[PATCH 2/4] irqchip: imgpdc: Avoid immediate wake event during set_wake

Ed Blake
2017-10-02T09:57:17Z

When enabling sys wakes, an immediate power transition may occur if the
wake input has been active in the past. Work around this by doing the
following:

1) Set SYS_WAKE_CONFIG to the current value of SOC_POWER so that an
immediate power transition has no effect
2) Enable and disable the sys wake to flush the stale wake event
3) Set SYS_WAKE_CONFIG back to the original value

Signed-off-by: Ed Blake <ed.blake@sondrel.com>
---
drivers/irqchip/irq-imgpdc.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)

diff --git a/drivers/irqchip/irq-imgpdc.c b/drivers/irqchip/irq-imgpdc.c
index 2ac3210..22d8f8a 100644
--- a/drivers/irqchip/irq-imgpdc.c
+++ b/drivers/irqchip/irq-imgpdc.c
@@ -8,6 +8,7 @@
*/

#include <linux/bitops.h>
+#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/io.h>
@@ -18,6 +19,7 @@

/* PDC interrupt register numbers */

+#define PDC_SOC_POWER 0x300
#define PDC_IRQ_STATUS 0x310
#define PDC_IRQ_ENABLE 0x314
#define PDC_IRQ_CLEAR 0x318
@@ -204,6 +206,8 @@ static int pdc_irq_set_wake(struct irq_data *data, unsigned int on)
unsigned int mask = (1 << 16) << hw;
unsigned int dst_irq;
unsigned int *dst_irq_wake_depth;
+ unsigned int syswake, soc_sys_wake_cfg_regoff;
+ u32 soc_sys_wake_cfg, soc_power;
int ret;

/* control the destination IRQ wakeup too for standby mode */
@@ -216,6 +220,27 @@ static int pdc_irq_set_wake(struct irq_data *data, unsigned int on)
}

raw_spin_lock(&priv->lock);
+ /*
+ * When enabling sys wakes, an immediate power transition may occur if
+ * the wake input has been active in the past. Work around this:
+ * 1) Set SYS_WAKE_CONFIG to the current value of SOC_POWER so that an
+ * immediate power transition has no effect
+ * 2) Enable and disable the sys wake to flush the stale wake event
+ * 3) Set SYS_WAKE_CONFIG back to the original value
+ */
+ if (hwirq_is_syswake(hw) && on) {
+ syswake = hwirq_to_syswake(hw);
+ soc_sys_wake_cfg_regoff = PDC_SYS_WAKE_CONFIG_BASE +
+ syswake * PDC_SYS_WAKE_CONFIG_STRIDE;
+ soc_sys_wake_cfg = pdc_read(priv, soc_sys_wake_cfg_regoff);
+ soc_power = pdc_read(priv, PDC_SOC_POWER);
+ pdc_write(priv, soc_sys_wake_cfg_regoff, soc_power);
+ pdc_write(priv, PDC_IRQ_ROUTE, priv->irq_route | mask);
+ udelay(31);
+ pdc_write(priv, PDC_IRQ_ROUTE, priv->irq_route);
+ pdc_write(priv, soc_sys_wake_cfg_regoff, soc_sys_wake_cfg);
+ }
+
if (on)
priv->irq_route |= mask;
else
--
1.9.1