arch/mips/kernel/smp-mt.c

   1 /*
   2  *  This program is free software; you can distribute it and/or modify it
   3  *  under the terms of the GNU General Public License (Version 2) as
   4  *  published by the Free Software Foundation.
   5  *
   6  *  This program is distributed in the hope it will be useful, but WITHOUT
   7  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   8  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   9  *  for more details.
  10  *
  11  *  You should have received a copy of the GNU General Public License along
  12  *  with this program; if not, write to the Free Software Foundation, Inc.,
  13  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  14  *
  15  * Copyright (C) 2004, 05, 06 MIPS Technologies, Inc.
  16  *    Elizabeth Clarke (beth@mips.com)
  17  *    Ralf Baechle (ralf@linux-mips.org)
  18  * Copyright (C) 2006 Ralf Baechle (ralf@linux-mips.org)
  19  */
  20 #include <linux/kernel.h>
  21 #include <linux/sched.h>
  22 #include <linux/cpumask.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/compiler.h>
  25 #include <linux/smp.h>
  26
  27 #include <linux/atomic.h>
  28 #include <asm/cacheflush.h>
  29 #include <asm/cpu.h>
  30 #include <asm/processor.h>
  31 #include <asm/hardirq.h>
  32 #include <asm/mmu_context.h>
  33 #include <asm/time.h>
  34 #include <asm/mipsregs.h>
  35 #include <asm/mipsmtregs.h>
  36 #include <asm/mips_mt.h>
  37 #include <asm/gic.h>
  38
  39 static void __init smvp_copy_vpe_config(void)
  40 {
  41         write_vpe_c0_status(
  42                 (read_c0_status() & ~(ST0_IM | ST0_IE | ST0_KSU)) | ST0_CU0);
  43
  44         /* set config to be the same as vpe0, particularly kseg0 coherency alg */
  45         write_vpe_c0_config( read_c0_config());
  46
  47         /* make sure there are no software interrupts pending */
  48         write_vpe_c0_cause(0);
  49
  50         /* Propagate Config7 */
  51         write_vpe_c0_config7(read_c0_config7());
  52
  53         write_vpe_c0_count(read_c0_count());
  54 }
  55
  56 static unsigned int __init smvp_vpe_init(unsigned int tc, unsigned int mvpconf0,
  57         unsigned int ncpu)
  58 {
  59         if (tc > ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT))
  60                 return ncpu;
  61
  62         /* Deactivate all but VPE 0 */
  63         if (tc != 0) {
  64                 unsigned long tmp = read_vpe_c0_vpeconf0();
  65
  66                 tmp &= ~VPECONF0_VPA;
  67
  68                 /* master VPE */
  69                 tmp |= VPECONF0_MVP;
  70                 write_vpe_c0_vpeconf0(tmp);
  71
  72                 /* Record this as available CPU */
  73                 set_cpu_possible(tc, true);
  74                 __cpu_number_map[tc]    = ++ncpu;
  75                 __cpu_logical_map[ncpu] = tc;
  76         }
  77
  78         /* Disable multi-threading with TC's */
  79         write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() & ~VPECONTROL_TE);
  80
  81         if (tc != 0)
  82                 smvp_copy_vpe_config();
  83
  84         return ncpu;
  85 }
  86
  87 static void __init smvp_tc_init(unsigned int tc, unsigned int mvpconf0)
  88 {
  89         unsigned long tmp;
  90
  91         if (!tc)
  92                 return;
  93
  94         /* bind a TC to each VPE, May as well put all excess TC's
  95            on the last VPE */
  96         if (tc >= (((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT)+1))
  97                 write_tc_c0_tcbind(read_tc_c0_tcbind() | ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT));
  98         else {
  99                 write_tc_c0_tcbind(read_tc_c0_tcbind() | tc);
 100
 101                 /* and set XTC */
 102                 write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | (tc << VPECONF0_XTC_SHIFT));
 103         }
 104
 105         tmp = read_tc_c0_tcstatus();
 106
 107         /* mark not allocated and not dynamically allocatable */
 108         tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
 109         tmp |= TCSTATUS_IXMT;           /* interrupt exempt */
 110         write_tc_c0_tcstatus(tmp);
 111
 112         write_tc_c0_tchalt(TCHALT_H);
 113 }
 114
 115 static void vsmp_send_ipi_single(int cpu, unsigned int action)
 116 {
 117         int i;
 118         unsigned long flags;
 119         int vpflags;
 120
 121         local_irq_save(flags);
 122
 123         vpflags = dvpe();       /* can't access the other CPU's registers whilst MVPE enabled */
 124
 125         switch (action) {
 126         case SMP_CALL_FUNCTION:
 127                 i = C_SW1;
 128                 break;
 129
 130         case SMP_RESCHEDULE_YOURSELF:
 131         default:
 132                 i = C_SW0;
 133                 break;
 134         }
 135
 136         /* 1:1 mapping of vpe and tc... */
 137         settc(cpu);
 138         write_vpe_c0_cause(read_vpe_c0_cause() | i);
 139         evpe(vpflags);
 140
 141         local_irq_restore(flags);
 142 }
 143
 144 static void vsmp_send_ipi_mask(const struct cpumask *mask, unsigned int action)
 145 {
 146         unsigned int i;
 147
 148         for_each_cpu(i, mask)
 149                 vsmp_send_ipi_single(i, action);
 150 }
 151
 152 static void __cpuinit vsmp_init_secondary(void)
 153 {
 154 #ifdef CONFIG_IRQ_GIC
 155         /* This is Malta specific: IPI,performance and timer interrupts */
 156         if (gic_present)
 157                 change_c0_status(ST0_IM, STATUSF_IP3 | STATUSF_IP4 |
 158                                          STATUSF_IP6 | STATUSF_IP7);
 159         else
 160 #endif
 161                 change_c0_status(ST0_IM, STATUSF_IP0 | STATUSF_IP1 |
 162                                          STATUSF_IP6 | STATUSF_IP7);
 163 }
 164
 165 static void __cpuinit vsmp_smp_finish(void)
 166 {
 167         /* CDFIXME: remove this? */
 168         write_c0_compare(read_c0_count() + (8* mips_hpt_frequency/HZ));
 169
 170 #ifdef CONFIG_MIPS_MT_FPAFF
 171         /* If we have an FPU, enroll ourselves in the FPU-full mask */
 172         if (cpu_has_fpu)
 173                 cpu_set(smp_processor_id(), mt_fpu_cpumask);
 174 #endif /* CONFIG_MIPS_MT_FPAFF */
 175
 176         local_irq_enable();
 177 }
 178
 179 static void vsmp_cpus_done(void)
 180 {
 181 }
 182
 183 /*
 184  * Setup the PC, SP, and GP of a secondary processor and start it
 185  * running!
 186  * smp_bootstrap is the place to resume from
 187  * __KSTK_TOS(idle) is apparently the stack pointer
 188  * (unsigned long)idle->thread_info the gp
 189  * assumes a 1:1 mapping of TC => VPE
 190  */
 191 static void __cpuinit vsmp_boot_secondary(int cpu, struct task_struct *idle)
 192 {
 193         struct thread_info *gp = task_thread_info(idle);
 194         dvpe();
 195         set_c0_mvpcontrol(MVPCONTROL_VPC);
 196
 197         settc(cpu);
 198
 199         /* restart */
 200         write_tc_c0_tcrestart((unsigned long)&smp_bootstrap);
 201
 202         /* enable the tc this vpe/cpu will be running */
 203         write_tc_c0_tcstatus((read_tc_c0_tcstatus() & ~TCSTATUS_IXMT) | TCSTATUS_A);
 204
 205         write_tc_c0_tchalt(0);
 206
 207         /* enable the VPE */
 208         write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | VPECONF0_VPA);
 209
 210         /* stack pointer */
 211         write_tc_gpr_sp( __KSTK_TOS(idle));
 212
 213         /* global pointer */
 214         write_tc_gpr_gp((unsigned long)gp);
 215
 216         flush_icache_range((unsigned long)gp,
 217                            (unsigned long)(gp + sizeof(struct thread_info)));
 218
 219         /* finally out of configuration and into chaos */
 220         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 221
 222         evpe(EVPE_ENABLE);
 223 }
 224
 225 /*
 226  * Common setup before any secondaries are started
 227  * Make sure all CPU's are in a sensible state before we boot any of the
 228  * secondaries
 229  */
 230 static void __init vsmp_smp_setup(void)
 231 {
 232         unsigned int mvpconf0, ntc, tc, ncpu = 0;
 233         unsigned int nvpe;
 234
 235 #ifdef CONFIG_MIPS_MT_FPAFF
 236         /* If we have an FPU, enroll ourselves in the FPU-full mask */
 237         if (cpu_has_fpu)
 238                 cpu_set(0, mt_fpu_cpumask);
 239 #endif /* CONFIG_MIPS_MT_FPAFF */
 240         if (!cpu_has_mipsmt)
 241                 return;
 242
 243         /* disable MT so we can configure */
 244         dvpe();
 245         dmt();
 246
 247         /* Put MVPE's into 'configuration state' */
 248         set_c0_mvpcontrol(MVPCONTROL_VPC);
 249
 250         mvpconf0 = read_c0_mvpconf0();
 251         ntc = (mvpconf0 & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT;
 252
 253         nvpe = ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
 254         smp_num_siblings = nvpe;
 255
 256         /* we'll always have more TC's than VPE's, so loop setting everything
 257            to a sensible state */
 258         for (tc = 0; tc <= ntc; tc++) {
 259                 settc(tc);
 260
 261                 smvp_tc_init(tc, mvpconf0);
 262                 ncpu = smvp_vpe_init(tc, mvpconf0, ncpu);
 263         }
 264
 265         /* Release config state */
 266         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 267
 268         /* We'll wait until starting the secondaries before starting MVPE */
 269
 270         printk(KERN_INFO "Detected %i available secondary CPU(s)\n", ncpu);
 271 }
 272
 273 static void __init vsmp_prepare_cpus(unsigned int max_cpus)
 274 {
 275         mips_mt_set_cpuoptions();
 276 }
 277
 278 struct plat_smp_ops vsmp_smp_ops = {
 279         .send_ipi_single        = vsmp_send_ipi_single,
 280         .send_ipi_mask          = vsmp_send_ipi_mask,
 281         .init_secondary         = vsmp_init_secondary,
 282         .smp_finish             = vsmp_smp_finish,
 283         .cpus_done              = vsmp_cpus_done,
 284         .boot_secondary         = vsmp_boot_secondary,
 285         .smp_setup              = vsmp_smp_setup,
 286         .prepare_cpus           = vsmp_prepare_cpus,
 287 };