From 80b81d783772a87000356f126cb47dc429a95f3d Mon Sep 17 00:00:00 2001
From: Alessandro Rubini <rubini@gnudd.com>
Date: Tue, 6 Mar 2012 10:42:17 +0100
Subject: [PATCH 15/19] memtest: copied from barebox (our version)

---
 lib/memtest.c |  355 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 355 insertions(+)
 create mode 100644 lib/memtest.c

diff --git a/lib/memtest.c b/lib/memtest.c
new file mode 100644
index 0000000..d9c8b3d
--- /dev/null
+++ b/lib/memtest.c
@@ -0,0 +1,355 @@
+/*
+ * mtest - Perform a memory test
+ *
+ * (C) Copyright 2000
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <command.h>
+#include <types.h>
+
+/*
+ * Perform a memory test. A more complete alternative test can be
+ * configured using CONFIG_CMD_MTEST_ALTERNATIVE. The complete test
+ * loops until interrupted by ctrl-c or by a failure of one of the
+ * sub-tests.
+ */
+#ifdef CONFIG_CMD_MTEST_ALTERNATIVE
+static int mem_test(ulong _start, ulong _end, ulong pattern_unused)
+{
+	vu_long *start = (vu_long *)_start;
+	vu_long *end   = (vu_long *)_end;
+	vu_long *addr;
+	ulong	val;
+	ulong	readback;
+	vu_long	addr_mask;
+	vu_long	offset;
+	vu_long	test_offset;
+	vu_long	pattern;
+	vu_long	temp;
+	vu_long	anti_pattern;
+	vu_long	num_words;
+#ifdef CFG_MEMTEST_SCRATCH
+	vu_long *dummy = (vu_long*)CFG_MEMTEST_SCRATCH;
+#else
+	vu_long *dummy = start;
+#endif
+	int	j;
+	int iterations = 1;
+
+	static const ulong bitpattern[] = {
+		0x00000001,	/* single bit */
+		0x00000003,	/* two adjacent bits */
+		0x00000007,	/* three adjacent bits */
+		0x0000000F,	/* four adjacent bits */
+		0x00000005,	/* two non-adjacent bits */
+		0x00000015,	/* three non-adjacent bits */
+		0x00000055,	/* four non-adjacent bits */
+		0xaaaaaaaa,	/* alternating 1/0 */
+	};
+
+	/* XXX: enforce alignment of start and end? */
+	for (;;) {
+		if (ctrlc()) {
+			putchar ('\n');
+			return 1;
+		}
+
+		printf("Iteration: %6d\r", iterations);
+		iterations++;
+
+		/*
+		 * Data line test: write a pattern to the first
+		 * location, write the 1's complement to a 'parking'
+		 * address (changes the state of the data bus so a
+		 * floating bus doen't give a false OK), and then
+		 * read the value back. Note that we read it back
+		 * into a variable because the next time we read it,
+		 * it might be right (been there, tough to explain to
+		 * the quality guys why it prints a failure when the
+		 * "is" and "should be" are obviously the same in the
+		 * error message).
+		 *
+		 * Rather than exhaustively testing, we test some
+		 * patterns by shifting '1' bits through a field of
+		 * '0's and '0' bits through a field of '1's (i.e.
+		 * pattern and ~pattern).
+		 */
+		addr = start;
+		/* XXX */
+		if (addr == dummy) ++addr;
+		for (j = 0; j < sizeof(bitpattern)/sizeof(bitpattern[0]); j++) {
+		    val = bitpattern[j];
+		    for(; val != 0; val <<= 1) {
+			*addr  = val;
+			*dummy  = ~val; /* clear the test data off of the bus */
+			readback = *addr;
+			if(readback != val) {
+			     printf ("FAILURE (data line): "
+				"expected 0x%08lx, actual 0x%08lx at address 0x%p\n",
+					  val, readback, addr);
+			}
+			*addr  = ~val;
+			*dummy  = val;
+			readback = *addr;
+			if(readback != ~val) {
+			    printf ("FAILURE (data line): "
+				"Is 0x%08lx, should be 0x%08lx at address 0x%p\n",
+					readback, ~val, addr);
+			}
+		    }
+		}
+
+		/*
+		 * Based on code whose Original Author and Copyright
+		 * information follows: Copyright (c) 1998 by Michael
+		 * Barr. This software is placed into the public
+		 * domain and may be used for any purpose. However,
+		 * this notice must not be changed or removed and no
+		 * warranty is either expressed or implied by its
+		 * publication or distribution.
+		 */
+
+		/*
+		 * Address line test
+		 *
+		 * Description: Test the address bus wiring in a
+		 *              memory region by performing a walking
+		 *              1's test on the relevant bits of the
+		 *              address and checking for aliasing.
+		 *              This test will find single-bit
+		 *              address failures such as stuck -high,
+		 *              stuck-low, and shorted pins. The base
+		 *              address and size of the region are
+		 *              selected by the caller.
+		 *
+		 * Notes:	For best results, the selected base
+		 *              address should have enough LSB 0's to
+		 *              guarantee single address bit changes.
+		 *              For example, to test a 64-Kbyte
+		 *              region, select a base address on a
+		 *              64-Kbyte boundary. Also, select the
+		 *              region size as a power-of-two if at
+		 *              all possible.
+		 *
+		 * Returns:     0 if the test succeeds, 1 if the test fails.
+		 *
+		 * ## NOTE ##	Be sure to specify start and end
+		 *              addresses such that addr_mask has
+		 *              lots of bits set. For example an
+		 *              address range of 01000000 02000000 is
+		 *              bad while a range of 01000000
+		 *              01ffffff is perfect.
+		 */
+		addr_mask = ((ulong)end - (ulong)start)/sizeof(vu_long);
+		pattern = (vu_long) 0xaaaaaaaa;
+		anti_pattern = (vu_long) 0x55555555;
+
+		debug("%s:%d: addr mask = 0x%.8lx\n",
+			__FUNCTION__, __LINE__,
+			addr_mask);
+		/*
+		 * Write the default pattern at each of the
+		 * power-of-two offsets.
+		 */
+		for (offset = 1; (offset & addr_mask) != 0; offset <<= 1)
+			start[offset] = pattern;
+
+		/*
+		 * Check for address bits stuck high.
+		 */
+		test_offset = 0;
+		start[test_offset] = anti_pattern;
+
+		for (offset = 1; (offset & addr_mask) != 0; offset <<= 1) {
+		    temp = start[offset];
+		    if (temp != pattern) {
+			printf ("\nFAILURE: Address bit stuck high @ 0x%.8lx:"
+				" expected 0x%.8lx, actual 0x%.8lx\n",
+				(ulong)&start[offset], pattern, temp);
+			return 1;
+		    }
+		}
+		start[test_offset] = pattern;
+
+		/*
+		 * Check for addr bits stuck low or shorted.
+		 */
+		for (test_offset = 1; (test_offset & addr_mask) != 0; test_offset <<= 1) {
+		    start[test_offset] = anti_pattern;
+
+		    for (offset = 1; (offset & addr_mask) != 0; offset <<= 1) {
+			temp = start[offset];
+			if ((temp != pattern) && (offset != test_offset)) {
+			    printf ("\nFAILURE: Address bit stuck low or shorted @"
+				" 0x%.8lx: expected 0x%.8lx, actual 0x%.8lx\n",
+				(ulong)&start[offset], pattern, temp);
+			    return 1;
+			}
+		    }
+		    start[test_offset] = pattern;
+		}
+
+		/*
+		 * Description: Test the integrity of a physical
+		 *		memory device by performing an
+		 *		increment/decrement test over the
+		 *		entire region. In the process every
+		 *		storage bit in the device is tested
+		 *		as a zero and a one. The base address
+		 *		and the size of the region are
+		 *		selected by the caller.
+		 *
+		 * Returns:     0 if the test succeeds, 1 if the test fails.
+		 */
+		num_words = ((ulong)end - (ulong)start)/sizeof(vu_long) + 1;
+
+		/*
+		 * Fill memory with a known pattern.
+		 */
+		for (pattern = 1, offset = 0; offset < num_words; pattern++, offset++) {
+			start[offset] = pattern;
+		}
+
+		/*
+		 * Check each location and invert it for the second pass.
+		 */
+		for (pattern = 1, offset = 0; offset < num_words; pattern++, offset++) {
+		    temp = start[offset];
+		    if (temp != pattern) {
+			printf ("\nFAILURE (read/write) @ 0x%.8lx:"
+				" expected 0x%.8lx, actual 0x%.8lx)\n",
+				(ulong)&start[offset], pattern, temp);
+			return 1;
+		    }
+
+		    anti_pattern = ~pattern;
+		    start[offset] = anti_pattern;
+		}
+
+		/*
+		 * Check each location for the inverted pattern and zero it.
+		 */
+		for (pattern = 1, offset = 0; offset < num_words; pattern++, offset++) {
+		    anti_pattern = ~pattern;
+		    temp = start[offset];
+		    if (temp != anti_pattern) {
+			printf ("\nFAILURE (read/write): @ 0x%.8lx:"
+				" expected 0x%.8lx, actual 0x%.8lx)\n",
+				(ulong)&start[offset], anti_pattern, temp);
+			return 1;
+		    }
+		    start[offset] = 0;
+		}
+	}
+
+}
+#else
+static int mem_test(ulong _start, ulong _end, ulong pattern)
+{
+	vu_long	*addr;
+	vu_long *start = (vu_long *)_start;
+	vu_long *end   = (vu_long *)_end;
+	ulong	val;
+	ulong	readback;
+	ulong	incr;
+	int rcode;
+
+	incr = 1;
+	for (;;) {
+		if (ctrlc()) {
+			putchar('\n');
+			return 1;
+		}
+
+		printf ("\rPattern 0x%08lX  Writing..."
+			"%12s"
+			"\b\b\b\b\b\b\b\b\b\b",
+			pattern, "");
+
+		for (addr=start,val=pattern; addr<end; addr++) {
+			*addr = val;
+			val  += incr;
+		}
+
+		puts ("Reading...");
+
+		for (addr=start,val=pattern; addr<end; addr++) {
+			readback = *addr;
+			if (readback != val) {
+				printf ("\nMem error @ 0x%08X: "
+					"found 0x%08lX, expected 0x%08lX\n",
+					(uint)addr, readback, val);
+				rcode = 1;
+			}
+			val += incr;
+		}
+
+		/*
+		 * Flip the pattern each time to make lots of zeros and
+		 * then, the next time, lots of ones.  We decrement
+		 * the "negative" patterns and increment the "positive"
+		 * patterns to preserve this feature.
+		 */
+		if(pattern & 0x80000000) {
+			pattern = -pattern;	/* complement & increment */
+		}
+		else {
+			pattern = ~pattern;
+		}
+		incr = -incr;
+	}
+	return rcode;
+}
+#endif
+
+static int do_mem_mtest(struct command *cmdtp, int argc, char *argv[])
+{
+	ulong start, end, pattern = 0;
+
+	if (argc < 3)
+		return COMMAND_ERROR_USAGE;
+
+	start = simple_strtoul(argv[1], NULL, 0);
+	end = simple_strtoul(argv[2], NULL, 0);
+
+	if (argc > 3)
+		pattern = simple_strtoul(argv[3], NULL, 0);
+
+	printf ("Testing 0x%08x ... 0x%08x:\n", (uint)start, (uint)end);
+	
+	return mem_test(start, end, pattern);
+}
+
+static const __maybe_unused char cmd_mtest_help[] =
+"Usage: <start> <end> "
+#ifdef CONFIG_CMD_MTEST_ALTERNATIVE
+"[pattern]"
+#endif
+"\nsimple RAM read/write test\n";
+
+BAREBOX_CMD_START(mtest)
+	.cmd		= do_mem_mtest,
+	.usage		= "simple RAM test",
+	BAREBOX_CMD_HELP(cmd_mtest_help)
+BAREBOX_CMD_END
+
-- 
1.7.9.5

