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 <[email protected]>
---
 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

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