From d6c62b739b35744de673d5fdb573ffdabc7d9a8d Mon Sep 17 00:00:00 2001 From: Jules Maselbas Date: Thu, 29 Nov 2018 13:45:56 +0100 Subject: clocksource: Add dw_apb_timer driver Adapt linux kernel dw_apb_timer driver to barebox. Signed-off-by: Jules Maselbas Signed-off-by: Sascha Hauer --- drivers/clocksource/Kconfig | 5 ++ drivers/clocksource/Makefile | 1 + drivers/clocksource/dw_apb_timer.c | 148 +++++++++++++++++++++++++++++++++++++ 3 files changed, 154 insertions(+) create mode 100644 drivers/clocksource/dw_apb_timer.c (limited to 'drivers/clocksource') diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 02659d86ac..337a7a2e13 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -83,4 +83,9 @@ config CLOCKSOURCE_IMX_GPT def_bool y depends on ARCH_HAS_IMX_GPT +config CLOCKSOURCE_DW_APB_TIMER + bool "DW APB timer driver" + help + Enables the support for the dw_apb timer. + endmenu diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index ce4d74137a..ab78f0700d 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -14,3 +14,4 @@ obj-$(CONFIG_CLOCKSOURCE_ATMEL_PIT) += timer-atmel-pit.o obj-$(CONFIG_CLOCKSOURCE_ARMV8_TIMER) += armv8-timer.o obj-$(CONFIG_CLOCKSOURCE_ARM_GLOBAL_TIMER) += arm_global_timer.o obj-$(CONFIG_CLOCKSOURCE_IMX_GPT) += timer-imx-gpt.o +obj-$(CONFIG_CLOCKSOURCE_DW_APB_TIMER) += dw_apb_timer.o diff --git a/drivers/clocksource/dw_apb_timer.c b/drivers/clocksource/dw_apb_timer.c new file mode 100644 index 0000000000..82ad6bccbc --- /dev/null +++ b/drivers/clocksource/dw_apb_timer.c @@ -0,0 +1,148 @@ +/* + * (C) Copyright 2009 Intel Corporation + * Author: Jacob Pan (jacob.jun.pan@intel.com) + * + * Shared with ARM platforms, Jamie Iles, Picochip 2011 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Support for the Synopsys DesignWare APB Timers. + * + * + * Taken from linux-4.9 kernel and adapted to barebox. + */ +#include +#include +#include + +#include +#include + +#define APBT_MIN_PERIOD 4 +#define APBT_MIN_DELTA_USEC 200 + +#define APBTMR_N_LOAD_COUNT 0x00 +#define APBTMR_N_CURRENT_VALUE 0x04 +#define APBTMR_N_CONTROL 0x08 +#define APBTMR_N_EOI 0x0c +#define APBTMR_N_INT_STATUS 0x10 + +#define APBTMRS_INT_STATUS 0xa0 +#define APBTMRS_EOI 0xa4 +#define APBTMRS_RAW_INT_STATUS 0xa8 +#define APBTMRS_COMP_VERSION 0xac + +#define APBTMR_CONTROL_ENABLE (1 << 0) +/* 1: periodic, 0:free running. */ +#define APBTMR_CONTROL_MODE_PERIODIC (1 << 1) +#define APBTMR_CONTROL_INT (1 << 2) + +#define APBTMRS_REG_SIZE 0x14 + +struct dw_apb_timer { + void __iomem *base; + unsigned long freq; + int irq; +}; + +static struct dw_apb_timer timer; + +static inline u32 apbt_readl(struct dw_apb_timer *timer, unsigned long offs) +{ + return readl(timer->base + offs); +} + +static inline void apbt_writel(struct dw_apb_timer *timer, u32 val, + unsigned long offs) +{ + writel(val, timer->base + offs); +} + +/** + * dw_apb_clocksource_start() - start the clocksource counting. + * + * @clksrc: The clocksource to start. + * + * This is used to start the clocksource before registration and can be used + * to enable calibration of timers. + */ +static int dw_apb_clocksource_start(struct clocksource *clksrc) +{ + /* + * start count down from 0xffff_ffff. this is done by toggling the + * enable bit then load initial load count to ~0. + */ + uint32_t ctrl = apbt_readl(&timer, APBTMR_N_CONTROL); + + ctrl &= ~APBTMR_CONTROL_ENABLE; + apbt_writel(&timer, ctrl, APBTMR_N_CONTROL); + apbt_writel(&timer, ~0, APBTMR_N_LOAD_COUNT); + + /* enable, mask interrupt */ + ctrl &= ~APBTMR_CONTROL_MODE_PERIODIC; + ctrl |= (APBTMR_CONTROL_ENABLE | APBTMR_CONTROL_INT); + apbt_writel(&timer, ctrl, APBTMR_N_CONTROL); + + return 0; +} + +static uint64_t dw_apb_clocksource_read(void) +{ + return (uint64_t) ~apbt_readl(&timer, APBTMR_N_CURRENT_VALUE); +} + +static struct clocksource dw_apb_clksrc = { + .init = dw_apb_clocksource_start, + .read = dw_apb_clocksource_read, + .mask = CLOCKSOURCE_MASK(32), + .shift = 0, +}; + +static int dw_apb_timer_probe(struct device_d *dev) +{ + struct device_node *np = dev->device_node; + struct resource *iores; + struct clk *clk; + uint32_t clk_freq; + + /* use only one timer */ + if (timer.base) + return -EBUSY; + + iores = dev_request_mem_resource(dev, 0); + if (IS_ERR(iores)) { + dev_err(dev, "could not get memory region\n"); + return PTR_ERR(iores); + } + + timer.base = IOMEM(iores->start); + + /* Get clock frequency */ + clk = of_clk_get(np, 0); + if (IS_ERR(clk)) { + pr_err("Failed to get CPU clock: %ld\n", PTR_ERR(clk)); + return PTR_ERR(clk); + } + + clk_freq = clk_get_rate(clk); + clk_put(clk); + + dw_apb_clksrc.mult = clocksource_hz2mult(clk_freq, dw_apb_clksrc.shift); + + return init_clock(&dw_apb_clksrc); +} + +static struct of_device_id dw_apb_timer_dt_ids[] = { + { .compatible = "snps,dw-apb-timer", }, + { } +}; + +static struct driver_d dw_apb_timer_driver = { + .name = "dw-apb-timer", + .probe = dw_apb_timer_probe, + .of_compatible = DRV_OF_COMPAT(dw_apb_timer_dt_ids), +}; + +device_platform_driver(dw_apb_timer_driver); -- cgit v1.2.3