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mirror of https://github.com/edk2-porting/linux-next.git synced 2025-01-23 04:54:01 +08:00
linux-next/Documentation/arm
Linus Torvalds 38c23685b2 ARM: SoC driver updates for 4.17
The main addition this time around is the new ARM "SCMI" framework,
 which is the latest in a series of standards coming from ARM to do power
 management in a platform independent way. This has been through many
 review cycles, and it relies on a rather interesting way of using the
 mailbox subsystem, but in the end I agreed that Sudeep's version was
 the best we could do after all.
 
 Other changes include:
 
 - the ARM CCN driver is moved out of drivers/bus into drivers/perf,
   which makes more sense. Similarly, the performance monitoring
   portion of the CCI driver are moved the same way and cleaned up
   a little more.
 
 - a series of updates to the SCPI framework
 
 - support for the Mediatek mt7623a SoC in drivers/soc
 
 - support for additional NVIDIA Tegra hardware in drivers/soc
 
 - a new reset driver for Socionext Uniphier
 
 - lesser bug fixes in drivers/soc, drivers/tee, drivers/memory, and
   drivers/firmware and drivers/reset across platforms
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Merge tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

Pull ARM SoC driver updates from Arnd Bergmann:
 "The main addition this time around is the new ARM "SCMI" framework,
  which is the latest in a series of standards coming from ARM to do
  power management in a platform independent way.

  This has been through many review cycles, and it relies on a rather
  interesting way of using the mailbox subsystem, but in the end I
  agreed that Sudeep's version was the best we could do after all.

  Other changes include:

   - the ARM CCN driver is moved out of drivers/bus into drivers/perf,
     which makes more sense. Similarly, the performance monitoring
     portion of the CCI driver are moved the same way and cleaned up a
     little more.

   - a series of updates to the SCPI framework

   - support for the Mediatek mt7623a SoC in drivers/soc

   - support for additional NVIDIA Tegra hardware in drivers/soc

   - a new reset driver for Socionext Uniphier

   - lesser bug fixes in drivers/soc, drivers/tee, drivers/memory, and
     drivers/firmware and drivers/reset across platforms"

* tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (87 commits)
  reset: uniphier: add ethernet reset control support for PXs3
  reset: stm32mp1: Enable stm32mp1 reset driver
  dt-bindings: reset: add STM32MP1 resets
  reset: uniphier: add Pro4/Pro5/PXs2 audio systems reset control
  reset: imx7: add 'depends on HAS_IOMEM' to fix unmet dependency
  reset: modify the way reset lookup works for board files
  reset: add support for non-DT systems
  clk: scmi: use devm_of_clk_add_hw_provider() API and drop scmi_clocks_remove
  firmware: arm_scmi: prevent accessing rate_discrete uninitialized
  hwmon: (scmi) return -EINVAL when sensor information is unavailable
  amlogic: meson-gx-socinfo: Update soc ids
  soc/tegra: pmc: Use the new reset APIs to manage reset controllers
  soc: mediatek: update power domain data of MT2712
  dt-bindings: soc: update MT2712 power dt-bindings
  cpufreq: scmi: add thermal dependency
  soc: mediatek: fix the mistaken pointer accessed when subdomains are added
  soc: mediatek: add SCPSYS power domain driver for MediaTek MT7623A SoC
  soc: mediatek: avoid hardcoded value with bus_prot_mask
  dt-bindings: soc: add header files required for MT7623A SCPSYS dt-binding
  dt-bindings: soc: add SCPSYS binding for MT7623 and MT7623A SoC
  ...
2018-04-05 21:29:35 -07:00
..
keystone ARM: dts: keystone: k2l: fix kernel crash when clk_ignore_unused is not in bootargs 2015-11-23 10:36:27 -08:00
Marvell Documentation: arm: add Marvell Armada 7K and 8K families 2016-02-19 14:07:54 +01:00
Microchip Documentation: at91: Update Microchip SoC documentation 2018-02-28 16:21:51 +01:00
nwfpe Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
OMAP Documentation: ARM: List new omap MMC requirements 2015-10-12 16:23:34 -07:00
pxa ARM: pxa: make more mach/*.h files local 2015-12-01 21:52:50 +01:00
SA1100 Documentation: fix common spelling mistakes 2016-04-28 07:51:59 -06:00
Samsung Doc: ARM: Fix a typo in clksrc-change-registers.awk 2016-02-17 14:11:59 -07:00
Samsung-S3C24XX ARM: SAMSUNG: remove unused DMA infrastructure 2015-01-24 13:09:54 +09:00
SH-Mobile Documentation: Remove ZBOOT MMC/SDHI utility and docs 2015-02-24 06:45:25 +09:00
SPEAr Update Viresh Kumar's email address 2015-07-17 16:39:53 -07:00
sti ARM: STi: Add STiH418 SoC support 2015-01-16 13:10:21 +01:00
stm32 ARM: stm32: add initial support for STM32MP157 2018-03-05 09:08:43 +01:00
sunxi ARM: sunxi: add support for R40 SoC 2017-09-22 21:57:09 +02:00
VFP [PATCH] kernel Doc/ URL corrections 2005-11-22 09:14:30 -08:00
00-INDEX Doc: update 00-INDEX files to reflect the runnable code move 2016-10-10 07:12:09 -06:00
Booting docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00
cluster-pm-race-avoidance.txt ARM: mcpm: introduce helpers for platform coherency exit/setup 2013-04-24 10:37:00 -04:00
firmware.txt Documentation: arm: Replace use of virt_to_phys with __pa_symbol 2017-07-17 13:43:58 -06:00
Interrupts [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
IXP4xx Documentation/arm/IXP4xx fix a typo 2013-06-05 16:24:59 +02:00
kernel_mode_neon.txt ARM: 7825/1: document the use of NEON in kernel mode 2013-08-25 17:09:48 +01:00
kernel_user_helpers.txt Documentation: Fix multiple typo in Documentation 2012-03-07 16:08:24 +01:00
mem_alignment arm: Documentation: update a path name 2017-04-20 14:06:55 -06:00
memory.txt ARM: 8432/1: move VMALLOC_END from 0xff000000 to 0xff800000 2015-09-22 08:13:57 +01:00
Netwinder Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
Porting Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
README Documentation: arm: Update for DT-only platforms 2015-02-27 14:54:55 -07:00
Setup Fix simple typos 2006-03-24 18:13:37 +01:00
swp_emulation ARM: 6396/1: Add SWP/SWPB emulation for ARMv7 processors 2010-11-04 15:45:24 +00:00
tcm.txt ARM: 6225/1: make TCM allocation static and common for all archs 2010-07-27 10:42:38 +01:00
uefi.txt arm64 updates for 4.4: 2015-11-04 14:47:13 -08:00
vlocks.txt Doc: Change wikipedia's URL from http to https 2015-06-22 10:14:05 -06:00

			   ARM Linux 2.6
			   =============

    Please check <ftp://ftp.arm.linux.org.uk/pub/armlinux> for
    updates.

Compilation of kernel
---------------------

  In order to compile ARM Linux, you will need a compiler capable of
  generating ARM ELF code with GNU extensions.  GCC 3.3 is known to be
  a good compiler.  Fortunately, you needn't guess.  The kernel will report
  an error if your compiler is a recognized offender.

  To build ARM Linux natively, you shouldn't have to alter the ARCH = line
  in the top level Makefile.  However, if you don't have the ARM Linux ELF
  tools installed as default, then you should change the CROSS_COMPILE
  line as detailed below.

  If you wish to cross-compile, then alter the following lines in the top
  level make file:

    ARCH = <whatever>
	with
    ARCH = arm

	and

    CROSS_COMPILE=
	to
    CROSS_COMPILE=<your-path-to-your-compiler-without-gcc>
	eg.
    CROSS_COMPILE=arm-linux-

  Do a 'make config', followed by 'make Image' to build the kernel 
  (arch/arm/boot/Image).  A compressed image can be built by doing a 
  'make zImage' instead of 'make Image'.


Bug reports etc
---------------

  Please send patches to the patch system.  For more information, see
  http://www.arm.linux.org.uk/developer/patches/info.php Always include some
  explanation as to what the patch does and why it is needed.

  Bug reports should be sent to linux-arm-kernel@lists.arm.linux.org.uk,
  or submitted through the web form at
  http://www.arm.linux.org.uk/developer/ 

  When sending bug reports, please ensure that they contain all relevant
  information, eg. the kernel messages that were printed before/during
  the problem, what you were doing, etc.


Include files
-------------

  Several new include directories have been created under include/asm-arm,
  which are there to reduce the clutter in the top-level directory.  These
  directories, and their purpose is listed below:

   arch-*	machine/platform specific header files
   hardware	driver-internal ARM specific data structures/definitions
   mach		descriptions of generic ARM to specific machine interfaces
   proc-*	processor dependent header files (currently only two
		categories)


Machine/Platform support
------------------------

  The ARM tree contains support for a lot of different machine types.  To
  continue supporting these differences, it has become necessary to split
  machine-specific parts by directory.  For this, the machine category is
  used to select which directories and files get included (we will use
  $(MACHINE) to refer to the category)

  To this end, we now have arch/arm/mach-$(MACHINE) directories which are
  designed to house the non-driver files for a particular machine (eg, PCI,
  memory management, architecture definitions etc).  For all future
  machines, there should be a corresponding arch/arm/mach-$(MACHINE)/include/mach
  directory.


Modules
-------

  Although modularisation is supported (and required for the FP emulator),
  each module on an ARM2/ARM250/ARM3 machine when is loaded will take
  memory up to the next 32k boundary due to the size of the pages.
  Therefore, is modularisation on these machines really worth it?

  However, ARM6 and up machines allow modules to take multiples of 4k, and
  as such Acorn RiscPCs and other architectures using these processors can
  make good use of modularisation.


ADFS Image files
----------------

  You can access image files on your ADFS partitions by mounting the ADFS
  partition, and then using the loopback device driver.  You must have
  losetup installed.

  Please note that the PCEmulator DOS partitions have a partition table at
  the start, and as such, you will have to give '-o offset' to losetup.


Request to developers
---------------------

  When writing device drivers which include a separate assembler file, please
  include it in with the C file, and not the arch/arm/lib directory.  This
  allows the driver to be compiled as a loadable module without requiring
  half the code to be compiled into the kernel image.

  In general, try to avoid using assembler unless it is really necessary.  It
  makes drivers far less easy to port to other hardware.


ST506 hard drives
-----------------

  The ST506 hard drive controllers seem to be working fine (if a little
  slowly).  At the moment they will only work off the controllers on an
  A4x0's motherboard, but for it to work off a Podule just requires
  someone with a podule to add the addresses for the IRQ mask and the
  HDC base to the source.

  As of 31/3/96 it works with two drives (you should get the ADFS
  *configure harddrive set to 2). I've got an internal 20MB and a great
  big external 5.25" FH 64MB drive (who could ever want more :-) ).

  I've just got 240K/s off it (a dd with bs=128k); thats about half of what
  RiscOS gets; but it's a heck of a lot better than the 50K/s I was getting
  last week :-)

  Known bug: Drive data errors can cause a hang; including cases where
  the controller has fixed the error using ECC. (Possibly ONLY
  in that case...hmm).


1772 Floppy
-----------
  This also seems to work OK, but hasn't been stressed much lately.  It
  hasn't got any code for disc change detection in there at the moment which
  could be a bit of a problem!  Suggestions on the correct way to do this
  are welcome.


CONFIG_MACH_ and CONFIG_ARCH_
-----------------------------
  A change was made in 2003 to the macro names for new machines.
  Historically, CONFIG_ARCH_ was used for the bonafide architecture,
  e.g. SA1100, as well as implementations of the architecture,
  e.g. Assabet.  It was decided to change the implementation macros
  to read CONFIG_MACH_ for clarity.  Moreover, a retroactive fixup has
  not been made because it would complicate patching.

  Previous registrations may be found online.

    <http://www.arm.linux.org.uk/developer/machines/>

Kernel entry (head.S)
--------------------------
  The initial entry into the kernel is via head.S, which uses machine
  independent code.  The machine is selected by the value of 'r1' on
  entry, which must be kept unique.

  Due to the large number of machines which the ARM port of Linux provides
  for, we have a method to manage this which ensures that we don't end up
  duplicating large amounts of code.

  We group machine (or platform) support code into machine classes.  A
  class typically based around one or more system on a chip devices, and
  acts as a natural container around the actual implementations.  These
  classes are given directories - arch/arm/mach-<class> and
  arch/arm/mach-<class> - which contain the source files to/include/mach
  support the machine class.  This directories also contain any machine
  specific supporting code.

  For example, the SA1100 class is based upon the SA1100 and SA1110 SoC
  devices, and contains the code to support the way the on-board and off-
  board devices are used, or the device is setup, and provides that
  machine specific "personality."

  For platforms that support device tree (DT), the machine selection is
  controlled at runtime by passing the device tree blob to the kernel.  At
  compile-time, support for the machine type must be selected.  This allows for
  a single multiplatform kernel build to be used for several machine types.

  For platforms that do not use device tree, this machine selection is
  controlled by the machine type ID, which acts both as a run-time and a
  compile-time code selection method.  You can register a new machine via the
  web site at:

    <http://www.arm.linux.org.uk/developer/machines/>

  Note: Please do not register a machine type for DT-only platforms.  If your
  platform is DT-only, you do not need a registered machine type.

---
Russell King (15/03/2004)