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/*
* 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;
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 */
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);
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