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clocksource/drivers/tcb_clksrc: Save timer context on suspend/resume

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On sama5d2, power to the core may be cut while entering suspend mode. It is
necessary to save and restore the TCB registers.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
This commit is contained in:
Alexandre Belloni 2017-05-12 20:22:51 +02:00 committed by Daniel Lezcano
parent 740e237add
commit 2a515e5d7c
1 changed files with 51 additions and 0 deletions
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51
drivers/clocksource/tcb_clksrc.c
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@ -9,6 +9,7 @@
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/syscore_ops.h>
#include <linux/atmel_tc.h>
@ -40,6 +41,14 @@
*/
static void __iomem *tcaddr;
static struct
{
u32 cmr;
u32 imr;
u32 rc;
bool clken;
} tcb_cache[3];
static u32 bmr_cache;
static u64 tc_get_cycles(struct clocksource *cs)
{
@ -61,12 +70,54 @@ static u64 tc_get_cycles32(struct clocksource *cs)
return __raw_readl(tcaddr + ATMEL_TC_REG(0, CV));
}
void tc_clksrc_suspend(struct clocksource *cs)
{
int i;
for (i = 0; i < ARRAY_SIZE(tcb_cache); i++) {
tcb_cache[i].cmr = readl(tcaddr + ATMEL_TC_REG(i, CMR));
tcb_cache[i].imr = readl(tcaddr + ATMEL_TC_REG(i, IMR));
tcb_cache[i].rc = readl(tcaddr + ATMEL_TC_REG(i, RC));
tcb_cache[i].clken = !!(readl(tcaddr + ATMEL_TC_REG(i, SR)) &
ATMEL_TC_CLKSTA);
}
bmr_cache = readl(tcaddr + ATMEL_TC_BMR);
}
void tc_clksrc_resume(struct clocksource *cs)
{
int i;
for (i = 0; i < ARRAY_SIZE(tcb_cache); i++) {
/* Restore registers for the channel, RA and RB are not used */
writel(tcb_cache[i].cmr, tcaddr + ATMEL_TC_REG(i, CMR));
writel(tcb_cache[i].rc, tcaddr + ATMEL_TC_REG(i, RC));
writel(0, tcaddr + ATMEL_TC_REG(i, RA));
writel(0, tcaddr + ATMEL_TC_REG(i, RB));
/* Disable all the interrupts */
writel(0xff, tcaddr + ATMEL_TC_REG(i, IDR));
/* Reenable interrupts that were enabled before suspending */
writel(tcb_cache[i].imr, tcaddr + ATMEL_TC_REG(i, IER));
/* Start the clock if it was used */
if (tcb_cache[i].clken)
writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(i, CCR));
}
/* Dual channel, chain channels */
writel(bmr_cache, tcaddr + ATMEL_TC_BMR);
/* Finally, trigger all the channels*/
writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
}
static struct clocksource clksrc = {
.name = "tcb_clksrc",
.rating = 200,
.read = tc_get_cycles,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.suspend = tc_clksrc_suspend,
.resume = tc_clksrc_resume,
};
#ifdef CONFIG_GENERIC_CLOCKEVENTS