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11da3403e9
For nearly all commands in U-Boot the '?' variable is handled the same way with 0 meaning success, 1 meaning any failure. Explain this in the general rules section of the cmdline documentation (with a link to a counter example) and then remove the redundant wording from most commands. We retain a section about the return value in a number of places where we are doing something such as always returning a specific value or we have useful additional information to go along with the normal return codes. Signed-off-by: Tom Rini <trini@konsulko.com> Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
65 lines
1.7 KiB
ReStructuredText
65 lines
1.7 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+
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.. Copyright 2022, Heinrich Schuchardt <xypron.glpk@gmx.de>
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.. index::
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single: mtest (command)
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mtest command
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=============
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Synopsis
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--------
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::
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mtest [start [end [pattern [iterations]]]]
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Description
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-----------
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The *mtest* command tests the random access memory. It writes long values, reads
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them back and checks for differences. The test can be interrupted with CTRL+C.
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The default test uses *pattern* as first value to be written and varies it
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between memory addresses.
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An alternative test can be selected with CONFIG_SYS_ALT_MEMTEST=y. It uses
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multiple hard coded bit patterns.
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With CONFIGSYS_ALT_MEMTEST_BITFLIP=y a further test is executed. It writes long
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values offset by half the size of long and checks if writing to the one address
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causes bit flips at the other address.
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start
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start address of the memory range tested, defaults to
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CONFIG_SYS_MEMTEST_START
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end
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end address of the memory range tested, defaults to
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CONFIG_SYS_MEMTEST_END. If CONFIGSYS_ALT_MEMTEST_BITFLIP=y, a value will
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be written to this address. Otherwise it is excluded from the range.
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pattern
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pattern to be written to memory. This is a 64bit value on 64bit systems
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and a 32bit value on 32bit systems. It defaults to 0. The value is
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ignored if CONFIG_SYS_ALT_MEMTEST=y.
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iterations
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number of test repetitions. If the value is not provided the test will
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not terminate automatically. Enter CTRL+C instead.
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Examples
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--------
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::
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=> mtest 1000 2000 0x55aa55aa55aa55aa 10
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Testing 00001000 ... 00002000:
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Pattern AA55AA55AA55AA55 Writing... Reading...
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Tested 16 iteration(s) with 0 errors.
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Configuration
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-------------
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The mtest command is enabled by CONFIG_CMD_MEMTEST=y.
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