diff options
Diffstat (limited to 'arch/mips/kernel/pm-cps.c')
| -rw-r--r-- | arch/mips/kernel/pm-cps.c | 738 |
1 files changed, 738 insertions, 0 deletions
diff --git a/arch/mips/kernel/pm-cps.c b/arch/mips/kernel/pm-cps.c new file mode 100644 index 0000000000..9bf60d7d44 --- /dev/null +++ b/arch/mips/kernel/pm-cps.c @@ -0,0 +1,738 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2014 Imagination Technologies + * Author: Paul Burton <paul.burton@mips.com> + */ + +#include <linux/cpuhotplug.h> +#include <linux/init.h> +#include <linux/percpu.h> +#include <linux/slab.h> +#include <linux/suspend.h> + +#include <asm/asm-offsets.h> +#include <asm/cacheflush.h> +#include <asm/cacheops.h> +#include <asm/idle.h> +#include <asm/mips-cps.h> +#include <asm/mipsmtregs.h> +#include <asm/pm.h> +#include <asm/pm-cps.h> +#include <asm/smp-cps.h> +#include <asm/uasm.h> + +/* + * cps_nc_entry_fn - type of a generated non-coherent state entry function + * @online: the count of online coupled VPEs + * @nc_ready_count: pointer to a non-coherent mapping of the core ready_count + * + * The code entering & exiting non-coherent states is generated at runtime + * using uasm, in order to ensure that the compiler cannot insert a stray + * memory access at an unfortunate time and to allow the generation of optimal + * core-specific code particularly for cache routines. If coupled_coherence + * is non-zero and this is the entry function for the CPS_PM_NC_WAIT state, + * returns the number of VPEs that were in the wait state at the point this + * VPE left it. Returns garbage if coupled_coherence is zero or this is not + * the entry function for CPS_PM_NC_WAIT. + */ +typedef unsigned (*cps_nc_entry_fn)(unsigned online, u32 *nc_ready_count); + +/* + * The entry point of the generated non-coherent idle state entry/exit + * functions. Actually per-core rather than per-CPU. + */ +static DEFINE_PER_CPU_READ_MOSTLY(cps_nc_entry_fn[CPS_PM_STATE_COUNT], + nc_asm_enter); + +/* Bitmap indicating which states are supported by the system */ +static DECLARE_BITMAP(state_support, CPS_PM_STATE_COUNT); + +/* + * Indicates the number of coupled VPEs ready to operate in a non-coherent + * state. Actually per-core rather than per-CPU. + */ +static DEFINE_PER_CPU_ALIGNED(u32*, ready_count); + +/* Indicates online CPUs coupled with the current CPU */ +static DEFINE_PER_CPU_ALIGNED(cpumask_t, online_coupled); + +/* + * Used to synchronize entry to deep idle states. Actually per-core rather + * than per-CPU. + */ +static DEFINE_PER_CPU_ALIGNED(atomic_t, pm_barrier); + +/* Saved CPU state across the CPS_PM_POWER_GATED state */ +DEFINE_PER_CPU_ALIGNED(struct mips_static_suspend_state, cps_cpu_state); + +/* A somewhat arbitrary number of labels & relocs for uasm */ +static struct uasm_label labels[32]; +static struct uasm_reloc relocs[32]; + +enum mips_reg { + zero, at, v0, v1, a0, a1, a2, a3, + t0, t1, t2, t3, t4, t5, t6, t7, + s0, s1, s2, s3, s4, s5, s6, s7, + t8, t9, k0, k1, gp, sp, fp, ra, +}; + +bool cps_pm_support_state(enum cps_pm_state state) +{ + return test_bit(state, state_support); +} + +static void coupled_barrier(atomic_t *a, unsigned online) +{ + /* + * This function is effectively the same as + * cpuidle_coupled_parallel_barrier, which can't be used here since + * there's no cpuidle device. + */ + + if (!coupled_coherence) + return; + + smp_mb__before_atomic(); + atomic_inc(a); + + while (atomic_read(a) < online) + cpu_relax(); + + if (atomic_inc_return(a) == online * 2) { + atomic_set(a, 0); + return; + } + + while (atomic_read(a) > online) + cpu_relax(); +} + +int cps_pm_enter_state(enum cps_pm_state state) +{ + unsigned cpu = smp_processor_id(); + unsigned core = cpu_core(¤t_cpu_data); + unsigned online, left; + cpumask_t *coupled_mask = this_cpu_ptr(&online_coupled); + u32 *core_ready_count, *nc_core_ready_count; + void *nc_addr; + cps_nc_entry_fn entry; + struct core_boot_config *core_cfg; + struct vpe_boot_config *vpe_cfg; + + /* Check that there is an entry function for this state */ + entry = per_cpu(nc_asm_enter, core)[state]; + if (!entry) + return -EINVAL; + + /* Calculate which coupled CPUs (VPEs) are online */ +#if defined(CONFIG_MIPS_MT) || defined(CONFIG_CPU_MIPSR6) + if (cpu_online(cpu)) { + cpumask_and(coupled_mask, cpu_online_mask, + &cpu_sibling_map[cpu]); + online = cpumask_weight(coupled_mask); + cpumask_clear_cpu(cpu, coupled_mask); + } else +#endif + { + cpumask_clear(coupled_mask); + online = 1; + } + + /* Setup the VPE to run mips_cps_pm_restore when started again */ + if (IS_ENABLED(CONFIG_CPU_PM) && state == CPS_PM_POWER_GATED) { + /* Power gating relies upon CPS SMP */ + if (!mips_cps_smp_in_use()) + return -EINVAL; + + core_cfg = &mips_cps_core_bootcfg[core]; + vpe_cfg = &core_cfg->vpe_config[cpu_vpe_id(¤t_cpu_data)]; + vpe_cfg->pc = (unsigned long)mips_cps_pm_restore; + vpe_cfg->gp = (unsigned long)current_thread_info(); + vpe_cfg->sp = 0; + } + + /* Indicate that this CPU might not be coherent */ + cpumask_clear_cpu(cpu, &cpu_coherent_mask); + smp_mb__after_atomic(); + + /* Create a non-coherent mapping of the core ready_count */ + core_ready_count = per_cpu(ready_count, core); + nc_addr = kmap_noncoherent(virt_to_page(core_ready_count), + (unsigned long)core_ready_count); + nc_addr += ((unsigned long)core_ready_count & ~PAGE_MASK); + nc_core_ready_count = nc_addr; + + /* Ensure ready_count is zero-initialised before the assembly runs */ + WRITE_ONCE(*nc_core_ready_count, 0); + coupled_barrier(&per_cpu(pm_barrier, core), online); + + /* Run the generated entry code */ + left = entry(online, nc_core_ready_count); + + /* Remove the non-coherent mapping of ready_count */ + kunmap_noncoherent(); + + /* Indicate that this CPU is definitely coherent */ + cpumask_set_cpu(cpu, &cpu_coherent_mask); + + /* + * If this VPE is the first to leave the non-coherent wait state then + * it needs to wake up any coupled VPEs still running their wait + * instruction so that they return to cpuidle, which can then complete + * coordination between the coupled VPEs & provide the governor with + * a chance to reflect on the length of time the VPEs were in the + * idle state. + */ + if (coupled_coherence && (state == CPS_PM_NC_WAIT) && (left == online)) + arch_send_call_function_ipi_mask(coupled_mask); + + return 0; +} + +static void cps_gen_cache_routine(u32 **pp, struct uasm_label **pl, + struct uasm_reloc **pr, + const struct cache_desc *cache, + unsigned op, int lbl) +{ + unsigned cache_size = cache->ways << cache->waybit; + unsigned i; + const unsigned unroll_lines = 32; + + /* If the cache isn't present this function has it easy */ + if (cache->flags & MIPS_CACHE_NOT_PRESENT) + return; + + /* Load base address */ + UASM_i_LA(pp, t0, (long)CKSEG0); + + /* Calculate end address */ + if (cache_size < 0x8000) + uasm_i_addiu(pp, t1, t0, cache_size); + else + UASM_i_LA(pp, t1, (long)(CKSEG0 + cache_size)); + + /* Start of cache op loop */ + uasm_build_label(pl, *pp, lbl); + + /* Generate the cache ops */ + for (i = 0; i < unroll_lines; i++) { + if (cpu_has_mips_r6) { + uasm_i_cache(pp, op, 0, t0); + uasm_i_addiu(pp, t0, t0, cache->linesz); + } else { + uasm_i_cache(pp, op, i * cache->linesz, t0); + } + } + + if (!cpu_has_mips_r6) + /* Update the base address */ + uasm_i_addiu(pp, t0, t0, unroll_lines * cache->linesz); + + /* Loop if we haven't reached the end address yet */ + uasm_il_bne(pp, pr, t0, t1, lbl); + uasm_i_nop(pp); +} + +static int cps_gen_flush_fsb(u32 **pp, struct uasm_label **pl, + struct uasm_reloc **pr, + const struct cpuinfo_mips *cpu_info, + int lbl) +{ + unsigned i, fsb_size = 8; + unsigned num_loads = (fsb_size * 3) / 2; + unsigned line_stride = 2; + unsigned line_size = cpu_info->dcache.linesz; + unsigned perf_counter, perf_event; + unsigned revision = cpu_info->processor_id & PRID_REV_MASK; + + /* + * Determine whether this CPU requires an FSB flush, and if so which + * performance counter/event reflect stalls due to a full FSB. + */ + switch (__get_cpu_type(cpu_info->cputype)) { + case CPU_INTERAPTIV: + perf_counter = 1; + perf_event = 51; + break; + + case CPU_PROAPTIV: + /* Newer proAptiv cores don't require this workaround */ + if (revision >= PRID_REV_ENCODE_332(1, 1, 0)) + return 0; + + /* On older ones it's unavailable */ + return -1; + + default: + /* Assume that the CPU does not need this workaround */ + return 0; + } + + /* + * Ensure that the fill/store buffer (FSB) is not holding the results + * of a prefetch, since if it is then the CPC sequencer may become + * stuck in the D3 (ClrBus) state whilst entering a low power state. + */ + + /* Preserve perf counter setup */ + uasm_i_mfc0(pp, t2, 25, (perf_counter * 2) + 0); /* PerfCtlN */ + uasm_i_mfc0(pp, t3, 25, (perf_counter * 2) + 1); /* PerfCntN */ + + /* Setup perf counter to count FSB full pipeline stalls */ + uasm_i_addiu(pp, t0, zero, (perf_event << 5) | 0xf); + uasm_i_mtc0(pp, t0, 25, (perf_counter * 2) + 0); /* PerfCtlN */ + uasm_i_ehb(pp); + uasm_i_mtc0(pp, zero, 25, (perf_counter * 2) + 1); /* PerfCntN */ + uasm_i_ehb(pp); + + /* Base address for loads */ + UASM_i_LA(pp, t0, (long)CKSEG0); + + /* Start of clear loop */ + uasm_build_label(pl, *pp, lbl); + + /* Perform some loads to fill the FSB */ + for (i = 0; i < num_loads; i++) + uasm_i_lw(pp, zero, i * line_size * line_stride, t0); + + /* + * Invalidate the new D-cache entries so that the cache will need + * refilling (via the FSB) if the loop is executed again. + */ + for (i = 0; i < num_loads; i++) { + uasm_i_cache(pp, Hit_Invalidate_D, + i * line_size * line_stride, t0); + uasm_i_cache(pp, Hit_Writeback_Inv_SD, + i * line_size * line_stride, t0); + } + + /* Barrier ensuring previous cache invalidates are complete */ + uasm_i_sync(pp, __SYNC_full); + uasm_i_ehb(pp); + + /* Check whether the pipeline stalled due to the FSB being full */ + uasm_i_mfc0(pp, t1, 25, (perf_counter * 2) + 1); /* PerfCntN */ + + /* Loop if it didn't */ + uasm_il_beqz(pp, pr, t1, lbl); + uasm_i_nop(pp); + + /* Restore perf counter 1. The count may well now be wrong... */ + uasm_i_mtc0(pp, t2, 25, (perf_counter * 2) + 0); /* PerfCtlN */ + uasm_i_ehb(pp); + uasm_i_mtc0(pp, t3, 25, (perf_counter * 2) + 1); /* PerfCntN */ + uasm_i_ehb(pp); + + return 0; +} + +static void cps_gen_set_top_bit(u32 **pp, struct uasm_label **pl, + struct uasm_reloc **pr, + unsigned r_addr, int lbl) +{ + uasm_i_lui(pp, t0, uasm_rel_hi(0x80000000)); + uasm_build_label(pl, *pp, lbl); + uasm_i_ll(pp, t1, 0, r_addr); + uasm_i_or(pp, t1, t1, t0); + uasm_i_sc(pp, t1, 0, r_addr); + uasm_il_beqz(pp, pr, t1, lbl); + uasm_i_nop(pp); +} + +static void *cps_gen_entry_code(unsigned cpu, enum cps_pm_state state) +{ + struct uasm_label *l = labels; + struct uasm_reloc *r = relocs; + u32 *buf, *p; + const unsigned r_online = a0; + const unsigned r_nc_count = a1; + const unsigned r_pcohctl = t7; + const unsigned max_instrs = 256; + unsigned cpc_cmd; + int err; + enum { + lbl_incready = 1, + lbl_poll_cont, + lbl_secondary_hang, + lbl_disable_coherence, + lbl_flush_fsb, + lbl_invicache, + lbl_flushdcache, + lbl_hang, + lbl_set_cont, + lbl_secondary_cont, + lbl_decready, + }; + + /* Allocate a buffer to hold the generated code */ + p = buf = kcalloc(max_instrs, sizeof(u32), GFP_KERNEL); + if (!buf) + return NULL; + + /* Clear labels & relocs ready for (re)use */ + memset(labels, 0, sizeof(labels)); + memset(relocs, 0, sizeof(relocs)); + + if (IS_ENABLED(CONFIG_CPU_PM) && state == CPS_PM_POWER_GATED) { + /* Power gating relies upon CPS SMP */ + if (!mips_cps_smp_in_use()) + goto out_err; + + /* + * Save CPU state. Note the non-standard calling convention + * with the return address placed in v0 to avoid clobbering + * the ra register before it is saved. + */ + UASM_i_LA(&p, t0, (long)mips_cps_pm_save); + uasm_i_jalr(&p, v0, t0); + uasm_i_nop(&p); + } + + /* + * Load addresses of required CM & CPC registers. This is done early + * because they're needed in both the enable & disable coherence steps + * but in the coupled case the enable step will only run on one VPE. + */ + UASM_i_LA(&p, r_pcohctl, (long)addr_gcr_cl_coherence()); + + if (coupled_coherence) { + /* Increment ready_count */ + uasm_i_sync(&p, __SYNC_mb); + uasm_build_label(&l, p, lbl_incready); + uasm_i_ll(&p, t1, 0, r_nc_count); + uasm_i_addiu(&p, t2, t1, 1); + uasm_i_sc(&p, t2, 0, r_nc_count); + uasm_il_beqz(&p, &r, t2, lbl_incready); + uasm_i_addiu(&p, t1, t1, 1); + + /* Barrier ensuring all CPUs see the updated r_nc_count value */ + uasm_i_sync(&p, __SYNC_mb); + + /* + * If this is the last VPE to become ready for non-coherence + * then it should branch below. + */ + uasm_il_beq(&p, &r, t1, r_online, lbl_disable_coherence); + uasm_i_nop(&p); + + if (state < CPS_PM_POWER_GATED) { + /* + * Otherwise this is not the last VPE to become ready + * for non-coherence. It needs to wait until coherence + * has been disabled before proceeding, which it will do + * by polling for the top bit of ready_count being set. + */ + uasm_i_addiu(&p, t1, zero, -1); + uasm_build_label(&l, p, lbl_poll_cont); + uasm_i_lw(&p, t0, 0, r_nc_count); + uasm_il_bltz(&p, &r, t0, lbl_secondary_cont); + uasm_i_ehb(&p); + if (cpu_has_mipsmt) + uasm_i_yield(&p, zero, t1); + uasm_il_b(&p, &r, lbl_poll_cont); + uasm_i_nop(&p); + } else { + /* + * The core will lose power & this VPE will not continue + * so it can simply halt here. + */ + if (cpu_has_mipsmt) { + /* Halt the VPE via C0 tchalt register */ + uasm_i_addiu(&p, t0, zero, TCHALT_H); + uasm_i_mtc0(&p, t0, 2, 4); + } else if (cpu_has_vp) { + /* Halt the VP via the CPC VP_STOP register */ + unsigned int vpe_id; + + vpe_id = cpu_vpe_id(&cpu_data[cpu]); + uasm_i_addiu(&p, t0, zero, 1 << vpe_id); + UASM_i_LA(&p, t1, (long)addr_cpc_cl_vp_stop()); + uasm_i_sw(&p, t0, 0, t1); + } else { + BUG(); + } + uasm_build_label(&l, p, lbl_secondary_hang); + uasm_il_b(&p, &r, lbl_secondary_hang); + uasm_i_nop(&p); + } + } + + /* + * This is the point of no return - this VPE will now proceed to + * disable coherence. At this point we *must* be sure that no other + * VPE within the core will interfere with the L1 dcache. + */ + uasm_build_label(&l, p, lbl_disable_coherence); + + /* Invalidate the L1 icache */ + cps_gen_cache_routine(&p, &l, &r, &cpu_data[cpu].icache, + Index_Invalidate_I, lbl_invicache); + + /* Writeback & invalidate the L1 dcache */ + cps_gen_cache_routine(&p, &l, &r, &cpu_data[cpu].dcache, + Index_Writeback_Inv_D, lbl_flushdcache); + + /* Barrier ensuring previous cache invalidates are complete */ + uasm_i_sync(&p, __SYNC_full); + uasm_i_ehb(&p); + + if (mips_cm_revision() < CM_REV_CM3) { + /* + * Disable all but self interventions. The load from COHCTL is + * defined by the interAptiv & proAptiv SUMs as ensuring that the + * operation resulting from the preceding store is complete. + */ + uasm_i_addiu(&p, t0, zero, 1 << cpu_core(&cpu_data[cpu])); + uasm_i_sw(&p, t0, 0, r_pcohctl); + uasm_i_lw(&p, t0, 0, r_pcohctl); + + /* Barrier to ensure write to coherence control is complete */ + uasm_i_sync(&p, __SYNC_full); + uasm_i_ehb(&p); + } + + /* Disable coherence */ + uasm_i_sw(&p, zero, 0, r_pcohctl); + uasm_i_lw(&p, t0, 0, r_pcohctl); + + if (state >= CPS_PM_CLOCK_GATED) { + err = cps_gen_flush_fsb(&p, &l, &r, &cpu_data[cpu], + lbl_flush_fsb); + if (err) + goto out_err; + + /* Determine the CPC command to issue */ + switch (state) { + case CPS_PM_CLOCK_GATED: + cpc_cmd = CPC_Cx_CMD_CLOCKOFF; + break; + case CPS_PM_POWER_GATED: + cpc_cmd = CPC_Cx_CMD_PWRDOWN; + break; + default: + BUG(); + goto out_err; + } + + /* Issue the CPC command */ + UASM_i_LA(&p, t0, (long)addr_cpc_cl_cmd()); + uasm_i_addiu(&p, t1, zero, cpc_cmd); + uasm_i_sw(&p, t1, 0, t0); + + if (state == CPS_PM_POWER_GATED) { + /* If anything goes wrong just hang */ + uasm_build_label(&l, p, lbl_hang); + uasm_il_b(&p, &r, lbl_hang); + uasm_i_nop(&p); + + /* + * There's no point generating more code, the core is + * powered down & if powered back up will run from the + * reset vector not from here. + */ + goto gen_done; + } + + /* Barrier to ensure write to CPC command is complete */ + uasm_i_sync(&p, __SYNC_full); + uasm_i_ehb(&p); + } + + if (state == CPS_PM_NC_WAIT) { + /* + * At this point it is safe for all VPEs to proceed with + * execution. This VPE will set the top bit of ready_count + * to indicate to the other VPEs that they may continue. + */ + if (coupled_coherence) + cps_gen_set_top_bit(&p, &l, &r, r_nc_count, + lbl_set_cont); + + /* + * VPEs which did not disable coherence will continue + * executing, after coherence has been disabled, from this + * point. + */ + uasm_build_label(&l, p, lbl_secondary_cont); + + /* Now perform our wait */ + uasm_i_wait(&p, 0); + } + + /* + * Re-enable coherence. Note that for CPS_PM_NC_WAIT all coupled VPEs + * will run this. The first will actually re-enable coherence & the + * rest will just be performing a rather unusual nop. + */ + uasm_i_addiu(&p, t0, zero, mips_cm_revision() < CM_REV_CM3 + ? CM_GCR_Cx_COHERENCE_COHDOMAINEN + : CM3_GCR_Cx_COHERENCE_COHEN); + + uasm_i_sw(&p, t0, 0, r_pcohctl); + uasm_i_lw(&p, t0, 0, r_pcohctl); + + /* Barrier to ensure write to coherence control is complete */ + uasm_i_sync(&p, __SYNC_full); + uasm_i_ehb(&p); + + if (coupled_coherence && (state == CPS_PM_NC_WAIT)) { + /* Decrement ready_count */ + uasm_build_label(&l, p, lbl_decready); + uasm_i_sync(&p, __SYNC_mb); + uasm_i_ll(&p, t1, 0, r_nc_count); + uasm_i_addiu(&p, t2, t1, -1); + uasm_i_sc(&p, t2, 0, r_nc_count); + uasm_il_beqz(&p, &r, t2, lbl_decready); + uasm_i_andi(&p, v0, t1, (1 << fls(smp_num_siblings)) - 1); + + /* Barrier ensuring all CPUs see the updated r_nc_count value */ + uasm_i_sync(&p, __SYNC_mb); + } + + if (coupled_coherence && (state == CPS_PM_CLOCK_GATED)) { + /* + * At this point it is safe for all VPEs to proceed with + * execution. This VPE will set the top bit of ready_count + * to indicate to the other VPEs that they may continue. + */ + cps_gen_set_top_bit(&p, &l, &r, r_nc_count, lbl_set_cont); + + /* + * This core will be reliant upon another core sending a + * power-up command to the CPC in order to resume operation. + * Thus an arbitrary VPE can't trigger the core leaving the + * idle state and the one that disables coherence might as well + * be the one to re-enable it. The rest will continue from here + * after that has been done. + */ + uasm_build_label(&l, p, lbl_secondary_cont); + + /* Barrier ensuring all CPUs see the updated r_nc_count value */ + uasm_i_sync(&p, __SYNC_mb); + } + + /* The core is coherent, time to return to C code */ + uasm_i_jr(&p, ra); + uasm_i_nop(&p); + +gen_done: + /* Ensure the code didn't exceed the resources allocated for it */ + BUG_ON((p - buf) > max_instrs); + BUG_ON((l - labels) > ARRAY_SIZE(labels)); + BUG_ON((r - relocs) > ARRAY_SIZE(relocs)); + + /* Patch branch offsets */ + uasm_resolve_relocs(relocs, labels); + + /* Flush the icache */ + local_flush_icache_range((unsigned long)buf, (unsigned long)p); + + return buf; +out_err: + kfree(buf); + return NULL; +} + +static int cps_pm_online_cpu(unsigned int cpu) +{ + enum cps_pm_state state; + unsigned core = cpu_core(&cpu_data[cpu]); + void *entry_fn, *core_rc; + + for (state = CPS_PM_NC_WAIT; state < CPS_PM_STATE_COUNT; state++) { + if (per_cpu(nc_asm_enter, core)[state]) + continue; + if (!test_bit(state, state_support)) + continue; + + entry_fn = cps_gen_entry_code(cpu, state); + if (!entry_fn) { + pr_err("Failed to generate core %u state %u entry\n", + core, state); + clear_bit(state, state_support); + } + + per_cpu(nc_asm_enter, core)[state] = entry_fn; + } + + if (!per_cpu(ready_count, core)) { + core_rc = kmalloc(sizeof(u32), GFP_KERNEL); + if (!core_rc) { + pr_err("Failed allocate core %u ready_count\n", core); + return -ENOMEM; + } + per_cpu(ready_count, core) = core_rc; + } + + return 0; +} + +static int cps_pm_power_notifier(struct notifier_block *this, + unsigned long event, void *ptr) +{ + unsigned int stat; + + switch (event) { + case PM_SUSPEND_PREPARE: + stat = read_cpc_cl_stat_conf(); + /* + * If we're attempting to suspend the system and power down all + * of the cores, the JTAG detect bit indicates that the CPC will + * instead put the cores into clock-off state. In this state + * a connected debugger can cause the CPU to attempt + * interactions with the powered down system. At best this will + * fail. At worst, it can hang the NoC, requiring a hard reset. + * To avoid this, just block system suspend if a JTAG probe + * is detected. + */ + if (stat & CPC_Cx_STAT_CONF_EJTAG_PROBE) { + pr_warn("JTAG probe is connected - abort suspend\n"); + return NOTIFY_BAD; + } + return NOTIFY_DONE; + default: + return NOTIFY_DONE; + } +} + +static int __init cps_pm_init(void) +{ + /* A CM is required for all non-coherent states */ + if (!mips_cm_present()) { + pr_warn("pm-cps: no CM, non-coherent states unavailable\n"); + return 0; + } + + /* + * If interrupts were enabled whilst running a wait instruction on a + * non-coherent core then the VPE may end up processing interrupts + * whilst non-coherent. That would be bad. + */ + if (cpu_wait == r4k_wait_irqoff) + set_bit(CPS_PM_NC_WAIT, state_support); + else + pr_warn("pm-cps: non-coherent wait unavailable\n"); + + /* Detect whether a CPC is present */ + if (mips_cpc_present()) { + /* Detect whether clock gating is implemented */ + if (read_cpc_cl_stat_conf() & CPC_Cx_STAT_CONF_CLKGAT_IMPL) + set_bit(CPS_PM_CLOCK_GATED, state_support); + else + pr_warn("pm-cps: CPC does not support clock gating\n"); + + /* Power gating is available with CPS SMP & any CPC */ + if (mips_cps_smp_in_use()) + set_bit(CPS_PM_POWER_GATED, state_support); + else + pr_warn("pm-cps: CPS SMP not in use, power gating unavailable\n"); + } else { + pr_warn("pm-cps: no CPC, clock & power gating unavailable\n"); + } + + pm_notifier(cps_pm_power_notifier, 0); + + return cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "mips/cps_pm:online", + cps_pm_online_cpu, NULL); +} +arch_initcall(cps_pm_init); |