1 files changed, 57 insertions, 0 deletions

diff --git a/drivers/s390/char/sclp_info.c b/drivers/s390/char/sclp_info.c
new file mode 100644
index 000000000000..7bcbe643b087
--- /dev/null
+++ b/drivers/s390/char/sclp_info.c
@@ -0,0 +1,57 @@
+/*
+ *  drivers/s390/char/sclp_info.c
+ *
+ *    Copyright IBM Corp. 2007
+ *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
+ */
+
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <asm/sclp.h>
+#include "sclp.h"
+
+struct sclp_readinfo_sccb s390_readinfo_sccb;
+
+void __init sclp_readinfo_early(void)
+{
+        sclp_cmdw_t command;
+        struct sccb_header *sccb;
+        int ret;
+
+        __ctl_set_bit(0, 9); /* enable service signal subclass mask */
+
+        sccb = &s390_readinfo_sccb.header;
+        command = SCLP_CMDW_READ_SCP_INFO_FORCED;
+        while (1) {
+                u16 response;
+
+                memset(&s390_readinfo_sccb, 0, sizeof(s390_readinfo_sccb));
+                sccb->length = sizeof(s390_readinfo_sccb);
+                sccb->control_mask[2] = 0x80;
+
+                ret = sclp_service_call(command, &s390_readinfo_sccb);
+
+                if (ret == -EIO)
+                        goto out;
+                if (ret == -EBUSY)
+                        continue;
+
+                __load_psw_mask(PSW_BASE_BITS | PSW_MASK_EXT |
+                                PSW_MASK_WAIT | PSW_DEFAULT_KEY);
+                local_irq_disable();
+                barrier();
+
+                response = sccb->response_code;
+
+                if (response == 0x10)
+                        break;
+
+                if (response != 0x1f0 || command == SCLP_CMDW_READ_SCP_INFO)
+                        break;
+
+                command = SCLP_CMDW_READ_SCP_INFO;
+        }
+out:
+        __ctl_clear_bit(0, 9); /* disable service signal subclass mask */
+}