Read the core ID in bmips_smp_finish() for BMIPS5000 CPUs to get appropriate
processor parenting in set_cpu_sibling_map().
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Cc: john@phrozen.org
Cc: cernekee@gmail.com
Cc: jon.fraser@broadcom.com
Cc: jaedon.shin@gmail.com
Cc: dragan.stancevic@gmail.com
Cc: jogo@openwrt.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12380/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The majority of SMP platforms handle their IPIs through do_IRQ()
which calls irq_{enter/exit}(). When a call function IPI is received,
smp_call_function_interrupt() is called which also calls
irq_{enter,exit}(), meaning irq_count is raised twice.

When tick broadcasting is used (which is implemented via a call
function IPI), this incorrectly causes all CPU idle time on the core
receiving broadcast ticks to be accounted as time spent servicing
IRQs, as account_process_tick() will account as such if irq_count is
greater than 1. This results in 100% CPU usage being reported on a
core which receives its ticks via broadcast.

This patch removes the SMP smp_call_function_interrupt() wrapper which
calls irq_{enter,exit}(). Platforms which handle their IPIs through
do_IRQ() now call generic_smp_call_function_interrupt() directly to
avoid incrementing irq_count a second time. Platforms which don't
(loongson, sgi-ip27, sibyte) call generic_smp_call_function_interrupt()
wrapped in irq_{enter,exit}().
Signed-off-by: NAlex Smith <alex.smith@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10770/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

bmips_wr_vec() copies exception vector code from start to dst.

The call to dma_cache_wback() needs to flush (end-start) bytes,
starting at dst, from write-back cache to memory.
Signed-off-by: NPetri Gynther <pgynther@google.com>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: NKevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10193/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Thanks to spatch, plus manual removal of "&*".  Then a sweep for
for_each_cpu_mask => for_each_cpu.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-mips@linux-mips.org

On some chips like bcm3384, "other stuff" gets wired up to CPU1's IE_IRQ1
input, generating spurious IRQs.  In this case we want the platform code
to be able to mask it off.
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: mbizon@freebox.fr
Cc: jogo@openwrt.org
Cc: jfraser@broadcom.com
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8163/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The secondary CPU's reset vector needs to be set to KSEG1 for a cold
boot (release from reset), or KSEG0 for a warm restart.  On a cold boot
KSEG0 may be unavailable (BMIPS4380), and on a warm restart KSEG1 may
be unavailable (XKS01 mode on 4380 or 5000).
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: mbizon@freebox.fr
Cc: jogo@openwrt.org
Cc: jfraser@broadcom.com
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8161/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

CPU interrupts need to be disabled on a cpu being taken down.
When a cpu is hot-plugged out of the system the following sequence occurs.

On the CPU where the hotplug sequence was initiated:
    cpu_down
        _cpu_down {
            __cpu_notify(CPU_DOWN_PREPARE
            __stop_machine(take_cpu_down
                wait for cpu to run disable code.
            __cpu_die
        }

On the CPU  being disabled:
    take_cpu_down
        __cpu_disable {
            mp_ops->cpu_disable
                bmips_cpu_disable
                    clear_c0_status(IE_IRQ5) (added)
            cpu_notify(CPU_DYING...
        }

Before the cpu_notifier is called with CPU_DYING, all interrupts on the
dying cpu must be disabled.  This guarantees that before tick_notify is
called with the CPU_DYING event and sets the clock device pointer to
NULL, there can not be any more clock interrupts.

When this wasn't done, an unfortunately-timed timer interrupt sometimes
caused hangs immediately prior to system suspend:

    Debug PM is not enabled. To enable partial suspend, rebuild kernel with CONFIG_PM_DEBUG
    Pass 1 out of 1,PM: Syncing filesystems ... mode=none, tp1=done.
    1, flags=5, cycle_tp=, sleep=
    Freezing user space processes ... (elapsed 0.01 seconds) done.
    Freezing remaining freezable tasks ... (elapsed 0.01 seconds) done.
    PM: suspend of devices complete after 54.199 msecs
    PM: late suspend of devices complete after 0.172 msecs
    Disabling non-boot CPUs ...
    SMP: CPU1 is offline
    INFO: rcu_sched detected stalls on CPUs/tasks: { 3} (detected by 0, t=62537 jiffies)
    Call Trace:
    [<804baa78>] dump_stack+0x8/0x34
    [<8008a2d8>] __rcu_pending+0x4b8/0x55c
    [<8008adf4>] rcu_check_callbacks+0x78/0x180
    [<80037830>] update_process_times+0x40/0x6c
    [<80072fe4>] tick_sched_timer+0x74/0xe4
    [<80050180>] __run_hrtimer.clone.30+0x64/0x140
    [<80051150>] hrtimer_interrupt+0x19c/0x4bc
    [<8000cdb8>] c0_compare_interrupt+0x50/0x88
    [<80081b18>] handle_irq_event_percpu+0x5c/0x2f4
    [<80086490>] handle_percpu_irq+0x8c/0xc0
    [<800811b4>] generic_handle_irq+0x34/0x54
    [<800067dc>] do_IRQ+0x18/0x2c
    [<8000375c>] plat_irq_dispatch+0xd0/0x128
    [<80004a04>] ret_from_irq+0x0/0x4
    [<80004c40>] r4k_wait+0x20/0x40
    [<80006b6c>] cpu_idle+0x98/0xf0
    [<805d3988>] start_kernel+0x424/0x440
Signed-off-by: NJon Fraser <jfraser@broadcom.com>
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: mbizon@freebox.fr
Cc: jogo@openwrt.org
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8160/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

BMIPS3300 processors do not have the hardware to support SMP, but with a
small tweak, the SMP ebase relocation code allows BMIPS3300-based
platforms to reuse the S2/S3 power management code from BMIPS4380-based
chips.  Normally this is as simple as adding one line to prom_init():

    board_ebase_setup = &bmips_ebase_setup;
Signed-off-by: NJon Fraser <jfraser@broadcom.com>
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: mbizon@freebox.fr
Cc: jogo@openwrt.org
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8159/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This will need to be called from a few different places, and the logic
is starting to get a bit hairy (with the need for IPIs, CPU bug
workarounds, and hazards).
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: mbizon@freebox.fr
Cc: jogo@openwrt.org
Cc: jfraser@broadcom.com
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8158/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

On some older BMIPS5200 (dual core / quad thread) platforms, the
PROM code set up CPU2/CPU3 so they would be started through an NMI
instead of through the ACTION register.  But this was incompatible with
some power management features that were later added, so the scheme was
changed so that Linux is fully responsible for booting CPU2/CPU3.
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: mbizon@freebox.fr
Cc: jogo@openwrt.org
Cc: jfraser@broadcom.com
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8157/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.

The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e.  using a global
register that may be set to the per cpu base.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	__this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	__this_cpu_inc(y)

Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Nothing was using the method and there isn't any need for this hook.  This
leaves smp_cpus_done() empty for the moment.

As suggested by Paul Bolle <pebolle@tiscali.nl>.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Allow building for all bmips cpus at the same time by changing ifdefs
to checks for the cpu type, or adding appropriate checks to the
assembly.

Since BMIPS43XX and BMIPS5000 require different IPI implementations,
split the SMP ops into one for each, so the runtime overhead is only
at registration time for them.
Signed-off-by: NJonas Gorski <jogo@openwrt.org>
Signed-off-by: NJohn Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/6241/

Panic() is going to add a \n itself and it's annoying if a panic message rolls
of the screen on a device with no scrollback.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The hardware interrupt routing for boot CPU != 0 is wrong because it
will route all the hardware interrupts to TP0 which is not the one we
booted from. Fix this by properly checking which boot CPU we are booting
from and updating the right interrupt mask for the boot CPU. This fixes
booting on BCM3368 with bmips_smp_emabled = 0.
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: blogic@openwrt.org
Cc: jogo@openwrt.org
Cc: cernekee@gmail.com
Patchwork: https://patchwork.linux-mips.org/patch/5650/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The current BMIPS SMP code assumes that the slave CPU is physical and
logical CPU 1, but on some systems such as BCM3368, the slave CPU is
physical CPU0. Fix the code to read the physical CPU (thread ID) we are
running this code on, and adjust the relocation vector address based on
it. This allows bringing up the second CPU on BCM3368 for instance.
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: cernekee@gmail.com
Cc: jogo@openwrt.org
Cc: blogic@openwrt.org
Patchwork: https://patchwork.linux-mips.org/patch/5621/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Commit 4df715aa ("MIPS: BMIPS: support booting from physical CPU other
than 0") changed the interupt routing when we are booting from physical
CPU 0, but the settings are actually correct if we are booting from
physical CPU 0 or CPU 1. Revert that specific change.
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: cernekee@gmail.com
Cc: jogo@openwrt.org
Cc: blogic@openwrt.org
Patchwork: https://patchwork.linux-mips.org/patch/5622/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Commit 4df715aa ["MIPS: BMIPS: support booting from physical CPU other
than 0"] introduced a thinko which will prevents slave CPUs from being
released from reset on systems where we boot from TP0. The problem is
that we are checking whether the slave CPU logical CPU map is 0, which
is never true for systems booting from TP0, so we do not release the
slave TP from reset and we are just stuck. Fix this by properly checking
that the CPU we intend to boot really is the physical slave CPU (logical
and physical value being 1).
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: blogic@openwrt.org
Cc: jogo@openwrt.org
Cc: cernekee@gmail.com
Cc: Florian Fainelli <florian@openwrt.org>
Patchwork: https://patchwork.linux-mips.org/patch/5598/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

commit 3747069b25e419f6b51395f48127e9812abc3596 upstream.

The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
and are flagged as __cpuinit  -- so if we remove the __cpuinit from
the arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
related content into no-ops as early as possible, since that will get
rid of these warnings.  In any case, they are temporary and harmless.

Here, we remove all the MIPS __cpuinit from C code and __CPUINIT
from asm files.  MIPS is interesting in this respect, because there
are also uasm users hiding behind their own renamed versions of the
__cpuinit macros.

[1] https://lkml.org/lkml/2013/5/20/589

[ralf@linux-mips.org: Folded in Paul's followup fix.]
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5494/
Patchwork: https://patchwork.linux-mips.org/patch/5495/
Patchwork: https://patchwork.linux-mips.org/patch/5509/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

BMIPS43xx CPUs have two hardware threads, and on some SoCs such as 3368,
the bootloader has configured the system to boot from TP1 instead of the
more usual TP0. Create the physical to logical CPU mapping to cope with
that, do not remap the software interrupts to be cross CPUs such that we
do not have to do use the logical CPU mapping further down the code, and
finally, reset the slave TP1 only if booted from TP0.
Signed-off-by: NJonas Gorski <jogo@openwrt.org>
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: blogic@openwrt.org
Cc: cernekee@gmail.com
Patchwork: https://patchwork.linux-mips.org/patch/5553/
Patchwork: https://patchwork.linux-mips.org/patch/5556/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

To prepare for smoothing set_cpu_[active|online]() mess up
Signed-off-by: NYong Zhang <yong.zhang0@gmail.com>
Cc: Sergei Shtylyov <sshtylyov@mvista.com>
Cc: David Daney <david.daney@cavium.com>
Acked-by: NDavid Daney <david.daney@cavium.com>
Patchwork: https://patchwork.linux-mips.org/patch/3846/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NDanny Kukawka <danny.kukawka@bisect.de>
Cc: Danny Kukawka <dkukawka@suse.de>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/3369/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This has been obsolescent for a while; time for the final push.

In adjacent context, replaced old cpus_* with cpumask_*.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Acked-by: David S. Miller <davem@davemloft.net> (arch/sparc)
Acked-by: Chris Metcalf <cmetcalf@tilera.com> (arch/tile)
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: linux-hexagon@vger.kernel.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Helge Deller <deller@gmx.de>
Cc: sparclinux@vger.kernel.org

Disintegrate asm/system.h for MIPS.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
cc: linux-mips@linux-mips.org

As 'make versioncheck' nicely points out, arch/mips/kernel/smp-bmips.c
has no need to '#include <linux/version.h>'. This patch removes the
unneeded include.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: trivial@kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/3269/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Initial commit of BMIPS SMP support code.  Smoke-tested on a variety of
BMIPS4350, BMIPS4380, and BMIPS5000 platforms.
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2977/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>