[U-Boot] [PATCH v3] OMAP3: Fix timer handling to 1ms and CONFIG_SYS_HZ to 1000

Dirk Behme
2009-04-21T15:29:05Z

From: Manikandan Pillai <mani.pillai@ti.com>
Signed-off-by: Dirk Behme <dirk.behme@googlemail.com>
Signed-off-by: Manikandan Pillai <mani.pillai@ti.com>
---
Changes in v3 which replaces previous version [3]:

* Fix udelay(), too
* Fix and use TIMER_LOAD_VAL macro
* Rebase against mainline 7ee38c044ca5041d3378d6507580ea4ec344af96
'fix DaVinci NS16550_REG_SIZE regression'

Changes from Dirk's patch which is replaced by this [2]:

* Fix conflicts after commit 81472d893fa565c9d300928a40e504a689bde131

Changes from Mani's original patch which is replaced by this [1]:

* Don't remove overflow handling in get_timer_masked()
* Update omap3_zoom1.h, too.
* Clean up timer related comments and macros in config files
* Don't touch reset_timer_masked()
* Switch divider clock divider from 256 to 8 to be able to get 1000Hz
* Remove unused udelay_masked()
* Minor clean up of get_tbclk()

[1] http://lists.denx.de/pipermail/u-boot/2009-March/049012.html
[2] http://lists.denx.de/pipermail/u-boot/2009-March/049146.html
[3] http://lists.denx.de/pipermail/u-boot/2009-April/050170.html
---
cpu/arm_cortexa8/omap3/interrupts.c | 85 +++++++++++-------------------------
include/configs/omap3_beagle.h | 9 ++-
include/configs/omap3_evm.h | 9 ++-
include/configs/omap3_overo.h | 12 ++---
include/configs/omap3_pandora.h | 11 ++--
include/configs/omap3_zoom1.h | 11 ++--
6 files changed, 55 insertions(+), 82 deletions(-)

Index: u-boot-main/cpu/arm_cortexa8/omap3/interrupts.c
===================================================================
--- u-boot-main.orig/cpu/arm_cortexa8/omap3/interrupts.c
+++ u-boot-main/cpu/arm_cortexa8/omap3/interrupts.c
@@ -36,8 +36,6 @@
#include <asm/io.h>
#include <asm/proc-armv/ptrace.h>

-#define TIMER_LOAD_VAL 0
-
#ifdef CONFIG_USE_IRQ
/* enable IRQ interrupts */
void enable_interrupts(void)
@@ -169,7 +167,17 @@ static ulong timestamp;
static ulong lastinc;
static gptimer_t *timer_base = (gptimer_t *)CONFIG_SYS_TIMERBASE;

-/* nothing really to do with interrupts, just starts up a counter. */
+/*
+ * Nothing really to do with interrupts, just starts up a counter.
+ * We run the counter with 13MHz, divided by 8, resulting in timer
+ * frequency of 1.625MHz. With 32bit counter register, counter
+ * overflows in ~44min
+ */
+
+/* 13MHz / 8 = 1.625MHz */
+#define TIMER_CLOCK (V_SCLK / (2 << CONFIG_SYS_PTV))
+#define TIMER_LOAD_VAL 0xffffffff
+
int interrupt_init(void)
{
/* start the counter ticking up, reload value on overflow */
@@ -201,81 +209,44 @@ void set_timer(ulong t)
timestamp = t;
}

-/* delay x useconds AND perserve advance timstamp value */
+/* delay x useconds */
void udelay(unsigned long usec)
{
- ulong tmo, tmp;
+ long tmo = usec * (TIMER_CLOCK / 1000) / 1000;
+ unsigned long now, last = readl(&timer_base->tcrr);

- /* if "big" number, spread normalization to seconds */
- if (usec >= 1000) {
- /* if "big" number, spread normalization to seconds */
- tmo = usec / 1000;
- /* find number of "ticks" to wait to achieve target */
- tmo *= CONFIG_SYS_HZ;
- tmo /= 1000; /* finish normalize. */
- } else {/* else small number, don't kill it prior to HZ multiply */
- tmo = usec * CONFIG_SYS_HZ;
- tmo /= (1000 * 1000);
+ while (tmo > 0) {
+ now = readl(&timer_base->tcrr);
+ if (last > now) /* count up timer overflow */
+ tmo -= TIMER_LOAD_VAL - last + now;
+ else
+ tmo -= now - last;
+ last = now;
}
-
- tmp = get_timer(0); /* get current timestamp */
- /* if setting this forward will roll time stamp */
- if ((tmo + tmp + 1) < tmp)
- /* reset "advancing" timestamp to 0, set lastinc value */
- reset_timer_masked();
- else
- tmo += tmp; /* else, set advancing stamp wake up time */
- while (get_timer_masked() < tmo) /* loop till event */
- /*NOP*/;
}

void reset_timer_masked(void)
{
/* reset time, capture current incrementer value time */
- lastinc = readl(&timer_base->tcrr);
+ lastinc = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ);
timestamp = 0; /* start "advancing" time stamp from 0 */
}

ulong get_timer_masked(void)
{
- ulong now = readl(&timer_base->tcrr); /* current tick value */
+ /* current tick value */
+ ulong now = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ);

if (now >= lastinc) /* normal mode (non roll) */
/* move stamp fordward with absoulte diff ticks */
timestamp += (now - lastinc);
else /* we have rollover of incrementer */
- timestamp += (0xFFFFFFFF - lastinc) + now;
+ timestamp += ((TIMER_LOAD_VAL / (TIMER_CLOCK / CONFIG_SYS_HZ))
+ - lastinc) + now;
lastinc = now;
return timestamp;
}

-/* waits specified delay value and resets timestamp */
-void udelay_masked(unsigned long usec)
-{
- ulong tmo;
- ulong endtime;
- signed long diff;
-
- /* if "big" number, spread normalization to seconds */
- if (usec >= 1000) {
- /* start to normalize for usec to ticks per sec */
- tmo = usec / 1000;
- /* find number of "ticks" to wait to achieve target */
- tmo *= CONFIG_SYS_HZ;
- tmo /= 1000; /* finish normalize. */
- } else { /* else small number, */
- /* don't kill it prior to HZ multiply */
- tmo = usec * CONFIG_SYS_HZ;
- tmo /= (1000 * 1000);
- }
- endtime = get_timer_masked() + tmo;
-
- do {
- ulong now = get_timer_masked();
- diff = endtime - now;
- } while (diff >= 0);
-}
-
/*
* This function is derived from PowerPC code (read timebase as long long).
* On ARM it just returns the timer value.
@@ -291,7 +262,5 @@ unsigned long long get_ticks(void)
*/
ulong get_tbclk(void)
{
- ulong tbclk;
- tbclk = CONFIG_SYS_HZ;
- return tbclk;
+ return CONFIG_SYS_HZ;
}
Index: u-boot-main/include/configs/omap3_beagle.h
===================================================================
--- u-boot-main.orig/include/configs/omap3_beagle.h
+++ u-boot-main/include/configs/omap3_beagle.h
@@ -223,12 +223,13 @@
/* load address */

/*
- * 2430 has 12 GP timers, they can be driven by the SysClk (12/13/19.2) or by
- * 32KHz clk, or from external sig. This rate is divided by a local divisor.
+ * OMAP3 has 12 GP timers, they can be driven by the system clock
+ * (12/13/16.8/19.2/38.4MHz) or by 32KHz clock. We use 13MHz (V_SCLK).
+ * This rate is divided by a local divisor.
*/
#define CONFIG_SYS_TIMERBASE (OMAP34XX_GPT2)
-#define CONFIG_SYS_PTV 7 /* 2^(PTV+1) */
-#define CONFIG_SYS_HZ ((V_SCLK) / (2 << CONFIG_SYS_PTV))
+#define CONFIG_SYS_PTV 2 /* Divisor: 2^(PTV+1) => 8 */
+#define CONFIG_SYS_HZ 1000

/*-----------------------------------------------------------------------
* Stack sizes
Index: u-boot-main/include/configs/omap3_evm.h
===================================================================
--- u-boot-main.orig/include/configs/omap3_evm.h
+++ u-boot-main/include/configs/omap3_evm.h
@@ -216,12 +216,13 @@
/* address */

/*
- * 2430 has 12 GP timers, they can be driven by the SysClk (12/13/19.2) or by
- * 32KHz clk, or from external sig. This rate is divided by a local divisor.
+ * OMAP3 has 12 GP timers, they can be driven by the system clock
+ * (12/13/16.8/19.2/38.4MHz) or by 32KHz clock. We use 13MHz (V_SCLK).
+ * This rate is divided by a local divisor.
*/
#define CONFIG_SYS_TIMERBASE OMAP34XX_GPT2
-#define CONFIG_SYS_PTV 7 /* 2^(PTV+1) */
-#define CONFIG_SYS_HZ ((V_SCLK) / (2 << CONFIG_SYS_PTV))
+#define CONFIG_SYS_PTV 2 /* Divisor: 2^(PTV+1) => 8 */
+#define CONFIG_SYS_HZ 1000

/*-----------------------------------------------------------------------
* Stack sizes
Index: u-boot-main/include/configs/omap3_overo.h
===================================================================
--- u-boot-main.orig/include/configs/omap3_overo.h
+++ u-boot-main/include/configs/omap3_overo.h
@@ -208,14 +208,14 @@

#define CONFIG_SYS_LOAD_ADDR (OMAP34XX_SDRC_CS0) /* default load */
/* address */
-
/*
- * 2430 has 12 GP timers, they can be driven by the SysClk (12/13/19.2) or by
- * 32KHz clk, or from external sig. This rate is divided by a local divisor.
+ * OMAP3 has 12 GP timers, they can be driven by the system clock
+ * (12/13/16.8/19.2/38.4MHz) or by 32KHz clock. We use 13MHz (V_SCLK).
+ * This rate is divided by a local divisor.
*/
-#define CONFIG_SYS_TIMERBASE (OMAP34XX_GPT2)
-#define CONFIG_SYS_PTV 7 /* 2^(PTV+1) */
-#define CONFIG_SYS_HZ ((V_SCLK) / (2 << CONFIG_SYS_PTV))
+#define CONFIG_SYS_TIMERBASE OMAP34XX_GPT2
+#define CONFIG_SYS_PTV 2 /* Divisor: 2^(PTV+1) => 8 */
+#define CONFIG_SYS_HZ 1000

/*-----------------------------------------------------------------------
* Stack sizes
Index: u-boot-main/include/configs/omap3_pandora.h
===================================================================
--- u-boot-main.orig/include/configs/omap3_pandora.h
+++ u-boot-main/include/configs/omap3_pandora.h
@@ -212,12 +212,13 @@
/* address */

/*
- * 2430 has 12 GP timers, they can be driven by the SysClk (12/13/19.2) or by
- * 32KHz clk, or from external sig. This rate is divided by a local divisor.
+ * OMAP3 has 12 GP timers, they can be driven by the system clock
+ * (12/13/16.8/19.2/38.4MHz) or by 32KHz clock. We use 13MHz (V_SCLK).
+ * This rate is divided by a local divisor.
*/
-#define CONFIG_SYS_TIMERBASE (OMAP34XX_GPT2)
-#define CONFIG_SYS_PTV 7 /* 2^(PTV+1) */
-#define CONFIG_SYS_HZ ((V_SCLK) / (2 << CONFIG_SYS_PTV))
+#define CONFIG_SYS_TIMERBASE OMAP34XX_GPT2
+#define CONFIG_SYS_PTV 2 /* Divisor: 2^(PTV+1) => 8 */
+#define CONFIG_SYS_HZ 1000

/*-----------------------------------------------------------------------
* Stack sizes
Index: u-boot-main/include/configs/omap3_zoom1.h
===================================================================
--- u-boot-main.orig/include/configs/omap3_zoom1.h
+++ u-boot-main/include/configs/omap3_zoom1.h
@@ -220,12 +220,13 @@
/* load address */

/*
- * 2430 has 12 GP timers, they can be driven by the SysClk (12/13/19.2) or by
- * 32KHz clk, or from external sig. This rate is divided by a local divisor.
+ * OMAP3 has 12 GP timers, they can be driven by the system clock
+ * (12/13/16.8/19.2/38.4MHz) or by 32KHz clock. We use 13MHz (V_SCLK).
+ * This rate is divided by a local divisor.
*/
-#define CONFIG_SYS_TIMERBASE (OMAP34XX_GPT2)
-#define CONFIG_SYS_PTV 7 /* 2^(PTV+1) */
-#define CONFIG_SYS_HZ ((V_SCLK) / (2 << CONFIG_SYS_PTV))
+#define CONFIG_SYS_TIMERBASE OMAP34XX_GPT2
+#define CONFIG_SYS_PTV 2 /* Divisor: 2^(PTV+1) => 8 */
+#define CONFIG_SYS_HZ 1000

/*-----------------------------------------------------------------------
* Stack sizes