--- /dev/null
+/*
+ * 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 unsigned int *scanlog_buffer; /* The data buffer */
+
+static ssize_t scanlog_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ unsigned int *data = scanlog_buffer;
+ 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)
+{
+ unsigned int *data = scanlog_buffer;
+
+ 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)
+{
+ unsigned int *data = scanlog_buffer;
+
+ 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;
+ 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 */
+ scanlog_buffer = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
+ if (!scanlog_buffer)
+ goto err;
+
+ ent = proc_create("powerpc/rtas/scan-log-dump", S_IRUSR, NULL,
+ &scanlog_fops);
+ if (!ent)
+ goto err;
+ return 0;
+err:
+ kfree(scanlog_buffer);
+ return err;
+}
+
+static void __exit scanlog_cleanup(void)
+{
+ remove_proc_entry("powerpc/rtas/scan-log-dump", NULL);
+ kfree(scanlog_buffer);
+}
+
+module_init(scanlog_init);
+module_exit(scanlog_cleanup);
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff