|  | /* | 
|  | * 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/init.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 bmips_send_ipi_single(int cpu, unsigned int action); | 
|  | static irqreturn_t bmips_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; | 
|  |  | 
|  | #if defined(CONFIG_CPU_BMIPS4350) || defined(CONFIG_CPU_BMIPS4380) | 
|  | /* arbitration priority */ | 
|  | clear_c0_brcm_cmt_ctrl(0x30); | 
|  |  | 
|  | /* NBK and weak order flags */ | 
|  | set_c0_brcm_config_0(0x30000); | 
|  |  | 
|  | /* | 
|  | * 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 | 
|  | */ | 
|  | change_c0_brcm_cmt_intr(0xf8018000, | 
|  | (0x02 << 27) | (0x03 << 15)); | 
|  |  | 
|  | /* single core, 2 threads (2 pipelines) */ | 
|  | max_cpus = 2; | 
|  | #elif defined(CONFIG_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)); | 
|  | } | 
|  | #endif | 
|  |  | 
|  | if (!bmips_smp_enabled) | 
|  | max_cpus = 1; | 
|  |  | 
|  | /* this can be overridden by the BSP */ | 
|  | if (!board_ebase_setup) | 
|  | board_ebase_setup = &bmips_ebase_setup; | 
|  |  | 
|  | for (i = 0; i < max_cpus; i++) { | 
|  | __cpu_number_map[i] = 1; | 
|  | __cpu_logical_map[i] = 1; | 
|  | 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) | 
|  | { | 
|  | if (request_irq(IPI0_IRQ, bmips_ipi_interrupt, IRQF_PERCPU, | 
|  | "smp_ipi0", NULL)) | 
|  | panic("Can't request IPI0 interrupt\n"); | 
|  | if (request_irq(IPI1_IRQ, bmips_ipi_interrupt, IRQF_PERCPU, | 
|  | "smp_ipi1", NULL)) | 
|  | panic("Can't request IPI1 interrupt\n"); | 
|  | } | 
|  |  | 
|  | /* | 
|  | * 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)) | 
|  | bmips_send_ipi_single(cpu, 0); | 
|  | else { | 
|  | #if defined(CONFIG_CPU_BMIPS4350) || defined(CONFIG_CPU_BMIPS4380) | 
|  | set_c0_brcm_cmt_ctrl(0x01); | 
|  | #elif defined(CONFIG_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); | 
|  | } | 
|  | #endif | 
|  | 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 */ | 
|  |  | 
|  | #if defined(CONFIG_CPU_BMIPS4350) || defined(CONFIG_CPU_BMIPS4380) | 
|  | void __iomem *cbr = BMIPS_GET_CBR(); | 
|  | unsigned long old_vec; | 
|  |  | 
|  | old_vec = __raw_readl(cbr + BMIPS_RELO_VECTOR_CONTROL_1); | 
|  | __raw_writel(old_vec & ~0x20000000, cbr + BMIPS_RELO_VECTOR_CONTROL_1); | 
|  |  | 
|  | clear_c0_cause(smp_processor_id() ? C_SW1 : C_SW0); | 
|  | #elif defined(CONFIG_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)); | 
|  | #endif | 
|  |  | 
|  | /* 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(); | 
|  | } | 
|  |  | 
|  | /* | 
|  | * 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()); | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Runs on CPU0 after all CPUs have been booted | 
|  | */ | 
|  | static void bmips_cpus_done(void) | 
|  | { | 
|  | } | 
|  |  | 
|  | #if defined(CONFIG_CPU_BMIPS5000) | 
|  |  | 
|  | /* | 
|  | * 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 bmips_send_ipi_single(int cpu, unsigned int action) | 
|  | { | 
|  | write_c0_brcm_action(ACTION_SET_IPI(cpu, action == SMP_CALL_FUNCTION)); | 
|  | } | 
|  |  | 
|  | static irqreturn_t bmips_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; | 
|  | } | 
|  |  | 
|  | #else | 
|  |  | 
|  | /* | 
|  | * 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 bmips_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 bmips_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; | 
|  | } | 
|  |  | 
|  | #endif /* BMIPS type */ | 
|  |  | 
|  | static void bmips_send_ipi_mask(const struct cpumask *mask, | 
|  | unsigned int action) | 
|  | { | 
|  | unsigned int i; | 
|  |  | 
|  | for_each_cpu(i, mask) | 
|  | bmips_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 bmips_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	= bmips_send_ipi_single, | 
|  | .send_ipi_mask		= bmips_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 __cpuinit 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 __cpuinit 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 __cpuinit bmips_ebase_setup(void) | 
|  | { | 
|  | unsigned long new_ebase = ebase; | 
|  | void __iomem __maybe_unused *cbr; | 
|  |  | 
|  | BUG_ON(ebase != CKSEG0); | 
|  |  | 
|  | #if defined(CONFIG_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; | 
|  | #elif defined(CONFIG_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); | 
|  | #elif defined(CONFIG_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); | 
|  | #else | 
|  | return; | 
|  | #endif | 
|  | 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. | 
|  | */ | 
|  | } |