/*
* test_sdram.c
* ------------
* Test code for the 2x512 MBit SDRAM working memory.
*
* Copyright (c) 2016, NORDUnet A/S 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.
*
* - Neither the name of the NORDUnet nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT
* HOLDER OR CONTRIBUTORS 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.
*/
#include "stm-led.h"
#include "stm-sdram.h"
#include "test_sdram.h"
uint32_t lfsr1;
uint32_t lfsr2;
int test_sdram_sequential(uint32_t *base_addr)
{
// memory offset
int offset;
// readback value
uint32_t sdram_readback;
/* This test fills entire memory chip with some pseudo-random pattern
starting from the very first cell and going in linear fashion. It then
reads entire memory and compares read values with what was written. */
// turn on yellow led to indicate, that we're writing
led_on(LED_YELLOW);
//
// Note, that SDRAM_SIZE is in BYTES, and since we write using
// 32-bit words, total number of words is SDRAM_SIZE / 4.
//
// fill entire memory with "random" values
for (offset=0; offset<(SDRAM_SIZE >> 2); offset++) {
// generate next "random" value to write
lfsr1 = lfsr_next_32(lfsr1);
// write to memory
base_addr[offset] = lfsr1;
}
// turn off yellow led to indicate, that we're going to read
led_off(LED_YELLOW);
// read entire memory and compare values
for (offset=0; offset<(SDRAM_SIZE >> 2); offset++) {
// generate next "random" value (we use the second LFSR to catch up)
lfsr2 = lfsr_next_32(lfsr2);
// read from memory
sdram_readback = base_addr[offset];
// compare and abort test in case of mismatch
if (sdram_readback != lfsr2) return 0;
}
// done
return 1;
}
//-----------------------------------------------------------------------------
int test_sdram_random(uint32_t *base_addr)
//-----------------------------------------------------------------------------
{
// cell counter, memory offset
int counter, offset;
// readback value
uint32_t sdram_readback;
/* This test fills entire memory chip with some pseudo-random pattern
starting from the very first cell, but then jumping around in pseudo-
random fashion to make sure, that SDRAM controller in STM32 handles
bank, row and column switching correctly. It then reads entire memory
and compares read values with what was written. */
// turn on yellow led to indicate, that we're writing
led_on(LED_YELLOW);
//
// Note, that SDRAM_SIZE is in BYTES, and since we write using
// 32-bit words, total number of words is SDRAM_SIZE / 4.
//
// start with the first cell
for (counter=0, offset=0; counter<(SDRAM_SIZE >> 2); counter++) {
// generate next "random" value to write
lfsr1 = lfsr_next_32(lfsr1);
// write to memory
base_addr[offset] = lfsr1;
// generate next "random" address
//
// Note, that for 64 MB memory with 32-bit data bus we need 24 bits
// of address, so we use 24-bit LFSR here. Since LFSR has only 2^^24-1
// states, i.e. all possible 24-bit values excluding 0, we have to
// manually kick it into some arbitrary state during the first iteration.
//
offset = offset ? lfsr_next_24(offset) : 0x00DEC0DE;
}
// turn off yellow led to indicate, that we're going to read
led_off(LED_YELLOW);
// read entire memory and compare values
for (counter=0, offset=0; counter<(SDRAM_SIZE >> 2); counter++) {
// generate next "random" value (we use the second LFSR to catch up)
lfsr2 = lfsr_next_32(lfsr2);
// read from memory
sdram_readback = base_addr[offset];
// compare and abort test in case of mismatch
if (sdram_readback != lfsr2) return 0;
// generate next "random" address
offset = offset ? lfsr_next_24(offset) : 0x00DEC0DE;
}
//
// we should have walked exactly 2**24 iterations and returned
// back to the arbitrary starting address...
//
if (offset != 0x00DEC0DE) return 0;
// done
return 1;
}
//-----------------------------------------------------------------------------
int test_sdrams_interleaved(uint32_t *base_addr1, uint32_t *base_addr2)
//-----------------------------------------------------------------------------
{
// cell counter, memory offsets
int counter, offset1, offset2;
// readback value
uint32_t sdram_readback;
/* Basically this is the same as test_sdram_random() except that it
tests both memory chips at the same time. */
// turn on yellow led to indicate, that we're writing
led_on(LED_YELLOW);
//
// Note, that SDRAM_SIZE is in BYTES, and since we write using
// 32-bit words, total number of words is SDRAM_SIZE / 4.
//
// start with the first cell
for (counter=0, offset1=0, offset2=0; counter<(SDRAM_SIZE >> 2); counter++) {
// generate next "random" value to write
lfsr1 = lfsr_next_32(lfsr1);
// write to memory
base_addr1[offset1] = lfsr1;
base_addr2[offset2] = lfsr1;
// generate next "random" addresses (use different starting states!)
offset1 = offset1 ? lfsr_next_24(offset1) : 0x00ABCDEF;
offset2 = offset2 ? lfsr_next_24(offset2) : 0x00FEDCBA;
}
// turn off yellow led to indicate, that we're going to read
led_off(LED_YELLOW);
// read entire memory and compare values
for (counter=0, offset1=0, offset2=0; counter<(SDRAM_SIZE >> 2); counter++) {
// generate next "random" value (we use the second LFSR to catch up)
lfsr2 = lfsr_next_32(lfsr2);
// read from the first memory and compare
sdram_readback = base_addr1[offset1];
if (sdram_readback != lfsr2) return 0;
// read from the second memory and compare
sdram_readback = base_addr2[offset2];
if (sdram_readback != lfsr2) return 0;
// generate next "random" addresses
offset1 = offset1 ? lfsr_next_24(offset1) : 0x00ABCDEF;
offset2 = offset2 ? lfsr_next_24(offset2) : 0x00FEDCBA;
}
//
// we should have walked exactly 2**24 iterations and returned
// back to the arbitrary starting address...
//
if (offset1 != 0x00ABCDEF) return 0;
if (offset2 != 0x00FEDCBA) return 0;
// done
return 1;
}
uint32_t lfsr_next_32(uint32_t lfsr)
{
uint32_t tap = 0;
tap ^= (lfsr >> 31);
tap ^= (lfsr >> 30);
tap ^= (lfsr >> 29);
tap ^= (lfsr >> 9);
return (lfsr << 1) | (tap & 1);
}
uint32_t lfsr_next_24(uint32_t lfsr)
{
unsigned int tap = 0;
tap ^= (lfsr >> 23);
tap ^= (lfsr >> 22);
tap ^= (lfsr >> 21);
tap ^= (lfsr >> 16);
return ((lfsr << 1) | (tap & 1)) & 0x00FFFFFF;
}
