While the 5KE processors have never been taped out, they exists though
a CP0.PRId and experimental RTLs or QEMU implementations. Add a case
entry in the idle code, as they can use the standard idle loop like the
5K processors.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11099/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Prior to release 6 of the MIPS architecture it has been implementation
dependent whether masked interrupts cause a wait instruction to return,
so the kernel has effectively had to maintain a whitelist of cores upon
which it is safe to use the r4k_wait_irqoff cpu_wait implementation.
With MIPSr6 this is no longer implementation dependent and
r4k_wait_irqoff can always be used.
Remove the existing I6400 case which will no longer ever be hit, and was
incorrect anyway since I6400 & r6 in general doesn't have the WII bit.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/11210/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
BCM7425 CPU Interface Zephyr Processor, pages 5-309 and 5-310
BCM7428B0 CPU Interface Zephyr Processor, pages 5-337 and 5-338
WAIT instruction:
Thread enters wait state. No instructions are executed until an
interrupt occurs. The processor's clocks are stopped if both threads
are in idle mode.
Description:
Execution of this instruction puts the thread into wait state, an idle
mode in which no instructions are fetched or executed. The thread remains
in wait state until an interrupt occurs that is not masked by the
interrupt mask field in the Status register. Then, if interrupts are
enabled by the IE bit in the Status register, the interrupt is serviced.
The ERET instruction returns to the instruction following the WAIT
instruction. If interrupts are disabled, the processor resumes executing
instructions with the next sequential instruction.
Programming notes:
The WAIT instruction should be executed while interrupts are disabled
by the IE bit in the Status register. This avoids a potential timing
hazard, which occurs if an interrupt is taken between testing the counter
and executing the WAIT instruction. In this hazard case, the interrupt
will have been completed before the WAIT instruction is executed, so
the processor will remain indefinitely in wait state until the next
interrupt.
Signed-off-by: Petri Gynther <pgynther@google.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: cernekee@gmail.com
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11322/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add a CPU_I6400 case to various switch statements, doing the same thing
as for CPU_P5600.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10635/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
On certain cores (namely proAptiv and P5600) incoming data via a Fast
Debug Channel (FDC) while the core is blocked on a wait instruction will
cause the wait not to wake up even when another interrupt is received.
This makes an idle target stop as soon as you send FDC data to it, until
the debug probe interrupts it and restarts the wait instruction.
This is worked around by avoiding using r4k_wait on these cores if
CONFIG_MIPS_EJTAG_FDC_TTY is enabled (which would imply the user intends
to use the FDC).
[ralf@linux-mips.org: Fix conflict.]
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/9144/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add a CPU_QEMU_GENERIC case to various switch statements.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
The __pastwait symbol was only used by the address_is_in_r4k_wait_irqoff
function but this is no longer used since the SMTC removal in commit
b633648c5a ('MIPS: MT: Remove SMTC support'). That symbol also led to
build failures under certain random configuration due to the way the
compiler compiled the r4k_wait_irqoff function. If that function was
called multiple times, the __pastwait symbol was redefined breaking the
build like this:
CHK include/generated/compile.h
CC arch/mips/kernel/idle.o
{standard input}: Assembler messages:
{standard input}:527: Error: symbol `__pastwait' is already defined
Link: http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=1244879922.24479.30.camel%40falcon
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/7791/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Defines a macro intended to allow trivial use of the regular MIPS wait
instruction from cpuidle drivers, which may simply invoke the macro
within their array of states.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Nobody is maintaining SMTC anymore and there also seems to be no userbase.
Which is a pity - the SMTC technology primarily developed by Kevin D.
Kissell <kevink@paralogos.com> is an ingenious demonstration for the MT
ASE's power and elegance.
Based on Markos Chandras <Markos.Chandras@imgtec.com> patch
https://patchwork.linux-mips.org/patch/6719/ which while very similar did
no longer apply cleanly when I tried to merge it plus some additional
post-SMTC cleanup - SMTC was a feature as tricky to remove as it was to
merge once upon a time.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
With binutils 2.24 the attempt to switch with microMIPS mode to MIPS III
mode through .set mips3 results in *lots* of warnings like
{standard input}: Assembler messages:
{standard input}:397: Warning: the 64-bit MIPS architecture does not support the `smartmips' extension
during a kernel build. Fixed by using .set arch=r4000 instead.
This breaks support for building the kernel with binutils 2.13 which
was supported for 32 bit kernels only anyway and 2.14 which was a bad
vintage for MIPS anyway.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The M5150 core is a 32-bit MIPS RISC which implements the
MIPS Architecture Release-5 in a 5-stage pipeline.
In addition, it includes the MIPS Architecture Virtualization Module
that enables virtualization of operating systems,
which provides a scalable, trusted, and secure execution environment.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6596/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add a CPU_P5600 case to various switch statements, doing the same thing
as for CPU_PROAPTIV.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6408/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The 1074K is a multiprocessing coherent processing system (CPS) based
on modified 74K cores. This patch makes the 1074K an actual unique
CPU type, instead of a 74K derivative, which it is not.
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Reviewed-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6389/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The interAptiv is a power-efficient multi-core microprocessor
for use in system-on-chip (SoC) applications. The interAptiv combines
a multi-threading pipeline with a coherence manager to deliver improved
computational throughput and power efficiency. The interAptiv can
contain one to four MIPS32R3 interAptiv cores, system level
coherence manager with L2 cache, optional coherent I/O port,
and optional floating point unit.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/6163/
The proAptiv Multiprocessing System is a power efficient multi-core
microprocessor for use in system-on-chip (SoC) applications.
The proAptiv Multiprocessing System combines a deep pipeline
with multi-issue out of order execution for improved computational
throughput. The proAptiv Multiprocessing System can contain one to
six MIPS32r3 proAptiv cores, system level coherence
manager with L2 cache, optional coherent I/O port, and optional
floating point unit.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/6134/
o Move current_cpu_type() to a separate header file
o #ifdefing on supported CPU types lets modern GCC know that certain
code in callers may be discarded ideally turning current_cpu_type() into
a function returning a constant.
o Use current_cpu_type() rather than direct access to struct cpuinfo_mips.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5833/
Only an interrupt can wake the core from 'wait', enable interrupts
locally before executing 'wait'.
[ralf@linux-mips.org: This leave the race between an interrupt that's
setting TIF_NEED_RESCHEd and entering the WAIT status. but at least it's
going to bring Alchemy back from the dead, so I'm going to apply this
patch.]
Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/5408/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
local_irq_enable() may expand into very different code, so it rather should
stay in C. Also this keeps the assembler code size constant which keeps
the rollback code simple. So it's best to split r4k_wait into two parts,
one C and one assembler.
Finally add the local_irq_enable() to r4k_wait to ensure the WAIT
instruction in __r4k_wait() will work properly.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
