diff options
Diffstat (limited to 'arch/arm/cpu/arm926ejs/mxs/timer.c')
| -rw-r--r-- | arch/arm/cpu/arm926ejs/mxs/timer.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/arch/arm/cpu/arm926ejs/mxs/timer.c b/arch/arm/cpu/arm926ejs/mxs/timer.c new file mode 100644 index 0000000..2039106 --- /dev/null +++ b/arch/arm/cpu/arm926ejs/mxs/timer.c @@ -0,0 +1,175 @@ +/* + * Freescale i.MX28 timer driver + * + * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com> + * on behalf of DENX Software Engineering GmbH + * + * Based on code from LTIB: + * (C) Copyright 2009-2010 Freescale Semiconductor, Inc. + * + * See file CREDITS for list of people who contributed to this + * project. + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> +#include <asm/io.h> +#include <asm/arch/imx-regs.h> +#include <asm/arch/sys_proto.h> + +/* Maximum fixed count */ +#if defined(CONFIG_MX23) +#define TIMER_LOAD_VAL 0xffff +#elif defined(CONFIG_MX28) +#define TIMER_LOAD_VAL 0xffffffff +#endif + +DECLARE_GLOBAL_DATA_PTR; + +#define timestamp (gd->arch.tbl) +#define lastdec (gd->arch.lastinc) + +/* + * This driver uses 1kHz clock source. + */ +#define MXS_INCREMENTER_HZ 1000 + +static inline unsigned long tick_to_time(unsigned long tick) +{ + return tick / (MXS_INCREMENTER_HZ / CONFIG_SYS_HZ); +} + +static inline unsigned long time_to_tick(unsigned long time) +{ + return time * (MXS_INCREMENTER_HZ / CONFIG_SYS_HZ); +} + +/* Calculate how many ticks happen in "us" microseconds */ +static inline unsigned long us_to_tick(unsigned long us) +{ + return (us * MXS_INCREMENTER_HZ) / 1000000; +} + +int timer_init(void) +{ + struct mxs_timrot_regs *timrot_regs = + (struct mxs_timrot_regs *)MXS_TIMROT_BASE; + + /* Reset Timers and Rotary Encoder module */ + mxs_reset_block(&timrot_regs->hw_timrot_rotctrl_reg); + + /* Set fixed_count to 0 */ +#if defined(CONFIG_MX23) + writel(0, &timrot_regs->hw_timrot_timcount0); +#elif defined(CONFIG_MX28) + writel(0, &timrot_regs->hw_timrot_fixed_count0); +#endif + + /* Set UPDATE bit and 1Khz frequency */ + writel(TIMROT_TIMCTRLn_UPDATE | TIMROT_TIMCTRLn_RELOAD | + TIMROT_TIMCTRLn_SELECT_1KHZ_XTAL, + &timrot_regs->hw_timrot_timctrl0); + + /* Set fixed_count to maximal value */ +#if defined(CONFIG_MX23) + writel(TIMER_LOAD_VAL - 1, &timrot_regs->hw_timrot_timcount0); +#elif defined(CONFIG_MX28) + writel(TIMER_LOAD_VAL, &timrot_regs->hw_timrot_fixed_count0); +#endif + + return 0; +} + +unsigned long long get_ticks(void) +{ + struct mxs_timrot_regs *timrot_regs = + (struct mxs_timrot_regs *)MXS_TIMROT_BASE; + uint32_t now; + + /* Current tick value */ +#if defined(CONFIG_MX23) + /* Upper bits are the valid ones. */ + now = readl(&timrot_regs->hw_timrot_timcount0) >> + TIMROT_RUNNING_COUNTn_RUNNING_COUNT_OFFSET; +#elif defined(CONFIG_MX28) + now = readl(&timrot_regs->hw_timrot_running_count0); +#endif + + if (lastdec >= now) { + /* + * normal mode (non roll) + * move stamp forward with absolut diff ticks + */ + timestamp += (lastdec - now); + } else { + /* we have rollover of decrementer */ + timestamp += (TIMER_LOAD_VAL - now) + lastdec; + + } + lastdec = now; + + return timestamp; +} + +ulong get_timer_masked(void) +{ + return tick_to_time(get_ticks()); +} + +ulong get_timer(ulong base) +{ + return get_timer_masked() - base; +} + +/* We use the HW_DIGCTL_MICROSECONDS register for sub-millisecond timer. */ +#define MXS_HW_DIGCTL_MICROSECONDS 0x8001c0c0 + +void __udelay(unsigned long usec) +{ + uint32_t old, new, incr; + uint32_t counter = 0; + + old = readl(MXS_HW_DIGCTL_MICROSECONDS); + + while (counter < usec) { + new = readl(MXS_HW_DIGCTL_MICROSECONDS); + + /* Check if the timer wrapped. */ + if (new < old) { + incr = 0xffffffff - old; + incr += new; + } else { + incr = new - old; + } + + /* + * Check if we are close to the maximum time and the counter + * would wrap if incremented. If that's the case, break out + * from the loop as the requested delay time passed. + */ + if (counter + incr < counter) + break; + + counter += incr; + old = new; + } +} + +ulong get_tbclk(void) +{ + return MXS_INCREMENTER_HZ; +} |
