linux.git/arch/arc, branch v4.19-rc4

ARC: don't check for HIGHMEM pages in arch_dma_alloc

2018-09-04T20:21:38+00:00

__GFP_HIGHMEM flag is cleared by upper layer functions
(in include/linux/dma-mapping.h) so we'll never get a
__GFP_HIGHMEM flag in arch_dma_alloc gfp argument.
That's why alloc_pages will never return highmem page
here.

Get rid of highmem pages handling and cleanup arch_dma_alloc
and arch_dma_free functions.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta

ARC: IOC: panic if both IOC and ZONE_HIGHMEM enabled

2018-09-04T20:21:37+00:00

Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta

ARC: dma [IOC] Enable per device io coherency

2018-09-04T20:21:37+00:00

So far the IOC treatment was global on ARC, being turned on (or off)
for all devices in the system. With this patch, this can now be done
per device using the "dma-coherent" DT property; IOW with this patch
we can use both HW-coherent and regular DMA peripherals simultaneously.

The changes involved are too many so enlisting the summary below:

1. common code calls ARC arch_setup_dma_ops() per device.

2. For coherent dma (IOC) it plugs in generic @dma_direct_ops which
   doesn't need any arch specific backend: No need for any explicit
   cache flushes or MMU mappings to provide for uncached access

   - dma_(map|sync)_single* return early as corresponding dma ops callbacks
     are NULL in generic code.
     So arch_sync_dma_*() -> dma_cache_*() need not handle the coherent
     dma case, hence drop ARC __dma_cache_*_ioc() which were no-op anyways

3. For noncoherent dma (non IOC) generic @dma_noncoherent_ops is used
   which in turns calls ARC specific routines

   - arch_dma_alloc() no longer checks for @ioc_enable since this is
     called only for !IOC case.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta 
[vgupta: rewrote changelog]

ARC: dma [IOC]: mark DMA devices connected as dma-coherent

2018-08-31T19:47:26+00:00

Mark DMA devices on AXS103 and HSDK boards connected through IOC
port as dma-coherent.

Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta

ARC: atomics: unbork atomic_fetch_##op()

2018-08-31T17:14:51+00:00

In 4.19-rc1, Eugeniy reported weird boot and IO errors on ARC HSDK

| INFO: task syslogd:77 blocked for more than 10 seconds.
|       Not tainted 4.19.0-rc1-00007-gf213acea4e88 #40
| "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
| message.
| syslogd         D    0    77     76 0x00000000
|
| Stack Trace:
|  __switch_to+0x0/0xac
|  __schedule+0x1b2/0x730
|  io_schedule+0x5c/0xc0
|  __lock_page+0x98/0xdc
|  find_lock_entry+0x38/0x100
|  shmem_getpage_gfp.isra.3+0x82/0xbfc
|  shmem_fault+0x46/0x138
|  handle_mm_fault+0x5bc/0x924
|  do_page_fault+0x100/0x2b8
|  ret_from_exception+0x0/0x8

He bisected to 84c6591103db ("locking/atomics,
asm-generic/bitops/lock.h: Rewrite using atomic_fetch_*()")

This commit however only unmasked the real issue introduced by commit
4aef66c8ae9 ("locking/atomic, arch/arc: Fix build") which missed the
retry-if-scond-failed branch in atomic_fetch_##op() macros.

The bisected commit started using atomic_fetch_##op() macros for building
the rest of atomics.

Fixes: 4aef66c8ae9 ("locking/atomic, arch/arc: Fix build")
Reported-by: Eugeniy Paltsev 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Will Deacon 
Signed-off-by: Vineet Gupta 
[vgupta: wrote changelog]

arc: remove redundant GCC version checks

2018-08-31T00:51:44+00:00

Commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6")
bumped the minimum GCC version to 4.6 for all architectures.

With GCC >= 4.6 assumed, 'upto_gcc44' is empty, 'atleast_gcc44' is y.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Vineet Gupta

ARC: sort Kconfig

2018-08-27T16:00:36+00:00

Signed-off-by: Vineet Gupta

ARC: cleanup show_faulting_vma()

2018-08-27T16:00:36+00:00

 - Remove unused variables
 - check return value of file_path

Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta

ARC: [plat-axs*]: Enable SWAP

2018-08-27T16:00:36+00:00

SWAP support on ARC was fixed earlier by
commit 6e3761145a9b ("ARC: Fix CONFIG_SWAP")
so now we may safely enable it on platforms that
have external media like USB and SD-card.

Note: it was already allowed for HSDK

Signed-off-by: Alexey Brodkin 
Cc: stable@vger.kernel.org # 6e3761145a9b: ARC: Fix CONFIG_SWAP
Signed-off-by: Vineet Gupta

ARC: [plat-axs*/plat-hsdk]: Allow U-Boot to pass MAC-address to the kernel

2018-08-27T16:00:36+00:00

Otherwise kernel uses random MAC which is not very conveniet.
With that change in place use might set desired MAC in U-Boot
with "setenv ethaddr 11:22:33:44:55:66", save environment and
then from boot to boot the same MAC will be used by the kernel.

One other note for this to happen it's required to pass
board's .dtb in U-Boot's "bootm" command like that:
------------------->8-----------------
bootm 0x82000000 - 0x84000000
------------------->8-----------------

Here 0x82000000 is location of uImage while
0x80000000 is location of either axs10x.dtb or hsdk.dtb
previously loaded from SD-card, USB storage or TFTP server.

Signed-off-by: Alexey Brodkin 
Cc: Rob Herring 
Cc: stable@vger.kernel.org # 4.14
Cc: devicetree@vger.kernel.org
Signed-off-by: Vineet Gupta