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Pull Hyper-V updates from Wei Liu:
- a series from Boqun Feng to support page size larger than 4K
- a few miscellaneous clean-ups
* tag 'hyperv-next-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
hv: clocksource: Add notrace attribute to read_hv_sched_clock_*() functions
x86/hyperv: Remove aliases with X64 in their name
PCI: hv: Document missing hv_pci_protocol_negotiation() parameter
scsi: storvsc: Support PAGE_SIZE larger than 4K
Driver: hv: util: Use VMBUS_RING_SIZE() for ringbuffer sizes
HID: hyperv: Use VMBUS_RING_SIZE() for ringbuffer sizes
Input: hyperv-keyboard: Use VMBUS_RING_SIZE() for ringbuffer sizes
hv_netvsc: Use HV_HYP_PAGE_SIZE for Hyper-V communication
hv: hyperv.h: Introduce some hvpfn helper functions
Drivers: hv: vmbus: Move virt_to_hvpfn() to hyperv header
Drivers: hv: Use HV_HYP_PAGE in hv_synic_enable_regs()
Drivers: hv: vmbus: Introduce types of GPADL
Drivers: hv: vmbus: Move __vmbus_open()
Drivers: hv: vmbus: Always use HV_HYP_PAGE_SIZE for gpadl
drivers: hv: remove cast from hyperv_die_event
Pull timekeeping updates from Thomas Gleixner:
"Updates for timekeeping, timers and related drivers:
Core:
- Early boot support for the NMI safe timekeeper by utilizing
local_clock() up to the point where timekeeping is initialized.
This allows printk() to store multiple timestamps in the ringbuffer
which is useful for coordinating dmesg information across a fleet
of machines.
- Provide a multi-timestamp accessor for printk()
- Make timer init more robust by checking for invalid timer flags.
- Comma vs semicolon fixes
Drivers:
- Support for new platforms in existing drivers (SP804 and Renesas
CMT)
- Comma vs semicolon fixes
* tag 'timers-core-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource/drivers/armada-370-xp: Use semicolons rather than commas to separate statements
clocksource/drivers/mps2-timer: Use semicolons rather than commas to separate statements
timers: Mask invalid flags in do_init_timer()
clocksource/drivers/sp804: Enable Hisilicon sp804 timer 64bit mode
clocksource/drivers/sp804: Add support for Hisilicon sp804 timer
clocksource/drivers/sp804: Support non-standard register offset
clocksource/drivers/sp804: Prepare for support non-standard register offset
clocksource/drivers/sp804: Remove a mismatched comment
clocksource/drivers/sp804: Delete the leading "__" of some functions
clocksource/drivers/sp804: Remove unused sp804_timer_disable() and timer-sp804.h
clocksource/drivers/sp804: Cleanup clk_get_sys()
dt-bindings: timer: renesas,cmt: Document r8a774e1 CMT support
dt-bindings: timer: renesas,cmt: Document r8a7742 CMT support
alarmtimer: Convert comma to semicolon
timekeeping: Provide multi-timestamp accessor to NMI safe timekeeper
timekeeping: Utilize local_clock() for NMI safe timekeeper during early boot
clint_time_val will soon be used by the RISC-V implementation of
random_get_entropy(), which is a static inline function that may be used by
modules (at least CRYPTO_JITTERENTROPY=m).
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Pull timer updates from Thomas Gleixner:
"A set of clocksource/clockevents updates:
- Reset the TI/DM timer before enabling it instead of doing it the
other way round.
- Initialize the reload value for the GX6605s timer correctly so the
hardware counter starts at 0 again after overrun.
- Make error return value negative in the h8300 timer init function"
* tag 'timers-urgent-2020-09-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource/drivers/timer-gx6605s: Fixup counter reload
clocksource/drivers/timer-ti-dm: Do reset before enable
clocksource/drivers/h8300_timer8: Fix wrong return value in h8300_8timer_init()
The ARM SP804 supports a maximum of 32-bit counter, but Hisilicon extends
it to 64-bit. That means, the registers: TimerXload, TimerXValue and
TimerXBGLoad are 64bits, all other registers are the same as those in the
SP804. The driver code can be completely reused except that the register
offset is different.
Use compatible = "hisilicon,sp804" mark as Hisilicon sp804 timer.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200918132237.3552-8-thunder.leizhen@huawei.com
The ARM SP804 supports a maximum of 32-bit counter, but Hisilicon extends
it to 64-bit. That means, the registers: TimerXload, TimerXValue and
TimerXBGLoad are 64bits, all other registers are the same as those in the
SP804. The driver code can be completely reused except that the register
offset is different.
Currently, we get a timer register address by: add the constant register
offset to the timer base address. e.g. "base + TIMER_CTRL". It can not be
dynamically adjusted at run time.
So create a new structure "sp804_timer" to record the original registers
offset, and create a new structure "sp804_clkevt" to record the
calculated registers address. So the "base + TIMER_CTRL" is changed to
"clkevt->ctrl", this will faster than "base + timer->ctrl".
For example:
struct sp804_timer arm_sp804_timer = {
.ctrl = TIMER_CTRL,
};
struct sp804_clkevt clkevt;
clkevt.ctrl = base + arm_sp804_timer.ctrl.
- writel(0, base + TIMER_CTRL);
+ writel(0, clkevt->ctrl);
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200918132237.3552-7-thunder.leizhen@huawei.com
writel(0, base + TIMER_CTRL);
... ...
writel(xxx | TIMER_CTRL_PERIODIC, base + TIMER_CTRL);
The timer is just temporarily disabled, and it will be set to periodic
mode later.
The description of the field TimerMode of the register TimerXControl
as shown below:
0 = Timer module is in free-running mode (default)
1 = Timer module is in periodic mode.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200918132237.3552-5-thunder.leizhen@huawei.com
Pull RISC-V fixes from Palmer Dabbelt:
- A fix for a lockdep issue to avoid an asserting triggering during
early boot. There shouldn't be any incorrect behavior as the system
isn't concurrent at the time.
- The addition of a missing fence when installing early fixmap
mappings.
- A corretion to the K210 device tree's interrupt map.
- A fix for M-mode timer handling on the K210.
* tag 'riscv-for-linus-5.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
RISC-V: Resurrect the MMIO timer implementation for M-mode systems
riscv: Fix Kendryte K210 device tree
riscv: Add sfence.vma after early page table changes
RISC-V: Take text_mutex in ftrace_init_nop()
The K210 doesn't implement rdtime in M-mode, and since that's where Linux runs
in the NOMMU systems that means we can't use rdtime. The K210 is the only
system that anyone is currently running NOMMU or M-mode on, so here we're just
inlining the timer read directly.
This also adds the CLINT driver as an !MMU dependency, as it's currently the
only timer driver availiable for these systems and without it we get a build
failure for some configurations.
Tested-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Commit 6cfcd5563b ("clocksource/drivers/timer-ti-dm: Fix suspend and
resume for am3 and am4") exposed a new issue for type2 dual mode timers
on at least omap5 where the clockevent will stop when the SoC starts
entering idle states during the boot.
Turns out we are wrongly first enabling the system timer and then
resetting it, while we must also re-enable it after reset. The current
sequence leaves the timer module in a partially initialized state. This
issue went unnoticed earlier with ti-sysc driver reconfiguring the timer
module until we fixed the issue of ti-sysc reconfiguring system timers.
Let's fix the issue by calling dmtimer_systimer_enable() from reset for
both type1 and type2 timers, and switch the order of reset and enable in
dmtimer_systimer_setup(). Let's also move dmtimer_systimer_enable() and
dmtimer_systimer_disable() to do this without adding forward declarations.
Fixes: 6cfcd5563b ("clocksource/drivers/timer-ti-dm: Fix suspend and resume for am3 and am4")
Reported-by: H. Nikolaus Schaller" <hns@goldelico.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200817092428.6176-1-tony@atomide.com
Right now the RISC-V timer driver is convoluted to support:
1. Linux RISC-V S-mode (with MMU) where it will use TIME CSR for
clocksource and SBI timer calls for clockevent device.
2. Linux RISC-V M-mode (without MMU) where it will use CLINT MMIO
counter register for clocksource and CLINT MMIO compare register
for clockevent device.
We now have a separate CLINT timer driver which also provide CLINT
based IPI operations so let's remove CLINT MMIO related code from
arch/riscv directory and RISC-V timer driver.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Tested-by: Emil Renner Berhing <kernel@esmil.dk>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Pull MFD updates from Lee Jones:
"Core Frameworks
- Make better attempt at matching device with the correct OF node
- Allow batch removal of hierarchical sub-devices
New Drivers
- Add STM32 Clocksource driver
- Add support for Khadas System Control Microcontroller
Driver Removal
- Remove unused driver for TI's SMSC ECE1099
New Device Support
- Add support for Intel Emmitsburg PCH to Intel LPSS PCI
- Add support for Intel Tiger Lake PCH-H to Intel LPSS PCI
- Add support for Dialog DA revision to Dialog DA9063
New Functionality
- Add support for AXP803 to be probed by I2C
Fix-ups
- Numerous W=1 warning fixes
- Device Tree changes (stm32-lptimer, gateworks-gsc, khadas,mcu, stmfx, cros-ec, j721e-system-controller)
- Enabled Regmap 'fast I/O' in stm32-lptimer
- Change BUG_ON to WARN_ON in arizona-core
- Remove superfluous code/initialisation (madera, max14577)
- Trivial formatting/spelling issues (madera-core, madera-i2c, da9055, max77693-private)
- Switch to of_platform_populate() in sprd-sc27xx-spi
- Expand out set/get brightness/pwm macros in lm3533-ctrlbank
- Disable IRQs on suspend in motorola-cpcap
- Clean-up error handling in intel_soc_pmic_mrfld
- Ensure correct removal order of sub-devices in madera
- Many s/HTTP/HTTPS/ link changes
- Ensure name used with Regmap is unique in syscon
Bug Fixes
- Properly 'put' clock on unbind and error in arizona-core
- Fix revision handling in da9063
- Fix 'assignment of read-only location' error in kempld-core
- Avoid using the Regmap API when atomic in rn5t618
- Redefine volatile register description in rn5t618
- Use locking to protect event handler in dln2"
* tag 'mfd-next-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd: (76 commits)
mfd: syscon: Use a unique name with regmap_config
mfd: Replace HTTP links with HTTPS ones
mfd: dln2: Run event handler loop under spinlock
mfd: madera: Improve handling of regulator unbinding
mfd: mfd-core: Add mechanism for removal of a subset of children
mfd: intel_soc_pmic_mrfld: Simplify the return expression of intel_scu_ipc_dev_iowrite8()
mfd: max14577: Remove redundant initialization of variable current_bits
mfd: rn5t618: Fix caching of battery related registers
mfd: max77693-private: Drop a duplicated word
mfd: da9055: pdata.h: Drop a duplicated word
mfd: rn5t618: Make restart handler atomic safe
mfd: kempld-core: Fix 'assignment of read-only location' error
mfd: axp20x: Allow the AXP803 to be probed by I2C
mfd: da9063: Add support for latest DA silicon revision
mfd: da9063: Fix revision handling to correctly select reg tables
dt-bindings: mfd: st,stmfx: Remove I2C unit name
dt-bindings: mfd: ti,j721e-system-controller.yaml: Add J721e system controller
mfd: motorola-cpcap: Disable interrupt for suspend
mfd: smsc-ece1099: Remove driver
mfd: core: Add OF_MFD_CELL_REG() helper
...
Pull timer updates from Thomas Gleixner:
"Time, timers and related driver updates:
- Prevent unnecessary timer softirq invocations by extending the
tracking of the next expiring timer in the timer wheel beyond the
existing NOHZ functionality.
The tracking overhead at enqueue time is within the noise, but on
sensitive workloads the avoidance of the soft interrupt invocation
is a measurable improvement.
- The obligatory new clocksource driver for Ingenic X100 OST
- The usual fixes, improvements, cleanups and extensions for newer
chip variants all over the driver space"
* tag 'timers-core-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (28 commits)
timers: Recalculate next timer interrupt only when necessary
clocksource/drivers/ingenic: Add support for the Ingenic X1000 OST.
dt-bindings: timer: Add Ingenic X1000 OST bindings.
clocksource/drivers: Replace HTTP links with HTTPS ones
clocksource/drivers/nomadik-mtu: Handle 32kHz clock
clocksource/drivers/sh_cmt: Use "kHz" for kilohertz
clocksource/drivers/imx: Add support for i.MX TPM driver with ARM64
clocksource/drivers/ingenic: Add high resolution timer support for SMP/SMT.
timers: Lower base clock forwarding threshold
timers: Remove must_forward_clk
timers: Spare timer softirq until next expiry
timers: Expand clk forward logic beyond nohz
timers: Reuse next expiry cache after nohz exit
timers: Always keep track of next expiry
timers: Optimize _next_timer_interrupt() level iteration
timers: Add comments about calc_index() ceiling work
timers: Move trigger_dyntick_cpu() to enqueue_timer()
timers: Use only bucket expiry for base->next_expiry value
timers: Preserve higher bits of expiration on index calculation
clocksource/drivers/timer-atmel-tcb: Add sama5d2 support
...
Pull timer fix from Ingo Molnar:
"Fix a suspend/resume regression (crash) on TI AM3/AM4 SoC's"
* tag 'timers-urgent-2020-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource/drivers/timer-ti-dm: Fix suspend and resume for am3 and am4
Pull clock event/surce driver changes from Daniel Lezcano:
- Add sama5d2 support and rework the 32kHz clock handling (Alexandre Belloni)
- Add the high resolution support for SMP/SMT on the Ingenic timer (Zhou Yanjie)
- Add support for i.MX TPM driver with ARM64 (Anson Huang)
- Fix typo by replacing KHz to kHz (Geert Uytterhoeven)
- Add 32kHz support by setting the minimum ticks to 5 on Nomadik MTU (Linus Walleij)
- Replace HTTP links with HTTPS ones for security reasons (Alexander A. Klimov)
- Add support for the Ingenic X1000 OST (Zhou Yanjie)
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.
Deterministic algorithm:
For each file:
If not .svg:
For each line:
If doesn't contain `\bxmlns\b`:
For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`:
If both the HTTP and HTTPS versions
return 200 OK and serve the same content:
Replace HTTP with HTTPS.
Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200708165856.15322-1-grandmaster@al2klimov.de
Carlos Hernandez <ceh@ti.com> reported that we now have a suspend and
resume regresssion on am3 and am4 compared to the earlier kernels. While
suspend and resume works with v5.8-rc3, we now get errors with rtcwake:
pm33xx pm33xx: PM: Could not transition all powerdomains to target state
...
rtcwake: write error
This is because we now fail to idle the system timer clocks that the
idle code checks and the error gets propagated to the rtcwake.
Turns out there are several issues that need to be fixed:
1. Ignore no-idle and no-reset configured timers for the ti-sysc
interconnect target driver as otherwise it will keep the system timer
clocks enabled
2. Toggle the system timer functional clock for suspend for am3 and am4
(but not for clocksource on am3)
3. Only reconfigure type1 timers in dmtimer_systimer_disable()
4. Use of_machine_is_compatible() instead of of_device_is_compatible()
for checking the SoC type
Fixes: 52762fbd1c ("clocksource/drivers/timer-ti-dm: Add clockevent and clocksource support")
Reported-by: Carlos Hernandez <ceh@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Tested-by: Carlos Hernandez <ceh@ti.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200713162601.6829-1-tony@atomide.com
Implement clock event driver using low power STM32 timers.
Low power timer counters running even when CPUs are stopped.
It could be used as clock event broadcaster to wake up CPUs but not like
a clocksource because each it rise an interrupt the counter restart from 0.
Low power timers have a 16 bits counter and a prescaler which allow to
divide the clock per power of 2 to up 128 to target a 32KHz rate.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Pascal Paillet <p.paillet@st.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Instead of directly calling RISC-V timer interrupt handler from
RISC-V local interrupt conntroller driver, this patch implements
RISC-V timer interrupt as a per-CPU interrupt using per-CPU APIs
of Linux IRQ subsystem.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Currently clocksource framework doesn't support the clocks with variable
frequency. Since MIPS GIC timer ticks rate might be unstable on some
platforms, we must make sure that it justifies the clocksource
requirements. MIPS GIC timer is incremented with the CPU cluster reference
clocks rate. So in case if CPU frequency changes, the MIPS GIC tick rate
changes synchronously. Due to this the clocksource subsystem can't rely on
the timer to measure system clocks anymore. This commit marks the MIPS GIC
based clocksource as unstable if reference clock (normally it's a CPU
reference clocks) rate changes. The clocksource will execute a watchdog
thread, which lowers the MIPS GIC timer rating to zero and fallbacks to a
new stable one.
Note we don't need to set the CLOCK_SOURCE_MUST_VERIFY flag to the MIPS
GIC clocksource since normally the timer is stable. The only reason why
it gets unstable is due to the ref clock rate change, which event we
detect here in the driver by means of the clocks event notifier.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200521204818.25436-9-Sergey.Semin@baikalelectronics.ru
The MIPS GIC timer is well suited for use as sched_clock, so register it
as such.
Whilst the existing gic_read_count() function matches the prototype
needed by sched_clock_register() already, we split it into 2 functions
in order to remove the need to evaluate the mips_cm_is64 condition
within each call since sched_clock should be as fast as possible.
Note the sched clock framework needs the clock source being stable in
order to rely on it. So we register the MIPS GIC timer as schedule clocks
only if it's, if either the system doesn't have CPU-frequency enabled or
the CPU frequency is changed by means of the CPC core clock divider
available on the platforms with CM3 or newer.
Signed-off-by: Paul Burton <paulburton@kernel.org>
Co-developed-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
[Sergey.Semin@baikalelectronics.ru: Register sched-clock if CM3 or !CPU-freq]
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200521204818.25436-8-Sergey.Semin@baikalelectronics.ru
Commit 1002148899 ("clocksource: dw_apb_timer_of: use
clocksource_of_init") replaced a publicly available driver
initialization method with one called by the timer_probe() method
available after CLKSRC_OF. In current implementation it traverses
all the timers available in the system and calls their initialization
methods if corresponding devices were either in dtb or in acpi. But
if before the commit any number of available timers would be installed
as clockevent and clocksource devices, after that there would be at most
two. The rest are just ignored since default case branch doesn't do
anything. I don't see a reason of such behaviour, neither the commit
message explains it. Moreover this might be wrong if on some platforms
these timers might be used for different purpose, as virtually CPU-local
clockevent timers and as an independent broadcast timer. So in order
to keep the compatibility with the platforms where the order of the
timers detection has some meaning, lets add the secondly discovered
timer to be of clocksource/sched_clock type, while the very first and
the others would provide the clockevents service.
Fixes: 1002148899 ("clocksource: dw_apb_timer_of: use clocksource_of_init")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200521204818.25436-7-Sergey.Semin@baikalelectronics.ru
Currently the DW APB Timer driver binds each clockevent timers to a
particular CPU. This isn't good for multiple reasons. First of all seeing
the device is placed on APB bus (which makes it accessible from any CPU
core), accessible over MMIO and having the DYNIRQ flag set we can be sure
that manually binding the timer to any CPU just isn't correct. By doing
so we just set an extra limitation on device usage. This also doesn't
reflect the device actual capability, since by setting the IRQ affinity
we can make it virtually local to any CPU. Secondly imagine if you had a
real CPU-local timer with the same rating and the same CPU-affinity.
In this case if DW APB timer was registered first, then due to the
clockevent framework tick-timer selection procedure we'll end up with the
real CPU-local timer being left unselected for clock-events tracking. But
on most of the platforms (MIPS/ARM/etc) such timers are normally embedded
into the CPU core and are accessible with much better performance then
devices placed on APB. For instance in MIPS architectures there is
r4k-timer, which is CPU-local, assigned with the same rating, and normally
its clockevent device is registered after the platform-specific one.
So in order to fix all of these issues let's make the DW APB Timer CPU
affinity being optional and deactivated by passing a negative CPU id,
which will effectively set the DW APB clockevent timer cpumask to
'cpu_possible_mask'.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200521204818.25436-5-Sergey.Semin@baikalelectronics.ru