/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/types.h>

#include <sys/hypervisor.h>
#include <sys/machparam.h>
#include <xen/public/io/console.h>
#include <sys/mach_mmu.h>

shared_info_t *HYPERVISOR_shared_info;
void *HYPERVISOR_console_page;

#if defined(_BOOT)
#include "dboot/dboot_printf.h"
char big_empty[MMU_PAGESIZE * 3];	/* room for 2 page aligned page */
#endif /* _BOOT */

unsigned short video_fb_buf[32 * 1024 + MMU_PAGESIZE];
unsigned char kb_status_buf[MMU_PAGESIZE * 2];
unsigned short *video_fb = NULL;
unsigned char *kb_status = NULL;

static volatile struct xencons_interface *cons_ifp;

#define	XR_FULL(r)	((r)->xr_in_cnt - (r)->xr_out_cnt == XR_SIZE)
#define	XR_EMPTY(r)	((r)->xr_in_cnt == (r)->xr_out_cnt)

#define	PTE_BITS	(PT_VALID | PT_WRITABLE)
#define	PTE_DEV_BITS	(PT_VALID | PT_WRITABLE | PT_NOCACHE | PT_NOCONSIST | \
			PT_FOREIGN)

/*
 * For some unfortunate reason, the hypervisor doesn't bother to include the
 * shared info in the original virtual address space.  This means we can't
 * do any console I/O until we have manipulated some pagetables. So we have to
 * do this bit of code with no ability to get debug output.
 */
/*ARGSUSED*/
void
bcons_init_xen(char *cmdline)
{
#ifdef _BOOT
	int i = 0;
	uintptr_t vaddr;

	/*
	 * find a page aligned virtual address in "big_empty"
	 */
	vaddr = (uintptr_t)&big_empty;
	vaddr = (vaddr + MMU_PAGEOFFSET) & MMU_PAGEMASK;
	HYPERVISOR_shared_info = (shared_info_t *)vaddr;

	/*
	 * Sets the "present" and "writable" bits in the PTE
	 * plus user for amd64.
	 */
	(void) HYPERVISOR_update_va_mapping(vaddr,
	    xen_info->shared_info | PTE_BITS, UVMF_INVLPG | UVMF_LOCAL);

	if (!DOMAIN_IS_INITDOMAIN(xen_info)) {
		/*
		 * map the xen console ring buffers
		 */
		(void) HYPERVISOR_update_va_mapping(vaddr + MMU_PAGESIZE,
		    mmu_ptob((x86pte_t)xen_info->console.domU.mfn) | PTE_BITS,
		    UVMF_INVLPG | UVMF_LOCAL);
	} else {
		/*
		 * Xen will pass dom0 information about the current
		 * display settings via xen_info->console.dom0.  This
		 * information includes what video mode we're in (vga
		 * or vesa) and some basic information about the video
		 * mode.  (screen size, cursor location, etc.)  We're
		 * just going to ignore all this info.  Here's some
		 * reasons why:
		 *
		 * - Currently Solaris itself has no support for vesa.
		 *   Also, the only way to boot Solaris is using our
		 *   patched version of grub, which conveniently doesn't
		 *   support vesa either.
		 *
		 * - By default when solaris boots up it clears the screen
		 *   thereby removing any previously displayed grub/xen
		 *   console messages, so we really don't care about the
		 *   current vga settings.
		 *
		 * Initially we'll map device memory for the frame buffer
		 * and keyboard into some local memory that already has
		 * page table entries so that we can get very basic debug
		 * output.  Later on when we're initializing page tables
		 * we'll map re-map these devices to be at their expected
		 * addresses.  Note that these mappings created below will
		 * be torn down right before the kernel boots up when
		 * all the memory and mappings associated with dboot are
		 * released.
		 *
		 * Map the frame buffer.
		 */
		vaddr = (uintptr_t)&video_fb_buf;
		vaddr = (vaddr + MMU_PAGEOFFSET) & MMU_PAGEMASK;
		for (i = 0; i < 32 * 1024; i += MMU_PAGESIZE)
			(void) HYPERVISOR_update_va_mapping(vaddr + i,
			    0xb8000 + i | PTE_DEV_BITS,
			    UVMF_INVLPG | UVMF_LOCAL);
		video_fb = (unsigned short *)vaddr;

		/* Map the keyboard */
		vaddr = (uintptr_t)&kb_status_buf;
		vaddr = (vaddr + MMU_PAGEOFFSET) & MMU_PAGEMASK;
		(void) HYPERVISOR_update_va_mapping(vaddr, 0x0 | PTE_DEV_BITS,
		    UVMF_INVLPG | UVMF_LOCAL);
		kb_status = (unsigned char *)vaddr;
	}

#endif /* _BOOT */
	if (!DOMAIN_IS_INITDOMAIN(xen_info)) {
		HYPERVISOR_console_page =
		    (void *)((uintptr_t)HYPERVISOR_shared_info + MMU_PAGESIZE);
	} else {
		HYPERVISOR_console_page = NULL;
	}
}


/*
 * This is the equivalent of polled I/O across the hypervisor CONSOLE
 * channel to output 1 character at a time.
 */
void
bcons_putchar_xen(int c)
{
	evtchn_send_t send;
	char buffer = (char)c;

	if (DOMAIN_IS_INITDOMAIN(xen_info)) {
		(void) HYPERVISOR_console_io(CONSOLEIO_write, 1, &buffer);
		return;
	}

	cons_ifp = (volatile struct xencons_interface *)HYPERVISOR_console_page;

	/*
	 * need to add carriage return for new lines
	 */
	if (c == '\n')
		bcons_putchar_xen('\r');

	/*
	 * We have to wait till we have an open transmit slot.
	 */
	while (cons_ifp->out_prod - cons_ifp->out_cons >=
	    sizeof (cons_ifp->out))
		(void) HYPERVISOR_yield();

	cons_ifp->out[MASK_XENCONS_IDX(cons_ifp->out_prod, cons_ifp->out)] =
	    (char)c;
	++cons_ifp->out_prod;

	/*
	 * Signal Domain 0 that it has something to do for us.
	 */
	send.port = xen_info->console.domU.evtchn;
	(void) HYPERVISOR_event_channel_op(EVTCHNOP_send, &send);
}

static uint_t have_char = 0;
static char buffered;

/*
 * See if there is a character on input.
 */
int
bcons_ischar_xen(void)
{
	if (DOMAIN_IS_INITDOMAIN(xen_info)) {
		if (have_char)
			return (1);
		if (HYPERVISOR_console_io(CONSOLEIO_read, 1, &buffered) > 0)
			return (have_char = 1);
		return (0);
	}

	cons_ifp = (volatile struct xencons_interface *)HYPERVISOR_console_page;
	if (cons_ifp->in_cons == cons_ifp->in_prod)
		return (0);
	return (1);
}

/*
 * get a console input character
 */
int
bcons_getchar_xen(void)
{
	evtchn_send_t send;
	char c;

	if (DOMAIN_IS_INITDOMAIN(xen_info)) {
		while (have_char == 0)
			(void) bcons_ischar_xen();
		have_char = 0;
		return (buffered);
	}

	cons_ifp = (volatile struct xencons_interface *)HYPERVISOR_console_page;
	while (cons_ifp->in_cons == cons_ifp->in_prod)
		(void) HYPERVISOR_yield();

	c = cons_ifp->in[MASK_XENCONS_IDX(cons_ifp->in_cons, cons_ifp->in)];
	++cons_ifp->in_cons;

	/*
	 * Signal Domain 0 that we ate a character.
	 */
	send.port = xen_info->console.domU.evtchn;
	(void) HYPERVISOR_event_channel_op(EVTCHNOP_send, &send);
	return (c);
}