1/* $Id: flash.c,v 1.1.1.1 2007/08/03 18:52:55 Exp $
2 * flash.c: Allow mmap access to the OBP Flash, for OBP updates.
3 *
4 * Copyright (C) 1997  Eddie C. Dost  (ecd@skynet.be)
5 */
6
7#include <linux/module.h>
8#include <linux/types.h>
9#include <linux/errno.h>
10#include <linux/miscdevice.h>
11#include <linux/slab.h>
12#include <linux/fcntl.h>
13#include <linux/poll.h>
14#include <linux/init.h>
15#include <linux/smp_lock.h>
16#include <linux/spinlock.h>
17#include <linux/mm.h>
18
19#include <asm/system.h>
20#include <asm/uaccess.h>
21#include <asm/pgtable.h>
22#include <asm/io.h>
23#include <asm/sbus.h>
24#include <asm/ebus.h>
25#include <asm/upa.h>
26
27static DEFINE_SPINLOCK(flash_lock);
28static struct {
29	unsigned long read_base;	/* Physical read address */
30	unsigned long write_base;	/* Physical write address */
31	unsigned long read_size;	/* Size of read area */
32	unsigned long write_size;	/* Size of write area */
33	unsigned long busy;		/* In use? */
34} flash;
35
36#define FLASH_MINOR	152
37
38static int
39flash_mmap(struct file *file, struct vm_area_struct *vma)
40{
41	unsigned long addr;
42	unsigned long size;
43
44	spin_lock(&flash_lock);
45	if (flash.read_base == flash.write_base) {
46		addr = flash.read_base;
47		size = flash.read_size;
48	} else {
49		if ((vma->vm_flags & VM_READ) &&
50		    (vma->vm_flags & VM_WRITE)) {
51			spin_unlock(&flash_lock);
52			return -EINVAL;
53		}
54		if (vma->vm_flags & VM_READ) {
55			addr = flash.read_base;
56			size = flash.read_size;
57		} else if (vma->vm_flags & VM_WRITE) {
58			addr = flash.write_base;
59			size = flash.write_size;
60		} else {
61			spin_unlock(&flash_lock);
62			return -ENXIO;
63		}
64	}
65	spin_unlock(&flash_lock);
66
67	if ((vma->vm_pgoff << PAGE_SHIFT) > size)
68		return -ENXIO;
69	addr = vma->vm_pgoff + (addr >> PAGE_SHIFT);
70
71	if (vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT)) > size)
72		size = vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT));
73
74	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
75
76	if (io_remap_pfn_range(vma, vma->vm_start, addr, size, vma->vm_page_prot))
77		return -EAGAIN;
78
79	return 0;
80}
81
82static long long
83flash_llseek(struct file *file, long long offset, int origin)
84{
85	lock_kernel();
86	switch (origin) {
87		case 0:
88			file->f_pos = offset;
89			break;
90		case 1:
91			file->f_pos += offset;
92			if (file->f_pos > flash.read_size)
93				file->f_pos = flash.read_size;
94			break;
95		case 2:
96			file->f_pos = flash.read_size;
97			break;
98		default:
99			unlock_kernel();
100			return -EINVAL;
101	}
102	unlock_kernel();
103	return file->f_pos;
104}
105
106static ssize_t
107flash_read(struct file * file, char __user * buf,
108	   size_t count, loff_t *ppos)
109{
110	unsigned long p = file->f_pos;
111	int i;
112
113	if (count > flash.read_size - p)
114		count = flash.read_size - p;
115
116	for (i = 0; i < count; i++) {
117		u8 data = upa_readb(flash.read_base + p + i);
118		if (put_user(data, buf))
119			return -EFAULT;
120		buf++;
121	}
122
123	file->f_pos += count;
124	return count;
125}
126
127static int
128flash_open(struct inode *inode, struct file *file)
129{
130	if (test_and_set_bit(0, (void *)&flash.busy) != 0)
131		return -EBUSY;
132
133	return 0;
134}
135
136static int
137flash_release(struct inode *inode, struct file *file)
138{
139	spin_lock(&flash_lock);
140	flash.busy = 0;
141	spin_unlock(&flash_lock);
142
143	return 0;
144}
145
146static const struct file_operations flash_fops = {
147	/* no write to the Flash, use mmap
148	 * and play flash dependent tricks.
149	 */
150	.owner =	THIS_MODULE,
151	.llseek =	flash_llseek,
152	.read =		flash_read,
153	.mmap =		flash_mmap,
154	.open =		flash_open,
155	.release =	flash_release,
156};
157
158static struct miscdevice flash_dev = { FLASH_MINOR, "flash", &flash_fops };
159
160static int __init flash_init(void)
161{
162	struct sbus_bus *sbus;
163	struct sbus_dev *sdev = NULL;
164#ifdef CONFIG_PCI
165	struct linux_ebus *ebus;
166	struct linux_ebus_device *edev = NULL;
167	struct linux_prom_registers regs[2];
168	int len, nregs;
169#endif
170	int err;
171
172	for_all_sbusdev(sdev, sbus) {
173		if (!strcmp(sdev->prom_name, "flashprom")) {
174			if (sdev->reg_addrs[0].phys_addr == sdev->reg_addrs[1].phys_addr) {
175				flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
176					(((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
177				flash.read_size = sdev->reg_addrs[0].reg_size;
178				flash.write_base = flash.read_base;
179				flash.write_size = flash.read_size;
180			} else {
181				flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
182					(((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
183				flash.read_size = sdev->reg_addrs[0].reg_size;
184				flash.write_base = ((unsigned long)sdev->reg_addrs[1].phys_addr) |
185					(((unsigned long)sdev->reg_addrs[1].which_io)<<32UL);
186				flash.write_size = sdev->reg_addrs[1].reg_size;
187			}
188			flash.busy = 0;
189			break;
190		}
191	}
192	if (!sdev) {
193#ifdef CONFIG_PCI
194		const struct linux_prom_registers *ebus_regs;
195
196		for_each_ebus(ebus) {
197			for_each_ebusdev(edev, ebus) {
198				if (!strcmp(edev->prom_node->name, "flashprom"))
199					goto ebus_done;
200			}
201		}
202	ebus_done:
203		if (!edev)
204			return -ENODEV;
205
206		ebus_regs = of_get_property(edev->prom_node, "reg", &len);
207		if (!ebus_regs || (len % sizeof(regs[0])) != 0) {
208			printk("flash: Strange reg property size %d\n", len);
209			return -ENODEV;
210		}
211
212		nregs = len / sizeof(ebus_regs[0]);
213
214		flash.read_base = edev->resource[0].start;
215		flash.read_size = ebus_regs[0].reg_size;
216
217		if (nregs == 1) {
218			flash.write_base = edev->resource[0].start;
219			flash.write_size = ebus_regs[0].reg_size;
220		} else if (nregs == 2) {
221			flash.write_base = edev->resource[1].start;
222			flash.write_size = ebus_regs[1].reg_size;
223		} else {
224			printk("flash: Strange number of regs %d\n", nregs);
225			return -ENODEV;
226		}
227
228		flash.busy = 0;
229
230#else
231		return -ENODEV;
232#endif
233	}
234
235	printk("OBP Flash: RD %lx[%lx] WR %lx[%lx]\n",
236	       flash.read_base, flash.read_size,
237	       flash.write_base, flash.write_size);
238
239	err = misc_register(&flash_dev);
240	if (err) {
241		printk(KERN_ERR "flash: unable to get misc minor\n");
242		return err;
243	}
244
245	return 0;
246}
247
248static void __exit flash_cleanup(void)
249{
250	misc_deregister(&flash_dev);
251}
252
253module_init(flash_init);
254module_exit(flash_cleanup);
255MODULE_LICENSE("GPL");
256