source: mainline/kernel/arch/arm32/src/drivers/gxemul.c@ 9446f39

/*
 * Copyright (c) 2007 Michal Kebrt, Petr Stepan
 * 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 arm32gxemul
 * @{
 */
/** @file
 *  @brief GXemul drivers.
 */

#include <interrupt.h>
#include <ipc/irq.h>
#include <console/chardev.h>
#include <arch/drivers/gxemul.h>
#include <console/console.h>
#include <sysinfo/sysinfo.h>
#include <print.h>
#include <ddi/device.h>
#include <mm/page.h>
#include <arch/machine.h>
#include <arch/debug/print.h>

/* Addresses of devices. */
#define GXEMUL_VIDEORAM            0x10000000
#define GXEMUL_KBD                 0x10000000
#define GXEMUL_HALT_OFFSET         0x10
#define GXEMUL_RTC                 0x15000000
#define GXEMUL_RTC_FREQ_OFFSET     0x100
#define GXEMUL_RTC_ACK_OFFSET      0x110
#define GXEMUL_IRQC                0x16000000
#define GXEMUL_IRQC_MASK_OFFSET    0x4
#define GXEMUL_IRQC_UNMASK_OFFSET  0x8
#define GXEMUL_MP                  0x11000000
#define GXEMUL_MP_MEMSIZE_OFFSET   0x0090
#define GXEMUL_FB                  0x12000000

/* IRQs */
#define GXEMUL_KBD_IRQ          2
#define GXEMUL_TIMER_IRQ        4

static gxemul_hw_map_t gxemul_hw_map;
static chardev_t console;
static irq_t gxemul_console_irq;
static irq_t gxemul_timer_irq;

static bool hw_map_init_called = false;

static void gxemul_kbd_enable(chardev_t *dev);
static void gxemul_kbd_disable(chardev_t *dev);
static void gxemul_write(chardev_t *dev, const char ch, bool silent);
static char gxemul_do_read(chardev_t *dev);

static chardev_operations_t gxemul_ops = {
        .resume = gxemul_kbd_enable,
        .suspend = gxemul_kbd_disable,
        .write = gxemul_write,
        .read = gxemul_do_read,
};


/** Returns the mask of active interrupts. */
static inline uint32_t gxemul_irqc_get_sources(void)
{
        return *((uint32_t *) gxemul_hw_map.irqc);
}


/** Masks interrupt.
 * 
 * @param irq interrupt number
 */
static inline void gxemul_irqc_mask(uint32_t irq)
{
        *((uint32_t *) gxemul_hw_map.irqc_mask) = irq;
}


/** Unmasks interrupt.
 * 
 * @param irq interrupt number
 */
static inline void gxemul_irqc_unmask(uint32_t irq)
{
        *((uint32_t *) gxemul_hw_map.irqc_unmask) = irq;
}


/** Initializes #gxemul_hw_map. */
void gxemul_hw_map_init(void)
{
        gxemul_hw_map.videoram = hw_map(GXEMUL_VIDEORAM, PAGE_SIZE);
        gxemul_hw_map.kbd = hw_map(GXEMUL_KBD, PAGE_SIZE);
        gxemul_hw_map.rtc = hw_map(GXEMUL_RTC, PAGE_SIZE);
        gxemul_hw_map.irqc = hw_map(GXEMUL_IRQC, PAGE_SIZE);

        gxemul_hw_map.rtc_freq = gxemul_hw_map.rtc + GXEMUL_RTC_FREQ_OFFSET;
        gxemul_hw_map.rtc_ack = gxemul_hw_map.rtc + GXEMUL_RTC_ACK_OFFSET;
        gxemul_hw_map.irqc_mask = gxemul_hw_map.irqc + GXEMUL_IRQC_MASK_OFFSET;
        gxemul_hw_map.irqc_unmask = gxemul_hw_map.irqc +
            GXEMUL_IRQC_UNMASK_OFFSET;

        hw_map_init_called = true;
}


/** Putchar that works with gxemul. 
 *
 * @param dev Not used.
 * @param ch Characted to be printed.
 */
static void gxemul_write(chardev_t *dev, const char ch, bool silent)
{
        if (!silent)
                *((char *) gxemul_hw_map.videoram) = ch;
}

/** Enables gxemul keyboard (interrupt unmasked).
 *
 * @param dev Not used.
 *
 * Called from getc(). 
 */
static void gxemul_kbd_enable(chardev_t *dev)
{
        gxemul_irqc_unmask(GXEMUL_KBD_IRQ);
}

/** Disables gxemul keyboard (interrupt masked).
 *
 * @param dev not used
 *
 * Called from getc().
 */
static void gxemul_kbd_disable(chardev_t *dev)
{
        gxemul_irqc_mask(GXEMUL_KBD_IRQ);
}

/** Read character using polling, assume interrupts disabled.
 *
 *  @param dev Not used.
 */
static char gxemul_do_read(chardev_t *dev)
{
        char ch;

        while (1) {
                ch = *((volatile char *) gxemul_hw_map.kbd);
                if (ch) {
                        if (ch == '\r')
                                return '\n';
                        if (ch == 0x7f)
                                return '\b';
                        return ch;
                }
        }
}

/** Process keyboard interrupt. 
 *  
 *  @param irq IRQ information.
 */
static void gxemul_irq_handler(irq_t *irq)
{
        char ch = 0;
                
        ch = *((char *) gxemul_hw_map.kbd);
        if (ch == '\r') {
                ch = '\n';
        }
        if (ch == 0x7f) {
                ch = '\b';
        }
        chardev_push_character(&console, ch);
}

static irq_ownership_t gxemul_claim(irq_t *irq)
{
        return IRQ_ACCEPT;
}


/** Acquire console back for kernel. */
void gxemul_grab_console(void)
{
        ipl_t ipl = interrupts_disable();
        spinlock_lock(&gxemul_console_irq.lock);
        gxemul_console_irq.notif_cfg.notify = false;
        spinlock_unlock(&gxemul_console_irq.lock);
        interrupts_restore(ipl);
}

/** Return console to userspace. */
void gxemul_release_console(void)
{
        ipl_t ipl = interrupts_disable();
        spinlock_lock(&gxemul_console_irq.lock);
        if (gxemul_console_irq.notif_cfg.answerbox) {
                gxemul_console_irq.notif_cfg.notify = true;
        }
        spinlock_unlock(&gxemul_console_irq.lock);
        interrupts_restore(ipl);
}

/** Initializes console object representing gxemul console.
 *
 *  @param devno device number.
 */
void gxemul_console_init(devno_t devno)
{
        chardev_initialize("gxemul_console", &console, &gxemul_ops);
        stdin = &console;
        stdout = &console;
        
        irq_initialize(&gxemul_console_irq);
        gxemul_console_irq.devno = devno;
        gxemul_console_irq.inr = GXEMUL_KBD_IRQ;
        gxemul_console_irq.claim = gxemul_claim;
        gxemul_console_irq.handler = gxemul_irq_handler;
        irq_register(&gxemul_console_irq);
        
        gxemul_irqc_unmask(GXEMUL_KBD_IRQ);
        
        sysinfo_set_item_val("kbd", NULL, true);
        sysinfo_set_item_val("kbd.devno", NULL, devno);
        sysinfo_set_item_val("kbd.inr", NULL, GXEMUL_KBD_IRQ);
        sysinfo_set_item_val("kbd.address.virtual", NULL, gxemul_hw_map.kbd);
}

/** Starts gxemul Real Time Clock device, which asserts regular interrupts.
 * 
 * @param frequency Interrupts frequency (0 disables RTC).
 */
static void gxemul_timer_start(uint32_t frequency)
{
        *((uint32_t*) gxemul_hw_map.rtc_freq) = frequency;
}

static irq_ownership_t gxemul_timer_claim(irq_t *irq)
{
        return IRQ_ACCEPT;
}

/** Timer interrupt handler.
 *
 * @param irq Interrupt information.
 * @param arg Not used.
 */
static void gxemul_timer_irq_handler(irq_t *irq)
{
        /*
        * We are holding a lock which prevents preemption.
        * Release the lock, call clock() and reacquire the lock again.
        */
        spinlock_unlock(&irq->lock);
        clock();
        spinlock_lock(&irq->lock);

        /* acknowledge tick */
        *((uint32_t*) gxemul_hw_map.rtc_ack) = 0;
}

/** Initializes and registers timer interrupt handler. */
static void gxemul_timer_irq_init(void)
{
        irq_initialize(&gxemul_timer_irq);
        gxemul_timer_irq.devno = device_assign_devno();
        gxemul_timer_irq.inr = GXEMUL_TIMER_IRQ;
        gxemul_timer_irq.claim = gxemul_timer_claim;
        gxemul_timer_irq.handler = gxemul_timer_irq_handler;

        irq_register(&gxemul_timer_irq);
}


/** Starts timer.
 *
 * Initiates regular timer interrupts after initializing
 * corresponding interrupt handler.
 */
void gxemul_timer_irq_start(void)
{
        gxemul_timer_irq_init();
        gxemul_timer_start(GXEMUL_TIMER_FREQ);
}

/** Returns the size of emulated memory.
 *
 * @return Size in bytes.
 */
size_t gxemul_get_memory_size(void) 
{
        return  *((int *) (GXEMUL_MP + GXEMUL_MP_MEMSIZE_OFFSET));
}

/** Prints a character. 
 *
 *  @param ch Character to be printed.
 */
void gxemul_debug_putc(char ch)
{
        char *addr = 0;
        if (!hw_map_init_called) {
                addr = (char *) GXEMUL_KBD;
        } else {
                addr = (char *) gxemul_hw_map.videoram;
        }

        *(addr) = ch;
}

/** Stops gxemul. */
void gxemul_cpu_halt(void)
{
        char * addr = 0;
        if (!hw_map_init_called) {
                addr = (char *) GXEMUL_KBD;
        } else {
                addr = (char *) gxemul_hw_map.videoram;
        }
        
        *(addr + GXEMUL_HALT_OFFSET) = '\0';
}

/** Gxemul specific interrupt exception handler.
 *
 * Determines sources of the interrupt from interrupt controller and
 * calls high-level handlers for them.
 *
 * @param exc_no Interrupt exception number.
 * @param istate Saved processor state.
 */
void gxemul_irq_exception(int exc_no, istate_t *istate)
{
        uint32_t sources = gxemul_irqc_get_sources();
        int i;
        
        for (i = 0; i < GXEMUL_IRQC_MAX_IRQ; i++) {
                if (sources & (1 << i)) {
                        irq_t *irq = irq_dispatch_and_lock(i);
                        if (irq) {
                                /* The IRQ handler was found. */
                                irq->handler(irq);
                                spinlock_unlock(&irq->lock);
                        } else {
                                /* Spurious interrupt.*/
                                dprintf("cpu%d: spurious interrupt (inum=%d)\n",
                                    CPU->id, i);
                        }
                }
        }
}

/** Returns address of framebuffer device.
 *
 *  @return Address of framebuffer device.
 */
uintptr_t gxemul_get_fb_address(void)
{
        return (uintptr_t) GXEMUL_FB;
}

/** @}
 */