/*
 * 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 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 <ddi/device.h>
#include <arch/asm.h>
#include <arch/drivers/kbd.h>
#include <arch/sun4v/hypercall.h>
#include <sysinfo/sysinfo.h>
#include <ipc/irq.h>

/**
 * The driver is polling based, but in order to notify the userspace
 * of a key being pressed, we need to supply the interface with some
 * interrupt number. The interrupt number can be arbitrary as it it
 * will never be used for identifying HW interrupts, but only in
 * notifying the userspace. 
 */
#define FICTIONAL_INR		1

/* functions referenced from definitions of I/O operations structures */
static void niagara_putchar(chardev_t *, const char);
static void niagara_noop(chardev_t *);
static char niagara_read(chardev_t *);

/** character device operations */
static chardev_operations_t niagara_ops = {
	.write = niagara_putchar,
	.suspend = niagara_noop,
	.resume = niagara_noop,
	.read = niagara_read
};

/*
 * 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.
 */
#define OUTPUT_BUFFER_SIZE	((PAGE_SIZE) - 2 * 8)
static volatile struct {
	uint64_t read_ptr;
	uint64_t write_ptr;
	char data[OUTPUT_BUFFER_SIZE];
}
	__attribute__ ((packed))
	__attribute__ ((aligned(PAGE_SIZE)))
	output_buffer;

/** Niagara character device */
chardev_t niagara_io;

/**
 * Niagara IRQ structure. So far used only for notifying the userspace of the
 * key being pressed, not for kernel being informed about keyboard interrupts.
 */ 
static irq_t niagara_irq;

/** defined in drivers/kbd.c */
extern kbd_type_t kbd_type;

/**
 * The character read will be stored here until the (notified) uspace
 * driver picks it up.
 */
static char read_char;

/**
 * The driver works in polled mode, so no interrupt should be handled by it.
 */
static irq_ownership_t niagara_claim(void)
{
	return IRQ_DECLINE;
}

/**
 * The driver works in polled mode, so no interrupt should be handled by it.
 */
static void niagara_irq_handler(irq_t *irq, void *arg, ...)
{
	panic("Not yet implemented, SGCN works in polled mode.\n");
}

/** Writes a single character to the standard output. */
static inline void do_putchar(const char c) {
	/* repeat until the buffer is non-full */
	while (__hypercall_fast1(CONS_PUTCHAR, c) == EWOULDBLOCK)
		;
}

/** Writes a single character to the standard output. */
static void niagara_putchar(struct chardev * cd, const char c)
{
	do_putchar(c);
	if (c == '\n')
		do_putchar('\r');
}

/**
 * Grabs the input for kernel.
 */
void niagara_grab(void)
{
	ipl_t ipl = interrupts_disable();
	spinlock_lock(&niagara_irq.lock);
	niagara_irq.notif_cfg.notify = false;
	spinlock_unlock(&niagara_irq.lock);
	interrupts_restore(ipl);
}

/**
 * Releases the input so that userspace can use it.
 */
void niagara_release(void)
{
	ipl_t ipl = interrupts_disable();
	spinlock_lock(&niagara_irq.lock);
	if (niagara_irq.notif_cfg.answerbox)
		niagara_irq.notif_cfg.notify = true;
	spinlock_unlock(&niagara_irq.lock);
	interrupts_restore(ipl);
}

/**
 * Default suspend/resume operation for the input device.
 */
static void niagara_noop(chardev_t *d)
{
}

/**
 * Called when actively reading the character.
 */
static char niagara_read(chardev_t *d)
{
	uint64_t c;

	if (__hypercall_fast_ret1(0, 0, 0, 0, 0, CONS_GETCHAR, &c) == EOK) {
		return (char) c;
	}

	return '\0';
}

/**
 * Returns the character last read. This function is called from the
 * pseudocode - the character returned by this function is passed to
 * the userspace keyboard driver.
 */
char niagara_getc(void) {
	return read_char;
}

/**
 * Function regularly called by the keyboard polling thread. Asks the
 * hypervisor whether there is any unread character. If so, it picks it up
 * and sends it to the upper layers of HelenOS.
 */
void niagara_poll(void)
{
	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;
	}

	uint64_t c;

	if (__hypercall_fast_ret1(0, 0, 0, 0, 0, CONS_GETCHAR, &c) == EOK) {
		ipl_t ipl = interrupts_disable();
		spinlock_lock(&niagara_irq.lock);

		if (niagara_irq.notif_cfg.notify &&
				niagara_irq.notif_cfg.answerbox) {
			/*
			 * remember the character, uspace will pick it
			 * up using pseudocode
			 */
			read_char = (char) c;
			ipc_irq_send_notif(&niagara_irq);
			spinlock_unlock(&niagara_irq.lock);
			interrupts_restore(ipl);
			return;
		} else {
			spinlock_unlock(&niagara_irq.lock);
			interrupts_restore(ipl);	

			chardev_push_character(&niagara_io, c);	
			if (c == '\r')
				chardev_push_character(&niagara_io, '\n');
		}
	}

}

/**
 * Initializes the input/output subsystem so that the Niagara standard
 * input/output is used.
 */
void niagara_init(void)
{
	kbd_type = KBD_SUN4V;

	devno_t devno = device_assign_devno();
	irq_initialize(&niagara_irq);
	niagara_irq.devno = devno;
	niagara_irq.inr = FICTIONAL_INR;
	niagara_irq.claim = niagara_claim;
	niagara_irq.handler = niagara_irq_handler;
	irq_register(&niagara_irq);
	
	sysinfo_set_item_val("kbd", NULL, true);
	sysinfo_set_item_val("kbd.type", NULL, KBD_SUN4V);
	sysinfo_set_item_val("kbd.devno", NULL, devno);
	sysinfo_set_item_val("kbd.inr", NULL, FICTIONAL_INR);
	sysinfo_set_item_val("fb.kind", NULL, 5);

	/*
	 * Set sysinfos and pareas so that the userspace counterpart of the
	 * niagara fb driver can communicate with kernel using a shared buffer.
 	 */
	output_buffer.read_ptr = 0;
	output_buffer.write_ptr = 0;
	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);
	static parea_t outbuf_parea;
	outbuf_parea.pbase = (uintptr_t) (KA2PA(&output_buffer));
	outbuf_parea.vbase = (uintptr_t) (&output_buffer);
	outbuf_parea.frames = 1;
	outbuf_parea.cacheable = false;
	ddi_parea_register(&outbuf_parea);

	chardev_initialize("niagara_io", &niagara_io, &niagara_ops);
	stdin = &niagara_io;
	stdout = &niagara_io;
}

/** @}
 */