ARM: at91: PIT: (Almost) remove the global variables

The timer driver is using some global variables to define some variables it has
to use in most of its functions, like the base address.

Use some container_of calls to have a single dynamic (and local) variable to
hold this content.

The only exception is in the !DT case, where the call chain to
at91sam926x_ioremap_pit and then at91sam926x_pit_init as init_time makes it
hard for the moment to pass the physical address of the timer.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/mach-at91/at91sam926x_time.c

@@ -20,6 +20,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
+#include <linux/slab.h>
 
 #include <mach/hardware.h>
 
@@ -39,19 +40,35 @@
 #define PIT_CPIV(x)	((x) & AT91_PIT_CPIV)
 #define PIT_PICNT(x)	(((x) & AT91_PIT_PICNT) >> 20)
 
-static u32 pit_cycle;		/* write-once */
-static u32 pit_cnt;		/* access only w/system irq blocked */
-static void __iomem *pit_base_addr __read_mostly;
-static struct clk *mck;
+struct pit_data {
+	struct clock_event_device	clkevt;
+	struct clocksource		clksrc;
 
-static inline unsigned int pit_read(unsigned int reg_offset)
+	void __iomem	*base;
+	u32		cycle;
+	u32		cnt;
+	unsigned int	irq;
+	struct clk	*mck;
+};
+
+static inline struct pit_data *clksrc_to_pit_data(struct clocksource *clksrc)
 {
-	return __raw_readl(pit_base_addr + reg_offset);
+	return container_of(clksrc, struct pit_data, clksrc);
 }
 
-static inline void pit_write(unsigned int reg_offset, unsigned long value)
+static inline struct pit_data *clkevt_to_pit_data(struct clock_event_device *clkevt)
 {
-	__raw_writel(value, pit_base_addr + reg_offset);
+	return container_of(clkevt, struct pit_data, clkevt);
+}
+
+static inline unsigned int pit_read(void __iomem *base, unsigned int reg_offset)
+{
+	return __raw_readl(base + reg_offset);
+}
+
+static inline void pit_write(void __iomem *base, unsigned int reg_offset, unsigned long value)
+{
+	__raw_writel(value, base + reg_offset);
 }
 
 /*
@@ -60,40 +77,35 @@ static inline void pit_write(unsigned int reg_offset, unsigned long value)
  */
 static cycle_t read_pit_clk(struct clocksource *cs)
 {
+	struct pit_data *data = clksrc_to_pit_data(cs);
 	unsigned long flags;
 	u32 elapsed;
 	u32 t;
 
 	raw_local_irq_save(flags);
-	elapsed = pit_cnt;
-	t = pit_read(AT91_PIT_PIIR);
+	elapsed = data->cnt;
+	t = pit_read(data->base, AT91_PIT_PIIR);
 	raw_local_irq_restore(flags);
 
-	elapsed += PIT_PICNT(t) * pit_cycle;
+	elapsed += PIT_PICNT(t) * data->cycle;
 	elapsed += PIT_CPIV(t);
 	return elapsed;
 }
 
-static struct clocksource pit_clk = {
-	.name		= "pit",
-	.rating		= 175,
-	.read		= read_pit_clk,
-	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
-};
-
-
 /*
  * Clockevent device:  interrupts every 1/HZ (== pit_cycles * MCK/16)
  */
 static void
 pit_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev)
 {
+	struct pit_data *data = clkevt_to_pit_data(dev);
+
 	switch (mode) {
 	case CLOCK_EVT_MODE_PERIODIC:
 		/* update clocksource counter */
-		pit_cnt += pit_cycle * PIT_PICNT(pit_read(AT91_PIT_PIVR));
-		pit_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN
-				| AT91_PIT_PITIEN);
+		data->cnt += data->cycle * PIT_PICNT(pit_read(data->base, AT91_PIT_PIVR));
+		pit_write(data->base, AT91_PIT_MR,
+			  (data->cycle - 1) | AT91_PIT_PITEN | AT91_PIT_PITIEN);
 		break;
 	case CLOCK_EVT_MODE_ONESHOT:
 		BUG();
@@ -101,7 +113,8 @@ pit_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev)
 	case CLOCK_EVT_MODE_SHUTDOWN:
 	case CLOCK_EVT_MODE_UNUSED:
 		/* disable irq, leaving the clocksource active */
-		pit_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN);
+		pit_write(data->base, AT91_PIT_MR,
+			  (data->cycle - 1) | AT91_PIT_PITEN);
 		break;
 	case CLOCK_EVT_MODE_RESUME:
 		break;
@@ -110,44 +123,40 @@ pit_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev)
 
 static void at91sam926x_pit_suspend(struct clock_event_device *cedev)
 {
+	struct pit_data *data = clkevt_to_pit_data(cedev);
+
 	/* Disable timer */
-	pit_write(AT91_PIT_MR, 0);
+	pit_write(data->base, AT91_PIT_MR, 0);
 }
 
-static void at91sam926x_pit_reset(void)
+static void at91sam926x_pit_reset(struct pit_data *data)
 {
 	/* Disable timer and irqs */
-	pit_write(AT91_PIT_MR, 0);
+	pit_write(data->base, AT91_PIT_MR, 0);
 
 	/* Clear any pending interrupts, wait for PIT to stop counting */
-	while (PIT_CPIV(pit_read(AT91_PIT_PIVR)) != 0)
+	while (PIT_CPIV(pit_read(data->base, AT91_PIT_PIVR)) != 0)
 		cpu_relax();
 
 	/* Start PIT but don't enable IRQ */
-	pit_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN);
+	pit_write(data->base, AT91_PIT_MR,
+		  (data->cycle - 1) | AT91_PIT_PITEN);
 }
 
 static void at91sam926x_pit_resume(struct clock_event_device *cedev)
 {
-	at91sam926x_pit_reset();
-}
-
-static struct clock_event_device pit_clkevt = {
-	.name		= "pit",
-	.features	= CLOCK_EVT_FEAT_PERIODIC,
-	.shift		= 32,
-	.rating		= 100,
-	.set_mode	= pit_clkevt_mode,
-	.suspend	= at91sam926x_pit_suspend,
-	.resume		= at91sam926x_pit_resume,
-};
+	struct pit_data *data = clkevt_to_pit_data(cedev);
 
+	at91sam926x_pit_reset(data);
+}
 
 /*
  * IRQ handler for the timer.
  */
 static irqreturn_t at91sam926x_pit_interrupt(int irq, void *dev_id)
 {
+	struct pit_data *data = dev_id;
+
 	/*
 	 * irqs should be disabled here, but as the irq is shared they are only
 	 * guaranteed to be off if the timer irq is registered first.
@@ -155,15 +164,15 @@ static irqreturn_t at91sam926x_pit_interrupt(int irq, void *dev_id)
 	WARN_ON_ONCE(!irqs_disabled());
 
 	/* The PIT interrupt may be disabled, and is shared */
-	if ((pit_clkevt.mode == CLOCK_EVT_MODE_PERIODIC)
-			&& (pit_read(AT91_PIT_SR) & AT91_PIT_PITS)) {
+	if ((data->clkevt.mode == CLOCK_EVT_MODE_PERIODIC) &&
+	    (pit_read(data->base, AT91_PIT_SR) & AT91_PIT_PITS)) {
 		unsigned nr_ticks;
 
 		/* Get number of ticks performed before irq, and ack it */
-		nr_ticks = PIT_PICNT(pit_read(AT91_PIT_PIVR));
+		nr_ticks = PIT_PICNT(pit_read(data->base, AT91_PIT_PIVR));
 		do {
-			pit_cnt += pit_cycle;
-			pit_clkevt.event_handler(&pit_clkevt);
+			data->cnt += data->cycle;
+			data->clkevt.event_handler(&data->clkevt);
 			nr_ticks--;
 		} while (nr_ticks);
 
@@ -176,7 +185,7 @@ static irqreturn_t at91sam926x_pit_interrupt(int irq, void *dev_id)
 /*
  * Set up both clocksource and clockevent support.
  */
-static void __init at91sam926x_pit_common_init(unsigned int pit_irq)
+static void __init at91sam926x_pit_common_init(struct pit_data *data)
 {
 	unsigned long	pit_rate;
 	unsigned	bits;
@@ -186,67 +195,95 @@ static void __init at91sam926x_pit_common_init(unsigned int pit_irq)
 	 * Use our actual MCK to figure out how many MCK/16 ticks per
 	 * 1/HZ period (instead of a compile-time constant LATCH).
 	 */
-	pit_rate = clk_get_rate(mck) / 16;
-	pit_cycle = DIV_ROUND_CLOSEST(pit_rate, HZ);
-	WARN_ON(((pit_cycle - 1) & ~AT91_PIT_PIV) != 0);
+	pit_rate = clk_get_rate(data->mck) / 16;
+	data->cycle = DIV_ROUND_CLOSEST(pit_rate, HZ);
+	WARN_ON(((data->cycle - 1) & ~AT91_PIT_PIV) != 0);
 
 	/* Initialize and enable the timer */
-	at91sam926x_pit_reset();
+	at91sam926x_pit_reset(data);
 
 	/*
 	 * Register clocksource.  The high order bits of PIV are unused,
 	 * so this isn't a 32-bit counter unless we get clockevent irqs.
 	 */
-	bits = 12 /* PICNT */ + ilog2(pit_cycle) /* PIV */;
-	pit_clk.mask = CLOCKSOURCE_MASK(bits);
-	clocksource_register_hz(&pit_clk, pit_rate);
+	bits = 12 /* PICNT */ + ilog2(data->cycle) /* PIV */;
+	data->clksrc.mask = CLOCKSOURCE_MASK(bits);
+	data->clksrc.name = "pit";
+	data->clksrc.rating = 175;
+	data->clksrc.read = read_pit_clk,
+	data->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS,
+	clocksource_register_hz(&data->clksrc, pit_rate);
 
 	/* Set up irq handler */
-	ret = request_irq(pit_irq, at91sam926x_pit_interrupt,
+	ret = request_irq(data->irq, at91sam926x_pit_interrupt,
 			  IRQF_SHARED | IRQF_TIMER | IRQF_IRQPOLL,
-			  "at91_tick", pit_base_addr);
+			  "at91_tick", data);
 	if (ret)
 		panic(pr_fmt("Unable to setup IRQ\n"));
 
 	/* Set up and register clockevents */
-	pit_clkevt.mult = div_sc(pit_rate, NSEC_PER_SEC, pit_clkevt.shift);
-	pit_clkevt.cpumask = cpumask_of(0);
-	clockevents_register_device(&pit_clkevt);
+	data->clkevt.name = "pit";
+	data->clkevt.features = CLOCK_EVT_FEAT_PERIODIC;
+	data->clkevt.shift = 32;
+	data->clkevt.mult = div_sc(pit_rate, NSEC_PER_SEC, data->clkevt.shift);
+	data->clkevt.rating = 100;
+	data->clkevt.cpumask = cpumask_of(0);
+
+	data->clkevt.set_mode = pit_clkevt_mode;
+	data->clkevt.resume = at91sam926x_pit_resume;
+	data->clkevt.suspend = at91sam926x_pit_suspend;
+	clockevents_register_device(&data->clkevt);
 }
 
 static void __init at91sam926x_pit_dt_init(struct device_node *node)
 {
-	unsigned int irq;
+	struct pit_data *data;
 
-	pit_base_addr = of_iomap(node, 0);
-	if (!pit_base_addr)
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		panic(pr_fmt("Unable to allocate memory\n"));
+
+	data->base = of_iomap(node, 0);
+	if (!data->base)
 		panic(pr_fmt("Could not map PIT address\n"));
 
-	mck = of_clk_get(node, 0);
-	if (IS_ERR(mck))
+	data->mck = of_clk_get(node, 0);
+	if (IS_ERR(data->mck))
 		/* Fallback on clkdev for !CCF-based boards */
-		mck = clk_get(NULL, "mck");
+		data->mck = clk_get(NULL, "mck");
 
-	if (IS_ERR(mck))
+	if (IS_ERR(data->mck))
 		panic(pr_fmt("Unable to get mck clk\n"));
 
 	/* Get the interrupts property */
-	irq = irq_of_parse_and_map(node, 0);
-	if (!irq)
+	data->irq = irq_of_parse_and_map(node, 0);
+	if (!data->irq)
 		panic(pr_fmt("Unable to get IRQ from DT\n"));
 
-	at91sam926x_pit_common_init(irq);
+	at91sam926x_pit_common_init(data);
 }
 CLOCKSOURCE_OF_DECLARE(at91sam926x_pit, "atmel,at91sam9260-pit",
 		       at91sam926x_pit_dt_init);
 
+static void __iomem *pit_base_addr;
+
 void __init at91sam926x_pit_init(void)
 {
-	mck = clk_get(NULL, "mck");
-	if (IS_ERR(mck))
+	struct pit_data *data;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		panic(pr_fmt("Unable to allocate memory\n"));
+
+	data->base = pit_base_addr;
+
+	data->mck = clk_get(NULL, "mck");
+	if (IS_ERR(data->mck))
 		panic(pr_fmt("Unable to get mck clk\n"));
 
-	at91sam926x_pit_common_init(NR_IRQS_LEGACY + AT91_ID_SYS);
+	data->irq = NR_IRQS_LEGACY + AT91_ID_SYS;
+
+	at91sam926x_pit_common_init(data);
 }
 
 void __init at91sam926x_ioremap_pit(u32 addr)