From mboxrd@z Thu Jan 1 00:00:00 1970 From: nicolas.pitre@linaro.org (Nicolas Pitre) Date: Fri, 07 Jun 2013 02:39:11 -0400 Subject: [PATCH 1/2] ARM: vexpress/TC2: basic PM support In-Reply-To: <1370587152-4630-1-git-send-email-nicolas.pitre@linaro.org> References: <1370587152-4630-1-git-send-email-nicolas.pitre@linaro.org> Message-ID: <1370587152-4630-2-git-send-email-nicolas.pitre@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org This is the MCPM backend for the Virtual Express A15x2 A7x3 CoreTile aka TC2. This provides cluster management for SMP secondary boot and CPU hotplug. Signed-off-by: Nicolas Pitre --- arch/arm/mach-vexpress/Kconfig | 9 ++ arch/arm/mach-vexpress/Makefile | 1 + arch/arm/mach-vexpress/tc2_pm.c | 243 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 253 insertions(+) create mode 100644 arch/arm/mach-vexpress/tc2_pm.c diff --git a/arch/arm/mach-vexpress/Kconfig b/arch/arm/mach-vexpress/Kconfig index b8bbabec63..e7a825d7df 100644 --- a/arch/arm/mach-vexpress/Kconfig +++ b/arch/arm/mach-vexpress/Kconfig @@ -66,4 +66,13 @@ config ARCH_VEXPRESS_DCSCB This is needed to provide CPU and cluster power management on RTSM implementing big.LITTLE. +config ARCH_VEXPRESS_TC2 + bool "Versatile Express TC2 power management" + depends on MCPM + select VEXPRESS_SPC + select ARM_CCI + help + Support for CPU and cluster power management on Versatile Express + with a TC2 (A15x2 A7x3) big.LITTLE core tile. + endmenu diff --git a/arch/arm/mach-vexpress/Makefile b/arch/arm/mach-vexpress/Makefile index 48ba89a814..b1cf227fa5 100644 --- a/arch/arm/mach-vexpress/Makefile +++ b/arch/arm/mach-vexpress/Makefile @@ -7,5 +7,6 @@ ccflags-$(CONFIG_ARCH_MULTIPLATFORM) := -I$(srctree)/$(src)/include \ obj-y := v2m.o obj-$(CONFIG_ARCH_VEXPRESS_CA9X4) += ct-ca9x4.o obj-$(CONFIG_ARCH_VEXPRESS_DCSCB) += dcscb.o dcscb_setup.o +obj-$(CONFIG_ARCH_VEXPRESS_TC2) += tc2_pm.o obj-$(CONFIG_SMP) += platsmp.o obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c new file mode 100644 index 0000000000..a3ea524372 --- /dev/null +++ b/arch/arm/mach-vexpress/tc2_pm.c @@ -0,0 +1,243 @@ +/* + * arch/arm/mach-vexpress/tc2_pm.c - TC2 power management support + * + * Created by: Nicolas Pitre, October 2012 + * Copyright: (C) 2012-2013 Linaro Limited + * + * Some portions of this file were originally written by Achin Gupta + * Copyright: (C) 2012 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +#include + +#include +#include + +/* + * We can't use regular spinlocks. In the switcher case, it is possible + * for an outbound CPU to call power_down() after its inbound counterpart + * is already live using the same logical CPU number which trips lockdep + * debugging. + */ +static arch_spinlock_t tc2_pm_lock = __ARCH_SPIN_LOCK_UNLOCKED; + +static int tc2_pm_use_count[3][2]; + +static int tc2_pm_power_up(unsigned int cpu, unsigned int cluster) +{ + pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); + if (cluster >= 2 || cpu >= vexpress_spc_get_nb_cpus(cluster)) + return -EINVAL; + + /* + * Since this is called with IRQs enabled, and no arch_spin_lock_irq + * variant exists, we need to disable IRQs manually here. + */ + local_irq_disable(); + arch_spin_lock(&tc2_pm_lock); + + if (!tc2_pm_use_count[0][cluster] && + !tc2_pm_use_count[1][cluster] && + !tc2_pm_use_count[2][cluster]) + vexpress_spc_powerdown_enable(cluster, 0); + + tc2_pm_use_count[cpu][cluster]++; + if (tc2_pm_use_count[cpu][cluster] == 1) { + vexpress_spc_write_resume_reg(cluster, cpu, + virt_to_phys(mcpm_entry_point)); + vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 1); + } else if (tc2_pm_use_count[cpu][cluster] != 2) { + /* + * The only possible values are: + * 0 = CPU down + * 1 = CPU (still) up + * 2 = CPU requested to be up before it had a chance + * to actually make itself down. + * Any other value is a bug. + */ + BUG(); + } + + arch_spin_unlock(&tc2_pm_lock); + local_irq_enable(); + + return 0; +} + +static void tc2_pm_power_down(void) +{ + unsigned int mpidr, cpu, cluster; + bool last_man = false, skip_wfi = false; + + mpidr = read_cpuid_mpidr(); + cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); + cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); + + pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); + BUG_ON(cluster >= 2 || cpu >= vexpress_spc_get_nb_cpus(cluster)); + + __mcpm_cpu_going_down(cpu, cluster); + + arch_spin_lock(&tc2_pm_lock); + BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP); + tc2_pm_use_count[cpu][cluster]--; + if (tc2_pm_use_count[cpu][cluster] == 0) { + vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 1); + if (!tc2_pm_use_count[0][cluster] && + !tc2_pm_use_count[1][cluster] && + !tc2_pm_use_count[2][cluster]) { + vexpress_spc_powerdown_enable(cluster, 1); + vexpress_spc_set_global_wakeup_intr(1); + last_man = true; + } + } else if (tc2_pm_use_count[cpu][cluster] == 1) { + /* + * A power_up request went ahead of us. + * Even if we do not want to shut this CPU down, + * the caller expects a certain state as if the WFI + * was aborted. So let's continue with cache cleaning. + */ + skip_wfi = true; + } else + BUG(); + + if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) { + arch_spin_unlock(&tc2_pm_lock); + + set_cr(get_cr() & ~CR_C); + flush_cache_all(); + asm volatile ("clrex"); + set_auxcr(get_auxcr() & ~(1 << 6)); + + cci_disable_port_by_cpu(mpidr); + + /* + * Ensure that both C & I bits are disabled in the SCTLR + * before disabling ACE snoops. This ensures that no + * coherency traffic will originate from this cpu after + * ACE snoops are turned off. + */ + cpu_proc_fin(); + + __mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN); + } else { + /* + * If last man then undo any setup done previously. + */ + if (last_man) { + vexpress_spc_powerdown_enable(cluster, 0); + vexpress_spc_set_global_wakeup_intr(0); + } + + arch_spin_unlock(&tc2_pm_lock); + + set_cr(get_cr() & ~CR_C); + flush_cache_louis(); + asm volatile ("clrex"); + set_auxcr(get_auxcr() & ~(1 << 6)); + } + + __mcpm_cpu_down(cpu, cluster); + + /* Now we are prepared for power-down, do it: */ + if (!skip_wfi) + wfi(); + + /* Not dead@this point? Let our caller cope. */ +} + +static void tc2_pm_powered_up(void) +{ + unsigned int mpidr, cpu, cluster; + unsigned long flags; + + mpidr = read_cpuid_mpidr(); + cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); + cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); + + pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); + BUG_ON(cluster >= 2 || cpu >= vexpress_spc_get_nb_cpus(cluster)); + + local_irq_save(flags); + arch_spin_lock(&tc2_pm_lock); + + if (!tc2_pm_use_count[0][cluster] && + !tc2_pm_use_count[1][cluster] && + !tc2_pm_use_count[2][cluster]) { + vexpress_spc_powerdown_enable(cluster, 0); + vexpress_spc_set_global_wakeup_intr(0); + } + + if (!tc2_pm_use_count[cpu][cluster]) + tc2_pm_use_count[cpu][cluster] = 1; + + vexpress_spc_set_cpu_wakeup_irq(cpu, cluster, 0); + vexpress_spc_write_resume_reg(cluster, cpu, 0); + + arch_spin_unlock(&tc2_pm_lock); + local_irq_restore(flags); +} + +static const struct mcpm_platform_ops tc2_pm_power_ops = { + .power_up = tc2_pm_power_up, + .power_down = tc2_pm_power_down, + .powered_up = tc2_pm_powered_up, +}; + +static void __init tc2_pm_usage_count_init(void) +{ + unsigned int mpidr, cpu, cluster; + + mpidr = read_cpuid_mpidr(); + cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); + cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); + + pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster); + BUG_ON(cpu >= 3 || cluster >= 2); + tc2_pm_use_count[cpu][cluster] = 1; +} + +/* + * Enable cluster-level coherency, in preparation for turning on the MMU. + */ +static void __naked tc2_pm_power_up_setup(unsigned int affinity_level) +{ + asm volatile (" \n" +" cmp r0, #1 \n" +" beq cci_enable_port_for_self \n" +" bx lr "); +} + +static int __init tc2_pm_init(void) +{ + int ret; + + if (!vexpress_spc_check_loaded()) + return -ENODEV; + + tc2_pm_usage_count_init(); + + ret = mcpm_platform_register(&tc2_pm_power_ops); + if (!ret) + ret = mcpm_sync_init(tc2_pm_power_up_setup); + if (!ret) + pr_info("TC2 power management initialized\n"); + return ret; +} + +early_initcall(tc2_pm_init); -- 1.8.1.2