kernel/linux.git/drivers/clocksource, branch linux-6.0.y

clocksource/drivers/timer-ti-dm: Fix missing clk_disable_unprepare in dmtimer_systimer_init_clock()

2022-12-31T12:25:46+00:00

[ Upstream commit 180d35a7c05d520314a590c99ad8643d0213f28b ] If clk_get_rate() fails which is called after clk_prepare_enable(), clk_disable_unprepare() need be called in error path to disable the clock in dmtimer_systimer_init_clock(). Fixes: 52762fbd1c47 ("clocksource/drivers/timer-ti-dm: Add clockevent and clocksource support") Signed-off-by: Yang Yingliang Reviewed-by: Tony Lindgren Link: https://lore.kernel.org/r/20221029114427.946520-1-yangyingliang@huawei.com Signed-off-by: Daniel Lezcano Signed-off-by: Sasha Levin

clocksource/drivers/timer-ti-dm: Fix warning for omap_timer_match

2022-12-31T12:25:46+00:00

[ Upstream commit 9688498b1648aa98a3ee45d9f07763c099f6fb12 ] We can now get a warning for 'omap_timer_match' defined but not used. Let's fix this by dropping of_match_ptr for omap_timer_match. Reported-by: kernel test robot Fixes: ab0bbef3ae0f ("clocksource/drivers/timer-ti-dm: Make timer selectable for ARCH_K3") Signed-off-by: Tony Lindgren Link: https://lore.kernel.org/r/20221028103526.40319-1-tony@atomide.com Signed-off-by: Daniel Lezcano Signed-off-by: Sasha Levin

clocksource/drivers/sh_cmt: Access registers according to spec

2022-12-31T12:25:45+00:00

[ Upstream commit 3f44f7156f59cae06e9160eafb5d8b2dfd09e639 ] Documentation for most CMTs say that it takes two input clocks before changes propagate to the timer. This is especially relevant when the timer is stopped to change further settings. Implement the delays according to the spec. To avoid unnecessary delays in atomic mode, also check if the to-be-written value actually differs. CMCNT is a bit special because testing showed that it requires 3 cycles to propagate, which affects all CMTs. Also, the WRFLAG needs to be checked before writing. This fixes "cannot clear CMCNT" messages which occur often on R-Car Gen4 SoCs, but only very rarely on older SoCs for some reason. Fixes: 81b3b2711072 ("clocksource: sh_cmt: Add support for multiple channels per device") Signed-off-by: Wolfram Sang Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20221130210609.7718-1-wsa+renesas@sang-engineering.com Signed-off-by: Sasha Levin

Revert "clocksource/drivers/riscv: Events are stopped during CPU suspend"

2022-12-08T10:30:22+00:00

[ Upstream commit d9f15a9de44affe733e34f93bc184945ba277e6d ] This reverts commit 232ccac1bd9b5bfe73895f527c08623e7fa0752d. On the subject of suspend, the RISC-V SBI spec states: This does not cover whether any given events actually reach the hart or not, just what the hart will do if it receives an event. On PolarFire SoC, and potentially other SiFive based implementations, events from the RISC-V timer do reach a hart during suspend. This is not the case for the implementation on the Allwinner D1 - there timer events are not received during suspend. To fix this, the CLOCK_EVT_FEAT_C3STOP (mis)feature was enabled for the timer driver - but this has broken both RCU stall detection and timers generally on PolarFire SoC and potentially other SiFive based implementations. If an AXI read to the PCIe controller on PolarFire SoC times out, the system will stall, however, with CLOCK_EVT_FEAT_C3STOP active, the system just locks up without RCU stalling: io scheduler mq-deadline registered io scheduler kyber registered microchip-pcie 2000000000.pcie: host bridge /soc/pcie@2000000000 ranges: microchip-pcie 2000000000.pcie: MEM 0x2008000000..0x2087ffffff -> 0x0008000000 microchip-pcie 2000000000.pcie: sec error in pcie2axi buffer microchip-pcie 2000000000.pcie: ded error in pcie2axi buffer microchip-pcie 2000000000.pcie: axi read request error microchip-pcie 2000000000.pcie: axi read timeout microchip-pcie 2000000000.pcie: sec error in pcie2axi buffer microchip-pcie 2000000000.pcie: ded error in pcie2axi buffer microchip-pcie 2000000000.pcie: sec error in pcie2axi buffer microchip-pcie 2000000000.pcie: ded error in pcie2axi buffer microchip-pcie 2000000000.pcie: sec error in pcie2axi buffer microchip-pcie 2000000000.pcie: ded error in pcie2axi buffer Freeing initrd memory: 7332K Similarly issues were reported with clock_nanosleep() - with a test app that sleeps each cpu for 6, 5, 4, 3 ms respectively, HZ=250 & the blamed commit in place, the sleep times are rounded up to the next jiffy: == CPU: 1 == == CPU: 2 == == CPU: 3 == == CPU: 4 == Mean: 7.974992 Mean: 7.976534 Mean: 7.962591 Mean: 3.952179 Std Dev: 0.154374 Std Dev: 0.156082 Std Dev: 0.171018 Std Dev: 0.076193 Hi: 9.472000 Hi: 10.495000 Hi: 8.864000 Hi: 4.736000 Lo: 6.087000 Lo: 6.380000 Lo: 4.872000 Lo: 3.403000 Samples: 521 Samples: 521 Samples: 521 Samples: 521 Fortunately, the D1 has a second timer, which is "currently used in preference to the RISC-V/SBI timer driver" so a revert here does not hurt operation of D1 in its current form. Ultimately, a DeviceTree property (or node) will be added to encode the behaviour of the timers, but until then revert the addition of CLOCK_EVT_FEAT_C3STOP. Fixes: 232ccac1bd9b ("clocksource/drivers/riscv: Events are stopped during CPU suspend") Signed-off-by: Conor Dooley Signed-off-by: Thomas Gleixner Reviewed-by: Palmer Dabbelt Acked-by: Palmer Dabbelt Acked-by: Samuel Holland Link: https://lore.kernel.org/linux-riscv/YzYTNQRxLr7Q9JR0@spud/ Link: https://github.com/riscv-non-isa/riscv-sbi-doc/issues/98/ Link: https://lore.kernel.org/linux-riscv/bf6d3b1f-f703-4a25-833e-972a44a04114@sholland.org/ Link: https://lore.kernel.org/r/20221122121620.3522431-1-conor.dooley@microchip.com Signed-off-by: Sasha Levin

clocksource/drivers/arm_arch_timer: Fix XGene-1 TVAL register math error

2022-12-08T10:30:15+00:00

[ Upstream commit 839a973988a94c15002cbd81536e4af6ced2bd30 ] The TVAL register is 32 bit signed. Thus only the lower 31 bits are available to specify when an interrupt is to occur at some time in the near future. Attempting to specify a larger interval with TVAL results in a negative time delta which means the timer fires immediately upon being programmed, rather than firing at that expected future time. The solution is for Linux to declare that TVAL is a 31 bit register rather than give its true size of 32 bits. This prevents Linux from programming TVAL with a too-large value. Note that, prior to 5.16, this little trick was the standard way to handle TVAL in Linux, so there is nothing new happening here on that front. The softlockup detector hides the issue, because it keeps generating short timer deadlines that are within the scope of the broken timer. Disabling it, it starts using NO_HZ with much longer timer deadlines, which turns into an interrupt flood: 11: 1124855130 949168462 758009394 76417474 104782230 30210281 310890 1734323687 GICv2 29 Level arch_timer And "much longer" isn't that long: it takes less than 43s to underflow TVAL at 50MHz (the frequency of the counter on XGene-1). Some comments on the v1 version of this patch by Marc Zyngier: XGene implements CVAL (a 64bit comparator) in terms of TVAL (a countdown register) instead of the other way around. TVAL being a 32bit register, the width of the counter should equally be 32. However, TVAL is a *signed* value, and keeps counting down in the negative range once the timer fires. It means that any TVAL value with bit 31 set will fire immediately, as it cannot be distinguished from an already expired timer. Reducing the timer range back to a paltry 31 bits papers over the issue. Another problem cannot be fixed though, which is that the timer interrupt *must* be handled within the negative countdown period, or the interrupt will be lost (TVAL will rollover to a positive value, indicative of a new timer deadline). Fixes: 012f18850452 ("clocksource/drivers/arm_arch_timer: Work around broken CVAL implementations") Signed-off-by: Joe Korty Signed-off-by: Marc Zyngier Signed-off-by: Thomas Gleixner Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20221024165422.GA51107@zipoli.concurrent-rt.com Link: https://lore.kernel.org/r/20221121145343.896018-1-maz@kernel.org [maz: revamped the commit message] Signed-off-by: Sasha Levin

clocksource/drivers/timer-gxp: Add missing error handling in gxp_timer_probe

2022-10-21T10:39:00+00:00

[ Upstream commit 0e2c8e6d769bcdc4f6634a02c545356282275e68 ] Add platform_device_put() to make sure to free the platform device in the event platform_device_add() fails. Fixes: 5184f4bf151b ("clocksource/drivers/timer-gxp: Add HPE GXP Timer") Signed-off-by: Lin Yujun Link: https://lore.kernel.org/r/20220914033018.97484-1-linyujun809@huawei.com Signed-off-by: Daniel Lezcano Signed-off-by: Sasha Levin

clocksource/drivers/arm_arch_timer: Fix handling of ARM erratum 858921

2022-10-21T10:38:59+00:00

[ Upstream commit 6c3b62d93e195f78c1437c8fa7581e9b2f00886e ] The commit a38b71b0833e ("clocksource/drivers/arm_arch_timer: Move system register timer programming over to CVAL") moves the programming of the timers from the countdown timer (TVAL) over to the comparator (CVAL). This makes it necessary to read the counter when programming next event. However, the workaround of Cortex-A73 erratum 858921 does not set the corresponding set_next_event_phys and set_next_event_virt. Add the appropriate hooks to apply the erratum mitigation when programming the next timer event. Fixes: a38b71b0833e ("clocksource/drivers/arm_arch_timer: Move system register timer programming over to CVAL") Signed-off-by: Kunkun Jiang Acked-by: Marc Zyngier Reviewed-by: Oliver Upton Link: https://lore.kernel.org/r/20220914061424.1260-1-jiangkunkun@huawei.com Signed-off-by: Daniel Lezcano Signed-off-by: Sasha Levin

clocksource/drivers/arm_arch_timer: Fix CNTPCT_LO and CNTVCT_LO value

2022-10-21T10:37:42+00:00

commit af246cc6d0ed11318223606128bb0b09866c4c08 upstream. CNTPCT_LO and CNTVCT_LO are defined by mistake in commit '8b82c4f883a7', so fix them according to the Arm ARM DDI 0487I.a, Table I2-4 "CNTBaseN memory map" as follows: Offset Register Type Description 0x000 CNTPCT[31:0] RO Physical Count register. 0x004 CNTPCT[63:32] RO 0x008 CNTVCT[31:0] RO Virtual Count register. 0x00C CNTVCT[63:32] RO Fixes: 8b82c4f883a7 ("clocksource/drivers/arm_arch_timer: Move MMIO timer programming over to CVAL") Cc: stable@vger.kernel.org Cc: Daniel Lezcano Cc: Thomas Gleixner Cc: Marc Zyngier Cc: Mark Rutland Acked-by: Marc Zyngier Signed-off-by: Yang Guo Signed-off-by: Shaokun Zhang Link: https://lore.kernel.org/r/20220927033221.49589-1-zhangshaokun@hisilicon.com Signed-off-by: Daniel Lezcano Signed-off-by: Greg Kroah-Hartman

RISC-V: Add Sstc extension support

2022-08-11T21:41:52+00:00

This series implements Sstc extension support which was ratified recently. Before the Sstc extension, an SBI call is necessary to generate timer interrupts as only M-mode have access to the timecompare registers. Thus, there is significant latency to generate timer interrupts at kernel. For virtualized enviornments, its even worse as the KVM handles the SBI call and uses a software timer to emulate the timecomapre register. Sstc extension solves both these problems by defining a stimecmp/vstimecmp at supervisor (host/guest) level. It allows kernel to program a timer and recieve interrupt without supervisor execution enviornment (M-mode/HS mode) intervention. * palmer/riscv-sstc: RISC-V: Prefer sstc extension if available RISC-V: Enable sstc extension parsing from DT RISC-V: Add SSTC extension CSR details

RISC-V: Prefer sstc extension if available

2022-08-11T21:36:55+00:00

RISC-V ISA has sstc extension which allows updating the next clock event via a CSR (stimecmp) instead of an SBI call. This should happen dynamically if sstc extension is available. Otherwise, it will fallback to SBI call to maintain backward compatibility. Reviewed-by: Anup Patel Signed-off-by: Atish Patra Reviewed-by: Guo Ren Link: https://lore.kernel.org/r/20220722165047.519994-4-atishp@rivosinc.com Signed-off-by: Palmer Dabbelt