arch/mips/mips-boards/atlas/atlas_int.c

   1 /*
   2  * Copyright (C) 1999, 2000, 2006  MIPS Technologies, Inc.
   3  *      All rights reserved.
   4  *      Authors: Carsten Langgaard <carstenl@mips.com>
   5  *               Maciej W. Rozycki <macro@mips.com>
   6  *
   7  * ########################################################################
   8  *
   9  *  This program is free software; you can distribute it and/or modify it
  10  *  under the terms of the GNU General Public License (Version 2) as
  11  *  published by the Free Software Foundation.
  12  *
  13  *  This program is distributed in the hope it will be useful, but WITHOUT
  14  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16  *  for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License along
  19  *  with this program; if not, write to the Free Software Foundation, Inc.,
  20  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  21  *
  22  * ########################################################################
  23  *
  24  * Routines for generic manipulation of the interrupts found on the MIPS
  25  * Atlas board.
  26  *
  27  */
  28 #include <linux/compiler.h>
  29 #include <linux/init.h>
  30 #include <linux/irq.h>
  31 #include <linux/sched.h>
  32 #include <linux/slab.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/kernel_stat.h>
  35 #include <linux/kernel.h>
  36
  37 #include <asm/gdb-stub.h>
  38 #include <asm/io.h>
  39 #include <asm/irq_cpu.h>
  40 #include <asm/msc01_ic.h>
  41
  42 #include <asm/mips-boards/atlas.h>
  43 #include <asm/mips-boards/atlasint.h>
  44 #include <asm/mips-boards/generic.h>
  45
  46 static struct atlas_ictrl_regs *atlas_hw0_icregs;
  47
  48 #if 0
  49 #define DEBUG_INT(x...) printk(x)
  50 #else
  51 #define DEBUG_INT(x...)
  52 #endif
  53
  54 void disable_atlas_irq(unsigned int irq_nr)
  55 {
  56         atlas_hw0_icregs->intrsten = 1 << (irq_nr - ATLAS_INT_BASE);
  57         iob();
  58 }
  59
  60 void enable_atlas_irq(unsigned int irq_nr)
  61 {
  62         atlas_hw0_icregs->intseten = 1 << (irq_nr - ATLAS_INT_BASE);
  63         iob();
  64 }
  65
  66 static void end_atlas_irq(unsigned int irq)
  67 {
  68         if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
  69                 enable_atlas_irq(irq);
  70 }
  71
  72 static struct irq_chip atlas_irq_type = {
  73         .name = "Atlas",
  74         .ack = disable_atlas_irq,
  75         .mask = disable_atlas_irq,
  76         .mask_ack = disable_atlas_irq,
  77         .unmask = enable_atlas_irq,
  78         .eoi = enable_atlas_irq,
  79         .end = end_atlas_irq,
  80 };
  81
  82 static inline int ls1bit32(unsigned int x)
  83 {
  84         int b = 31, s;
  85
  86         s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
  87         s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
  88         s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
  89         s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
  90         s =  1; if (x <<  1 == 0) s = 0; b -= s;
  91
  92         return b;
  93 }
  94
  95 static inline void atlas_hw0_irqdispatch(void)
  96 {
  97         unsigned long int_status;
  98         int irq;
  99
 100         int_status = atlas_hw0_icregs->intstatus;
 101
 102         /* if int_status == 0, then the interrupt has already been cleared */
 103         if (unlikely(int_status == 0))
 104                 return;
 105
 106         irq = ATLAS_INT_BASE + ls1bit32(int_status);
 107
 108         DEBUG_INT("atlas_hw0_irqdispatch: irq=%d\n", irq);
 109
 110         do_IRQ(irq);
 111 }
 112
 113 static inline int clz(unsigned long x)
 114 {
 115         __asm__ (
 116         "       .set    push                                    \n"
 117         "       .set    mips32                                  \n"
 118         "       clz     %0, %1                                  \n"
 119         "       .set    pop                                     \n"
 120         : "=r" (x)
 121         : "r" (x));
 122
 123         return x;
 124 }
 125
 126 /*
 127  * Version of ffs that only looks at bits 12..15.
 128  */
 129 static inline unsigned int irq_ffs(unsigned int pending)
 130 {
 131 #if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
 132         return -clz(pending) + 31 - CAUSEB_IP;
 133 #else
 134         unsigned int a0 = 7;
 135         unsigned int t0;
 136
 137         t0 = s0 & 0xf000;
 138         t0 = t0 < 1;
 139         t0 = t0 << 2;
 140         a0 = a0 - t0;
 141         s0 = s0 << t0;
 142
 143         t0 = s0 & 0xc000;
 144         t0 = t0 < 1;
 145         t0 = t0 << 1;
 146         a0 = a0 - t0;
 147         s0 = s0 << t0;
 148
 149         t0 = s0 & 0x8000;
 150         t0 = t0 < 1;
 151         //t0 = t0 << 2;
 152         a0 = a0 - t0;
 153         //s0 = s0 << t0;
 154
 155         return a0;
 156 #endif
 157 }
 158
 159 /*
 160  * IRQs on the Atlas board look basically like (all external interrupt
 161  * sources are combined together on hardware interrupt 0 (MIPS IRQ 2)):
 162  *
 163  *      MIPS IRQ        Source
 164  *      --------        ------
 165  *             0        Software 0 (reschedule IPI on MT)
 166  *             1        Software 1 (remote call IPI on MT)
 167  *             2        Combined Atlas hardware interrupt (hw0)
 168  *             3        Hardware (ignored)
 169  *             4        Hardware (ignored)
 170  *             5        Hardware (ignored)
 171  *             6        Hardware (ignored)
 172  *             7        R4k timer (what we use)
 173  *
 174  * We handle the IRQ according to _our_ priority which is:
 175  *
 176  * Highest ----     R4k Timer
 177  * Lowest  ----     Software 0
 178  *
 179  * then we just return, if multiple IRQs are pending then we will just take
 180  * another exception, big deal.
 181  */
 182 asmlinkage void plat_irq_dispatch(void)
 183 {
 184         unsigned int pending = read_c0_cause() & read_c0_status() & ST0_IM;
 185         int irq;
 186
 187         irq = irq_ffs(pending);
 188
 189         if (irq == MIPSCPU_INT_ATLAS)
 190                 atlas_hw0_irqdispatch();
 191         else if (irq >= 0)
 192                 do_IRQ(MIPS_CPU_IRQ_BASE + irq);
 193         else
 194                 spurious_interrupt();
 195 }
 196
 197 static inline void init_atlas_irqs (int base)
 198 {
 199         int i;
 200
 201         atlas_hw0_icregs = (struct atlas_ictrl_regs *)
 202                            ioremap(ATLAS_ICTRL_REGS_BASE,
 203                                    sizeof(struct atlas_ictrl_regs *));
 204
 205         /*
 206          * Mask out all interrupt by writing "1" to all bit position in
 207          * the interrupt reset reg.
 208          */
 209         atlas_hw0_icregs->intrsten = 0xffffffff;
 210
 211         for (i = ATLAS_INT_BASE; i <= ATLAS_INT_END; i++)
 212                 set_irq_chip_and_handler(i, &atlas_irq_type, handle_level_irq);
 213 }
 214
 215 static struct irqaction atlasirq = {
 216         .handler = no_action,
 217         .name = "Atlas cascade"
 218 };
 219
 220 msc_irqmap_t __initdata msc_irqmap[] = {
 221         {MSC01C_INT_TMR,                MSC01_IRQ_EDGE, 0},
 222         {MSC01C_INT_PCI,                MSC01_IRQ_LEVEL, 0},
 223 };
 224 int __initdata msc_nr_irqs = ARRAY_SIZE(msc_irqmap);
 225
 226 msc_irqmap_t __initdata msc_eicirqmap[] = {
 227         {MSC01E_INT_SW0,                MSC01_IRQ_LEVEL, 0},
 228         {MSC01E_INT_SW1,                MSC01_IRQ_LEVEL, 0},
 229         {MSC01E_INT_ATLAS,              MSC01_IRQ_LEVEL, 0},
 230         {MSC01E_INT_TMR,                MSC01_IRQ_EDGE, 0},
 231         {MSC01E_INT_PCI,                MSC01_IRQ_LEVEL, 0},
 232         {MSC01E_INT_PERFCTR,            MSC01_IRQ_LEVEL, 0},
 233         {MSC01E_INT_CPUCTR,             MSC01_IRQ_LEVEL, 0}
 234 };
 235 int __initdata msc_nr_eicirqs = ARRAY_SIZE(msc_eicirqmap);
 236
 237 void __init arch_init_irq(void)
 238 {
 239         init_atlas_irqs(ATLAS_INT_BASE);
 240
 241         if (!cpu_has_veic)
 242                 mips_cpu_irq_init();
 243
 244         switch(mips_revision_corid) {
 245         case MIPS_REVISION_CORID_CORE_MSC:
 246         case MIPS_REVISION_CORID_CORE_FPGA2:
 247         case MIPS_REVISION_CORID_CORE_FPGA3:
 248         case MIPS_REVISION_CORID_CORE_24K:
 249         case MIPS_REVISION_CORID_CORE_EMUL_MSC:
 250                 if (cpu_has_veic)
 251                         init_msc_irqs (MSC01E_INT_BASE, MSC01E_INT_BASE,
 252                                        msc_eicirqmap, msc_nr_eicirqs);
 253                 else
 254                         init_msc_irqs (MSC01E_INT_BASE, MSC01C_INT_BASE,
 255                                        msc_irqmap, msc_nr_irqs);
 256         }
 257
 258         if (cpu_has_veic) {
 259                 set_vi_handler (MSC01E_INT_ATLAS, atlas_hw0_irqdispatch);
 260                 setup_irq (MSC01E_INT_BASE + MSC01E_INT_ATLAS, &atlasirq);
 261         } else if (cpu_has_vint) {
 262                 set_vi_handler (MIPSCPU_INT_ATLAS, atlas_hw0_irqdispatch);
 263 #ifdef CONFIG_MIPS_MT_SMTC
 264                 setup_irq_smtc (MIPS_CPU_IRQ_BASE + MIPSCPU_INT_ATLAS,
 265                                 &atlasirq, (0x100 << MIPSCPU_INT_ATLAS));
 266 #else /* Not SMTC */
 267                 setup_irq(MIPS_CPU_IRQ_BASE + MIPSCPU_INT_ATLAS, &atlasirq);
 268 #endif /* CONFIG_MIPS_MT_SMTC */
 269         } else
 270                 setup_irq(MIPS_CPU_IRQ_BASE + MIPSCPU_INT_ATLAS, &atlasirq);
 271 }