s390/sclp: Add SCLP character device driver
Add a character misc device "sclp_ctl" that allows to run SCCBs
from user space using the SCLP_CTL_SCCB ioctl.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/char/sclp_ctl.c b/drivers/s390/char/sclp_ctl.c
new file mode 100644
index 0000000..abe8ef1
--- /dev/null
+++ b/drivers/s390/char/sclp_ctl.c
@@ -0,0 +1,145 @@
+/*
+ * IOCTL interface for SCLP
+ *
+ * Copyright IBM Corp. 2012
+ *
+ * Author: Michael Holzheu <holzheu@linux.vnet.ibm.com>
+ */
+
+#include <linux/compat.h>
+#include <linux/uaccess.h>
+#include <linux/miscdevice.h>
+#include <linux/gfp.h>
+#include <linux/module.h>
+#include <linux/ioctl.h>
+#include <linux/fs.h>
+#include <linux/compat.h>
+#include <asm/compat.h>
+#include <asm/sclp_ctl.h>
+#include <asm/sclp.h>
+
+#include "sclp.h"
+
+/*
+ * Supported command words
+ */
+static unsigned int sclp_ctl_sccb_wlist[] = {
+ 0x00400002,
+ 0x00410002,
+};
+
+/*
+ * Check if command word is supported
+ */
+static int sclp_ctl_cmdw_supported(unsigned int cmdw)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(sclp_ctl_sccb_wlist); i++) {
+ if (cmdw == sclp_ctl_sccb_wlist[i])
+ return 1;
+ }
+ return 0;
+}
+
+static void __user *u64_to_uptr(u64 value)
+{
+ if (is_compat_task())
+ return compat_ptr(value);
+ else
+ return (void __user *)(unsigned long)value;
+}
+
+/*
+ * Start SCLP request
+ */
+static int sclp_ctl_ioctl_sccb(void __user *user_area)
+{
+ struct sclp_ctl_sccb ctl_sccb;
+ struct sccb_header *sccb;
+ int rc;
+
+ if (copy_from_user(&ctl_sccb, user_area, sizeof(ctl_sccb)))
+ return -EFAULT;
+ if (!sclp_ctl_cmdw_supported(ctl_sccb.cmdw))
+ return -EOPNOTSUPP;
+ sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
+ if (!sccb)
+ return -ENOMEM;
+ if (copy_from_user(sccb, u64_to_uptr(ctl_sccb.sccb), sizeof(*sccb))) {
+ rc = -EFAULT;
+ goto out_free;
+ }
+ if (sccb->length > PAGE_SIZE || sccb->length < 8)
+ return -EINVAL;
+ if (copy_from_user(sccb, u64_to_uptr(ctl_sccb.sccb), sccb->length)) {
+ rc = -EFAULT;
+ goto out_free;
+ }
+ rc = sclp_sync_request(ctl_sccb.cmdw, sccb);
+ if (rc)
+ goto out_free;
+ if (copy_to_user(u64_to_uptr(ctl_sccb.sccb), sccb, sccb->length))
+ rc = -EFAULT;
+out_free:
+ free_page((unsigned long) sccb);
+ return rc;
+}
+
+/*
+ * SCLP SCCB ioctl function
+ */
+static long sclp_ctl_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *argp;
+
+ if (is_compat_task())
+ argp = compat_ptr(arg);
+ else
+ argp = (void __user *) arg;
+ switch (cmd) {
+ case SCLP_CTL_SCCB:
+ return sclp_ctl_ioctl_sccb(argp);
+ default: /* unknown ioctl number */
+ return -ENOTTY;
+ }
+}
+
+/*
+ * File operations
+ */
+static const struct file_operations sclp_ctl_fops = {
+ .owner = THIS_MODULE,
+ .open = nonseekable_open,
+ .unlocked_ioctl = sclp_ctl_ioctl,
+ .compat_ioctl = sclp_ctl_ioctl,
+ .llseek = no_llseek,
+};
+
+/*
+ * Misc device definition
+ */
+static struct miscdevice sclp_ctl_device = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "sclp",
+ .fops = &sclp_ctl_fops,
+};
+
+/*
+ * Register sclp_ctl misc device
+ */
+static int __init sclp_ctl_init(void)
+{
+ return misc_register(&sclp_ctl_device);
+}
+module_init(sclp_ctl_init);
+
+/*
+ * Deregister sclp_ctl misc device
+ */
+static void __exit sclp_ctl_exit(void)
+{
+ misc_deregister(&sclp_ctl_device);
+}
+module_exit(sclp_ctl_exit);