lguest: the console driver

A simple console driver for lguest.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 103 insertions, 0 deletions

diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 8852b8d643cf..4e6f387fd189 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -42,6 +42,7 @@ obj-$(CONFIG_SYNCLINK_GT)	+= synclink_gt.o
 obj-$(CONFIG_N_HDLC)            += n_hdlc.o
 obj-$(CONFIG_AMIGA_BUILTIN_SERIAL) += amiserial.o
 obj-$(CONFIG_SX)                += sx.o generic_serial.o
+obj-$(CONFIG_LGUEST_GUEST)      += hvc_lguest.o
 obj-$(CONFIG_RIO)               += rio/ generic_serial.o
 obj-$(CONFIG_HVC_CONSOLE)       += hvc_vio.o hvsi.o
 obj-$(CONFIG_HVC_ISERIES)       += hvc_iseries.o
diff --git a/drivers/char/hvc_lguest.c b/drivers/char/hvc_lguest.c
new file mode 100644
index 000000000000..e7b889e404a7
--- /dev/null
+++ b/drivers/char/hvc_lguest.c
@@ -0,0 +1,102 @@
+/* Simple console for lguest.
+ *
+ * Copyright (C) 2006 Rusty Russell, IBM Corporation
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/lguest_bus.h>
+#include "hvc_console.h"
+
+static char inbuf[256];
+static struct lguest_dma cons_input = { .used_len = 0,
+                                        .addr[0] = __pa(inbuf),
+                                        .len[0] = sizeof(inbuf),
+                                        .len[1] = 0 };
+
+static int put_chars(u32 vtermno, const char *buf, int count)
+{
+        struct lguest_dma dma;
+
+        /* FIXME: what if it's over a page boundary? */
+        dma.len[0] = count;
+        dma.len[1] = 0;
+        dma.addr[0] = __pa(buf);
+
+        lguest_send_dma(LGUEST_CONSOLE_DMA_KEY, &dma);
+        return count;
+}
+
+static int get_chars(u32 vtermno, char *buf, int count)
+{
+        static int cons_offset;
+
+        if (!cons_input.used_len)
+                return 0;
+
+        if (cons_input.used_len - cons_offset < count)
+                count = cons_input.used_len - cons_offset;
+
+        memcpy(buf, inbuf + cons_offset, count);
+        cons_offset += count;
+        if (cons_offset == cons_input.used_len) {
+                cons_offset = 0;
+                cons_input.used_len = 0;
+        }
+        return count;
+}
+
+static struct hv_ops lguest_cons = {
+        .get_chars = get_chars,
+        .put_chars = put_chars,
+};
+
+static int __init cons_init(void)
+{
+        if (strcmp(paravirt_ops.name, "lguest") != 0)
+                return 0;
+
+        return hvc_instantiate(0, 0, &lguest_cons);
+}
+console_initcall(cons_init);
+
+static int lguestcons_probe(struct lguest_device *lgdev)
+{
+        int err;
+
+        lgdev->private = hvc_alloc(0, lgdev_irq(lgdev), &lguest_cons, 256);
+        if (IS_ERR(lgdev->private))
+                return PTR_ERR(lgdev->private);
+
+        err = lguest_bind_dma(LGUEST_CONSOLE_DMA_KEY, &cons_input, 1,
+                              lgdev_irq(lgdev));
+        if (err)
+                printk("lguest console: failed to bind buffer.\n");
+        return err;
+}
+
+static struct lguest_driver lguestcons_drv = {
+        .name = "lguestcons",
+        .owner = THIS_MODULE,
+        .device_type = LGUEST_DEVICE_T_CONSOLE,
+        .probe = lguestcons_probe,
+};
+
+static int __init hvc_lguest_init(void)
+{
+        return register_lguest_driver(&lguestcons_drv);
+}
+module_init(hvc_lguest_init);