MIPS: Add code for new system 'paravirt'

For para-virtualized guests running under KVM or other equivalent
hypervisor.

Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7004/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 40 insertions, 0 deletions

diff --git a/arch/mips/paravirt/serial.c b/arch/mips/paravirt/serial.c
new file mode 100644
index 000000000000..02b665c02272
--- /dev/null
+++ b/arch/mips/paravirt/serial.c
@@ -0,0 +1,40 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2013 Cavium, Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/virtio_console.h>
+#include <linux/kvm_para.h>
+
+/*
+ * Emit one character to the boot console.
+ */
+int prom_putchar(char c)
+{
+	kvm_hypercall3(KVM_HC_MIPS_CONSOLE_OUTPUT, 0 /*  port 0 */,
+		(unsigned long)&c, 1 /* len == 1 */);
+
+	return 1;
+}
+
+#ifdef CONFIG_VIRTIO_CONSOLE
+static int paravirt_put_chars(u32 vtermno, const char *buf, int count)
+{
+	kvm_hypercall3(KVM_HC_MIPS_CONSOLE_OUTPUT, vtermno,
+		(unsigned long)buf, count);
+
+	return count;
+}
+
+static int __init paravirt_cons_init(void)
+{
+	virtio_cons_early_init(paravirt_put_chars);
+	return 0;
+}
+core_initcall(paravirt_cons_init);
+
+#endif