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   1 /*
   2  * BPA Internal Interrupt Controller
   3  *
   4  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
   5  *
   6  * Author: Arnd Bergmann <arndb@de.ibm.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2, or (at your option)
  11  * any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  */
  22
  23 #include <linux/config.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/irq.h>
  26 #include <linux/percpu.h>
  27 #include <linux/types.h>
  28
  29 #include <asm/io.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/prom.h>
  32 #include <asm/ptrace.h>
  33
  34 #include "bpa_iic.h"
  35
  36 struct iic_pending_bits {
  37         u32 data;
  38         u8 flags;
  39         u8 class;
  40         u8 source;
  41         u8 prio;
  42 };
  43
  44 enum iic_pending_flags {
  45         IIC_VALID = 0x80,
  46         IIC_IPI   = 0x40,
  47 };
  48
  49 struct iic_regs {
  50         struct iic_pending_bits pending;
  51         struct iic_pending_bits pending_destr;
  52         u64 generate;
  53         u64 prio;
  54 };
  55
  56 struct iic {
  57         struct iic_regs __iomem *regs;
  58 };
  59
  60 static DEFINE_PER_CPU(struct iic, iic);
  61
  62 void iic_local_enable(void)
  63 {
  64         out_be64(&__get_cpu_var(iic).regs->prio, 0xff);
  65 }
  66
  67 void iic_local_disable(void)
  68 {
  69         out_be64(&__get_cpu_var(iic).regs->prio, 0x0);
  70 }
  71
  72 static unsigned int iic_startup(unsigned int irq)
  73 {
  74         return 0;
  75 }
  76
  77 static void iic_enable(unsigned int irq)
  78 {
  79         iic_local_enable();
  80 }
  81
  82 static void iic_disable(unsigned int irq)
  83 {
  84 }
  85
  86 static void iic_end(unsigned int irq)
  87 {
  88         iic_local_enable();
  89 }
  90
  91 static struct hw_interrupt_type iic_pic = {
  92         .typename = " BPA-IIC  ",
  93         .startup = iic_startup,
  94         .enable = iic_enable,
  95         .disable = iic_disable,
  96         .end = iic_end,
  97 };
  98
  99 static int iic_external_get_irq(struct iic_pending_bits pending)
 100 {
 101         int irq;
 102         unsigned char node, unit;
 103
 104         node = pending.source >> 4;
 105         unit = pending.source & 0xf;
 106         irq = -1;
 107
 108         /*
 109          * This mapping is specific to the Broadband
 110          * Engine. We might need to get the numbers
 111          * from the device tree to support future CPUs.
 112          */
 113         switch (unit) {
 114         case 0x00:
 115         case 0x0b:
 116                 /*
 117                  * One of these units can be connected
 118                  * to an external interrupt controller.
 119                  */
 120                 if (pending.prio > 0x3f ||
 121                     pending.class != 2)
 122                         break;
 123                 irq = IIC_EXT_OFFSET
 124                         + spider_get_irq(pending.prio + node * IIC_NODE_STRIDE)
 125                         + node * IIC_NODE_STRIDE;
 126                 break;
 127         case 0x01 ... 0x04:
 128         case 0x07 ... 0x0a:
 129                 /*
 130                  * These units are connected to the SPEs
 131                  */
 132                 if (pending.class > 2)
 133                         break;
 134                 irq = IIC_SPE_OFFSET
 135                         + pending.class * IIC_CLASS_STRIDE
 136                         + node * IIC_NODE_STRIDE
 137                         + unit;
 138                 break;
 139         }
 140         if (irq == -1)
 141                 printk(KERN_WARNING "Unexpected interrupt class %02x, "
 142                         "source %02x, prio %02x, cpu %02x\n", pending.class,
 143                         pending.source, pending.prio, smp_processor_id());
 144         return irq;
 145 }
 146
 147 /* Get an IRQ number from the pending state register of the IIC */
 148 int iic_get_irq(struct pt_regs *regs)
 149 {
 150         struct iic *iic;
 151         int irq;
 152         struct iic_pending_bits pending;
 153
 154         iic = &__get_cpu_var(iic);
 155         *(unsigned long *) &pending =
 156                 in_be64((unsigned long __iomem *) &iic->regs->pending_destr);
 157
 158         irq = -1;
 159         if (pending.flags & IIC_VALID) {
 160                 if (pending.flags & IIC_IPI) {
 161                         irq = IIC_IPI_OFFSET + (pending.prio >> 4);
 162 /*
 163                         if (irq > 0x80)
 164                                 printk(KERN_WARNING "Unexpected IPI prio %02x"
 165                                         "on CPU %02x\n", pending.prio,
 166                                                         smp_processor_id());
 167 */
 168                 } else {
 169                         irq = iic_external_get_irq(pending);
 170                 }
 171         }
 172         return irq;
 173 }
 174
 175 static struct iic_regs __iomem *find_iic(int cpu)
 176 {
 177         struct device_node *np;
 178         int nodeid = cpu / 2;
 179         unsigned long regs;
 180         struct iic_regs __iomem *iic_regs;
 181
 182         for (np = of_find_node_by_type(NULL, "cpu");
 183              np;
 184              np = of_find_node_by_type(np, "cpu")) {
 185                 if (nodeid == *(int *)get_property(np, "node-id", NULL))
 186                         break;
 187         }
 188
 189         if (!np) {
 190                 printk(KERN_WARNING "IIC: CPU %d not found\n", cpu);
 191                 iic_regs = NULL;
 192         } else {
 193                 regs = *(long *)get_property(np, "iic", NULL);
 194
 195                 /* hack until we have decided on the devtree info */
 196                 regs += 0x400;
 197                 if (cpu & 1)
 198                         regs += 0x20;
 199
 200                 printk(KERN_DEBUG "IIC for CPU %d at %lx\n", cpu, regs);
 201                 iic_regs = __ioremap(regs, sizeof(struct iic_regs),
 202                                                  _PAGE_NO_CACHE);
 203         }
 204         return iic_regs;
 205 }
 206
 207 #ifdef CONFIG_SMP
 208
 209 /* Use the highest interrupt priorities for IPI */
 210 static inline int iic_ipi_to_irq(int ipi)
 211 {
 212         return IIC_IPI_OFFSET + IIC_NUM_IPIS - 1 - ipi;
 213 }
 214
 215 static inline int iic_irq_to_ipi(int irq)
 216 {
 217         return IIC_NUM_IPIS - 1 - (irq - IIC_IPI_OFFSET);
 218 }
 219
 220 void iic_setup_cpu(void)
 221 {
 222         out_be64(&__get_cpu_var(iic).regs->prio, 0xff);
 223 }
 224
 225 void iic_cause_IPI(int cpu, int mesg)
 226 {
 227         out_be64(&per_cpu(iic, cpu).regs->generate, (IIC_NUM_IPIS - 1 - mesg) << 4);
 228 }
 229
 230 static irqreturn_t iic_ipi_action(int irq, void *dev_id, struct pt_regs *regs)
 231 {
 232         smp_message_recv(iic_irq_to_ipi(irq), regs);
 233         return IRQ_HANDLED;
 234 }
 235
 236 static void iic_request_ipi(int ipi, const char *name)
 237 {
 238         int irq;
 239
 240         irq = iic_ipi_to_irq(ipi);
 241         /* IPIs are marked SA_INTERRUPT as they must run with irqs
 242          * disabled */
 243         get_irq_desc(irq)->handler = &iic_pic;
 244         get_irq_desc(irq)->status |= IRQ_PER_CPU;
 245         request_irq(irq, iic_ipi_action, SA_INTERRUPT, name, NULL);
 246 }
 247
 248 void iic_request_IPIs(void)
 249 {
 250         iic_request_ipi(PPC_MSG_CALL_FUNCTION, "IPI-call");
 251         iic_request_ipi(PPC_MSG_RESCHEDULE, "IPI-resched");
 252 #ifdef CONFIG_DEBUGGER
 253         iic_request_ipi(PPC_MSG_DEBUGGER_BREAK, "IPI-debug");
 254 #endif /* CONFIG_DEBUGGER */
 255 }
 256 #endif /* CONFIG_SMP */
 257
 258 static void iic_setup_spe_handlers(void)
 259 {
 260         int be, isrc;
 261
 262         /* Assume two threads per BE are present */
 263         for (be=0; be < num_present_cpus() / 2; be++) {
 264                 for (isrc = 0; isrc < IIC_CLASS_STRIDE * 3; isrc++) {
 265                         int irq = IIC_NODE_STRIDE * be + IIC_SPE_OFFSET + isrc;
 266                         get_irq_desc(irq)->handler = &iic_pic;
 267                 }
 268         }
 269 }
 270
 271 void iic_init_IRQ(void)
 272 {
 273         int cpu, irq_offset;
 274         struct iic *iic;
 275
 276         irq_offset = 0;
 277         for_each_cpu(cpu) {
 278                 iic = &per_cpu(iic, cpu);
 279                 iic->regs = find_iic(cpu);
 280                 if (iic->regs)
 281                         out_be64(&iic->regs->prio, 0xff);
 282         }
 283         iic_setup_spe_handlers();
 284 }