arch/mips/kernel/smp-mt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  * Copyright (C) 2004, 05, 06 MIPS Technologies, Inc.
   5  *    Elizabeth Clarke (beth@mips.com)
   6  *    Ralf Baechle (ralf@linux-mips.org)
   7  * Copyright (C) 2006 Ralf Baechle (ralf@linux-mips.org)
   8  */
   9 #include <linux/kernel.h>
  10 #include <linux/sched.h>
  11 #include <linux/cpumask.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/compiler.h>
  14 #include <linux/sched/task_stack.h>
  15 #include <linux/smp.h>
  16
  17 #include <linux/atomic.h>
  18 #include <asm/cacheflush.h>
  19 #include <asm/cpu.h>
  20 #include <asm/processor.h>
  21 #include <asm/hardirq.h>
  22 #include <asm/mmu_context.h>
  23 #include <asm/time.h>
  24 #include <asm/mipsregs.h>
  25 #include <asm/mipsmtregs.h>
  26 #include <asm/mips_mt.h>
  27 #include <asm/mips-cps.h>
  28
  29 static void __init smvp_copy_vpe_config(void)
  30 {
  31         write_vpe_c0_status(
  32                 (read_c0_status() & ~(ST0_IM | ST0_IE | ST0_KSU)) | ST0_CU0);
  33
  34         /* set config to be the same as vpe0, particularly kseg0 coherency alg */
  35         write_vpe_c0_config( read_c0_config());
  36
  37         /* make sure there are no software interrupts pending */
  38         write_vpe_c0_cause(0);
  39
  40         /* Propagate Config7 */
  41         write_vpe_c0_config7(read_c0_config7());
  42
  43         write_vpe_c0_count(read_c0_count());
  44 }
  45
  46 static unsigned int __init smvp_vpe_init(unsigned int tc, unsigned int mvpconf0,
  47         unsigned int ncpu)
  48 {
  49         if (tc >= smp_max_threads ||
  50                 (tc > ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT)))
  51                 return ncpu;
  52
  53         /* Deactivate all but VPE 0 */
  54         if (tc != 0) {
  55                 unsigned long tmp = read_vpe_c0_vpeconf0();
  56
  57                 tmp &= ~VPECONF0_VPA;
  58
  59                 /* master VPE */
  60                 tmp |= VPECONF0_MVP;
  61                 write_vpe_c0_vpeconf0(tmp);
  62
  63                 /* Record this as available CPU */
  64                 set_cpu_possible(tc, true);
  65                 set_cpu_present(tc, true);
  66                 __cpu_number_map[tc]    = ++ncpu;
  67                 __cpu_logical_map[ncpu] = tc;
  68         }
  69
  70         /* Disable multi-threading with TC's */
  71         write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() & ~VPECONTROL_TE);
  72
  73         if (tc != 0)
  74                 smvp_copy_vpe_config();
  75
  76         cpu_set_vpe_id(&cpu_data[ncpu], tc);
  77
  78         return ncpu;
  79 }
  80
  81 static void __init smvp_tc_init(unsigned int tc, unsigned int mvpconf0)
  82 {
  83         unsigned long tmp;
  84
  85         if (!tc)
  86                 return;
  87
  88         /* bind a TC to each VPE, May as well put all excess TC's
  89            on the last VPE */
  90         if (tc >= (((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT)+1))
  91                 write_tc_c0_tcbind(read_tc_c0_tcbind() | ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT));
  92         else {
  93                 write_tc_c0_tcbind(read_tc_c0_tcbind() | tc);
  94
  95                 /* and set XTC */
  96                 write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | (tc << VPECONF0_XTC_SHIFT));
  97         }
  98
  99         tmp = read_tc_c0_tcstatus();
 100
 101         /* mark not allocated and not dynamically allocatable */
 102         tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
 103         tmp |= TCSTATUS_IXMT;           /* interrupt exempt */
 104         write_tc_c0_tcstatus(tmp);
 105
 106         write_tc_c0_tchalt(TCHALT_H);
 107 }
 108
 109 static void vsmp_init_secondary(void)
 110 {
 111         /* This is Malta specific: IPI,performance and timer interrupts */
 112         if (mips_gic_present())
 113                 change_c0_status(ST0_IM, STATUSF_IP2 | STATUSF_IP3 |
 114                                          STATUSF_IP4 | STATUSF_IP5 |
 115                                          STATUSF_IP6 | STATUSF_IP7);
 116         else
 117                 change_c0_status(ST0_IM, STATUSF_IP0 | STATUSF_IP1 |
 118                                          STATUSF_IP6 | STATUSF_IP7);
 119 }
 120
 121 static void vsmp_smp_finish(void)
 122 {
 123         /* CDFIXME: remove this? */
 124         write_c0_compare(read_c0_count() + (8* mips_hpt_frequency/HZ));
 125
 126 #ifdef CONFIG_MIPS_MT_FPAFF
 127         /* If we have an FPU, enroll ourselves in the FPU-full mask */
 128         if (cpu_has_fpu)
 129                 cpumask_set_cpu(smp_processor_id(), &mt_fpu_cpumask);
 130 #endif /* CONFIG_MIPS_MT_FPAFF */
 131
 132         local_irq_enable();
 133 }
 134
 135 /*
 136  * Setup the PC, SP, and GP of a secondary processor and start it
 137  * running!
 138  * smp_bootstrap is the place to resume from
 139  * __KSTK_TOS(idle) is apparently the stack pointer
 140  * (unsigned long)idle->thread_info the gp
 141  * assumes a 1:1 mapping of TC => VPE
 142  */
 143 static int vsmp_boot_secondary(int cpu, struct task_struct *idle)
 144 {
 145         struct thread_info *gp = task_thread_info(idle);
 146         dvpe();
 147         set_c0_mvpcontrol(MVPCONTROL_VPC);
 148
 149         settc(cpu);
 150
 151         /* restart */
 152         write_tc_c0_tcrestart((unsigned long)&smp_bootstrap);
 153
 154         /* enable the tc this vpe/cpu will be running */
 155         write_tc_c0_tcstatus((read_tc_c0_tcstatus() & ~TCSTATUS_IXMT) | TCSTATUS_A);
 156
 157         write_tc_c0_tchalt(0);
 158
 159         /* enable the VPE */
 160         write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | VPECONF0_VPA);
 161
 162         /* stack pointer */
 163         write_tc_gpr_sp( __KSTK_TOS(idle));
 164
 165         /* global pointer */
 166         write_tc_gpr_gp((unsigned long)gp);
 167
 168         flush_icache_range((unsigned long)gp,
 169                            (unsigned long)(gp + sizeof(struct thread_info)));
 170
 171         /* finally out of configuration and into chaos */
 172         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 173
 174         evpe(EVPE_ENABLE);
 175
 176         return 0;
 177 }
 178
 179 /*
 180  * Common setup before any secondaries are started
 181  * Make sure all CPU's are in a sensible state before we boot any of the
 182  * secondaries
 183  */
 184 static void __init vsmp_smp_setup(void)
 185 {
 186         unsigned int mvpconf0, ntc, tc, ncpu = 0;
 187         unsigned int nvpe;
 188
 189 #ifdef CONFIG_MIPS_MT_FPAFF
 190         /* If we have an FPU, enroll ourselves in the FPU-full mask */
 191         if (cpu_has_fpu)
 192                 cpumask_set_cpu(0, &mt_fpu_cpumask);
 193 #endif /* CONFIG_MIPS_MT_FPAFF */
 194         if (!cpu_has_mipsmt)
 195                 return;
 196
 197         /* disable MT so we can configure */
 198         dvpe();
 199         dmt();
 200
 201         /* Put MVPE's into 'configuration state' */
 202         set_c0_mvpcontrol(MVPCONTROL_VPC);
 203
 204         mvpconf0 = read_c0_mvpconf0();
 205         ntc = (mvpconf0 & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT;
 206
 207         nvpe = ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
 208         smp_num_siblings = nvpe;
 209
 210         /* we'll always have more TC's than VPE's, so loop setting everything
 211            to a sensible state */
 212         for (tc = 0; tc <= ntc; tc++) {
 213                 settc(tc);
 214
 215                 smvp_tc_init(tc, mvpconf0);
 216                 ncpu = smvp_vpe_init(tc, mvpconf0, ncpu);
 217         }
 218
 219         /* Release config state */
 220         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 221
 222         /* We'll wait until starting the secondaries before starting MVPE */
 223
 224         printk(KERN_INFO "Detected %i available secondary CPU(s)\n", ncpu);
 225 }
 226
 227 static void __init vsmp_prepare_cpus(unsigned int max_cpus)
 228 {
 229         mips_mt_set_cpuoptions();
 230 }
 231
 232 const struct plat_smp_ops vsmp_smp_ops = {
 233         .send_ipi_single        = mips_smp_send_ipi_single,
 234         .send_ipi_mask          = mips_smp_send_ipi_mask,
 235         .init_secondary         = vsmp_init_secondary,
 236         .smp_finish             = vsmp_smp_finish,
 237         .boot_secondary         = vsmp_boot_secondary,
 238         .smp_setup              = vsmp_smp_setup,
 239         .prepare_cpus           = vsmp_prepare_cpus,
 240 };
 241