From e0f1fd4c82129eab2c607763f3bdb376eda7dd84 Mon Sep 17 00:00:00 2001 From: Stefan Kristiansson Date: Sat, 26 Nov 2011 19:04:52 +0000 Subject: openrisc: Add library functions Signed-off-by: Stefan Kristiansson --- arch/openrisc/lib/timer.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 104 insertions(+) create mode 100644 arch/openrisc/lib/timer.c (limited to 'arch/openrisc/lib/timer.c') diff --git a/arch/openrisc/lib/timer.c b/arch/openrisc/lib/timer.c new file mode 100644 index 0000000000..4e92a31159 --- /dev/null +++ b/arch/openrisc/lib/timer.c @@ -0,0 +1,104 @@ +/* + * (C) Copyright 2011, Stefan Kristiansson + * (C) Copyright 2011, Julius Baxter + * (C) Copyright 2003 + * Wolfgang Denk, DENX Software Engineering, wd@denx.de. + * + * 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 +#include +#include + +static ulong timestamp; + +/* how many counter cycles in a jiffy */ +#define TIMER_COUNTER_CYCLES (CONFIG_SYS_CLK_FREQ/CONFIG_SYS_OPENRISC_TMR_HZ) +/* how many ms elapses between each timer interrupt */ +#define TIMER_TIMESTAMP_INC (1000/CONFIG_SYS_OPENRISC_TMR_HZ) +/* how many cycles per ms */ +#define TIMER_CYCLES_MS (CONFIG_SYS_CLK_FREQ/1000) +/* how many cycles per us */ +#define TIMER_CYCLES_US (CONFIG_SYS_CLK_FREQ/1000000uL) + +void timer_isr(void) +{ + timestamp += TIMER_TIMESTAMP_INC; + mtspr(SPR_TTMR, SPR_TTMR_IE | SPR_TTMR_RT | + (TIMER_COUNTER_CYCLES & SPR_TTMR_TP)); +} + +int timer_init(void) +{ + /* Install timer exception handler */ + exception_install_handler(EXC_TIMER, timer_isr); + + /* Set up the timer for the first expiration. */ + timestamp = 0; + + mtspr(SPR_TTMR, SPR_TTMR_IE | SPR_TTMR_RT | + (TIMER_COUNTER_CYCLES & SPR_TTMR_TP)); + + /* Enable tick timer exception in supervisor register */ + mtspr(SPR_SR, mfspr(SPR_SR) | SPR_SR_TEE); + + return 0; +} + +void reset_timer(void) +{ + timestamp = 0; + + mtspr(SPR_TTMR, SPR_TTMR_IE | SPR_TTMR_RT | + (TIMER_COUNTER_CYCLES & SPR_TTMR_TP)); +} + +/* + * The timer value in ms is calculated by taking the + * value accumulated by full timer revolutions plus the value + * accumulated in this period + */ +ulong get_timer(ulong base) +{ + return timestamp + mfspr(SPR_TTCR)/TIMER_CYCLES_MS - base; +} + +void set_timer(ulong t) +{ + reset_timer(); + timestamp = t; +} + +void __udelay(ulong usec) +{ + ulong elapsed = 0; + ulong tick; + ulong last_tick; + + last_tick = mfspr(SPR_TTCR); + while ((elapsed / TIMER_CYCLES_US) < usec) { + tick = mfspr(SPR_TTCR); + if (tick >= last_tick) + elapsed += (tick - last_tick); + else + elapsed += TIMER_COUNTER_CYCLES - (last_tick - tick); + last_tick = tick; + } +} -- cgit v1.2.3