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Diffstat (limited to 'drivers/tty/hvc/hvc_xen.c')
-rw-r--r--drivers/tty/hvc/hvc_xen.c273
1 files changed, 273 insertions, 0 deletions
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
new file mode 100644
index 00000000000..52fdf60bdbe
--- /dev/null
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -0,0 +1,273 @@
+/*
+ * 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 */
+ else
+ irq_set_noprobe(xencons_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);
+}