pinctrl: samsung: Write external wakeup interrupt mask

The pinctrl driver defines an IRQ chip which handles external wakeup
interrupts, therefore from logical point of view, it is the owner of
external interrupt mask.  The register controlling the mask belongs to
Power Management Unit address space so it has to be accessed with PMU
syscon regmap handle.

This mask should be written to hardware during system suspend.  Till now
ARMv7 machine code was responsible for this which created a dependency
between pin controller driver and arch/arm/mach code.

Try to rework this dependency so the pinctrl driver will write external
wakeup interrupt mask during late suspend.

Impact on ARMv7 designs (S5Pv210 and Exynos)
============================================
This duplicates setting mask with existing machine code
arch/arm/mach-exynos/suspend.c and arch/arm/mach-s5pv210/pm.c but it is
not a problem - the wakeup mask register will be written twice.  The
machine code will be cleaned up later.

The difference between implementation here and ARMv7 machine code
(arch/arm/mach-*) is the time of writing the mask:
1. The machine code is writing the mask quite late during system suspend
   path, after offlining secondary CPUs and just before doing actual
   suspend.
2. The implementation in pinctrl driver uses late suspend ops, therefore it
   will write the mask much earlier.  Hopefully late enough, after all
   drivers will enable or disable their interrupt wakeups
   (enable_irq_wake() etc).

Impact on ARMv8 designs (Exynos5433 and Exynos7)
================================================
The Suspend to RAM was not supported and external wakeup interrupt mask
was not written to HW.  This change brings us one step closer to
supporting Suspend to RAM.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Tomasz Figa <tomasz.figa@gmail.com>
Cc: Sylwester Nawrocki <snawrocki@kernel.org>
Acked-by: Tomasz Figa <tomasz.figa@gmail.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

drivers/pinctrl/samsung/pinctrl-exynos.c

@@ -25,6 +25,7 @@
 #include <linux/regmap.h>
 #include <linux/err.h>
 #include <linux/soc/samsung/exynos-pmu.h>
+#include <linux/soc/samsung/exynos-regs-pmu.h>
 
 #include <dt-bindings/pinctrl/samsung.h>
 
@@ -37,6 +38,8 @@ struct exynos_irq_chip {
 	u32 eint_con;
 	u32 eint_mask;
 	u32 eint_pend;
+	u32 eint_wake_mask_value;
+	u32 eint_wake_mask_reg;
 };
 
 static inline struct exynos_irq_chip *to_exynos_irq_chip(struct irq_chip *chip)
@@ -215,6 +218,7 @@ static struct exynos_irq_chip exynos_gpio_irq_chip = {
 	.eint_con = EXYNOS_GPIO_ECON_OFFSET,
 	.eint_mask = EXYNOS_GPIO_EMASK_OFFSET,
 	.eint_pend = EXYNOS_GPIO_EPEND_OFFSET,
+	/* eint_wake_mask_value not used */
 };
 
 static int exynos_eint_irq_map(struct irq_domain *h, unsigned int virq,
@@ -330,6 +334,8 @@ u32 exynos_get_eint_wake_mask(void)
 
 static int exynos_wkup_irq_set_wake(struct irq_data *irqd, unsigned int on)
 {
+	struct irq_chip *chip = irq_data_get_irq_chip(irqd);
+	struct exynos_irq_chip *our_chip = to_exynos_irq_chip(chip);
 	struct samsung_pin_bank *bank = irq_data_get_irq_chip_data(irqd);
 	unsigned long bit = 1UL << (2 * bank->eint_offset + irqd->hwirq);
 
@@ -339,6 +345,7 @@ static int exynos_wkup_irq_set_wake(struct irq_data *irqd, unsigned int on)
 		exynos_eint_wake_mask |= bit;
 	else
 		exynos_eint_wake_mask &= ~bit;
+	our_chip->eint_wake_mask_value = exynos_eint_wake_mask;
 
 	return 0;
 }
@@ -360,6 +367,9 @@ static const struct exynos_irq_chip s5pv210_wkup_irq_chip __initconst = {
 	.eint_con = EXYNOS_WKUP_ECON_OFFSET,
 	.eint_mask = EXYNOS_WKUP_EMASK_OFFSET,
 	.eint_pend = EXYNOS_WKUP_EPEND_OFFSET,
+	.eint_wake_mask_value = EXYNOS_EINT_WAKEUP_MASK_DISABLED,
+	/* Only difference with exynos4210_wkup_irq_chip: */
+	.eint_wake_mask_reg = S5PV210_EINT_WAKEUP_MASK,
 };
 
 static const struct exynos_irq_chip exynos4210_wkup_irq_chip __initconst = {
@@ -376,6 +386,8 @@ static const struct exynos_irq_chip exynos4210_wkup_irq_chip __initconst = {
 	.eint_con = EXYNOS_WKUP_ECON_OFFSET,
 	.eint_mask = EXYNOS_WKUP_EMASK_OFFSET,
 	.eint_pend = EXYNOS_WKUP_EPEND_OFFSET,
+	.eint_wake_mask_value = EXYNOS_EINT_WAKEUP_MASK_DISABLED,
+	.eint_wake_mask_reg = EXYNOS_EINT_WAKEUP_MASK,
 };
 
 static const struct exynos_irq_chip exynos7_wkup_irq_chip __initconst = {
@@ -392,6 +404,8 @@ static const struct exynos_irq_chip exynos7_wkup_irq_chip __initconst = {
 	.eint_con = EXYNOS7_WKUP_ECON_OFFSET,
 	.eint_mask = EXYNOS7_WKUP_EMASK_OFFSET,
 	.eint_pend = EXYNOS7_WKUP_EPEND_OFFSET,
+	.eint_wake_mask_value = EXYNOS_EINT_WAKEUP_MASK_DISABLED,
+	.eint_wake_mask_reg = EXYNOS5433_EINT_WAKEUP_MASK,
 };
 
 /* list of external wakeup controllers supported */
@@ -560,6 +574,27 @@ int exynos_eint_wkup_init(struct samsung_pinctrl_drv_data *d)
 	return 0;
 }
 
+static void
+exynos_pinctrl_set_eint_wakeup_mask(struct samsung_pinctrl_drv_data *drvdata,
+				    struct exynos_irq_chip *irq_chip)
+{
+	struct regmap *pmu_regs;
+
+	if (!drvdata->retention_ctrl || !drvdata->retention_ctrl->priv) {
+		dev_warn(drvdata->dev,
+			 "No retention data configured bank with external wakeup interrupt. Wake-up mask will not be set.\n");
+		return;
+	}
+
+	pmu_regs = drvdata->retention_ctrl->priv;
+	dev_info(drvdata->dev,
+		 "Setting external wakeup interrupt wakeup mask: 0x%x\n",
+		 irq_chip->eint_wake_mask_value);
+
+	regmap_write(pmu_regs, irq_chip->eint_wake_mask_reg,
+		     irq_chip->eint_wake_mask_value);
+}
+
 static void exynos_pinctrl_suspend_bank(
 				struct samsung_pinctrl_drv_data *drvdata,
 				struct samsung_pin_bank *bank)
@@ -582,11 +617,24 @@ static void exynos_pinctrl_suspend_bank(
 void exynos_pinctrl_suspend(struct samsung_pinctrl_drv_data *drvdata)
 {
 	struct samsung_pin_bank *bank = drvdata->pin_banks;
+	struct exynos_irq_chip *irq_chip = NULL;
 	int i;
 
-	for (i = 0; i < drvdata->nr_banks; ++i, ++bank)
+	for (i = 0; i < drvdata->nr_banks; ++i, ++bank) {
 		if (bank->eint_type == EINT_TYPE_GPIO)
 			exynos_pinctrl_suspend_bank(drvdata, bank);
+		else if (bank->eint_type == EINT_TYPE_WKUP) {
+			if (!irq_chip) {
+				irq_chip = bank->irq_chip;
+				exynos_pinctrl_set_eint_wakeup_mask(drvdata,
+								    irq_chip);
+			} else if (bank->irq_chip != irq_chip) {
+				dev_warn(drvdata->dev,
+					 "More than one external wakeup interrupt chip configured (bank: %s). This is not supported by hardware nor by driver.\n",
+					 bank->name);
+			}
+		}
+	}
 }
 
 static void exynos_pinctrl_resume_bank(

drivers/pinctrl/samsung/pinctrl-samsung.h

@@ -227,6 +227,9 @@ struct samsung_retention_data {
  *	device suspend, see samsung_pinctrl_suspend()
  * @resume: platform specific resume callback, executed during pin controller
  *	device suspend, see samsung_pinctrl_resume()
+ *
+ * External wakeup interrupts must define at least eint_wkup_init,
+ * retention_data and suspend in order for proper suspend/resume to work.
  */
 struct samsung_pin_ctrl {
 	const struct samsung_pin_bank_data *pin_banks;

include/linux/soc/samsung/exynos-regs-pmu.h

@@ -42,6 +42,8 @@
 #define EXYNOS_SWRESET				0x0400
 
 #define S5P_WAKEUP_STAT				0x0600
+/* Value for EXYNOS_EINT_WAKEUP_MASK disabling all external wakeup interrupts */
+#define EXYNOS_EINT_WAKEUP_MASK_DISABLED	0xffffffff
 #define EXYNOS_EINT_WAKEUP_MASK			0x0604
 #define S5P_WAKEUP_MASK				0x0608
 #define S5P_WAKEUP_MASK2				0x0614