mmu_example.c File Reference

---

Detailed Description

MMU example application.

This file gives an example of using the MMU to manage the memory on AVR32 MCUs.

• Compiler: IAR EWAAVR32 and GNU GCC for AVR32
• Supported devices: All AVR32 devices with MMU.
• AppNote: AVR32113 Configuration and Use of the Memory Management Unit

Author:

Atmel Corporation: http://www.atmel.com
Support email: avr32@atmel.com

$Name$

Revision

$RCSfile$

Date

Definition in file mmu_example.c.

#include <avr32/io.h>
#include <string.h>
#include <malloc.h>
#include <sys/exceptions.h>
#include "settings.h"
#include "macro.h"
#include "usart.h"
#include "mmu.h"

Include dependency graph for mmu_example.c:

Go to the source code of this file.

Functions
int	main (int argc, char *argv[])
	Main function, program execution starts here.
unsigned int	mmu_exception (int evba_offset, int return_address)
	Exception handler for MMU exceptions.
int	mmuex_exceptions ()
	Use MMU in segmentet mode and with paging to generate a exception.
int	mmuex_segon_pageoff ()
	Use MMU in segmentet mode and without paging.
int	mmuex_segon_pageon ()
	Use MMU in segmentet mode and with paging.
Variables
char	_evba []
	Address to the EVBA which loads functions from handler_table, which is defined by newlib.
static int	free_page_nr = 16
	Start using page 16 and up for exceptions.
static unsigned long	handler_table [0x104]
	handler table for exceptions.
static volatile avr32_pio_t *	pioa = &AVR32_PIOA
	Pointer to PIOA in I/O memory space.
static volatile avr32_pio_t *	piob = &AVR32_PIOB
	Pointer to PIOB in I/O memory space.
static volatile avr32_pio_t *	pioc = &AVR32_PIOC
	Pointer to PIOC in I/O memory space.
static volatile avr32_usart_t *	usart = &USART_MODULE
	Pointer to the USART in I/O memory space.

---

Function Documentation

int main	(	int	argc,
		char *	argv[]
	)

Main function, program execution starts here.

Parameters:

	argc	number of arguments passed on startup
	argv	an array of arguments passed on startup

Definition at line 456 of file mmu_example.c.

References _evba, usart_options_t::baudrate, usart_options_t::channelmode, usart_options_t::charlength, CPUHZ, DELAY_TIMEOUT, handler_table, mmu_exception(), MMU_OK, mmuex_exceptions(), mmuex_segon_pageoff(), mmuex_segon_pageon(), usart_options_t::paritytype, pioa, piob, pioc, usart_options_t::stopbits, usart, USART_1_STOPBIT, USART_BAUD, USART_BITS, usart_linit(), USART_NO_PARITY, USART_NORMAL_CHMODE, and USART_OK.

{
    int error = 0;

    /* set up exceptions */
    init_exceptions((void *)_evba, handler_table);
    _register_exception_handler(&mmu_exception, EVBA_ITLB_MISS);
    _register_exception_handler(&mmu_exception, EVBA_DTLB_MISS_R);
    _register_exception_handler(&mmu_exception, EVBA_DTLB_MISS_W);
    _register_exception_handler(&mmu_exception, EVBA_DTLB_MODIFIED);

    /* disable all interrupts on PIO */
    pioa->idr = 0xFFFFffff;
    piob->idr = 0xFFFFffff;
    pioc->idr = 0xFFFFffff;

    /* Enable USART on PIOA */
    pioa->pdr = AVR32_PIO_P17_MASK|AVR32_PIO_P18_MASK;
    pioa->asr = AVR32_PIO_P17_MASK|AVR32_PIO_P18_MASK;

    /* Enable PIO as debug output/input
     * Output: PC0 => PC15
     * Input : PB0 => PB7
     */
    piob->per = 0x000000FF;
    piob->odr = 0x000000FF;
    piob->ifer = 0x000000FF;
    piob->odsr = 0x00000000;
    piob->puer = 0x000000FF;

    pioc->per = 0x0000FFFF;
    pioc->oer = 0x0000FFFF;
    pioc->ower = 0x0000FFFF;
    pioc->odsr = 0x00000000;

    /* Set options for the USART */
    struct usart_options_t usartOptions;
    usartOptions.baudrate = USART_BAUD;
    usartOptions.charlength = USART_BITS;
    usartOptions.paritytype = USART_NO_PARITY;
    usartOptions.stopbits = USART_1_STOPBIT;
    usartOptions.channelmode = USART_NORMAL_CHMODE;

    /* Initialize USART in RS232 mode */
    error = usart_linit(usart, &usartOptions, CPUHZ);

    if (error != USART_OK) {
        pioc->odsr = AVR32_PIO_P8_MASK|AVR32_PIO_P9_MASK;
        for (;;);
    }

    printf("AVR32113: available demos:\r\n");
    printf("  SW2 - segmentation on\r\n");
    printf("        paging       on\r\n");
    printf("        exception example\r\n\n");
    printf("  SW1 - segmentation on\r\n");
    printf("        paging       on\r\n\n");
    printf("  SW0 - segmentation on\r\n");
    printf("        paging       off\r\n\n");

    unsigned int buttontimer = 0;

    for (;;) {
        /* SW2 - Page miss example
         * SW1 - Segment translation on, page translation on
         * SW0 - Segment translation on, page translation off (default)
         */
        if ((piob->pdsr & AVR32_PIO_P2_MASK) == 0 &&
                buttontimer == 0) {
            pioc->odsr = AVR32_PIO_P2_MASK;
            buttontimer = DELAY_TIMEOUT;

            int retval = MMU_OK;

            retval = mmuex_exceptions();

            if (retval == MMU_OK) {
                pioc->odsr = AVR32_PIO_P10_MASK|AVR32_PIO_P11_MASK;
            } else {
                pioc->odsr = AVR32_PIO_P8_MASK|AVR32_PIO_P9_MASK;
            }
        }
        else if ((piob->pdsr & AVR32_PIO_P1_MASK) == 0 &&
                buttontimer == 0) {
            pioc->odsr = AVR32_PIO_P1_MASK;
            buttontimer = DELAY_TIMEOUT;

            int retval = MMU_OK;

            retval = mmuex_segon_pageon();

            if (retval == MMU_OK) {
                pioc->odsr = AVR32_PIO_P10_MASK|AVR32_PIO_P11_MASK;
            } else {
                pioc->odsr = AVR32_PIO_P8_MASK|AVR32_PIO_P9_MASK;
            }
        }
        else if ((piob->pdsr & AVR32_PIO_P0_MASK) == 0 &&
                buttontimer == 0) {
            pioc->odsr = AVR32_PIO_P0_MASK;
            buttontimer = DELAY_TIMEOUT;

            int retval = MMU_OK;

            retval = mmuex_segon_pageoff();

            if (retval == MMU_OK) {
                pioc->odsr = AVR32_PIO_P10_MASK|AVR32_PIO_P11_MASK;
            } else {
                pioc->odsr = AVR32_PIO_P8_MASK|AVR32_PIO_P9_MASK;
            }
        }

        if (buttontimer > 0) {
            --buttontimer;
        }
    }

    return 0;
}

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unsigned int mmu_exception	(	int	evba_offset,
		int	return_address
	)

Exception handler for MMU exceptions.

Parameters:

	evba_offset	the offset vektor relevant to the EVBA address
	return_address	memory pointer to where the exception handler should return after executing

Definition at line 78 of file mmu_example.c.

References mmu_tlb_t::access, mmu_tlb_t::asid, mmu_tlb_t::bufferable, mmu_tlb_t::cachable, mmu_tlb_t::dirty, free_page_nr, mmu_tlb_t::global, mmu_add_tlb_entry(), MMU_DISABLE, MMU_ENABLE, MMU_OK, MMU_PAGE_SIZE_64KB, mmu_read_bear_and_tlbehi(), MMU_TLB_TYPE_DATA, mmu_tlb_t::page_size, mmu_tlb_t::position, mmu_tlb_t::type, mmu_tlb_t::valid, and mmu_tlb_t::write_through.

Referenced by main().

{
    int retval;
    long bear;
    long vpn;
    long pfn;
    struct mmu_tlb_t tlbOptions;
    tlbOptions.valid = MMU_ENABLE;
    tlbOptions.type = MMU_TLB_TYPE_DATA;
    tlbOptions.asid = 0;
    tlbOptions.cachable = MMU_DISABLE;
    tlbOptions.global = MMU_DISABLE;
    tlbOptions.bufferable = MMU_DISABLE;
    tlbOptions.access = 0x03; /* read/write/execute */
    tlbOptions.page_size = MMU_PAGE_SIZE_64KB;
    tlbOptions.dirty = MMU_ENABLE;
    tlbOptions.write_through = MMU_DISABLE;
    tlbOptions.position = -1;

    printf("\r\n* Handling exception: ");

    switch (evba_offset) {
    case EVBA_ITLB_MISS:
    case EVBA_DTLB_MISS_W:
    case EVBA_DTLB_MISS_R:
        mmu_read_bear_and_tlbehi(&bear, &vpn);
        printf("TLB miss at virtual address 0x%08lx\r\n", bear);
        printf("  Bear is 0x%08lx\r\n", bear);
        printf("  Vpn  is 0x%08lx\r\n", vpn);

        /* Add the page to TLB */
        if (free_page_nr > MMU_DTLB_ENTRIES) {
            free_page_nr = 16;
        }
        tlbOptions.position = free_page_nr++;
        printf("  Adding page to TLB[%02d]...  ", tlbOptions.position);
        /* in SRAM segment */
        if (((bear ^ 0x24000000) >> 24) == 0) {
            pfn = 0x24000000;
        } else {
            pfn = 0;
        }
        retval = mmu_add_tlb_entry(pfn, bear, &tlbOptions);
        if (retval != MMU_OK) {
            printf("[ FAILED ]\r\n");
            goto out;
        }
        printf("[ OK ]\r\n");
        break;
    default:
        printf("unhandled exception 0x%08x!\r\n", evba_offset);
    }

out:
    printf("\n");
    return return_address;
}

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int mmuex_exceptions

(

)

Use MMU in segmentet mode and with paging to generate a exception.

Returns:

Status or error code

Return values:

MMU_OK

on success

Definition at line 142 of file mmu_example.c.

References mmu_tlb_t::access, mmu_tlb_t::asid, mmu_tlb_t::bufferable, mmu_tlb_t::cachable, mmu_tlb_t::dirty, mmu_tlb_t::global, mmu_add_tlb_entry(), MMU_DISABLE, MMU_ENABLE, mmu_init(), MMU_OK, MMU_PAGE_SIZE_64KB, mmu_reset(), MMU_SEGMENTATION_ON, MMU_SHARED_VIRTUAL_MODE, MMU_TLB_TYPE_DATA, mmu_tlb_t::page_size, mmu_tlb_t::position, mmu_tlb_t::type, mmu_tlb_t::valid, and mmu_tlb_t::write_through.

Referenced by main().

{
    int retval = MMU_OK;
    char * string_p = "this test string is used to generate exceptions";
    char * string_p61 = (char *)((long) string_p | 0x61800000);

    printf("\r\nDemonstrate MMU mode...\r\n");
    printf("  Segmentation: ON\r\n");
    printf("  Paging      : ON\r\n");
    printf("  Exceptions  : ON\r\n\n");

    /* Reset MMU */
    printf("  Reset MMU...               ");
    retval = mmu_reset();
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    printf("[ OK ]\r\n");

    /* Set shared mode */
    printf("  Set MMU in shared mode...  ");
    retval = mmu_init(MMU_DISABLE,
            MMU_SHARED_VIRTUAL_MODE,
            MMU_SEGMENTATION_ON);
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    printf("[ OK ]\r\n");

    struct mmu_tlb_t tlbOptions;
    tlbOptions.valid = MMU_ENABLE;
    tlbOptions.type = MMU_TLB_TYPE_DATA;
    tlbOptions.asid = 0;
    tlbOptions.cachable = MMU_DISABLE;
    tlbOptions.global = MMU_DISABLE;
    tlbOptions.bufferable = MMU_DISABLE;
    tlbOptions.access = 0x03; /* read/write/execute */
    tlbOptions.page_size = MMU_PAGE_SIZE_64KB;
    tlbOptions.dirty = MMU_ENABLE;
    tlbOptions.write_through = MMU_DISABLE;
    tlbOptions.position = -1;

    /* Add the segments to TLB */

    /* Inset NOR flash at address 0 */
    printf("  Adding segments to TLB...  ");
    tlbOptions.position = 12;
    retval = mmu_add_tlb_entry(0, 0, &tlbOptions);
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    /* Insert the internal SRAM */
    tlbOptions.position = 14;
    retval = mmu_add_tlb_entry(0x24000000, 0x24000000, &tlbOptions);
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    printf("[ OK ]\r\n");

    /* Change mode */
    printf("  Changing mode...           ");
    retval = mmu_init(MMU_ENABLE,
            MMU_SHARED_VIRTUAL_MODE,
            MMU_SEGMENTATION_ON);
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    printf("[ OK ]\r\n");

    printf("\r\n");
    printf("  String   (0x%08lx): %s\r\n", (long)string_p, string_p);
    /* Use the pointer in the 0x6180xxxx segment without adding the page.
     * This will generate an exception */
    strcpy(string_p61, string_p);

    /* Print out the string which should now be available */
    printf("  String61 (0x%08lx): %s\r\n", (long)string_p61, string_p61);

    printf("\r\n");
    printf("  Test result...             ");

    if (strcmp(string_p, string_p61) == 0) {
        printf("[ OK ]\r\n\n");
    } else {
        printf("[ FAILED ]\r\n\n");
    }

    return retval;
error:
    printf("\r\n");
    printf("  Test result... (jumped)    [ FAILED ]\r\n\n");
    return retval;
}

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int mmuex_segon_pageoff

(

)

Use MMU in segmentet mode and without paging.

Returns:

Status or error code

Return values:

MMU_OK

on success

Definition at line 387 of file mmu_example.c.

References MMU_DISABLE, mmu_init(), MMU_OK, mmu_reset(), MMU_SEGMENTATION_ON, and MMU_SHARED_VIRTUAL_MODE.

Referenced by main().

{
    int retval = MMU_OK;
    char * string_p80 = 0;
    char * string_pA0 = 0;
    char * string_pC0 = 0;
    char * string_p = "MMU test segmentation off, paging on";

    printf("\r\nDemonstrate MMU mode...\r\n");
    printf("  Segmentation: ON\r\n");
    printf("  Paging      : OFF\r\n\n");

    /* Reset MMU */
    printf("  Reset MMU...               ");
    retval = mmu_reset();
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    printf("[ OK ]\r\n");

    /* Change mode */
    printf("  Changing mode...           ");
    retval = mmu_init(MMU_DISABLE,
            MMU_SHARED_VIRTUAL_MODE,
            MMU_SEGMENTATION_ON);
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    printf("[ OK ]\r\n");

    string_p80 = (void*)(0x80000000|(long)string_p);
    string_pA0 = (void*)(0xA0000000|(long)string_p);
    string_pC0 = (void*)(0xC0000000|(long)string_p);

    printf("\r\n");
    printf("  String   (%08x): %s\r\n", (int)string_p, string_p);
    printf("  String80 (%08x): %s\r\n", (int)string_p80, string_p80);
    printf("  StringA0 (%08x): %s\r\n", (int)string_pA0, string_pA0);
    printf("  StringC0 (%08x): %s\r\n", (int)string_pC0, string_pC0);
    printf("\r\n");
    printf("  Test result...             ");

    if (strcmp(string_p, string_p80) == 0 &&
            strcmp(string_p, string_pA0) == 0 &&
            strcmp(string_p, string_pC0) == 0) {
        printf("[ OK ]\r\n\n");
    } else {
        printf("[ FAILED ]\r\n\n");
    }

    return retval;
error:
    printf("\r\n");
    printf("  Test result... (jumped)    [ FAILED ]\r\n\n");
    return retval;
}

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int mmuex_segon_pageon

(

)

Use MMU in segmentet mode and with paging.

Returns:

Status or error code

Return values:

MMU_OK

on success

Definition at line 247 of file mmu_example.c.

References mmu_tlb_t::access, mmu_tlb_t::asid, mmu_tlb_t::bufferable, mmu_tlb_t::cachable, mmu_tlb_t::dirty, mmu_tlb_t::global, mmu_add_tlb_entry(), MMU_DISABLE, MMU_ENABLE, mmu_find_index_to_entry(), mmu_init(), MMU_OK, MMU_PAGE_SIZE_64KB, mmu_reset(), mmu_search_physical_ptr(), mmu_search_virtual_ptr(), MMU_SEGMENTATION_ON, MMU_SHARED_VIRTUAL_MODE, MMU_TLB_TYPE_DATA, mmu_tlb_t::page_size, mmu_tlb_t::position, mmu_tlb_t::type, mmu_tlb_t::valid, and mmu_tlb_t::write_through.

Referenced by main().

{
    int retval = MMU_OK;
    char * string_p = "MMU test segmentation on, paging on";
    long string_p64 = (long) string_p | 0x64080000;
    long string_pPA = 0;
    long string_pVA = 0;

    printf("\r\nDemonstrate MMU mode...\r\n");
    printf("  Segmentation: ON\r\n");
    printf("  Paging      : ON\r\n\n");

    /* Reset MMU */
    printf("  Reset MMU...               ");
    retval = mmu_reset();
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    printf("[ OK ]\r\n");

    /* Set shared mode */
    printf("  Set MMU in shared mode...  ");
    retval = mmu_init(MMU_DISABLE,
            MMU_SHARED_VIRTUAL_MODE,
            MMU_SEGMENTATION_ON);
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    printf("[ OK ]\r\n");

    struct mmu_tlb_t tlbOptions;
    tlbOptions.valid = MMU_ENABLE;
    tlbOptions.type = MMU_TLB_TYPE_DATA;
    tlbOptions.asid = 0;
    tlbOptions.cachable = MMU_DISABLE;
    tlbOptions.global = MMU_DISABLE;
    tlbOptions.bufferable = MMU_DISABLE;
    tlbOptions.access = 0x03; /* read/write/execute */
    tlbOptions.page_size = MMU_PAGE_SIZE_64KB;
    tlbOptions.dirty = MMU_ENABLE;
    tlbOptions.write_through = MMU_DISABLE;
    tlbOptions.position = -1;

    /* Add the segments to TLB */
    printf("  Adding segments to TLB...  ");
    tlbOptions.position = 12;
    retval = mmu_add_tlb_entry(0, 0, &tlbOptions);
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    tlbOptions.position = 14;
    retval = mmu_add_tlb_entry(0x24000000, 0x24000000, &tlbOptions);
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }

    /* Add a memory address which maps to string_p */
    tlbOptions.position = 11;
    retval = mmu_add_tlb_entry((long)string_p, 0x64080000, &tlbOptions);
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    printf("[ OK ]\r\n");

    /* Change mode */
    printf("  Changing mode...           ");
    retval = mmu_init(MMU_ENABLE,
            MMU_SHARED_VIRTUAL_MODE,
            MMU_SEGMENTATION_ON);
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    printf("[ OK ]\r\n");

    /* Search and get the physical
     * address to the pointer
     */
    printf("  Lookup physical address... ");
    retval = mmu_search_virtual_ptr((void *)string_p64, &string_pPA);
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    printf("[ OK ]\r\n");

    /* Search and get the virtual
     * address to the pointer
     */
    printf("  Lookup virtual address...  ");
    retval = mmu_search_physical_ptr((void *)string_pPA, &string_pVA);
    if (retval != MMU_OK) {
        printf("[ FAILED ]\r\n");
        goto error;
    }
    printf("[ OK ]\r\n");

    /* Find the index for the TLB entry */
    long tlbIndex;
    printf("  Get TLB index... ");
    retval = mmu_find_index_to_entry(string_pPA, string_pVA, &tlbIndex);
    if (retval != MMU_OK) {
        printf("          [ FAILED ]\r\n");
        goto error;
    }
    printf("[%02ld]      [ OK ]\r\n", tlbIndex);

    printf("\r\n");
    printf("  String   (0x%08lx): %s\r\n", (long)string_p, string_p);
    printf("  String64 (0x%08lx): %s\r\n", (long)string_p64, (char *)string_p64);
    printf("  StringPA (0x%08lx): %s\r\n", (long)string_pPA, (char *)string_pPA);
    printf("  StringVA (0x%08lx): %s\r\n", (long)string_pVA, (char *)string_pVA);
    printf("\r\n");
    printf("  Test result...             ");

    if (strcmp(string_p, (char *)string_pPA) == 0 &&
            strcmp(string_p, (char *)string_pVA) == 0) {
        printf("[ OK ]\r\n\n");
    } else {
        printf("[ FAILED ]\r\n\n");
    }

    return retval;
error:
    printf("\r\n");
    printf("  Test result... (jumped)    [ FAILED ]\r\n\n");
    return retval;
}

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---

Variable Documentation

char _evba[]

Address to the EVBA which loads functions from handler_table, which is defined by newlib.

Referenced by main().

int free_page_nr = 16 [static]

Start using page 16 and up for exceptions.

Definition at line 60 of file mmu_example.c.

Referenced by mmu_exception().

unsigned long handler_table[0x104] [static]

handler table for exceptions.

Definition at line 70 of file mmu_example.c.

Referenced by main().

volatile avr32_pio_t* pioa = &AVR32_PIOA [static]

Pointer to PIOA in I/O memory space.

Definition at line 62 of file mmu_example.c.

Referenced by main().

volatile avr32_pio_t* piob = &AVR32_PIOB [static]

Pointer to PIOB in I/O memory space.

Definition at line 64 of file mmu_example.c.

Referenced by main().

volatile avr32_pio_t* pioc = &AVR32_PIOC [static]

Pointer to PIOC in I/O memory space.

Definition at line 66 of file mmu_example.c.

Referenced by main().

volatile avr32_usart_t* usart = &USART_MODULE [static]

Pointer to the USART in I/O memory space.

Definition at line 68 of file mmu_example.c.

Referenced by main().

---