/*
 * Copyright (c) 2008 Pavel Rimsky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup kernel_sparc64
 * @{
 */
/**
 * @file
 * @brief Niagara input/output driver based on hypervisor calls.
 */

#include <arch/drivers/niagara.h>
#include <console/chardev.h>
#include <console/console.h>
#include <ddi/ddi.h>
#include <arch/asm.h>
#include <arch.h>
#include <stdlib.h>
#include <arch/drivers/niagara_buf.h>
#include <arch/drivers/kbd.h>
#include <arch/sun4v/hypercall.h>
#include <sysinfo/sysinfo.h>
#include <ipc/irq.h>
#include <proc/thread.h>
#include <console/console.h>
#include <genarch/srln/srln.h>

/* Polling interval in miliseconds */
#define POLL_INTERVAL  10000

/* Device instance */
static niagara_instance_t *instance = NULL;

static void niagara_write(outdev_t *, const char *, size_t);

/** Character device operations */
static outdev_operations_t niagara_ops = {
	.write = niagara_write,
	.redraw = NULL,
	.scroll_up = NULL,
	.scroll_down = NULL
};

/**
 * The driver uses hypercalls to print characters to the console. Since the
 * hypercall cannot be performed from the userspace, we do this:
 *
 * The kernel "little brother" driver (which will be present no matter what
 * the DDI architecture is -- as we need the kernel part for the kconsole)
 * defines a shared buffer. Kernel walks through the buffer (in the same thread
 * which is used for polling the keyboard) and prints any pending characters
 * to the console (using hypercalls).
 *
 * The userspace fb server maps this shared buffer to its address space and
 * output operation it does is performed using the mapped buffer. The shared
 * buffer definition follows.
 */
static volatile niagara_output_buffer_t __attribute__((aligned(PAGE_SIZE)))
    output_buffer;

static parea_t outbuf_parea;

/**
 * Analogous to the output_buffer, see the previous definition.
 */
static volatile niagara_input_buffer_t __attribute__((aligned(PAGE_SIZE)))
    input_buffer;

static parea_t inbuf_parea;

/** Write a single character to the standard output. */
static inline void do_putchar(uint8_t c)
{
	/* Repeat until the buffer is non-full */
	while (__hypercall_fast1(CONS_PUTCHAR, c) == HV_EWOULDBLOCK)
		;
}

static void niagara_write(outdev_t *dev, const char *s, size_t n)
{
	/* If the userspace owns the console, do not output anything. */
	if (outbuf_parea.mapped && !console_override)
		return;

	const char *top = s + n;
	assert(top >= s);

	for (; s < top; s++) {
		if (*s == '\n')
			do_putchar('\r');

		do_putchar((uint8_t) *s);
	}
}

/** Poll keyboard and print pending characters.
 *
 * Ask the hypervisor whether there is any unread character. If so,
 * pick it up and send it to the indev layer.
 *
 * Check whether the userspace output driver has pushed any
 * characters to the output buffer and eventually print them.
 *
 */
static void niagara_poll(void)
{
	/*
	 * Print any pending characters from the
	 * shared buffer to the console.
	 */

	while (output_buffer.read_ptr != output_buffer.write_ptr) {
		do_putchar(output_buffer.data[output_buffer.read_ptr]);
		output_buffer.read_ptr =
		    ((output_buffer.read_ptr) + 1) % OUTPUT_BUFFER_SIZE;
	}

	/*
	 * Read character from keyboard.
	 */

	uint64_t c;
	if (__hypercall_fast_ret1(0, 0, 0, 0, 0, CONS_GETCHAR, &c) == HV_EOK) {
		if ((!inbuf_parea.mapped) || (console_override)) {
			/*
			 * Kernel console is active, send
			 * the character to kernel.
			 */
			indev_push_character(instance->srlnin, c);
		} else {
			/*
			 * Kernel console is inactive, send
			 * the character to uspace driver.
			 */
			input_buffer.data[input_buffer.write_ptr] = (char) c;
			input_buffer.write_ptr =
			    ((input_buffer.write_ptr) + 1) % INPUT_BUFFER_SIZE;
		}
	}
}

/** Polling thread function.
 *
 */
static void kniagarapoll(void *arg)
{
	while (true) {
		niagara_poll();
		thread_usleep(POLL_INTERVAL);
	}
}

/** Initialize the input/output subsystem
 *
 */
static void niagara_init(void)
{
	if (instance)
		return;

	instance = malloc(sizeof(niagara_instance_t));
	instance->thread = thread_create(kniagarapoll, NULL, TASK,
	    THREAD_FLAG_UNCOUNTED, "kniagarapoll");

	if (!instance->thread) {
		free(instance);
		instance = NULL;
		return;
	}

	instance->srlnin = NULL;

	output_buffer.read_ptr = 0;
	output_buffer.write_ptr = 0;
	input_buffer.write_ptr = 0;
	input_buffer.read_ptr = 0;

	/*
	 * Set sysinfos and pareas so that the userspace counterpart of the
	 * niagara fb and kbd driver can communicate with kernel using shared
	 * buffers.
	 */

	sysinfo_set_item_val("fb", NULL, true);
	sysinfo_set_item_val("fb.kind", NULL, 5);

	sysinfo_set_item_val("niagara.outbuf.address", NULL,
	    KA2PA(&output_buffer));
	sysinfo_set_item_val("niagara.outbuf.size", NULL,
	    PAGE_SIZE);
	sysinfo_set_item_val("niagara.outbuf.datasize", NULL,
	    OUTPUT_BUFFER_SIZE);

	sysinfo_set_item_val("niagara.inbuf.address", NULL,
	    KA2PA(&input_buffer));
	sysinfo_set_item_val("niagara.inbuf.size", NULL,
	    PAGE_SIZE);
	sysinfo_set_item_val("niagara.inbuf.datasize", NULL,
	    INPUT_BUFFER_SIZE);

	ddi_parea_init(&outbuf_parea);
	outbuf_parea.pbase = (uintptr_t) (KA2PA(&output_buffer));
	outbuf_parea.frames = 1;
	outbuf_parea.unpriv = false;
	outbuf_parea.mapped = false;
	ddi_parea_register(&outbuf_parea);

	inbuf_parea.pbase = (uintptr_t) (KA2PA(&input_buffer));
	inbuf_parea.frames = 1;
	inbuf_parea.unpriv = false;
	inbuf_parea.mapped = false;
	ddi_parea_register(&inbuf_parea);

	outdev_t *niagara_dev = malloc(sizeof(outdev_t));
	outdev_initialize("niagara_dev", niagara_dev, &niagara_ops);
	stdout_wire(niagara_dev);
}

/** Initialize input from the Niagara console.
 *
 */
niagara_instance_t *niagarain_init(void)
{
	niagara_init();

	if (instance) {
		srln_instance_t *srln_instance = srln_init();
		if (srln_instance) {
			indev_t *sink = stdin_wire();
			indev_t *srln = srln_wire(srln_instance, sink);

			instance->srlnin = srln;
			thread_start(instance->thread);
		}
	}

	return instance;
}

/** @}
 */