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-rw-r--r--drivers/irqchip/irq-wpcm450-aic.c162
1 files changed, 162 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-wpcm450-aic.c b/drivers/irqchip/irq-wpcm450-aic.c
new file mode 100644
index 000000000..91df62a64
--- /dev/null
+++ b/drivers/irqchip/irq-wpcm450-aic.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright 2021 Jonathan Neuschäfer
+
+#include <linux/irqchip.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/printk.h>
+
+#include <asm/exception.h>
+
+#define AIC_SCR(x) ((x)*4) /* Source control registers */
+#define AIC_GEN 0x84 /* Interrupt group enable control register */
+#define AIC_GRSR 0x88 /* Interrupt group raw status register */
+#define AIC_IRSR 0x100 /* Interrupt raw status register */
+#define AIC_IASR 0x104 /* Interrupt active status register */
+#define AIC_ISR 0x108 /* Interrupt status register */
+#define AIC_IPER 0x10c /* Interrupt priority encoding register */
+#define AIC_ISNR 0x110 /* Interrupt source number register */
+#define AIC_IMR 0x114 /* Interrupt mask register */
+#define AIC_OISR 0x118 /* Output interrupt status register */
+#define AIC_MECR 0x120 /* Mask enable command register */
+#define AIC_MDCR 0x124 /* Mask disable command register */
+#define AIC_SSCR 0x128 /* Source set command register */
+#define AIC_SCCR 0x12c /* Source clear command register */
+#define AIC_EOSCR 0x130 /* End of service command register */
+
+#define AIC_SCR_SRCTYPE_LOW_LEVEL (0 << 6)
+#define AIC_SCR_SRCTYPE_HIGH_LEVEL (1 << 6)
+#define AIC_SCR_SRCTYPE_NEG_EDGE (2 << 6)
+#define AIC_SCR_SRCTYPE_POS_EDGE (3 << 6)
+#define AIC_SCR_PRIORITY(x) (x)
+#define AIC_SCR_PRIORITY_MASK 0x7
+
+#define AIC_NUM_IRQS 32
+
+struct wpcm450_aic {
+ void __iomem *regs;
+ struct irq_domain *domain;
+};
+
+static struct wpcm450_aic *aic;
+
+static void wpcm450_aic_init_hw(void)
+{
+ int i;
+
+ /* Disable (mask) all interrupts */
+ writel(0xffffffff, aic->regs + AIC_MDCR);
+
+ /*
+ * Make sure the interrupt controller is ready to serve new interrupts.
+ * Reading from IPER indicates that the nIRQ signal may be deasserted,
+ * and writing to EOSCR indicates that interrupt handling has finished.
+ */
+ readl(aic->regs + AIC_IPER);
+ writel(0, aic->regs + AIC_EOSCR);
+
+ /* Initialize trigger mode and priority of each interrupt source */
+ for (i = 0; i < AIC_NUM_IRQS; i++)
+ writel(AIC_SCR_SRCTYPE_HIGH_LEVEL | AIC_SCR_PRIORITY(7),
+ aic->regs + AIC_SCR(i));
+}
+
+static void __exception_irq_entry wpcm450_aic_handle_irq(struct pt_regs *regs)
+{
+ int hwirq;
+
+ /* Determine the interrupt source */
+ /* Read IPER to signal that nIRQ can be de-asserted */
+ hwirq = readl(aic->regs + AIC_IPER) / 4;
+
+ generic_handle_domain_irq(aic->domain, hwirq);
+}
+
+static void wpcm450_aic_eoi(struct irq_data *d)
+{
+ /* Signal end-of-service */
+ writel(0, aic->regs + AIC_EOSCR);
+}
+
+static void wpcm450_aic_mask(struct irq_data *d)
+{
+ unsigned int mask = BIT(d->hwirq);
+
+ /* Disable (mask) the interrupt */
+ writel(mask, aic->regs + AIC_MDCR);
+}
+
+static void wpcm450_aic_unmask(struct irq_data *d)
+{
+ unsigned int mask = BIT(d->hwirq);
+
+ /* Enable (unmask) the interrupt */
+ writel(mask, aic->regs + AIC_MECR);
+}
+
+static int wpcm450_aic_set_type(struct irq_data *d, unsigned int flow_type)
+{
+ /*
+ * The hardware supports high/low level, as well as rising/falling edge
+ * modes, and the DT binding accommodates for that, but as long as
+ * other modes than high level mode are not used and can't be tested,
+ * they are rejected in this driver.
+ */
+ if ((flow_type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_HIGH)
+ return -EINVAL;
+
+ return 0;
+}
+
+static struct irq_chip wpcm450_aic_chip = {
+ .name = "wpcm450-aic",
+ .irq_eoi = wpcm450_aic_eoi,
+ .irq_mask = wpcm450_aic_mask,
+ .irq_unmask = wpcm450_aic_unmask,
+ .irq_set_type = wpcm450_aic_set_type,
+};
+
+static int wpcm450_aic_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hwirq)
+{
+ if (hwirq >= AIC_NUM_IRQS)
+ return -EPERM;
+
+ irq_set_chip_and_handler(irq, &wpcm450_aic_chip, handle_fasteoi_irq);
+ irq_set_chip_data(irq, aic);
+ irq_set_probe(irq);
+
+ return 0;
+}
+
+static const struct irq_domain_ops wpcm450_aic_ops = {
+ .map = wpcm450_aic_map,
+ .xlate = irq_domain_xlate_twocell,
+};
+
+static int __init wpcm450_aic_of_init(struct device_node *node,
+ struct device_node *parent)
+{
+ if (parent)
+ return -EINVAL;
+
+ aic = kzalloc(sizeof(*aic), GFP_KERNEL);
+ if (!aic)
+ return -ENOMEM;
+
+ aic->regs = of_iomap(node, 0);
+ if (!aic->regs) {
+ pr_err("Failed to map WPCM450 AIC registers\n");
+ kfree(aic);
+ return -ENOMEM;
+ }
+
+ wpcm450_aic_init_hw();
+
+ set_handle_irq(wpcm450_aic_handle_irq);
+
+ aic->domain = irq_domain_add_linear(node, AIC_NUM_IRQS, &wpcm450_aic_ops, aic);
+
+ return 0;
+}
+
+IRQCHIP_DECLARE(wpcm450_aic, "nuvoton,wpcm450-aic", wpcm450_aic_of_init);