Commit Graph

4145 Commits

Author SHA1 Message Date
Paul Mackerras 11a55f2274 Merge branch 'powerpc-next' of master.kernel.org:/pub/scm/linux/kernel/git/galak/powerpc 2008-04-18 13:34:30 +10:00
Paul Mackerras 858c52d15f Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/jk/spufs 2008-04-18 13:33:43 +10:00
Anton Vorontsov 1a9ebc0cd2 [POWERPC] 83xx: mpc8315 - fix USB UTMI Host setup
Currently USB Host isn't functional on the MPC8315E boards, for two
reasons as described below.

MPC8315 Reference Manual says:
"The USB DR unit must have the same clock ratio as the encryption core
unit, unless one of them has its clock disabled."

The encryption core also drives I2C clock, so it is enabled and is equal
to 01. That means USBDRCM should be 01 here.

Plus, according to MPC8315E-RDB schematics, USB unit consumes CLK_IN
clock from the 24.00MHz oscillator, which means we must adjust REFSEL
bits as well.

p.s.
Idially we should rework whole 83xx/usb.c code, in two steps:
1. Move SCCR code to the U-Boot;
2. Implement fsl,usb-clock property in the device tree, so usb.c could
   decide what clock exactly to use on per-board basis.

Though, today we're not in a hurry since there is just one 8315e board
out there.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 09:52:50 -05:00
Haiying Wang 8bdf573334 [POWERPC] 85xx: Fix the size of qe muram for MPC8568E
MPC8568E has 64K byte MURAM, so the size should be 0x10000, not 0xc000.

Signed-off-by: Haiying Wang <Haiying.Wang@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 09:52:18 -05:00
Paul Gortmaker 16787b430d [POWERPC] 86xx: mpc86xx_hpcn - Temporarily accept old dts node identifier.
As suggested by Timur Tabi, we match on the old compat node ID for one
version and warn accordingly.  If we don't do this, we plunge people who
try to use an old DTB into silent boot death with no clear indication of
what the problem is.

This patch should be removed at the beginning of the 2.6.27 dev cycle.
It is only meant to ease the transition in the short term.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 09:51:59 -05:00
Paul Gortmaker 06f35b4ba6 [POWERPC] 86xx: mark functions static, other minor cleanups
Cleanups as suggested by Stephen Rothwell and Dale Farnsworth, which
incudes marking a bunch of functions static and add a vendor prefix to
the compat node check for uniqueness.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 09:51:29 -05:00
Timur Tabi 3a2f020c5a [POWERPC] Make rheap safe for spinlocks
The rheap allocation function, rh_alloc, could call kmalloc with GFP_KERNEL.
This can sleep, which means you couldn't hold a spinlock while called rh_alloc.
Change all kmalloc calls to use GFP_ATOMIC so that it won't sleep.  This is
safe because only small blocks are allocated.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 09:50:38 -05:00
Kumar Gala 998c610363 [POWERPC] fsl: Convert dts to v1 syntax
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 09:40:48 -05:00
Kumar Gala 280bb34bc0 [POWERPC] 85xx: minor .dts cleanups
* remove #cpus from mpc8544ds.dts (not used anywhere else)
* remove memreserve from mpc8568mds.dts (not needed)

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:29:14 -05:00
Kumar Gala 32f960e943 [POWERPC] 85xx: Convert dts to v1 syntax
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:28:15 -05:00
Kumar Gala a5dc66e2ab [POWERPC] 85xx: Fix compile warning
arch/powerpc/platforms/85xx/mpc85xx_ads.c: In function ‘init_ioports’:
arch/powerpc/platforms/85xx/mpc85xx_ads.c:168: warning: initialization discards qualifiers from pointer target type

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:41 -05:00
Kumar Gala f9b9908cf9 [POWERPC] 83xx: Enable FCM NAND and OF partitions in defconfig
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:41 -05:00
Paul Gortmaker 81fad217b3 [POWERPC] 86xx: Add device tree source for Wind River SBC8641D
This adds in the device tree source for the SBC8641D, based
largely on the mpc8641_hpcn.dts.  The biggest differences are
the lack of a complex IRQ mapping (since no Uli/i8259 cascade)
and the different layout of devices on the localbus node.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:41 -05:00
Paul Gortmaker 1c37dca5e3 [POWERPC] 86xx: Add defconfig for Wind River SBC8641D board
This adds a sample defconfig for the Wind River SBC8641D
board, with SMP, PCI and NFS root enabled.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:41 -05:00
Paul Gortmaker 4e8aae89a3 [POWERPC] 86xx: Add support for Wind River SBC8641D board
This adds support for the Wind River SBC8641D board, based
largely on the mpc86xx_hpcn support.  The biggest difference is
the lack of the Uli and the i8259 cascade, which simplifies things.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:40 -05:00
Scott Wood 1e31de7aae [POWERPC] 83xx: mpc8313erdb - Enable FCM NAND and OF partitions in defconfig
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:40 -05:00
Scott Wood 378458d865 [POWERPC] cuboot-pq2: PCI fixes
1. Detect (and bail out on) more conditions that violate the
assumptions of the setup code -- we assume in such cases that the device
tree is correct and reflects what the firmware did.

2. The inbound memory mask calculation was wrong.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:40 -05:00
Scott Wood 3866409541 [POWERPC] fsl_soc: Factor fsl_get_sys_freq() out of the wdt and spi inits.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:40 -05:00
Anton Vorontsov 9c432797d3 [POWERPC] 83xx: mpc837x_rdb: add simple-bus compatible matching
This is needed to probe nor and nand flashes on the localbus.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:40 -05:00
Kumar Gala 4eaddb4d7e [POWERPC] Make Book-E debug handling SMP safe
global_dbcr0 needs to be a per cpu set of save areas instead of a single
global on all processors.

Also, we switch to using DBCR0_IDM to determine if the user space app is
being debugged as its a more consistent way.  In the future we should
support features like hardware breakpoint and watchpoints which will
have DBCR0_IDM set but not necessarily DBCR0_IC (single step).

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:40 -05:00
Scott Wood 3dd82a1ea7 [POWERPC] CPM: Always use new binding.
The kconfig entry can go away once arch/ppc and references to the config in
drivers are removed.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:40 -05:00
Anton Vorontsov 632395e19c [POWERPC] QE: fix sparse warnings
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:39 -05:00
Anton Vorontsov 7f0a6fc812 [POWERPC] QE: export qe_get_brg_clk()
qe_get_brg_clk() will be used by the fsl_gtm routines.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:39 -05:00
Anton Vorontsov 0b51b02edf [POWERPC] QE: implement qe_muram_offset
qe_muram_offset is the reverse of the qe_muram_addr, will be
used for the Freescale QE USB Host Controller driver.

This patch also moves qe_muram_addr into the qe.h header, plus
adds __iomem hints to use with sparse.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:39 -05:00
Anton Vorontsov acaa7aa30a [POWERPC] fsl_lbc: implement few UPM routines
Freescale UPM can be used to adjust localbus timings or to generate
orbitrary, pre-programmed "patterns" on the external Localbus signals.
This patch implements few routines so drivers could work with UPMs in
safe and generic manner.

So far there is just one user of these routines: Freescale UPM NAND
driver.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:38 -05:00
Anton Vorontsov 56626f335b [POWERPC] QE: UCC nodes cleanup
- get rid of `model = "UCC"' in the ucc nodes
  It isn't used anywhere, so remove it. If we'll ever need something
  like this, we'll use compatible property instead.
- replace last occurrences of device-id with cell-index.
  Drivers are modified for backward compatibility's sake.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:38 -05:00
Laurent Pinchart 872a15deed [POWERPC] CPM2: Reset the CPM when early debugging is not enabled.
Similarly to what is done for PQ1-based platforms, this patch resets the
PQ2 Communication Processor Module in cpm2_reset() when early debugging is
not enabled. This helps avoiding conflicts when the boot loader configured
the CPM in an unexpected way.

Signed-off-by: Laurent Pinchart <laurentp@cse-semaphore.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:37 -05:00
Laurent Pinchart 0585fa5fb7 [POWERPC] ep8248e: Reference SMC parameter RAM base in the device tree.
This patch modifies the Embedded Planet EP8248E device tree to reference the
SMC paramater RAM base register instead of the parameter RAM allocated by the
boot loader.

The cpm_uart driver will allocate parameter RAM itself, making the serial port
initialisation independent of the boot loader.

The patch adds the parameter RAM allocated by the boot loader in the CPM muram
node, making it available to the kernel.

Signed-off-by: Laurent Pinchart <laurentp@cse-semaphore.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:37 -05:00
Laurent Pinchart c2dd3529f3 [POWERPC] cpm-serial: Relocate CPM buffer descriptors and SMC parameter ram.
This patch relocates the buffer descriptors and the SMC parameter RAM at the
end of the first CPM muram chunk, as described in the device tree. This allows
device trees to stop excluding SMC parameter ram allocated by the boot loader
from the CPM muram node.

Signed-off-by: Laurent Pinchart <laurentp@cse-semaphore.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:37 -05:00
Laurent Pinchart da0a5f0c65 [POWERPC] Add bootwrapper function to get virtual reg from the device tree.
This patch adds a new generic device tree processing function that retrieves
virtual reg addresses from the device tree to the bootwrapper code. It also
updates the bootwrapper code to use the new function.

dt_get_virtual_reg() retrieves the virtual reg addresses from the
"virtual-reg" property. If the property can't be found, it uses the "reg"
property and walks the tree to translate it to absolute addresses.

Signed-off-by: Laurent Pinchart <laurentp@cse-semaphore.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:37 -05:00
Sebastian Siewior 1028d4f162 [POWERPC] 85xx: Enable DMA engine on the MPC8544 DS
Add the device tree node for the DMA engine on 8544, publish
the device and enable the driver in the defconfig.

Signed-off-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:36 -05:00
Kumar Gala 370131c3f2 [POWERPC] 83xx/85xx: Reorganize defconfigs
Board specific defconfigs are useful, however with the ability to do
multi-board defconfigs they aren't needed in the top level configs directory

Move the 83xx/85xx board specific defconfigs to individual directories under
arch/powerpc/configs.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:36 -05:00
Kumar Gala eb0cd5fd29 [POWERPC] Rework Book-E debug exception handling
The architecture allows for "Book-E" style debug interrupts to either go
to critial interrupts of their own debug interrupt level.  To allow for
a dynamic kernel to support machines of either type we want to be able to
compile in the interrupt handling code for both exception levels.

Towards this goal we renamed the debug handling macros to specify the
interrupt level in their name (DEBUG_CRIT_EXCEPTION/DebugCrit and
DEBUG_DEBUG_EXCEPTION/DebugDebug).

Additionally, on the Freescale Book-e parts we expanded the exception
stacks to cover the maximum case of needing three exception stacks (normal,
machine check and debug).

There is some kernel text space optimization to be gained if a kernel is
configured for a specific Freescale implementation but we aren't handling
that now to allow for the single kernel image support.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-04-17 01:01:36 -05:00
Kumar Gala 7711684947 [POWERPC] Remove unused machine call outs
When we moved to arch/powerpc we actively tried to avoid using the
ppc_md.setup_io_mappings().  Currently no board ports use it so let's
remove it to avoid any new boards using it.

Also, remove early_serial_map() since we don't even have a call out for
it in arch/powerpc.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 10:01:00 +10:00
Michael Ellerman 5faae2e5d1 [POWERPC] Always add preferred consoles in platforms/pseries/lpar.c
There is logic in platforms/peries/lpars.c which checks if the user has
specified a console on the command line, and refrains from adding a
preferred console entry for the hvc/hvsi console if they have.

This trips up if you use "netconsole=foo" on the command line, and has
the result that you get _only_ the netconsole, because the hvc device is
never added as a preferred console. Worse still if you get the netconsole
configuration wrong somehow, you end up with no console at all.

As it turns out we don't need to worry about checking the command line.
If the user has specified "console=foo", then foo will be set as the
preferred console when the command line is parsed in start_kernel(), much
later than the pseries code, and so the latter setting will take effect.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 10:00:59 +10:00
Michael Ellerman 21cf91338f [POWERPC] Move prototype for find_udbg_vterm() into a header file
Move the prototype for find_udbg_vterm() into pseries.h, removing
it from setup.c.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 10:00:59 +10:00
Manish Ahuja 37ddd5d053 [POWERPC] pseries/phyp dump: Reserve a variable amount of space at boot
This changes the way we calculate how much space to reserve for the
pHyp dump.  Currently we reserve 256MB only.  With this change, the
code first checks to see if an amount has been specified on the boot
command line with the "phyp_dump_reserve_size" option, and if so, uses
that much.

Otherwise it computes 5% of total ram and rounds it down to a multiple
of 256MB, and uses the larger of that or 256MB.

This is for large systems with a lot of memory (10GB or more).  The
aim is to have more space available for the kernel on reboot on
machines with more resources.  Although the dump will be collected
pretty fast and the memory released really early on allowing the
machine to have the full memory available, this alleviates any issues
that can be caused by having way too little memory on very very large
systems during those few minutes.

Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:14 +10:00
Kumar Gala b18796d32a [POWERPC] bootwrapper: Use physical address in PHDR for uImage
Now that we properly set the physical address in the program header of the
vmlinux ELF we can extract it to properly set the load and entry point for
u-boot uImages.  Before we always hard coded the load & entry point to 0.
However there are situations that the kernel may be built with a non-zero
physical address.

We use objdump to extract the PHDR.  We assume that there is only one
PHDR in the vmlinux of type LOAD.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:14 +10:00
Kumar Gala 366234f657 [POWERPC] Update linker script to properly set physical addresses
We can set LOAD_OFFSET and use the AT attribute on sections and the
linker will properly set the physical address of the LOAD program
header for us.

This allows us to know how the PHYSICAL_START the user configured a
kernel with by just looking at the resulting vmlinux ELF.

This is pretty much stolen from how x86 does things in their linker
scripts.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:14 +10:00
Kumar Gala 4846c5deb9 [POWERPC] Clean up some linker and symbol usage
* PAGE_OFFSET is not always the start of code, use _stext instead.
* grab PAGE_SIZE and KERNELBASE from asm/page.h like ppc64 does.  Makes the
  code a bit more common and provide a single place to manipulate the
  defines for things like kdump.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:13 +10:00
Kumar Gala 09b5e63f82 [POWERPC] Rename __initial_memory_limit to __initial_memory_limit_addr
We always use __initial_memory_limit as an address so rename it
to be clear.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:13 +10:00
Kumar Gala 0aef996b37 [POWERPC] 85xx: Cleanup TLB initialization
* Determine the RPN we are running the kernel at runtime rather
  than using compile time constant for initial TLB

* Cleanup adjust_total_lowmem() to respect memstart_addr and
  be a bit more clear on variables that are sizes vs addresses.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:13 +10:00
Kumar Gala d7917ba705 [POWERPC] Introduce lowmem_end_addr to distinguish from total_lowmem
total_lowmem represents the amount of low memory, not the physical
address that low memory ends at.  If the start of memory is at 0 it
happens that total_lowmem can be used as both the size and the address
that lowmem ends at (or more specifically one byte beyond the end).

To make the code a bit more clear and deal with the case when the start of
memory isn't at physical 0, we introduce lowmem_end_addr that represents
one byte beyond the last physical address in the lowmem region.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:13 +10:00
Kumar Gala 99c62dd773 [POWERPC] Remove and replace uses of PPC_MEMSTART with memstart_addr
A number of users of PPC_MEMSTART (40x, ppc_mmu_32) can just always
use 0 as we don't support booting these kernels at non-zero physical
addresses since their exception vectors must be at 0 (or 0xfffx_xxxx).

For the sub-arches that support relocatable interrupt vectors
(book-e), it's reasonable to have memory start at a non-zero physical
address.  For those cases use the variable memstart_addr instead of
the #define PPC_MEMSTART since the only uses of PPC_MEMSTART are for
initialization and in the future we can set memstart_addr at runtime
to have a relocatable kernel.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:12 +10:00
Kumar Gala 1993cbf4ae [POWERPC] Provide access to arch/powerpc include path on ppc64
There does not appear to be any reason that we shouldn't just have
-Iarch/$(ARCH) on both ppc32 and ppc64 builds.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:12 +10:00
Kumar Gala 38521a23a9 [POWERPC] Remove Kconfig option BOOT_LOAD
Nothing appears to use BOOT_LOAD so remove it as a configurable option.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:12 +10:00
Adrian Bunk 3fbe9d413e [POWERPC] Add MODULE_LICENSE to powerpc/sysdev/rtc_cmos_setup.c
This adds the missing MODULE_LICENSE("GPL").

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:12 +10:00
David Woodhouse 7f4392cdcc [POWERPC] Efika: Really, don't pretend to be CHRP
Fedora 9 works on Efika without the separate 'device-tree supplement',
thanks to the kernel's own fixups. With one exception -- because 'CHRP'
still appears on the 'machine:' line in /proc/cpuinfo, the installer
misdetects the platform and misconfigures yaboot, putting it into a PReP
boot partition instead of in the /boot filesystem where the Efika's
firmware could find it.

The kernel's fixups for Efika already correct one instance of 'chrp', in
the 'device_type' property. This fixes it in the 'CODEGEN,description'
property too, since that's what's exposed to userspace in /proc/cpuinfo.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:12 +10:00
Anton Vorontsov b7ce341585 [POWERPC] Implement support for the GPIO LIB API
This implements support for the GPIO LIB API.  Two calls are still
unimplemented though: irq_to_gpio and gpio_to_irq.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:11 +10:00
Benjamin Herrenschmidt e6768a4f39 [POWERPC] Fixup softirq preempt count
This fixes the handling of the preempt count when switching
interrupt stacks so that HW interrupt properly get the softirq
mask copied over from the previous stack.

It also initializes the softirq stack preempt_count to 0 instead
of SOFTIRQ_OFFSET, like x86, as __do_softirq() does the increment,
and we hit some lockdep checks if we have it twice.

That means we do run for a little while off the softirq stack
with the preempt-count set to 0, which could be deadly if we
try to take a softirq at that point, however we do so with
interrupts disabled, so I think we are ok.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-17 07:46:11 +10:00