arch/arc/kernel/intc-arcv2.c

   1 /*
   2  * Copyright (C) 2014 Synopsys, Inc. (www.synopsys.com)
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  */
   9
  10 #include <linux/interrupt.h>
  11 #include <linux/module.h>
  12 #include <linux/of.h>
  13 #include <linux/irqdomain.h>
  14 #include <linux/irqchip.h>
  15 #include <asm/irq.h>
  16
  17 static int irq_prio;
  18
  19 /*
  20  * Early Hardware specific Interrupt setup
  21  * -Called very early (start_kernel -> setup_arch -> setup_processor)
  22  * -Platform Independent (must for any ARC Core)
  23  * -Needed for each CPU (hence not foldable into init_IRQ)
  24  */
  25 void arc_init_IRQ(void)
  26 {
  27         unsigned int tmp;
  28
  29         struct irq_build {
  30 #ifdef CONFIG_CPU_BIG_ENDIAN
  31                 unsigned int pad:3, firq:1, prio:4, exts:8, irqs:8, ver:8;
  32 #else
  33                 unsigned int ver:8, irqs:8, exts:8, prio:4, firq:1, pad:3;
  34 #endif
  35         } irq_bcr;
  36
  37         struct aux_irq_ctrl {
  38 #ifdef CONFIG_CPU_BIG_ENDIAN
  39                 unsigned int res3:18, save_idx_regs:1, res2:1,
  40                              save_u_to_u:1, save_lp_regs:1, save_blink:1,
  41                              res:4, save_nr_gpr_pairs:5;
  42 #else
  43                 unsigned int save_nr_gpr_pairs:5, res:4,
  44                              save_blink:1, save_lp_regs:1, save_u_to_u:1,
  45                              res2:1, save_idx_regs:1, res3:18;
  46 #endif
  47         } ictrl;
  48
  49         *(unsigned int *)&ictrl = 0;
  50
  51         ictrl.save_nr_gpr_pairs = 6;    /* r0 to r11 (r12 saved manually) */
  52         ictrl.save_blink = 1;
  53         ictrl.save_lp_regs = 1;         /* LP_COUNT, LP_START, LP_END */
  54         ictrl.save_u_to_u = 0;          /* user ctxt saved on kernel stack */
  55         ictrl.save_idx_regs = 1;        /* JLI, LDI, EI */
  56
  57         WRITE_AUX(AUX_IRQ_CTRL, ictrl);
  58
  59         /*
  60          * ARCv2 core intc provides multiple interrupt priorities (upto 16).
  61          * Typical builds though have only two levels (0-high, 1-low)
  62          * Linux by default uses lower prio 1 for most irqs, reserving 0 for
  63          * NMI style interrupts in future (say perf)
  64          */
  65
  66         READ_BCR(ARC_REG_IRQ_BCR, irq_bcr);
  67
  68         irq_prio = irq_bcr.prio;        /* Encoded as N-1 for N levels */
  69         pr_info("archs-intc\t: %d priority levels (default %d)%s\n",
  70                 irq_prio + 1, irq_prio,
  71                 irq_bcr.firq ? " FIRQ (not used)":"");
  72
  73         /* setup status32, don't enable intr yet as kernel doesn't want */
  74         tmp = read_aux_reg(0xa);
  75         tmp |= STATUS_AD_MASK | (irq_prio << 1);
  76         tmp &= ~STATUS_IE_MASK;
  77         asm volatile("flag %0   \n"::"r"(tmp));
  78 }
  79
  80 static void arcv2_irq_mask(struct irq_data *data)
  81 {
  82         write_aux_reg(AUX_IRQ_SELECT, data->irq);
  83         write_aux_reg(AUX_IRQ_ENABLE, 0);
  84 }
  85
  86 static void arcv2_irq_unmask(struct irq_data *data)
  87 {
  88         write_aux_reg(AUX_IRQ_SELECT, data->irq);
  89         write_aux_reg(AUX_IRQ_ENABLE, 1);
  90 }
  91
  92 void arcv2_irq_enable(struct irq_data *data)
  93 {
  94         /* set default priority */
  95         write_aux_reg(AUX_IRQ_SELECT, data->irq);
  96         write_aux_reg(AUX_IRQ_PRIORITY, irq_prio);
  97
  98         /*
  99          * hw auto enables (linux unmask) all by default
 100          * So no need to do IRQ_ENABLE here
 101          * XXX: However OSCI LAN need it
 102          */
 103         write_aux_reg(AUX_IRQ_ENABLE, 1);
 104 }
 105
 106 static struct irq_chip arcv2_irq_chip = {
 107         .name           = "ARCv2 core Intc",
 108         .irq_mask       = arcv2_irq_mask,
 109         .irq_unmask     = arcv2_irq_unmask,
 110         .irq_enable     = arcv2_irq_enable
 111 };
 112
 113 static int arcv2_irq_map(struct irq_domain *d, unsigned int irq,
 114                          irq_hw_number_t hw)
 115 {
 116         /*
 117          * core intc IRQs [16, 23]:
 118          * Statically assigned always private-per-core (Timers, WDT, IPI, PCT)
 119          */
 120         if (hw < 24) {
 121                 /*
 122                  * A subsequent request_percpu_irq() fails if percpu_devid is
 123                  * not set. That in turns sets NOAUTOEN, meaning each core needs
 124                  * to call enable_percpu_irq()
 125                  */
 126                 irq_set_percpu_devid(irq);
 127                 irq_set_chip_and_handler(irq, &arcv2_irq_chip, handle_percpu_irq);
 128         } else {
 129                 irq_set_chip_and_handler(irq, &arcv2_irq_chip, handle_level_irq);
 130         }
 131
 132         return 0;
 133 }
 134
 135 static const struct irq_domain_ops arcv2_irq_ops = {
 136         .xlate = irq_domain_xlate_onecell,
 137         .map = arcv2_irq_map,
 138 };
 139
 140 static struct irq_domain *root_domain;
 141
 142 static int __init
 143 init_onchip_IRQ(struct device_node *intc, struct device_node *parent)
 144 {
 145         if (parent)
 146                 panic("DeviceTree incore intc not a root irq controller\n");
 147
 148         root_domain = irq_domain_add_legacy(intc, NR_CPU_IRQS, 0, 0,
 149                                             &arcv2_irq_ops, NULL);
 150
 151         if (!root_domain)
 152                 panic("root irq domain not avail\n");
 153
 154         /* with this we don't need to export root_domain */
 155         irq_set_default_host(root_domain);
 156
 157         return 0;
 158 }
 159
 160 IRQCHIP_DECLARE(arc_intc, "snps,archs-intc", init_onchip_IRQ);