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/*

 * Copyright (c) 2005 Jakub Jermar

 * 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 mips32mm   

 * @{

 */

/** @file

 */

#include <macros.h>

#include <arch/mm/frame.h>

#include <arch/mm/tlb.h>

#include <interrupt.h>

#include <mm/frame.h>

#include <mm/asid.h>

#include <config.h>

#include <arch/drivers/msim.h>

#include <arch/drivers/serial.h>

#include <print.h>

#define ZERO_PAGE_MASK      TLB_PAGE_MASK_256K

#define ZERO_FRAMES         16384

#define ZERO_PAGE_WIDTH     18  /* 256K */

#define ZERO_PAGE_SIZE      (1 << ZERO_PAGE_WIDTH)

#define ZERO_PAGE_ASID      ASID_INVALID

#define ZERO_PAGE_TLBI      0

#define ZERO_PAGE_ADDR      0

#define ZERO_PAGE_OFFSET    (ZERO_PAGE_SIZE / sizeof(uint32_t) - 1)

#define ZERO_PAGE_VALUE     (((volatile uint32_t *) ZERO_PAGE_ADDR)[ZERO_PAGE_OFFSET])

#define MAX_REGIONS         32

typedef struct {

    pfn_t start;

    pfn_t count;

} phys_region_t;

static count_t phys_regions_count = 0;

static phys_region_t phys_regions[MAX_REGIONS];

/** Check whether frame is available

 *

 * Returns true if given frame is generally available for use.

 * Returns false if given frame is used for physical memory

 * mapped devices and cannot be used.

 *

 */

static bool frame_available(pfn_t frame)

{

    /* MSIM device (dprinter) */

    if (frame == (KA2PA(MSIM_VIDEORAM) >> ZERO_PAGE_WIDTH))

        return false;

    /* MSIM device (dkeyboard) */

    if (frame == (KA2PA(MSIM_KBD_ADDRESS) >> ZERO_PAGE_WIDTH))

        return false;

    /* Simics device (serial line) */

    if (frame == (KA2PA(SERIAL_ADDRESS) >> ZERO_PAGE_WIDTH))

        return false;

    return true;

}

/** Check whether frame is safe to write

 *

 * Returns true if given frame is safe for read/write test.

 * Returns false if given frame should not be touched.

 *

 */

static bool frame_safe(pfn_t frame)

{

    /* Kernel structures */

    if ((frame << ZERO_PAGE_WIDTH) < KA2PA(config.base))

        return false;

    /* Kernel */

    if (overlaps(frame << ZERO_PAGE_WIDTH, ZERO_PAGE_SIZE,

        KA2PA(config.base), config.kernel_size))

        return false;

    /* Kernel stack */

    if (overlaps(frame << ZERO_PAGE_WIDTH, ZERO_PAGE_SIZE,

        KA2PA(config.stack_base), config.stack_size))

        return false;

    /* Init tasks */

    bool safe = true;

    count_t i;

    for (i = 0; i < init.cnt; i++)

        if (overlaps(frame << ZERO_PAGE_WIDTH, ZERO_PAGE_SIZE,

            KA2PA(init.tasks[i].addr), init.tasks[i].size)) {

            safe = false;

            break;

        }

    return safe;

}

static void frame_add_region(pfn_t start_frame, pfn_t end_frame)

{

    if (end_frame > start_frame) {

        /* Convert 1M frames to 16K frames */

        pfn_t first = ADDR2PFN(start_frame << ZERO_PAGE_WIDTH);

        pfn_t count = ADDR2PFN((end_frame - start_frame) << ZERO_PAGE_WIDTH);

        /* Interrupt vector frame is blacklisted */

        pfn_t conf_frame;

        if (first == 0)

            conf_frame = 1;

        else

            conf_frame = first;

        zone_create(first, count, conf_frame, 0);

        if (phys_regions_count < MAX_REGIONS) {

            phys_regions[phys_regions_count].start = first;

            phys_regions[phys_regions_count].count = count;

            phys_regions_count++;

        }

    }

}

/** Create memory zones

 *

 * Walk through available 256 KB chunks of physical

 * memory and create zones.

 *

 * Note: It is assumed that the TLB is not yet being

 * used in any way, thus there is no interference.

 *

 */

void frame_arch_init(void)

{

    ipl_t ipl = interrupts_disable();

    /* Clear and initialize TLB */

    cp0_pagemask_write(ZERO_PAGE_MASK);

    cp0_entry_lo0_write(0);

    cp0_entry_lo1_write(0);

    cp0_entry_hi_write(0);

    count_t i;

    for (i = 0; i < TLB_ENTRY_COUNT; i++) {

        cp0_index_write(i);

        tlbwi();

    }

    pfn_t start_frame = 0;

    pfn_t frame;

    bool avail = true;

    /* Walk through all 1 MB frames */

    for (frame = 0; frame < ZERO_FRAMES; frame++) {

        if (!frame_available(frame))

            avail = false;

        else {

            if (frame_safe(frame)) {

                entry_lo_t lo0;

                entry_lo_t lo1;

                entry_hi_t hi;

                tlb_prepare_entry_lo(&lo0, false, true, true, false, frame << (ZERO_PAGE_WIDTH - 12));

                tlb_prepare_entry_lo(&lo1, false, false, false, false, 0);

                tlb_prepare_entry_hi(&hi, ZERO_PAGE_ASID, ZERO_PAGE_ADDR);

                cp0_pagemask_write(ZERO_PAGE_MASK);

                cp0_entry_lo0_write(lo0.value);

                cp0_entry_lo1_write(lo1.value);

                cp0_entry_hi_write(hi.value);

                cp0_index_write(ZERO_PAGE_TLBI);

                tlbwi();

                ZERO_PAGE_VALUE = 0;

                if (ZERO_PAGE_VALUE != 0)

                    avail = false;

                else {

                    ZERO_PAGE_VALUE = 0xdeadbeef;

                    if (ZERO_PAGE_VALUE != 0xdeadbeef)

                        avail = false;

                }

            }

        }

        if (!avail) {

            frame_add_region(start_frame, frame);

            start_frame = frame + 1;

            avail = true;

        }

    }

    frame_add_region(start_frame, frame);

    /* Blacklist interrupt vector frame */

    frame_mark_unavailable(0, 1);

    /* Cleanup */

    cp0_pagemask_write(ZERO_PAGE_MASK);

    cp0_entry_lo0_write(0);

    cp0_entry_lo1_write(0);

    cp0_entry_hi_write(0);

    cp0_index_write(ZERO_PAGE_TLBI);

    tlbwi();

    interrupts_restore(ipl);

}

void physmem_print(void)

{

    printf("Base       Size\n");

    printf("---------- ----------\n");

    count_t i;

    for (i = 0; i < phys_regions_count; i++) {

        printf("%#010x %10u\n",

            PFN2ADDR(phys_regions[i].start), PFN2ADDR(phys_regions[i].count));

    }  

}

/** @}

 */