diff options
Diffstat (limited to 'kernel/drivers/clocksource/asm9260_timer.c')
| -rw-r--r-- | kernel/drivers/clocksource/asm9260_timer.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/kernel/drivers/clocksource/asm9260_timer.c b/kernel/drivers/clocksource/asm9260_timer.c new file mode 100644 index 000000000..2c9c99372 --- /dev/null +++ b/kernel/drivers/clocksource/asm9260_timer.c @@ -0,0 +1,220 @@ +/* + * Copyright (C) 2014 Oleksij Rempel <linux@rempel-privat.de> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/sched.h> +#include <linux/clk.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/bitops.h> + +#define DRIVER_NAME "asm9260-timer" + +/* + * this device provide 4 offsets for each register: + * 0x0 - plain read write mode + * 0x4 - set mode, OR logic. + * 0x8 - clr mode, XOR logic. + * 0xc - togle mode. + */ +#define SET_REG 4 +#define CLR_REG 8 + +#define HW_IR 0x0000 /* RW. Interrupt */ +#define BM_IR_CR0 BIT(4) +#define BM_IR_MR3 BIT(3) +#define BM_IR_MR2 BIT(2) +#define BM_IR_MR1 BIT(1) +#define BM_IR_MR0 BIT(0) + +#define HW_TCR 0x0010 /* RW. Timer controller */ +/* BM_C*_RST + * Timer Counter and the Prescale Counter are synchronously reset on the + * next positive edge of PCLK. The counters remain reset until TCR[1] is + * returned to zero. */ +#define BM_C3_RST BIT(7) +#define BM_C2_RST BIT(6) +#define BM_C1_RST BIT(5) +#define BM_C0_RST BIT(4) +/* BM_C*_EN + * 1 - Timer Counter and Prescale Counter are enabled for counting + * 0 - counters are disabled */ +#define BM_C3_EN BIT(3) +#define BM_C2_EN BIT(2) +#define BM_C1_EN BIT(1) +#define BM_C0_EN BIT(0) + +#define HW_DIR 0x0020 /* RW. Direction? */ +/* 00 - count up + * 01 - count down + * 10 - ?? 2^n/2 */ +#define BM_DIR_COUNT_UP 0 +#define BM_DIR_COUNT_DOWN 1 +#define BM_DIR0_SHIFT 0 +#define BM_DIR1_SHIFT 4 +#define BM_DIR2_SHIFT 8 +#define BM_DIR3_SHIFT 12 +#define BM_DIR_DEFAULT (BM_DIR_COUNT_UP << BM_DIR0_SHIFT | \ + BM_DIR_COUNT_UP << BM_DIR1_SHIFT | \ + BM_DIR_COUNT_UP << BM_DIR2_SHIFT | \ + BM_DIR_COUNT_UP << BM_DIR3_SHIFT) + +#define HW_TC0 0x0030 /* RO. Timer counter 0 */ +/* HW_TC*. Timer counter owerflow (0xffff.ffff to 0x0000.0000) do not generate + * interrupt. This registers can be used to detect overflow */ +#define HW_TC1 0x0040 +#define HW_TC2 0x0050 +#define HW_TC3 0x0060 + +#define HW_PR 0x0070 /* RW. prescaler */ +#define BM_PR_DISABLE 0 +#define HW_PC 0x0080 /* RO. Prescaler counter */ +#define HW_MCR 0x0090 /* RW. Match control */ +/* enable interrupt on match */ +#define BM_MCR_INT_EN(n) (1 << (n * 3 + 0)) +/* enable TC reset on match */ +#define BM_MCR_RES_EN(n) (1 << (n * 3 + 1)) +/* enable stop TC on match */ +#define BM_MCR_STOP_EN(n) (1 << (n * 3 + 2)) + +#define HW_MR0 0x00a0 /* RW. Match reg */ +#define HW_MR1 0x00b0 +#define HW_MR2 0x00C0 +#define HW_MR3 0x00D0 + +#define HW_CTCR 0x0180 /* Counter control */ +#define BM_CTCR0_SHIFT 0 +#define BM_CTCR1_SHIFT 2 +#define BM_CTCR2_SHIFT 4 +#define BM_CTCR3_SHIFT 6 +#define BM_CTCR_TM 0 /* Timer mode. Every rising PCLK edge. */ +#define BM_CTCR_DEFAULT (BM_CTCR_TM << BM_CTCR0_SHIFT | \ + BM_CTCR_TM << BM_CTCR1_SHIFT | \ + BM_CTCR_TM << BM_CTCR2_SHIFT | \ + BM_CTCR_TM << BM_CTCR3_SHIFT) + +static struct asm9260_timer_priv { + void __iomem *base; + unsigned long ticks_per_jiffy; +} priv; + +static int asm9260_timer_set_next_event(unsigned long delta, + struct clock_event_device *evt) +{ + /* configure match count for TC0 */ + writel_relaxed(delta, priv.base + HW_MR0); + /* enable TC0 */ + writel_relaxed(BM_C0_EN, priv.base + HW_TCR + SET_REG); + return 0; +} + +static void asm9260_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + /* stop timer0 */ + writel_relaxed(BM_C0_EN, priv.base + HW_TCR + CLR_REG); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + /* disable reset and stop on match */ + writel_relaxed(BM_MCR_RES_EN(0) | BM_MCR_STOP_EN(0), + priv.base + HW_MCR + CLR_REG); + /* configure match count for TC0 */ + writel_relaxed(priv.ticks_per_jiffy, priv.base + HW_MR0); + /* enable TC0 */ + writel_relaxed(BM_C0_EN, priv.base + HW_TCR + SET_REG); + break; + case CLOCK_EVT_MODE_ONESHOT: + /* enable reset and stop on match */ + writel_relaxed(BM_MCR_RES_EN(0) | BM_MCR_STOP_EN(0), + priv.base + HW_MCR + SET_REG); + break; + default: + break; + } +} + +static struct clock_event_device event_dev = { + .name = DRIVER_NAME, + .rating = 200, + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_next_event = asm9260_timer_set_next_event, + .set_mode = asm9260_timer_set_mode, +}; + +static irqreturn_t asm9260_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + evt->event_handler(evt); + + writel_relaxed(BM_IR_MR0, priv.base + HW_IR); + + return IRQ_HANDLED; +} + +/* + * --------------------------------------------------------------------------- + * Timer initialization + * --------------------------------------------------------------------------- + */ +static void __init asm9260_timer_init(struct device_node *np) +{ + int irq; + struct clk *clk; + int ret; + unsigned long rate; + + priv.base = of_io_request_and_map(np, 0, np->name); + if (!priv.base) + panic("%s: unable to map resource", np->name); + + clk = of_clk_get(np, 0); + + ret = clk_prepare_enable(clk); + if (ret) + panic("Failed to enable clk!\n"); + + irq = irq_of_parse_and_map(np, 0); + ret = request_irq(irq, asm9260_timer_interrupt, IRQF_TIMER, + DRIVER_NAME, &event_dev); + if (ret) + panic("Failed to setup irq!\n"); + + /* set all timers for count-up */ + writel_relaxed(BM_DIR_DEFAULT, priv.base + HW_DIR); + /* disable divider */ + writel_relaxed(BM_PR_DISABLE, priv.base + HW_PR); + /* make sure all timers use every rising PCLK edge. */ + writel_relaxed(BM_CTCR_DEFAULT, priv.base + HW_CTCR); + /* enable interrupt for TC0 and clean setting for all other lines */ + writel_relaxed(BM_MCR_INT_EN(0) , priv.base + HW_MCR); + + rate = clk_get_rate(clk); + clocksource_mmio_init(priv.base + HW_TC1, DRIVER_NAME, rate, + 200, 32, clocksource_mmio_readl_up); + + /* Seems like we can't use counter without match register even if + * actions for MR are disabled. So, set MR to max value. */ + writel_relaxed(0xffffffff, priv.base + HW_MR1); + /* enable TC1 */ + writel_relaxed(BM_C1_EN, priv.base + HW_TCR + SET_REG); + + priv.ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ); + event_dev.cpumask = cpumask_of(0); + clockevents_config_and_register(&event_dev, rate, 0x2c00, 0xfffffffe); +} +CLOCKSOURCE_OF_DECLARE(asm9260_timer, "alphascale,asm9260-timer", + asm9260_timer_init); |