[linux-2.6-block.git] / arch / powerpc / platforms / pseries / scanlog.c

/*
 *  c 2001 PPC 64 Team, IBM Corp
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 *
 * scan-log-data driver for PPC64  Todd Inglett <tinglett@vnet.ibm.com>
 *
 * When ppc64 hardware fails the service processor dumps internal state
 * of the system.  After a reboot the operating system can access a dump
 * of this data using this driver.  A dump exists if the device-tree
 * /chosen/ibm,scan-log-data property exists.
 *
 * This driver exports /proc/powerpc/scan-log-dump which can be read.
 * The driver supports only sequential reads.
 *
 * The driver looks at a write to the driver for the single word "reset".
 * If given, the driver will reset the scanlog so the platform can free it.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <asm/rtas.h>
#include <asm/prom.h>

#define MODULE_VERS "1.0"
#define MODULE_NAME "scanlog"

/* Status returns from ibm,scan-log-dump */
#define SCANLOG_COMPLETE 0
#define SCANLOG_HWERROR -1
#define SCANLOG_CONTINUE 1


static unsigned int ibm_scan_log_dump;			/* RTAS token */
static struct proc_dir_entry *proc_ppc64_scan_log_dump;	/* The proc file */

static ssize_t scanlog_read(struct file *file, char __user *buf,
			    size_t count, loff_t *ppos)
{
	struct proc_dir_entry *dp = PDE(file_inode(file));
	unsigned int *data = (unsigned int *)dp->data;
	int status;
	unsigned long len, off;
	unsigned int wait_time;

	if (count > RTAS_DATA_BUF_SIZE)
		count = RTAS_DATA_BUF_SIZE;

	if (count < 1024) {
		/* This is the min supported by this RTAS call.  Rather
		 * than do all the buffering we insist the user code handle
		 * larger reads.  As long as cp works... :)
		 */
		printk(KERN_ERR "scanlog: cannot perform a small read (%ld)\n", count);
		return -EINVAL;
	}

	if (!access_ok(VERIFY_WRITE, buf, count))
		return -EFAULT;

	for (;;) {
		wait_time = 500;	/* default wait if no data */
		spin_lock(&rtas_data_buf_lock);
		memcpy(rtas_data_buf, data, RTAS_DATA_BUF_SIZE);
		status = rtas_call(ibm_scan_log_dump, 2, 1, NULL,
				   (u32) __pa(rtas_data_buf), (u32) count);
		memcpy(data, rtas_data_buf, RTAS_DATA_BUF_SIZE);
		spin_unlock(&rtas_data_buf_lock);

		pr_debug("scanlog: status=%d, data[0]=%x, data[1]=%x, " \
			 "data[2]=%x\n", status, data[0], data[1], data[2]);
		switch (status) {
		    case SCANLOG_COMPLETE:
			pr_debug("scanlog: hit eof\n");
			return 0;
		    case SCANLOG_HWERROR:
			pr_debug("scanlog: hardware error reading data\n");
			return -EIO;
		    case SCANLOG_CONTINUE:
			/* We may or may not have data yet */
			len = data[1];
			off = data[2];
			if (len > 0) {
				if (copy_to_user(buf, ((char *)data)+off, len))
					return -EFAULT;
				return len;
			}
			/* Break to sleep default time */
			break;
		    default:
			/* Assume extended busy */
			wait_time = rtas_busy_delay_time(status);
			if (!wait_time) {
				printk(KERN_ERR "scanlog: unknown error " \
				       "from rtas: %d\n", status);
				return -EIO;
			}
		}
		/* Apparently no data yet.  Wait and try again. */
		msleep_interruptible(wait_time);
	}
	/*NOTREACHED*/
}

static ssize_t scanlog_write(struct file * file, const char __user * buf,
			     size_t count, loff_t *ppos)
{
	char stkbuf[20];
	int status;

	if (count > 19) count = 19;
	if (copy_from_user (stkbuf, buf, count)) {
		return -EFAULT;
	}
	stkbuf[count] = 0;

	if (buf) {
		if (strncmp(stkbuf, "reset", 5) == 0) {
			pr_debug("scanlog: reset scanlog\n");
			status = rtas_call(ibm_scan_log_dump, 2, 1, NULL, 0, 0);
			pr_debug("scanlog: rtas returns %d\n", status);
		}
	}
	return count;
}

static int scanlog_open(struct inode * inode, struct file * file)
{
	struct proc_dir_entry *dp = PDE(inode);
	unsigned int *data = (unsigned int *)dp->data;

	if (data[0] != 0) {
		/* This imperfect test stops a second copy of the
		 * data (or a reset while data is being copied)
		 */
		return -EBUSY;
	}

	data[0] = 0;	/* re-init so we restart the scan */

	return 0;
}

static int scanlog_release(struct inode * inode, struct file * file)
{
	struct proc_dir_entry *dp = PDE(inode);
	unsigned int *data = (unsigned int *)dp->data;

	data[0] = 0;

	return 0;
}

const struct file_operations scanlog_fops = {
	.owner		= THIS_MODULE,
	.read		= scanlog_read,
	.write		= scanlog_write,
	.open		= scanlog_open,
	.release	= scanlog_release,
	.llseek		= noop_llseek,
};

static int __init scanlog_init(void)
{
	struct proc_dir_entry *ent;
	void *data;
	int err = -ENOMEM;

	ibm_scan_log_dump = rtas_token("ibm,scan-log-dump");
	if (ibm_scan_log_dump == RTAS_UNKNOWN_SERVICE)
		return -ENODEV;

	/* Ideally we could allocate a buffer < 4G */
	data = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
	if (!data)
		goto err;

	ent = proc_create_data("powerpc/rtas/scan-log-dump", S_IRUSR, NULL,
			       &scanlog_fops, data);
	if (!ent)
		goto err;

	proc_ppc64_scan_log_dump = ent;

	return 0;
err:
	kfree(data);
	return err;
}

static void __exit scanlog_cleanup(void)
{
	if (proc_ppc64_scan_log_dump) {
		kfree(proc_ppc64_scan_log_dump->data);
		remove_proc_entry("scan-log-dump", proc_ppc64_scan_log_dump->parent);
	}
}

module_init(scanlog_init);
module_exit(scanlog_cleanup);
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* c 2001 PPC 64 Team, IBM Corp
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation; either version
	7	* 2 of the License, or (at your option) any later version.
	8	*
	9	* scan-log-data driver for PPC64 Todd Inglett <tinglett@vnet.ibm.com>
	10	*
	11	* When ppc64 hardware fails the service processor dumps internal state
	12	* of the system. After a reboot the operating system can access a dump
	13	* of this data using this driver. A dump exists if the device-tree
	14	* /chosen/ibm,scan-log-data property exists.
	15	*
188917e1	16	* This driver exports /proc/powerpc/scan-log-dump which can be read.
1da177e4 LT	17	* The driver supports only sequential reads.
	18	*
	19	* The driver looks at a write to the driver for the single word "reset".
	20	* If given, the driver will reset the scanlog so the platform can free it.
	21	*/
	22
	23	#include <linux/module.h>
	24	#include <linux/types.h>
	25	#include <linux/errno.h>
	26	#include <linux/proc_fs.h>
	27	#include <linux/init.h>
0287ebed	28	#include <linux/delay.h>
5a0e3ad6	29	#include <linux/slab.h>
1da177e4 LT	30	#include <asm/uaccess.h>
	31	#include <asm/rtas.h>
	32	#include <asm/prom.h>
	33
	34	#define MODULE_VERS "1.0"
	35	#define MODULE_NAME "scanlog"
	36
	37	/* Status returns from ibm,scan-log-dump */
	38	#define SCANLOG_COMPLETE 0
	39	#define SCANLOG_HWERROR -1
	40	#define SCANLOG_CONTINUE 1
	41
1da177e4	42
1da177e4 LT	43	static unsigned int ibm_scan_log_dump; /* RTAS token */
	44	static struct proc_dir_entry proc_ppc64_scan_log_dump; / The proc file */
	45
efa54579	46	static ssize_t scanlog_read(struct file file, char __user buf,
1da177e4 LT	47	size_t count, loff_t *ppos)
1da177e4 LT	48	{
496ad9aa AV	49	struct proc_dir_entry *dp = PDE(file_inode(file));
496ad9aa AV	50	unsigned int data = (unsigned int )dp->data;
1da177e4 LT	51	int status;
	52	unsigned long len, off;
	53	unsigned int wait_time;
	54
1da177e4 LT	55	if (count > RTAS_DATA_BUF_SIZE)
	56	count = RTAS_DATA_BUF_SIZE;
	57
	58	if (count < 1024) {
	59	/* This is the min supported by this RTAS call. Rather
	60	* than do all the buffering we insist the user code handle
	61	* larger reads. As long as cp works... :)
	62	*/
	63	printk(KERN_ERR "scanlog: cannot perform a small read (%ld)\n", count);
	64	return -EINVAL;
	65	}
	66
	67	if (!access_ok(VERIFY_WRITE, buf, count))
	68	return -EFAULT;
	69
	70	for (;;) {
0287ebed	71	wait_time = 500; /* default wait if no data */
1da177e4 LT	72	spin_lock(&rtas_data_buf_lock);
	73	memcpy(rtas_data_buf, data, RTAS_DATA_BUF_SIZE);
	74	status = rtas_call(ibm_scan_log_dump, 2, 1, NULL,
	75	(u32) __pa(rtas_data_buf), (u32) count);
	76	memcpy(data, rtas_data_buf, RTAS_DATA_BUF_SIZE);
	77	spin_unlock(&rtas_data_buf_lock);
	78
f7ebf352 ME	79	pr_debug("scanlog: status=%d, data[0]=%x, data[1]=%x, " \
f7ebf352 ME	80	"data[2]=%x\n", status, data[0], data[1], data[2]);
1da177e4 LT	81	switch (status) {
1da177e4 LT	82	case SCANLOG_COMPLETE:
f7ebf352	83	pr_debug("scanlog: hit eof\n");
1da177e4 LT	84	return 0;
1da177e4 LT	85	case SCANLOG_HWERROR:
f7ebf352	86	pr_debug("scanlog: hardware error reading data\n");
1da177e4 LT	87	return -EIO;
	88	case SCANLOG_CONTINUE:
	89	/* We may or may not have data yet */
	90	len = data[1];
	91	off = data[2];
	92	if (len > 0) {
	93	if (copy_to_user(buf, ((char *)data)+off, len))
	94	return -EFAULT;
	95	return len;
	96	}
	97	/* Break to sleep default time */
	98	break;
	99	default:
7932f0b8 JR	100	/* Assume extended busy */
	101	wait_time = rtas_busy_delay_time(status);
	102	if (!wait_time) {
f7ebf352 ME	103	printk(KERN_ERR "scanlog: unknown error " \
f7ebf352 ME	104	"from rtas: %d\n", status);
1da177e4 LT	105	return -EIO;
	106	}
	107	}
	108	/* Apparently no data yet. Wait and try again. */
0287ebed	109	msleep_interruptible(wait_time);
1da177e4 LT	110	}
	111	/NOTREACHED/
	112	}
	113
efa54579	114	static ssize_t scanlog_write(struct file * file, const char __user * buf,
1da177e4 LT	115	size_t count, loff_t *ppos)
	116	{
	117	char stkbuf[20];
	118	int status;
	119
	120	if (count > 19) count = 19;
	121	if (copy_from_user (stkbuf, buf, count)) {
	122	return -EFAULT;
	123	}
	124	stkbuf[count] = 0;
	125
	126	if (buf) {
	127	if (strncmp(stkbuf, "reset", 5) == 0) {
f7ebf352	128	pr_debug("scanlog: reset scanlog\n");
1da177e4	129	status = rtas_call(ibm_scan_log_dump, 2, 1, NULL, 0, 0);
f7ebf352	130	pr_debug("scanlog: rtas returns %d\n", status);
1da177e4 LT	131	}
	132	}
	133	return count;
	134	}
	135
	136	static int scanlog_open(struct inode * inode, struct file * file)
	137	{
	138	struct proc_dir_entry *dp = PDE(inode);
	139	unsigned int data = (unsigned int )dp->data;
	140
1da177e4 LT	141	if (data[0] != 0) {
	142	/* This imperfect test stops a second copy of the
	143	* data (or a reset while data is being copied)
	144	*/
	145	return -EBUSY;
	146	}
	147
	148	data[0] = 0; /* re-init so we restart the scan */
	149
	150	return 0;
	151	}
	152
	153	static int scanlog_release(struct inode * inode, struct file * file)
	154	{
	155	struct proc_dir_entry *dp = PDE(inode);
	156	unsigned int data = (unsigned int )dp->data;
	157
1da177e4 LT	158	data[0] = 0;
	159
	160	return 0;
	161	}
	162
5dfe4c96	163	const struct file_operations scanlog_fops = {
1da177e4 LT	164	.owner = THIS_MODULE,
	165	.read = scanlog_read,
	166	.write = scanlog_write,
	167	.open = scanlog_open,
	168	.release = scanlog_release,
6038f373	169	.llseek = noop_llseek,
1da177e4 LT	170	};
1da177e4 LT	171
8446196a	172	static int __init scanlog_init(void)
1da177e4 LT	173	{
1da177e4 LT	174	struct proc_dir_entry *ent;
f61fb8a5 NL	175	void *data;
f61fb8a5 NL	176	int err = -ENOMEM;
1da177e4 LT	177
1da177e4 LT	178	ibm_scan_log_dump = rtas_token("ibm,scan-log-dump");
f61fb8a5 NL	179	if (ibm_scan_log_dump == RTAS_UNKNOWN_SERVICE)
f61fb8a5 NL	180	return -ENODEV;
1da177e4	181
f61fb8a5 NL	182	/* Ideally we could allocate a buffer < 4G */
	183	data = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
	184	if (!data)
	185	goto err;
	186
188917e1	187	ent = proc_create_data("powerpc/rtas/scan-log-dump", S_IRUSR, NULL,
9185ef67	188	&scanlog_fops, data);
f61fb8a5 NL	189	if (!ent)
	190	goto err;
	191
1da177e4 LT	192	proc_ppc64_scan_log_dump = ent;
	193
	194	return 0;
f61fb8a5 NL	195	err:
	196	kfree(data);
	197	return err;
1da177e4 LT	198	}
1da177e4 LT	199
8446196a	200	static void __exit scanlog_cleanup(void)
1da177e4 LT	201	{
1da177e4 LT	202	if (proc_ppc64_scan_log_dump) {
b2325fe1	203	kfree(proc_ppc64_scan_log_dump->data);
1da177e4 LT	204	remove_proc_entry("scan-log-dump", proc_ppc64_scan_log_dump->parent);
	205	}
	206	}
	207
	208	module_init(scanlog_init);
	209	module_exit(scanlog_cleanup);
	210	MODULE_LICENSE("GPL");