Recent U-Boot commit 5ccd29c3679b3669b0bde5c501c1aa0f325a7acb caused
the "cpu-release-addr" device tree property to contain the physical RAM
location that secondary cores were spinning at.  Previously, the
"cpu-release-addr" property contained a value referencing the boot page
translation address range of 0xfffffxxx, which then indirectly accessed
RAM.

The "cpu-release-addr" is currently ioremapped and the secondary cores
kicked.  However, due to the recent change in "cpu-release-addr", it
sometimes points to a memory location in low memory that cannot be
ioremapped.  For example on a P2020-based board with 512MB of RAM the
following error occurs on bootup:

  <...>
  mpic: requesting IPIs ...
  __ioremap(): phys addr 0x1ffff000 is RAM lr c05df9a0
  Unable to handle kernel paging request for data at address 0x00000014
  Faulting instruction address: 0xc05df9b0
  Oops: Kernel access of bad area, sig: 11 [#1]
  SMP NR_CPUS=2 P2020 RDB
  Modules linked in:
  <... eventual kernel panic>

Adding logic to conditionally ioremap or access memory directly resolves
the issue.
Signed-off-by: NPeter Tyser <ptyser@xes-inc.com>
Signed-off-by: NNate Case <ncase@xes-inc.com>
Reported-by: NDipen Dudhat <B09055@freescale.com>
Tested-by: NDipen Dudhat <B09055@freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

The following commit introduced a compile error since it removed
the implementation of smp_85xx_basic_setup:

commit 77c0a700
Author: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date:   Fri Aug 28 14:25:04 2009 +1000

    powerpc: Properly start decrementer on BookE secondary CPUs

Make it so that smp_ops probe() and setup_cpu() can be set to NULL.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This moves the code to start the decrementer on 40x and BookE into
a separate function which is now called from time_init() and
secondary_time_init(), before the respective clock sources are
registered. We also remove the 85xx specific code for doing it
from the platform code.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Those definitions are currently declared extern in the .c file where
they are used, move them to a header file instead.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

lockdep trace found the following:

------------[ cut here ]------------
Badness at c007baf0 [verbose debug info unavailable]
NIP: c007baf0 LR: c007bad8 CTR: 00000000
REGS: ef855e00 TRAP: 0700   Tainted: G        W
(2.6.30-06736-g12a31df-dirty)
MSR: 00021000 <ME,CE>  CR: 24044022  XER: 20000000
TASK = ef858000[1] 'swapper' THREAD: ef854000 CPU: 0
GPR00: 00000000 ef855eb0 ef858000 00000001 000000d0 f1000000 ffbc8000 ffffffff
GPR08: 000000d0 c0760000 c0710000 00000007 2fffffff 1004a388 7ffd9400 00000000
GPR16: 00000000 7ffcd100 7ffcd100 7ffcd100 c059cd78 c075c498 c057da7c ffffffff
GPR24: ffbc8000 f1000000 00000001 c00bf8b0 c07595d4 000000d0 00021000 000000d0
NIP [c007baf0] lockdep_trace_alloc+0xc0/0xf0
LR [c007bad8] lockdep_trace_alloc+0xa8/0xf0
Call Trace:
[ef855eb0] [c007ba60] lockdep_trace_alloc+0x30/0xf0 (unreliable)
[ef855ec0] [c00cb3ac] kmem_cache_alloc+0x2c/0xf0
[ef855ee0] [c00bf8b0] __get_vm_area_node+0x80/0x1c0
[ef855f10] [c0017580] __ioremap_caller+0x1d0/0x1e0
[ef855f40] [c057da7c] smp_85xx_kick_cpu+0x64/0x124
[ef855f60] [c0599180] __cpu_up+0xd0/0x1a4
[ef855f80] [c05997c4] cpu_up+0x14c/0x1e0
[ef855fc0] [c05732a0] kernel_init+0x100/0x1c4
[ef855ff0] [c0011524] kernel_thread+0x4c/0x68
Instruction dump:
8009c174 2f800000 409e0048 73c08000 40820040 4818980d 2f830000 419effa0
3d20c076 8009c388 2f800000 409eff90 <0fe00000> 4bffff88 60000000 60000000

We were calling ioremap after we local_irq_restore(flags).  A simple
reorder fixes the problem.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

Use device tree to determine if we actually have an MPIC and use
CPU feature to decide if we should use doorbells for IPIs.
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

There is a call to local_irq_restore in the normal exit case, so it would
seem that there should be one on an error return as well.

The semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression l;
expression E,E1,E2;
@@

local_irq_save(l);
... when != local_irq_restore(l)
    when != spin_unlock_irqrestore(E,l)
    when any
    when strict
(
if (...) { ... when != local_irq_restore(l)
               when != spin_unlock_irqrestore(E1,l)
+   local_irq_restore(l);
    return ...;
}
|
if (...)
+   {local_irq_restore(l);
    return ...;
+   }
|
spin_unlock_irqrestore(E2,l);
|
local_irq_restore(l);
)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

Added 85xx specifc smp_ops structure.  We use ePAPR style boot release
and the MPIC for IPIs at this point.

Additionally added routines for secondary cpu entry and initializtion.
Signed-off-by: NAndy Fleming <afleming@freescale.com>
Signed-off-by: NTrent Piepho <tpiepho@freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>