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authorGraeme Russ <graeme.russ@gmail.com>2009-02-24 21:14:45 +1100
committerWolfgang Denk <wd@denx.de>2009-03-20 22:39:13 +0100
commit8c63d47651f77d9fb887cad433370b866eb0a193 (patch)
tree3b1462085a3aceec7390c05e7ab8184124967d14 /lib_i386
parent6d7f610b09f813b1239eedcbfe921cfd439aea25 (diff)
Implement SC520 timers
Signed-off-by: Graeme Russ <graeme.russ at gmail.com>
Diffstat (limited to 'lib_i386')
-rw-r--r--lib_i386/Makefile2
-rw-r--r--lib_i386/pcat_timer.c102
-rw-r--r--lib_i386/timer.c107
3 files changed, 211 insertions, 0 deletions
diff --git a/lib_i386/Makefile b/lib_i386/Makefile
index fb4184b3676..ec6f2360522 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 00000000000..e282f649acf
--- /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 00000000000..5cb1f54fb56
--- /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;
+}