summaryrefslogtreecommitdiff
path: root/arch/arm/imx-common/timer.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/imx-common/timer.c')
-rw-r--r--arch/arm/imx-common/timer.c149
1 files changed, 149 insertions, 0 deletions
diff --git a/arch/arm/imx-common/timer.c b/arch/arm/imx-common/timer.c
new file mode 100644
index 0000000..e2725e1
--- /dev/null
+++ b/arch/arm/imx-common/timer.c
@@ -0,0 +1,149 @@
+/*
+ * (C) Copyright 2007
+ * Sascha Hauer, Pengutronix
+ *
+ * (C) Copyright 2009 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 <div64.h>
+#include <asm/arch/imx-regs.h>
+
+/* General purpose timers registers */
+struct mxc_gpt {
+ unsigned int control;
+ unsigned int prescaler;
+ unsigned int status;
+ unsigned int nouse[6];
+ unsigned int counter;
+};
+
+static struct mxc_gpt *cur_gpt = (struct mxc_gpt *)GPT1_BASE_ADDR;
+
+/* General purpose timers bitfields */
+#define GPTCR_SWR (1 << 15) /* Software reset */
+#define GPTCR_FRR (1 << 9) /* Freerun / restart */
+#define GPTCR_CLKSOURCE_32 (4 << 6) /* Clock source */
+#define GPTCR_TEN 1 /* Timer enable */
+#define CLK_32KHZ 32768 /* 32Khz input */
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define timestamp (gd->tbl)
+#define lastinc (gd->lastinc)
+
+static inline unsigned long long tick_to_time(unsigned long long tick)
+{
+ tick *= CONFIG_SYS_HZ;
+ do_div(tick, CLK_32KHZ);
+
+ return tick;
+}
+
+static inline unsigned long long us_to_tick(unsigned long long usec)
+{
+ usec = usec * CLK_32KHZ + 999999;
+ do_div(usec, 1000000);
+
+ return usec;
+}
+
+int timer_init(void)
+{
+ int i;
+ ulong val;
+
+ /* setup GP Timer 1 */
+ __raw_writel(GPTCR_SWR, &cur_gpt->control);
+
+ /* We have no udelay by now */
+ for (i = 0; i < 100; i++)
+ __raw_writel(0, &cur_gpt->control);
+
+ __raw_writel(0, &cur_gpt->prescaler); /* 32Khz */
+
+ /* Freerun Mode, PERCLK1 input */
+ i = __raw_readl(&cur_gpt->control);
+ __raw_writel(i | GPTCR_CLKSOURCE_32 | GPTCR_TEN, &cur_gpt->control);
+
+ val = __raw_readl(&cur_gpt->counter);
+ lastinc = val / (CLK_32KHZ / CONFIG_SYS_HZ);
+ timestamp = 0;
+
+ return 0;
+}
+
+unsigned long long get_ticks(void)
+{
+ ulong now = __raw_readl(&cur_gpt->counter); /* current tick value */
+
+ if (now >= lastinc) {
+ /*
+ * normal mode (non roll)
+ * move stamp forward with absolut diff ticks
+ */
+ timestamp += (now - lastinc);
+ } else {
+ /* we have rollover of incrementer */
+ timestamp += (0xFFFFFFFF - lastinc) + now;
+ }
+ lastinc = now;
+ return timestamp;
+}
+
+ulong get_timer_masked(void)
+{
+ /*
+ * get_ticks() returns a long long (64 bit), it wraps in
+ * 2^64 / CONFIG_MX25_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~
+ * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in
+ * 5 * 10^6 days - long enough.
+ */
+ return tick_to_time(get_ticks());
+}
+
+ulong get_timer(ulong base)
+{
+ return get_timer_masked() - base;
+}
+
+/* delay x useconds AND preserve advance timstamp value */
+void __udelay(unsigned long usec)
+{
+ unsigned long long tmp;
+ ulong tmo;
+
+ tmo = us_to_tick(usec);
+ tmp = get_ticks() + tmo; /* get current timestamp */
+
+ while (get_ticks() < tmp) /* loop till event */
+ /*NOP*/;
+}
+
+/*
+ * This function is derived from PowerPC code (timebase clock frequency).
+ * On ARM it returns the number of timer ticks per second.
+ */
+ulong get_tbclk(void)
+{
+ return CLK_32KHZ;
+}