diff options
Diffstat (limited to 'arch/arm/mach-omap2/timer-gp.c')
| -rw-r--r-- | arch/arm/mach-omap2/timer-gp.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/timer-gp.c b/arch/arm/mach-omap2/timer-gp.c new file mode 100644 index 000000000000..9ec11443200f --- /dev/null +++ b/arch/arm/mach-omap2/timer-gp.c @@ -0,0 +1,126 @@ +/* + * linux/arch/arm/mach-omap2/timer-gp.c + * + * OMAP2 GP timer support. + * + * Copyright (C) 2005 Nokia Corporation + * Author: Paul Mundt <paul.mundt@nokia.com> + * Juha Yrjölä <juha.yrjola@nokia.com> + * + * Some parts based off of TI's 24xx code: + * + * Copyright (C) 2004 Texas Instruments, Inc. + * + * Roughly modelled after the OMAP1 MPU timer code. + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ +#include <linux/init.h> +#include <linux/time.h> +#include <linux/interrupt.h> +#include <linux/err.h> +#include <asm/mach/time.h> +#include <asm/delay.h> +#include <asm/io.h> +#include <asm/hardware/clock.h> + +#define OMAP2_GP_TIMER1_BASE 0x48028000 +#define OMAP2_GP_TIMER2_BASE 0x4802a000 +#define OMAP2_GP_TIMER3_BASE 0x48078000 +#define OMAP2_GP_TIMER4_BASE 0x4807a000 + +#define GP_TIMER_TIDR 0x00 +#define GP_TIMER_TISR 0x18 +#define GP_TIMER_TIER 0x1c +#define GP_TIMER_TCLR 0x24 +#define GP_TIMER_TCRR 0x28 +#define GP_TIMER_TLDR 0x2c +#define GP_TIMER_TSICR 0x40 + +#define OS_TIMER_NR 1 /* GP timer 2 */ + +static unsigned long timer_base[] = { + IO_ADDRESS(OMAP2_GP_TIMER1_BASE), + IO_ADDRESS(OMAP2_GP_TIMER2_BASE), + IO_ADDRESS(OMAP2_GP_TIMER3_BASE), + IO_ADDRESS(OMAP2_GP_TIMER4_BASE), +}; + +static inline unsigned int timer_read_reg(int nr, unsigned int reg) +{ + return __raw_readl(timer_base[nr] + reg); +} + +static inline void timer_write_reg(int nr, unsigned int reg, unsigned int val) +{ + __raw_writel(val, timer_base[nr] + reg); +} + +/* Note that we always enable the clock prescale divider bit */ +static inline void omap2_gp_timer_start(int nr, unsigned long load_val) +{ + unsigned int tmp; + + tmp = 0xffffffff - load_val; + + timer_write_reg(nr, GP_TIMER_TLDR, tmp); + timer_write_reg(nr, GP_TIMER_TCRR, tmp); + timer_write_reg(nr, GP_TIMER_TIER, 1 << 1); + timer_write_reg(nr, GP_TIMER_TCLR, (1 << 5) | (1 << 1) | 1); +} + +static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id, + struct pt_regs *regs) +{ + write_seqlock(&xtime_lock); + + timer_write_reg(OS_TIMER_NR, GP_TIMER_TISR, 1 << 1); + timer_tick(regs); + + write_sequnlock(&xtime_lock); + + return IRQ_HANDLED; +} + +static struct irqaction omap2_gp_timer_irq = { + .name = "gp timer", + .flags = SA_INTERRUPT, + .handler = omap2_gp_timer_interrupt, +}; + +static void __init omap2_gp_timer_init(void) +{ + struct clk * sys_ck; + u32 tick_period = 120000; + u32 l; + + /* Reset clock and prescale value */ + timer_write_reg(OS_TIMER_NR, GP_TIMER_TCLR, 0); + + sys_ck = clk_get(NULL, "sys_ck"); + if (IS_ERR(sys_ck)) + printk(KERN_ERR "Could not get sys_ck\n"); + else { + clk_use(sys_ck); + tick_period = clk_get_rate(sys_ck) / 100; + clk_put(sys_ck); + } + + tick_period /= 2; /* Minimum prescale divider is 2 */ + tick_period -= 1; + + l = timer_read_reg(OS_TIMER_NR, GP_TIMER_TIDR); + printk(KERN_INFO "OMAP2 GP timer (HW version %d.%d)\n", + (l >> 4) & 0x0f, l & 0x0f); + + setup_irq(38, &omap2_gp_timer_irq); + + omap2_gp_timer_start(OS_TIMER_NR, tick_period); +} + +struct sys_timer omap_timer = { + .init = omap2_gp_timer_init, +}; + |