arch/powerpc/platforms/86xx/gef_pic.c

   1 /*
   2  * Interrupt handling for GE FPGA based PIC
   3  *
   4  * Author: Martyn Welch <martyn.welch@ge.com>
   5  *
   6  * 2008 (c) GE Intelligent Platforms Embedded Systems, Inc.
   7  *
   8  * This file is licensed under the terms of the GNU General Public License
   9  * version 2.  This program is licensed "as is" without any warranty of any
  10  * kind, whether express or implied.
  11  */
  12
  13 #include <linux/stddef.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/irq.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/spinlock.h>
  19
  20 #include <asm/byteorder.h>
  21 #include <asm/io.h>
  22 #include <asm/prom.h>
  23 #include <asm/irq.h>
  24
  25 #include "gef_pic.h"
  26
  27 #define DEBUG
  28 #undef DEBUG
  29
  30 #ifdef DEBUG
  31 #define DBG(fmt...) do { printk(KERN_DEBUG "gef_pic: " fmt); } while (0)
  32 #else
  33 #define DBG(fmt...) do { } while (0)
  34 #endif
  35
  36 #define GEF_PIC_NUM_IRQS        32
  37
  38 /* Interrupt Controller Interface Registers */
  39 #define GEF_PIC_INTR_STATUS     0x0000
  40
  41 #define GEF_PIC_INTR_MASK(cpu)  (0x0010 + (0x4 * cpu))
  42 #define GEF_PIC_CPU0_INTR_MASK  GEF_PIC_INTR_MASK(0)
  43 #define GEF_PIC_CPU1_INTR_MASK  GEF_PIC_INTR_MASK(1)
  44
  45 #define GEF_PIC_MCP_MASK(cpu)   (0x0018 + (0x4 * cpu))
  46 #define GEF_PIC_CPU0_MCP_MASK   GEF_PIC_MCP_MASK(0)
  47 #define GEF_PIC_CPU1_MCP_MASK   GEF_PIC_MCP_MASK(1)
  48
  49 #define gef_irq_to_hw(virq)    ((unsigned int)irq_map[virq].hwirq)
  50
  51
  52 static DEFINE_RAW_SPINLOCK(gef_pic_lock);
  53
  54 static void __iomem *gef_pic_irq_reg_base;
  55 static struct irq_host *gef_pic_irq_host;
  56 static int gef_pic_cascade_irq;
  57
  58 /*
  59  * Interrupt Controller Handling
  60  *
  61  * The interrupt controller handles interrupts for most on board interrupts,
  62  * apart from PCI interrupts. For example on SBC610:
  63  *
  64  * 17:31 RO Reserved
  65  * 16    RO PCI Express Doorbell 3 Status
  66  * 15    RO PCI Express Doorbell 2 Status
  67  * 14    RO PCI Express Doorbell 1 Status
  68  * 13    RO PCI Express Doorbell 0 Status
  69  * 12    RO Real Time Clock Interrupt Status
  70  * 11    RO Temperature Interrupt Status
  71  * 10    RO Temperature Critical Interrupt Status
  72  * 9     RO Ethernet PHY1 Interrupt Status
  73  * 8     RO Ethernet PHY3 Interrupt Status
  74  * 7     RO PEX8548 Interrupt Status
  75  * 6     RO Reserved
  76  * 5     RO Watchdog 0 Interrupt Status
  77  * 4     RO Watchdog 1 Interrupt Status
  78  * 3     RO AXIS Message FIFO A Interrupt Status
  79  * 2     RO AXIS Message FIFO B Interrupt Status
  80  * 1     RO AXIS Message FIFO C Interrupt Status
  81  * 0     RO AXIS Message FIFO D Interrupt Status
  82  *
  83  * Interrupts can be forwarded to one of two output lines. Nothing
  84  * clever is done, so if the masks are incorrectly set, a single input
  85  * interrupt could generate interrupts on both output lines!
  86  *
  87  * The dual lines are there to allow the chained interrupts to be easily
  88  * passed into two different cores. We currently do not use this functionality
  89  * in this driver.
  90  *
  91  * Controller can also be configured to generate Machine checks (MCP), again on
  92  * two lines, to be attached to two different cores. It is suggested that these
  93  * should be masked out.
  94  */
  95
  96 void gef_pic_cascade(unsigned int irq, struct irq_desc *desc)
  97 {
  98         unsigned int cascade_irq;
  99
 100         /*
 101          * See if we actually have an interrupt, call generic handling code if
 102          * we do.
 103          */
 104         cascade_irq = gef_pic_get_irq();
 105
 106         if (cascade_irq != NO_IRQ)
 107                 generic_handle_irq(cascade_irq);
 108
 109         desc->chip->eoi(irq);
 110
 111 }
 112
 113 static void gef_pic_mask(unsigned int virq)
 114 {
 115         unsigned long flags;
 116         unsigned int hwirq;
 117         u32 mask;
 118
 119         hwirq = gef_irq_to_hw(virq);
 120
 121         raw_spin_lock_irqsave(&gef_pic_lock, flags);
 122         mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0));
 123         mask &= ~(1 << hwirq);
 124         out_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0), mask);
 125         raw_spin_unlock_irqrestore(&gef_pic_lock, flags);
 126 }
 127
 128 static void gef_pic_mask_ack(unsigned int virq)
 129 {
 130         /* Don't think we actually have to do anything to ack an interrupt,
 131          * we just need to clear down the devices interrupt and it will go away
 132          */
 133         gef_pic_mask(virq);
 134 }
 135
 136 static void gef_pic_unmask(unsigned int virq)
 137 {
 138         unsigned long flags;
 139         unsigned int hwirq;
 140         u32 mask;
 141
 142         hwirq = gef_irq_to_hw(virq);
 143
 144         raw_spin_lock_irqsave(&gef_pic_lock, flags);
 145         mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0));
 146         mask |= (1 << hwirq);
 147         out_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0), mask);
 148         raw_spin_unlock_irqrestore(&gef_pic_lock, flags);
 149 }
 150
 151 static struct irq_chip gef_pic_chip = {
 152         .name           = "gefp",
 153         .mask           = gef_pic_mask,
 154         .mask_ack       = gef_pic_mask_ack,
 155         .unmask         = gef_pic_unmask,
 156 };
 157
 158
 159 /* When an interrupt is being configured, this call allows some flexibilty
 160  * in deciding which irq_chip structure is used
 161  */
 162 static int gef_pic_host_map(struct irq_host *h, unsigned int virq,
 163                           irq_hw_number_t hwirq)
 164 {
 165         /* All interrupts are LEVEL sensitive */
 166         irq_to_desc(virq)->status |= IRQ_LEVEL;
 167         set_irq_chip_and_handler(virq, &gef_pic_chip, handle_level_irq);
 168
 169         return 0;
 170 }
 171
 172 static int gef_pic_host_xlate(struct irq_host *h, struct device_node *ct,
 173                             const u32 *intspec, unsigned int intsize,
 174                             irq_hw_number_t *out_hwirq, unsigned int *out_flags)
 175 {
 176
 177         *out_hwirq = intspec[0];
 178         if (intsize > 1)
 179                 *out_flags = intspec[1];
 180         else
 181                 *out_flags = IRQ_TYPE_LEVEL_HIGH;
 182
 183         return 0;
 184 }
 185
 186 static struct irq_host_ops gef_pic_host_ops = {
 187         .map    = gef_pic_host_map,
 188         .xlate  = gef_pic_host_xlate,
 189 };
 190
 191
 192 /*
 193  * Initialisation of PIC, this should be called in BSP
 194  */
 195 void __init gef_pic_init(struct device_node *np)
 196 {
 197         unsigned long flags;
 198
 199         /* Map the devices registers into memory */
 200         gef_pic_irq_reg_base = of_iomap(np, 0);
 201
 202         raw_spin_lock_irqsave(&gef_pic_lock, flags);
 203
 204         /* Initialise everything as masked. */
 205         out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU0_INTR_MASK, 0);
 206         out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU1_INTR_MASK, 0);
 207
 208         out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU0_MCP_MASK, 0);
 209         out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU1_MCP_MASK, 0);
 210
 211         raw_spin_unlock_irqrestore(&gef_pic_lock, flags);
 212
 213         /* Map controller */
 214         gef_pic_cascade_irq = irq_of_parse_and_map(np, 0);
 215         if (gef_pic_cascade_irq == NO_IRQ) {
 216                 printk(KERN_ERR "SBC610: failed to map cascade interrupt");
 217                 return;
 218         }
 219
 220         /* Setup an irq_host structure */
 221         gef_pic_irq_host = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR,
 222                                           GEF_PIC_NUM_IRQS,
 223                                           &gef_pic_host_ops, NO_IRQ);
 224         if (gef_pic_irq_host == NULL)
 225                 return;
 226
 227         /* Chain with parent controller */
 228         set_irq_chained_handler(gef_pic_cascade_irq, gef_pic_cascade);
 229 }
 230
 231 /*
 232  * This is called when we receive an interrupt with apparently comes from this
 233  * chip - check, returning the highest interrupt generated or return NO_IRQ
 234  */
 235 unsigned int gef_pic_get_irq(void)
 236 {
 237         u32 cause, mask, active;
 238         unsigned int virq = NO_IRQ;
 239         int hwirq;
 240
 241         cause = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_STATUS);
 242
 243         mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0));
 244
 245         active = cause & mask;
 246
 247         if (active) {
 248                 for (hwirq = GEF_PIC_NUM_IRQS - 1; hwirq > -1; hwirq--) {
 249                         if (active & (0x1 << hwirq))
 250                                 break;
 251                 }
 252                 virq = irq_linear_revmap(gef_pic_irq_host,
 253                         (irq_hw_number_t)hwirq);
 254         }
 255
 256         return virq;
 257 }
 258