drivers/sbus/char/jsflash.c - maze/linux - Git at Google

 /*
  * drivers/sbus/char/jsflash.c
  *
  *  Copyright (C) 1991, 1992  Linus Torvalds	(drivers/char/mem.c)
  *  Copyright (C) 1997  Eddie C. Dost		(drivers/sbus/char/flash.c)
  *  Copyright (C) 1997-2000 Pavel Machek <pavel@ucw.cz>   (drivers/block/nbd.c)
  *  Copyright (C) 1999-2000 Pete Zaitcev
  *
  * This driver is used to program OS into a Flash SIMM on
  * Krups and Espresso platforms.
  *
  * TODO: do not allow erase/programming if file systems are mounted.
  * TODO: Erase/program both banks of a 8MB SIMM.
  *
  * It is anticipated that programming an OS Flash will be a routine
  * procedure. In the same time it is exeedingly dangerous because
  * a user can program its OBP flash with OS image and effectively
  * kill the machine.
  *
  * This driver uses an interface different from Eddie's flash.c
  * as a silly safeguard.
  *
  * XXX The flash.c manipulates page caching characteristics in a certain
  * dubious way; also it assumes that remap_pfn_range() can remap
  * PCI bus locations, which may be false. ioremap() must be used
  * instead. We should discuss this.
  */

 #include <linux/module.h>
 #include <linux/smp_lock.h>
 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/miscdevice.h>
 #include <linux/fcntl.h>
 #include <linux/poll.h>
 #include <linux/init.h>
 #include <linux/string.h>
 #include <linux/genhd.h>
 #include <linux/blkdev.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include <asm/io.h>
 #include <asm/pcic.h>
 #include <asm/oplib.h>

 #include <asm/jsflash.h>		/* ioctl arguments. <linux/> ?? */
 #define JSFIDSZ		(sizeof(struct jsflash_ident_arg))
 #define JSFPRGSZ	(sizeof(struct jsflash_program_arg))

 /*
  * Our device numbers have no business in system headers.
  * The only thing a user knows is the device name /dev/jsflash.
  *
  * Block devices are laid out like this:
  *   minor+0	- Bootstrap, for 8MB SIMM 0x20400000[0x800000]
  *   minor+1	- Filesystem to mount, normally 0x20400400[0x7ffc00]
  *   minor+2	- Whole flash area for any case... 0x20000000[0x01000000]
  * Total 3 minors per flash device.
  *
  * It is easier to have static size vectors, so we define
  * a total minor range JSF_MAX, which must cover all minors.
  */
 /* character device */
 #define JSF_MINOR	178	/* 178 is registered with hpa */
 /* block device */
 #define JSF_MAX		 3	/* 3 minors wasted total so far. */
 #define JSF_NPART	 3	/* 3 minors per flash device */
 #define JSF_PART_BITS	 2	/* 2 bits of minors to cover JSF_NPART */
 #define JSF_PART_MASK	 0x3	/* 2 bits mask */

 /*
  * Access functions.
  * We could ioremap(), but it's easier this way.
  */
 static unsigned int jsf_inl(unsigned long addr)
 {
 	unsigned long retval;

 	__asm__ __volatile__("lda [%1] %2, %0\n\t" :
 				"=r" (retval) :
 				"r" (addr), "i" (ASI_M_BYPASS));
         return retval;
 }

 static void jsf_outl(unsigned long addr, __u32 data)
 {

 	__asm__ __volatile__("sta %0, [%1] %2\n\t" : :
 				"r" (data), "r" (addr), "i" (ASI_M_BYPASS) :
 				"memory");
 }

 /*
  * soft carrier
  */

 struct jsfd_part {
 	unsigned long dbase;
 	unsigned long dsize;
 };

 struct jsflash {
 	unsigned long base;
 	unsigned long size;
 	unsigned long busy;		/* In use? */
 	struct jsflash_ident_arg id;
 	/* int mbase; */		/* Minor base, typically zero */
 	struct jsfd_part dv[JSF_NPART];
 };

 /*
  * We do not map normal memory or obio as a safety precaution.
  * But offsets are real, for ease of userland programming.
  */
 #define JSF_BASE_TOP	0x30000000
 #define JSF_BASE_ALL	0x20000000

 #define JSF_BASE_JK	0x20400000

 /*
  */
 static struct gendisk *jsfd_disk[JSF_MAX];

 /*
  * Let's pretend we may have several of these...
  */
 static struct jsflash jsf0;

 /*
  * Wait for AMD to finish its embedded algorithm.
  * We use the Toggle bit DQ6 (0x40) because it does not
  * depend on the data value as /DATA bit DQ7 does.
  *
  * XXX Do we need any timeout here? So far it never hanged, beware broken hw.
  */
 static void jsf_wait(unsigned long p) {
 	unsigned int x1, x2;

 	for (;;) {
 		x1 = jsf_inl(p);
 		x2 = jsf_inl(p);
 		if ((x1 & 0x40404040) == (x2 & 0x40404040)) return;
 	}
 }

 /*
  * Programming will only work if Flash is clean,
  * we leave it to the programmer application.
  *
  * AMD must be programmed one byte at a time;
  * thus, Simple Tech SIMM must be written 4 bytes at a time.
  *
  * Write waits for the chip to become ready after the write
  * was finished. This is done so that application would read
  * consistent data after the write is done.
  */
 static void jsf_write4(unsigned long fa, u32 data) {

 	jsf_outl(fa, 0xAAAAAAAA);		/* Unlock 1 Write 1 */
 	jsf_outl(fa, 0x55555555);		/* Unlock 1 Write 2 */
 	jsf_outl(fa, 0xA0A0A0A0);		/* Byte Program */
 	jsf_outl(fa, data);

 	jsf_wait(fa);
 }

 /*
  */
 static void jsfd_read(char *buf, unsigned long p, size_t togo) {
 	union byte4 {
 		char s[4];
 		unsigned int n;
 	} b;

 	while (togo >= 4) {
 		togo -= 4;
 		b.n = jsf_inl(p);
 		memcpy(buf, b.s, 4);
 		p += 4;
 		buf += 4;
 	}
 }

 static void jsfd_do_request(struct request_queue *q)
 {
 	struct request *req;

 	req = blk_fetch_request(q);
 	while (req) {
 		struct jsfd_part *jdp = req->rq_disk->private_data;
 		unsigned long offset = blk_rq_pos(req) << 9;
 		size_t len = blk_rq_cur_bytes(req);
 		int err = -EIO;

 		if ((offset + len) > jdp->dsize)
 			goto end;

 		if (rq_data_dir(req) != READ) {
 			printk(KERN_ERR "jsfd: write\n");
 			goto end;
 		}

 		if ((jdp->dbase & 0xff000000) != 0x20000000) {
 			printk(KERN_ERR "jsfd: bad base %x\n", (int)jdp->dbase);
 			goto end;
 		}

 		jsfd_read(req->buffer, jdp->dbase + offset, len);
 		err = 0;
 	end:
 		if (!__blk_end_request_cur(req, err))
 			req = blk_fetch_request(q);
 	}
 }

 /*
  * 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 jsf_lseek(struct file * file, loff_t offset, int orig)
 {
 	loff_t ret;

 	lock_kernel();
 	switch (orig) {
 		case 0:
 			file->f_pos = offset;
 			ret = file->f_pos;
 			break;
 		case 1:
 			file->f_pos += offset;
 			ret = file->f_pos;
 			break;
 		default:
 			ret = -EINVAL;
 	}
 	unlock_kernel();
 	return ret;
 }

 /*
  * OS SIMM Cannot be read in other size but a 32bits word.
  */
 static ssize_t jsf_read(struct file * file, char __user * buf,
     size_t togo, loff_t *ppos)
 {
 	unsigned long p = *ppos;
 	char __user *tmp = buf;

 	union byte4 {
 		char s[4];
 		unsigned int n;
 	} b;

 	if (p < JSF_BASE_ALL || p >= JSF_BASE_TOP) {
 		return 0;
 	}

 	if ((p + togo) < p	/* wrap */
 	   || (p + togo) >= JSF_BASE_TOP) {
 		togo = JSF_BASE_TOP - p;
 	}

 	if (p < JSF_BASE_ALL && togo != 0) {
 #if 0 /* __bzero XXX */
 		size_t x = JSF_BASE_ALL - p;
 		if (x > togo) x = togo;
 		clear_user(tmp, x);
 		tmp += x;
 		p += x;
 		togo -= x;
 #else
 		/*
 		 * Implementation of clear_user() calls __bzero
 		 * without regard to modversions,
 		 * so we cannot build a module.
 		 */
 		return 0;
 #endif
 	}

 	while (togo >= 4) {
 		togo -= 4;
 		b.n = jsf_inl(p);
 		if (copy_to_user(tmp, b.s, 4))
 			return -EFAULT;
 		tmp += 4;
 		p += 4;
 	}

 	/*
 	 * XXX Small togo may remain if 1 byte is ordered.
 	 * It would be nice if we did a word size read and unpacked it.
 	 */

 	*ppos = p;
 	return tmp-buf;
 }

 static ssize_t jsf_write(struct file * file, const char __user * buf,
     size_t count, loff_t *ppos)
 {
 	return -ENOSPC;
 }

 /*
  */
 static int jsf_ioctl_erase(unsigned long arg)
 {
 	unsigned long p;

 	/* p = jsf0.base;	hits wrong bank */
 	p = 0x20400000;

 	jsf_outl(p, 0xAAAAAAAA);		/* Unlock 1 Write 1 */
 	jsf_outl(p, 0x55555555);		/* Unlock 1 Write 2 */
 	jsf_outl(p, 0x80808080);		/* Erase setup */
 	jsf_outl(p, 0xAAAAAAAA);		/* Unlock 2 Write 1 */
 	jsf_outl(p, 0x55555555);		/* Unlock 2 Write 2 */
 	jsf_outl(p, 0x10101010);		/* Chip erase */

 #if 0
 	/*
 	 * This code is ok, except that counter based timeout
 	 * has no place in this world. Let's just drop timeouts...
 	 */
 	{
 		int i;
 		__u32 x;
 		for (i = 0; i < 1000000; i++) {
 			x = jsf_inl(p);
 			if ((x & 0x80808080) == 0x80808080) break;
 		}
 		if ((x & 0x80808080) != 0x80808080) {
 			printk("jsf0: erase timeout with 0x%08x\n", x);
 		} else {
 			printk("jsf0: erase done with 0x%08x\n", x);
 		}
 	}
 #else
 	jsf_wait(p);
 #endif

 	return 0;
 }

 /*
  * Program a block of flash.
  * Very simple because we can do it byte by byte anyway.
  */
 static int jsf_ioctl_program(void __user *arg)
 {
 	struct jsflash_program_arg abuf;
 	char __user *uptr;
 	unsigned long p;
 	unsigned int togo;
 	union {
 		unsigned int n;
 		char s[4];
 	} b;

 	if (copy_from_user(&abuf, arg, JSFPRGSZ))
 		return -EFAULT;
 	p = abuf.off;
 	togo = abuf.size;
 	if ((togo & 3) || (p & 3)) return -EINVAL;

 	uptr = (char __user *) (unsigned long) abuf.data;
 	while (togo != 0) {
 		togo -= 4;
 		if (copy_from_user(&b.s[0], uptr, 4))
 			return -EFAULT;
 		jsf_write4(p, b.n);
 		p += 4;
 		uptr += 4;
 	}

 	return 0;
 }

 static long jsf_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 {
 	lock_kernel();
 	int error = -ENOTTY;
 	void __user *argp = (void __user *)arg;

 	if (!capable(CAP_SYS_ADMIN)) {
 		unlock_kernel();
 		return -EPERM;
 	}
 	switch (cmd) {
 	case JSFLASH_IDENT:
 		if (copy_to_user(argp, &jsf0.id, JSFIDSZ)) {
 			unlock_kernel();
 			return -EFAULT;
 		}
 		break;
 	case JSFLASH_ERASE:
 		error = jsf_ioctl_erase(arg);
 		break;
 	case JSFLASH_PROGRAM:
 		error = jsf_ioctl_program(argp);
 		break;
 	}

 	unlock_kernel();
 	return error;
 }

 static int jsf_mmap(struct file * file, struct vm_area_struct * vma)
 {
 	return -ENXIO;
 }

 static int jsf_open(struct inode * inode, struct file * filp)
 {
 	lock_kernel();
 	if (jsf0.base == 0) {
 		unlock_kernel();
 		return -ENXIO;
 	}
 	if (test_and_set_bit(0, (void *)&jsf0.busy) != 0) {
 		unlock_kernel();
 		return -EBUSY;
 	}

 	unlock_kernel();
 	return 0;	/* XXX What security? */
 }

 static int jsf_release(struct inode *inode, struct file *file)
 {
 	jsf0.busy = 0;
 	return 0;
 }

 static const struct file_operations jsf_fops = {
 	.owner =	THIS_MODULE,
 	.llseek =	jsf_lseek,
 	.read =		jsf_read,
 	.write =	jsf_write,
 	.unlocked_ioctl =	jsf_ioctl,
 	.mmap =		jsf_mmap,
 	.open =		jsf_open,
 	.release =	jsf_release,
 };

 static struct miscdevice jsf_dev = { JSF_MINOR, "jsflash", &jsf_fops };

 static const struct block_device_operations jsfd_fops = {
 	.owner =	THIS_MODULE,
 };

 static int jsflash_init(void)
 {
 	int rc;
 	struct jsflash *jsf;
 	int node;
 	char banner[128];
 	struct linux_prom_registers reg0;

 	node = prom_getchild(prom_root_node);
 	node = prom_searchsiblings(node, "flash-memory");
 	if (node != 0 && node != -1) {
 		if (prom_getproperty(node, "reg",
 		    (char *)&reg0, sizeof(reg0)) == -1) {
 			printk("jsflash: no \"reg\" property\n");
 			return -ENXIO;
 		}
 		if (reg0.which_io != 0) {
 			printk("jsflash: bus number nonzero: 0x%x:%x\n",
 			    reg0.which_io, reg0.phys_addr);
 			return -ENXIO;
 		}
 		/*
 		 * Flash may be somewhere else, for instance on Ebus.
 		 * So, don't do the following check for IIep flash space.
 		 */
 #if 0
 		if ((reg0.phys_addr >> 24) != 0x20) {
 			printk("jsflash: suspicious address: 0x%x:%x\n",
 			    reg0.which_io, reg0.phys_addr);
 			return -ENXIO;
 		}
 #endif
 		if ((int)reg0.reg_size <= 0) {
 			printk("jsflash: bad size 0x%x\n", (int)reg0.reg_size);
 			return -ENXIO;
 		}
 	} else {
 		/* XXX Remove this code once PROLL ID12 got widespread */
 		printk("jsflash: no /flash-memory node, use PROLL >= 12\n");
 		prom_getproperty(prom_root_node, "banner-name", banner, 128);
 		if (strcmp (banner, "JavaStation-NC") != 0 &&
 		    strcmp (banner, "JavaStation-E") != 0) {
 			return -ENXIO;
 		}
 		reg0.which_io = 0;
 		reg0.phys_addr = 0x20400000;
 		reg0.reg_size  = 0x00800000;
 	}

 	/* Let us be really paranoid for modifications to probing code. */
 	/* extern enum sparc_cpu sparc_cpu_model; */ /* in <asm/system.h> */
 	if (sparc_cpu_model != sun4m) {
 		/* We must be on sun4m because we use MMU Bypass ASI. */
 		return -ENXIO;
 	}

 	if (jsf0.base == 0) {
 		jsf = &jsf0;

 		jsf->base = reg0.phys_addr;
 		jsf->size = reg0.reg_size;

 		/* XXX Redo the userland interface. */
 		jsf->id.off = JSF_BASE_ALL;
 		jsf->id.size = 0x01000000;	/* 16M - all segments */
 		strcpy(jsf->id.name, "Krups_all");

 		jsf->dv[0].dbase = jsf->base;
 		jsf->dv[0].dsize = jsf->size;
 		jsf->dv[1].dbase = jsf->base + 1024;
 		jsf->dv[1].dsize = jsf->size - 1024;
 		jsf->dv[2].dbase = JSF_BASE_ALL;
 		jsf->dv[2].dsize = 0x01000000;

 		printk("Espresso Flash @0x%lx [%d MB]\n", jsf->base,
 		    (int) (jsf->size / (1024*1024)));
 	}

 	if ((rc = misc_register(&jsf_dev)) != 0) {
 		printk(KERN_ERR "jsf: unable to get misc minor %d\n",
 		    JSF_MINOR);
 		jsf0.base = 0;
 		return rc;
 	}

 	return 0;
 }

 static struct request_queue *jsf_queue;

 static int jsfd_init(void)
 {
 	static DEFINE_SPINLOCK(lock);
 	struct jsflash *jsf;
 	struct jsfd_part *jdp;
 	int err;
 	int i;

 	if (jsf0.base == 0)
 		return -ENXIO;

 	err = -ENOMEM;
 	for (i = 0; i < JSF_MAX; i++) {
 		struct gendisk *disk = alloc_disk(1);
 		if (!disk)
 			goto out;
 		jsfd_disk[i] = disk;
 	}

 	if (register_blkdev(JSFD_MAJOR, "jsfd")) {
 		err = -EIO;
 		goto out;
 	}

 	jsf_queue = blk_init_queue(jsfd_do_request, &lock);
 	if (!jsf_queue) {
 		err = -ENOMEM;
 		unregister_blkdev(JSFD_MAJOR, "jsfd");
 		goto out;
 	}

 	for (i = 0; i < JSF_MAX; i++) {
 		struct gendisk *disk = jsfd_disk[i];
 		if ((i & JSF_PART_MASK) >= JSF_NPART) continue;
 		jsf = &jsf0;	/* actually, &jsfv[i >> JSF_PART_BITS] */
 		jdp = &jsf->dv[i&JSF_PART_MASK];

 		disk->major = JSFD_MAJOR;
 		disk->first_minor = i;
 		sprintf(disk->disk_name, "jsfd%d", i);
 		disk->fops = &jsfd_fops;
 		set_capacity(disk, jdp->dsize >> 9);
 		disk->private_data = jdp;
 		disk->queue = jsf_queue;
 		add_disk(disk);
 		set_disk_ro(disk, 1);
 	}
 	return 0;
 out:
 	while (i--)
 		put_disk(jsfd_disk[i]);
 	return err;
 }

 MODULE_LICENSE("GPL");

 static int __init jsflash_init_module(void) {
 	int rc;

 	if ((rc = jsflash_init()) == 0) {
 		jsfd_init();
 		return 0;
 	}
 	return rc;
 }

 static void __exit jsflash_cleanup_module(void)
 {
 	int i;

 	for (i = 0; i < JSF_MAX; i++) {
 		if ((i & JSF_PART_MASK) >= JSF_NPART) continue;
 		del_gendisk(jsfd_disk[i]);
 		put_disk(jsfd_disk[i]);
 	}
 	if (jsf0.busy)
 		printk("jsf0: cleaning busy unit\n");
 	jsf0.base = 0;
 	jsf0.busy = 0;

 	misc_deregister(&jsf_dev);
 	unregister_blkdev(JSFD_MAJOR, "jsfd");
 	blk_cleanup_queue(jsf_queue);
 }

 module_init(jsflash_init_module);
 module_exit(jsflash_cleanup_module);
	/*
	* drivers/sbus/char/jsflash.c
	*
	* Copyright (C) 1991, 1992 Linus Torvalds (drivers/char/mem.c)
	* Copyright (C) 1997 Eddie C. Dost (drivers/sbus/char/flash.c)
	* Copyright (C) 1997-2000 Pavel Machek <pavel@ucw.cz> (drivers/block/nbd.c)
	* Copyright (C) 1999-2000 Pete Zaitcev
	*
	* This driver is used to program OS into a Flash SIMM on
	* Krups and Espresso platforms.
	*
	* TODO: do not allow erase/programming if file systems are mounted.
	* TODO: Erase/program both banks of a 8MB SIMM.
	*
	* It is anticipated that programming an OS Flash will be a routine
	* procedure. In the same time it is exeedingly dangerous because
	* a user can program its OBP flash with OS image and effectively
	* kill the machine.
	*
	* This driver uses an interface different from Eddie's flash.c
	* as a silly safeguard.
	*
	* XXX The flash.c manipulates page caching characteristics in a certain
	* dubious way; also it assumes that remap_pfn_range() can remap
	* PCI bus locations, which may be false. ioremap() must be used
	* instead. We should discuss this.
	*/

	#include <linux/module.h>
	#include <linux/smp_lock.h>
	#include <linux/types.h>
	#include <linux/errno.h>
	#include <linux/miscdevice.h>
	#include <linux/fcntl.h>
	#include <linux/poll.h>
	#include <linux/init.h>
	#include <linux/string.h>
	#include <linux/genhd.h>
	#include <linux/blkdev.h>
	#include <asm/uaccess.h>
	#include <asm/pgtable.h>
	#include <asm/io.h>
	#include <asm/pcic.h>
	#include <asm/oplib.h>

	#include <asm/jsflash.h> /* ioctl arguments. <linux/> ?? */
	#define JSFIDSZ (sizeof(struct jsflash_ident_arg))
	#define JSFPRGSZ (sizeof(struct jsflash_program_arg))

	/*
	* Our device numbers have no business in system headers.
	* The only thing a user knows is the device name /dev/jsflash.
	*
	* Block devices are laid out like this:
	* minor+0 - Bootstrap, for 8MB SIMM 0x20400000[0x800000]
	* minor+1 - Filesystem to mount, normally 0x20400400[0x7ffc00]
	* minor+2 - Whole flash area for any case... 0x20000000[0x01000000]
	* Total 3 minors per flash device.
	*
	* It is easier to have static size vectors, so we define
	* a total minor range JSF_MAX, which must cover all minors.
	*/
	/* character device */
	#define JSF_MINOR 178 /* 178 is registered with hpa */
	/* block device */
	#define JSF_MAX 3 /* 3 minors wasted total so far. */
	#define JSF_NPART 3 /* 3 minors per flash device */
	#define JSF_PART_BITS 2 /* 2 bits of minors to cover JSF_NPART */
	#define JSF_PART_MASK 0x3 /* 2 bits mask */

	/*
	* Access functions.
	* We could ioremap(), but it's easier this way.
	*/
	static unsigned int jsf_inl(unsigned long addr)
	{
	unsigned long retval;

	__asm__ __volatile__("lda [%1] %2, %0\n\t" :
	"=r" (retval) :
	"r" (addr), "i" (ASI_M_BYPASS));
	return retval;
	}

	static void jsf_outl(unsigned long addr, __u32 data)
	{

	__asm__ __volatile__("sta %0, [%1] %2\n\t" : :
	"r" (data), "r" (addr), "i" (ASI_M_BYPASS) :
	"memory");
	}

	/*
	* soft carrier
	*/

	struct jsfd_part {
	unsigned long dbase;
	unsigned long dsize;
	};

	struct jsflash {
	unsigned long base;
	unsigned long size;
	unsigned long busy; /* In use? */
	struct jsflash_ident_arg id;
	/* int mbase; / / Minor base, typically zero */
	struct jsfd_part dv[JSF_NPART];
	};

	/*
	* We do not map normal memory or obio as a safety precaution.
	* But offsets are real, for ease of userland programming.
	*/
	#define JSF_BASE_TOP 0x30000000
	#define JSF_BASE_ALL 0x20000000

	#define JSF_BASE_JK 0x20400000

	/*
	*/
	static struct gendisk *jsfd_disk[JSF_MAX];

	/*
	* Let's pretend we may have several of these...
	*/
	static struct jsflash jsf0;

	/*
	* Wait for AMD to finish its embedded algorithm.
	* We use the Toggle bit DQ6 (0x40) because it does not
	* depend on the data value as /DATA bit DQ7 does.
	*
	* XXX Do we need any timeout here? So far it never hanged, beware broken hw.
	*/
	static void jsf_wait(unsigned long p) {
	unsigned int x1, x2;

	for (;;) {
	x1 = jsf_inl(p);
	x2 = jsf_inl(p);
	if ((x1 & 0x40404040) == (x2 & 0x40404040)) return;
	}
	}

	/*
	* Programming will only work if Flash is clean,
	* we leave it to the programmer application.
	*
	* AMD must be programmed one byte at a time;
	* thus, Simple Tech SIMM must be written 4 bytes at a time.
	*
	* Write waits for the chip to become ready after the write
	* was finished. This is done so that application would read
	* consistent data after the write is done.
	*/
	static void jsf_write4(unsigned long fa, u32 data) {

	jsf_outl(fa, 0xAAAAAAAA); /* Unlock 1 Write 1 */
	jsf_outl(fa, 0x55555555); /* Unlock 1 Write 2 */
	jsf_outl(fa, 0xA0A0A0A0); /* Byte Program */
	jsf_outl(fa, data);

	jsf_wait(fa);
	}

	/*
	*/
	static void jsfd_read(char *buf, unsigned long p, size_t togo) {
	union byte4 {
	char s[4];
	unsigned int n;
	} b;

	while (togo >= 4) {
	togo -= 4;
	b.n = jsf_inl(p);
	memcpy(buf, b.s, 4);
	p += 4;
	buf += 4;
	}
	}

	static void jsfd_do_request(struct request_queue *q)
	{
	struct request *req;

	req = blk_fetch_request(q);
	while (req) {
	struct jsfd_part *jdp = req->rq_disk->private_data;
	unsigned long offset = blk_rq_pos(req) << 9;
	size_t len = blk_rq_cur_bytes(req);
	int err = -EIO;

	if ((offset + len) > jdp->dsize)
	goto end;

	if (rq_data_dir(req) != READ) {
	printk(KERN_ERR "jsfd: write\n");
	goto end;
	}

	if ((jdp->dbase & 0xff000000) != 0x20000000) {
	printk(KERN_ERR "jsfd: bad base %x\n", (int)jdp->dbase);
	goto end;
	}

	jsfd_read(req->buffer, jdp->dbase + offset, len);
	err = 0;
	end:
	if (!__blk_end_request_cur(req, err))
	req = blk_fetch_request(q);
	}
	}

	/*
	* 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 jsf_lseek(struct file * file, loff_t offset, int orig)
	{
	loff_t ret;

	lock_kernel();
	switch (orig) {
	case 0:
	file->f_pos = offset;
	ret = file->f_pos;
	break;
	case 1:
	file->f_pos += offset;
	ret = file->f_pos;
	break;
	default:
	ret = -EINVAL;
	}
	unlock_kernel();
	return ret;
	}

	/*
	* OS SIMM Cannot be read in other size but a 32bits word.
	*/
	static ssize_t jsf_read(struct file * file, char __user * buf,
	size_t togo, loff_t *ppos)
	{
	unsigned long p = *ppos;
	char __user *tmp = buf;

	union byte4 {
	char s[4];
	unsigned int n;
	} b;

	if (p < JSF_BASE_ALL \|\| p >= JSF_BASE_TOP) {
	return 0;
	}

	if ((p + togo) < p /* wrap */
	\|\| (p + togo) >= JSF_BASE_TOP) {
	togo = JSF_BASE_TOP - p;
	}

	if (p < JSF_BASE_ALL && togo != 0) {
	#if 0 /* __bzero XXX */
	size_t x = JSF_BASE_ALL - p;
	if (x > togo) x = togo;
	clear_user(tmp, x);
	tmp += x;
	p += x;
	togo -= x;
	#else
	/*
	* Implementation of clear_user() calls __bzero
	* without regard to modversions,
	* so we cannot build a module.
	*/
	return 0;
	#endif
	}

	while (togo >= 4) {
	togo -= 4;
	b.n = jsf_inl(p);
	if (copy_to_user(tmp, b.s, 4))
	return -EFAULT;
	tmp += 4;
	p += 4;
	}

	/*
	* XXX Small togo may remain if 1 byte is ordered.
	* It would be nice if we did a word size read and unpacked it.
	*/

	*ppos = p;
	return tmp-buf;
	}

	static ssize_t jsf_write(struct file * file, const char __user * buf,
	size_t count, loff_t *ppos)
	{
	return -ENOSPC;
	}

	/*
	*/
	static int jsf_ioctl_erase(unsigned long arg)
	{
	unsigned long p;

	/* p = jsf0.base; hits wrong bank */
	p = 0x20400000;

	jsf_outl(p, 0xAAAAAAAA); /* Unlock 1 Write 1 */
	jsf_outl(p, 0x55555555); /* Unlock 1 Write 2 */
	jsf_outl(p, 0x80808080); /* Erase setup */
	jsf_outl(p, 0xAAAAAAAA); /* Unlock 2 Write 1 */
	jsf_outl(p, 0x55555555); /* Unlock 2 Write 2 */
	jsf_outl(p, 0x10101010); /* Chip erase */

	#if 0
	/*
	* This code is ok, except that counter based timeout
	* has no place in this world. Let's just drop timeouts...
	*/
	{
	int i;
	__u32 x;
	for (i = 0; i < 1000000; i++) {
	x = jsf_inl(p);
	if ((x & 0x80808080) == 0x80808080) break;
	}
	if ((x & 0x80808080) != 0x80808080) {
	printk("jsf0: erase timeout with 0x%08x\n", x);
	} else {
	printk("jsf0: erase done with 0x%08x\n", x);
	}
	}
	#else
	jsf_wait(p);
	#endif

	return 0;
	}

	/*
	* Program a block of flash.
	* Very simple because we can do it byte by byte anyway.
	*/
	static int jsf_ioctl_program(void __user *arg)
	{
	struct jsflash_program_arg abuf;
	char __user *uptr;
	unsigned long p;
	unsigned int togo;
	union {
	unsigned int n;
	char s[4];
	} b;

	if (copy_from_user(&abuf, arg, JSFPRGSZ))
	return -EFAULT;
	p = abuf.off;
	togo = abuf.size;
	if ((togo & 3) \|\| (p & 3)) return -EINVAL;

	uptr = (char __user *) (unsigned long) abuf.data;
	while (togo != 0) {
	togo -= 4;
	if (copy_from_user(&b.s[0], uptr, 4))
	return -EFAULT;
	jsf_write4(p, b.n);
	p += 4;
	uptr += 4;
	}

	return 0;
	}

	static long jsf_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
	{
	lock_kernel();
	int error = -ENOTTY;
	void __user argp = (void __user )arg;

	if (!capable(CAP_SYS_ADMIN)) {
	unlock_kernel();
	return -EPERM;
	}
	switch (cmd) {
	case JSFLASH_IDENT:
	if (copy_to_user(argp, &jsf0.id, JSFIDSZ)) {
	unlock_kernel();
	return -EFAULT;
	}
	break;
	case JSFLASH_ERASE:
	error = jsf_ioctl_erase(arg);
	break;
	case JSFLASH_PROGRAM:
	error = jsf_ioctl_program(argp);
	break;
	}

	unlock_kernel();
	return error;
	}

	static int jsf_mmap(struct file * file, struct vm_area_struct * vma)
	{
	return -ENXIO;
	}

	static int jsf_open(struct inode * inode, struct file * filp)
	{
	lock_kernel();
	if (jsf0.base == 0) {
	unlock_kernel();
	return -ENXIO;
	}
	if (test_and_set_bit(0, (void *)&jsf0.busy) != 0) {
	unlock_kernel();
	return -EBUSY;
	}

	unlock_kernel();
	return 0; /* XXX What security? */
	}

	static int jsf_release(struct inode inode, struct file file)
	{
	jsf0.busy = 0;
	return 0;
	}

	static const struct file_operations jsf_fops = {
	.owner = THIS_MODULE,
	.llseek = jsf_lseek,
	.read = jsf_read,
	.write = jsf_write,
	.unlocked_ioctl = jsf_ioctl,
	.mmap = jsf_mmap,
	.open = jsf_open,
	.release = jsf_release,
	};

	static struct miscdevice jsf_dev = { JSF_MINOR, "jsflash", &jsf_fops };

	static const struct block_device_operations jsfd_fops = {
	.owner = THIS_MODULE,
	};

	static int jsflash_init(void)
	{
	int rc;
	struct jsflash *jsf;
	int node;
	char banner[128];
	struct linux_prom_registers reg0;

	node = prom_getchild(prom_root_node);
	node = prom_searchsiblings(node, "flash-memory");
	if (node != 0 && node != -1) {
	if (prom_getproperty(node, "reg",
	(char *)&reg0, sizeof(reg0)) == -1) {
	printk("jsflash: no \"reg\" property\n");
	return -ENXIO;
	}
	if (reg0.which_io != 0) {
	printk("jsflash: bus number nonzero: 0x%x:%x\n",
	reg0.which_io, reg0.phys_addr);
	return -ENXIO;
	}
	/*
	* Flash may be somewhere else, for instance on Ebus.
	* So, don't do the following check for IIep flash space.
	*/
	#if 0
	if ((reg0.phys_addr >> 24) != 0x20) {
	printk("jsflash: suspicious address: 0x%x:%x\n",
	reg0.which_io, reg0.phys_addr);
	return -ENXIO;
	}
	#endif
	if ((int)reg0.reg_size <= 0) {
	printk("jsflash: bad size 0x%x\n", (int)reg0.reg_size);
	return -ENXIO;
	}
	} else {
	/* XXX Remove this code once PROLL ID12 got widespread */
	printk("jsflash: no /flash-memory node, use PROLL >= 12\n");
	prom_getproperty(prom_root_node, "banner-name", banner, 128);
	if (strcmp (banner, "JavaStation-NC") != 0 &&
	strcmp (banner, "JavaStation-E") != 0) {
	return -ENXIO;
	}
	reg0.which_io = 0;
	reg0.phys_addr = 0x20400000;
	reg0.reg_size = 0x00800000;
	}

	/* Let us be really paranoid for modifications to probing code. */
	/* extern enum sparc_cpu sparc_cpu_model; / / in <asm/system.h> */
	if (sparc_cpu_model != sun4m) {
	/* We must be on sun4m because we use MMU Bypass ASI. */
	return -ENXIO;
	}

	if (jsf0.base == 0) {
	jsf = &jsf0;

	jsf->base = reg0.phys_addr;
	jsf->size = reg0.reg_size;

	/* XXX Redo the userland interface. */
	jsf->id.off = JSF_BASE_ALL;
	jsf->id.size = 0x01000000; /* 16M - all segments */
	strcpy(jsf->id.name, "Krups_all");

	jsf->dv[0].dbase = jsf->base;
	jsf->dv[0].dsize = jsf->size;
	jsf->dv[1].dbase = jsf->base + 1024;
	jsf->dv[1].dsize = jsf->size - 1024;
	jsf->dv[2].dbase = JSF_BASE_ALL;
	jsf->dv[2].dsize = 0x01000000;

	printk("Espresso Flash @0x%lx [%d MB]\n", jsf->base,
	(int) (jsf->size / (1024*1024)));
	}

	if ((rc = misc_register(&jsf_dev)) != 0) {
	printk(KERN_ERR "jsf: unable to get misc minor %d\n",
	JSF_MINOR);
	jsf0.base = 0;
	return rc;
	}

	return 0;
	}

	static struct request_queue *jsf_queue;

	static int jsfd_init(void)
	{
	static DEFINE_SPINLOCK(lock);
	struct jsflash *jsf;
	struct jsfd_part *jdp;
	int err;
	int i;

	if (jsf0.base == 0)
	return -ENXIO;

	err = -ENOMEM;
	for (i = 0; i < JSF_MAX; i++) {
	struct gendisk *disk = alloc_disk(1);
	if (!disk)
	goto out;
	jsfd_disk[i] = disk;
	}

	if (register_blkdev(JSFD_MAJOR, "jsfd")) {
	err = -EIO;
	goto out;
	}

	jsf_queue = blk_init_queue(jsfd_do_request, &lock);
	if (!jsf_queue) {
	err = -ENOMEM;
	unregister_blkdev(JSFD_MAJOR, "jsfd");
	goto out;
	}

	for (i = 0; i < JSF_MAX; i++) {
	struct gendisk *disk = jsfd_disk[i];
	if ((i & JSF_PART_MASK) >= JSF_NPART) continue;
	jsf = &jsf0; /* actually, &jsfv[i >> JSF_PART_BITS] */
	jdp = &jsf->dv[i&JSF_PART_MASK];

	disk->major = JSFD_MAJOR;
	disk->first_minor = i;
	sprintf(disk->disk_name, "jsfd%d", i);
	disk->fops = &jsfd_fops;
	set_capacity(disk, jdp->dsize >> 9);
	disk->private_data = jdp;
	disk->queue = jsf_queue;
	add_disk(disk);
	set_disk_ro(disk, 1);
	}
	return 0;
	out:
	while (i--)
	put_disk(jsfd_disk[i]);
	return err;
	}

	MODULE_LICENSE("GPL");

	static int __init jsflash_init_module(void) {
	int rc;

	if ((rc = jsflash_init()) == 0) {
	jsfd_init();
	return 0;
	}
	return rc;
	}

	static void __exit jsflash_cleanup_module(void)
	{
	int i;

	for (i = 0; i < JSF_MAX; i++) {
	if ((i & JSF_PART_MASK) >= JSF_NPART) continue;
	del_gendisk(jsfd_disk[i]);
	put_disk(jsfd_disk[i]);
	}
	if (jsf0.busy)
	printk("jsf0: cleaning busy unit\n");
	jsf0.base = 0;
	jsf0.busy = 0;

	misc_deregister(&jsf_dev);
	unregister_blkdev(JSFD_MAJOR, "jsfd");
	blk_cleanup_queue(jsf_queue);
	}

	module_init(jsflash_init_module);
	module_exit(jsflash_cleanup_module);