1 files changed, 123 insertions, 93 deletions

diff --git a/drivers/clocksource/sh_cmt.c b/drivers/clocksource/sh_cmt.c
index 64dcb082d4cf..791b298c995b 100644
--- a/drivers/clocksource/sh_cmt.c
+++ b/drivers/clocksource/sh_cmt.c
@@ -13,11 +13,11 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/ioport.h>
 #include <linux/irq.h>
 #include <linux/module.h>
 #include <linux/of.h>
-#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
@@ -116,6 +116,7 @@ struct sh_cmt_device {
 	void __iomem *mapbase;
 	struct clk *clk;
 	unsigned long rate;
+	unsigned int reg_delay;
 
 	raw_spinlock_t lock; /* Protect the shared start/stop register */
 
@@ -247,10 +248,17 @@ static inline u32 sh_cmt_read_cmstr(struct sh_cmt_channel *ch)
 
 static inline void sh_cmt_write_cmstr(struct sh_cmt_channel *ch, u32 value)
 {
-	if (ch->iostart)
-		ch->cmt->info->write_control(ch->iostart, 0, value);
-	else
-		ch->cmt->info->write_control(ch->cmt->mapbase, 0, value);
+	u32 old_value = sh_cmt_read_cmstr(ch);
+
+	if (value != old_value) {
+		if (ch->iostart) {
+			ch->cmt->info->write_control(ch->iostart, 0, value);
+			udelay(ch->cmt->reg_delay);
+		} else {
+			ch->cmt->info->write_control(ch->cmt->mapbase, 0, value);
+			udelay(ch->cmt->reg_delay);
+		}
+	}
 }
 
 static inline u32 sh_cmt_read_cmcsr(struct sh_cmt_channel *ch)
@@ -260,7 +268,12 @@ static inline u32 sh_cmt_read_cmcsr(struct sh_cmt_channel *ch)
 
 static inline void sh_cmt_write_cmcsr(struct sh_cmt_channel *ch, u32 value)
 {
-	ch->cmt->info->write_control(ch->ioctrl, CMCSR, value);
+	u32 old_value = sh_cmt_read_cmcsr(ch);
+
+	if (value != old_value) {
+		ch->cmt->info->write_control(ch->ioctrl, CMCSR, value);
+		udelay(ch->cmt->reg_delay);
+	}
 }
 
 static inline u32 sh_cmt_read_cmcnt(struct sh_cmt_channel *ch)
@@ -268,14 +281,33 @@ static inline u32 sh_cmt_read_cmcnt(struct sh_cmt_channel *ch)
 	return ch->cmt->info->read_count(ch->ioctrl, CMCNT);
 }
 
-static inline void sh_cmt_write_cmcnt(struct sh_cmt_channel *ch, u32 value)
+static inline int sh_cmt_write_cmcnt(struct sh_cmt_channel *ch, u32 value)
 {
+	/* Tests showed that we need to wait 3 clocks here */
+	unsigned int cmcnt_delay = DIV_ROUND_UP(3 * ch->cmt->reg_delay, 2);
+	u32 reg;
+
+	if (ch->cmt->info->model > SH_CMT_16BIT) {
+		int ret = read_poll_timeout_atomic(sh_cmt_read_cmcsr, reg,
+						   !(reg & SH_CMT32_CMCSR_WRFLG),
+						   1, cmcnt_delay, false, ch);
+		if (ret < 0)
+			return ret;
+	}
+
 	ch->cmt->info->write_count(ch->ioctrl, CMCNT, value);
+	udelay(cmcnt_delay);
+	return 0;
 }
 
 static inline void sh_cmt_write_cmcor(struct sh_cmt_channel *ch, u32 value)
 {
-	ch->cmt->info->write_count(ch->ioctrl, CMCOR, value);
+	u32 old_value = ch->cmt->info->read_count(ch->ioctrl, CMCOR);
+
+	if (value != old_value) {
+		ch->cmt->info->write_count(ch->ioctrl, CMCOR, value);
+		udelay(ch->cmt->reg_delay);
+	}
 }
 
 static u32 sh_cmt_get_counter(struct sh_cmt_channel *ch, u32 *has_wrapped)
@@ -319,18 +351,10 @@ static void sh_cmt_start_stop_ch(struct sh_cmt_channel *ch, int start)
 
 static int sh_cmt_enable(struct sh_cmt_channel *ch)
 {
-	int k, ret;
+	int ret;
 
 	dev_pm_syscore_device(&ch->cmt->pdev->dev, true);
 
-	/* enable clock */
-	ret = clk_enable(ch->cmt->clk);
-	if (ret) {
-		dev_err(&ch->cmt->pdev->dev, "ch%u: cannot enable clock\n",
-			ch->index);
-		goto err0;
-	}
-
 	/* make sure channel is disabled */
 	sh_cmt_start_stop_ch(ch, 0);
 
@@ -347,41 +371,17 @@ static int sh_cmt_enable(struct sh_cmt_channel *ch)
 	}
 
 	sh_cmt_write_cmcor(ch, 0xffffffff);
-	sh_cmt_write_cmcnt(ch, 0);
+	ret = sh_cmt_write_cmcnt(ch, 0);
 
-	/*
-	 * According to the sh73a0 user's manual, as CMCNT can be operated
-	 * only by the RCLK (Pseudo 32 kHz), there's one restriction on
-	 * modifying CMCNT register; two RCLK cycles are necessary before
-	 * this register is either read or any modification of the value
-	 * it holds is reflected in the LSI's actual operation.
-	 *
-	 * While at it, we're supposed to clear out the CMCNT as of this
-	 * moment, so make sure it's processed properly here.  This will
-	 * take RCLKx2 at maximum.
-	 */
-	for (k = 0; k < 100; k++) {
-		if (!sh_cmt_read_cmcnt(ch))
-			break;
-		udelay(1);
-	}
-
-	if (sh_cmt_read_cmcnt(ch)) {
+	if (ret || sh_cmt_read_cmcnt(ch)) {
 		dev_err(&ch->cmt->pdev->dev, "ch%u: cannot clear CMCNT\n",
 			ch->index);
-		ret = -ETIMEDOUT;
-		goto err1;
+		return -ETIMEDOUT;
 	}
 
 	/* enable channel */
 	sh_cmt_start_stop_ch(ch, 1);
 	return 0;
- err1:
-	/* stop clock */
-	clk_disable(ch->cmt->clk);
-
- err0:
-	return ret;
 }
 
 static void sh_cmt_disable(struct sh_cmt_channel *ch)
@@ -392,9 +392,6 @@ static void sh_cmt_disable(struct sh_cmt_channel *ch)
 	/* disable interrupts in CMT block */
 	sh_cmt_write_cmcsr(ch, 0);
 
-	/* stop clock */
-	clk_disable(ch->cmt->clk);
-
 	dev_pm_syscore_device(&ch->cmt->pdev->dev, false);
 }
 
@@ -513,6 +510,7 @@ static void sh_cmt_set_next(struct sh_cmt_channel *ch, unsigned long delta)
 static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id)
 {
 	struct sh_cmt_channel *ch = dev_id;
+	unsigned long flags;
 
 	/* clear flags */
 	sh_cmt_write_cmcsr(ch, sh_cmt_read_cmcsr(ch) &
@@ -543,6 +541,8 @@ static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id)
 
 	ch->flags &= ~FLAG_SKIPEVENT;
 
+	raw_spin_lock_irqsave(&ch->lock, flags);
+
 	if (ch->flags & FLAG_REPROGRAM) {
 		ch->flags &= ~FLAG_REPROGRAM;
 		sh_cmt_clock_event_program_verify(ch, 1);
@@ -555,40 +555,73 @@ static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id)
 
 	ch->flags &= ~FLAG_IRQCONTEXT;
 
+	raw_spin_unlock_irqrestore(&ch->lock, flags);
+
 	return IRQ_HANDLED;
 }
 
-static int sh_cmt_start(struct sh_cmt_channel *ch, unsigned long flag)
+static int sh_cmt_start_clocksource(struct sh_cmt_channel *ch)
 {
 	int ret = 0;
 	unsigned long flags;
 
-	if (flag & FLAG_CLOCKSOURCE)
-		pm_runtime_get_sync(&ch->cmt->pdev->dev);
-
 	raw_spin_lock_irqsave(&ch->lock, flags);
 
-	if (!(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE))) {
-		if (flag & FLAG_CLOCKEVENT)
-			pm_runtime_get_sync(&ch->cmt->pdev->dev);
+	if (!(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
 		ret = sh_cmt_enable(ch);
-	}
 
 	if (ret)
 		goto out;
-	ch->flags |= flag;
+
+	ch->flags |= FLAG_CLOCKSOURCE;
 
 	/* setup timeout if no clockevent */
-	if (ch->cmt->num_channels == 1 &&
-	    flag == FLAG_CLOCKSOURCE && (!(ch->flags & FLAG_CLOCKEVENT)))
+	if (ch->cmt->num_channels == 1 && !(ch->flags & FLAG_CLOCKEVENT))
 		__sh_cmt_set_next(ch, ch->max_match_value);
+out:
+	raw_spin_unlock_irqrestore(&ch->lock, flags);
+
+	return ret;
+}
+
+static void sh_cmt_stop_clocksource(struct sh_cmt_channel *ch)
+{
+	unsigned long flags;
+	unsigned long f;
+
+	raw_spin_lock_irqsave(&ch->lock, flags);
+
+	f = ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE);
+
+	ch->flags &= ~FLAG_CLOCKSOURCE;
+
+	if (f && !(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
+		sh_cmt_disable(ch);
+
+	raw_spin_unlock_irqrestore(&ch->lock, flags);
+}
+
+static int sh_cmt_start_clockevent(struct sh_cmt_channel *ch)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&ch->lock, flags);
+
+	if (!(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
+		ret = sh_cmt_enable(ch);
+
+	if (ret)
+		goto out;
+
+	ch->flags |= FLAG_CLOCKEVENT;
  out:
 	raw_spin_unlock_irqrestore(&ch->lock, flags);
 
 	return ret;
 }
 
-static void sh_cmt_stop(struct sh_cmt_channel *ch, unsigned long flag)
+static void sh_cmt_stop_clockevent(struct sh_cmt_channel *ch)
 {
 	unsigned long flags;
 	unsigned long f;
@@ -596,22 +629,17 @@ static void sh_cmt_stop(struct sh_cmt_channel *ch, unsigned long flag)
 	raw_spin_lock_irqsave(&ch->lock, flags);
 
 	f = ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE);
-	ch->flags &= ~flag;
 
-	if (f && !(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE))) {
+	ch->flags &= ~FLAG_CLOCKEVENT;
+
+	if (f && !(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
 		sh_cmt_disable(ch);
-		if (flag & FLAG_CLOCKEVENT)
-			pm_runtime_put(&ch->cmt->pdev->dev);
-	}
 
 	/* adjust the timeout to maximum if only clocksource left */
-	if ((flag == FLAG_CLOCKEVENT) && (ch->flags & FLAG_CLOCKSOURCE))
+	if (ch->flags & FLAG_CLOCKSOURCE)
 		__sh_cmt_set_next(ch, ch->max_match_value);
 
 	raw_spin_unlock_irqrestore(&ch->lock, flags);
-
-	if (flag & FLAG_CLOCKSOURCE)
-		pm_runtime_put(&ch->cmt->pdev->dev);
 }
 
 static struct sh_cmt_channel *cs_to_sh_cmt(struct clocksource *cs)
@@ -652,7 +680,7 @@ static int sh_cmt_clocksource_enable(struct clocksource *cs)
 
 	ch->total_cycles = 0;
 
-	ret = sh_cmt_start(ch, FLAG_CLOCKSOURCE);
+	ret = sh_cmt_start_clocksource(ch);
 	if (!ret)
 		ch->cs_enabled = true;
 
@@ -665,7 +693,7 @@ static void sh_cmt_clocksource_disable(struct clocksource *cs)
 
 	WARN_ON(!ch->cs_enabled);
 
-	sh_cmt_stop(ch, FLAG_CLOCKSOURCE);
+	sh_cmt_stop_clocksource(ch);
 	ch->cs_enabled = false;
 }
 
@@ -676,7 +704,7 @@ static void sh_cmt_clocksource_suspend(struct clocksource *cs)
 	if (!ch->cs_enabled)
 		return;
 
-	sh_cmt_stop(ch, FLAG_CLOCKSOURCE);
+	sh_cmt_stop_clocksource(ch);
 	dev_pm_genpd_suspend(&ch->cmt->pdev->dev);
 }
 
@@ -688,7 +716,7 @@ static void sh_cmt_clocksource_resume(struct clocksource *cs)
 		return;
 
 	dev_pm_genpd_resume(&ch->cmt->pdev->dev);
-	sh_cmt_start(ch, FLAG_CLOCKSOURCE);
+	sh_cmt_start_clocksource(ch);
 }
 
 static int sh_cmt_register_clocksource(struct sh_cmt_channel *ch,
@@ -720,7 +748,7 @@ static struct sh_cmt_channel *ced_to_sh_cmt(struct clock_event_device *ced)
 
 static void sh_cmt_clock_event_start(struct sh_cmt_channel *ch, int periodic)
 {
-	sh_cmt_start(ch, FLAG_CLOCKEVENT);
+	sh_cmt_start_clockevent(ch);
 
 	if (periodic)
 		sh_cmt_set_next(ch, ((ch->cmt->rate + HZ/2) / HZ) - 1);
@@ -732,7 +760,7 @@ static int sh_cmt_clock_event_shutdown(struct clock_event_device *ced)
 {
 	struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
 
-	sh_cmt_stop(ch, FLAG_CLOCKEVENT);
+	sh_cmt_stop_clockevent(ch);
 	return 0;
 }
 
@@ -743,7 +771,7 @@ static int sh_cmt_clock_event_set_state(struct clock_event_device *ced,
 
 	/* deal with old setting first */
 	if (clockevent_state_oneshot(ced) || clockevent_state_periodic(ced))
-		sh_cmt_stop(ch, FLAG_CLOCKEVENT);
+		sh_cmt_stop_clockevent(ch);
 
 	dev_info(&ch->cmt->pdev->dev, "ch%u: used for %s clock events\n",
 		 ch->index, periodic ? "periodic" : "oneshot");
@@ -765,12 +793,18 @@ static int sh_cmt_clock_event_next(unsigned long delta,
 				   struct clock_event_device *ced)
 {
 	struct sh_cmt_channel *ch = ced_to_sh_cmt(ced);
+	unsigned long flags;
 
 	BUG_ON(!clockevent_state_oneshot(ced));
+
+	raw_spin_lock_irqsave(&ch->lock, flags);
+
 	if (likely(ch->flags & FLAG_IRQCONTEXT))
 		ch->next_match_value = delta - 1;
 	else
-		sh_cmt_set_next(ch, delta - 1);
+		__sh_cmt_set_next(ch, delta - 1);
+
+	raw_spin_unlock_irqrestore(&ch->lock, flags);
 
 	return 0;
 }
@@ -995,8 +1029,8 @@ MODULE_DEVICE_TABLE(of, sh_cmt_of_table);
 
 static int sh_cmt_setup(struct sh_cmt_device *cmt, struct platform_device *pdev)
 {
-	unsigned int mask;
-	unsigned int i;
+	unsigned int mask, i;
+	unsigned long rate;
 	int ret;
 
 	cmt->pdev = pdev;
@@ -1032,10 +1066,16 @@ static int sh_cmt_setup(struct sh_cmt_device *cmt, struct platform_device *pdev)
 	if (ret < 0)
 		goto err_clk_unprepare;
 
-	if (cmt->info->width == 16)
-		cmt->rate = clk_get_rate(cmt->clk) / 512;
-	else
-		cmt->rate = clk_get_rate(cmt->clk) / 8;
+	rate = clk_get_rate(cmt->clk);
+	if (!rate) {
+		ret = -EINVAL;
+		goto err_clk_disable;
+	}
+
+	/* We shall wait 2 input clks after register writes */
+	if (cmt->info->model >= SH_CMT_48BIT)
+		cmt->reg_delay = DIV_ROUND_UP(2UL * USEC_PER_SEC, rate);
+	cmt->rate = rate / (cmt->info->width == 16 ? 512 : 8);
 
 	/* Map the memory resource(s). */
 	ret = sh_cmt_map_memory(cmt);
@@ -1068,8 +1108,6 @@ static int sh_cmt_setup(struct sh_cmt_device *cmt, struct platform_device *pdev)
 		mask &= ~(1 << hwidx);
 	}
 
-	clk_disable(cmt->clk);
-
 	platform_set_drvdata(pdev, cmt);
 
 	return 0;
@@ -1117,23 +1155,16 @@ static int sh_cmt_probe(struct platform_device *pdev)
  out:
 	if (cmt->has_clockevent || cmt->has_clocksource)
 		pm_runtime_irq_safe(&pdev->dev);
-	else
-		pm_runtime_idle(&pdev->dev);
 
 	return 0;
 }
 
-static int sh_cmt_remove(struct platform_device *pdev)
-{
-	return -EBUSY; /* cannot unregister clockevent and clocksource */
-}
-
 static struct platform_driver sh_cmt_device_driver = {
 	.probe		= sh_cmt_probe,
-	.remove		= sh_cmt_remove,
 	.driver		= {
 		.name	= "sh_cmt",
 		.of_match_table = of_match_ptr(sh_cmt_of_table),
+		.suppress_bind_attrs = true,
 	},
 	.id_table	= sh_cmt_id_table,
 };
@@ -1157,4 +1188,3 @@ module_exit(sh_cmt_exit);
 
 MODULE_AUTHOR("Magnus Damm");
 MODULE_DESCRIPTION("SuperH CMT Timer Driver");
-MODULE_LICENSE("GPL v2");