[PATCH v2 01/18] clocksource: sp804: Add support for non-32bit width counter

[Neil Armstrong]

Some vendor variants can implement norrower counter width, add
an optional DT property changing the clocksource width and the
clockevent mask, but keeping 32bit as default for legacy interface.

Signed-off-by: Neil Armstrong <narmstrong at baylibre.com>
---
 drivers/clocksource/timer-sp804.c | 38 +++++++++++++++++++++++++++-----------
 include/clocksource/timer-sp804.h | 11 ++++++-----
 2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/drivers/clocksource/timer-sp804.c b/drivers/clocksource/timer-sp804.c
index 5f45b9a..8acf524 100644
--- a/drivers/clocksource/timer-sp804.c
+++ b/drivers/clocksource/timer-sp804.c
@@ -80,7 +80,8 @@ void __init sp804_timer_disable(void __iomem *base)
 void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
 						     const char *name,
 						     struct clk *clk,
-						     int use_sched_clock)
+						     int use_sched_clock,
+						     unsigned width)
 {
 	long rate;
 
@@ -93,6 +94,9 @@ void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
 		}
 	}
 
+	if (!width || width > 32)
+		width = 32;
+
 	rate = sp804_get_clock_rate(clk);
 
 	if (rate < 0)
@@ -106,11 +110,11 @@ void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
 		base + TIMER_CTRL);
 
 	clocksource_mmio_init(base + TIMER_VALUE, name,
-		rate, 200, 32, clocksource_mmio_readl_down);
+		rate, 200, width, clocksource_mmio_readl_down);
 
 	if (use_sched_clock) {
 		sched_clock_base = base;
-		sched_clock_register(sp804_read, 32, rate);
+		sched_clock_register(sp804_read, width, rate);
 	}
 }
 
@@ -186,7 +190,9 @@ static struct irqaction sp804_timer_irq = {
 	.dev_id		= &sp804_clockevent,
 };
 
-void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struct clk *clk, const char *name)
+void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq,
+				     struct clk *clk, const char *name,
+				     unsigned width)
 {
 	struct clock_event_device *evt = &sp804_clockevent;
 	long rate;
@@ -199,6 +205,9 @@ void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struc
 		return;
 	}
 
+	if (!width || width > 32)
+		width = 32;
+
 	rate = sp804_get_clock_rate(clk);
 	if (rate < 0)
 		return;
@@ -212,7 +221,7 @@ void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struc
 	writel(0, base + TIMER_CTRL);
 
 	setup_irq(irq, &sp804_timer_irq);
-	clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
+	clockevents_config_and_register(evt, rate, 0xf, GENMASK(width-1, 0));
 }
 
 static void __init sp804_of_init(struct device_node *np)
@@ -223,6 +232,7 @@ static void __init sp804_of_init(struct device_node *np)
 	u32 irq_num = 0;
 	struct clk *clk1, *clk2;
 	const char *name = of_get_property(np, "compatible", NULL);
+	u32 width = 32;
 
 	base = of_iomap(np, 0);
 	if (WARN_ON(!base))
@@ -254,14 +264,19 @@ static void __init sp804_of_init(struct device_node *np)
 	if (irq <= 0)
 		goto err;
 
+	/* Some vendor variants can have a different counter width */
+	of_property_read_u32(np, "arm,timer-width", &width);
+
 	of_property_read_u32(np, "arm,sp804-has-irq", &irq_num);
 	if (irq_num == 2) {
-		__sp804_clockevents_init(base + TIMER_2_BASE, irq, clk2, name);
-		__sp804_clocksource_and_sched_clock_init(base, name, clk1, 1);
+		__sp804_clockevents_init(base + TIMER_2_BASE, irq,
+					 clk2, name, width);
+		__sp804_clocksource_and_sched_clock_init(base, name,
+							 clk1, 1, width);
 	} else {
-		__sp804_clockevents_init(base, irq, clk1 , name);
+		__sp804_clockevents_init(base, irq, clk1, name, width);
 		__sp804_clocksource_and_sched_clock_init(base + TIMER_2_BASE,
-							 name, clk2, 1);
+							 name, clk2, 1, width);
 	}
 	initialized = true;
 
@@ -293,13 +308,14 @@ static void __init integrator_cp_of_init(struct device_node *np)
 		goto err;
 
 	if (!init_count)
-		__sp804_clocksource_and_sched_clock_init(base, name, clk, 0);
+		__sp804_clocksource_and_sched_clock_init(base, name,
+							 clk, 0, 32);
 	else {
 		irq = irq_of_parse_and_map(np, 0);
 		if (irq <= 0)
 			goto err;
 
-		__sp804_clockevents_init(base, irq, clk, name);
+		__sp804_clockevents_init(base, irq, clk, name, 32);
 	}
 
 	init_count++;
diff --git a/include/clocksource/timer-sp804.h b/include/clocksource/timer-sp804.h
index 1f8a1ca..ad71fcb 100644
--- a/include/clocksource/timer-sp804.h
+++ b/include/clocksource/timer-sp804.h
@@ -4,25 +4,26 @@
 struct clk;
 
 void __sp804_clocksource_and_sched_clock_init(void __iomem *,
-					      const char *, struct clk *, int);
+					      const char *, struct clk *,
+					      int, unsigned);
 void __sp804_clockevents_init(void __iomem *, unsigned int,
-			      struct clk *, const char *);
+			      struct clk *, const char *, unsigned);
 void sp804_timer_disable(void __iomem *);
 
 static inline void sp804_clocksource_init(void __iomem *base, const char *name)
 {
-	__sp804_clocksource_and_sched_clock_init(base, name, NULL, 0);
+	__sp804_clocksource_and_sched_clock_init(base, name, NULL, 0, 32);
 }
 
 static inline void sp804_clocksource_and_sched_clock_init(void __iomem *base,
 							  const char *name)
 {
-	__sp804_clocksource_and_sched_clock_init(base, name, NULL, 1);
+	__sp804_clocksource_and_sched_clock_init(base, name, NULL, 1, 32);
 }
 
 static inline void sp804_clockevents_init(void __iomem *base, unsigned int irq, const char *name)
 {
-	__sp804_clockevents_init(base, irq, NULL, name);
+	__sp804_clockevents_init(base, irq, NULL, name, 32);
 
 }
 #endif
-- 
1.9.1