linux-kernel - [PATCH 2/2] clocksource/drivers/imx-tpm: add different counter width support

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Message-ID: <1522050461-19043-2-git-send-email-Anson.Huang@nxp.com>
Date:   Mon, 26 Mar 2018 15:47:41 +0800
From:   Anson Huang <Anson.Huang@....com>
To:     <daniel.lezcano@...aro.org>, <tglx@...utronix.de>,
        <robh+dt@...nel.org>, <mark.rutland@....com>,
        <aisheng.dong@....com>
CC:     <Linux-imx@....com>, <linux-kernel@...r.kernel.org>,
        <devicetree@...r.kernel.org>
Subject: [PATCH 2/2] clocksource/drivers/imx-tpm: add different counter width support

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@....com>
---
 drivers/clocksource/timer-imx-tpm.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/clocksource/timer-imx-tpm.c b/drivers/clocksource/timer-imx-tpm.c
index 7403e49..5063b77 100644
--- a/drivers/clocksource/timer-imx-tpm.c
+++ b/drivers/clocksource/timer-imx-tpm.c
@@ -17,6 +17,9 @@
 #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
@@ -33,6 +36,7 @@
 #define TPM_C0SC_CHF_MASK		(0x1 << 7)
 #define TPM_C0V				0x24
 
+static int counter_width;
 static void __iomem *timer_base;
 static struct clock_event_device clockevent_tpm;
 
@@ -66,7 +70,7 @@ static struct delay_timer tpm_delay_timer;
 
 static inline unsigned long tpm_read_counter(void)
 {
-	return readl(timer_base + TPM_CNT);
+	return readl(timer_base + TPM_CNT) & GENMASK(counter_width - 1, 0);
 }
 
 static unsigned long tpm_read_current_timer(void)
@@ -85,10 +89,11 @@ 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, 200, counter_width,
+				     clocksource_mmio_readl_up);
 }
 
 static int tpm_set_next_event(unsigned long delta,
@@ -153,8 +158,8 @@ static int __init tpm_clockevent_init(unsigned long rate, int irq)
 
 	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 +204,8 @@ 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;
 	/*
 	 * Initialize tpm module to a known state
 	 * 1) Counter disabled
@@ -220,7 +227,7 @@ static int __init tpm_timer_init(struct device_node *np)
 		     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