1 files changed, 271 insertions, 0 deletions

diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
new file mode 100644
index 000000000000..3740e327f180
--- /dev/null
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -0,0 +1,271 @@
+/*
+ * xen console driver interface to hvc_console.c
+ *
+ * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
+ *
+ * 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/console.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/types.h>
+
+#include <asm/xen/hypervisor.h>
+
+#include <xen/xen.h>
+#include <xen/page.h>
+#include <xen/events.h>
+#include <xen/interface/io/console.h>
+#include <xen/hvc-console.h>
+
+#include "hvc_console.h"
+
+#define HVC_COOKIE   0x58656e /* "Xen" in hex */
+
+static struct hvc_struct *hvc;
+static int xencons_irq;
+
+/* ------------------------------------------------------------------ */
+
+static unsigned long console_pfn = ~0ul;
+
+static inline struct xencons_interface *xencons_interface(void)
+{
+        if (console_pfn == ~0ul)
+                return mfn_to_virt(xen_start_info->console.domU.mfn);
+        else
+                return __va(console_pfn << PAGE_SHIFT);
+}
+
+static inline void notify_daemon(void)
+{
+        /* Use evtchn: this is called early, before irq is set up. */
+        notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
+}
+
+static int __write_console(const char *data, int len)
+{
+        struct xencons_interface *intf = xencons_interface();
+        XENCONS_RING_IDX cons, prod;
+        int sent = 0;
+
+        cons = intf->out_cons;
+        prod = intf->out_prod;
+        mb();                   /* update queue values before going on */
+        BUG_ON((prod - cons) > sizeof(intf->out));
+
+        while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
+                intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
+
+        wmb();                  /* write ring before updating pointer */
+        intf->out_prod = prod;
+
+        if (sent)
+                notify_daemon();
+        return sent;
+}
+
+static int domU_write_console(uint32_t vtermno, const char *data, int len)
+{
+        int ret = len;
+
+        /*
+         * Make sure the whole buffer is emitted, polling if
+         * necessary.  We don't ever want to rely on the hvc daemon
+         * because the most interesting console output is when the
+         * kernel is crippled.
+         */
+        while (len) {
+                int sent = __write_console(data, len);
+                
+                data += sent;
+                len -= sent;
+
+                if (unlikely(len))
+                        HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
+        }
+
+        return ret;
+}
+
+static int domU_read_console(uint32_t vtermno, char *buf, int len)
+{
+        struct xencons_interface *intf = xencons_interface();
+        XENCONS_RING_IDX cons, prod;
+        int recv = 0;
+
+        cons = intf->in_cons;
+        prod = intf->in_prod;
+        mb();                   /* get pointers before reading ring */
+        BUG_ON((prod - cons) > sizeof(intf->in));
+
+        while (cons != prod && recv < len)
+                buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
+
+        mb();                   /* read ring before consuming */
+        intf->in_cons = cons;
+
+        notify_daemon();
+        return recv;
+}
+
+static struct hv_ops domU_hvc_ops = {
+        .get_chars = domU_read_console,
+        .put_chars = domU_write_console,
+        .notifier_add = notifier_add_irq,
+        .notifier_del = notifier_del_irq,
+        .notifier_hangup = notifier_hangup_irq,
+};
+
+static int dom0_read_console(uint32_t vtermno, char *buf, int len)
+{
+        return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
+}
+
+/*
+ * Either for a dom0 to write to the system console, or a domU with a
+ * debug version of Xen
+ */
+static int dom0_write_console(uint32_t vtermno, const char *str, int len)
+{
+        int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
+        if (rc < 0)
+                return 0;
+
+        return len;
+}
+
+static struct hv_ops dom0_hvc_ops = {
+        .get_chars = dom0_read_console,
+        .put_chars = dom0_write_console,
+        .notifier_add = notifier_add_irq,
+        .notifier_del = notifier_del_irq,
+        .notifier_hangup = notifier_hangup_irq,
+};
+
+static int __init xen_hvc_init(void)
+{
+        struct hvc_struct *hp;
+        struct hv_ops *ops;
+
+        if (!xen_pv_domain())
+                return -ENODEV;
+
+        if (xen_initial_domain()) {
+                ops = &dom0_hvc_ops;
+                xencons_irq = bind_virq_to_irq(VIRQ_CONSOLE, 0);
+        } else {
+                if (!xen_start_info->console.domU.evtchn)
+                        return -ENODEV;
+
+                ops = &domU_hvc_ops;
+                xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
+        }
+        if (xencons_irq < 0)
+                xencons_irq = 0; /* NO_IRQ */
+
+        hp = hvc_alloc(HVC_COOKIE, xencons_irq, ops, 256);
+        if (IS_ERR(hp))
+                return PTR_ERR(hp);
+
+        hvc = hp;
+
+        console_pfn = mfn_to_pfn(xen_start_info->console.domU.mfn);
+
+        return 0;
+}
+
+void xen_console_resume(void)
+{
+        if (xencons_irq)
+                rebind_evtchn_irq(xen_start_info->console.domU.evtchn, xencons_irq);
+}
+
+static void __exit xen_hvc_fini(void)
+{
+        if (hvc)
+                hvc_remove(hvc);
+}
+
+static int xen_cons_init(void)
+{
+        struct hv_ops *ops;
+
+        if (!xen_pv_domain())
+                return 0;
+
+        if (xen_initial_domain())
+                ops = &dom0_hvc_ops;
+        else
+                ops = &domU_hvc_ops;
+
+        hvc_instantiate(HVC_COOKIE, 0, ops);
+        return 0;
+}
+
+module_init(xen_hvc_init);
+module_exit(xen_hvc_fini);
+console_initcall(xen_cons_init);
+
+#ifdef CONFIG_EARLY_PRINTK
+static void xenboot_write_console(struct console *console, const char *string,
+                                  unsigned len)
+{
+        unsigned int linelen, off = 0;
+        const char *pos;
+
+        dom0_write_console(0, string, len);
+
+        if (xen_initial_domain())
+                return;
+
+        domU_write_console(0, "(early) ", 8);
+        while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
+                linelen = pos-string+off;
+                if (off + linelen > len)
+                        break;
+                domU_write_console(0, string+off, linelen);
+                domU_write_console(0, "\r\n", 2);
+                off += linelen + 1;
+        }
+        if (off < len)
+                domU_write_console(0, string+off, len-off);
+}
+
+struct console xenboot_console = {
+        .name           = "xenboot",
+        .write          = xenboot_write_console,
+        .flags          = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
+};
+#endif  /* CONFIG_EARLY_PRINTK */
+
+void xen_raw_console_write(const char *str)
+{
+        dom0_write_console(0, str, strlen(str));
+}
+
+void xen_raw_printk(const char *fmt, ...)
+{
+        static char buf[512];
+        va_list ap;
+
+        va_start(ap, fmt);
+        vsnprintf(buf, sizeof(buf), fmt, ap);
+        va_end(ap);
+
+        xen_raw_console_write(buf);
+}