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* (C) Copyright 2002-2003
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* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
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* See file CREDITS for list of people who contributed to this
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* General observations:
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* o The recommended test sequence is to test the data lines: if they are
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* broken, nothing else will work properly. Then test the address
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* lines. Finally, test the cells in the memory now that the test
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* program knows that the address and data lines work properly.
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* This sequence also helps isolate and identify what is faulty.
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* o For the address line test, it is a good idea to use the base
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* address of the lowest memory location, which causes a '1' bit to
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* walk through a field of zeros on the address lines and the highest
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* memory location, which causes a '0' bit to walk through a field of
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* '1's on the address line.
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* o Floating buses can fool memory tests if the test routine writes
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* a value and then reads it back immediately. The problem is, the
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* write will charge the residual capacitance on the data bus so the
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* bus retains its state briefely. When the test program reads the
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* value back immediately, the capacitance of the bus can allow it
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* to read back what was written, even though the memory circuitry
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* is broken. To avoid this, the test program should write a test
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* pattern to the target location, write a different pattern elsewhere
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* to charge the residual capacitance in a differnt manner, then read
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* the target location back.
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* o Always read the target location EXACTLY ONCE and save it in a local
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* variable. The problem with reading the target location more than
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* once is that the second and subsequent reads may work properly,
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* resulting in a failed test that tells the poor technician that
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* "Memory error at 00000000, wrote aaaaaaaa, read aaaaaaaa" which
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* doesn't help him one bit and causes puzzled phone calls. Been there,
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* This tests data lines for shorts and opens by forcing adjacent data
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* to opposite states. Because the data lines could be routed in an
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* arbitrary manner the must ensure test patterns ensure that every case
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* is tested. By using the following series of binary patterns every
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* combination of adjacent bits is test regardless of routing.
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* ...101010101010101010101010
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* ...110011001100110011001100
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* ...111100001111000011110000
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* ...111111110000000011111111
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* Carrying this out, gives us six hex patterns as follows:
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* To test for short and opens to other signals on our boards, we
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* simply test with the 1's complemnt of the paterns as well, resulting
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* in twelve patterns total.
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* After writing a test pattern. a special pattern 0x0123456789ABCDEF is
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* written to a different address in case the data lines are floating.
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* Thus, if a byte lane fails, you will see part of the special
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* pattern in that byte lane when the test runs. For example, if the
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* xx__xxxxxxxxxxxx byte line fails, you will see aa23aaaaaaaaaaaa
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* (for the 'a' test pattern).
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* This function performs a test to verify that all the address lines
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* hooked up to the RAM work properly. If there is an address line
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* fault, it usually shows up as two different locations in the address
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* map (related by the faulty address line) mapping to one physical
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* memory storage location. The artifact that shows up is writing to
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* the first location "changes" the second location.
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* To test all address lines, we start with the given base address and
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* xor the address with a '1' bit to flip one address line. For each
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* test, we shift the '1' bit left to test the next address line.
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* In the actual code, we start with address sizeof(ulong) since our
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* test pattern we use is a ulong and thus, if we tried to test lower
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* order address bits, it wouldn't work because our pattern would
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* Example for a 4 bit address space with the base at 0000:
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* Example for a 4 bit address space with the base at 0010:
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* 0000 <- (below the base address, skipped)
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* The test locations are successively tested to make sure that they are
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* not "mirrored" onto the base address due to a faulty address line.
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* Note that the base and each test location are related by one address
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* line flipped. Note that the base address need not be all zeros.
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* These tests verify RAM using sequential writes and reads
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* to/from RAM. There are several test cases that use different patterns to
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* verify RAM. Each test case fills a region of RAM with one pattern and
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* then reads the region back and compares its contents with the pattern.
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* The following patterns are used:
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* 1a) zero pattern (0x00000000)
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* 1b) negative pattern (0xffffffff)
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* 1c) checkerboard pattern (0x55555555)
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* 1d) checkerboard pattern (0xaaaaaaaa)
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* 2) bit-flip pattern ((1 << (offset % 32))
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* 3) address pattern (offset)
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* 4) address pattern (~offset)
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* Being run in normal mode, the test verifies only small 4Kb
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* regions of RAM around each 1Mb boundary. For example, for 64Mb
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* RAM the following areas are verified: 0x00000000-0x00000800,
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* 0x000ff800-0x00100800, 0x001ff800-0x00200800, ..., 0x03fff800-
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* 0x04000000. If the test is run in slow-test mode, it verifies
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/* #ifdef CONFIG_POST */
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#include <watchdog.h>
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/* #if CONFIG_POST & CONFIG_SYS_POST_MEMORY */
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* Define INJECT_*_ERRORS for testing error detection in the presence of
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#undef INJECT_DATA_ERRORS
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#undef INJECT_ADDRESS_ERRORS
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#ifdef INJECT_DATA_ERRORS
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#warning "Injecting data line errors for testing purposes"
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#ifdef INJECT_ADDRESS_ERRORS
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#warning "Injecting address line errors for testing purposes"
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* This function performs a double word move from the data at
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* the source pointer to the location at the destination pointer.
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* This is helpful for testing memory on processors which have a 64 bit
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* On those PowerPC with FPU, use assembly and a floating point move:
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* this does a 64 bit move.
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* For other processors, let the compiler generate the best code it can.
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static void move64(const unsigned long long *src, unsigned long long *dest)
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#if defined(CONFIG_MPC8260) || defined(CONFIG_MPC824X)
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asm ("lfd 0, 0(3)\n\t" /* fpr0 = *scr */
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"stfd 0, 0(4)" /* *dest = fpr0 */
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: : : "fr0" ); /* Clobbers fr0 */
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* This is 64 bit wide test patterns. Note that they reside in ROM
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* (which presumably works) and the tests write them to RAM which may
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* The "otherpattern" is written to drive the data bus to values other
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* than the test pattern. This is for detecting floating bus lines.
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const static unsigned long long pattern[] = {
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0xaaaaaaaaaaaaaaaaULL,
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0xccccccccccccccccULL,
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0xf0f0f0f0f0f0f0f0ULL,
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0xff00ff00ff00ff00ULL,
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0xffff0000ffff0000ULL,
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0xffffffff00000000ULL,
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0x00000000ffffffffULL,
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0x0000ffff0000ffffULL,
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0x00ff00ff00ff00ffULL,
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0x0f0f0f0f0f0f0f0fULL,
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0x3333333333333333ULL,
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0x5555555555555555ULL,
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const unsigned long long otherpattern = 0x0123456789abcdefULL;
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static int memory_post_dataline(unsigned long long * pmem)
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unsigned long long temp64;
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int num_patterns = sizeof(pattern)/ sizeof(pattern[0]);
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unsigned int hi, lo, pathi, patlo;
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for ( i = 0; i < num_patterns; i++) {
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move64(&(pattern[i]), pmem++);
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* Put a different pattern on the data lines: otherwise they
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* may float long enough to read back what we wrote.
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move64(&otherpattern, pmem--);
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move64(pmem, &temp64);
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#ifdef INJECT_DATA_ERRORS
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temp64 ^= 0x00008000;
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if (temp64 != pattern[i]){
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pathi = (pattern[i]>>32) & 0xffffffff;
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patlo = pattern[i] & 0xffffffff;
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hi = (temp64>>32) & 0xffffffff;
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lo = temp64 & 0xffffffff;
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printf ("Memory (date line) error at %08lx, "
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"wrote %08x%08x, read %08x%08x !\n",
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(ulong)pmem, pathi, patlo, hi, lo);
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static int memory_post_addrline(ulong *testaddr, ulong *base, ulong size)
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end = (ulong *)((ulong)base + size); /* pointer arith! */
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for(xor = sizeof(ulong); xor > 0; xor <<= 1) {
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target = (ulong *)((ulong)testaddr ^ xor);
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if((target >= base) && (target < end)) {
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*testaddr = ~*target;
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#ifdef INJECT_ADDRESS_ERRORS
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if(xor == 0x00008000) {
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readback = *testaddr;
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if(readback == *testaddr) {
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printf ("Memory (address line) error at %08lx<->%08lx, "
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"XOR value %08lx !\n",
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(ulong)testaddr, (ulong)target,
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static int memory_post_test1 (unsigned long start,
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ulong *mem = (ulong *) start;
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for (i = 0; i < size / sizeof (ulong); i++) {
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for (i = 0; i < size / sizeof (ulong) && ret == 0; i++) {
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if (readback != val) {
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printf ("Memory error at %08lx, "
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"wrote %08lx, read %08lx !\n",
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(ulong)(mem + i), val, readback);
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static int memory_post_test2 (unsigned long start, unsigned long size)
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ulong *mem = (ulong *) start;
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for (i = 0; i < size / sizeof (ulong); i++) {
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mem[i] = 1 << (i % 32);
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for (i = 0; i < size / sizeof (ulong) && ret == 0; i++) {
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if (readback != (1 << (i % 32))) {
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printf ("Memory error at %08lx, "
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"wrote %08x, read %08lx !\n",
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(ulong)(mem + i), 1 << (i % 32), readback);
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static int memory_post_test3 (unsigned long start, unsigned long size)
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ulong *mem = (ulong *) start;
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for (i = 0; i < size / sizeof (ulong); i++) {
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for (i = 0; i < size / sizeof (ulong) && ret == 0; i++) {
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printf ("Memory error at %08lx, "
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"wrote %08lx, read %08lx !\n",
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(ulong)(mem + i), i, readback);
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static int memory_post_test4 (unsigned long start, unsigned long size)
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ulong *mem = (ulong *) start;
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for (i = 0; i < size / sizeof (ulong); i++) {
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for (i = 0; i < size / sizeof (ulong) && ret == 0; i++) {
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if (readback != ~i) {
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printf ("Memory error at %08lx, "
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"wrote %08lx, read %08lx !\n",
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(ulong)(mem + i), ~i, readback);
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int memory_post_tests (unsigned long start, unsigned long size)
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ret = memory_post_dataline ((unsigned long long *)start);
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ret = memory_post_addrline ((ulong *)start, (ulong *)start, size);
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ret = memory_post_addrline ((ulong *)(start + size - 8),
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(ulong *)start, size);
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ret = memory_post_test1 (start, size, 0x00000000);
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ret = memory_post_test1 (start, size, 0xffffffff);
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ret = memory_post_test1 (start, size, 0x55555555);
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ret = memory_post_test1 (start, size, 0xaaaaaaaa);
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ret = memory_post_test2 (start, size);
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ret = memory_post_test3 (start, size);
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ret = memory_post_test4 (start, size);
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DECLARE_GLOBAL_DATA_PTR;
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int memory_post_test (int flags)
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phys_size_t memsize = (bd->bi_memsize >= 256 << 20 ?
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256 << 20 : bd->bi_memsize) - (1 << 20);
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if (flags & POST_SLOWTEST) {
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ret = memory_post_tests (CONFIG_SYS_SDRAM_BASE, memsize);
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} else { /* POST_NORMAL */
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for (i = 0; i < (memsize >> 20) && ret == 0; i++) {
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ret = memory_post_tests (i << 20, 0x800);
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ret = memory_post_tests ((i << 20) + 0xff800, 0x800);
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/* #endif */ /* CONFIG_POST & CONFIG_SYS_POST_MEMORY */
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/* #endif */ /* CONFIG_POST */