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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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5b0093f3a4
If there is no online CPU within a core which could receive the IPI to start another VP in that core, a BUG() is triggered. Instead print a warning and gracefully handle the failure such that the system remains usable, albeit without the requested secondary CPU. Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Qais Yousef <qsyousef@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14504/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
588 lines
14 KiB
C
588 lines
14 KiB
C
/*
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* Copyright (C) 2013 Imagination Technologies
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* Author: Paul Burton <paul.burton@imgtec.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/delay.h>
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#include <linux/io.h>
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#include <linux/irqchip/mips-gic.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/smp.h>
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#include <linux/types.h>
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#include <asm/bcache.h>
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#include <asm/mips-cm.h>
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#include <asm/mips-cpc.h>
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#include <asm/mips_mt.h>
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#include <asm/mipsregs.h>
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#include <asm/pm-cps.h>
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#include <asm/r4kcache.h>
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#include <asm/smp-cps.h>
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#include <asm/time.h>
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#include <asm/uasm.h>
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static bool threads_disabled;
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static DECLARE_BITMAP(core_power, NR_CPUS);
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struct core_boot_config *mips_cps_core_bootcfg;
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static int __init setup_nothreads(char *s)
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{
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threads_disabled = true;
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return 0;
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}
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early_param("nothreads", setup_nothreads);
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static unsigned core_vpe_count(unsigned core)
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{
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unsigned cfg;
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if (threads_disabled)
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return 1;
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if ((!IS_ENABLED(CONFIG_MIPS_MT_SMP) || !cpu_has_mipsmt)
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&& (!IS_ENABLED(CONFIG_CPU_MIPSR6) || !cpu_has_vp))
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return 1;
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mips_cm_lock_other(core, 0);
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cfg = read_gcr_co_config() & CM_GCR_Cx_CONFIG_PVPE_MSK;
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mips_cm_unlock_other();
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return (cfg >> CM_GCR_Cx_CONFIG_PVPE_SHF) + 1;
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}
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static void __init cps_smp_setup(void)
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{
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unsigned int ncores, nvpes, core_vpes;
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unsigned long core_entry;
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int c, v;
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/* Detect & record VPE topology */
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ncores = mips_cm_numcores();
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pr_info("%s topology ", cpu_has_mips_r6 ? "VP" : "VPE");
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for (c = nvpes = 0; c < ncores; c++) {
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core_vpes = core_vpe_count(c);
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pr_cont("%c%u", c ? ',' : '{', core_vpes);
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/* Use the number of VPEs in core 0 for smp_num_siblings */
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if (!c)
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smp_num_siblings = core_vpes;
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for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) {
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cpu_data[nvpes + v].core = c;
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#if defined(CONFIG_MIPS_MT_SMP) || defined(CONFIG_CPU_MIPSR6)
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cpu_data[nvpes + v].vpe_id = v;
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#endif
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}
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nvpes += core_vpes;
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}
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pr_cont("} total %u\n", nvpes);
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/* Indicate present CPUs (CPU being synonymous with VPE) */
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for (v = 0; v < min_t(unsigned, nvpes, NR_CPUS); v++) {
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set_cpu_possible(v, true);
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set_cpu_present(v, true);
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__cpu_number_map[v] = v;
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__cpu_logical_map[v] = v;
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}
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/* Set a coherent default CCA (CWB) */
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change_c0_config(CONF_CM_CMASK, 0x5);
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/* Core 0 is powered up (we're running on it) */
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bitmap_set(core_power, 0, 1);
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/* Initialise core 0 */
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mips_cps_core_init();
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/* Make core 0 coherent with everything */
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write_gcr_cl_coherence(0xff);
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if (mips_cm_revision() >= CM_REV_CM3) {
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core_entry = CKSEG1ADDR((unsigned long)mips_cps_core_entry);
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write_gcr_bev_base(core_entry);
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}
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#ifdef CONFIG_MIPS_MT_FPAFF
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/* If we have an FPU, enroll ourselves in the FPU-full mask */
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if (cpu_has_fpu)
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cpumask_set_cpu(0, &mt_fpu_cpumask);
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#endif /* CONFIG_MIPS_MT_FPAFF */
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}
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static void __init cps_prepare_cpus(unsigned int max_cpus)
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{
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unsigned ncores, core_vpes, c, cca;
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bool cca_unsuitable;
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u32 *entry_code;
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mips_mt_set_cpuoptions();
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/* Detect whether the CCA is unsuited to multi-core SMP */
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cca = read_c0_config() & CONF_CM_CMASK;
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switch (cca) {
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case 0x4: /* CWBE */
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case 0x5: /* CWB */
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/* The CCA is coherent, multi-core is fine */
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cca_unsuitable = false;
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break;
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default:
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/* CCA is not coherent, multi-core is not usable */
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cca_unsuitable = true;
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}
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/* Warn the user if the CCA prevents multi-core */
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ncores = mips_cm_numcores();
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if (cca_unsuitable && ncores > 1) {
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pr_warn("Using only one core due to unsuitable CCA 0x%x\n",
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cca);
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for_each_present_cpu(c) {
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if (cpu_data[c].core)
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set_cpu_present(c, false);
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}
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}
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/*
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* Patch the start of mips_cps_core_entry to provide:
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*
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* s0 = kseg0 CCA
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*/
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entry_code = (u32 *)&mips_cps_core_entry;
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uasm_i_addiu(&entry_code, 16, 0, cca);
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blast_dcache_range((unsigned long)&mips_cps_core_entry,
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(unsigned long)entry_code);
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bc_wback_inv((unsigned long)&mips_cps_core_entry,
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(void *)entry_code - (void *)&mips_cps_core_entry);
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__sync();
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/* Allocate core boot configuration structs */
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mips_cps_core_bootcfg = kcalloc(ncores, sizeof(*mips_cps_core_bootcfg),
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GFP_KERNEL);
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if (!mips_cps_core_bootcfg) {
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pr_err("Failed to allocate boot config for %u cores\n", ncores);
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goto err_out;
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}
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/* Allocate VPE boot configuration structs */
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for (c = 0; c < ncores; c++) {
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core_vpes = core_vpe_count(c);
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mips_cps_core_bootcfg[c].vpe_config = kcalloc(core_vpes,
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sizeof(*mips_cps_core_bootcfg[c].vpe_config),
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GFP_KERNEL);
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if (!mips_cps_core_bootcfg[c].vpe_config) {
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pr_err("Failed to allocate %u VPE boot configs\n",
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core_vpes);
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goto err_out;
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}
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}
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/* Mark this CPU as booted */
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atomic_set(&mips_cps_core_bootcfg[current_cpu_data.core].vpe_mask,
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1 << cpu_vpe_id(¤t_cpu_data));
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return;
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err_out:
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/* Clean up allocations */
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if (mips_cps_core_bootcfg) {
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for (c = 0; c < ncores; c++)
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kfree(mips_cps_core_bootcfg[c].vpe_config);
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kfree(mips_cps_core_bootcfg);
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mips_cps_core_bootcfg = NULL;
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}
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/* Effectively disable SMP by declaring CPUs not present */
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for_each_possible_cpu(c) {
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if (c == 0)
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continue;
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set_cpu_present(c, false);
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}
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}
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static void boot_core(unsigned int core, unsigned int vpe_id)
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{
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u32 access, stat, seq_state;
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unsigned timeout;
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/* Select the appropriate core */
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mips_cm_lock_other(core, 0);
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/* Set its reset vector */
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write_gcr_co_reset_base(CKSEG1ADDR((unsigned long)mips_cps_core_entry));
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/* Ensure its coherency is disabled */
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write_gcr_co_coherence(0);
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/* Start it with the legacy memory map and exception base */
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write_gcr_co_reset_ext_base(CM_GCR_RESET_EXT_BASE_UEB);
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/* Ensure the core can access the GCRs */
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access = read_gcr_access();
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access |= 1 << (CM_GCR_ACCESS_ACCESSEN_SHF + core);
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write_gcr_access(access);
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if (mips_cpc_present()) {
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/* Reset the core */
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mips_cpc_lock_other(core);
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if (mips_cm_revision() >= CM_REV_CM3) {
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/* Run only the requested VP following the reset */
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write_cpc_co_vp_stop(0xf);
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write_cpc_co_vp_run(1 << vpe_id);
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/*
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* Ensure that the VP_RUN register is written before the
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* core leaves reset.
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*/
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wmb();
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}
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write_cpc_co_cmd(CPC_Cx_CMD_RESET);
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timeout = 100;
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while (true) {
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stat = read_cpc_co_stat_conf();
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seq_state = stat & CPC_Cx_STAT_CONF_SEQSTATE_MSK;
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/* U6 == coherent execution, ie. the core is up */
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if (seq_state == CPC_Cx_STAT_CONF_SEQSTATE_U6)
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break;
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/* Delay a little while before we start warning */
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if (timeout) {
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timeout--;
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mdelay(10);
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continue;
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}
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pr_warn("Waiting for core %u to start... STAT_CONF=0x%x\n",
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core, stat);
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mdelay(1000);
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}
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mips_cpc_unlock_other();
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} else {
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/* Take the core out of reset */
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write_gcr_co_reset_release(0);
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}
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mips_cm_unlock_other();
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/* The core is now powered up */
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bitmap_set(core_power, core, 1);
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}
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static void remote_vpe_boot(void *dummy)
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{
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unsigned core = current_cpu_data.core;
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struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core];
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mips_cps_boot_vpes(core_cfg, cpu_vpe_id(¤t_cpu_data));
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}
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static void cps_boot_secondary(int cpu, struct task_struct *idle)
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{
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unsigned core = cpu_data[cpu].core;
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unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
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struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core];
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struct vpe_boot_config *vpe_cfg = &core_cfg->vpe_config[vpe_id];
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unsigned long core_entry;
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unsigned int remote;
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int err;
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vpe_cfg->pc = (unsigned long)&smp_bootstrap;
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vpe_cfg->sp = __KSTK_TOS(idle);
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vpe_cfg->gp = (unsigned long)task_thread_info(idle);
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atomic_or(1 << cpu_vpe_id(&cpu_data[cpu]), &core_cfg->vpe_mask);
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preempt_disable();
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if (!test_bit(core, core_power)) {
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/* Boot a VPE on a powered down core */
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boot_core(core, vpe_id);
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goto out;
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}
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if (cpu_has_vp) {
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mips_cm_lock_other(core, vpe_id);
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core_entry = CKSEG1ADDR((unsigned long)mips_cps_core_entry);
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write_gcr_co_reset_base(core_entry);
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mips_cm_unlock_other();
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}
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if (core != current_cpu_data.core) {
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/* Boot a VPE on another powered up core */
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for (remote = 0; remote < NR_CPUS; remote++) {
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if (cpu_data[remote].core != core)
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continue;
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if (cpu_online(remote))
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break;
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}
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if (remote >= NR_CPUS) {
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pr_crit("No online CPU in core %u to start CPU%d\n",
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core, cpu);
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goto out;
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}
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err = smp_call_function_single(remote, remote_vpe_boot,
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NULL, 1);
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if (err)
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panic("Failed to call remote CPU\n");
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goto out;
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}
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BUG_ON(!cpu_has_mipsmt && !cpu_has_vp);
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/* Boot a VPE on this core */
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mips_cps_boot_vpes(core_cfg, vpe_id);
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out:
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preempt_enable();
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}
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static void cps_init_secondary(void)
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{
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/* Disable MT - we only want to run 1 TC per VPE */
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if (cpu_has_mipsmt)
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dmt();
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if (mips_cm_revision() >= CM_REV_CM3) {
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unsigned ident = gic_read_local_vp_id();
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/*
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* Ensure that our calculation of the VP ID matches up with
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* what the GIC reports, otherwise we'll have configured
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* interrupts incorrectly.
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*/
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BUG_ON(ident != mips_cm_vp_id(smp_processor_id()));
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}
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if (cpu_has_veic)
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clear_c0_status(ST0_IM);
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else
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change_c0_status(ST0_IM, STATUSF_IP2 | STATUSF_IP3 |
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STATUSF_IP4 | STATUSF_IP5 |
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STATUSF_IP6 | STATUSF_IP7);
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}
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static void cps_smp_finish(void)
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{
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write_c0_compare(read_c0_count() + (8 * mips_hpt_frequency / HZ));
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#ifdef CONFIG_MIPS_MT_FPAFF
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/* If we have an FPU, enroll ourselves in the FPU-full mask */
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if (cpu_has_fpu)
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cpumask_set_cpu(smp_processor_id(), &mt_fpu_cpumask);
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#endif /* CONFIG_MIPS_MT_FPAFF */
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local_irq_enable();
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}
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#ifdef CONFIG_HOTPLUG_CPU
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static int cps_cpu_disable(void)
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{
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unsigned cpu = smp_processor_id();
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struct core_boot_config *core_cfg;
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if (!cpu)
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return -EBUSY;
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if (!cps_pm_support_state(CPS_PM_POWER_GATED))
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return -EINVAL;
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core_cfg = &mips_cps_core_bootcfg[current_cpu_data.core];
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atomic_sub(1 << cpu_vpe_id(¤t_cpu_data), &core_cfg->vpe_mask);
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smp_mb__after_atomic();
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set_cpu_online(cpu, false);
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calculate_cpu_foreign_map();
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return 0;
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}
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static DECLARE_COMPLETION(cpu_death_chosen);
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static unsigned cpu_death_sibling;
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static enum {
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CPU_DEATH_HALT,
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CPU_DEATH_POWER,
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} cpu_death;
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void play_dead(void)
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{
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unsigned int cpu, core, vpe_id;
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local_irq_disable();
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idle_task_exit();
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cpu = smp_processor_id();
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cpu_death = CPU_DEATH_POWER;
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pr_debug("CPU%d going offline\n", cpu);
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if (cpu_has_mipsmt || cpu_has_vp) {
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core = cpu_data[cpu].core;
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/* Look for another online VPE within the core */
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for_each_online_cpu(cpu_death_sibling) {
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if (cpu_data[cpu_death_sibling].core != core)
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continue;
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/*
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* There is an online VPE within the core. Just halt
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* this TC and leave the core alone.
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*/
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cpu_death = CPU_DEATH_HALT;
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break;
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}
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}
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/* This CPU has chosen its way out */
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complete(&cpu_death_chosen);
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if (cpu_death == CPU_DEATH_HALT) {
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vpe_id = cpu_vpe_id(&cpu_data[cpu]);
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pr_debug("Halting core %d VP%d\n", core, vpe_id);
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if (cpu_has_mipsmt) {
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/* Halt this TC */
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write_c0_tchalt(TCHALT_H);
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instruction_hazard();
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} else if (cpu_has_vp) {
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write_cpc_cl_vp_stop(1 << vpe_id);
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/* Ensure that the VP_STOP register is written */
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wmb();
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}
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} else {
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pr_debug("Gating power to core %d\n", core);
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/* Power down the core */
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cps_pm_enter_state(CPS_PM_POWER_GATED);
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}
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/* This should never be reached */
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panic("Failed to offline CPU %u", cpu);
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}
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static void wait_for_sibling_halt(void *ptr_cpu)
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{
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unsigned cpu = (unsigned long)ptr_cpu;
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unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
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unsigned halted;
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unsigned long flags;
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do {
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local_irq_save(flags);
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settc(vpe_id);
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halted = read_tc_c0_tchalt();
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local_irq_restore(flags);
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} while (!(halted & TCHALT_H));
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}
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static void cps_cpu_die(unsigned int cpu)
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{
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unsigned core = cpu_data[cpu].core;
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unsigned int vpe_id = cpu_vpe_id(&cpu_data[cpu]);
|
|
unsigned stat;
|
|
int err;
|
|
|
|
/* Wait for the cpu to choose its way out */
|
|
if (!wait_for_completion_timeout(&cpu_death_chosen,
|
|
msecs_to_jiffies(5000))) {
|
|
pr_err("CPU%u: didn't offline\n", cpu);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Now wait for the CPU to actually offline. Without doing this that
|
|
* offlining may race with one or more of:
|
|
*
|
|
* - Onlining the CPU again.
|
|
* - Powering down the core if another VPE within it is offlined.
|
|
* - A sibling VPE entering a non-coherent state.
|
|
*
|
|
* In the non-MT halt case (ie. infinite loop) the CPU is doing nothing
|
|
* with which we could race, so do nothing.
|
|
*/
|
|
if (cpu_death == CPU_DEATH_POWER) {
|
|
/*
|
|
* Wait for the core to enter a powered down or clock gated
|
|
* state, the latter happening when a JTAG probe is connected
|
|
* in which case the CPC will refuse to power down the core.
|
|
*/
|
|
do {
|
|
mips_cm_lock_other(core, 0);
|
|
mips_cpc_lock_other(core);
|
|
stat = read_cpc_co_stat_conf();
|
|
stat &= CPC_Cx_STAT_CONF_SEQSTATE_MSK;
|
|
mips_cpc_unlock_other();
|
|
mips_cm_unlock_other();
|
|
} while (stat != CPC_Cx_STAT_CONF_SEQSTATE_D0 &&
|
|
stat != CPC_Cx_STAT_CONF_SEQSTATE_D2 &&
|
|
stat != CPC_Cx_STAT_CONF_SEQSTATE_U2);
|
|
|
|
/* Indicate the core is powered off */
|
|
bitmap_clear(core_power, core, 1);
|
|
} else if (cpu_has_mipsmt) {
|
|
/*
|
|
* Have a CPU with access to the offlined CPUs registers wait
|
|
* for its TC to halt.
|
|
*/
|
|
err = smp_call_function_single(cpu_death_sibling,
|
|
wait_for_sibling_halt,
|
|
(void *)(unsigned long)cpu, 1);
|
|
if (err)
|
|
panic("Failed to call remote sibling CPU\n");
|
|
} else if (cpu_has_vp) {
|
|
do {
|
|
mips_cm_lock_other(core, vpe_id);
|
|
stat = read_cpc_co_vp_running();
|
|
mips_cm_unlock_other();
|
|
} while (stat & (1 << vpe_id));
|
|
}
|
|
}
|
|
|
|
#endif /* CONFIG_HOTPLUG_CPU */
|
|
|
|
static struct plat_smp_ops cps_smp_ops = {
|
|
.smp_setup = cps_smp_setup,
|
|
.prepare_cpus = cps_prepare_cpus,
|
|
.boot_secondary = cps_boot_secondary,
|
|
.init_secondary = cps_init_secondary,
|
|
.smp_finish = cps_smp_finish,
|
|
.send_ipi_single = mips_smp_send_ipi_single,
|
|
.send_ipi_mask = mips_smp_send_ipi_mask,
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
.cpu_disable = cps_cpu_disable,
|
|
.cpu_die = cps_cpu_die,
|
|
#endif
|
|
};
|
|
|
|
bool mips_cps_smp_in_use(void)
|
|
{
|
|
extern struct plat_smp_ops *mp_ops;
|
|
return mp_ops == &cps_smp_ops;
|
|
}
|
|
|
|
int register_cps_smp_ops(void)
|
|
{
|
|
if (!mips_cm_present()) {
|
|
pr_warn("MIPS CPS SMP unable to proceed without a CM\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
/* check we have a GIC - we need one for IPIs */
|
|
if (!(read_gcr_gic_status() & CM_GCR_GIC_STATUS_EX_MSK)) {
|
|
pr_warn("MIPS CPS SMP unable to proceed without a GIC\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
register_smp_ops(&cps_smp_ops);
|
|
return 0;
|
|
}
|