[mirror_ubuntu-hirsute-kernel.git] / drivers / sbus / char / flash.c

// SPDX-License-Identifier: GPL-2.0-only
/* flash.c: Allow mmap access to the OBP Flash, for OBP updates.
 *
 * Copyright (C) 1997  Eddie C. Dost  (ecd@skynet.be)
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/fcntl.h>
#include <linux/poll.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/of.h>
#include <linux/of_device.h>

#include <linux/uaccess.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/upa.h>

static DEFINE_MUTEX(flash_mutex);
static DEFINE_SPINLOCK(flash_lock);
static struct {
	unsigned long read_base;	/* Physical read address */
	unsigned long write_base;	/* Physical write address */
	unsigned long read_size;	/* Size of read area */
	unsigned long write_size;	/* Size of write area */
	unsigned long busy;		/* In use? */
} flash;

#define FLASH_MINOR	152

static int
flash_mmap(struct file *file, struct vm_area_struct *vma)
{
	unsigned long addr;
	unsigned long size;

	spin_lock(&flash_lock);
	if (flash.read_base == flash.write_base) {
		addr = flash.read_base;
		size = flash.read_size;
	} else {
		if ((vma->vm_flags & VM_READ) &&
		    (vma->vm_flags & VM_WRITE)) {
			spin_unlock(&flash_lock);
			return -EINVAL;
		}
		if (vma->vm_flags & VM_READ) {
			addr = flash.read_base;
			size = flash.read_size;
		} else if (vma->vm_flags & VM_WRITE) {
			addr = flash.write_base;
			size = flash.write_size;
		} else {
			spin_unlock(&flash_lock);
			return -ENXIO;
		}
	}
	spin_unlock(&flash_lock);

	if ((vma->vm_pgoff << PAGE_SHIFT) > size)
		return -ENXIO;
	addr = vma->vm_pgoff + (addr >> PAGE_SHIFT);

	if (vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT)) > size)
		size = vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT));

	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	if (io_remap_pfn_range(vma, vma->vm_start, addr, size, vma->vm_page_prot))
		return -EAGAIN;
		
	return 0;
}

static long long
flash_llseek(struct file *file, long long offset, int origin)
{
	mutex_lock(&flash_mutex);
	switch (origin) {
		case 0:
			file->f_pos = offset;
			break;
		case 1:
			file->f_pos += offset;
			if (file->f_pos > flash.read_size)
				file->f_pos = flash.read_size;
			break;
		case 2:
			file->f_pos = flash.read_size;
			break;
		default:
			mutex_unlock(&flash_mutex);
			return -EINVAL;
	}
	mutex_unlock(&flash_mutex);
	return file->f_pos;
}

static ssize_t
flash_read(struct file * file, char __user * buf,
	   size_t count, loff_t *ppos)
{
	loff_t p = *ppos;
	int i;

	if (count > flash.read_size - p)
		count = flash.read_size - p;

	for (i = 0; i < count; i++) {
		u8 data = upa_readb(flash.read_base + p + i);
		if (put_user(data, buf))
			return -EFAULT;
		buf++;
	}

	*ppos += count;
	return count;
}

static int
flash_open(struct inode *inode, struct file *file)
{
	mutex_lock(&flash_mutex);
	if (test_and_set_bit(0, (void *)&flash.busy) != 0) {
		mutex_unlock(&flash_mutex);
		return -EBUSY;
	}

	mutex_unlock(&flash_mutex);
	return 0;
}

static int
flash_release(struct inode *inode, struct file *file)
{
	spin_lock(&flash_lock);
	flash.busy = 0;
	spin_unlock(&flash_lock);

	return 0;
}

static const struct file_operations flash_fops = {
	/* no write to the Flash, use mmap
	 * and play flash dependent tricks.
	 */
	.owner =	THIS_MODULE,
	.llseek =	flash_llseek,
	.read =		flash_read,
	.mmap =		flash_mmap,
	.open =		flash_open,
	.release =	flash_release,
};

static struct miscdevice flash_dev = { FLASH_MINOR, "flash", &flash_fops };

static int flash_probe(struct platform_device *op)
{
	struct device_node *dp = op->dev.of_node;
	struct device_node *parent;

	parent = dp->parent;

	if (!of_node_name_eq(parent, "sbus") &&
	    !of_node_name_eq(parent, "sbi") &&
	    !of_node_name_eq(parent, "ebus"))
		return -ENODEV;

	flash.read_base = op->resource[0].start;
	flash.read_size = resource_size(&op->resource[0]);
	if (op->resource[1].flags) {
		flash.write_base = op->resource[1].start;
		flash.write_size = resource_size(&op->resource[1]);
	} else {
		flash.write_base = op->resource[0].start;
		flash.write_size = resource_size(&op->resource[0]);
	}
	flash.busy = 0;

	printk(KERN_INFO "%pOF: OBP Flash, RD %lx[%lx] WR %lx[%lx]\n",
	       op->dev.of_node,
	       flash.read_base, flash.read_size,
	       flash.write_base, flash.write_size);

	return misc_register(&flash_dev);
}

static int flash_remove(struct platform_device *op)
{
	misc_deregister(&flash_dev);

	return 0;
}

static const struct of_device_id flash_match[] = {
	{
		.name = "flashprom",
	},
	{},
};
MODULE_DEVICE_TABLE(of, flash_match);

static struct platform_driver flash_driver = {
	.driver = {
		.name = "flash",
		.of_match_table = flash_match,
	},
	.probe		= flash_probe,
	.remove		= flash_remove,
};

module_platform_driver(flash_driver);

MODULE_LICENSE("GPL");
Commit	Line	Data
09c434b8	1	// SPDX-License-Identifier: GPL-2.0-only
a9540d34	2	/* flash.c: Allow mmap access to the OBP Flash, for OBP updates.
1da177e4 LT	3	*
	4	* Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be)
	5	*/
	6
1da177e4 LT	7	#include <linux/module.h>
	8	#include <linux/types.h>
	9	#include <linux/errno.h>
	10	#include <linux/miscdevice.h>
1da177e4 LT	11	#include <linux/fcntl.h>
1da177e4 LT	12	#include <linux/poll.h>
a3108ca2	13	#include <linux/mutex.h>
1da177e4	14	#include <linux/spinlock.h>
8a73709e	15	#include <linux/mm.h>
a9540d34 DM	16	#include <linux/of.h>
a9540d34 DM	17	#include <linux/of_device.h>
1da177e4	18
7c0f6ba6	19	#include <linux/uaccess.h>
1da177e4 LT	20	#include <asm/pgtable.h>
1da177e4 LT	21	#include <asm/io.h>
1da177e4 LT	22	#include <asm/upa.h>
1da177e4 LT	23
a3108ca2	24	static DEFINE_MUTEX(flash_mutex);
1da177e4 LT	25	static DEFINE_SPINLOCK(flash_lock);
	26	static struct {
	27	unsigned long read_base; /* Physical read address */
	28	unsigned long write_base; /* Physical write address */
	29	unsigned long read_size; /* Size of read area */
	30	unsigned long write_size; /* Size of write area */
	31	unsigned long busy; /* In use? */
	32	} flash;
	33
	34	#define FLASH_MINOR 152
	35
	36	static int
	37	flash_mmap(struct file file, struct vm_area_struct vma)
	38	{
	39	unsigned long addr;
	40	unsigned long size;
	41
	42	spin_lock(&flash_lock);
	43	if (flash.read_base == flash.write_base) {
	44	addr = flash.read_base;
	45	size = flash.read_size;
	46	} else {
	47	if ((vma->vm_flags & VM_READ) &&
	48	(vma->vm_flags & VM_WRITE)) {
	49	spin_unlock(&flash_lock);
	50	return -EINVAL;
	51	}
	52	if (vma->vm_flags & VM_READ) {
	53	addr = flash.read_base;
	54	size = flash.read_size;
	55	} else if (vma->vm_flags & VM_WRITE) {
	56	addr = flash.write_base;
	57	size = flash.write_size;
	58	} else {
	59	spin_unlock(&flash_lock);
	60	return -ENXIO;
	61	}
	62	}
	63	spin_unlock(&flash_lock);
	64
	65	if ((vma->vm_pgoff << PAGE_SHIFT) > size)
	66	return -ENXIO;
	67	addr = vma->vm_pgoff + (addr >> PAGE_SHIFT);
	68
	69	if (vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT)) > size)
	70	size = vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT));
	71
14778d90	72	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1da177e4 LT	73
	74	if (io_remap_pfn_range(vma, vma->vm_start, addr, size, vma->vm_page_prot))
	75	return -EAGAIN;
	76
	77	return 0;
	78	}
	79
	80	static long long
	81	flash_llseek(struct file *file, long long offset, int origin)
	82	{
a3108ca2	83	mutex_lock(&flash_mutex);
1da177e4 LT	84	switch (origin) {
	85	case 0:
	86	file->f_pos = offset;
	87	break;
	88	case 1:
	89	file->f_pos += offset;
	90	if (file->f_pos > flash.read_size)
	91	file->f_pos = flash.read_size;
	92	break;
	93	case 2:
	94	file->f_pos = flash.read_size;
	95	break;
	96	default:
a3108ca2	97	mutex_unlock(&flash_mutex);
1da177e4 LT	98	return -EINVAL;
1da177e4 LT	99	}
a3108ca2	100	mutex_unlock(&flash_mutex);
1da177e4 LT	101	return file->f_pos;
	102	}
	103
	104	static ssize_t
	105	flash_read(struct file * file, char __user * buf,
	106	size_t count, loff_t *ppos)
	107	{
be94bbb5	108	loff_t p = *ppos;
1da177e4	109	int i;
be94bbb5	110
1da177e4 LT	111	if (count > flash.read_size - p)
	112	count = flash.read_size - p;
	113
	114	for (i = 0; i < count; i++) {
	115	u8 data = upa_readb(flash.read_base + p + i);
	116	if (put_user(data, buf))
	117	return -EFAULT;
	118	buf++;
	119	}
	120
be94bbb5	121	*ppos += count;
1da177e4 LT	122	return count;
	123	}
	124
	125	static int
	126	flash_open(struct inode inode, struct file file)
	127	{
a3108ca2	128	mutex_lock(&flash_mutex);
78abb6ac	129	if (test_and_set_bit(0, (void *)&flash.busy) != 0) {
a3108ca2	130	mutex_unlock(&flash_mutex);
1da177e4	131	return -EBUSY;
78abb6ac	132	}
1da177e4	133
a3108ca2	134	mutex_unlock(&flash_mutex);
1da177e4 LT	135	return 0;
	136	}
	137
	138	static int
	139	flash_release(struct inode inode, struct file file)
	140	{
	141	spin_lock(&flash_lock);
	142	flash.busy = 0;
	143	spin_unlock(&flash_lock);
	144
	145	return 0;
	146	}
	147
00977a59	148	static const struct file_operations flash_fops = {
1da177e4 LT	149	/* no write to the Flash, use mmap
	150	* and play flash dependent tricks.
	151	*/
	152	.owner = THIS_MODULE,
	153	.llseek = flash_llseek,
	154	.read = flash_read,
	155	.mmap = flash_mmap,
	156	.open = flash_open,
	157	.release = flash_release,
	158	};
	159
	160	static struct miscdevice flash_dev = { FLASH_MINOR, "flash", &flash_fops };
	161
082a2004	162	static int flash_probe(struct platform_device *op)
1da177e4	163	{
61c7a080	164	struct device_node *dp = op->dev.of_node;
a9540d34	165	struct device_node *parent;
1da177e4	166
a9540d34	167	parent = dp->parent;
1da177e4	168
91abe6b2 RH	169	if (!of_node_name_eq(parent, "sbus") &&
	170	!of_node_name_eq(parent, "sbi") &&
	171	!of_node_name_eq(parent, "ebus"))
1da177e4	172	return -ENODEV;
a9540d34 DM	173
	174	flash.read_base = op->resource[0].start;
	175	flash.read_size = resource_size(&op->resource[0]);
	176	if (op->resource[1].flags) {
	177	flash.write_base = op->resource[1].start;
	178	flash.write_size = resource_size(&op->resource[1]);
	179	} else {
	180	flash.write_base = op->resource[0].start;
	181	flash.write_size = resource_size(&op->resource[0]);
1da177e4	182	}
a9540d34	183	flash.busy = 0;
1da177e4	184
8cd3ec51 RH	185	printk(KERN_INFO "%pOF: OBP Flash, RD %lx[%lx] WR %lx[%lx]\n",
8cd3ec51 RH	186	op->dev.of_node,
1da177e4 LT	187	flash.read_base, flash.read_size,
	188	flash.write_base, flash.write_size);
	189
a9540d34 DM	190	return misc_register(&flash_dev);
	191	}
	192
082a2004	193	static int flash_remove(struct platform_device *op)
a9540d34 DM	194	{
a9540d34 DM	195	misc_deregister(&flash_dev);
1da177e4 LT	196
	197	return 0;
	198	}
	199
fd098316	200	static const struct of_device_id flash_match[] = {
a9540d34 DM	201	{
	202	.name = "flashprom",
	203	},
	204	{},
	205	};
	206	MODULE_DEVICE_TABLE(of, flash_match);
	207
4ebb24f7	208	static struct platform_driver flash_driver = {
4018294b GL	209	.driver = {
4018294b GL	210	.name = "flash",
4018294b GL	211	.of_match_table = flash_match,
4018294b GL	212	},
a9540d34	213	.probe = flash_probe,
082a2004	214	.remove = flash_remove,
a9540d34 DM	215	};
a9540d34 DM	216
dbf2b92d	217	module_platform_driver(flash_driver);
1da177e4	218
1da177e4	219	MODULE_LICENSE("GPL");