Different TPM modules have different width counters which
is 16-bit or 32-bit, the counter width can be read from
TPM_PARAM register bit[23:16], this patch adds dynamic
check for counter width to support both 16-bit and 32-bit
TPM modules.
Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
---
changes since V1:
use largest prescaler for 16-bit counter;
use lower rating for 16-bit counter than 32-bit;
remove the computing in counter read function.
drivers/clocksource/timer-imx-tpm.c | 33 +++++++++++++++++++++++++--------
1 file changed, 25 insertions(+), 8 deletions(-)
diff --git a/drivers/clocksource/timer-imx-tpm.c b/drivers/clocksource/timer-imx-tpm.c
index 7403e49..05d97a6 100644
--- a/drivers/clocksource/timer-imx-tpm.c
+++ b/drivers/clocksource/timer-imx-tpm.c
@@ -17,9 +17,13 @@
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
+#define TPM_PARAM 0x4
+#define TPM_PARAM_WIDTH_SHIFT 16
+#define TPM_PARAM_WIDTH_MASK (0xff << 16)
#define TPM_SC 0x10
#define TPM_SC_CMOD_INC_PER_CNT (0x1 << 3)
#define TPM_SC_CMOD_DIV_DEFAULT 0x3
+#define TPM_SC_CMOD_DIV_MAX 0x7
#define TPM_SC_TOF_MASK (0x1 << 7)
#define TPM_CNT 0x14
#define TPM_MOD 0x18
@@ -33,6 +37,8 @@
#define TPM_C0SC_CHF_MASK (0x1 << 7)
#define TPM_C0V 0x24
+static int counter_width;
+static int rating;
static void __iomem *timer_base;
static struct clock_event_device clockevent_tpm;
@@ -85,10 +91,11 @@ static int __init tpm_clocksource_init(unsigned long rate)
tpm_delay_timer.freq = rate;
register_current_timer_delay(&tpm_delay_timer);
- sched_clock_register(tpm_read_sched_clock, 32, rate);
+ sched_clock_register(tpm_read_sched_clock, counter_width, rate);
return clocksource_mmio_init(timer_base + TPM_CNT, "imx-tpm",
- rate, 200, 32, clocksource_mmio_readl_up);
+ rate, rating, counter_width,
+ clocksource_mmio_readl_up);
}
static int tpm_set_next_event(unsigned long delta,
@@ -141,7 +148,6 @@ static struct clock_event_device clockevent_tpm = {
.set_state_oneshot = tpm_set_state_oneshot,
.set_next_event = tpm_set_next_event,
.set_state_shutdown = tpm_set_state_shutdown,
- .rating = 200,
};
static int __init tpm_clockevent_init(unsigned long rate, int irq)
@@ -151,10 +157,11 @@ static int __init tpm_clockevent_init(unsigned long rate, int irq)
ret = request_irq(irq, tpm_timer_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
"i.MX7ULP TPM Timer", &clockevent_tpm);
+ clockevent_tpm.rating = rating;
clockevent_tpm.cpumask = cpumask_of(0);
clockevent_tpm.irq = irq;
- clockevents_config_and_register(&clockevent_tpm,
- rate, 300, 0xfffffffe);
+ clockevents_config_and_register(&clockevent_tpm, rate, 300,
+ GENMASK(counter_width - 1, 1));
return ret;
}
@@ -199,6 +206,11 @@ static int __init tpm_timer_init(struct device_node *np)
goto err_per_clk_enable;
}
+ counter_width = (readl(timer_base + TPM_PARAM) & TPM_PARAM_WIDTH_MASK)
+ >> TPM_PARAM_WIDTH_SHIFT;
+ /* use rating 200 for 32-bit counter and 150 for 16-bit counter */
+ rating = counter_width == 0x20 ? 200 : 150;
+
/*
* Initialize tpm module to a known state
* 1) Counter disabled
@@ -215,12 +227,17 @@ static int __init tpm_timer_init(struct device_node *np)
/* CHF is W1C */
writel(TPM_C0SC_CHF_MASK, timer_base + TPM_C0SC);
- /* increase per cnt, div 8 by default */
- writel(TPM_SC_CMOD_INC_PER_CNT | TPM_SC_CMOD_DIV_DEFAULT,
+ /*
+ * increase per cnt,
+ * div 8 for 32-bit counter and div 128 for 16-bit counter
+ */
+ writel(TPM_SC_CMOD_INC_PER_CNT |
+ (counter_width == 0x20 ?
+ TPM_SC_CMOD_DIV_DEFAULT : TPM_SC_CMOD_DIV_MAX),
timer_base + TPM_SC);
/* set MOD register to maximum for free running mode */
- writel(0xffffffff, timer_base + TPM_MOD);
+ writel(GENMASK(counter_width - 1, 0), timer_base + TPM_MOD);
rate = clk_get_rate(per) >> 3;
ret = tpm_clocksource_init(rate);
--
2.7.4
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