Switch the mx35 timer driver to the 32-kHz clock source to avoid calling
mxc_get_clock() again and again, and to be consistent with the timer drivers of
other i.MX SoCs.
Signed-off-by: Benoît Thébaudeau <benoit.thebaud...@advansee.com>
Cc: Stefano Babic <sba...@denx.de>
---
Changes for v2:
- Fix multiline comment style.
- Use default SoC input clock frequency definitions instead of duplicating
frequency definitions in all board files.
.../arch/arm/cpu/arm1136/mx35/timer.c | 44 ++++++++++++--------
1 file changed, 27 insertions(+), 17 deletions(-)
diff --git u-boot-imx-88e73dd.orig/arch/arm/cpu/arm1136/mx35/timer.c
u-boot-imx-88e73dd/arch/arm/cpu/arm1136/mx35/timer.c
index 6000042..9680b7f 100644
--- u-boot-imx-88e73dd.orig/arch/arm/cpu/arm1136/mx35/timer.c
+++ u-boot-imx-88e73dd/arch/arm/cpu/arm1136/mx35/timer.c
@@ -27,6 +27,7 @@
#include <asm/io.h>
#include <div64.h>
#include <asm/arch/imx-regs.h>
+#include <asm/arch/crm_regs.h>
#include <asm/arch/clock.h>
DECLARE_GLOBAL_DATA_PTR;
@@ -37,43 +38,52 @@ DECLARE_GLOBAL_DATA_PTR;
/* General purpose timers bitfields */
#define GPTCR_SWR (1<<15) /* Software reset */
#define GPTCR_FRR (1<<9) /* Freerun / restart */
-#define GPTCR_CLKSOURCE_32 (0x100<<6) /* Clock source */
-#define GPTCR_CLKSOURCE_IPG (0x001<<6) /* Clock source */
+#define GPTCR_CLKSOURCE_32 (4<<6) /* Clock source */
#define GPTCR_TEN (1) /* Timer enable */
-#define TIMER_FREQ_HZ mxc_get_clock(MXC_IPG_CLK)
-
+/*
+ * "time" is measured in 1 / CONFIG_SYS_HZ seconds,
+ * "tick" is internal timer period
+ */
+/* ~0.4% error - measured with stop-watch on 100s boot-delay */
static inline unsigned long long tick_to_time(unsigned long long tick)
{
tick *= CONFIG_SYS_HZ;
- do_div(tick, TIMER_FREQ_HZ);
+ do_div(tick, MXC_CLK32);
return tick;
}
-static inline unsigned long long us_to_tick(unsigned long long usec)
+static inline unsigned long long us_to_tick(unsigned long long us)
{
- usec *= TIMER_FREQ_HZ;
- do_div(usec, 1000000);
+ us = us * MXC_CLK32 + 999999;
+ do_div(us, 1000000);
- return usec;
+ return us;
}
+/*
+ * nothing really to do with interrupts, just starts up a counter.
+ * The 32KHz 32-bit timer overruns in 134217 seconds
+ */
int timer_init(void)
{
int i;
struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR;
+ struct ccm_regs *ccm = (struct ccm_regs *)CCM_BASE_ADDR;
/* setup GP Timer 1 */
writel(GPTCR_SWR, &gpt->ctrl);
- for (i = 0; i < 100; i++)
- writel(0, &gpt->ctrl); /* We have no udelay by now */
- writel(0, &gpt->pre);
- /* Freerun Mode, PERCLK1 input */
- writel(readl(&gpt->ctrl) |
- GPTCR_CLKSOURCE_IPG | GPTCR_TEN,
- &gpt->ctrl);
+ writel(readl(&ccm->cgr1) | 3 << MXC_CCM_CGR1_GPT_OFFSET, &ccm->cgr1);
+
+ for (i = 0; i < 100; i++)
+ writel(0, &gpt->ctrl); /* We have no udelay by now */
+ writel(0, &gpt->pre); /* prescaler = 1 */
+ /* Freerun Mode, 32KHz input */
+ writel(readl(&gpt->ctrl) | GPTCR_CLKSOURCE_32 | GPTCR_FRR,
+ &gpt->ctrl);
+ writel(readl(&gpt->ctrl) | GPTCR_TEN, &gpt->ctrl);
return 0;
}
@@ -132,5 +142,5 @@ void __udelay(unsigned long usec)
*/
ulong get_tbclk(void)
{
- return TIMER_FREQ_HZ;
+ return MXC_CLK32;
}
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