diff options
Diffstat (limited to 'drivers/irqchip/irq-wpcm450-aic.c')
| -rw-r--r-- | drivers/irqchip/irq-wpcm450-aic.c | 162 |
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); |