_q);
}

int
nvram_commit(void)
{
        char *buf;
        size_t erasesize, len, magic_len;
        unsigned int i;
        int ret;
        struct nvram_header *header;
        unsigned long flags;
        u_int32_t offset;
        DECLARE_WAITQUEUE(wait, current);
        wait_queue_head_t wait_q;
        struct erase_info erase;
        u_int32_t magic_offset = 0; /* Offset for writing MAGIC # */

        if (!nvram_mtd) {
                printk("nvram_commit: NVRAM not found\n");
                return -ENODEV;
        }

        if (in_interrupt()) {
                printk("nvram_commit: not committing in interrupt\n");
                return -EINVAL;
        }

        /* Backup sector blocks to be erased */
        erasesize = ROUNDUP(NVRAM_SPACE, nvram_mtd->erasesize);
        if (!(buf = kmalloc(erasesize, GFP_KERNEL))) {
                printk("nvram_commit: out of memory\n");
                return -ENOMEM;
        }

        down(&nvram_sem);

        if ((i = erasesize - NVRAM_SPACE) > 0) {
                offset = nvram_mtd->size - erasesize;
                len = 0;
                ret = nvram_mtd->read(nvram_mtd, offset, i, &len, buf);
                if (ret || len != i) {
                        printk("nvram_commit: read error ret = %d, len = %d/%d\n", ret, len, i);
                        ret = -EIO;
                        goto done;
                }
                header = (struct nvram_header *)(buf + i);
                magic_offset = i + ((void *)&header->magic - (void *)header);
        } else {
                offset = nvram_mtd->size - NVRAM_SPACE;
                magic_offset = ((void *)&header->magic - (void *)header);
                header = (struct nvram_header *)buf;
        }

        /* clear the existing magic # to mark the NVRAM as unusable 
         * we can pull MAGIC bits low without erase
         */
        header->magic = NVRAM_CLEAR_MAGIC; /* All zeros magic */
        /* Unlock sector blocks */
        if (nvram_mtd->unlock)
                nvram_mtd->unlock(nvram_mtd, offset, nvram_mtd->erasesize);
        ret = nvram_mtd->write(nvram_mtd, offset + magic_offset, sizeof(header->magic),
                &magic_len, (char *)&header->magic);
        if (ret || magic_len != sizeof(header->magic)) {
                printk("nvram_commit: clear MAGIC error\n");
                ret = -EIO;
                goto done;
        }

        header->magic = NVRAM_MAGIC;
        /* reset MAGIC before we regenerate the NVRAM,
         * otherwise we'll have an incorrect CRC
         */
        /* Regenerate NVRAM */
        spin_lock_irqsave(&nvram_lock, flags);
        ret = _nvram_commit(header);
        spin_unlock_irqrestore(&nvram_lock, flags);
        if (ret)
                goto done;

        /* Erase sector blocks */
        init_waitqueue_head(&wait_q);
        for (; offset < nvram_mtd->size - NVRAM_SPACE + header->len;
                offset += nvram_mtd->erasesize) {

                erase.mtd = nvram_mtd;
                erase.addr = offset;
                erase.len = nvram_mtd->erasesize;
                erase.callback = erase_callback;
                erase.priv = (u_long) &wait_q;

                set_current_state(TASK_INTERRUPTIBLE);
                add_wait_queue(&wait_q, &wait);

                /* Unlock sector blocks */
                if (nvram_mtd->unlock)
                        nvram_mtd->unlock(nvram_mtd, offset, nvram_mtd->erasesize);

                if ((ret = nvram_mtd->erase(nvram_mtd, &erase))) {
                        set_current_state(TASK_RUNNING);
                        remove_wait_queue(&wait_q, &wait);
                        printk("nvram_commit: erase error\n");
                        goto done;
                }

                /* Wait for erase to finish */
                schedule();
                remove_wait_queue(&wait_q, &wait);
        }

        /* Write partition up to end of data area */
        header->magic = NVRAM_INVALID_MAGIC; /* All ones magic */
        offset = nvram_mtd->size - erasesize;
        i = erasesize - NVRAM_SPACE + header->len;
        ret = nvram_mtd->write(nvram_mtd, offset, i, &len, buf);
        if (ret || len != i) {
                printk("nvram_commit: write error\n");
                ret = -EIO;
                goto done;
        }

        /* Now mark the NVRAM in flash as "valid" by setting the correct
         * MAGIC #
         */
        header->magic = NVRAM_MAGIC;
        ret = nvram_mtd->write(nvram_mtd, offset + magic_offset, sizeof(header->magic),
                &magic_len, (char *)&header->magic);
        if (ret || magic_len != sizeof(header->magic)) {
                printk("nvram_commit: write MAGIC error\n");
                ret = -EIO;
                goto done;
        }

        offset = nvram_mtd->size - erasesize;
        ret = nvram_mtd->read(nvram_mtd, offset, 4, &len, buf);

done:
        up(&nvram_sem);
        kfree(buf);
        return ret;
}

int
nvram_getall(char *buf, int count)
{
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&nvram_lock, flags);
        if (nvram_major >= 0)
                ret = _nvram_getall(buf, count);
        else
                ret = early_nvram_getall(buf, count);
        spin_unlock_irqrestore(&nvram_lock, flags);

        return ret;
}

EXPORT_SYMBOL(nvram_init);
EXPORT_SYMBOL(nvram_get);
EXPORT_SYMBOL(nvram_getall);
EXPORT_SYMBOL(nvram_set);
EXPORT_SYMBOL(nvram_unset);
EXPORT_SYMBOL(nvram_commit);

/* User mode interface below */

static ssize_t
dev_nvram_read(struct file *file, char *buf, size_t count, loff_t *ppos)
{
        char tmp[100], *name = tmp, *value;
        ssize_t ret;
        unsigned long off;

        if (count > sizeof(tmp)) {
                if (!(name = kmalloc(count, GFP_KERNEL)))
                        return -ENOMEM;
        }

        if (copy_from_user(name, buf, count)) {
                ret = -EFAULT;
                goto done;
        }

        if (*name == '\0') {
                /* Get all variables */
                ret = nvram_getall(name, count);
                if (ret == 0) {
                        if (copy_to_user(buf, name, count)) {
                                ret = -EFAULT;
                                goto done;
                        }
                        ret = count;
                }
        } else {
                if (!(value = nvram_get(name))) {
                        ret = 0;
                        goto done;
                }

                /* Provide the offset into mmap() space */
                off = (unsigned long) value - (unsigned long) nvram_buf;

                if (put_user(off, (unsigned long *) buf)) {
                        ret = -EFAULT;
                        goto done;
                }

                ret = sizeof(unsigned long);
        }

        flush_cache_all();

done:
        if (name != tmp)
                kfree(name);

        return ret;
}

static ssize_t
dev_nvram_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
        char tmp[100], *name = tmp, *value;
        ssize_t ret;

        if (count > sizeof(tmp)) {
                if (!(name = kmalloc(count, GFP_KERNEL)))
                        return -ENOMEM;
        }

        if (copy_from_user(name, buf, count)) {
                ret = -EFAULT;
                goto done;
        }

        value = name;
        name = strsep(&value, "=");
        if (value)
                ret = nvram_set(name, value) ? : count;
        else
                ret = nvram_unset(name) ? : count;

done:
        if (name != tmp)
                kfree(name);

        return ret;
}

static int
dev_nvram_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
        if (cmd != NVRAM_MAGIC)
                return -EINVAL;

        return nvram_commit();
}

static int
dev_nvram_mmap(struct file *file, struct vm_area_struct *vma)
{
        unsigned long offset = __pa(nvram_buf) >> PAGE_SHIFT;

        if (remap_pfn_range(vma, vma->vm_start, offset,
                            vma->vm_end - vma->vm_start,
                            vma->vm_page_prot))
                return -EAGAIN;

        return 0;
}

static int
dev_nvram_open(struct inode *inode, struct file * file)
{
        return 0;
}

static int
dev_nvram_release(struct inode *inode, struct file * file)
{
        return 0;
}

static struct file_operations dev_nvram_fops = {
        owner:          THIS_MODULE,
        open:           dev_nvram_open,
        release:        dev_nvram_release,
        read:           dev_nvram_read,
        write:          dev_nvram_write,
        ioctl:          dev_nvram_ioctl,
        mmap:           dev_nvram_mmap
};

static void
dev_nvram_exit(void)
{
        int order = 0;
        struct page *page, *end;

        if (nvram_class) {
                class_device_destroy(nvram_class, MKDEV(nvram_major, 0));
                class_destroy(nvram_class);
        }

        if (nvram_major >= 0)
                unregister_chrdev(nvram_major, "nvram");

        if (nvram_mtd)
                put_mtd_device(nvram_mtd);

        while ((PAGE_SIZE << order) < NVRAM_SPACE)
                order++;
        end = virt_to_page(nvram_buf + (PAGE_SIZE << order) - 1);
        for (page = virt_to_page(nvram_buf); page <= end; page++)
                ClearPageReserved(page);

        _nvram_exit();
}

static int
dev_nvram_init(void)
{
        int order = 0, ret = 0;
        struct page *page, *end;
        unsigned int i;
        osl_t *osh;

        /* Allocate and reserve memory to mmap() */
        while ((PAGE_SIZE << order) < NVRAM_SPACE)
                order++;
        end = virt_to_page(nvram_buf + (PAGE_SIZE << order) - 1);
        for (page = virt_to_page(nvram_buf); page <= end; page++) {
                SetPageReserved(page);
        }

#if defined(CONFIG_MTD) || defined(CONFIG_MTD_MODULE)
        /* Find associated MTD device */
        for (i = 0; i < MAX_MTD_DEVICES; i++) {
                nvram_mtd = get_mtd_device(NULL, i);
                if (!IS_ERR(nvram_mtd)) {
                        if (!strcmp(nvram_mtd->name, "nvram") &&
                            nvram_mtd->size >= NVRAM_SPACE) {
                                break;
                        }
                        put_mtd_device(nvram_mtd);
                }
        }
        if (i >= MAX_MTD_DEVICES)
                nvram_mtd = NULL;
        if (nvram_mtd==NULL)
            printk("no nvram found\n");
#endif

        /* Initialize hash table lock */
        spin_lock_init(&nvram_lock);

        /* Initialize commit semaphore */
        init_MUTEX(&nvram_sem);

        /* Register char device */
        if ((nvram_major = register_chrdev(229, "nvram", &dev_nvram_fops)) < 0) {
                ret = nvram_major;
                goto err;
        }

        if (si_osh(sih) == NULL) {
                osh = osl_attach(NULL, SI_BUS, FALSE);
                if (osh == NULL) {
                        printk("Error allocating osh\n");
                        unregister_chrdev(nvram_major, "nvram");
                        goto err;
                }
                si_setosh(sih, osh);
        }

        /* Initialize hash table */
        _nvram_init(sih);

        /* Create /dev/nvram handle */
        nvram_class = class_create(THIS_MODULE, "nvram");
        if (IS_ERR(nvram_class)) {
                printk("Error creating nvram class\n");
                goto err;
        }
//      devfs_mk_cdev(MKDEV(nvram_major, 0), S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP, "nvram");

        /* Add the device nvram0 */
        class_device_create(nvram_class, NULL, MKDEV(229, 0), NULL, "nvram");

        /* Set the SDRAM NCDL value into NVRAM if not already done */
        if (getintvar(NULL, "sdram_ncdl") == 0) {
                unsigned int ncdl;
                char buf[] = "0x00000000";

                if ((ncdl = si_memc_get_ncdl(sih))) {
                        sprintf(buf, "0x%08x", ncdl);
                        nvram_set("sdram_ncdl", buf);
                        nvram_commit();
                }
        }

        return 0;

err:
        printk("Error initialising nvram %d\n",ret);
        dev_nvram_exit();
        return ret;
}

late_initcall(dev_nvram_init);
module_exit(dev_nvram_exit);