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
  38 static void __init smvp_copy_vpe_config(void)
  39 {
  40         write_vpe_c0_status(
  41                 (read_c0_status() & ~(ST0_IM | ST0_IE | ST0_KSU)) | ST0_CU0);
  42
  43         /* set config to be the same as vpe0, particularly kseg0 coherency alg */
  44         write_vpe_c0_config( read_c0_config());
  45
  46         /* make sure there are no software interrupts pending */
  47         write_vpe_c0_cause(0);
  48
  49         /* Propagate Config7 */
  50         write_vpe_c0_config7(read_c0_config7());
  51
  52         write_vpe_c0_count(read_c0_count());
  53 }
  54
  55 static unsigned int __init smvp_vpe_init(unsigned int tc, unsigned int mvpconf0,
  56         unsigned int ncpu)
  57 {
  58         if (tc > ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT))
  59                 return ncpu;
  60
  61         /* Deactivate all but VPE 0 */
  62         if (tc != 0) {
  63                 unsigned long tmp = read_vpe_c0_vpeconf0();
  64
  65                 tmp &= ~VPECONF0_VPA;
  66
  67                 /* master VPE */
  68                 tmp |= VPECONF0_MVP;
  69                 write_vpe_c0_vpeconf0(tmp);
  70
  71                 /* Record this as available CPU */
  72                 set_cpu_possible(tc, true);
  73                 __cpu_number_map[tc]    = ++ncpu;
  74                 __cpu_logical_map[ncpu] = tc;
  75         }
  76
  77         /* Disable multi-threading with TC's */
  78         write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() & ~VPECONTROL_TE);
  79
  80         if (tc != 0)
  81                 smvp_copy_vpe_config();
  82
  83         return ncpu;
  84 }
  85
  86 static void __init smvp_tc_init(unsigned int tc, unsigned int mvpconf0)
  87 {
  88         unsigned long tmp;
  89
  90         if (!tc)
  91                 return;
  92
  93         /* bind a TC to each VPE, May as well put all excess TC's
  94            on the last VPE */
  95         if (tc >= (((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT)+1))
  96                 write_tc_c0_tcbind(read_tc_c0_tcbind() | ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT));
  97         else {
  98                 write_tc_c0_tcbind(read_tc_c0_tcbind() | tc);
  99
 100                 /* and set XTC */
 101                 write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | (tc << VPECONF0_XTC_SHIFT));
 102         }
 103
 104         tmp = read_tc_c0_tcstatus();
 105
 106         /* mark not allocated and not dynamically allocatable */
 107         tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
 108         tmp |= TCSTATUS_IXMT;           /* interrupt exempt */
 109         write_tc_c0_tcstatus(tmp);
 110
 111         write_tc_c0_tchalt(TCHALT_H);
 112 }
 113
 114 static void vsmp_send_ipi_single(int cpu, unsigned int action)
 115 {
 116         int i;
 117         unsigned long flags;
 118         int vpflags;
 119
 120         local_irq_save(flags);
 121
 122         vpflags = dvpe();       /* can't access the other CPU's registers whilst MVPE enabled */
 123
 124         switch (action) {
 125         case SMP_CALL_FUNCTION:
 126                 i = C_SW1;
 127                 break;
 128
 129         case SMP_RESCHEDULE_YOURSELF:
 130         default:
 131                 i = C_SW0;
 132                 break;
 133         }
 134
 135         /* 1:1 mapping of vpe and tc... */
 136         settc(cpu);
 137         write_vpe_c0_cause(read_vpe_c0_cause() | i);
 138         evpe(vpflags);
 139
 140         local_irq_restore(flags);
 141 }
 142
 143 static void vsmp_send_ipi_mask(const struct cpumask *mask, unsigned int action)
 144 {
 145         unsigned int i;
 146
 147         for_each_cpu(i, mask)
 148                 vsmp_send_ipi_single(i, action);
 149 }
 150
 151 static void __cpuinit vsmp_init_secondary(void)
 152 {
 153         extern int gic_present;
 154
 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                 change_c0_status(ST0_IM, STATUSF_IP0 | STATUSF_IP1 |
 161                                          STATUSF_IP6 | STATUSF_IP7);
 162 }
 163
 164 static void __cpuinit vsmp_smp_finish(void)
 165 {
 166         /* CDFIXME: remove this? */
 167         write_c0_compare(read_c0_count() + (8* mips_hpt_frequency/HZ));
 168
 169 #ifdef CONFIG_MIPS_MT_FPAFF
 170         /* If we have an FPU, enroll ourselves in the FPU-full mask */
 171         if (cpu_has_fpu)
 172                 cpu_set(smp_processor_id(), mt_fpu_cpumask);
 173 #endif /* CONFIG_MIPS_MT_FPAFF */
 174
 175         local_irq_enable();
 176 }
 177
 178 static void vsmp_cpus_done(void)
 179 {
 180 }
 181
 182 /*
 183  * Setup the PC, SP, and GP of a secondary processor and start it
 184  * running!
 185  * smp_bootstrap is the place to resume from
 186  * __KSTK_TOS(idle) is apparently the stack pointer
 187  * (unsigned long)idle->thread_info the gp
 188  * assumes a 1:1 mapping of TC => VPE
 189  */
 190 static void __cpuinit vsmp_boot_secondary(int cpu, struct task_struct *idle)
 191 {
 192         struct thread_info *gp = task_thread_info(idle);
 193         dvpe();
 194         set_c0_mvpcontrol(MVPCONTROL_VPC);
 195
 196         settc(cpu);
 197
 198         /* restart */
 199         write_tc_c0_tcrestart((unsigned long)&smp_bootstrap);
 200
 201         /* enable the tc this vpe/cpu will be running */
 202         write_tc_c0_tcstatus((read_tc_c0_tcstatus() & ~TCSTATUS_IXMT) | TCSTATUS_A);
 203
 204         write_tc_c0_tchalt(0);
 205
 206         /* enable the VPE */
 207         write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | VPECONF0_VPA);
 208
 209         /* stack pointer */
 210         write_tc_gpr_sp( __KSTK_TOS(idle));
 211
 212         /* global pointer */
 213         write_tc_gpr_gp((unsigned long)gp);
 214
 215         flush_icache_range((unsigned long)gp,
 216                            (unsigned long)(gp + sizeof(struct thread_info)));
 217
 218         /* finally out of configuration and into chaos */
 219         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 220
 221         evpe(EVPE_ENABLE);
 222 }
 223
 224 /*
 225  * Common setup before any secondaries are started
 226  * Make sure all CPU's are in a sensible state before we boot any of the
 227  * secondaries
 228  */
 229 static void __init vsmp_smp_setup(void)
 230 {
 231         unsigned int mvpconf0, ntc, tc, ncpu = 0;
 232         unsigned int nvpe;
 233
 234 #ifdef CONFIG_MIPS_MT_FPAFF
 235         /* If we have an FPU, enroll ourselves in the FPU-full mask */
 236         if (cpu_has_fpu)
 237                 cpu_set(0, mt_fpu_cpumask);
 238 #endif /* CONFIG_MIPS_MT_FPAFF */
 239         if (!cpu_has_mipsmt)
 240                 return;
 241
 242         /* disable MT so we can configure */
 243         dvpe();
 244         dmt();
 245
 246         /* Put MVPE's into 'configuration state' */
 247         set_c0_mvpcontrol(MVPCONTROL_VPC);
 248
 249         mvpconf0 = read_c0_mvpconf0();
 250         ntc = (mvpconf0 & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT;
 251
 252         nvpe = ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
 253         smp_num_siblings = nvpe;
 254
 255         /* we'll always have more TC's than VPE's, so loop setting everything
 256            to a sensible state */
 257         for (tc = 0; tc <= ntc; tc++) {
 258                 settc(tc);
 259
 260                 smvp_tc_init(tc, mvpconf0);
 261                 ncpu = smvp_vpe_init(tc, mvpconf0, ncpu);
 262         }
 263
 264         /* Release config state */
 265         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 266
 267         /* We'll wait until starting the secondaries before starting MVPE */
 268
 269         printk(KERN_INFO "Detected %i available secondary CPU(s)\n", ncpu);
 270 }
 271
 272 static void __init vsmp_prepare_cpus(unsigned int max_cpus)
 273 {
 274         mips_mt_set_cpuoptions();
 275 }
 276
 277 struct plat_smp_ops vsmp_smp_ops = {
 278         .send_ipi_single        = vsmp_send_ipi_single,
 279         .send_ipi_mask          = vsmp_send_ipi_mask,
 280         .init_secondary         = vsmp_init_secondary,
 281         .smp_finish             = vsmp_smp_finish,
 282         .cpus_done              = vsmp_cpus_done,
 283         .boot_secondary         = vsmp_boot_secondary,
 284         .smp_setup              = vsmp_smp_setup,
 285         .prepare_cpus           = vsmp_prepare_cpus,
 286 };