[v3,RESEND,2/5] ARM: add SMP support for Broadcom mobile SoCs

Message ID	1400176691-26058-3-git-send-email-elder@linaro.org
State	New
Headers	show Return-Path: <patchwork-forward+bncBDD6VEWXZUOBBP4A2SNQKGQEZH26ZAY@linaro.org> MIME-Version: 1.0 Received-SPF: pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.128.180 as permitted sender) client-ip=209.85.128.180; Received-SPF: none (google.com: linux-kernel-owner@vger.kernel.org does not designate permitted sender hosts) client-ip=209.132.180.67; From: Alex Elder <elder@linaro.org> To: mporter@linaro.org, bcm@fixthebug.org, linux@arm.linux.org.uk, devicetree@vger.kernel.org, arnd@arndb.de, sboyd@codeaurora.org Cc: bcm-kernel-feedback-list@broadcom.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 RESEND 2/5] ARM: add SMP support for Broadcom mobile SoCs Date: Thu, 15 May 2014 12:58:08 -0500 Message-Id: <1400176691-26058-3-git-send-email-elder@linaro.org> In-Reply-To: <1400176691-26058-1-git-send-email-elder@linaro.org> References: <1400176691-26058-1-git-send-email-elder@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: list Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org

diff --git a/arch/arm/mach-bcm/Kconfig b/arch/arm/mach-bcm/Kconfig index 5f5740f..336fc6f 100644 --- a/arch/arm/mach-bcm/Kconfig +++ b/arch/arm/mach-bcm/Kconfig @@ -14,7 +14,6 @@ config ARCH_BCM_MOBILE depends on MMU select ARCH_REQUIRE_GPIOLIB select ARM_ERRATA_754322 - select ARM_ERRATA_764369 if SMP select ARM_GIC select GPIO_BCM_KONA select TICK_ONESHOT @@ -31,18 +30,31 @@ menu "Broadcom Mobile SoC Selection" config ARCH_BCM_281XX bool "Broadcom BCM281XX SoC family" default y + select HAVE_SMP help - Enable support for the the BCM281XX family, which includes + Enable support for the BCM281XX family, which includes BCM11130, BCM11140, BCM11351, BCM28145 and BCM28155 variants. config ARCH_BCM_21664 bool "Broadcom BCM21664 SoC family" default y + select HAVE_SMP help - Enable support for the the BCM21664 family, which includes + Enable support for the BCM21664 family, which includes BCM21663 and BCM21664 variants. +config ARCH_BCM_MOBILE_SMP + bool "Broadcom mobile SoC SMP support" + depends on (ARCH_BCM_281XX || ARCH_BCM_21664) && SMP + default y + select HAVE_ARM_SCU + select ARM_ERRATA_764369 + help + SMP support for the BCM281XX and BCM21664 SoC families. + Provided as an option so SMP support for SoCs of this type + can be disabled for an SMP-enabled kernel. + endmenu endif diff --git a/arch/arm/mach-bcm/Makefile b/arch/arm/mach-bcm/Makefile index 7fb9b04..08c01a9 100644 --- a/arch/arm/mach-bcm/Makefile +++ b/arch/arm/mach-bcm/Makefile @@ -16,6 +16,9 @@ obj-$(CONFIG_ARCH_BCM_281XX) += board_bcm281xx.o # BCM21664 obj-$(CONFIG_ARCH_BCM_21664) += board_bcm21664.o +# BCM281XX and BCM21664 SMP support +obj-$(CONFIG_ARCH_BCM_MOBILE_SMP) += platsmp.o + # BCM281XX and BCM21664 L2 cache control obj-$(CONFIG_ARCH_BCM_MOBILE) += bcm_kona_smc.o bcm_kona_smc_asm.o kona.o plus_sec := $(call as-instr,.arch_extension sec,+sec) diff --git a/arch/arm/mach-bcm/platsmp.c b/arch/arm/mach-bcm/platsmp.c new file mode 100644 index 0000000..a85875b --- /dev/null +++ b/arch/arm/mach-bcm/platsmp.c @@ -0,0 +1,201 @@ +/* + * Copyright (C) 2014 Broadcom Corporation + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation version 2. + * + * This program is distributed "as is" WITHOUT ANY WARRANTY of any + * kind, whether express or implied; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/init.h> +#include <linux/errno.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/sched.h> + +#include <asm/smp.h> +#include <asm/smp_plat.h> +#include <asm/smp_scu.h> + +/* Size of mapped Cortex A9 SCU address space */ +#define CORTEX_A9_SCU_SIZE 0x58 + +#define SECONDARY_TIMEOUT_NS NSEC_PER_MSEC /* 1 msec (in nanoseconds) */ +#define BOOT_ADDR_CPUID_MASK 0x3 + +/* Name of device node property defining secondary boot register location */ +#define OF_SECONDARY_BOOT "secondary-boot-reg" + +/* I/O address of register used to coordinate secondary core startup */ +static u32 secondary_boot; + +/* + * Enable the Cortex A9 Snoop Control Unit + * + * By the time this is called we already know there are multiple + * cores present. We assume we're running on a Cortex A9 processor, + * so any trouble getting the base address register or getting the + * SCU base is a problem. + * + * Return 0 if successful or an error code otherwise. + */ +static int __init scu_a9_enable(void) +{ + unsigned long config_base; + void __iomem *scu_base; + + if (!scu_a9_has_base()) { + pr_err("no configuration base address register!\n"); + return -ENXIO; + } + + /* Config base address register value is zero for uniprocessor */ + config_base = scu_a9_get_base(); + if (!config_base) { + pr_err("hardware reports only one core\n"); + return -ENOENT; + } + + scu_base = ioremap((phys_addr_t)config_base, CORTEX_A9_SCU_SIZE); + if (!scu_base) { + pr_err("failed to remap config base (%lu/%u) for SCU\n", + config_base, CORTEX_A9_SCU_SIZE); + return -ENOMEM; + } + + scu_enable(scu_base); + + iounmap(scu_base); /* That's the last we'll need of this */ + + return 0; +} + +static void __init bcm_smp_prepare_cpus(unsigned int max_cpus) +{ + static cpumask_t only_cpu_0 = { CPU_BITS_CPU0 }; + struct device_node *node; + int ret; + + BUG_ON(secondary_boot); /* We're called only once */ + + /* + * This function is only called via smp_ops->smp_prepare_cpu(). + * That only happens if a "/cpus" device tree node exists + * and has an "enable-method" property that selects the SMP + * operations defined herein. + */ + node = of_find_node_by_path("/cpus"); + BUG_ON(!node); + + /* + * Our secondary enable method requires a "secondary-boot-reg" + * property to specify a register address used to request the + * ROM code boot a secondary code. If we have any trouble + * getting this we fall back to uniprocessor mode. + */ + if (of_property_read_u32(node, OF_SECONDARY_BOOT, &secondary_boot)) { + pr_err("%s: missing/invalid " OF_SECONDARY_BOOT " property\n", + node->name); + ret = -ENOENT; /* Arrange to disable SMP */ + goto out; + } + + /* + * Enable the SCU on Cortex A9 based SoCs. If -ENOENT is + * returned, the SoC reported a uniprocessor configuration. + * We bail on any other error. + */ + ret = scu_a9_enable(); +out: + of_node_put(node); + if (ret) { + /* Update the CPU present map to reflect uniprocessor mode */ + BUG_ON(ret != -ENOENT); + pr_warn("disabling SMP\n"); + init_cpu_present(&only_cpu_0); + } +} + +/* + * The ROM code has the secondary cores looping, waiting for an event. + * When an event occurs each core examines the bottom two bits of the + * secondary boot register. When a core finds those bits contain its + * own core id, it performs initialization, including computing its boot + * address by clearing the boot register value's bottom two bits. The + * core signals that it is beginning its execution by writing its boot + * address back to the secondary boot register, and finally jumps to + * that address. + * + * So to start a core executing we need to: + * - Encode the (hardware) CPU id with the bottom bits of the secondary + * start address. + * - Write that value into the secondary boot register. + * - Generate an event to wake up the secondary CPU(s). + * - Wait for the secondary boot register to be re-written, which + * indicates the secondary core has started. + */ +static int bcm_boot_secondary(unsigned int cpu, struct task_struct *idle) +{ + void __iomem *boot_reg; + phys_addr_t boot_func; + u64 start_clock; + u32 cpu_id; + u32 boot_val; + bool timeout = false; + + cpu_id = cpu_logical_map(cpu); + if (cpu_id & ~BOOT_ADDR_CPUID_MASK) { + pr_err("bad cpu id (%u > %u)\n", cpu_id, BOOT_ADDR_CPUID_MASK); + return -EINVAL; + } + + if (!secondary_boot) { + pr_err("required secondary boot register not specified\n"); + return -EINVAL; + } + + boot_reg = ioremap_nocache((phys_addr_t)secondary_boot, sizeof(u32)); + if (!boot_reg) { + pr_err("unable to map boot register for cpu %u\n", cpu_id); + return -ENOSYS; + } + + /* + * Secondary cores will start in secondary_startup(), + * defined in "arch/arm/kernel/head.S" + */ + boot_func = virt_to_phys(secondary_startup); + BUG_ON(boot_func & BOOT_ADDR_CPUID_MASK); + BUG_ON(boot_func > (phys_addr_t)U32_MAX); + + /* The core to start is encoded in the low bits */ + boot_val = (u32)boot_func | cpu_id; + writel_relaxed(boot_val, boot_reg); + + sev(); + + /* The low bits will be cleared once the core has started */ + start_clock = local_clock(); + while (!timeout && readl_relaxed(boot_reg) == boot_val) + timeout = local_clock() - start_clock > SECONDARY_TIMEOUT_NS; + + iounmap(boot_reg); + + if (!timeout) + return 0; + + pr_err("timeout waiting for cpu %u to start\n", cpu_id); + + return -ENOSYS; +} + +static struct smp_operations bcm_smp_ops __initdata = { + .smp_prepare_cpus = bcm_smp_prepare_cpus, + .smp_boot_secondary = bcm_boot_secondary, +}; +CPU_METHOD_OF_DECLARE(bcm_smp_bcm281xx, "brcm,bcm11351-cpu-method", + &bcm_smp_ops);

[v3,RESEND,2/5] ARM: add SMP support for Broadcom mobile SoCs

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