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path: root/drivers/clocksource/timer-atmel-tcb.c
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Diffstat (limited to 'drivers/clocksource/timer-atmel-tcb.c')
-rw-r--r--drivers/clocksource/timer-atmel-tcb.c103
1 files changed, 59 insertions, 44 deletions
diff --git a/drivers/clocksource/timer-atmel-tcb.c b/drivers/clocksource/timer-atmel-tcb.c
index 7427b07495a8..787dbebbb432 100644
--- a/drivers/clocksource/timer-atmel-tcb.c
+++ b/drivers/clocksource/timer-atmel-tcb.c
@@ -27,9 +27,10 @@
* - Some chips support 32 bit counter. A single channel is used for
* this 32 bit free-running counter. the second channel is not used.
*
- * - The third channel may be used to provide a 16-bit clockevent
- * source, used in either periodic or oneshot mode. This runs
- * at 32 KiHZ, and can handle delays of up to two seconds.
+ * - The third channel may be used to provide a clockevent source, used in
+ * either periodic or oneshot mode. For 16-bit counter its runs at 32 KiHZ,
+ * and can handle delays of up to two seconds. For 32-bit counters, it runs at
+ * the same rate as the clocksource
*
* REVISIT behavior during system suspend states... we should disable
* all clocks and save the power. Easily done for clockevent devices,
@@ -47,6 +48,8 @@ static struct
} tcb_cache[3];
static u32 bmr_cache;
+static const u8 atmel_tcb_divisors[] = { 2, 8, 32, 128 };
+
static u64 tc_get_cycles(struct clocksource *cs)
{
unsigned long flags;
@@ -143,6 +146,7 @@ static unsigned long notrace tc_delay_timer_read32(void)
struct tc_clkevt_device {
struct clock_event_device clkevt;
struct clk *clk;
+ u32 rate;
void __iomem *regs;
};
@@ -151,13 +155,6 @@ static struct tc_clkevt_device *to_tc_clkevt(struct clock_event_device *clkevt)
return container_of(clkevt, struct tc_clkevt_device, clkevt);
}
-/* For now, we always use the 32K clock ... this optimizes for NO_HZ,
- * because using one of the divided clocks would usually mean the
- * tick rate can never be less than several dozen Hz (vs 0.5 Hz).
- *
- * A divided clock could be good for high resolution timers, since
- * 30.5 usec resolution can seem "low".
- */
static u32 timer_clock;
static int tc_shutdown(struct clock_event_device *d)
@@ -183,7 +180,7 @@ static int tc_set_oneshot(struct clock_event_device *d)
clk_enable(tcd->clk);
- /* slow clock, count up to RC, then irq and stop */
+ /* count up to RC, then irq and stop */
writel(timer_clock | ATMEL_TC_CPCSTOP | ATMEL_TC_WAVE |
ATMEL_TC_WAVESEL_UP_AUTO, regs + ATMEL_TC_REG(2, CMR));
writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
@@ -205,10 +202,10 @@ static int tc_set_periodic(struct clock_event_device *d)
*/
clk_enable(tcd->clk);
- /* slow clock, count up to RC, then irq and restart */
+ /* count up to RC, then irq and restart */
writel(timer_clock | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
regs + ATMEL_TC_REG(2, CMR));
- writel((32768 + HZ / 2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));
+ writel((tcd->rate + HZ / 2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));
/* Enable clock and interrupts on RC compare */
writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
@@ -256,47 +253,55 @@ static irqreturn_t ch2_irq(int irq, void *handle)
return IRQ_NONE;
}
-static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
+static int __init setup_clkevents(struct atmel_tc *tc, int divisor_idx)
{
int ret;
struct clk *t2_clk = tc->clk[2];
int irq = tc->irq[2];
-
- ret = clk_prepare_enable(tc->slow_clk);
- if (ret)
- return ret;
+ int bits = tc->tcb_config->counter_width;
/* try to enable t2 clk to avoid future errors in mode change */
ret = clk_prepare_enable(t2_clk);
- if (ret) {
- clk_disable_unprepare(tc->slow_clk);
+ if (ret)
return ret;
- }
-
- clk_disable(t2_clk);
clkevt.regs = tc->regs;
clkevt.clk = t2_clk;
- timer_clock = clk32k_divisor_idx;
+ if (bits == 32) {
+ timer_clock = divisor_idx;
+ clkevt.rate = clk_get_rate(t2_clk) / atmel_tcb_divisors[divisor_idx];
+ } else {
+ ret = clk_prepare_enable(tc->slow_clk);
+ if (ret) {
+ clk_disable_unprepare(t2_clk);
+ return ret;
+ }
+
+ clkevt.rate = clk_get_rate(tc->slow_clk);
+ timer_clock = ATMEL_TC_TIMER_CLOCK5;
+ }
+
+ clk_disable(t2_clk);
clkevt.clkevt.cpumask = cpumask_of(0);
ret = request_irq(irq, ch2_irq, IRQF_TIMER, "tc_clkevt", &clkevt);
if (ret) {
clk_unprepare(t2_clk);
- clk_disable_unprepare(tc->slow_clk);
+ if (bits != 32)
+ clk_disable_unprepare(tc->slow_clk);
return ret;
}
- clockevents_config_and_register(&clkevt.clkevt, 32768, 1, 0xffff);
+ clockevents_config_and_register(&clkevt.clkevt, clkevt.rate, 1, BIT(bits) - 1);
return ret;
}
#else /* !CONFIG_GENERIC_CLOCKEVENTS */
-static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
+static int __init setup_clkevents(struct atmel_tc *tc, int divisor_idx)
{
/* NOTHING */
return 0;
@@ -346,11 +351,23 @@ static void __init tcb_setup_single_chan(struct atmel_tc *tc, int mck_divisor_id
writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
}
-static const u8 atmel_tcb_divisors[5] = { 2, 8, 32, 128, 0, };
+static struct atmel_tcb_config tcb_rm9200_config = {
+ .counter_width = 16,
+};
+
+static struct atmel_tcb_config tcb_sam9x5_config = {
+ .counter_width = 32,
+};
+
+static struct atmel_tcb_config tcb_sama5d2_config = {
+ .counter_width = 32,
+ .has_gclk = 1,
+};
static const struct of_device_id atmel_tcb_of_match[] = {
- { .compatible = "atmel,at91rm9200-tcb", .data = (void *)16, },
- { .compatible = "atmel,at91sam9x5-tcb", .data = (void *)32, },
+ { .compatible = "atmel,at91rm9200-tcb", .data = &tcb_rm9200_config, },
+ { .compatible = "atmel,at91sam9x5-tcb", .data = &tcb_sam9x5_config, },
+ { .compatible = "atmel,sama5d2-tcb", .data = &tcb_sama5d2_config, },
{ /* sentinel */ }
};
@@ -362,7 +379,6 @@ static int __init tcb_clksrc_init(struct device_node *node)
u64 (*tc_sched_clock)(void);
u32 rate, divided_rate = 0;
int best_divisor_idx = -1;
- int clk32k_divisor_idx = -1;
int bits;
int i;
int ret;
@@ -399,7 +415,11 @@ static int __init tcb_clksrc_init(struct device_node *node)
}
match = of_match_node(atmel_tcb_of_match, node->parent);
- bits = (uintptr_t)match->data;
+ if (!match)
+ return -ENODEV;
+
+ tc.tcb_config = match->data;
+ bits = tc.tcb_config->counter_width;
for (i = 0; i < ARRAY_SIZE(tc.irq); i++)
writel(ATMEL_TC_ALL_IRQ, tc.regs + ATMEL_TC_REG(i, IDR));
@@ -412,22 +432,17 @@ static int __init tcb_clksrc_init(struct device_node *node)
/* How fast will we be counting? Pick something over 5 MHz. */
rate = (u32) clk_get_rate(t0_clk);
- for (i = 0; i < ARRAY_SIZE(atmel_tcb_divisors); i++) {
+ i = 0;
+ if (tc.tcb_config->has_gclk)
+ i = 1;
+ for (; i < ARRAY_SIZE(atmel_tcb_divisors); i++) {
unsigned divisor = atmel_tcb_divisors[i];
unsigned tmp;
- /* remember 32 KiHz clock for later */
- if (!divisor) {
- clk32k_divisor_idx = i;
- continue;
- }
-
tmp = rate / divisor;
pr_debug("TC: %u / %-3u [%d] --> %u\n", rate, divisor, i, tmp);
- if (best_divisor_idx > 0) {
- if (tmp < 5 * 1000 * 1000)
- continue;
- }
+ if ((best_divisor_idx >= 0) && (tmp < 5 * 1000 * 1000))
+ break;
divided_rate = tmp;
best_divisor_idx = i;
}
@@ -467,7 +482,7 @@ static int __init tcb_clksrc_init(struct device_node *node)
goto err_disable_t1;
/* channel 2: periodic and oneshot timer support */
- ret = setup_clkevents(&tc, clk32k_divisor_idx);
+ ret = setup_clkevents(&tc, best_divisor_idx);
if (ret)
goto err_unregister_clksrc;