irqchip/irq-pruss-intc: Implement irq_{get, set}_irqchip_state ops

This implements the irq_get_irqchip_state and irq_set_irqchip_state
callbacks for the TI PRUSS INTC driver. The set callback can be used
by drivers to "kick" a PRU by injecting a PRU system event.
Co-developed-by: Suman Anna <s-anna@ti.com>
Co-developed-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
Reviewed-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>

drivers/irqchip/irq-pruss-intc.c

@@ -12,6 +12,7 @@
  * Copyright (C) 2019 David Lechner <david@lechnology.com>
  */
 
+#include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/irqchip/chained_irq.h>
 #include <linux/irqdomain.h>
@@ -323,6 +324,43 @@ static void pruss_intc_irq_relres(struct irq_data *data)
 	module_put(THIS_MODULE);
 }
 
+static int pruss_intc_irq_get_irqchip_state(struct irq_data *data,
+					    enum irqchip_irq_state which,
+					    bool *state)
+{
+	struct pruss_intc *intc = irq_data_get_irq_chip_data(data);
+	u32 reg, mask, srsr;
+
+	if (which != IRQCHIP_STATE_PENDING)
+		return -EINVAL;
+
+	reg = PRU_INTC_SRSR(data->hwirq / 32);
+	mask = BIT(data->hwirq % 32);
+
+	srsr = pruss_intc_read_reg(intc, reg);
+
+	*state = !!(srsr & mask);
+
+	return 0;
+}
+
+static int pruss_intc_irq_set_irqchip_state(struct irq_data *data,
+					    enum irqchip_irq_state which,
+					    bool state)
+{
+	struct pruss_intc *intc = irq_data_get_irq_chip_data(data);
+
+	if (which != IRQCHIP_STATE_PENDING)
+		return -EINVAL;
+
+	if (state)
+		pruss_intc_write_reg(intc, PRU_INTC_SISR, data->hwirq);
+	else
+		pruss_intc_write_reg(intc, PRU_INTC_SICR, data->hwirq);
+
+	return 0;
+}
+
 static struct irq_chip pruss_irqchip = {
 	.name			= "pruss-intc",
 	.irq_ack		= pruss_intc_irq_ack,
@@ -330,6 +368,8 @@ static struct irq_chip pruss_irqchip = {
 	.irq_unmask		= pruss_intc_irq_unmask,
 	.irq_request_resources	= pruss_intc_irq_reqres,
 	.irq_release_resources	= pruss_intc_irq_relres,
+	.irq_get_irqchip_state	= pruss_intc_irq_get_irqchip_state,
+	.irq_set_irqchip_state	= pruss_intc_irq_set_irqchip_state,
 };
 
 static int pruss_intc_validate_mapping(struct pruss_intc *intc, int event,