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 /* 18 * Early Hardware specific Interrupt setup 19 * -Called very early (start_kernel -> setup_arch -> setup_processor) 20 * -Platform Independent (must for any ARC Core) 21 * -Needed for each CPU (hence not foldable into init_IRQ) 22 */ 23 void arc_init_IRQ(void) 24 { 25 unsigned int tmp; 26 27 struct aux_irq_ctrl { 28 #ifdef CONFIG_CPU_BIG_ENDIAN 29 unsigned int res3:18, save_idx_regs:1, res2:1, 30 save_u_to_u:1, save_lp_regs:1, save_blink:1, 31 res:4, save_nr_gpr_pairs:5; 32 #else 33 unsigned int save_nr_gpr_pairs:5, res:4, 34 save_blink:1, save_lp_regs:1, save_u_to_u:1, 35 res2:1, save_idx_regs:1, res3:18; 36 #endif 37 } ictrl; 38 39 *(unsigned int *)&ictrl = 0; 40 41 ictrl.save_nr_gpr_pairs = 6; /* r0 to r11 (r12 saved manually) */ 42 ictrl.save_blink = 1; 43 ictrl.save_lp_regs = 1; /* LP_COUNT, LP_START, LP_END */ 44 ictrl.save_u_to_u = 0; /* user ctxt saved on kernel stack */ 45 ictrl.save_idx_regs = 1; /* JLI, LDI, EI */ 46 47 WRITE_AUX(AUX_IRQ_CTRL, ictrl); 48 49 /* setup status32, don't enable intr yet as kernel doesn't want */ 50 tmp = read_aux_reg(0xa); 51 tmp |= ISA_INIT_STATUS_BITS; 52 tmp &= ~STATUS_IE_MASK; 53 asm volatile("flag %0 \n"::"r"(tmp)); 54 55 /* 56 * ARCv2 core intc provides multiple interrupt priorities (upto 16). 57 * Typical builds though have only two levels (0-high, 1-low) 58 * Linux by default uses lower prio 1 for most irqs, reserving 0 for 59 * NMI style interrupts in future (say perf) 60 * 61 * Read the intc BCR to confirm that Linux default priority is avail 62 * in h/w 63 * 64 * Note: 65 * IRQ_BCR[27..24] contains N-1 (for N priority levels) and prio level 66 * is 0 based. 67 */ 68 tmp = (read_aux_reg(ARC_REG_IRQ_BCR) >> 24 ) & 0xF; 69 if (ARCV2_IRQ_DEF_PRIO > tmp) 70 panic("Linux default irq prio incorrect\n"); 71 } 72 73 static void arcv2_irq_mask(struct irq_data *data) 74 { 75 write_aux_reg(AUX_IRQ_SELECT, data->irq); 76 write_aux_reg(AUX_IRQ_ENABLE, 0); 77 } 78 79 static void arcv2_irq_unmask(struct irq_data *data) 80 { 81 write_aux_reg(AUX_IRQ_SELECT, data->irq); 82 write_aux_reg(AUX_IRQ_ENABLE, 1); 83 } 84 85 void arcv2_irq_enable(struct irq_data *data) 86 { 87 /* set default priority */ 88 write_aux_reg(AUX_IRQ_SELECT, data->irq); 89 write_aux_reg(AUX_IRQ_PRIORITY, ARCV2_IRQ_DEF_PRIO); 90 91 /* 92 * hw auto enables (linux unmask) all by default 93 * So no need to do IRQ_ENABLE here 94 * XXX: However OSCI LAN need it 95 */ 96 write_aux_reg(AUX_IRQ_ENABLE, 1); 97 } 98 99 static struct irq_chip arcv2_irq_chip = { 100 .name = "ARCv2 core Intc", 101 .irq_mask = arcv2_irq_mask, 102 .irq_unmask = arcv2_irq_unmask, 103 .irq_enable = arcv2_irq_enable 104 }; 105 106 static int arcv2_irq_map(struct irq_domain *d, unsigned int irq, 107 irq_hw_number_t hw) 108 { 109 /* 110 * core intc IRQs [16, 23]: 111 * Statically assigned always private-per-core (Timers, WDT, IPI, PCT) 112 */ 113 if (hw < 24) { 114 /* 115 * A subsequent request_percpu_irq() fails if percpu_devid is 116 * not set. That in turns sets NOAUTOEN, meaning each core needs 117 * to call enable_percpu_irq() 118 */ 119 irq_set_percpu_devid(irq); 120 irq_set_chip_and_handler(irq, &arcv2_irq_chip, handle_percpu_irq); 121 } else { 122 irq_set_chip_and_handler(irq, &arcv2_irq_chip, handle_level_irq); 123 } 124 125 return 0; 126 } 127 128 static const struct irq_domain_ops arcv2_irq_ops = { 129 .xlate = irq_domain_xlate_onecell, 130 .map = arcv2_irq_map, 131 }; 132 133 static struct irq_domain *root_domain; 134 135 static int __init 136 init_onchip_IRQ(struct device_node *intc, struct device_node *parent) 137 { 138 if (parent) 139 panic("DeviceTree incore intc not a root irq controller\n"); 140 141 root_domain = irq_domain_add_legacy(intc, NR_CPU_IRQS, 0, 0, 142 &arcv2_irq_ops, NULL); 143 144 if (!root_domain) 145 panic("root irq domain not avail\n"); 146 147 /* with this we don't need to export root_domain */ 148 irq_set_default_host(root_domain); 149 150 return 0; 151 } 152 153 IRQCHIP_DECLARE(arc_intc, "snps,archs-intc", init_onchip_IRQ); 154