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linux/drivers/char/nwflash.c

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/*
* Flash memory interface rev.5 driver for the Intel
* Flash chips used on the NetWinder.
*
* 20/08/2000 RMK use __ioremap to map flash into virtual memory
* make a few more places use "volatile"
* 22/05/2001 RMK - Lock read against write
* - merge printk level changes (with mods) from Alan Cox.
* - use *ppos as the file position, not file->f_pos.
* - fix check for out of range pos and r/w size
*
* Please note that we are tampering with the only flash chip in the
* machine, which contains the bootup code. We therefore have the
* power to convert these machines into doorstops...
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/miscdevice.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/jiffies.h>
#include <asm/hardware/dec21285.h>
#include <asm/io.h>
#include <asm/mach-types.h>
#include <linux/uaccess.h>
/*****************************************************************************/
#include <asm/nwflash.h>
#define NWFLASH_VERSION "6.4"
static DEFINE_MUTEX(flash_mutex);
static void kick_open(void);
static int get_flash_id(void);
static int erase_block(int nBlock);
static int write_block(unsigned long p, const char __user *buf, int count);
#define KFLASH_SIZE 1024*1024 //1 Meg
#define KFLASH_SIZE4 4*1024*1024 //4 Meg
#define KFLASH_ID 0x89A6 //Intel flash
#define KFLASH_ID4 0xB0D4 //Intel flash 4Meg
static bool flashdebug; //if set - we will display progress msgs
static int gbWriteEnable;
static int gbWriteBase64Enable;
static volatile unsigned char *FLASH_BASE;
static int gbFlashSize = KFLASH_SIZE;
static DEFINE_MUTEX(nwflash_mutex);
static int get_flash_id(void)
{
volatile unsigned int c1, c2;
/*
* try to get flash chip ID
*/
kick_open();
c2 = inb(0x80);
*(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x90;
udelay(15);
c1 = *(volatile unsigned char *) FLASH_BASE;
c2 = inb(0x80);
/*
* on 4 Meg flash the second byte is actually at offset 2...
*/
if (c1 == 0xB0)
c2 = *(volatile unsigned char *) (FLASH_BASE + 2);
else
c2 = *(volatile unsigned char *) (FLASH_BASE + 1);
c2 += (c1 << 8);
/*
* set it back to read mode
*/
*(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0xFF;
if (c2 == KFLASH_ID4)
gbFlashSize = KFLASH_SIZE4;
return c2;
}
static long flash_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
{
mutex_lock(&flash_mutex);
switch (cmd) {
case CMD_WRITE_DISABLE:
gbWriteBase64Enable = 0;
gbWriteEnable = 0;
break;
case CMD_WRITE_ENABLE:
gbWriteEnable = 1;
break;
case CMD_WRITE_BASE64K_ENABLE:
gbWriteBase64Enable = 1;
break;
default:
gbWriteBase64Enable = 0;
gbWriteEnable = 0;
mutex_unlock(&flash_mutex);
return -EINVAL;
}
mutex_unlock(&flash_mutex);
return 0;
}
static ssize_t flash_read(struct file *file, char __user *buf, size_t size,
loff_t *ppos)
{
ssize_t ret;
if (flashdebug)
printk(KERN_DEBUG "flash_read: flash_read: offset=0x%llx, "
"buffer=%p, count=0x%zx.\n", *ppos, buf, size);
/*
* We now lock against reads and writes. --rmk
*/
if (mutex_lock_interruptible(&nwflash_mutex))
return -ERESTARTSYS;
ret = simple_read_from_buffer(buf, size, ppos, (void *)FLASH_BASE, gbFlashSize);
mutex_unlock(&nwflash_mutex);
return ret;
}
static ssize_t flash_write(struct file *file, const char __user *buf,
size_t size, loff_t * ppos)
{
unsigned long p = *ppos;
unsigned int count = size;
int written;
int nBlock, temp, rc;
int i, j;
if (flashdebug)
printk("flash_write: offset=0x%lX, buffer=0x%p, count=0x%X.\n",
p, buf, count);
if (!gbWriteEnable)
return -EINVAL;
if (p < 64 * 1024 && (!gbWriteBase64Enable))
return -EINVAL;
/*
* check for out of range pos or count
*/
if (p >= gbFlashSize)
return count ? -ENXIO : 0;
if (count > gbFlashSize - p)
count = gbFlashSize - p;
if (!access_ok(VERIFY_READ, buf, count))
return -EFAULT;
/*
* We now lock against reads and writes. --rmk
*/
if (mutex_lock_interruptible(&nwflash_mutex))
return -ERESTARTSYS;
written = 0;
nBlock = (int) p >> 16; //block # of 64K bytes
/*
* # of 64K blocks to erase and write
*/
temp = ((int) (p + count) >> 16) - nBlock + 1;
/*
* write ends at exactly 64k boundary?
*/
if (((int) (p + count) & 0xFFFF) == 0)
temp -= 1;
if (flashdebug)
printk(KERN_DEBUG "flash_write: writing %d block(s) "
"starting at %d.\n", temp, nBlock);
for (; temp; temp--, nBlock++) {
if (flashdebug)
printk(KERN_DEBUG "flash_write: erasing block %d.\n", nBlock);
/*
* first we have to erase the block(s), where we will write...
*/
i = 0;
j = 0;
RetryBlock:
do {
rc = erase_block(nBlock);
i++;
} while (rc && i < 10);
if (rc) {
printk(KERN_ERR "flash_write: erase error %x\n", rc);
break;
}
if (flashdebug)
printk(KERN_DEBUG "flash_write: writing offset %lX, "
"from buf %p, bytes left %X.\n", p, buf,
count - written);
/*
* write_block will limit write to space left in this block
*/
rc = write_block(p, buf, count - written);
j++;
/*
* if somehow write verify failed? Can't happen??
*/
if (!rc) {
/*
* retry up to 10 times
*/
if (j < 10)
goto RetryBlock;
else
/*
* else quit with error...
*/
rc = -1;
}
if (rc < 0) {
printk(KERN_ERR "flash_write: write error %X\n", rc);
break;
}
p += rc;
buf += rc;
written += rc;
*ppos += rc;
if (flashdebug)
printk(KERN_DEBUG "flash_write: written 0x%X bytes OK.\n", written);
}
mutex_unlock(&nwflash_mutex);
return written;
}
/*
* The memory devices use the full 32/64 bits of the offset, and so we cannot
* check against negative addresses: they are ok. The return value is weird,
* though, in that case (0).
*
* also note that seeking relative to the "end of file" isn't supported:
* it has no meaning, so it returns -EINVAL.
*/
static loff_t flash_llseek(struct file *file, loff_t offset, int orig)
{
loff_t ret;
mutex_lock(&flash_mutex);
if (flashdebug)
printk(KERN_DEBUG "flash_llseek: offset=0x%X, orig=0x%X.\n",
(unsigned int) offset, orig);
ret = no_seek_end_llseek_size(file, offset, orig, gbFlashSize);
mutex_unlock(&flash_mutex);
return ret;
}
/*
* assume that main Write routine did the parameter checking...
* so just go ahead and erase, what requested!
*/
static int erase_block(int nBlock)
{
volatile unsigned int c1;
volatile unsigned char *pWritePtr;
unsigned long timeout;
int temp, temp1;
/*
* reset footbridge to the correct offset 0 (...0..3)
*/
*CSR_ROMWRITEREG = 0;
/*
* dummy ROM read
*/
c1 = *(volatile unsigned char *) (FLASH_BASE + 0x8000);
kick_open();
/*
* reset status if old errors
*/
*(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
/*
* erase a block...
* aim at the middle of a current block...
*/
pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + 0x8000 + (nBlock << 16)));
/*
* dummy read
*/
c1 = *pWritePtr;
kick_open();
/*
* erase
*/
*(volatile unsigned char *) pWritePtr = 0x20;
/*
* confirm
*/
*(volatile unsigned char *) pWritePtr = 0xD0;
/*
* wait 10 ms
*/
msleep(10);
/*
* wait while erasing in process (up to 10 sec)
*/
timeout = jiffies + 10 * HZ;
c1 = 0;
while (!(c1 & 0x80) && time_before(jiffies, timeout)) {
msleep(10);
/*
* read any address
*/
c1 = *(volatile unsigned char *) (pWritePtr);
// printk("Flash_erase: status=%X.\n",c1);
}
/*
* set flash for normal read access
*/
kick_open();
// *(volatile unsigned char*)(FLASH_BASE+0x8000) = 0xFF;
*(volatile unsigned char *) pWritePtr = 0xFF; //back to normal operation
/*
* check if erase errors were reported
*/
if (c1 & 0x20) {
printk(KERN_ERR "flash_erase: err at %p\n", pWritePtr);
/*
* reset error
*/
*(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
return -2;
}
/*
* just to make sure - verify if erased OK...
*/
msleep(10);
pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + (nBlock << 16)));
for (temp = 0; temp < 16 * 1024; temp++, pWritePtr += 4) {
if ((temp1 = *(volatile unsigned int *) pWritePtr) != 0xFFFFFFFF) {
printk(KERN_ERR "flash_erase: verify err at %p = %X\n",
pWritePtr, temp1);
return -1;
}
}
return 0;
}
/*
* write_block will limit number of bytes written to the space in this block
*/
static int write_block(unsigned long p, const char __user *buf, int count)
{
volatile unsigned int c1;
volatile unsigned int c2;
unsigned char *pWritePtr;
unsigned int uAddress;
unsigned int offset;
unsigned long timeout;
unsigned long timeout1;
pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + p));
/*
* check if write will end in this block....
*/
offset = p & 0xFFFF;
if (offset + count > 0x10000)
count = 0x10000 - offset;
/*
* wait up to 30 sec for this block
*/
timeout = jiffies + 30 * HZ;
for (offset = 0; offset < count; offset++, pWritePtr++) {
uAddress = (unsigned int) pWritePtr;
uAddress &= 0xFFFFFFFC;
if (__get_user(c2, buf + offset))
return -EFAULT;
WriteRetry:
/*
* dummy read
*/
c1 = *(volatile unsigned char *) (FLASH_BASE + 0x8000);
/*
* kick open the write gate
*/
kick_open();
/*
* program footbridge to the correct offset...0..3
*/
*CSR_ROMWRITEREG = (unsigned int) pWritePtr & 3;
/*
* write cmd
*/
*(volatile unsigned char *) (uAddress) = 0x40;
/*
* data to write
*/
*(volatile unsigned char *) (uAddress) = c2;
/*
* get status
*/
*(volatile unsigned char *) (FLASH_BASE + 0x10000) = 0x70;
c1 = 0;
/*
* wait up to 1 sec for this byte
*/
timeout1 = jiffies + 1 * HZ;
/*
* while not ready...
*/
while (!(c1 & 0x80) && time_before(jiffies, timeout1))
c1 = *(volatile unsigned char *) (FLASH_BASE + 0x8000);
/*
* if timeout getting status
*/
if (time_after_eq(jiffies, timeout1)) {
kick_open();
/*
* reset err
*/
*(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
goto WriteRetry;
}
/*
* switch on read access, as a default flash operation mode
*/
kick_open();
/*
* read access
*/
*(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0xFF;
/*
* if hardware reports an error writing, and not timeout -
* reset the chip and retry
*/
if (c1 & 0x10) {
kick_open();
/*
* reset err
*/
*(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
/*
* before timeout?
*/
if (time_before(jiffies, timeout)) {
if (flashdebug)
printk(KERN_DEBUG "write_block: Retrying write at 0x%X)n",
pWritePtr - FLASH_BASE);
/*
* wait couple ms
*/
msleep(10);
goto WriteRetry;
} else {
printk(KERN_ERR "write_block: timeout at 0x%X\n",
pWritePtr - FLASH_BASE);
/*
* return error -2
*/
return -2;
}
}
}
msleep(10);
pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + p));
for (offset = 0; offset < count; offset++) {
char c, c1;
if (__get_user(c, buf))
return -EFAULT;
buf++;
if ((c1 = *pWritePtr++) != c) {
printk(KERN_ERR "write_block: verify error at 0x%X (%02X!=%02X)\n",
pWritePtr - FLASH_BASE, c1, c);
return 0;
}
}
return count;
}
static void kick_open(void)
{
unsigned long flags;
/*
* we want to write a bit pattern XXX1 to Xilinx to enable
* the write gate, which will be open for about the next 2ms.
*/
raw_spin_lock_irqsave(&nw_gpio_lock, flags);
nw_cpld_modify(CPLD_FLASH_WR_ENABLE, CPLD_FLASH_WR_ENABLE);
raw_spin_unlock_irqrestore(&nw_gpio_lock, flags);
/*
* let the ISA bus to catch on...
*/
udelay(25);
}
static const struct file_operations flash_fops =
{
.owner = THIS_MODULE,
.llseek = flash_llseek,
.read = flash_read,
.write = flash_write,
.unlocked_ioctl = flash_ioctl,
};
static struct miscdevice flash_miscdev =
{
FLASH_MINOR,
"nwflash",
&flash_fops
};
static int __init nwflash_init(void)
{
int ret = -ENODEV;
if (machine_is_netwinder()) {
int id;
FLASH_BASE = ioremap(DC21285_FLASH, KFLASH_SIZE4);
if (!FLASH_BASE)
goto out;
id = get_flash_id();
if ((id != KFLASH_ID) && (id != KFLASH_ID4)) {
ret = -ENXIO;
iounmap((void *)FLASH_BASE);
printk("Flash: incorrect ID 0x%04X.\n", id);
goto out;
}
printk("Flash ROM driver v.%s, flash device ID 0x%04X, size %d Mb.\n",
NWFLASH_VERSION, id, gbFlashSize / (1024 * 1024));
ret = misc_register(&flash_miscdev);
if (ret < 0) {
iounmap((void *)FLASH_BASE);
}
}
out:
return ret;
}
static void __exit nwflash_exit(void)
{
misc_deregister(&flash_miscdev);
iounmap((void *)FLASH_BASE);
}
MODULE_LICENSE("GPL");
module_param(flashdebug, bool, 0644);
module_init(nwflash_init);
module_exit(nwflash_exit);
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