/**
* \brief Test the address bus
*
* Tests the address bus for stuck and coupled lines.
*
* The bytes at base and all power-of-two locations are initialized with the
* value 0x55 before any testing of the address bus is done.
*
* The first test of the address bus is for lines that are stuck high. This is
* done by writing the value 0xAA to the base, then verifying that all
* power-of-two locations still contain 0x55.
*
* The address bus is then checked for lines that are stuck low or coupled. The
* base location is reinitialized with the value 0x55 before this test. The
* value 0xAA is then temporarily written to the individual power-of-two
* locations while the content of the others (base and power-of-two) are
* verified to still contain 0x55.
*
* \param test Current test case.
*/
void run_address_bus_test(const struct test_case *test)
{
struct ebi_test_params *params;
hugemem_ptr_t base;
uint32_t size;
uint32_t offset;
params = (struct ebi_test_params *)test_get_data();
base = params->base;
size = params->size;
// Initialize all power-of-two locations with 0x55
hugemem_write8(base, 0x55);
for (offset = 1; offset < size; offset <<= 1) {
hugemem_ptr_t p;
p = (hugemem_ptr_t)((uint32_t)base + offset);
hugemem_write8(p, 0x55);
}
// Check for address lines stuck high
hugemem_write8(base, 0xaa);
for (offset = 1; offset < size; offset <<= 1) {
hugemem_ptr_t p;
uint8_t actual;
p = (hugemem_ptr_t)((uint32_t)base + offset);
actual = hugemem_read8(p);
test_assert_true(test, actual == 0x55,
"Read 0x%02x @ 0x%08lx, expected 0x55 (stuck "
"high)",
actual, (uint32_t)p);
}
// Check for address lines stuck low or shorted
hugemem_write8(base, 0x55);
for (offset = 1; offset < size; offset <<= 1) {
hugemem_ptr_t p;
uint32_t offset2;
uint8_t actual;
p = (hugemem_ptr_t)((uint32_t)base + offset);
hugemem_write8(p, 0xaa);
actual = hugemem_read8(base);
test_assert_true(test, actual == 0x55,
"Read 0x%02x @ 0x%08lx after writing 0xaa @ "
"0x%08lx, expected 0x55 (stuck low or coupled)",
actual, (uint32_t)base, (uint32_t)p);
for (offset2 = 1; offset2 < size; offset2 <<= 1) {
hugemem_ptr_t q;
if (offset2 == offset)
continue;
q = (hugemem_ptr_t)((uint32_t)base + offset2);
actual = hugemem_read8(q);
test_assert_true(test, actual == 0x55,
"Read 0x%02x @ 0x%08lx after writing 0xaa"
" @ 0x%08lx, expected 0x55 (stuck low or "
"coupled)",
actual, (uint32_t)q, (uint32_t)p);
}
hugemem_write8(p, 0x55);
}
}
/**
* \brief Test the EBI address bus wired to the SDRAM
*
* This function will perform an address bus test to locate any shorts or open
* leads to the SDRAM device.
*
* \param base Base address of the external memory device
* \param size Size of the external memory device
*
* \retval STATUS_OK on success, and \ref status_code_t error code on failure
*/
static status_code_t ebi_test_addr_bus(hugemem_ptr_t base, uint32_t size)
{
uint32_t offset;
uint_fast8_t i;
/* Initialize all power-of-two locations with 0x55 */
hugemem_write8(base, 0x55);
for (offset = 1; offset < size; offset <<= 1) {
hugemem_ptr_t p;
p = (hugemem_ptr_t)((uint32_t)base + offset);
hugemem_write8(p, 0x55);
}
/* Check for address lines stuck high */
hugemem_write8(base, 0xaa);
for (i = 0, offset = 1; offset < size; offset <<= 1, i++) {
hugemem_ptr_t p;
uint8_t actual;
p = (hugemem_ptr_t)((uint32_t)base + offset);
actual = hugemem_read8(p);
if (actual != 0x55) {
return ERR_IO_ERROR;
}
}
/* Check for address lines stuck low or shorted */
hugemem_write8(base, 0x55);
for (i = 0, offset = 1; offset < size; offset <<= 1, i++) {
hugemem_ptr_t p;
uint32_t offset2;
uint_fast8_t j;
uint8_t actual;
p = (hugemem_ptr_t)((uint32_t)base + offset);
hugemem_write8(p, 0xaa);
actual = hugemem_read8(base);
if (actual != 0x55) {
return ERR_IO_ERROR;
}
for (j = 0, offset2 = 1; offset2 < size; offset2 <<= 1, j++) {
hugemem_ptr_t q;
if (offset2 == offset)
continue;
q = (hugemem_ptr_t)((uint32_t)base + offset2);
actual = hugemem_read8(q);
if (actual != 0x55) {
return ERR_IO_ERROR;
}
}
hugemem_write8(p, 0x55);
}
return STATUS_OK;
}
