22 Feb, 2018

1 commit

  • Currently a number of Makefiles break when used with toolchains that
    pass extra flags in CC and other cross-compile related variables (such
    as --sysroot).

    Thus we get this error when we use a toolchain that puts --sysroot in
    the CC var:

    ~/src/linux/tools$ make iio
    [snip]
    iio_event_monitor.c:18:10: fatal error: unistd.h: No such file or directory
    #include
    ^~~~~~~~~~

    This occurs because we clobber several env vars related to
    cross-compiling with lines like this:

    CC = $(CROSS_COMPILE)gcc

    Although this will point to a valid cross-compiler, we lose any extra
    flags that might exist in the CC variable, which can break toolchains
    that rely on them (for example, those that use --sysroot).

    This easily shows up using a Yocto SDK:

    $ . [snip]/sdk/environment-setup-cortexa8hf-neon-poky-linux-gnueabi

    $ echo $CC
    arm-poky-linux-gnueabi-gcc -march=armv7-a -mfpu=neon -mfloat-abi=hard
    -mcpu=cortex-a8
    --sysroot=[snip]/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi

    $ echo $CROSS_COMPILE
    arm-poky-linux-gnueabi-

    $ echo ${CROSS_COMPILE}gcc
    krm-poky-linux-gnueabi-gcc

    Although arm-poky-linux-gnueabi-gcc is a cross-compiler, we've lost the
    --sysroot and other flags that enable us to find the right libraries to
    link against, so we can't find unistd.h and other libraries and headers.
    Normally with the --sysroot flag we would find unistd.h in the sdk
    directory in the sysroot:

    $ find [snip]/sdk/sysroots -path '*/usr/include/unistd.h'
    [snip]/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi/usr/include/unistd.h

    The perf Makefile adds CC = $(CROSS_COMPILE)gcc if and only if CC is not
    already set, and it compiles correctly with the above toolchain.

    So, generalize the logic that perf uses in the common Makefile and
    remove the manual CC = $(CROSS_COMPILE)gcc lines from each Makefile.

    Note that this patch does not fix cross-compile for all the tools (some
    have other bugs), but it does fix it for all except usb and acpi, which
    still have other unrelated issues.

    I tested both with and without the patch on native and cross-build and
    there appear to be no regressions.

    Link: http://lkml.kernel.org/r/20180107214028.23771-1-martin@martingkelly.com
    Signed-off-by: Martin Kelly
    Acked-by: Mark Brown
    Cc: Tejun Heo
    Cc: Li Zefan
    Cc: Johannes Weiner
    Cc: Linus Walleij
    Cc: "K. Y. Srinivasan"
    Cc: Haiyang Zhang
    Cc: Stephen Hemminger
    Cc: Jonathan Cameron
    Cc: Pali Rohar
    Cc: Richard Purdie
    Cc: Jacek Anaszewski
    Cc: Pavel Machek
    Cc: Peter Zijlstra
    Cc: Ingo Molnar
    Cc: Arnaldo Carvalho de Melo
    Cc: Robert Moore
    Cc: Lv Zheng
    Cc: "Rafael J. Wysocki"
    Cc: Greg Kroah-Hartman
    Cc: Valentina Manea
    Cc: Shuah Khan
    Cc: Mario Limonciello
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Martin Kelly
     

02 Nov, 2017

1 commit

  • Many source files in the tree are missing licensing information, which
    makes it harder for compliance tools to determine the correct license.

    By default all files without license information are under the default
    license of the kernel, which is GPL version 2.

    Update the files which contain no license information with the 'GPL-2.0'
    SPDX license identifier. The SPDX identifier is a legally binding
    shorthand, which can be used instead of the full boiler plate text.

    This patch is based on work done by Thomas Gleixner and Kate Stewart and
    Philippe Ombredanne.

    How this work was done:

    Patches were generated and checked against linux-4.14-rc6 for a subset of
    the use cases:
    - file had no licensing information it it.
    - file was a */uapi/* one with no licensing information in it,
    - file was a */uapi/* one with existing licensing information,

    Further patches will be generated in subsequent months to fix up cases
    where non-standard license headers were used, and references to license
    had to be inferred by heuristics based on keywords.

    The analysis to determine which SPDX License Identifier to be applied to
    a file was done in a spreadsheet of side by side results from of the
    output of two independent scanners (ScanCode & Windriver) producing SPDX
    tag:value files created by Philippe Ombredanne. Philippe prepared the
    base worksheet, and did an initial spot review of a few 1000 files.

    The 4.13 kernel was the starting point of the analysis with 60,537 files
    assessed. Kate Stewart did a file by file comparison of the scanner
    results in the spreadsheet to determine which SPDX license identifier(s)
    to be applied to the file. She confirmed any determination that was not
    immediately clear with lawyers working with the Linux Foundation.

    Criteria used to select files for SPDX license identifier tagging was:
    - Files considered eligible had to be source code files.
    - Make and config files were included as candidates if they contained >5
    lines of source
    - File already had some variant of a license header in it (even if
    Reviewed-by: Philippe Ombredanne
    Reviewed-by: Thomas Gleixner
    Signed-off-by: Greg Kroah-Hartman

    Greg Kroah-Hartman
     

11 Dec, 2016

1 commit


23 Jun, 2016

2 commits


15 Jun, 2016

2 commits

  • The gpio-event-mon is used from userspace as an example of how
    to monitor GPIO line events. It will latch on to a certain
    GPIO line on a certain gpiochip and print timestamped events
    as they arrive.

    Example output:
    $ gpio-event-mon -n gpiochip2 -o 0 -r -f
    Monitoring line 0 on gpiochip2
    Initial line value: 1
    GPIO EVENT 946685798487609863: falling edge
    GPIO EVENT 946685798732482910: rising edge
    GPIO EVENT 946685799115997314: falling edge
    GPIO EVENT 946685799381469726: rising edge

    Signed-off-by: Linus Walleij

    Linus Walleij
     
  • The gpio-hammer is used from userspace as an example of how
    to retrieve a GPIO handle for one or several GPIO lines and
    hammer the outputs from low to high and back again. It will
    pulse the selected lines once per second for a specified
    number of times or indefinitely if no loop count is
    supplied.

    Example output:
    $ gpio-hammer -n gpiochip0 -o5 -o6 -o7
    Hammer lines [5, 6, 7] on gpiochip0, initial states: [1, 1, 1]
    [-] [5: 0, 6: 0, 7: 0]

    Tested-by: Michael Welling
    Signed-off-by: Linus Walleij

    Linus Walleij
     

31 Mar, 2016

1 commit


09 Feb, 2016

1 commit

  • This creates GPIO tools under tools/gpio/* and adds a single
    example program to list the GPIOs on a system. When proper
    devices are created it provides this minimal output:

    Cc: Johan Hovold
    Cc: Michael Welling
    Cc: Markus Pargmann
    Signed-off-by: Linus Walleij

    Linus Walleij