* [PATCH v4 0/2] add Microchip PIT64B timer @ 2019-12-13 11:19 ` Claudiu Beznea 0 siblings, 0 replies; 9+ messages in thread From: Claudiu Beznea @ 2019-12-13 11:19 UTC (permalink / raw) To: robh+dt, mark.rutland, nicolas.ferre, alexandre.belloni, ludovic.desroches, daniel.lezcano, tglx Cc: devicetree, linux-arm-kernel, linux-kernel, Claudiu Beznea Hi, This series adds driver for Microchip PIT64B timer. Timer could be used in continuous or oneshot mode. It has 2x32 bit registers to emulate a 64 bit timer. The timer's period could be configured via LSB_PR and MSB_PR registers. The current timer's value could be checked via TLSB and TMSB registers. When (TMSB << 32) | TLSB value reach the (MSB_PR << 32) | LSB_PR interrupt is raised. If in contiuous mode the TLSB and TMSB resets and restart counting. This drivers uses PIT64B capabilities for clocksource and clockevent. The first requested PIT64B timer is used for clockevent. The second one is used for clocksource. Individual PIT64B hardware resources were used for clocksource and clockevent to be able to support high resolution timers with this PIT64B implementation. Thank you, Claudiu Beznea Changes in v4: - use clocksource_mmio_init() to register timer for clocksource functionality; with this, struct mchp_pit64b_clksrc was removed and replaced with mchp_pit64b_cs_base variable to keep the timer base address - removed clksrc_to_mchp_pit64b_timer() macro - introduce mchp_pit64b_dt_init_timer() and add there the content of mchp_pit64b_timer_init() which was removed - s/mchp_pit64b_dt_init_clksrc()/mchp_pit64b_init_clksrc(), s/mchp_pit64b_dt_init_clkevt()/mchp_pit64b_init_clkevt() and minimize their content - remove cycles member from mchp_pit64b_timer and add it as a local variable (to be used only for clockevent timer in periodic mode) - add mode member to struct mchp_pit64b_timer keeping a precomputed value (at probe) of the mode register to remove some of the logic inside mchp_pit64b_reset() function - remove irq member from struct mchp_pit64b_timer; add it instead as argument for mchp_pit64b_reset() function to be able to use the same function also for programming of clocksource timer - remove mchp_pit64b_clkevt_set_oneshot() function; timer programming while in one shot mode should be done by mchp_pit64b_clkevt_set_next_event() - in mchp_pit64b_clkevt_suspend()/mchp_pit64b_clkevt_resume() remove the timer reconfiguration (via mchp_pit64b_reset()); it should be done while programming next delta (if one shot mode) or in mchp_pit64b_clkevt_set_periodic() if periodic mode - s/mchp_pit64b_get_period()/mchp_pit64b_cnt_read() - in mchp_pit64b_init_clksrc() stop timer if clocksource registration fails - remove MCHP_PIT64B_ISR_PERIOD macro - s/to_mchp_pit64b_clkevt()/to_mchp_pit64b_timer() and cast the result to struct mchp_pit64b_timer * - s/mchp_pit64b_pres_prepare()/mchp_pit64b_init_mode() since the function will be in charge of precomputing the mode registe value to be used at runtime Changes in v3: - rework data structures: - timer related data structure is called now mchp_pit64b_timer embedding base iomem, clocks, interrupt, prescaler value - introduced struct mchp_pit64b_clksrc and struct mchp_pit64b_clkevt instead of mchp_pit64b_clksrc_data and mchp_pit64b_clkevt_data - use container_of() to retrieve mchp_pit64b_timer objects on clocksource/clockevent specific APIs - document data structures - use raw_local_irq_save()/raw_local_irq_restore() when reading MCHP_PIT64B_TLSBR and MCHP_PIT64B_TMSBR in mchp_pit64b_get_period() - get rid of mchp_pit64b_read(), mchp_pit64b_write() and use instead readl_relaxed(), writel_relaxed() - get rid of mchp_pit64b_set_period() and inlined its instructions in mchp_pit64b_reset() - mchp_pit64b_reset() gets now as arguments an object of type struct mchp_pit64b_timer, cycles to program and mode - remove static struct clocksource mchp_pit64b_clksrc and static struct clock_event_device mchp_pit64b_clkevt and instead allocate and fill them in mchp_pit64b_dt_init_clksrc() and mchp_pit64b_dt_init_clkevt() - call mchp_pit64b_reset() in mchp_pit64b_clkevt_set_next_event() and program clockevent timer with SMOD=0; if SMOD=1 the timer's period could be reprogrammed also if writing TLSB, TMSB if it is running. In cases were its period expired START bit still has to be set in control register. In case the programming sequence is like in v2, with SMOD=1: - program MSB_PR - program LSB_PR - program START bit in control register for short programmed periods we may start the timer twice with this programming sequence, 1st time after LSB_PR is updated (and due to SMOD=1), 2nd time after programming START bit in control register and in case programmed period already expire - simplify mchp_pit64b_interrupt() by just reading ISR register, to clear the received interrupt, and just call irq_data->clkevt->event_handler(irq_data->clkevt); - in mchp_pit64b_pres_compute() chose the bigest prescaler in case a good one not found - document mchp_pit64b_pres_prepare() and simplified it a bit - enforce gclk as mandatory - introduce mchp_pit64b_timer_init() and mchp_pit64b_timer_cleanup() - keep the clocksource timer base address in a mchp_pit64b_cs_base variable so that it could be used by mchp_pit64b_sched_read_clk() - rework mchp_pit64b_dt_init() and return -EINVAL in case it was called more than two times: one for initialization of clockevent, one for initialization of clocksource - introduce MCHP_PIT64B_MR_ONE_SHOT define - move the new lines introduced in Makefile and Kconfig at the end of files - collect Rob's Reviewed-by tag on patch 1/2 - review the commit message of patch 2/2 Changes in v2: - remove clock-frequency DT binding and hardcoded it in the driver - initialize best_pres variable in mchp_pit64b_pres_prepare() - remove MCHP_PIT64B_DEF_FREQ - get rid of patches 3-5 from v1 [1] since there is no entry in MAINTAINERS file for this entry. It was removed in commit 44015a8181a5 ("MAINTAINERS: at91: remove the TC entry") [1] https://lore.kernel.org/lkml/1552580772-8499-1-git-send-email-claudiu.beznea@microchip.com/ Claudiu Beznea (2): dt-bindings: arm: atmel: add bindings for PIT64B clocksource/drivers/timer-microchip-pit64b: add Microchip PIT64B support .../devicetree/bindings/arm/atmel-sysregs.txt | 6 + drivers/clocksource/Kconfig | 7 + drivers/clocksource/Makefile | 1 + drivers/clocksource/timer-microchip-pit64b.c | 449 +++++++++++++++++++++ 4 files changed, 463 insertions(+) create mode 100644 drivers/clocksource/timer-microchip-pit64b.c -- 2.7.4 ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v4 0/2] add Microchip PIT64B timer @ 2019-12-13 11:19 ` Claudiu Beznea 0 siblings, 0 replies; 9+ messages in thread From: Claudiu Beznea @ 2019-12-13 11:19 UTC (permalink / raw) To: robh+dt, mark.rutland, nicolas.ferre, alexandre.belloni, ludovic.desroches, daniel.lezcano, tglx Cc: devicetree, linux-kernel, linux-arm-kernel, Claudiu Beznea Hi, This series adds driver for Microchip PIT64B timer. Timer could be used in continuous or oneshot mode. It has 2x32 bit registers to emulate a 64 bit timer. The timer's period could be configured via LSB_PR and MSB_PR registers. The current timer's value could be checked via TLSB and TMSB registers. When (TMSB << 32) | TLSB value reach the (MSB_PR << 32) | LSB_PR interrupt is raised. If in contiuous mode the TLSB and TMSB resets and restart counting. This drivers uses PIT64B capabilities for clocksource and clockevent. The first requested PIT64B timer is used for clockevent. The second one is used for clocksource. Individual PIT64B hardware resources were used for clocksource and clockevent to be able to support high resolution timers with this PIT64B implementation. Thank you, Claudiu Beznea Changes in v4: - use clocksource_mmio_init() to register timer for clocksource functionality; with this, struct mchp_pit64b_clksrc was removed and replaced with mchp_pit64b_cs_base variable to keep the timer base address - removed clksrc_to_mchp_pit64b_timer() macro - introduce mchp_pit64b_dt_init_timer() and add there the content of mchp_pit64b_timer_init() which was removed - s/mchp_pit64b_dt_init_clksrc()/mchp_pit64b_init_clksrc(), s/mchp_pit64b_dt_init_clkevt()/mchp_pit64b_init_clkevt() and minimize their content - remove cycles member from mchp_pit64b_timer and add it as a local variable (to be used only for clockevent timer in periodic mode) - add mode member to struct mchp_pit64b_timer keeping a precomputed value (at probe) of the mode register to remove some of the logic inside mchp_pit64b_reset() function - remove irq member from struct mchp_pit64b_timer; add it instead as argument for mchp_pit64b_reset() function to be able to use the same function also for programming of clocksource timer - remove mchp_pit64b_clkevt_set_oneshot() function; timer programming while in one shot mode should be done by mchp_pit64b_clkevt_set_next_event() - in mchp_pit64b_clkevt_suspend()/mchp_pit64b_clkevt_resume() remove the timer reconfiguration (via mchp_pit64b_reset()); it should be done while programming next delta (if one shot mode) or in mchp_pit64b_clkevt_set_periodic() if periodic mode - s/mchp_pit64b_get_period()/mchp_pit64b_cnt_read() - in mchp_pit64b_init_clksrc() stop timer if clocksource registration fails - remove MCHP_PIT64B_ISR_PERIOD macro - s/to_mchp_pit64b_clkevt()/to_mchp_pit64b_timer() and cast the result to struct mchp_pit64b_timer * - s/mchp_pit64b_pres_prepare()/mchp_pit64b_init_mode() since the function will be in charge of precomputing the mode registe value to be used at runtime Changes in v3: - rework data structures: - timer related data structure is called now mchp_pit64b_timer embedding base iomem, clocks, interrupt, prescaler value - introduced struct mchp_pit64b_clksrc and struct mchp_pit64b_clkevt instead of mchp_pit64b_clksrc_data and mchp_pit64b_clkevt_data - use container_of() to retrieve mchp_pit64b_timer objects on clocksource/clockevent specific APIs - document data structures - use raw_local_irq_save()/raw_local_irq_restore() when reading MCHP_PIT64B_TLSBR and MCHP_PIT64B_TMSBR in mchp_pit64b_get_period() - get rid of mchp_pit64b_read(), mchp_pit64b_write() and use instead readl_relaxed(), writel_relaxed() - get rid of mchp_pit64b_set_period() and inlined its instructions in mchp_pit64b_reset() - mchp_pit64b_reset() gets now as arguments an object of type struct mchp_pit64b_timer, cycles to program and mode - remove static struct clocksource mchp_pit64b_clksrc and static struct clock_event_device mchp_pit64b_clkevt and instead allocate and fill them in mchp_pit64b_dt_init_clksrc() and mchp_pit64b_dt_init_clkevt() - call mchp_pit64b_reset() in mchp_pit64b_clkevt_set_next_event() and program clockevent timer with SMOD=0; if SMOD=1 the timer's period could be reprogrammed also if writing TLSB, TMSB if it is running. In cases were its period expired START bit still has to be set in control register. In case the programming sequence is like in v2, with SMOD=1: - program MSB_PR - program LSB_PR - program START bit in control register for short programmed periods we may start the timer twice with this programming sequence, 1st time after LSB_PR is updated (and due to SMOD=1), 2nd time after programming START bit in control register and in case programmed period already expire - simplify mchp_pit64b_interrupt() by just reading ISR register, to clear the received interrupt, and just call irq_data->clkevt->event_handler(irq_data->clkevt); - in mchp_pit64b_pres_compute() chose the bigest prescaler in case a good one not found - document mchp_pit64b_pres_prepare() and simplified it a bit - enforce gclk as mandatory - introduce mchp_pit64b_timer_init() and mchp_pit64b_timer_cleanup() - keep the clocksource timer base address in a mchp_pit64b_cs_base variable so that it could be used by mchp_pit64b_sched_read_clk() - rework mchp_pit64b_dt_init() and return -EINVAL in case it was called more than two times: one for initialization of clockevent, one for initialization of clocksource - introduce MCHP_PIT64B_MR_ONE_SHOT define - move the new lines introduced in Makefile and Kconfig at the end of files - collect Rob's Reviewed-by tag on patch 1/2 - review the commit message of patch 2/2 Changes in v2: - remove clock-frequency DT binding and hardcoded it in the driver - initialize best_pres variable in mchp_pit64b_pres_prepare() - remove MCHP_PIT64B_DEF_FREQ - get rid of patches 3-5 from v1 [1] since there is no entry in MAINTAINERS file for this entry. It was removed in commit 44015a8181a5 ("MAINTAINERS: at91: remove the TC entry") [1] https://lore.kernel.org/lkml/1552580772-8499-1-git-send-email-claudiu.beznea@microchip.com/ Claudiu Beznea (2): dt-bindings: arm: atmel: add bindings for PIT64B clocksource/drivers/timer-microchip-pit64b: add Microchip PIT64B support .../devicetree/bindings/arm/atmel-sysregs.txt | 6 + drivers/clocksource/Kconfig | 7 + drivers/clocksource/Makefile | 1 + drivers/clocksource/timer-microchip-pit64b.c | 449 +++++++++++++++++++++ 4 files changed, 463 insertions(+) create mode 100644 drivers/clocksource/timer-microchip-pit64b.c -- 2.7.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v4 1/2] dt-bindings: arm: atmel: add bindings for PIT64B 2019-12-13 11:19 ` Claudiu Beznea @ 2019-12-13 11:19 ` Claudiu Beznea -1 siblings, 0 replies; 9+ messages in thread From: Claudiu Beznea @ 2019-12-13 11:19 UTC (permalink / raw) To: robh+dt, mark.rutland, nicolas.ferre, alexandre.belloni, ludovic.desroches, daniel.lezcano, tglx Cc: devicetree, linux-arm-kernel, linux-kernel, Claudiu Beznea Add device tree bindings for PIT64B timer. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Reviewed-by: Rob Herring <robh@kernel.org> --- Documentation/devicetree/bindings/arm/atmel-sysregs.txt | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/devicetree/bindings/arm/atmel-sysregs.txt b/Documentation/devicetree/bindings/arm/atmel-sysregs.txt index 9fbde401a090..e003a553b986 100644 --- a/Documentation/devicetree/bindings/arm/atmel-sysregs.txt +++ b/Documentation/devicetree/bindings/arm/atmel-sysregs.txt @@ -10,6 +10,12 @@ PIT Timer required properties: - interrupts: Should contain interrupt for the PIT which is the IRQ line shared across all System Controller members. +PIT64B Timer required properties: +- compatible: Should be "microchip,sam9x60-pit64b" +- reg: Should contain registers location and length +- interrupts: Should contain interrupt for PIT64B timer +- clocks: Should contain the available clock sources for PIT64B timer. + System Timer (ST) required properties: - compatible: Should be "atmel,at91rm9200-st", "syscon", "simple-mfd" - reg: Should contain registers location and length -- 2.7.4 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH v4 1/2] dt-bindings: arm: atmel: add bindings for PIT64B @ 2019-12-13 11:19 ` Claudiu Beznea 0 siblings, 0 replies; 9+ messages in thread From: Claudiu Beznea @ 2019-12-13 11:19 UTC (permalink / raw) To: robh+dt, mark.rutland, nicolas.ferre, alexandre.belloni, ludovic.desroches, daniel.lezcano, tglx Cc: devicetree, linux-kernel, linux-arm-kernel, Claudiu Beznea Add device tree bindings for PIT64B timer. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Reviewed-by: Rob Herring <robh@kernel.org> --- Documentation/devicetree/bindings/arm/atmel-sysregs.txt | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/devicetree/bindings/arm/atmel-sysregs.txt b/Documentation/devicetree/bindings/arm/atmel-sysregs.txt index 9fbde401a090..e003a553b986 100644 --- a/Documentation/devicetree/bindings/arm/atmel-sysregs.txt +++ b/Documentation/devicetree/bindings/arm/atmel-sysregs.txt @@ -10,6 +10,12 @@ PIT Timer required properties: - interrupts: Should contain interrupt for the PIT which is the IRQ line shared across all System Controller members. +PIT64B Timer required properties: +- compatible: Should be "microchip,sam9x60-pit64b" +- reg: Should contain registers location and length +- interrupts: Should contain interrupt for PIT64B timer +- clocks: Should contain the available clock sources for PIT64B timer. + System Timer (ST) required properties: - compatible: Should be "atmel,at91rm9200-st", "syscon", "simple-mfd" - reg: Should contain registers location and length -- 2.7.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH v4 2/2] clocksource/drivers/timer-microchip-pit64b: add Microchip PIT64B support 2019-12-13 11:19 ` Claudiu Beznea @ 2019-12-13 11:19 ` Claudiu Beznea -1 siblings, 0 replies; 9+ messages in thread From: Claudiu Beznea @ 2019-12-13 11:19 UTC (permalink / raw) To: robh+dt, mark.rutland, nicolas.ferre, alexandre.belloni, ludovic.desroches, daniel.lezcano, tglx Cc: devicetree, linux-arm-kernel, linux-kernel, Claudiu Beznea Add driver for Microchip PIT64B timer. Timer could be used in continuous mode or oneshot mode. The hardware has 2x32 bit registers for period emulating a 64 bit timer. The LSB_PR and MSB_PR registers are used to set the period value (compare value). TLSB and TMSB keeps the current value of the counter. After a compare the TLSB and TMSB register resets. The driver uses PIT64B timer for clocksource or clockevent. First requested timer would be registered as clockevent, second one would be registered as clocksource. Individual PIT64B hardware resources were used for clocksource and clockevent to be able to support high resolution timers with this hardware implementation. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> --- drivers/clocksource/Kconfig | 7 + drivers/clocksource/Makefile | 1 + drivers/clocksource/timer-microchip-pit64b.c | 449 +++++++++++++++++++++++++++ 3 files changed, 457 insertions(+) create mode 100644 drivers/clocksource/timer-microchip-pit64b.c diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 5fdd76cb1768..6c3907b54c65 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -697,4 +697,11 @@ config INGENIC_TIMER help Support for the timer/counter unit of the Ingenic JZ SoCs. +config MICROCHIP_PIT64B + bool "Microchip PIT64B support" + depends on OF || COMPILE_TEST + select CLKSRC_MMIO + help + This option enables Microchip PIT64B timer. + endmenu diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 4dfe4225ece7..713686faa549 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -88,3 +88,4 @@ obj-$(CONFIG_RISCV_TIMER) += timer-riscv.o obj-$(CONFIG_CSKY_MP_TIMER) += timer-mp-csky.o obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o obj-$(CONFIG_HYPERV_TIMER) += hyperv_timer.o +obj-$(CONFIG_MICROCHIP_PIT64B) += timer-microchip-pit64b.o diff --git a/drivers/clocksource/timer-microchip-pit64b.c b/drivers/clocksource/timer-microchip-pit64b.c new file mode 100644 index 000000000000..27a389a7e078 --- /dev/null +++ b/drivers/clocksource/timer-microchip-pit64b.c @@ -0,0 +1,449 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 64-bit Periodic Interval Timer driver + * + * Copyright (C) 2019 Microchip Technology Inc. and its subsidiaries + * + * Author: Claudiu Beznea <claudiu.beznea@microchip.com> + */ + +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/sched_clock.h> +#include <linux/slab.h> + +#define MCHP_PIT64B_CR 0x00 /* Control Register */ +#define MCHP_PIT64B_CR_START BIT(0) +#define MCHP_PIT64B_CR_SWRST BIT(8) + +#define MCHP_PIT64B_MR 0x04 /* Mode Register */ +#define MCHP_PIT64B_MR_CONT BIT(0) +#define MCHP_PIT64B_MR_ONE_SHOT (0) +#define MCHP_PIT64B_MR_SGCLK BIT(3) +#define MCHP_PIT64B_MR_PRES GENMASK(11, 8) + +#define MCHP_PIT64B_LSB_PR 0x08 /* LSB Period Register */ + +#define MCHP_PIT64B_MSB_PR 0x0C /* MSB Period Register */ + +#define MCHP_PIT64B_IER 0x10 /* Interrupt Enable Register */ +#define MCHP_PIT64B_IER_PERIOD BIT(0) + +#define MCHP_PIT64B_ISR 0x1C /* Interrupt Status Register */ + +#define MCHP_PIT64B_TLSBR 0x20 /* Timer LSB Register */ + +#define MCHP_PIT64B_TMSBR 0x24 /* Timer MSB Register */ + +#define MCHP_PIT64B_PRES_MAX 0x10 +#define MCHP_PIT64B_LSBMASK GENMASK_ULL(31, 0) +#define MCHP_PIT64B_PRES_TO_MODE(p) (MCHP_PIT64B_MR_PRES & ((p) << 8)) +#define MCHP_PIT64B_MODE_TO_PRES(m) ((MCHP_PIT64B_MR_PRES & (m)) >> 8) +#define MCHP_PIT64B_DEF_CS_FREQ 5000000UL /* 5 MHz */ +#define MCHP_PIT64B_DEF_CE_FREQ 32768 /* 32 KHz */ + +#define MCHP_PIT64B_NAME "pit64b" + +/** + * struct mchp_pit64b_timer - PIT64B timer data structure + * @base: base address of PIT64B hardware block + * @pclk: PIT64B's peripheral clock + * @gclk: PIT64B's generic clock + * @mode: precomputed value for mode register + */ +struct mchp_pit64b_timer { + void __iomem *base; + struct clk *pclk; + struct clk *gclk; + u32 mode; +}; + +/** + * mchp_pit64b_clkevt - PIT64B clockevent data structure + * @timer: PIT64B timer + * @clkevt: clockevent + */ +struct mchp_pit64b_clkevt { + struct mchp_pit64b_timer timer; + struct clock_event_device clkevt; +}; + +#define to_mchp_pit64b_timer(x) \ + ((struct mchp_pit64b_timer *)container_of(x,\ + struct mchp_pit64b_clkevt, clkevt)) + +/* Base address for clocksource timer. */ +static void __iomem *mchp_pit64b_cs_base; +/* Default cycles for clockevent timer. */ +static u64 mchp_pit64b_ce_cycles; + +static inline u64 mchp_pit64b_cnt_read(void __iomem *base) +{ + unsigned long flags; + u32 low, high; + + raw_local_irq_save(flags); + + /* + * When using a 64 bit period TLSB must be read first, followed by the + * read of TMSB. This sequence generates an atomic read of the 64 bit + * timer value whatever the lapse of time between the accesses. + */ + low = readl_relaxed(base + MCHP_PIT64B_TLSBR); + high = readl_relaxed(base + MCHP_PIT64B_TMSBR); + + raw_local_irq_restore(flags); + + return (((u64)high << 32) | low); +} + +static inline void mchp_pit64b_reset(struct mchp_pit64b_timer *timer, + u64 cycles, u32 mode, u32 irqs) +{ + u32 low, high; + + low = cycles & MCHP_PIT64B_LSBMASK; + high = cycles >> 32; + + writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR); + writel_relaxed(mode | timer->mode, timer->base + MCHP_PIT64B_MR); + writel_relaxed(high, timer->base + MCHP_PIT64B_MSB_PR); + writel_relaxed(low, timer->base + MCHP_PIT64B_LSB_PR); + writel_relaxed(irqs, timer->base + MCHP_PIT64B_IER); + writel_relaxed(MCHP_PIT64B_CR_START, timer->base + MCHP_PIT64B_CR); +} + +static u64 mchp_pit64b_clksrc_read(struct clocksource *cs) +{ + return mchp_pit64b_cnt_read(mchp_pit64b_cs_base); +} + +static u64 mchp_pit64b_sched_read_clk(void) +{ + return mchp_pit64b_cnt_read(mchp_pit64b_cs_base); +} + +static int mchp_pit64b_clkevt_shutdown(struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR); + + return 0; +} + +static int mchp_pit64b_clkevt_set_periodic(struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + mchp_pit64b_reset(timer, mchp_pit64b_ce_cycles, MCHP_PIT64B_MR_CONT, + MCHP_PIT64B_IER_PERIOD); + + return 0; +} + +static int mchp_pit64b_clkevt_set_next_event(unsigned long evt, + struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + mchp_pit64b_reset(timer, evt, MCHP_PIT64B_MR_ONE_SHOT, + MCHP_PIT64B_IER_PERIOD); + + return 0; +} + +static void mchp_pit64b_clkevt_suspend(struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR); + if (timer->mode & MCHP_PIT64B_MR_SGCLK) + clk_disable_unprepare(timer->gclk); + clk_disable_unprepare(timer->pclk); +} + +static void mchp_pit64b_clkevt_resume(struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + clk_prepare_enable(timer->pclk); + if (timer->mode & MCHP_PIT64B_MR_SGCLK) + clk_prepare_enable(timer->gclk); +} + +static irqreturn_t mchp_pit64b_interrupt(int irq, void *dev_id) +{ + struct mchp_pit64b_clkevt *irq_data = dev_id; + + /* Need to clear the interrupt. */ + readl_relaxed(irq_data->timer.base + MCHP_PIT64B_ISR); + + irq_data->clkevt.event_handler(&irq_data->clkevt); + + return IRQ_HANDLED; +} + +static void __init mchp_pit64b_pres_compute(u32 *pres, u32 clk_rate, + u32 max_rate) +{ + u32 tmp; + + for (*pres = 0; *pres < MCHP_PIT64B_PRES_MAX; (*pres)++) { + tmp = clk_rate / (*pres + 1); + if (tmp <= max_rate) + break; + } + + /* Use the bigest prescaler if we didn't match one. */ + if (*pres == MCHP_PIT64B_PRES_MAX) + *pres = MCHP_PIT64B_PRES_MAX - 1; +} + +/** + * mchp_pit64b_init_mode - prepare PIT64B mode register value to be used at + * runtime; this includes prescaler and SGCLK bit + * + * PIT64B timer may be fed by gclk or pclk. When gclk is used its rate has to + * be at least 3 times lower that pclk's rate. pclk rate is fixed, gclk rate + * could be changed via clock APIs. The chosen clock (pclk or gclk) could be + * divided by the internal PIT64B's divider. + * + * This function, first tries to use GCLK by requesting the desired rate from + * PMC and then using the internal PIT64B prescaler, if any, to reach the + * requested rate. If PCLK/GCLK < 3 (condition requested by PIT64B hardware) + * then the function falls back on using PCLK as clock source for PIT64B timer + * choosing the highest prescaler in case it doesn't locate one to match the + * requested frequency. + * + * Below is presented the PIT64B block in relation with PMC: + * + * PIT64B + * PMC +------------------------------------+ + * +----+ | +-----+ | + * | |-->gclk -->|-->| | +---------+ +-----+ | + * | | | | MUX |--->| Divider |->|timer| | + * | |-->pclk -->|-->| | +---------+ +-----+ | + * +----+ | +-----+ | + * | ^ | + * | sel | + * +------------------------------------+ + * + * Where: + * - gclk rate <= pclk rate/3 + * - gclk rate could be requested from PMC + * - pclk rate is fixed (cannot be requested from PMC) + */ +static int __init mchp_pit64b_init_mode(struct mchp_pit64b_timer *timer, + unsigned long max_rate) +{ + unsigned long pclk_rate, diff = 0, best_diff = ULONG_MAX; + long gclk_round = 0; + u32 pres, best_pres = 0; + + pclk_rate = clk_get_rate(timer->pclk); + if (!pclk_rate) + return -EINVAL; + + /* Try using GCLK. */ + gclk_round = clk_round_rate(timer->gclk, max_rate); + if (gclk_round < 0) + goto pclk; + + if (pclk_rate / gclk_round < 3) + goto pclk; + + mchp_pit64b_pres_compute(&pres, gclk_round, max_rate); + best_diff = abs(gclk_round / (pres + 1) - max_rate); + best_pres = pres; + + if (!best_diff) { + timer->mode |= MCHP_PIT64B_MR_SGCLK; + goto done; + } + +pclk: + /* Check if requested rate could be obtained using PCLK. */ + mchp_pit64b_pres_compute(&pres, pclk_rate, max_rate); + diff = abs(pclk_rate / (pres + 1) - max_rate); + + if (best_diff > diff) { + /* Use PCLK. */ + best_pres = pres; + } else { + /* Use GCLK. */ + timer->mode |= MCHP_PIT64B_MR_SGCLK; + clk_set_rate(timer->gclk, gclk_round); + } + +done: + timer->mode |= MCHP_PIT64B_PRES_TO_MODE(best_pres); + + pr_info("PIT64B: using clk=%s with prescaler %u, freq=%lu [Hz]\n", + timer->mode & MCHP_PIT64B_MR_SGCLK ? "gclk" : "pclk", best_pres, + timer->mode & MCHP_PIT64B_MR_SGCLK ? + gclk_round / (best_pres + 1) : pclk_rate / (best_pres + 1)); + + return 0; +} + +static int __init mchp_pit64b_init_clksrc(struct mchp_pit64b_timer *timer, + u32 clk_rate) +{ + int ret; + + mchp_pit64b_reset(timer, ULLONG_MAX, MCHP_PIT64B_MR_CONT, 0); + + mchp_pit64b_cs_base = timer->base; + + ret = clocksource_mmio_init(timer->base, MCHP_PIT64B_NAME, clk_rate, + 210, 64, mchp_pit64b_clksrc_read); + if (ret) { + pr_debug("clksrc: Failed to register PIT64B clocksource!\n"); + + /* Stop timer. */ + writel_relaxed(MCHP_PIT64B_CR_SWRST, + timer->base + MCHP_PIT64B_CR); + + return ret; + } + + sched_clock_register(mchp_pit64b_sched_read_clk, 64, clk_rate); + + return 0; +} + +static int __init mchp_pit64b_init_clkevt(struct mchp_pit64b_timer *timer, + u32 clk_rate, u32 irq) +{ + struct mchp_pit64b_clkevt *ce; + int ret; + + ce = kzalloc(sizeof(*ce), GFP_KERNEL); + if (!ce) + return -ENOMEM; + + mchp_pit64b_ce_cycles = DIV_ROUND_CLOSEST(clk_rate, HZ); + + ce->timer.base = timer->base; + ce->timer.pclk = timer->pclk; + ce->timer.gclk = timer->gclk; + ce->timer.mode = timer->mode; + ce->clkevt.name = MCHP_PIT64B_NAME; + ce->clkevt.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC; + ce->clkevt.rating = 150; + ce->clkevt.set_state_shutdown = mchp_pit64b_clkevt_shutdown; + ce->clkevt.set_state_periodic = mchp_pit64b_clkevt_set_periodic; + ce->clkevt.set_next_event = mchp_pit64b_clkevt_set_next_event; + ce->clkevt.suspend = mchp_pit64b_clkevt_suspend; + ce->clkevt.resume = mchp_pit64b_clkevt_resume; + ce->clkevt.cpumask = cpumask_of(0); + ce->clkevt.irq = irq; + + ret = request_irq(irq, mchp_pit64b_interrupt, IRQF_TIMER, + "pit64b_tick", ce); + if (ret) { + pr_debug("clkevt: Failed to setup PIT64B IRQ\n"); + kfree(ce); + return ret; + } + + clockevents_config_and_register(&ce->clkevt, clk_rate, 1, ULONG_MAX); + + return 0; +} + +static int __init mchp_pit64b_dt_init_timer(struct device_node *node, + bool clkevt) +{ + u32 freq = clkevt ? MCHP_PIT64B_DEF_CE_FREQ : MCHP_PIT64B_DEF_CS_FREQ; + struct mchp_pit64b_timer timer = { 0 }; + unsigned long clk_rate; + u32 irq = 0; + int ret; + + /* Parse DT node. */ + timer.pclk = of_clk_get_by_name(node, "pclk"); + if (IS_ERR(timer.pclk)) + return PTR_ERR(timer.pclk); + + timer.gclk = of_clk_get_by_name(node, "gclk"); + if (IS_ERR(timer.gclk)) + return PTR_ERR(timer.gclk); + + timer.base = of_iomap(node, 0); + if (!timer.base) + return -ENXIO; + + if (clkevt) { + irq = irq_of_parse_and_map(node, 0); + if (!irq) { + ret = -ENODEV; + goto io_unmap; + } + } + + /* Initialize mode (prescaler + SGCK bit). To be used at runtime. */ + ret = mchp_pit64b_init_mode(&timer, freq); + if (ret) + goto irq_unmap; + + ret = clk_prepare_enable(timer.pclk); + if (ret) + goto irq_unmap; + + if (timer.mode & MCHP_PIT64B_MR_SGCLK) { + ret = clk_prepare_enable(timer.gclk); + if (ret) + goto pclk_unprepare; + + clk_rate = clk_get_rate(timer.gclk); + } else { + clk_rate = clk_get_rate(timer.pclk); + } + clk_rate = clk_rate / (MCHP_PIT64B_MODE_TO_PRES(timer.mode) + 1); + + if (clkevt) + ret = mchp_pit64b_init_clkevt(&timer, clk_rate, irq); + else + ret = mchp_pit64b_init_clksrc(&timer, clk_rate); + + if (ret) + goto gclk_unprepare; + + return 0; + +gclk_unprepare: + if (timer.mode & MCHP_PIT64B_MR_SGCLK) + clk_disable_unprepare(timer.gclk); +pclk_unprepare: + clk_disable_unprepare(timer.pclk); +irq_unmap: + irq_dispose_mapping(irq); +io_unmap: + iounmap(timer.base); + + return ret; +} + +static int __init mchp_pit64b_dt_init(struct device_node *node) +{ + static int inits; + + switch (inits++) { + case 0: + /* 1st request, register clockevent. */ + return mchp_pit64b_dt_init_timer(node, true); + case 1: + /* 2nd request, register clocksource. */ + return mchp_pit64b_dt_init_timer(node, false); + } + + /* The rest, don't care. */ + return -EINVAL; +} + +TIMER_OF_DECLARE(mchp_pit64b, "microchip,sam9x60-pit64b", mchp_pit64b_dt_init); -- 2.7.4 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH v4 2/2] clocksource/drivers/timer-microchip-pit64b: add Microchip PIT64B support @ 2019-12-13 11:19 ` Claudiu Beznea 0 siblings, 0 replies; 9+ messages in thread From: Claudiu Beznea @ 2019-12-13 11:19 UTC (permalink / raw) To: robh+dt, mark.rutland, nicolas.ferre, alexandre.belloni, ludovic.desroches, daniel.lezcano, tglx Cc: devicetree, linux-kernel, linux-arm-kernel, Claudiu Beznea Add driver for Microchip PIT64B timer. Timer could be used in continuous mode or oneshot mode. The hardware has 2x32 bit registers for period emulating a 64 bit timer. The LSB_PR and MSB_PR registers are used to set the period value (compare value). TLSB and TMSB keeps the current value of the counter. After a compare the TLSB and TMSB register resets. The driver uses PIT64B timer for clocksource or clockevent. First requested timer would be registered as clockevent, second one would be registered as clocksource. Individual PIT64B hardware resources were used for clocksource and clockevent to be able to support high resolution timers with this hardware implementation. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> --- drivers/clocksource/Kconfig | 7 + drivers/clocksource/Makefile | 1 + drivers/clocksource/timer-microchip-pit64b.c | 449 +++++++++++++++++++++++++++ 3 files changed, 457 insertions(+) create mode 100644 drivers/clocksource/timer-microchip-pit64b.c diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 5fdd76cb1768..6c3907b54c65 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -697,4 +697,11 @@ config INGENIC_TIMER help Support for the timer/counter unit of the Ingenic JZ SoCs. +config MICROCHIP_PIT64B + bool "Microchip PIT64B support" + depends on OF || COMPILE_TEST + select CLKSRC_MMIO + help + This option enables Microchip PIT64B timer. + endmenu diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 4dfe4225ece7..713686faa549 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -88,3 +88,4 @@ obj-$(CONFIG_RISCV_TIMER) += timer-riscv.o obj-$(CONFIG_CSKY_MP_TIMER) += timer-mp-csky.o obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o obj-$(CONFIG_HYPERV_TIMER) += hyperv_timer.o +obj-$(CONFIG_MICROCHIP_PIT64B) += timer-microchip-pit64b.o diff --git a/drivers/clocksource/timer-microchip-pit64b.c b/drivers/clocksource/timer-microchip-pit64b.c new file mode 100644 index 000000000000..27a389a7e078 --- /dev/null +++ b/drivers/clocksource/timer-microchip-pit64b.c @@ -0,0 +1,449 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 64-bit Periodic Interval Timer driver + * + * Copyright (C) 2019 Microchip Technology Inc. and its subsidiaries + * + * Author: Claudiu Beznea <claudiu.beznea@microchip.com> + */ + +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/sched_clock.h> +#include <linux/slab.h> + +#define MCHP_PIT64B_CR 0x00 /* Control Register */ +#define MCHP_PIT64B_CR_START BIT(0) +#define MCHP_PIT64B_CR_SWRST BIT(8) + +#define MCHP_PIT64B_MR 0x04 /* Mode Register */ +#define MCHP_PIT64B_MR_CONT BIT(0) +#define MCHP_PIT64B_MR_ONE_SHOT (0) +#define MCHP_PIT64B_MR_SGCLK BIT(3) +#define MCHP_PIT64B_MR_PRES GENMASK(11, 8) + +#define MCHP_PIT64B_LSB_PR 0x08 /* LSB Period Register */ + +#define MCHP_PIT64B_MSB_PR 0x0C /* MSB Period Register */ + +#define MCHP_PIT64B_IER 0x10 /* Interrupt Enable Register */ +#define MCHP_PIT64B_IER_PERIOD BIT(0) + +#define MCHP_PIT64B_ISR 0x1C /* Interrupt Status Register */ + +#define MCHP_PIT64B_TLSBR 0x20 /* Timer LSB Register */ + +#define MCHP_PIT64B_TMSBR 0x24 /* Timer MSB Register */ + +#define MCHP_PIT64B_PRES_MAX 0x10 +#define MCHP_PIT64B_LSBMASK GENMASK_ULL(31, 0) +#define MCHP_PIT64B_PRES_TO_MODE(p) (MCHP_PIT64B_MR_PRES & ((p) << 8)) +#define MCHP_PIT64B_MODE_TO_PRES(m) ((MCHP_PIT64B_MR_PRES & (m)) >> 8) +#define MCHP_PIT64B_DEF_CS_FREQ 5000000UL /* 5 MHz */ +#define MCHP_PIT64B_DEF_CE_FREQ 32768 /* 32 KHz */ + +#define MCHP_PIT64B_NAME "pit64b" + +/** + * struct mchp_pit64b_timer - PIT64B timer data structure + * @base: base address of PIT64B hardware block + * @pclk: PIT64B's peripheral clock + * @gclk: PIT64B's generic clock + * @mode: precomputed value for mode register + */ +struct mchp_pit64b_timer { + void __iomem *base; + struct clk *pclk; + struct clk *gclk; + u32 mode; +}; + +/** + * mchp_pit64b_clkevt - PIT64B clockevent data structure + * @timer: PIT64B timer + * @clkevt: clockevent + */ +struct mchp_pit64b_clkevt { + struct mchp_pit64b_timer timer; + struct clock_event_device clkevt; +}; + +#define to_mchp_pit64b_timer(x) \ + ((struct mchp_pit64b_timer *)container_of(x,\ + struct mchp_pit64b_clkevt, clkevt)) + +/* Base address for clocksource timer. */ +static void __iomem *mchp_pit64b_cs_base; +/* Default cycles for clockevent timer. */ +static u64 mchp_pit64b_ce_cycles; + +static inline u64 mchp_pit64b_cnt_read(void __iomem *base) +{ + unsigned long flags; + u32 low, high; + + raw_local_irq_save(flags); + + /* + * When using a 64 bit period TLSB must be read first, followed by the + * read of TMSB. This sequence generates an atomic read of the 64 bit + * timer value whatever the lapse of time between the accesses. + */ + low = readl_relaxed(base + MCHP_PIT64B_TLSBR); + high = readl_relaxed(base + MCHP_PIT64B_TMSBR); + + raw_local_irq_restore(flags); + + return (((u64)high << 32) | low); +} + +static inline void mchp_pit64b_reset(struct mchp_pit64b_timer *timer, + u64 cycles, u32 mode, u32 irqs) +{ + u32 low, high; + + low = cycles & MCHP_PIT64B_LSBMASK; + high = cycles >> 32; + + writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR); + writel_relaxed(mode | timer->mode, timer->base + MCHP_PIT64B_MR); + writel_relaxed(high, timer->base + MCHP_PIT64B_MSB_PR); + writel_relaxed(low, timer->base + MCHP_PIT64B_LSB_PR); + writel_relaxed(irqs, timer->base + MCHP_PIT64B_IER); + writel_relaxed(MCHP_PIT64B_CR_START, timer->base + MCHP_PIT64B_CR); +} + +static u64 mchp_pit64b_clksrc_read(struct clocksource *cs) +{ + return mchp_pit64b_cnt_read(mchp_pit64b_cs_base); +} + +static u64 mchp_pit64b_sched_read_clk(void) +{ + return mchp_pit64b_cnt_read(mchp_pit64b_cs_base); +} + +static int mchp_pit64b_clkevt_shutdown(struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR); + + return 0; +} + +static int mchp_pit64b_clkevt_set_periodic(struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + mchp_pit64b_reset(timer, mchp_pit64b_ce_cycles, MCHP_PIT64B_MR_CONT, + MCHP_PIT64B_IER_PERIOD); + + return 0; +} + +static int mchp_pit64b_clkevt_set_next_event(unsigned long evt, + struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + mchp_pit64b_reset(timer, evt, MCHP_PIT64B_MR_ONE_SHOT, + MCHP_PIT64B_IER_PERIOD); + + return 0; +} + +static void mchp_pit64b_clkevt_suspend(struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR); + if (timer->mode & MCHP_PIT64B_MR_SGCLK) + clk_disable_unprepare(timer->gclk); + clk_disable_unprepare(timer->pclk); +} + +static void mchp_pit64b_clkevt_resume(struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + clk_prepare_enable(timer->pclk); + if (timer->mode & MCHP_PIT64B_MR_SGCLK) + clk_prepare_enable(timer->gclk); +} + +static irqreturn_t mchp_pit64b_interrupt(int irq, void *dev_id) +{ + struct mchp_pit64b_clkevt *irq_data = dev_id; + + /* Need to clear the interrupt. */ + readl_relaxed(irq_data->timer.base + MCHP_PIT64B_ISR); + + irq_data->clkevt.event_handler(&irq_data->clkevt); + + return IRQ_HANDLED; +} + +static void __init mchp_pit64b_pres_compute(u32 *pres, u32 clk_rate, + u32 max_rate) +{ + u32 tmp; + + for (*pres = 0; *pres < MCHP_PIT64B_PRES_MAX; (*pres)++) { + tmp = clk_rate / (*pres + 1); + if (tmp <= max_rate) + break; + } + + /* Use the bigest prescaler if we didn't match one. */ + if (*pres == MCHP_PIT64B_PRES_MAX) + *pres = MCHP_PIT64B_PRES_MAX - 1; +} + +/** + * mchp_pit64b_init_mode - prepare PIT64B mode register value to be used at + * runtime; this includes prescaler and SGCLK bit + * + * PIT64B timer may be fed by gclk or pclk. When gclk is used its rate has to + * be at least 3 times lower that pclk's rate. pclk rate is fixed, gclk rate + * could be changed via clock APIs. The chosen clock (pclk or gclk) could be + * divided by the internal PIT64B's divider. + * + * This function, first tries to use GCLK by requesting the desired rate from + * PMC and then using the internal PIT64B prescaler, if any, to reach the + * requested rate. If PCLK/GCLK < 3 (condition requested by PIT64B hardware) + * then the function falls back on using PCLK as clock source for PIT64B timer + * choosing the highest prescaler in case it doesn't locate one to match the + * requested frequency. + * + * Below is presented the PIT64B block in relation with PMC: + * + * PIT64B + * PMC +------------------------------------+ + * +----+ | +-----+ | + * | |-->gclk -->|-->| | +---------+ +-----+ | + * | | | | MUX |--->| Divider |->|timer| | + * | |-->pclk -->|-->| | +---------+ +-----+ | + * +----+ | +-----+ | + * | ^ | + * | sel | + * +------------------------------------+ + * + * Where: + * - gclk rate <= pclk rate/3 + * - gclk rate could be requested from PMC + * - pclk rate is fixed (cannot be requested from PMC) + */ +static int __init mchp_pit64b_init_mode(struct mchp_pit64b_timer *timer, + unsigned long max_rate) +{ + unsigned long pclk_rate, diff = 0, best_diff = ULONG_MAX; + long gclk_round = 0; + u32 pres, best_pres = 0; + + pclk_rate = clk_get_rate(timer->pclk); + if (!pclk_rate) + return -EINVAL; + + /* Try using GCLK. */ + gclk_round = clk_round_rate(timer->gclk, max_rate); + if (gclk_round < 0) + goto pclk; + + if (pclk_rate / gclk_round < 3) + goto pclk; + + mchp_pit64b_pres_compute(&pres, gclk_round, max_rate); + best_diff = abs(gclk_round / (pres + 1) - max_rate); + best_pres = pres; + + if (!best_diff) { + timer->mode |= MCHP_PIT64B_MR_SGCLK; + goto done; + } + +pclk: + /* Check if requested rate could be obtained using PCLK. */ + mchp_pit64b_pres_compute(&pres, pclk_rate, max_rate); + diff = abs(pclk_rate / (pres + 1) - max_rate); + + if (best_diff > diff) { + /* Use PCLK. */ + best_pres = pres; + } else { + /* Use GCLK. */ + timer->mode |= MCHP_PIT64B_MR_SGCLK; + clk_set_rate(timer->gclk, gclk_round); + } + +done: + timer->mode |= MCHP_PIT64B_PRES_TO_MODE(best_pres); + + pr_info("PIT64B: using clk=%s with prescaler %u, freq=%lu [Hz]\n", + timer->mode & MCHP_PIT64B_MR_SGCLK ? "gclk" : "pclk", best_pres, + timer->mode & MCHP_PIT64B_MR_SGCLK ? + gclk_round / (best_pres + 1) : pclk_rate / (best_pres + 1)); + + return 0; +} + +static int __init mchp_pit64b_init_clksrc(struct mchp_pit64b_timer *timer, + u32 clk_rate) +{ + int ret; + + mchp_pit64b_reset(timer, ULLONG_MAX, MCHP_PIT64B_MR_CONT, 0); + + mchp_pit64b_cs_base = timer->base; + + ret = clocksource_mmio_init(timer->base, MCHP_PIT64B_NAME, clk_rate, + 210, 64, mchp_pit64b_clksrc_read); + if (ret) { + pr_debug("clksrc: Failed to register PIT64B clocksource!\n"); + + /* Stop timer. */ + writel_relaxed(MCHP_PIT64B_CR_SWRST, + timer->base + MCHP_PIT64B_CR); + + return ret; + } + + sched_clock_register(mchp_pit64b_sched_read_clk, 64, clk_rate); + + return 0; +} + +static int __init mchp_pit64b_init_clkevt(struct mchp_pit64b_timer *timer, + u32 clk_rate, u32 irq) +{ + struct mchp_pit64b_clkevt *ce; + int ret; + + ce = kzalloc(sizeof(*ce), GFP_KERNEL); + if (!ce) + return -ENOMEM; + + mchp_pit64b_ce_cycles = DIV_ROUND_CLOSEST(clk_rate, HZ); + + ce->timer.base = timer->base; + ce->timer.pclk = timer->pclk; + ce->timer.gclk = timer->gclk; + ce->timer.mode = timer->mode; + ce->clkevt.name = MCHP_PIT64B_NAME; + ce->clkevt.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC; + ce->clkevt.rating = 150; + ce->clkevt.set_state_shutdown = mchp_pit64b_clkevt_shutdown; + ce->clkevt.set_state_periodic = mchp_pit64b_clkevt_set_periodic; + ce->clkevt.set_next_event = mchp_pit64b_clkevt_set_next_event; + ce->clkevt.suspend = mchp_pit64b_clkevt_suspend; + ce->clkevt.resume = mchp_pit64b_clkevt_resume; + ce->clkevt.cpumask = cpumask_of(0); + ce->clkevt.irq = irq; + + ret = request_irq(irq, mchp_pit64b_interrupt, IRQF_TIMER, + "pit64b_tick", ce); + if (ret) { + pr_debug("clkevt: Failed to setup PIT64B IRQ\n"); + kfree(ce); + return ret; + } + + clockevents_config_and_register(&ce->clkevt, clk_rate, 1, ULONG_MAX); + + return 0; +} + +static int __init mchp_pit64b_dt_init_timer(struct device_node *node, + bool clkevt) +{ + u32 freq = clkevt ? MCHP_PIT64B_DEF_CE_FREQ : MCHP_PIT64B_DEF_CS_FREQ; + struct mchp_pit64b_timer timer = { 0 }; + unsigned long clk_rate; + u32 irq = 0; + int ret; + + /* Parse DT node. */ + timer.pclk = of_clk_get_by_name(node, "pclk"); + if (IS_ERR(timer.pclk)) + return PTR_ERR(timer.pclk); + + timer.gclk = of_clk_get_by_name(node, "gclk"); + if (IS_ERR(timer.gclk)) + return PTR_ERR(timer.gclk); + + timer.base = of_iomap(node, 0); + if (!timer.base) + return -ENXIO; + + if (clkevt) { + irq = irq_of_parse_and_map(node, 0); + if (!irq) { + ret = -ENODEV; + goto io_unmap; + } + } + + /* Initialize mode (prescaler + SGCK bit). To be used at runtime. */ + ret = mchp_pit64b_init_mode(&timer, freq); + if (ret) + goto irq_unmap; + + ret = clk_prepare_enable(timer.pclk); + if (ret) + goto irq_unmap; + + if (timer.mode & MCHP_PIT64B_MR_SGCLK) { + ret = clk_prepare_enable(timer.gclk); + if (ret) + goto pclk_unprepare; + + clk_rate = clk_get_rate(timer.gclk); + } else { + clk_rate = clk_get_rate(timer.pclk); + } + clk_rate = clk_rate / (MCHP_PIT64B_MODE_TO_PRES(timer.mode) + 1); + + if (clkevt) + ret = mchp_pit64b_init_clkevt(&timer, clk_rate, irq); + else + ret = mchp_pit64b_init_clksrc(&timer, clk_rate); + + if (ret) + goto gclk_unprepare; + + return 0; + +gclk_unprepare: + if (timer.mode & MCHP_PIT64B_MR_SGCLK) + clk_disable_unprepare(timer.gclk); +pclk_unprepare: + clk_disable_unprepare(timer.pclk); +irq_unmap: + irq_dispose_mapping(irq); +io_unmap: + iounmap(timer.base); + + return ret; +} + +static int __init mchp_pit64b_dt_init(struct device_node *node) +{ + static int inits; + + switch (inits++) { + case 0: + /* 1st request, register clockevent. */ + return mchp_pit64b_dt_init_timer(node, true); + case 1: + /* 2nd request, register clocksource. */ + return mchp_pit64b_dt_init_timer(node, false); + } + + /* The rest, don't care. */ + return -EINVAL; +} + +TIMER_OF_DECLARE(mchp_pit64b, "microchip,sam9x60-pit64b", mchp_pit64b_dt_init); -- 2.7.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply related [flat|nested] 9+ messages in thread
* [tip: timers/core] clocksource/drivers/timer-microchip-pit64b: Add Microchip PIT64B support 2019-12-13 11:19 ` Claudiu Beznea (?) @ 2020-01-16 21:31 ` tip-bot2 for Claudiu Beznea -1 siblings, 0 replies; 9+ messages in thread From: tip-bot2 for Claudiu Beznea @ 2020-01-16 21:31 UTC (permalink / raw) To: linux-tip-commits; +Cc: Claudiu Beznea, Daniel Lezcano, x86, LKML The following commit has been merged into the timers/core branch of tip: Commit-ID: 625022a5f160619ae180d54097ddd65bb3795913 Gitweb: https://git.kernel.org/tip/625022a5f160619ae180d54097ddd65bb3795913 Author: Claudiu Beznea <claudiu.beznea@microchip.com> AuthorDate: Fri, 13 Dec 2019 13:19:21 +02:00 Committer: Daniel Lezcano <daniel.lezcano@linaro.org> CommitterDate: Thu, 16 Jan 2020 19:06:57 +01:00 clocksource/drivers/timer-microchip-pit64b: Add Microchip PIT64B support Add driver for Microchip PIT64B timer. Timer could be used in continuous mode or oneshot mode. The hardware has 2x32 bit registers for period emulating a 64 bit timer. The LSB_PR and MSB_PR registers are used to set the period value (compare value). TLSB and TMSB keeps the current value of the counter. After a compare the TLSB and TMSB register resets. The driver uses PIT64B timer for clocksource or clockevent. First requested timer would be registered as clockevent, second one would be registered as clocksource. Individual PIT64B hardware resources were used for clocksource and clockevent to be able to support high resolution timers with this hardware implementation. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/1576235962-30123-3-git-send-email-claudiu.beznea@microchip.com --- Documentation/devicetree/bindings/arm/atmel-sysregs.txt | 6 +- drivers/clocksource/Kconfig | 10 +- drivers/clocksource/Makefile | 1 +- drivers/clocksource/timer-microchip-pit64b.c | 449 +++++++- 4 files changed, 466 insertions(+) create mode 100644 drivers/clocksource/timer-microchip-pit64b.c diff --git a/Documentation/devicetree/bindings/arm/atmel-sysregs.txt b/Documentation/devicetree/bindings/arm/atmel-sysregs.txt index 9fbde40..e003a55 100644 --- a/Documentation/devicetree/bindings/arm/atmel-sysregs.txt +++ b/Documentation/devicetree/bindings/arm/atmel-sysregs.txt @@ -10,6 +10,12 @@ PIT Timer required properties: - interrupts: Should contain interrupt for the PIT which is the IRQ line shared across all System Controller members. +PIT64B Timer required properties: +- compatible: Should be "microchip,sam9x60-pit64b" +- reg: Should contain registers location and length +- interrupts: Should contain interrupt for PIT64B timer +- clocks: Should contain the available clock sources for PIT64B timer. + System Timer (ST) required properties: - compatible: Should be "atmel,at91rm9200-st", "syscon", "simple-mfd" - reg: Should contain registers location and length diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 94192fb..cc909e4 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -697,4 +697,14 @@ config INGENIC_TIMER help Support for the timer/counter unit of the Ingenic JZ SoCs. +config MICROCHIP_PIT64B + bool "Microchip PIT64B support" + depends on OF || COMPILE_TEST + select CLKSRC_MMIO + help + This option enables Microchip PIT64B timer for Atmel + based system. It supports the oneshot, the periodic + modes and high resolution. It is used as a clocksource + and a clockevent. + endmenu diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 4dfe422..713686f 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -88,3 +88,4 @@ obj-$(CONFIG_RISCV_TIMER) += timer-riscv.o obj-$(CONFIG_CSKY_MP_TIMER) += timer-mp-csky.o obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o obj-$(CONFIG_HYPERV_TIMER) += hyperv_timer.o +obj-$(CONFIG_MICROCHIP_PIT64B) += timer-microchip-pit64b.o diff --git a/drivers/clocksource/timer-microchip-pit64b.c b/drivers/clocksource/timer-microchip-pit64b.c new file mode 100644 index 0000000..27a389a --- /dev/null +++ b/drivers/clocksource/timer-microchip-pit64b.c @@ -0,0 +1,449 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 64-bit Periodic Interval Timer driver + * + * Copyright (C) 2019 Microchip Technology Inc. and its subsidiaries + * + * Author: Claudiu Beznea <claudiu.beznea@microchip.com> + */ + +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/sched_clock.h> +#include <linux/slab.h> + +#define MCHP_PIT64B_CR 0x00 /* Control Register */ +#define MCHP_PIT64B_CR_START BIT(0) +#define MCHP_PIT64B_CR_SWRST BIT(8) + +#define MCHP_PIT64B_MR 0x04 /* Mode Register */ +#define MCHP_PIT64B_MR_CONT BIT(0) +#define MCHP_PIT64B_MR_ONE_SHOT (0) +#define MCHP_PIT64B_MR_SGCLK BIT(3) +#define MCHP_PIT64B_MR_PRES GENMASK(11, 8) + +#define MCHP_PIT64B_LSB_PR 0x08 /* LSB Period Register */ + +#define MCHP_PIT64B_MSB_PR 0x0C /* MSB Period Register */ + +#define MCHP_PIT64B_IER 0x10 /* Interrupt Enable Register */ +#define MCHP_PIT64B_IER_PERIOD BIT(0) + +#define MCHP_PIT64B_ISR 0x1C /* Interrupt Status Register */ + +#define MCHP_PIT64B_TLSBR 0x20 /* Timer LSB Register */ + +#define MCHP_PIT64B_TMSBR 0x24 /* Timer MSB Register */ + +#define MCHP_PIT64B_PRES_MAX 0x10 +#define MCHP_PIT64B_LSBMASK GENMASK_ULL(31, 0) +#define MCHP_PIT64B_PRES_TO_MODE(p) (MCHP_PIT64B_MR_PRES & ((p) << 8)) +#define MCHP_PIT64B_MODE_TO_PRES(m) ((MCHP_PIT64B_MR_PRES & (m)) >> 8) +#define MCHP_PIT64B_DEF_CS_FREQ 5000000UL /* 5 MHz */ +#define MCHP_PIT64B_DEF_CE_FREQ 32768 /* 32 KHz */ + +#define MCHP_PIT64B_NAME "pit64b" + +/** + * struct mchp_pit64b_timer - PIT64B timer data structure + * @base: base address of PIT64B hardware block + * @pclk: PIT64B's peripheral clock + * @gclk: PIT64B's generic clock + * @mode: precomputed value for mode register + */ +struct mchp_pit64b_timer { + void __iomem *base; + struct clk *pclk; + struct clk *gclk; + u32 mode; +}; + +/** + * mchp_pit64b_clkevt - PIT64B clockevent data structure + * @timer: PIT64B timer + * @clkevt: clockevent + */ +struct mchp_pit64b_clkevt { + struct mchp_pit64b_timer timer; + struct clock_event_device clkevt; +}; + +#define to_mchp_pit64b_timer(x) \ + ((struct mchp_pit64b_timer *)container_of(x,\ + struct mchp_pit64b_clkevt, clkevt)) + +/* Base address for clocksource timer. */ +static void __iomem *mchp_pit64b_cs_base; +/* Default cycles for clockevent timer. */ +static u64 mchp_pit64b_ce_cycles; + +static inline u64 mchp_pit64b_cnt_read(void __iomem *base) +{ + unsigned long flags; + u32 low, high; + + raw_local_irq_save(flags); + + /* + * When using a 64 bit period TLSB must be read first, followed by the + * read of TMSB. This sequence generates an atomic read of the 64 bit + * timer value whatever the lapse of time between the accesses. + */ + low = readl_relaxed(base + MCHP_PIT64B_TLSBR); + high = readl_relaxed(base + MCHP_PIT64B_TMSBR); + + raw_local_irq_restore(flags); + + return (((u64)high << 32) | low); +} + +static inline void mchp_pit64b_reset(struct mchp_pit64b_timer *timer, + u64 cycles, u32 mode, u32 irqs) +{ + u32 low, high; + + low = cycles & MCHP_PIT64B_LSBMASK; + high = cycles >> 32; + + writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR); + writel_relaxed(mode | timer->mode, timer->base + MCHP_PIT64B_MR); + writel_relaxed(high, timer->base + MCHP_PIT64B_MSB_PR); + writel_relaxed(low, timer->base + MCHP_PIT64B_LSB_PR); + writel_relaxed(irqs, timer->base + MCHP_PIT64B_IER); + writel_relaxed(MCHP_PIT64B_CR_START, timer->base + MCHP_PIT64B_CR); +} + +static u64 mchp_pit64b_clksrc_read(struct clocksource *cs) +{ + return mchp_pit64b_cnt_read(mchp_pit64b_cs_base); +} + +static u64 mchp_pit64b_sched_read_clk(void) +{ + return mchp_pit64b_cnt_read(mchp_pit64b_cs_base); +} + +static int mchp_pit64b_clkevt_shutdown(struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR); + + return 0; +} + +static int mchp_pit64b_clkevt_set_periodic(struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + mchp_pit64b_reset(timer, mchp_pit64b_ce_cycles, MCHP_PIT64B_MR_CONT, + MCHP_PIT64B_IER_PERIOD); + + return 0; +} + +static int mchp_pit64b_clkevt_set_next_event(unsigned long evt, + struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + mchp_pit64b_reset(timer, evt, MCHP_PIT64B_MR_ONE_SHOT, + MCHP_PIT64B_IER_PERIOD); + + return 0; +} + +static void mchp_pit64b_clkevt_suspend(struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR); + if (timer->mode & MCHP_PIT64B_MR_SGCLK) + clk_disable_unprepare(timer->gclk); + clk_disable_unprepare(timer->pclk); +} + +static void mchp_pit64b_clkevt_resume(struct clock_event_device *cedev) +{ + struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev); + + clk_prepare_enable(timer->pclk); + if (timer->mode & MCHP_PIT64B_MR_SGCLK) + clk_prepare_enable(timer->gclk); +} + +static irqreturn_t mchp_pit64b_interrupt(int irq, void *dev_id) +{ + struct mchp_pit64b_clkevt *irq_data = dev_id; + + /* Need to clear the interrupt. */ + readl_relaxed(irq_data->timer.base + MCHP_PIT64B_ISR); + + irq_data->clkevt.event_handler(&irq_data->clkevt); + + return IRQ_HANDLED; +} + +static void __init mchp_pit64b_pres_compute(u32 *pres, u32 clk_rate, + u32 max_rate) +{ + u32 tmp; + + for (*pres = 0; *pres < MCHP_PIT64B_PRES_MAX; (*pres)++) { + tmp = clk_rate / (*pres + 1); + if (tmp <= max_rate) + break; + } + + /* Use the bigest prescaler if we didn't match one. */ + if (*pres == MCHP_PIT64B_PRES_MAX) + *pres = MCHP_PIT64B_PRES_MAX - 1; +} + +/** + * mchp_pit64b_init_mode - prepare PIT64B mode register value to be used at + * runtime; this includes prescaler and SGCLK bit + * + * PIT64B timer may be fed by gclk or pclk. When gclk is used its rate has to + * be at least 3 times lower that pclk's rate. pclk rate is fixed, gclk rate + * could be changed via clock APIs. The chosen clock (pclk or gclk) could be + * divided by the internal PIT64B's divider. + * + * This function, first tries to use GCLK by requesting the desired rate from + * PMC and then using the internal PIT64B prescaler, if any, to reach the + * requested rate. If PCLK/GCLK < 3 (condition requested by PIT64B hardware) + * then the function falls back on using PCLK as clock source for PIT64B timer + * choosing the highest prescaler in case it doesn't locate one to match the + * requested frequency. + * + * Below is presented the PIT64B block in relation with PMC: + * + * PIT64B + * PMC +------------------------------------+ + * +----+ | +-----+ | + * | |-->gclk -->|-->| | +---------+ +-----+ | + * | | | | MUX |--->| Divider |->|timer| | + * | |-->pclk -->|-->| | +---------+ +-----+ | + * +----+ | +-----+ | + * | ^ | + * | sel | + * +------------------------------------+ + * + * Where: + * - gclk rate <= pclk rate/3 + * - gclk rate could be requested from PMC + * - pclk rate is fixed (cannot be requested from PMC) + */ +static int __init mchp_pit64b_init_mode(struct mchp_pit64b_timer *timer, + unsigned long max_rate) +{ + unsigned long pclk_rate, diff = 0, best_diff = ULONG_MAX; + long gclk_round = 0; + u32 pres, best_pres = 0; + + pclk_rate = clk_get_rate(timer->pclk); + if (!pclk_rate) + return -EINVAL; + + /* Try using GCLK. */ + gclk_round = clk_round_rate(timer->gclk, max_rate); + if (gclk_round < 0) + goto pclk; + + if (pclk_rate / gclk_round < 3) + goto pclk; + + mchp_pit64b_pres_compute(&pres, gclk_round, max_rate); + best_diff = abs(gclk_round / (pres + 1) - max_rate); + best_pres = pres; + + if (!best_diff) { + timer->mode |= MCHP_PIT64B_MR_SGCLK; + goto done; + } + +pclk: + /* Check if requested rate could be obtained using PCLK. */ + mchp_pit64b_pres_compute(&pres, pclk_rate, max_rate); + diff = abs(pclk_rate / (pres + 1) - max_rate); + + if (best_diff > diff) { + /* Use PCLK. */ + best_pres = pres; + } else { + /* Use GCLK. */ + timer->mode |= MCHP_PIT64B_MR_SGCLK; + clk_set_rate(timer->gclk, gclk_round); + } + +done: + timer->mode |= MCHP_PIT64B_PRES_TO_MODE(best_pres); + + pr_info("PIT64B: using clk=%s with prescaler %u, freq=%lu [Hz]\n", + timer->mode & MCHP_PIT64B_MR_SGCLK ? "gclk" : "pclk", best_pres, + timer->mode & MCHP_PIT64B_MR_SGCLK ? + gclk_round / (best_pres + 1) : pclk_rate / (best_pres + 1)); + + return 0; +} + +static int __init mchp_pit64b_init_clksrc(struct mchp_pit64b_timer *timer, + u32 clk_rate) +{ + int ret; + + mchp_pit64b_reset(timer, ULLONG_MAX, MCHP_PIT64B_MR_CONT, 0); + + mchp_pit64b_cs_base = timer->base; + + ret = clocksource_mmio_init(timer->base, MCHP_PIT64B_NAME, clk_rate, + 210, 64, mchp_pit64b_clksrc_read); + if (ret) { + pr_debug("clksrc: Failed to register PIT64B clocksource!\n"); + + /* Stop timer. */ + writel_relaxed(MCHP_PIT64B_CR_SWRST, + timer->base + MCHP_PIT64B_CR); + + return ret; + } + + sched_clock_register(mchp_pit64b_sched_read_clk, 64, clk_rate); + + return 0; +} + +static int __init mchp_pit64b_init_clkevt(struct mchp_pit64b_timer *timer, + u32 clk_rate, u32 irq) +{ + struct mchp_pit64b_clkevt *ce; + int ret; + + ce = kzalloc(sizeof(*ce), GFP_KERNEL); + if (!ce) + return -ENOMEM; + + mchp_pit64b_ce_cycles = DIV_ROUND_CLOSEST(clk_rate, HZ); + + ce->timer.base = timer->base; + ce->timer.pclk = timer->pclk; + ce->timer.gclk = timer->gclk; + ce->timer.mode = timer->mode; + ce->clkevt.name = MCHP_PIT64B_NAME; + ce->clkevt.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC; + ce->clkevt.rating = 150; + ce->clkevt.set_state_shutdown = mchp_pit64b_clkevt_shutdown; + ce->clkevt.set_state_periodic = mchp_pit64b_clkevt_set_periodic; + ce->clkevt.set_next_event = mchp_pit64b_clkevt_set_next_event; + ce->clkevt.suspend = mchp_pit64b_clkevt_suspend; + ce->clkevt.resume = mchp_pit64b_clkevt_resume; + ce->clkevt.cpumask = cpumask_of(0); + ce->clkevt.irq = irq; + + ret = request_irq(irq, mchp_pit64b_interrupt, IRQF_TIMER, + "pit64b_tick", ce); + if (ret) { + pr_debug("clkevt: Failed to setup PIT64B IRQ\n"); + kfree(ce); + return ret; + } + + clockevents_config_and_register(&ce->clkevt, clk_rate, 1, ULONG_MAX); + + return 0; +} + +static int __init mchp_pit64b_dt_init_timer(struct device_node *node, + bool clkevt) +{ + u32 freq = clkevt ? MCHP_PIT64B_DEF_CE_FREQ : MCHP_PIT64B_DEF_CS_FREQ; + struct mchp_pit64b_timer timer = { 0 }; + unsigned long clk_rate; + u32 irq = 0; + int ret; + + /* Parse DT node. */ + timer.pclk = of_clk_get_by_name(node, "pclk"); + if (IS_ERR(timer.pclk)) + return PTR_ERR(timer.pclk); + + timer.gclk = of_clk_get_by_name(node, "gclk"); + if (IS_ERR(timer.gclk)) + return PTR_ERR(timer.gclk); + + timer.base = of_iomap(node, 0); + if (!timer.base) + return -ENXIO; + + if (clkevt) { + irq = irq_of_parse_and_map(node, 0); + if (!irq) { + ret = -ENODEV; + goto io_unmap; + } + } + + /* Initialize mode (prescaler + SGCK bit). To be used at runtime. */ + ret = mchp_pit64b_init_mode(&timer, freq); + if (ret) + goto irq_unmap; + + ret = clk_prepare_enable(timer.pclk); + if (ret) + goto irq_unmap; + + if (timer.mode & MCHP_PIT64B_MR_SGCLK) { + ret = clk_prepare_enable(timer.gclk); + if (ret) + goto pclk_unprepare; + + clk_rate = clk_get_rate(timer.gclk); + } else { + clk_rate = clk_get_rate(timer.pclk); + } + clk_rate = clk_rate / (MCHP_PIT64B_MODE_TO_PRES(timer.mode) + 1); + + if (clkevt) + ret = mchp_pit64b_init_clkevt(&timer, clk_rate, irq); + else + ret = mchp_pit64b_init_clksrc(&timer, clk_rate); + + if (ret) + goto gclk_unprepare; + + return 0; + +gclk_unprepare: + if (timer.mode & MCHP_PIT64B_MR_SGCLK) + clk_disable_unprepare(timer.gclk); +pclk_unprepare: + clk_disable_unprepare(timer.pclk); +irq_unmap: + irq_dispose_mapping(irq); +io_unmap: + iounmap(timer.base); + + return ret; +} + +static int __init mchp_pit64b_dt_init(struct device_node *node) +{ + static int inits; + + switch (inits++) { + case 0: + /* 1st request, register clockevent. */ + return mchp_pit64b_dt_init_timer(node, true); + case 1: + /* 2nd request, register clocksource. */ + return mchp_pit64b_dt_init_timer(node, false); + } + + /* The rest, don't care. */ + return -EINVAL; +} + +TIMER_OF_DECLARE(mchp_pit64b, "microchip,sam9x60-pit64b", mchp_pit64b_dt_init); ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH v4 0/2] add Microchip PIT64B timer 2019-12-13 11:19 ` Claudiu Beznea @ 2019-12-16 9:16 ` Daniel Lezcano -1 siblings, 0 replies; 9+ messages in thread From: Daniel Lezcano @ 2019-12-16 9:16 UTC (permalink / raw) To: Claudiu Beznea, robh+dt, mark.rutland, nicolas.ferre, alexandre.belloni, ludovic.desroches, tglx Cc: devicetree, linux-arm-kernel, linux-kernel On 13/12/2019 12:19, Claudiu Beznea wrote: > Hi, > > This series adds driver for Microchip PIT64B timer. > Timer could be used in continuous or oneshot mode. It has 2x32 bit registers > to emulate a 64 bit timer. The timer's period could be configured via LSB_PR > and MSB_PR registers. The current timer's value could be checked via TLSB and > TMSB registers. When (TMSB << 32) | TLSB value reach the (MSB_PR << 32) | LSB_PR > interrupt is raised. If in contiuous mode the TLSB and TMSB resets and restart > counting. > > This drivers uses PIT64B capabilities for clocksource and clockevent. > The first requested PIT64B timer is used for clockevent. The second one is used > for clocksource. Individual PIT64B hardware resources were used for clocksource > and clockevent to be able to support high resolution timers with this PIT64B > implementation. I've applied the patches. Thanks -- Daniel -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v4 0/2] add Microchip PIT64B timer @ 2019-12-16 9:16 ` Daniel Lezcano 0 siblings, 0 replies; 9+ messages in thread From: Daniel Lezcano @ 2019-12-16 9:16 UTC (permalink / raw) To: Claudiu Beznea, robh+dt, mark.rutland, nicolas.ferre, alexandre.belloni, ludovic.desroches, tglx Cc: devicetree, linux-kernel, linux-arm-kernel On 13/12/2019 12:19, Claudiu Beznea wrote: > Hi, > > This series adds driver for Microchip PIT64B timer. > Timer could be used in continuous or oneshot mode. It has 2x32 bit registers > to emulate a 64 bit timer. The timer's period could be configured via LSB_PR > and MSB_PR registers. The current timer's value could be checked via TLSB and > TMSB registers. When (TMSB << 32) | TLSB value reach the (MSB_PR << 32) | LSB_PR > interrupt is raised. If in contiuous mode the TLSB and TMSB resets and restart > counting. > > This drivers uses PIT64B capabilities for clocksource and clockevent. > The first requested PIT64B timer is used for clockevent. The second one is used > for clocksource. Individual PIT64B hardware resources were used for clocksource > and clockevent to be able to support high resolution timers with this PIT64B > implementation. I've applied the patches. Thanks -- Daniel -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2020-01-16 21:31 UTC | newest] Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-12-13 11:19 [PATCH v4 0/2] add Microchip PIT64B timer Claudiu Beznea 2019-12-13 11:19 ` Claudiu Beznea 2019-12-13 11:19 ` [PATCH v4 1/2] dt-bindings: arm: atmel: add bindings for PIT64B Claudiu Beznea 2019-12-13 11:19 ` Claudiu Beznea 2019-12-13 11:19 ` [PATCH v4 2/2] clocksource/drivers/timer-microchip-pit64b: add Microchip PIT64B support Claudiu Beznea 2019-12-13 11:19 ` Claudiu Beznea 2020-01-16 21:31 ` [tip: timers/core] clocksource/drivers/timer-microchip-pit64b: Add " tip-bot2 for Claudiu Beznea 2019-12-16 9:16 ` [PATCH v4 0/2] add Microchip PIT64B timer Daniel Lezcano 2019-12-16 9:16 ` Daniel Lezcano
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.