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![Jonathan Neuschäfer](/assets/img/avatar_default.png)
The WPCM450 AIC ("Advanced Interrupt Controller") is the interrupt controller found in the Nuvoton WPCM450 SoC and other Winbond/Nuvoton SoCs. The list of registers if based on the AMI vendor kernel and the Nuvoton W90N745 datasheet. Although the hardware supports other interrupt modes, the driver only supports high-level interrupts at the moment, because other modes could not be tested so far. Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210406120921.2484986-7-j.neuschaefer@gmx.net
161 lines
4.3 KiB
C
161 lines
4.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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// Copyright 2021 Jonathan Neuschäfer
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#include <linux/irqchip.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/printk.h>
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#include <asm/exception.h>
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#define AIC_SCR(x) ((x)*4) /* Source control registers */
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#define AIC_GEN 0x84 /* Interrupt group enable control register */
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#define AIC_GRSR 0x88 /* Interrupt group raw status register */
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#define AIC_IRSR 0x100 /* Interrupt raw status register */
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#define AIC_IASR 0x104 /* Interrupt active status register */
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#define AIC_ISR 0x108 /* Interrupt status register */
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#define AIC_IPER 0x10c /* Interrupt priority encoding register */
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#define AIC_ISNR 0x110 /* Interrupt source number register */
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#define AIC_IMR 0x114 /* Interrupt mask register */
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#define AIC_OISR 0x118 /* Output interrupt status register */
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#define AIC_MECR 0x120 /* Mask enable command register */
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#define AIC_MDCR 0x124 /* Mask disable command register */
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#define AIC_SSCR 0x128 /* Source set command register */
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#define AIC_SCCR 0x12c /* Source clear command register */
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#define AIC_EOSCR 0x130 /* End of service command register */
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#define AIC_SCR_SRCTYPE_LOW_LEVEL (0 << 6)
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#define AIC_SCR_SRCTYPE_HIGH_LEVEL (1 << 6)
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#define AIC_SCR_SRCTYPE_NEG_EDGE (2 << 6)
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#define AIC_SCR_SRCTYPE_POS_EDGE (3 << 6)
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#define AIC_SCR_PRIORITY(x) (x)
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#define AIC_SCR_PRIORITY_MASK 0x7
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#define AIC_NUM_IRQS 32
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struct wpcm450_aic {
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void __iomem *regs;
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struct irq_domain *domain;
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};
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static struct wpcm450_aic *aic;
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static void wpcm450_aic_init_hw(void)
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{
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int i;
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/* Disable (mask) all interrupts */
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writel(0xffffffff, aic->regs + AIC_MDCR);
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/*
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* Make sure the interrupt controller is ready to serve new interrupts.
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* Reading from IPER indicates that the nIRQ signal may be deasserted,
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* and writing to EOSCR indicates that interrupt handling has finished.
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*/
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readl(aic->regs + AIC_IPER);
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writel(0, aic->regs + AIC_EOSCR);
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/* Initialize trigger mode and priority of each interrupt source */
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for (i = 0; i < AIC_NUM_IRQS; i++)
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writel(AIC_SCR_SRCTYPE_HIGH_LEVEL | AIC_SCR_PRIORITY(7),
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aic->regs + AIC_SCR(i));
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}
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static void __exception_irq_entry wpcm450_aic_handle_irq(struct pt_regs *regs)
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{
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int hwirq;
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/* Determine the interrupt source */
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/* Read IPER to signal that nIRQ can be de-asserted */
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hwirq = readl(aic->regs + AIC_IPER) / 4;
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handle_domain_irq(aic->domain, hwirq, regs);
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}
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static void wpcm450_aic_eoi(struct irq_data *d)
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{
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/* Signal end-of-service */
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writel(0, aic->regs + AIC_EOSCR);
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}
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static void wpcm450_aic_mask(struct irq_data *d)
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{
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unsigned int mask = BIT(d->hwirq);
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/* Disable (mask) the interrupt */
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writel(mask, aic->regs + AIC_MDCR);
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}
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static void wpcm450_aic_unmask(struct irq_data *d)
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{
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unsigned int mask = BIT(d->hwirq);
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/* Enable (unmask) the interrupt */
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writel(mask, aic->regs + AIC_MECR);
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}
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static int wpcm450_aic_set_type(struct irq_data *d, unsigned int flow_type)
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{
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/*
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* The hardware supports high/low level, as well as rising/falling edge
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* modes, and the DT binding accommodates for that, but as long as
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* other modes than high level mode are not used and can't be tested,
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* they are rejected in this driver.
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*/
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if ((flow_type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_HIGH)
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return -EINVAL;
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return 0;
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}
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static struct irq_chip wpcm450_aic_chip = {
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.name = "wpcm450-aic",
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.irq_eoi = wpcm450_aic_eoi,
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.irq_mask = wpcm450_aic_mask,
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.irq_unmask = wpcm450_aic_unmask,
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.irq_set_type = wpcm450_aic_set_type,
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};
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static int wpcm450_aic_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hwirq)
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{
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if (hwirq >= AIC_NUM_IRQS)
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return -EPERM;
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irq_set_chip_and_handler(irq, &wpcm450_aic_chip, handle_fasteoi_irq);
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irq_set_chip_data(irq, aic);
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irq_set_probe(irq);
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return 0;
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}
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static const struct irq_domain_ops wpcm450_aic_ops = {
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.map = wpcm450_aic_map,
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.xlate = irq_domain_xlate_twocell,
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};
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static int __init wpcm450_aic_of_init(struct device_node *node,
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struct device_node *parent)
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{
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if (parent)
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return -EINVAL;
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aic = kzalloc(sizeof(*aic), GFP_KERNEL);
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if (!aic)
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return -ENOMEM;
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aic->regs = of_iomap(node, 0);
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if (!aic->regs) {
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pr_err("Failed to map WPCM450 AIC registers\n");
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return -ENOMEM;
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}
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wpcm450_aic_init_hw();
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set_handle_irq(wpcm450_aic_handle_irq);
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aic->domain = irq_domain_add_linear(node, AIC_NUM_IRQS, &wpcm450_aic_ops, aic);
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return 0;
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}
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IRQCHIP_DECLARE(wpcm450_aic, "nuvoton,wpcm450-aic", wpcm450_aic_of_init);
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