diff options
Diffstat (limited to 'drivers/char/hvc_xen.c')
| -rw-r--r-- | drivers/char/hvc_xen.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/drivers/char/hvc_xen.c b/drivers/char/hvc_xen.c new file mode 100644 index 00000000000..dd68f8541c2 --- /dev/null +++ b/drivers/char/hvc_xen.c @@ -0,0 +1,159 @@ +/* + * 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/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 inline struct xencons_interface *xencons_interface(void) +{ + return mfn_to_virt(xen_start_info->console.domU.mfn); +} + +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(uint32_t vtermno, 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; + + notify_daemon(); + return sent; +} + +static int 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 hvc_ops = { + .get_chars = read_console, + .put_chars = write_console, +}; + +static int __init xen_init(void) +{ + struct hvc_struct *hp; + + if (!is_running_on_xen()) + return 0; + + 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, &hvc_ops, 256); + if (IS_ERR(hp)) + return PTR_ERR(hp); + + hvc = hp; + return 0; +} + +static void __exit xen_fini(void) +{ + if (hvc) + hvc_remove(hvc); +} + +static int xen_cons_init(void) +{ + if (!is_running_on_xen()) + return 0; + + hvc_instantiate(HVC_COOKIE, 0, &hvc_ops); + return 0; +} + +module_init(xen_init); +module_exit(xen_fini); +console_initcall(xen_cons_init); + +static void xenboot_write_console(struct console *console, const char *string, + unsigned len) +{ + unsigned int linelen, off = 0; + const char *pos; + + while (off < len && NULL != (pos = strchr(string+off, '\n'))) { + linelen = pos-string+off; + if (off + linelen > len) + break; + write_console(0, string+off, linelen); + write_console(0, "\r\n", 2); + off += linelen + 1; + } + if (off < len) + write_console(0, string+off, len-off); +} + +struct console xenboot_console = { + .name = "xenboot", + .write = xenboot_write_console, + .flags = CON_PRINTBUFFER | CON_BOOT, +}; |