diff options
Diffstat (limited to 'arch/arc/kernel/intc-arcv2.c')
| -rw-r--r-- | arch/arc/kernel/intc-arcv2.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/arch/arc/kernel/intc-arcv2.c b/arch/arc/kernel/intc-arcv2.c new file mode 100644 index 000000000..cf18b3e5a --- /dev/null +++ b/arch/arc/kernel/intc-arcv2.c @@ -0,0 +1,195 @@ +/* + * Copyright (C) 2014 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/irqdomain.h> +#include <linux/irqchip.h> +#include <asm/irq.h> + +#define NR_EXCEPTIONS 16 + +struct bcr_irq_arcv2 { +#ifdef CONFIG_CPU_BIG_ENDIAN + unsigned int pad:3, firq:1, prio:4, exts:8, irqs:8, ver:8; +#else + unsigned int ver:8, irqs:8, exts:8, prio:4, firq:1, pad:3; +#endif +}; + +/* + * Early Hardware specific Interrupt setup + * -Called very early (start_kernel -> setup_arch -> setup_processor) + * -Platform Independent (must for any ARC Core) + * -Needed for each CPU (hence not foldable into init_IRQ) + */ +void arc_init_IRQ(void) +{ + unsigned int tmp, irq_prio, i; + struct bcr_irq_arcv2 irq_bcr; + + struct aux_irq_ctrl { +#ifdef CONFIG_CPU_BIG_ENDIAN + unsigned int res3:18, save_idx_regs:1, res2:1, + save_u_to_u:1, save_lp_regs:1, save_blink:1, + res:4, save_nr_gpr_pairs:5; +#else + unsigned int save_nr_gpr_pairs:5, res:4, + save_blink:1, save_lp_regs:1, save_u_to_u:1, + res2:1, save_idx_regs:1, res3:18; +#endif + } ictrl; + + *(unsigned int *)&ictrl = 0; + +#ifndef CONFIG_ARC_IRQ_NO_AUTOSAVE + ictrl.save_nr_gpr_pairs = 6; /* r0 to r11 (r12 saved manually) */ + ictrl.save_blink = 1; + ictrl.save_lp_regs = 1; /* LP_COUNT, LP_START, LP_END */ + ictrl.save_u_to_u = 0; /* user ctxt saved on kernel stack */ + ictrl.save_idx_regs = 1; /* JLI, LDI, EI */ +#endif + + WRITE_AUX(AUX_IRQ_CTRL, ictrl); + + /* + * ARCv2 core intc provides multiple interrupt priorities (upto 16). + * Typical builds though have only two levels (0-high, 1-low) + * Linux by default uses lower prio 1 for most irqs, reserving 0 for + * NMI style interrupts in future (say perf) + */ + + READ_BCR(ARC_REG_IRQ_BCR, irq_bcr); + + irq_prio = irq_bcr.prio; /* Encoded as N-1 for N levels */ + pr_info("archs-intc\t: %d priority levels (default %d)%s\n", + irq_prio + 1, ARCV2_IRQ_DEF_PRIO, + irq_bcr.firq ? " FIRQ (not used)":""); + + /* + * Set a default priority for all available interrupts to prevent + * switching of register banks if Fast IRQ and multiple register banks + * are supported by CPU. + * Also disable private-per-core IRQ lines so faulty external HW won't + * trigger interrupt that kernel is not ready to handle. + */ + for (i = NR_EXCEPTIONS; i < irq_bcr.irqs + NR_EXCEPTIONS; i++) { + write_aux_reg(AUX_IRQ_SELECT, i); + write_aux_reg(AUX_IRQ_PRIORITY, ARCV2_IRQ_DEF_PRIO); + + /* + * Only mask cpu private IRQs here. + * "common" interrupts are masked at IDU, otherwise it would + * need to be unmasked at each cpu, with IPIs + */ + if (i < FIRST_EXT_IRQ) + write_aux_reg(AUX_IRQ_ENABLE, 0); + } + + /* setup status32, don't enable intr yet as kernel doesn't want */ + tmp = read_aux_reg(ARC_REG_STATUS32); + tmp |= STATUS_AD_MASK | (ARCV2_IRQ_DEF_PRIO << 1); + tmp &= ~STATUS_IE_MASK; + asm volatile("kflag %0 \n"::"r"(tmp)); +} + +static void arcv2_irq_mask(struct irq_data *data) +{ + write_aux_reg(AUX_IRQ_SELECT, data->hwirq); + write_aux_reg(AUX_IRQ_ENABLE, 0); +} + +static void arcv2_irq_unmask(struct irq_data *data) +{ + write_aux_reg(AUX_IRQ_SELECT, data->hwirq); + write_aux_reg(AUX_IRQ_ENABLE, 1); +} + +void arcv2_irq_enable(struct irq_data *data) +{ + /* set default priority */ + write_aux_reg(AUX_IRQ_SELECT, data->hwirq); + write_aux_reg(AUX_IRQ_PRIORITY, ARCV2_IRQ_DEF_PRIO); + + /* + * hw auto enables (linux unmask) all by default + * So no need to do IRQ_ENABLE here + * XXX: However OSCI LAN need it + */ + write_aux_reg(AUX_IRQ_ENABLE, 1); +} + +static struct irq_chip arcv2_irq_chip = { + .name = "ARCv2 core Intc", + .irq_mask = arcv2_irq_mask, + .irq_unmask = arcv2_irq_unmask, + .irq_enable = arcv2_irq_enable +}; + +static int arcv2_irq_map(struct irq_domain *d, unsigned int irq, + irq_hw_number_t hw) +{ + /* + * core intc IRQs [16, 23]: + * Statically assigned always private-per-core (Timers, WDT, IPI, PCT) + */ + if (hw < FIRST_EXT_IRQ) { + /* + * A subsequent request_percpu_irq() fails if percpu_devid is + * not set. That in turns sets NOAUTOEN, meaning each core needs + * to call enable_percpu_irq() + */ + irq_set_percpu_devid(irq); + irq_set_chip_and_handler(irq, &arcv2_irq_chip, handle_percpu_irq); + } else { + irq_set_chip_and_handler(irq, &arcv2_irq_chip, handle_level_irq); + } + + return 0; +} + +static const struct irq_domain_ops arcv2_irq_ops = { + .xlate = irq_domain_xlate_onecell, + .map = arcv2_irq_map, +}; + + +static int __init +init_onchip_IRQ(struct device_node *intc, struct device_node *parent) +{ + struct irq_domain *root_domain; + struct bcr_irq_arcv2 irq_bcr; + unsigned int nr_cpu_irqs; + + READ_BCR(ARC_REG_IRQ_BCR, irq_bcr); + nr_cpu_irqs = irq_bcr.irqs + NR_EXCEPTIONS; + + if (parent) + panic("DeviceTree incore intc not a root irq controller\n"); + + root_domain = irq_domain_add_linear(intc, nr_cpu_irqs, &arcv2_irq_ops, NULL); + if (!root_domain) + panic("root irq domain not avail\n"); + + /* + * Needed for primary domain lookup to succeed + * This is a primary irqchip, and can never have a parent + */ + irq_set_default_host(root_domain); + +#ifdef CONFIG_SMP + irq_create_mapping(root_domain, IPI_IRQ); +#endif + irq_create_mapping(root_domain, SOFTIRQ_IRQ); + + return 0; +} + +IRQCHIP_DECLARE(arc_intc, "snps,archs-intc", init_onchip_IRQ); |