/* * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 2011 by Kevin Cernekee (cernekee@gmail.com) * * SMP support for BMIPS */ #include <linux/init.h> #include <linux/sched.h> #include <linux/mm.h> #include <linux/delay.h> #include <linux/smp.h> #include <linux/interrupt.h> #include <linux/spinlock.h> #include <linux/cpu.h> #include <linux/cpumask.h> #include <linux/reboot.h> #include <linux/io.h> #include <linux/compiler.h> #include <linux/linkage.h> #include <linux/bug.h> #include <linux/kernel.h> #include <asm/time.h> #include <asm/pgtable.h> #include <asm/processor.h> #include <asm/bootinfo.h> #include <asm/pmon.h> #include <asm/cacheflush.h> #include <asm/tlbflush.h> #include <asm/mipsregs.h> #include <asm/bmips.h> #include <asm/traps.h> #include <asm/barrier.h> static int __maybe_unused max_cpus = 1; /* these may be configured by the platform code */ int bmips_smp_enabled = 1; int bmips_cpu_offset; cpumask_t bmips_booted_mask; #ifdef CONFIG_SMP /* initial $sp, $gp - used by arch/mips/kernel/bmips_vec.S */ unsigned long bmips_smp_boot_sp; unsigned long bmips_smp_boot_gp; static void bmips43xx_send_ipi_single(int cpu, unsigned int action); static void bmips5000_send_ipi_single(int cpu, unsigned int action); static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id); static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id); /* SW interrupts 0,1 are used for interprocessor signaling */ #define IPI0_IRQ (MIPS_CPU_IRQ_BASE + 0) #define IPI1_IRQ (MIPS_CPU_IRQ_BASE + 1) #define CPUNUM(cpu, shift) (((cpu) + bmips_cpu_offset) << (shift)) #define ACTION_CLR_IPI(cpu, ipi) (0x2000 | CPUNUM(cpu, 9) | ((ipi) << 8)) #define ACTION_SET_IPI(cpu, ipi) (0x3000 | CPUNUM(cpu, 9) | ((ipi) << 8)) #define ACTION_BOOT_THREAD(cpu) (0x08 | CPUNUM(cpu, 0)) static void __init bmips_smp_setup(void) { int i, cpu = 1, boot_cpu = 0; int cpu_hw_intr; switch (current_cpu_type()) { case CPU_BMIPS4350: case CPU_BMIPS4380: /* arbitration priority */ clear_c0_brcm_cmt_ctrl(0x30); /* NBK and weak order flags */ set_c0_brcm_config_0(0x30000); /* Find out if we are running on TP0 or TP1 */ boot_cpu = !!(read_c0_brcm_cmt_local() & (1 << 31)); /* * MIPS interrupts 0,1 (SW INT 0,1) cross over to the other * thread * MIPS interrupt 2 (HW INT 0) is the CPU0 L1 controller output * MIPS interrupt 3 (HW INT 1) is the CPU1 L1 controller output */ if (boot_cpu == 0) cpu_hw_intr = 0x02; else cpu_hw_intr = 0x1d; change_c0_brcm_cmt_intr(0xf8018000, (cpu_hw_intr << 27) | (0x03 << 15)); /* single core, 2 threads (2 pipelines) */ max_cpus = 2; break; case CPU_BMIPS5000: /* enable raceless SW interrupts */ set_c0_brcm_config(0x03 << 22); /* route HW interrupt 0 to CPU0, HW interrupt 1 to CPU1 */ change_c0_brcm_mode(0x1f << 27, 0x02 << 27); /* N cores, 2 threads per core */ max_cpus = (((read_c0_brcm_config() >> 6) & 0x03) + 1) << 1; /* clear any pending SW interrupts */ for (i = 0; i < max_cpus; i++) { write_c0_brcm_action(ACTION_CLR_IPI(i, 0)); write_c0_brcm_action(ACTION_CLR_IPI(i, 1)); } break; default: max_cpus = 1; } if (!bmips_smp_enabled) max_cpus = 1; /* this can be overridden by the BSP */ if (!board_ebase_setup) board_ebase_setup = &bmips_ebase_setup; __cpu_number_map[boot_cpu] = 0; __cpu_logical_map[0] = boot_cpu; for (i = 0; i < max_cpus; i++) { if (i != boot_cpu) { __cpu_number_map[i] = cpu; __cpu_logical_map[cpu] = i; cpu++; } set_cpu_possible(i, 1); set_cpu_present(i, 1); } } /* * IPI IRQ setup - runs on CPU0 */ static void bmips_prepare_cpus(unsigned int max_cpus) { irqreturn_t (*bmips_ipi_interrupt)(int irq, void *dev_id); switch (current_cpu_type()) { case CPU_BMIPS4350: case CPU_BMIPS4380: bmips_ipi_interrupt = bmips43xx_ipi_interrupt; break; case CPU_BMIPS5000: bmips_ipi_interrupt = bmips5000_ipi_interrupt; break; default: return; } if (request_irq(IPI0_IRQ, bmips_ipi_interrupt, IRQF_PERCPU, "smp_ipi0", NULL)) panic("Can't request IPI0 interrupt"); if (request_irq(IPI1_IRQ, bmips_ipi_interrupt, IRQF_PERCPU, "smp_ipi1", NULL)) panic("Can't request IPI1 interrupt"); } /* * Tell the hardware to boot CPUx - runs on CPU0 */ static void bmips_boot_secondary(int cpu, struct task_struct *idle) { bmips_smp_boot_sp = __KSTK_TOS(idle); bmips_smp_boot_gp = (unsigned long)task_thread_info(idle); mb(); /* * Initial boot sequence for secondary CPU: * bmips_reset_nmi_vec @ a000_0000 -> * bmips_smp_entry -> * plat_wired_tlb_setup (cached function call; optional) -> * start_secondary (cached jump) * * Warm restart sequence: * play_dead WAIT loop -> * bmips_smp_int_vec @ BMIPS_WARM_RESTART_VEC -> * eret to play_dead -> * bmips_secondary_reentry -> * start_secondary */ pr_info("SMP: Booting CPU%d...\n", cpu); if (cpumask_test_cpu(cpu, &bmips_booted_mask)) { switch (current_cpu_type()) { case CPU_BMIPS4350: case CPU_BMIPS4380: bmips43xx_send_ipi_single(cpu, 0); break; case CPU_BMIPS5000: bmips5000_send_ipi_single(cpu, 0); break; } } else { switch (current_cpu_type()) { case CPU_BMIPS4350: case CPU_BMIPS4380: /* Reset slave TP1 if booting from TP0 */ if (cpu_logical_map(cpu) == 1) set_c0_brcm_cmt_ctrl(0x01); break; case CPU_BMIPS5000: if (cpu & 0x01) write_c0_brcm_action(ACTION_BOOT_THREAD(cpu)); else { /* * core N thread 0 was already booted; just * pulse the NMI line */ bmips_write_zscm_reg(0x210, 0xc0000000); udelay(10); bmips_write_zscm_reg(0x210, 0x00); } break; } cpumask_set_cpu(cpu, &bmips_booted_mask); } } /* * Early setup - runs on secondary CPU after cache probe */ static void bmips_init_secondary(void) { /* move NMI vector to kseg0, in case XKS01 is enabled */ void __iomem *cbr; unsigned long old_vec; unsigned long relo_vector; int boot_cpu; switch (current_cpu_type()) { case CPU_BMIPS4350: case CPU_BMIPS4380: cbr = BMIPS_GET_CBR(); boot_cpu = !!(read_c0_brcm_cmt_local() & (1 << 31)); relo_vector = boot_cpu ? BMIPS_RELO_VECTOR_CONTROL_0 : BMIPS_RELO_VECTOR_CONTROL_1; old_vec = __raw_readl(cbr + relo_vector); __raw_writel(old_vec & ~0x20000000, cbr + relo_vector); clear_c0_cause(smp_processor_id() ? C_SW1 : C_SW0); break; case CPU_BMIPS5000: write_c0_brcm_bootvec(read_c0_brcm_bootvec() & (smp_processor_id() & 0x01 ? ~0x20000000 : ~0x2000)); write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), 0)); break; } } /* * Late setup - runs on secondary CPU before entering the idle loop */ static void bmips_smp_finish(void) { pr_info("SMP: CPU%d is running\n", smp_processor_id()); /* make sure there won't be a timer interrupt for a little while */ write_c0_compare(read_c0_count() + mips_hpt_frequency / HZ); irq_enable_hazard(); set_c0_status(IE_SW0 | IE_SW1 | IE_IRQ1 | IE_IRQ5 | ST0_IE); irq_enable_hazard(); } /* * Runs on CPU0 after all CPUs have been booted */ static void bmips_cpus_done(void) { } /* * BMIPS5000 raceless IPIs * * Each CPU has two inbound SW IRQs which are independent of all other CPUs. * IPI0 is used for SMP_RESCHEDULE_YOURSELF * IPI1 is used for SMP_CALL_FUNCTION */ static void bmips5000_send_ipi_single(int cpu, unsigned int action) { write_c0_brcm_action(ACTION_SET_IPI(cpu, action == SMP_CALL_FUNCTION)); } static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id) { int action = irq - IPI0_IRQ; write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), action)); if (action == 0) scheduler_ipi(); else smp_call_function_interrupt(); return IRQ_HANDLED; } static void bmips5000_send_ipi_mask(const struct cpumask *mask, unsigned int action) { unsigned int i; for_each_cpu(i, mask) bmips5000_send_ipi_single(i, action); } /* * BMIPS43xx racey IPIs * * We use one inbound SW IRQ for each CPU. * * A spinlock must be held in order to keep CPUx from accidentally clearing * an incoming IPI when it writes CP0 CAUSE to raise an IPI on CPUy. The * same spinlock is used to protect the action masks. */ static DEFINE_SPINLOCK(ipi_lock); static DEFINE_PER_CPU(int, ipi_action_mask); static void bmips43xx_send_ipi_single(int cpu, unsigned int action) { unsigned long flags; spin_lock_irqsave(&ipi_lock, flags); set_c0_cause(cpu ? C_SW1 : C_SW0); per_cpu(ipi_action_mask, cpu) |= action; irq_enable_hazard(); spin_unlock_irqrestore(&ipi_lock, flags); } static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id) { unsigned long flags; int action, cpu = irq - IPI0_IRQ; spin_lock_irqsave(&ipi_lock, flags); action = __get_cpu_var(ipi_action_mask); per_cpu(ipi_action_mask, cpu) = 0; clear_c0_cause(cpu ? C_SW1 : C_SW0); spin_unlock_irqrestore(&ipi_lock, flags); if (action & SMP_RESCHEDULE_YOURSELF) scheduler_ipi(); if (action & SMP_CALL_FUNCTION) smp_call_function_interrupt(); return IRQ_HANDLED; } static void bmips43xx_send_ipi_mask(const struct cpumask *mask, unsigned int action) { unsigned int i; for_each_cpu(i, mask) bmips43xx_send_ipi_single(i, action); } #ifdef CONFIG_HOTPLUG_CPU static int bmips_cpu_disable(void) { unsigned int cpu = smp_processor_id(); if (cpu == 0) return -EBUSY; pr_info("SMP: CPU%d is offline\n", cpu); set_cpu_online(cpu, false); cpu_clear(cpu, cpu_callin_map); local_flush_tlb_all(); local_flush_icache_range(0, ~0); return 0; } static void bmips_cpu_die(unsigned int cpu) { } void __ref play_dead(void) { idle_task_exit(); /* flush data cache */ _dma_cache_wback_inv(0, ~0); /* * Wakeup is on SW0 or SW1; disable everything else * Use BEV !IV (BMIPS_WARM_RESTART_VEC) to avoid the regular Linux * IRQ handlers; this clears ST0_IE and returns immediately. */ clear_c0_cause(CAUSEF_IV | C_SW0 | C_SW1); change_c0_status(IE_IRQ5 | IE_IRQ1 | IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV, IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV); irq_disable_hazard(); /* * wait for SW interrupt from bmips_boot_secondary(), then jump * back to start_secondary() */ __asm__ __volatile__( " wait\n" " j bmips_secondary_reentry\n" : : : "memory"); } #endif /* CONFIG_HOTPLUG_CPU */ struct plat_smp_ops bmips43xx_smp_ops = { .smp_setup = bmips_smp_setup, .prepare_cpus = bmips_prepare_cpus, .boot_secondary = bmips_boot_secondary, .smp_finish = bmips_smp_finish, .init_secondary = bmips_init_secondary, .cpus_done = bmips_cpus_done, .send_ipi_single = bmips43xx_send_ipi_single, .send_ipi_mask = bmips43xx_send_ipi_mask, #ifdef CONFIG_HOTPLUG_CPU .cpu_disable = bmips_cpu_disable, .cpu_die = bmips_cpu_die, #endif }; struct plat_smp_ops bmips5000_smp_ops = { .smp_setup = bmips_smp_setup, .prepare_cpus = bmips_prepare_cpus, .boot_secondary = bmips_boot_secondary, .smp_finish = bmips_smp_finish, .init_secondary = bmips_init_secondary, .cpus_done = bmips_cpus_done, .send_ipi_single = bmips5000_send_ipi_single, .send_ipi_mask = bmips5000_send_ipi_mask, #ifdef CONFIG_HOTPLUG_CPU .cpu_disable = bmips_cpu_disable, .cpu_die = bmips_cpu_die, #endif }; #endif /* CONFIG_SMP */ /*********************************************************************** * BMIPS vector relocation * This is primarily used for SMP boot, but it is applicable to some * UP BMIPS systems as well. ***********************************************************************/ static void bmips_wr_vec(unsigned long dst, char *start, char *end) { memcpy((void *)dst, start, end - start); dma_cache_wback((unsigned long)start, end - start); local_flush_icache_range(dst, dst + (end - start)); instruction_hazard(); } static inline void bmips_nmi_handler_setup(void) { bmips_wr_vec(BMIPS_NMI_RESET_VEC, &bmips_reset_nmi_vec, &bmips_reset_nmi_vec_end); bmips_wr_vec(BMIPS_WARM_RESTART_VEC, &bmips_smp_int_vec, &bmips_smp_int_vec_end); } void bmips_ebase_setup(void) { unsigned long new_ebase = ebase; void __iomem __maybe_unused *cbr; BUG_ON(ebase != CKSEG0); switch (current_cpu_type()) { case CPU_BMIPS4350: /* * BMIPS4350 cannot relocate the normal vectors, but it * can relocate the BEV=1 vectors. So CPU1 starts up at * the relocated BEV=1, IV=0 general exception vector @ * 0xa000_0380. * * set_uncached_handler() is used here because: * - CPU1 will run this from uncached space * - None of the cacheflush functions are set up yet */ set_uncached_handler(BMIPS_WARM_RESTART_VEC - CKSEG0, &bmips_smp_int_vec, 0x80); __sync(); return; case CPU_BMIPS4380: /* * 0x8000_0000: reset/NMI (initially in kseg1) * 0x8000_0400: normal vectors */ new_ebase = 0x80000400; cbr = BMIPS_GET_CBR(); __raw_writel(0x80080800, cbr + BMIPS_RELO_VECTOR_CONTROL_0); __raw_writel(0xa0080800, cbr + BMIPS_RELO_VECTOR_CONTROL_1); break; case CPU_BMIPS5000: /* * 0x8000_0000: reset/NMI (initially in kseg1) * 0x8000_1000: normal vectors */ new_ebase = 0x80001000; write_c0_brcm_bootvec(0xa0088008); write_c0_ebase(new_ebase); if (max_cpus > 2) bmips_write_zscm_reg(0xa0, 0xa008a008); break; default: return; } board_nmi_handler_setup = &bmips_nmi_handler_setup; ebase = new_ebase; } asmlinkage void __weak plat_wired_tlb_setup(void) { /* * Called when starting/restarting a secondary CPU. * Kernel stacks and other important data might only be accessible * once the wired entries are present. */ }