1 /* 2 * Copyright (C) 2008 Freescale Semiconductor, Inc. All rights reserved. 3 * 4 * Author: John Rigby, <jrigby@freescale.com> 5 * 6 * Description: 7 * MPC5121ADS CPLD irq handling 8 * 9 * This is free software; you can redistribute it and/or modify it 10 * under the terms of the GNU General Public License as published by 11 * the Free Software Foundation; either version 2 of the License, or 12 * (at your option) any later version. 13 */ 14 15 #undef DEBUG 16 17 #include <linux/kernel.h> 18 #include <linux/interrupt.h> 19 #include <linux/irq.h> 20 #include <linux/io.h> 21 #include <asm/prom.h> 22 23 static struct device_node *cpld_pic_node; 24 static struct irq_domain *cpld_pic_host; 25 26 /* 27 * Bits to ignore in the misc_status register 28 * 0x10 touch screen pendown is hard routed to irq1 29 * 0x02 pci status is read from pci status register 30 */ 31 #define MISC_IGNORE 0x12 32 33 /* 34 * Nothing to ignore in pci status register 35 */ 36 #define PCI_IGNORE 0x00 37 38 struct cpld_pic { 39 u8 pci_mask; 40 u8 pci_status; 41 u8 route; 42 u8 misc_mask; 43 u8 misc_status; 44 u8 misc_control; 45 }; 46 47 static struct cpld_pic __iomem *cpld_regs; 48 49 static void __iomem * 50 irq_to_pic_mask(unsigned int irq) 51 { 52 return irq <= 7 ? &cpld_regs->pci_mask : &cpld_regs->misc_mask; 53 } 54 55 static unsigned int 56 irq_to_pic_bit(unsigned int irq) 57 { 58 return 1 << (irq & 0x7); 59 } 60 61 static void 62 cpld_mask_irq(struct irq_data *d) 63 { 64 unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d); 65 void __iomem *pic_mask = irq_to_pic_mask(cpld_irq); 66 67 out_8(pic_mask, 68 in_8(pic_mask) | irq_to_pic_bit(cpld_irq)); 69 } 70 71 static void 72 cpld_unmask_irq(struct irq_data *d) 73 { 74 unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d); 75 void __iomem *pic_mask = irq_to_pic_mask(cpld_irq); 76 77 out_8(pic_mask, 78 in_8(pic_mask) & ~irq_to_pic_bit(cpld_irq)); 79 } 80 81 static struct irq_chip cpld_pic = { 82 .name = "CPLD PIC", 83 .irq_mask = cpld_mask_irq, 84 .irq_ack = cpld_mask_irq, 85 .irq_unmask = cpld_unmask_irq, 86 }; 87 88 static int 89 cpld_pic_get_irq(int offset, u8 ignore, u8 __iomem *statusp, 90 u8 __iomem *maskp) 91 { 92 int cpld_irq; 93 u8 status = in_8(statusp); 94 u8 mask = in_8(maskp); 95 96 /* ignore don't cares and masked irqs */ 97 status |= (ignore | mask); 98 99 if (status == 0xff) 100 return 0; 101 102 cpld_irq = ffz(status) + offset; 103 104 return irq_linear_revmap(cpld_pic_host, cpld_irq); 105 } 106 107 static void cpld_pic_cascade(struct irq_desc *desc) 108 { 109 unsigned int irq; 110 111 irq = cpld_pic_get_irq(0, PCI_IGNORE, &cpld_regs->pci_status, 112 &cpld_regs->pci_mask); 113 if (irq) { 114 generic_handle_irq(irq); 115 return; 116 } 117 118 irq = cpld_pic_get_irq(8, MISC_IGNORE, &cpld_regs->misc_status, 119 &cpld_regs->misc_mask); 120 if (irq) { 121 generic_handle_irq(irq); 122 return; 123 } 124 } 125 126 static int 127 cpld_pic_host_match(struct irq_domain *h, struct device_node *node, 128 enum irq_domain_bus_token bus_token) 129 { 130 return cpld_pic_node == node; 131 } 132 133 static int 134 cpld_pic_host_map(struct irq_domain *h, unsigned int virq, 135 irq_hw_number_t hw) 136 { 137 irq_set_status_flags(virq, IRQ_LEVEL); 138 irq_set_chip_and_handler(virq, &cpld_pic, handle_level_irq); 139 return 0; 140 } 141 142 static const struct irq_domain_ops cpld_pic_host_ops = { 143 .match = cpld_pic_host_match, 144 .map = cpld_pic_host_map, 145 }; 146 147 void __init 148 mpc5121_ads_cpld_map(void) 149 { 150 struct device_node *np = NULL; 151 152 np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic"); 153 if (!np) { 154 printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n"); 155 return; 156 } 157 158 cpld_regs = of_iomap(np, 0); 159 of_node_put(np); 160 } 161 162 void __init 163 mpc5121_ads_cpld_pic_init(void) 164 { 165 unsigned int cascade_irq; 166 struct device_node *np = NULL; 167 168 pr_debug("cpld_ic_init\n"); 169 170 np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic"); 171 if (!np) { 172 printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n"); 173 return; 174 } 175 176 if (!cpld_regs) 177 goto end; 178 179 cascade_irq = irq_of_parse_and_map(np, 0); 180 if (!cascade_irq) 181 goto end; 182 183 /* 184 * statically route touch screen pendown through 1 185 * and ignore it here 186 * route all others through our cascade irq 187 */ 188 out_8(&cpld_regs->route, 0xfd); 189 out_8(&cpld_regs->pci_mask, 0xff); 190 /* unmask pci ints in misc mask */ 191 out_8(&cpld_regs->misc_mask, ~(MISC_IGNORE)); 192 193 cpld_pic_node = of_node_get(np); 194 195 cpld_pic_host = irq_domain_add_linear(np, 16, &cpld_pic_host_ops, NULL); 196 if (!cpld_pic_host) { 197 printk(KERN_ERR "CPLD PIC: failed to allocate irq host!\n"); 198 goto end; 199 } 200 201 irq_set_chained_handler(cascade_irq, cpld_pic_cascade); 202 end: 203 of_node_put(np); 204 } 205