1 files changed, 235 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/scanlog.c b/arch/powerpc/platforms/pseries/scanlog.c
new file mode 100644
index 000000000000..2edc947f7c44
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/scanlog.c
@@ -0,0 +1,235 @@
+/*
+ *  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/ppc64/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 <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
+
+#define DEBUG(A...) do { if (scanlog_debug) printk(KERN_ERR "scanlog: " A); } while (0)
+
+static int scanlog_debug;
+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 inode * inode = file->f_dentry->d_inode;
+        struct proc_dir_entry *dp;
+        unsigned int *data;
+        int status;
+        unsigned long len, off;
+        unsigned int wait_time;
+
+        dp = PDE(inode);
+        data = (unsigned int *)dp->data;
+
+        if (!data) {
+                printk(KERN_ERR "scanlog: read failed no data\n");
+                return -EIO;
+        }
+
+        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);
+
+                DEBUG("status=%d, data[0]=%x, data[1]=%x, data[2]=%x\n",
+                      status, data[0], data[1], data[2]);
+                switch (status) {
+                    case SCANLOG_COMPLETE:
+                        DEBUG("hit eof\n");
+                        return 0;
+                    case SCANLOG_HWERROR:
+                        DEBUG("hardware error reading scan log 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:
+                        if (status > 9900 && status <= 9905) {
+                                wait_time = rtas_extended_busy_delay_time(status);
+                        } else {
+                                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) {
+                        DEBUG("reset scanlog\n");
+                        status = rtas_call(ibm_scan_log_dump, 2, 1, NULL, 0, 0);
+                        DEBUG("rtas returns %d\n", status);
+                } else if (strncmp(stkbuf, "debugon", 7) == 0) {
+                        printk(KERN_ERR "scanlog: debug on\n");
+                        scanlog_debug = 1;
+                } else if (strncmp(stkbuf, "debugoff", 8) == 0) {
+                        printk(KERN_ERR "scanlog: debug off\n");
+                        scanlog_debug = 0;
+                }
+        }
+        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) {
+                printk(KERN_ERR "scanlog: open failed no data\n");
+                return -EIO;
+        }
+
+        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;
+
+        if (!data) {
+                printk(KERN_ERR "scanlog: release failed no data\n");
+                return -EIO;
+        }
+        data[0] = 0;
+
+        return 0;
+}
+
+struct file_operations scanlog_fops = {
+        .owner          = THIS_MODULE,
+        .read           = scanlog_read,
+        .write          = scanlog_write,
+        .open           = scanlog_open,
+        .release        = scanlog_release,
+};
+
+int __init scanlog_init(void)
+{
+        struct proc_dir_entry *ent;
+
+        ibm_scan_log_dump = rtas_token("ibm,scan-log-dump");
+        if (ibm_scan_log_dump == RTAS_UNKNOWN_SERVICE) {
+                printk(KERN_ERR "scan-log-dump not implemented on this system\n");
+                return -EIO;
+        }
+
+        ent = create_proc_entry("ppc64/rtas/scan-log-dump",  S_IRUSR, NULL);
+        if (ent) {
+                ent->proc_fops = &scanlog_fops;
+                /* Ideally we could allocate a buffer < 4G */
+                ent->data = kmalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
+                if (!ent->data) {
+                        printk(KERN_ERR "Failed to allocate a buffer\n");
+                        remove_proc_entry("scan-log-dump", ent->parent);
+                        return -ENOMEM;
+                }
+                ((unsigned int *)ent->data)[0] = 0;
+        } else {
+                printk(KERN_ERR "Failed to create ppc64/scan-log-dump proc entry\n");
+                return -EIO;
+        }
+        proc_ppc64_scan_log_dump = ent;
+
+        return 0;
+}
+
+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");