linux-toradex.git/arch/mips/dec, branch v3.12.18 Linux kernel for Apalis and Colibri modules MIPS: Optimize current_cpu_type() for better code. 2013-09-17T16:50:53+00:00 Ralf Baechle ralf@linux-mips.org 2013-09-17T08:25:47+00:00 69f24d1784b631b81a54eb57c49bf46536dd2382 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/ 
 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/
MIPS: DECstation I/O ASIC DMA interrupt handling fix 2013-09-13T09:57:40+00:00 Maciej W. Rozycki macro@linux-mips.org 2013-09-12T11:14:31+00:00 5359b938c088423a28c41499f183cd10824c1816 This change complements commit d0da7c002f7b2a93582187a9e3f73891a01d8ee4 and brings clear_ioasic_irq back, renaming it to clear_ioasic_dma_irq at the same time, to make I/O ASIC DMA interrupts functional. Unlike ordinary I/O ASIC interrupts DMA interrupts need to be deasserted by software by writing 0 to the respective bit in I/O ASIC's System Interrupt Register (SIR), similarly to how CP0.Cause.IP0 and CP0.Cause.IP1 bits are handled in the CPU (the difference is SIR DMA interrupt bits are R/W0C so there's no need for an RMW cycle). Otherwise the handler is reentered over and over again. The only current user is the DEC LANCE Ethernet driver and its extremely uncommon DMA memory error handler that does not care when exactly the interrupt is cleared. Anticipating the use of DMA interrupts by the Zilog SCC driver this change however exports clear_ioasic_dma_irq for device drivers to choose the right application-specific sequence to clear the request explicitly rather than calling it implicitly in the .irq_eoi handler of `struct irq_chip'. Previously these interrupts were cleared in the .end handler of the said structure, before it was removed. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/5826/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
This change complements commit d0da7c002f7b2a93582187a9e3f73891a01d8ee4
and brings clear_ioasic_irq back, renaming it to clear_ioasic_dma_irq at
the same time, to make I/O ASIC DMA interrupts functional.

Unlike ordinary I/O ASIC interrupts DMA interrupts need to be deasserted
by software by writing 0 to the respective bit in I/O ASIC's System
Interrupt Register (SIR), similarly to how CP0.Cause.IP0 and CP0.Cause.IP1
bits are handled in the CPU (the difference is SIR DMA interrupt bits are
R/W0C so there's no need for an RMW cycle).  Otherwise the handler is
reentered over and over again.

The only current user is the DEC LANCE Ethernet driver and its extremely
uncommon DMA memory error handler that does not care when exactly the
interrupt is cleared.  Anticipating the use of DMA interrupts by the Zilog
SCC driver this change however exports clear_ioasic_dma_irq for device
drivers to choose the right application-specific sequence to clear the
request explicitly rather than calling it implicitly in the .irq_eoi
handler of `struct irq_chip'.  Previously these interrupts were cleared in
the .end handler of the said structure, before it was removed.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5826/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: DECstation HRT initialization rearrangement 2013-09-13T09:56:13+00:00 Maciej W. Rozycki macro@linux-mips.org 2013-09-12T11:01:53+00:00 daed1285c33582d93447a0ad971bbc1dd15d1940 Not all I/O ASIC versions have the free-running counter implemented, an early revision used in the 5000/1xx models aka 3MIN and 4MIN did not have it. Therefore we cannot unconditionally use it as a clock source. Fortunately if not implemented its register slot has a fixed value so it is enough if we check for the value at the end of the calibration period being the same as at the beginning. This also means we need to look for another high-precision clock source on the systems affected. The 5000/1xx can have an R4000SC processor installed where the CP0 Count register can be used as a clock source. Unfortunately all the R4k DECstations suffer from the missed timer interrupt on CP0 Count reads erratum, so we cannot use the CP0 timer as a clock source and a clock event both at a time. However we never need an R4k clock event device because all DECstations have a DS1287A RTC chip whose periodic interrupt can be used as a clock source. This gives us the following four configuration possibilities for I/O ASIC DECstations: 1. No I/O ASIC counter and no CP0 timer, e.g. R3k 5000/1xx (3MIN). 2. No I/O ASIC counter but the CP0 timer, i.e. R4k 5000/150 (4MIN). 3. The I/O ASIC counter but no CP0 timer, e.g. R3k 5000/240 (3MAX+). 4. The I/O ASIC counter and the CP0 timer, e.g. R4k 5000/260 (4MAX+). For #1 and #2 this change stops the I/O ASIC free-running counter from being installed as a clock source of a 0Hz frequency. For #2 it also arranges for the CP0 timer to be used as a clock source rather than a clock event device, because having an accurate wall clock is more important than a high-precision interval timer. For #3 there is no change. For #4 the change makes the I/O ASIC free-running counter installed as a clock source so that the CP0 timer can be used as a clock event device. Unfortunately the use of the CP0 timer as a clock event device relies on a succesful completion of c0_compare_interrupt. That never happens, because while waiting for a CP0 Compare interrupt to happen the function spins in a loop reading the CP0 Count register. This makes the CP0 Count erratum trigger reliably causing the interrupt waited for to be lost in all cases. As a result #4 resorts to using the CP0 timer as a clock source as well, just as #2. However we want to keep this separate arrangement in case (hope) c0_compare_interrupt is eventually rewritten such that it avoids the erratum. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/5825/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
Not all I/O ASIC versions have the free-running counter implemented, an
early revision used in the 5000/1xx models aka 3MIN and 4MIN did not have
it.  Therefore we cannot unconditionally use it as a clock source.
Fortunately if not implemented its register slot has a fixed value so it
is enough if we check for the value at the end of the calibration period
being the same as at the beginning.

This also means we need to look for another high-precision clock source on
the systems affected.  The 5000/1xx can have an R4000SC processor
installed where the CP0 Count register can be used as a clock source.
Unfortunately all the R4k DECstations suffer from the missed timer
interrupt on CP0 Count reads erratum, so we cannot use the CP0 timer as a
clock source and a clock event both at a time.  However we never need an
R4k clock event device because all DECstations have a DS1287A RTC chip
whose periodic interrupt can be used as a clock source.

This gives us the following four configuration possibilities for I/O ASIC
DECstations:

1. No I/O ASIC counter and no CP0 timer, e.g. R3k 5000/1xx (3MIN).

2. No I/O ASIC counter but the CP0 timer, i.e. R4k 5000/150 (4MIN).

3. The I/O ASIC counter but no CP0 timer, e.g. R3k 5000/240 (3MAX+).

4. The I/O ASIC counter and the CP0 timer, e.g. R4k 5000/260 (4MAX+).

For #1 and #2 this change stops the I/O ASIC free-running counter from
being installed as a clock source of a 0Hz frequency.  For #2 it also
arranges for the CP0 timer to be used as a clock source rather than a
clock event device, because having an accurate wall clock is more
important than a high-precision interval timer.  For #3 there is no
change.  For #4 the change makes the I/O ASIC free-running counter
installed as a clock source so that the CP0 timer can be used as a clock
event device.

Unfortunately the use of the CP0 timer as a clock event device relies on a
succesful completion of c0_compare_interrupt.  That never happens, because
while waiting for a CP0 Compare interrupt to happen the function spins in
a loop reading the CP0 Count register.  This makes the CP0 Count erratum
trigger reliably causing the interrupt waited for to be lost in all cases.
As a result #4 resorts to using the CP0 timer as a clock source as well,
just as #2.  However we want to keep this separate arrangement in case
(hope) c0_compare_interrupt is eventually rewritten such that it avoids
the erratum.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5825/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: DECstation HRT calibration bug fixes 2013-09-05T18:38:28+00:00 Maciej W. Rozycki macro@linux-mips.org 2013-09-04T22:47:45+00:00 8533966a6dba09d65a6764accdf44f3e96cddbfb This change corrects DECstation HRT calibration, by removing the following bugs: 1. Calibration period selection -- HZ / 10 has been chosen, however on DECstation computers, HZ never divides by 10, as the choice for HZ is among 128, 256 and 1024. The choice therefore results in a systematic calibration error, e.g. 6.25% for the usual choice of 128 for HZ: 128 / 10 * 10 = 120 (128 - 120) / 128 -> 6.25% The change therefore makes calibration use HZ / 8 that is always accurate for the HZ values available, getting rid of the systematic error. 2. Calibration starting point synchronisation -- the duration of a number of intervals between DS1287A periodic interrupt assertions is measured, however code does not ensure at the beginning that the interrupt has not been previously asserted. This results in a variable error of e.g. up to another 6.25% for the period of HZ / 8 (8.(3)% with the original HZ / 10 period) and the usual choice of 128 for HZ: 1 / 16 -> 6.25% 1 / 12 -> 8.(3)% The change therefore adds an initial call to ds1287_timer_state that clears any previous periodic interrupt pending. The same issue applies to both I/O ASIC counter and R4k CP0 timer calibration on DECstation systems as similar code is used in both cases and both pieces of code are covered by this fix. On an R3400 test system used this fix results in a change of the I/O ASIC clock frequency reported from values like: I/O ASIC clock frequency 23185830Hz to: I/O ASIC clock frequency 24999288Hz removing the miscalculation by 6.25% from the systematic error and (for the individual sample provided) a further 1.00% from the variable error, accordingly. The nominal I/O ASIC clock frequency is 25MHz on this system. Here's another result, with the fix applied, from a system that has both HRTs available (using an R4400 at 60MHz nominal): MIPS counter frequency 59999328Hz I/O ASIC clock frequency 24999432Hz Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/5807/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
This change corrects DECstation HRT calibration, by removing the following
bugs:

1. Calibration period selection -- HZ / 10 has been chosen, however on
   DECstation computers, HZ never divides by 10, as the choice for HZ is
   among 128, 256 and 1024.  The choice therefore results in a systematic
   calibration error, e.g. 6.25% for the usual choice of 128 for HZ:

   128 / 10 * 10 = 120

   (128 - 120) / 128 -> 6.25%

   The change therefore makes calibration use HZ / 8 that is always
   accurate for the HZ values available, getting rid of the systematic
   error.

2. Calibration starting point synchronisation -- the duration of a number
   of intervals between DS1287A periodic interrupt assertions is measured,
   however code does not ensure at the beginning that the interrupt has
   not been previously asserted.  This results in a variable error of e.g.
   up to another 6.25% for the period of HZ / 8 (8.(3)% with the original
   HZ / 10 period) and the usual choice of 128 for HZ:

   1 / 16 -> 6.25%

   1 / 12 -> 8.(3)%

   The change therefore adds an initial call to ds1287_timer_state that
   clears any previous periodic interrupt pending.

The same issue applies to both I/O ASIC counter and R4k CP0 timer
calibration on DECstation systems as similar code is used in both cases
and both pieces of code are covered by this fix.

On an R3400 test system used this fix results in a change of the I/O ASIC
clock frequency reported from values like:

I/O ASIC clock frequency 23185830Hz

to:

I/O ASIC clock frequency 24999288Hz

removing the miscalculation by 6.25% from the systematic error and (for
the individual sample provided) a further 1.00% from the variable error,
accordingly.  The nominal I/O ASIC clock frequency is 25MHz on this
system.

Here's another result, with the fix applied, from a system that has both
HRTs available (using an R4400 at 60MHz nominal):

MIPS counter frequency 59999328Hz
I/O ASIC clock frequency 24999432Hz

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5807/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: DEC: remove unbuildable promcon.c 2013-06-17T22:31:29+00:00 Paul Bolle pebolle@tiscali.nl 2013-05-30T09:20:15+00:00 9601cd159565fa228edc8e5ea3ed2c0ac3fb4d1f promcon.o is built if CONFIG_PROM_CONSOLE is set. But there's no Kconfig symbol PROM_CONSOLE, so promcon.c is unbuildable. Remove it. Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Acked-by: Maciej W. Rozycki <macro@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/5344/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
promcon.o is built if CONFIG_PROM_CONSOLE is set. But there's no Kconfig
symbol PROM_CONSOLE, so promcon.c is unbuildable. Remove it.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Acked-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/5344/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: Whitespace cleanup. 2013-02-01T09:00:22+00:00 Ralf Baechle ralf@linux-mips.org 2013-01-22T11:59:30+00:00 7034228792cc561e79ff8600f02884bd4c80e287 Having received another series of whitespace patches I decided to do this once and for all rather than dealing with this kind of patches trickling in forever. Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: DEC: use IS_ENABLED() 2012-07-23T12:55:54+00:00 Florian Fainelli florian@openwrt.org 2012-01-31T17:19:07+00:00 baf69e275317602bb1f2c87e40d1e03c90b31e38 Signed-off-by: Florian Fainelli <florian@openwrt.org> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/3333/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3333/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Disintegrate asm/system.h for MIPS 2012-03-28T17:30:02+00:00 David Howells dhowells@redhat.com 2012-03-28T17:30:02+00:00 b81947c646bfefdf98e2fde5d7d39cbbda8525d4 Disintegrate asm/system.h for MIPS. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> cc: linux-mips@linux-mips.org 
Disintegrate asm/system.h for MIPS.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
cc: linux-mips@linux-mips.org
MIPS: irq: Remove IRQF_DISABLED 2011-12-07T22:03:45+00:00 Yong Zhang yong.zhang0@gmail.com 2011-11-22T14:38:03+00:00 8b5690f8847490c1e3ea47266819833a13621253 Since commit [e58aa3d2: genirq: Run irq handlers with interrupts disabled], We run all interrupt handlers with interrupts disabled and we even check and yell when an interrupt handler returns with interrupts enabled (see commit [b738a50a: genirq: Warn when handler enables interrupts]). So now this flag is a NOOP and can be removed. [ralf@linux-mips.org: Fixed up conflicts in arch/mips/alchemy/common/dbdma.c, arch/mips/cavium-octeon/smp.c and arch/mips/kernel/perf_event.c.] Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> To: linux-kernel@vger.kernel.org Cc: tglx@linutronix.de linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2835/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
Since commit [e58aa3d2: genirq: Run irq handlers with interrupts disabled],
We run all interrupt handlers with interrupts disabled and we even check
and yell when an interrupt handler returns with interrupts enabled (see
commit [b738a50a: genirq: Warn when handler enables interrupts]).

So now this flag is a NOOP and can be removed.

[ralf@linux-mips.org: Fixed up conflicts in
arch/mips/alchemy/common/dbdma.c, arch/mips/cavium-octeon/smp.c and
arch/mips/kernel/perf_event.c.]

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: tglx@linutronix.de
linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2835/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
MIPS: Mark cascade and low level interrupts IRQF_NO_THREAD 2011-09-21T15:52:15+00:00 Wu Zhangjin wuzhangjin@gmail.com 2011-07-23T12:41:24+00:00 5a4a4ad851dd8db2d888fb86c8bd946b2ae79f60 Mark interrupts with no_action handler, cascade interrupts, low level interrupts (bus error, halt ..) with IRQF_NO_THREAD to exclude them from forced threading. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mips@linux-mips.org Cc: Wu Zhangjin <wuzhangjin@gmail.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org> 
Mark interrupts with no_action handler, cascade interrupts, low level
interrupts (bus error, halt ..) with IRQF_NO_THREAD to exclude them
from forced threading.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>