arch/powerpc/platforms/512x/mpc5121_ads_cpld.c

   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_host *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 NO_IRQ;
 101
 102         cpld_irq = ffz(status) + offset;
 103
 104         return irq_linear_revmap(cpld_pic_host, cpld_irq);
 105 }
 106
 107 static void
 108 cpld_pic_cascade(unsigned int irq, struct irq_desc *desc)
 109 {
 110         irq = cpld_pic_get_irq(0, PCI_IGNORE, &cpld_regs->pci_status,
 111                 &cpld_regs->pci_mask);
 112         if (irq != NO_IRQ) {
 113                 generic_handle_irq(irq);
 114                 return;
 115         }
 116
 117         irq = cpld_pic_get_irq(8, MISC_IGNORE, &cpld_regs->misc_status,
 118                 &cpld_regs->misc_mask);
 119         if (irq != NO_IRQ) {
 120                 generic_handle_irq(irq);
 121                 return;
 122         }
 123 }
 124
 125 static int
 126 cpld_pic_host_match(struct irq_host *h, struct device_node *node)
 127 {
 128         return cpld_pic_node == node;
 129 }
 130
 131 static int
 132 cpld_pic_host_map(struct irq_host *h, unsigned int virq,
 133                              irq_hw_number_t hw)
 134 {
 135         irq_set_status_flags(virq, IRQ_LEVEL);
 136         irq_set_chip_and_handler(virq, &cpld_pic, handle_level_irq);
 137         return 0;
 138 }
 139
 140 static struct
 141 irq_host_ops cpld_pic_host_ops = {
 142         .match = cpld_pic_host_match,
 143         .map = cpld_pic_host_map,
 144 };
 145
 146 void __init
 147 mpc5121_ads_cpld_map(void)
 148 {
 149         struct device_node *np = NULL;
 150
 151         np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
 152         if (!np) {
 153                 printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
 154                 return;
 155         }
 156
 157         cpld_regs = of_iomap(np, 0);
 158         of_node_put(np);
 159 }
 160
 161 void __init
 162 mpc5121_ads_cpld_pic_init(void)
 163 {
 164         unsigned int cascade_irq;
 165         struct device_node *np = NULL;
 166
 167         pr_debug("cpld_ic_init\n");
 168
 169         np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
 170         if (!np) {
 171                 printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
 172                 return;
 173         }
 174
 175         if (!cpld_regs)
 176                 goto end;
 177
 178         cascade_irq = irq_of_parse_and_map(np, 0);
 179         if (cascade_irq == NO_IRQ)
 180                 goto end;
 181
 182         /*
 183          * statically route touch screen pendown through 1
 184          * and ignore it here
 185          * route all others through our cascade irq
 186          */
 187         out_8(&cpld_regs->route, 0xfd);
 188         out_8(&cpld_regs->pci_mask, 0xff);
 189         /* unmask pci ints in misc mask */
 190         out_8(&cpld_regs->misc_mask, ~(MISC_IGNORE));
 191
 192         cpld_pic_node = of_node_get(np);
 193
 194         cpld_pic_host =
 195             irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, 16, &cpld_pic_host_ops, 16);
 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 }