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931db7d688
kernel-ark/include/asm-arm
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Lennert Buytenhek 931db7d688 [ARM] 3050/1: remove ixp2000_reg_write erratum #66 workaround 
Patch from Lennert Buytenhek

The workaround that we do for avoiding triggering ixp2400 erratum #66
involves mapping I/O pages using XCB=101 instead of XCB=000 so that we
prevent the I/O signal to the gasket from being asserted (which can
cause data corruption.)  But XCB=101 mappings are write-buffered while
mappings using XCB=000 are not, which is why if we use XCB=101 mappings
we do a readback for every CSR store in an attempt to make sure that
the store has been pushed out of the xscale core and the gasket.

Unfortunately, there are two issues with this:
- we do a readback for every CSR store, which is wrong, because the
  register we are writing to might have unwanted side-effects on read,
  for example, in the case of the scratchpad ring enqueue/dequeue
  registers; and
- the readback is totally ineffective in the way we currently do it,
  because we just issue a load but do not issue any instruction that
  depends on the return value of that load, so the xscale core does
  not wait for the load to complete before continuing.

See this linux-arm-kernel mailing list post for further information:
	http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2005-September/031314.html

This means that my ixp2400 boxes have been running for many months
without a working readback in ixp2000_reg_write, without any apparent
adverse effects.  Two of them have been running for a week now with
the actual readback deleted from ixp2000_reg_write, also without any
apparent ill effects.

So, because in its current form it does more harm than good, the
readback in ixp2000_reg_write should simply be killed, as the patch
below does.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-29 16:28:26 +01:00
..
arch-aaec2000 [ARM] 3041/1: AAEC-2000 - CLCD controller platform glue 2005-10-28 16:51:44 +01:00
arch-cl7500 [ARM] 1/4: Move include of asm/hardware.h to asm-arm/arch-*/io.h 2005-10-28 10:20:25 +01:00
arch-clps711x [ARM] 2918/1: [update] Base port of Comdial MP1000 platfrom 2005-10-28 16:19:37 +01:00
arch-ebsa110 [ARM] 2/4: Remove asm/hardware.h from asm-arm/arch-ebsa110/io.h 2005-10-28 10:29:21 +01:00
arch-ebsa285 [ARM] 1/4: Move include of asm/hardware.h to asm-arm/arch-*/io.h 2005-10-28 10:20:25 +01:00
arch-epxa10db [ARM] 1/4: Move include of asm/hardware.h to asm-arm/arch-*/io.h 2005-10-28 10:20:25 +01:00
arch-h720x [ARM] 1/4: Move include of asm/hardware.h to asm-arm/arch-*/io.h 2005-10-28 10:20:25 +01:00
arch-imx [ARM] 1/4: Move include of asm/hardware.h to asm-arm/arch-*/io.h 2005-10-28 10:20:25 +01:00
arch-integrator [ARM] 3/4: Remove asm/hardware.h from Versatile and Integrator io.h 2005-10-28 14:05:16 +01:00
arch-iop3xx [ARM] 1/4: Move include of asm/hardware.h to asm-arm/arch-*/io.h 2005-10-28 10:20:25 +01:00
arch-ixp4xx [ARM] 3021/1: Interrupt 0 bug fix for ixp4xx 2005-10-18 07:53:35 +01:00
arch-ixp2000 [ARM] 3050/1: remove ixp2000_reg_write erratum #66 workaround 2005-10-29 16:28:26 +01:00
arch-l7200 [ARM] 1/4: Move include of asm/hardware.h to asm-arm/arch-*/io.h 2005-10-28 10:20:25 +01:00
arch-lh7a40x [ARM] 1/4: Move include of asm/hardware.h to asm-arm/arch-*/io.h 2005-10-28 10:20:25 +01:00
arch-omap [ARM] 1/4: Move include of asm/hardware.h to asm-arm/arch-*/io.h 2005-10-28 10:20:25 +01:00
arch-pxa [ARM] 2897/2: PXA2xx IRDA support 2005-10-28 16:39:33 +01:00
arch-rpc [ARM] 1/4: Move include of asm/hardware.h to asm-arm/arch-*/io.h 2005-10-28 10:20:25 +01:00
arch-s3c2410 [ARM] 3045/2: S3C2410 - change init for lcd platform data 2005-10-28 15:31:45 +01:00
arch-sa1100 [ARM] 3/4: Remove asm/hardware.h from SA1100 io.h 2005-10-28 14:25:28 +01:00
arch-shark [ARM] 1/4: Move include of asm/hardware.h to asm-arm/arch-*/io.h 2005-10-28 10:20:25 +01:00
arch-versatile [ARM] 3/4: Remove asm/hardware.h from Versatile and Integrator io.h 2005-10-28 14:05:16 +01:00
hardware [ARM] 2962/1: scoop: Allow GPIO pin suspend state to be specified 2005-10-10 10:20:06 +01:00
mach [ARM] Allow MTD device name to be passed via platform data 2005-10-29 16:08:31 +01:00
a.out.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
apm.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
assembler.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
atomic.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
auxvec.h [PATCH] auxiliary vector cleanups 2005-09-07 16:57:21 -07:00
bitops.h [ARM] 3032/1: sparse: complains about generic_fls() prototype in asm-arm/bitops.h 2005-10-26 15:04:21 +01:00
bug.h [PATCH] qualifiers in return types - easy cases 2005-08-23 18:43:45 -07:00
bugs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
byteorder.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cache.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cacheflush.h [ARM] Fix ARMv6 VIPT cache >= 32K 2005-09-08 15:32:23 +01:00
checksum.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cpu-multi32.h [PATCH] qualifiers in return types - easy cases 2005-08-23 18:43:45 -07:00
cpu-single.h [PATCH] qualifiers in return types - easy cases 2005-08-23 18:43:45 -07:00
cpu.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cputime.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
current.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
delay.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
div64.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
dma-mapping.h [PATCH] gfp_t: dma-mapping (arm) 2005-10-28 08:16:47 -07:00
dma.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
domain.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ecard.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
elf.h [ARM] 2941/1: Fix running legacy binaries from a soft-float root filesystem with CONFIG_IWMMXT. 2005-09-30 00:17:35 +01:00
emergency-restart.h [PATCH] Add emergency_restart() 2005-07-26 14:35:41 -07:00
errno.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
fcntl.h [PATCH] Clean up struct flock64 definitions 2005-09-07 16:57:38 -07:00
fiq.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
floppy.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
fpstate.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
futex.h [ARM] Fix warning in asm/futex.h 2005-09-18 21:11:08 +01:00
glue.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
hardirq.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
hardware.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ide.h [PATCH] ARM: 2758/1: Fix comment in file header to read "ARM" instead i386 2005-06-27 15:58:39 +01:00
io.h [ARM] 1/4: Move include of asm/hardware.h to asm-arm/arch-*/io.h 2005-10-28 10:20:25 +01:00
ioctl.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ioctls.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ipc.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ipcbuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
irq.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
kmap_types.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
leds.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
limits.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
linkage.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
local.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
locks.h [ARM] 3019/1: fix wrong comments 2005-10-18 07:51:34 +01:00
mc146818rtc.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
memory.h [ARM] Tighten pfn_valid() test. 2005-09-15 15:17:59 +01:00
mman.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mmu_context.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mmu.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mmzone.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
module.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
msgbuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mtd-xip.h [MTD] XIP cleanup 2005-07-07 16:50:16 +02:00
namei.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
numnodes.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
nwflash.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
page.h [PATCH] mm: consolidate get_order 2005-09-05 00:05:39 -07:00
param.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
parport.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pci.h [PATCH] Make sparc64 use setup-res.c 2005-09-08 14:57:25 -07:00
percpu.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pgalloc.h [PATCH] ARM: Factor out common pmd_populate functionality 2005-06-22 20:58:29 +01:00
pgtable.h [PATCH] feature removal of io_remap_page_range() 2005-09-13 08:22:33 -07:00
poll.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
posix_types.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
proc-fns.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
processor.h [PATCH] ARM: Fix kernel stack offset calculations 2005-05-05 13:11:00 +01:00
procinfo.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ptrace.h [PATCH] ARM: showregs 2005-04-17 15:50:36 +01:00
resource.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
rtc.h [PATCH] ARM: RTC: allow driver methods to return error 2005-04-30 12:19:28 +01:00
scatterlist.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sections.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
segment.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
semaphore-helper.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
semaphore.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sembuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
serial.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
setup.h [ARM] 2925/3: earlyparam - postfix section with .init for make buildcheck 2005-09-20 16:25:12 +01:00
shmbuf.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
shmparam.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sigcontext.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
siginfo.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
signal.h [ARM] Remove SA_IRQNOMASK 2005-09-26 15:30:20 +01:00
sizes.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
smp.h [PATCH] ARM SMP: Rename cpu_present_mask to cpu_possible_map 2005-07-11 17:38:36 +01:00
socket.h [NET]: Introduce SO_{SND,RCV}BUFFORCE socket options 2005-08-29 15:31:35 -07:00
sockios.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
spinlock_types.h [PATCH] spinlock consolidation 2005-09-10 10:06:21 -07:00
spinlock.h [PATCH] spinlock consolidation 2005-09-10 10:06:21 -07:00
stat.h [PATCH] ARM: Fix new-ABI layout of struct stat64 2005-07-04 13:02:46 +01:00
statfs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
string.h [PATCH] ARM: 2653/1: Fix memset and memzero macro double-reference of parameters 2005-04-25 23:40:05 +01:00
suspend.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
system.h [PATCH] ARM SMP: Add ARMv6 memory barriers 2005-07-26 19:44:26 +01:00
termbits.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
termios.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
therm.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
thread_info.h [PATCH] streamline preempt_count type across archs 2005-06-23 09:45:19 -07:00
timex.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
tlb.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
tlbflush.h [PATCH] ARM SMP: TLB implementations only affect local CPU 2005-06-28 13:40:39 +01:00
topology.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
traps.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
types.h [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
uaccess.h [PATCH] remove verify_area(): remove verify_area() from various uaccess.h headers 2005-09-07 16:57:35 -07:00
ucontext.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
unaligned.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
unistd.h [ARM] Add memory type based allocation syscalls 2005-09-09 11:12:51 +01:00
user.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
vfp.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
vfpmacros.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
vga.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
xor.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00