diff options
Diffstat (limited to 'lib_i386')
| -rw-r--r-- | lib_i386/Makefile | 2 | ||||
| -rw-r--r-- | lib_i386/pcat_timer.c | 102 | ||||
| -rw-r--r-- | lib_i386/timer.c | 107 |
3 files changed, 211 insertions, 0 deletions
diff --git a/lib_i386/Makefile b/lib_i386/Makefile index fb4184b..ec6f236 100644 --- a/lib_i386/Makefile +++ b/lib_i386/Makefile @@ -39,7 +39,9 @@ COBJS-y += video_bios.o COBJS-y += video.o COBJS-y += zimage.o COBJS-y += interrupts.o +COBJS-y += timer.o COBJS-$(CONFIG_SYS_PCAT_INTERRUPTS) += pcat_interrupts.o +COBJS-$(CONFIG_SYS_GENERIC_TIMER) += pcat_timer.o SRCS := $(SOBJS-y:.o=.S) $(COBJS-y:.o=.c) OBJS := $(addprefix $(obj),$(SOBJS-y) $(COBJS-y)) diff --git a/lib_i386/pcat_timer.c b/lib_i386/pcat_timer.c new file mode 100644 index 0000000..e282f64 --- /dev/null +++ b/lib_i386/pcat_timer.c @@ -0,0 +1,102 @@ +/* + * (C) Copyright 2002 + * Daniel Engström, Omicron Ceti AB, daniel@omicron.se. + * + * 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/i8254.h> +#include <asm/ibmpc.h> + +#define TIMER0_VALUE 0x04aa /* 1kHz 1.9318MHz / 1000 */ +#define TIMER2_VALUE 0x0a8e /* 440Hz */ + +int timer_init(void) +{ + /* initialize timer 0 and 2 + * + * Timer 0 is used to increment system_tick 1000 times/sec + * Timer 1 was used for DRAM refresh in early PC's + * Timer 2 is used to drive the speaker + * (to stasrt a beep: write 3 to port 0x61, + * to stop it again: write 0) + */ + outb (PIT_CMD_CTR0 | PIT_CMD_BOTH | PIT_CMD_MODE2, + PIT_BASE + PIT_COMMAND); + outb (TIMER0_VALUE & 0xff, PIT_BASE + PIT_T0); + outb (TIMER0_VALUE >> 8, PIT_BASE + PIT_T0); + + outb (PIT_CMD_CTR2 | PIT_CMD_BOTH | PIT_CMD_MODE3, + PIT_BASE + PIT_COMMAND); + outb (TIMER2_VALUE & 0xff, PIT_BASE + PIT_T2); + outb (TIMER2_VALUE >> 8, PIT_BASE + PIT_T2); + + irq_install_handler (0, timer_isr, NULL); + unmask_irq (0); + + return 0; +} + +static u16 read_pit(void) +{ + u8 low; + + outb (PIT_CMD_LATCH, PIT_BASE + PIT_COMMAND); + low = inb (PIT_BASE + PIT_T0); + + return ((inb (PIT_BASE + PIT_T0) << 8) | low); +} + +/* this is not very exact */ +void udelay (unsigned long usec) +{ + int counter; + int wraps; + + if (timer_init_done) + { + counter = read_pit (); + wraps = usec / 1000; + usec = usec % 1000; + + usec *= 1194; + usec /= 1000; + usec += counter; + + while (usec > 1194) { + usec -= 1194; + wraps++; + } + + while (1) { + int new_count = read_pit (); + + if (((new_count < usec) && !wraps) || wraps < 0) + break; + + if (new_count > counter) + wraps--; + + counter = new_count; + } + } + +} diff --git a/lib_i386/timer.c b/lib_i386/timer.c new file mode 100644 index 0000000..5cb1f54 --- /dev/null +++ b/lib_i386/timer.c @@ -0,0 +1,107 @@ +/* + * (C) Copyright 2002 + * Daniel Engström, Omicron Ceti AB, daniel@omicron.se. + * + * 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 <malloc.h> +#include <asm/io.h> +#include <asm/i8254.h> +#include <asm/ibmpc.h> + +struct timer_isr_function { + struct timer_isr_function *next; + timer_fnc_t *isr_func; +}; + +static struct timer_isr_function *first_timer_isr = NULL; +static volatile unsigned long system_ticks = 0; + +/* + * register_timer_isr() allows multiple architecture and board specific + * functions to be called every millisecond. Keep the execution time of + * each function as low as possible + */ +int register_timer_isr (timer_fnc_t *isr_func) +{ + struct timer_isr_function *new_func; + struct timer_isr_function *temp; + int flag; + + new_func = malloc(sizeof(struct timer_isr_function)); + + if (new_func == NULL) + return 1; + + new_func->isr_func = isr_func; + new_func->next = NULL; + + /* + * Don't allow timer interrupts while the + * linked list is being modified + */ + flag = disable_interrupts (); + + if (first_timer_isr == NULL) { + first_timer_isr = new_func; + } else { + temp = first_timer_isr; + while (temp->next != NULL) + temp = temp->next; + temp->next = new_func; + } + + if (flag) + enable_interrupts (); + + return 0; +} + +/* + * timer_isr() MUST be the registered interrupt handler for + */ +void timer_isr(void *unused) +{ + struct timer_isr_function *temp = first_timer_isr; + + system_ticks++; + + /* Execute each registered function */ + while (temp != NULL) { + temp->isr_func (); + temp = temp->next; + } +} + +void reset_timer (void) +{ + system_ticks = 0; +} + +ulong get_timer (ulong base) +{ + return (system_ticks - base); +} + +void set_timer (ulong t) +{ + system_ticks = t; +} |