S390: ccw firmware: Add sclp output

In order to communicate with the user, we need an I/O mechanism that he
can read. Implement SCLP ASCII support, which happens to be the default
in the s390 ccw machine.

This file is missing read support for now. It can only print messages.

Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 81 insertions, 0 deletions

diff --git a/pc-bios/s390-ccw/sclp-ascii.c b/pc-bios/s390-ccw/sclp-ascii.c
new file mode 100644
index 0000000000..1c93937104
--- /dev/null
+++ b/pc-bios/s390-ccw/sclp-ascii.c
@@ -0,0 +1,81 @@
+/*
+ * SCLP ASCII access driver
+ *
+ * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or (at
+ * your option) any later version. See the COPYING file in the top-level
+ * directory.
+ */
+
+#include "s390-ccw.h"
+#include "sclp.h"
+
+static char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));
+
+/* Perform service call. Return 0 on success, non-zero otherwise. */
+static int sclp_service_call(unsigned int command, void *sccb)
+{
+        int cc;
+
+        asm volatile(
+                "       .insn   rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
+                "       ipm     %0\n"
+                "       srl     %0,28"
+                : "=&d" (cc) : "d" (command), "a" (__pa(sccb))
+                : "cc", "memory");
+        if (cc == 3)
+                return -EIO;
+        if (cc == 2)
+                return -EBUSY;
+        return 0;
+}
+
+static void sclp_set_write_mask(void)
+{
+    WriteEventMask *sccb = (void*)_sccb;
+
+    sccb->h.length = sizeof(WriteEventMask);
+    sccb->mask_length = sizeof(unsigned int);
+    sccb->receive_mask = SCLP_EVENT_MASK_MSG_ASCII;
+    sccb->cp_receive_mask = SCLP_EVENT_MASK_MSG_ASCII;
+    sccb->send_mask = SCLP_EVENT_MASK_MSG_ASCII;
+    sccb->cp_send_mask = SCLP_EVENT_MASK_MSG_ASCII;
+
+    sclp_service_call(SCLP_CMD_WRITE_EVENT_MASK, sccb);
+}
+
+void sclp_setup(void)
+{
+    sclp_set_write_mask();
+}
+
+static int _strlen(const char *str)
+{
+    int i;
+    for (i = 0; *str; i++)
+        str++;
+    return i;
+}
+
+static void _memcpy(char *dest, const char *src, int len)
+{
+    int i;
+    for (i = 0; i < len; i++)
+        dest[i] = src[i];
+}
+
+void sclp_print(const char *str)
+{
+    int len = _strlen(str);
+    WriteEventData *sccb = (void*)_sccb;
+
+    sccb->h.length = sizeof(WriteEventData) + len;
+    sccb->h.function_code = SCLP_FC_NORMAL_WRITE;
+    sccb->ebh.length = sizeof(EventBufferHeader) + len;
+    sccb->ebh.type = SCLP_EVENT_ASCII_CONSOLE_DATA;
+    sccb->ebh.flags = 0;
+    _memcpy(sccb->data, str, len);
+
+    sclp_service_call(SCLP_CMD_WRITE_EVENT_DATA, sccb);
+}