Allow SoCs to enable the scatterlist chaining support, which allows
scatterlist tables to be broken up into smaller allocations.

As support for this feature depends on the implementation details of
the users of the scatterlists, we can't enable this globally without
auditing all the users, which is a very big task.  Instead, let SoCs
progressively switch over to using this.

SoC drivers using scatterlists and SoC DMA implementations need
auditing before this option can be enabled for the SoC.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

There are more architectures that don't support ARCH_HAS_SG_CHAIN than
those that support it.  This removes removes ARCH_HAS_SG_CHAIN in
asm-generic/scatterlist.h and lets arhictectures to define it.

It's clearer than defining ARCH_HAS_SG_CHAIN asm-generic/scatterlist.h and
undefing it in arhictectures that don't support it.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move platform independent header files to arch/arm/include/asm, leaving
those in asm/arch* and asm/plat* alone.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add a Kconfig entry which will toggle some sanity checks on the sg
entry and tables.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Change the page member of the scatterlist structure to be an unsigned
long, and encode more stuff in the lower bits:

- Bits 0 and 1 zero: this is a normal sg entry. Next sg entry is located
  at sg + 1.
- Bit 0 set: this is a chain entry, the next real entry is at ->page_link
  with the two low bits masked off.
- Bit 1 set: this is the final entry in the sg entry. sg_next() will return
  NULL when passed such an entry.

It's thus important that sg table users use the proper accessors to get
and set the page member.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

The old __address element in struct scatterlist remained from older
kernels because the ARM DMA emulation code made use of it.  Move
this field into struct dma_struct, and convert DMA emulation code
to setup a SG entry as required.

Also, convert DMA emulation code to use the new DMA API rather
than the PCI DMA API.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!