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author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-02-21 02:28:57 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-02-21 02:28:57 +0300 |
commit | ff0c7e18629b8bd64681313a88ce55e182c9fee6 (patch) | |
tree | 70efa650f6458514e1d7e5e3f72cc8f87fc5cf2c /Documentation/arm/samsung-s3c24xx/suspend.rst | |
parent | 5b0ed5964928b0aaf0d644c17c886c7f5ea4bb3f (diff) | |
parent | a1f925bc4fa899b3c0f2dcbc432d572c36e74e71 (diff) | |
download | linux-ff0c7e18629b8bd64681313a88ce55e182c9fee6.tar.xz |
Merge tag 'arm-boardfile-remove-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc
Pull ARM SoC boardfile updates from Arnd Bergmann
"Unused boardfile removal for 6.3
This is a follow-up to the deprecation of most of the old-style board
files that was merged in linux-6.0, removing them for good.
This branch is almost exclusively dead code removal based on those
annotations. Some device driver removals went through separate
subsystem trees, but the majority is in the same branch, in order to
better handle dependencies between the patches and avoid breaking
bisection.
Unfortunately that leads to merge conflicts against other changes in
the subsystem trees, but they should all be trivial to resolve by
removing the files.
See commit 7d0d3fa7339e ("Merge tag 'arm-boardfiles-6.0' of
git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc") for the
description of which machines were marked unused and are now removed.
The only removals that got postponed are Terastation WXL (mv78xx0) and
Jornada720 (StrongARM1100), which turned out to still have potential
users"
* tag 'arm-boardfile-remove-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (91 commits)
mmc: omap: drop TPS65010 dependency
ARM: pxa: restore mfp-pxa320.h
usb: ohci-omap: avoid unused-variable warning
ARM: debug: remove references in DEBUG_UART_8250_SHIFT to removed configs
ARM: s3c: remove obsolete s3c-cpu-freq header
MAINTAINERS: adjust SAMSUNG SOC CLOCK DRIVERS after s3c24xx support removal
MAINTAINERS: update file entries after arm multi-platform rework and mach-pxa removal
ARM: remove CONFIG_UNUSED_BOARD_FILES
mfd: remove htc-pasic3 driver
w1: remove ds1wm driver
usb: remove ohci-tmio driver
fbdev: remove w100fb driver
fbdev: remove tmiofb driver
mmc: remove tmio_mmc driver
mfd: remove ucb1400 support
mfd: remove toshiba tmio drivers
rtc: remove v3020 driver
power: remove pda_power supply driver
ASoC: pxa: remove unused board support
pcmcia: remove unused pxa/sa1100 drivers
...
Diffstat (limited to 'Documentation/arm/samsung-s3c24xx/suspend.rst')
-rw-r--r-- | Documentation/arm/samsung-s3c24xx/suspend.rst | 137 |
1 files changed, 0 insertions, 137 deletions
diff --git a/Documentation/arm/samsung-s3c24xx/suspend.rst b/Documentation/arm/samsung-s3c24xx/suspend.rst deleted file mode 100644 index b4f3ae9fe76e..000000000000 --- a/Documentation/arm/samsung-s3c24xx/suspend.rst +++ /dev/null @@ -1,137 +0,0 @@ -======================= -S3C24XX Suspend Support -======================= - - -Introduction ------------- - - The S3C24XX supports a low-power suspend mode, where the SDRAM is kept - in Self-Refresh mode, and all but the essential peripheral blocks are - powered down. For more information on how this works, please look - at the relevant CPU datasheet from Samsung. - - -Requirements ------------- - - 1) A bootloader that can support the necessary resume operation - - 2) Support for at least 1 source for resume - - 3) CONFIG_PM enabled in the kernel - - 4) Any peripherals that are going to be powered down at the same - time require suspend/resume support. - - -Resuming --------- - - The S3C2410 user manual defines the process of sending the CPU to - sleep and how it resumes. The default behaviour of the Linux code - is to set the GSTATUS3 register to the physical address of the - code to resume Linux operation. - - GSTATUS4 is currently left alone by the sleep code, and is free to - use for any other purposes (for example, the EB2410ITX uses this to - save memory configuration in). - - -Machine Support ---------------- - - The machine specific functions must call the s3c_pm_init() function - to say that its bootloader is capable of resuming. This can be as - simple as adding the following to the machine's definition: - - INITMACHINE(s3c_pm_init) - - A board can do its own setup before calling s3c_pm_init, if it - needs to setup anything else for power management support. - - There is currently no support for over-riding the default method of - saving the resume address, if your board requires it, then contact - the maintainer and discuss what is required. - - Note, the original method of adding an late_initcall() is wrong, - and will end up initialising all compiled machines' pm init! - - The following is an example of code used for testing wakeup from - an falling edge on IRQ_EINT0:: - - - static irqreturn_t button_irq(int irq, void *pw) - { - return IRQ_HANDLED; - } - - statuc void __init machine_init(void) - { - ... - - request_irq(IRQ_EINT0, button_irq, IRQF_TRIGGER_FALLING, - "button-irq-eint0", NULL); - - enable_irq_wake(IRQ_EINT0); - - s3c_pm_init(); - } - - -Debugging ---------- - - There are several important things to remember when using PM suspend: - - 1) The uart drivers will disable the clocks to the UART blocks when - suspending, which means that use of printascii() or similar direct - access to the UARTs will cause the debug to stop. - - 2) While the pm code itself will attempt to re-enable the UART clocks, - care should be taken that any external clock sources that the UARTs - rely on are still enabled at that point. - - 3) If any debugging is placed in the resume path, then it must have the - relevant clocks and peripherals setup before use (ie, bootloader). - - For example, if you transmit a character from the UART, the baud - rate and uart controls must be setup beforehand. - - -Configuration -------------- - - The S3C2410 specific configuration in `System Type` defines various - aspects of how the S3C2410 suspend and resume support is configured - - `S3C2410 PM Suspend debug` - - This option prints messages to the serial console before and after - the actual suspend, giving detailed information on what is - happening - - - `S3C2410 PM Suspend Memory CRC` - - Allows the entire memory to be checksummed before and after the - suspend to see if there has been any corruption of the contents. - - Note, the time to calculate the CRC is dependent on the CPU speed - and the size of memory. For an 64Mbyte RAM area on an 200MHz - S3C2410, this can take approximately 4 seconds to complete. - - This support requires the CRC32 function to be enabled. - - - `S3C2410 PM Suspend CRC Chunksize (KiB)` - - Defines the size of memory each CRC chunk covers. A smaller value - will mean that the CRC data block will take more memory, but will - identify any faults with better precision - - -Document Author ---------------- - -Ben Dooks, Copyright 2004 Simtec Electronics |