arch/arm/mach-bcm/platsmp.c - linux - Git at Google

 /*
  * Copyright (C) 2014-2015 Broadcom Corporation
  * Copyright 2014 Linaro Limited
  *
  * 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/cpumask.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/irqchip/irq-bcm2836.h>
 #include <linux/jiffies.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/sched.h>
 #include <linux/sched/clock.h>
 #include <linux/smp.h>

 #include <asm/cacheflush.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"
 #define MPIDR_CPUID_BITMASK	0x3

 /*
  * 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 u32 secondary_boot_addr_for(unsigned int cpu)
 {
 	u32 secondary_boot_addr = 0;
 	struct device_node *cpu_node = of_get_cpu_node(cpu, NULL);

         if (!cpu_node) {
 		pr_err("Failed to find device tree node for CPU%u\n", cpu);
 		return 0;
 	}

 	if (of_property_read_u32(cpu_node,
 				 OF_SECONDARY_BOOT,
 				 &secondary_boot_addr))
 		pr_err("required secondary boot register not specified for CPU%u\n",
 			cpu);

 	of_node_put(cpu_node);

 	return secondary_boot_addr;
 }

 static int nsp_write_lut(unsigned int cpu)
 {
 	void __iomem *sku_rom_lut;
 	phys_addr_t secondary_startup_phy;
 	const u32 secondary_boot_addr = secondary_boot_addr_for(cpu);

 	if (!secondary_boot_addr)
 		return -EINVAL;

 	sku_rom_lut = ioremap_nocache((phys_addr_t)secondary_boot_addr,
 				      sizeof(phys_addr_t));
 	if (!sku_rom_lut) {
 		pr_warn("unable to ioremap SKU-ROM LUT register for cpu %u\n", cpu);
 		return -ENOMEM;
 	}

 	secondary_startup_phy = __pa_symbol(secondary_startup);
 	BUG_ON(secondary_startup_phy > (phys_addr_t)U32_MAX);

 	writel_relaxed(secondary_startup_phy, sku_rom_lut);

 	/* Ensure the write is visible to the secondary core */
 	smp_wmb();

 	iounmap(sku_rom_lut);

 	return 0;
 }

 static void __init bcm_smp_prepare_cpus(unsigned int max_cpus)
 {
 	const cpumask_t only_cpu_0 = { CPU_BITS_CPU0 };

 	/* Enable the SCU on Cortex A9 based SoCs */
 	if (scu_a9_enable()) {
 		/* Update the CPU present map to reflect uniprocessor mode */
 		pr_warn("failed to enable A9 SCU - 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 kona_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;
 	const u32 secondary_boot_addr = secondary_boot_addr_for(cpu);

 	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_addr)
 		return -EINVAL;

 	boot_reg = ioremap_nocache((phys_addr_t)secondary_boot_addr,
 				   sizeof(phys_addr_t));
 	if (!boot_reg) {
 		pr_err("unable to map boot register for cpu %u\n", cpu_id);
 		return -ENOMEM;
 	}

 	/*
 	 * Secondary cores will start in secondary_startup(),
 	 * defined in "arch/arm/kernel/head.S"
 	 */
 	boot_func = __pa_symbol(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 -ENXIO;
 }

 /* Cluster Dormant Control command to bring CPU into a running state */
 #define CDC_CMD			6
 #define CDC_CMD_OFFSET		0
 #define CDC_CMD_REG(cpu)	(CDC_CMD_OFFSET + 4*(cpu))

 /*
  * BCM23550 has a Cluster Dormant Control block that keeps the core in
  * idle state. A command needs to be sent to the block to bring the CPU
  * into running state.
  */
 static int bcm23550_boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
 	void __iomem *cdc_base;
 	struct device_node *dn;
 	char *name;
 	int ret;

 	/* Make sure a CDC node exists before booting the
 	 * secondary core.
 	 */
 	name = "brcm,bcm23550-cdc";
 	dn = of_find_compatible_node(NULL, NULL, name);
 	if (!dn) {
 		pr_err("unable to find cdc node\n");
 		return -ENODEV;
 	}

 	cdc_base = of_iomap(dn, 0);
 	of_node_put(dn);

 	if (!cdc_base) {
 		pr_err("unable to remap cdc base register\n");
 		return -ENOMEM;
 	}

 	/* Boot the secondary core */
 	ret = kona_boot_secondary(cpu, idle);
 	if (ret)
 		goto out;

 	/* Bring this CPU to RUN state so that nIRQ nFIQ
 	 * signals are unblocked.
 	 */
 	writel_relaxed(CDC_CMD, cdc_base + CDC_CMD_REG(cpu));

 out:
 	iounmap(cdc_base);

 	return ret;
 }

 static int nsp_boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
 	int ret;

 	/*
 	 * After wake up, secondary core branches to the startup
 	 * address programmed at SKU ROM LUT location.
 	 */
 	ret = nsp_write_lut(cpu);
 	if (ret) {
 		pr_err("unable to write startup addr to SKU ROM LUT\n");
 		goto out;
 	}

 	/* Send a CPU wakeup interrupt to the secondary core */
 	arch_send_wakeup_ipi_mask(cpumask_of(cpu));

 out:
 	return ret;
 }

 static int bcm2836_boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
 	void __iomem *intc_base;
 	struct device_node *dn;
 	char *name;

 	name = "brcm,bcm2836-l1-intc";
 	dn = of_find_compatible_node(NULL, NULL, name);
 	if (!dn) {
 		pr_err("unable to find intc node\n");
 		return -ENODEV;
 	}

 	intc_base = of_iomap(dn, 0);
 	of_node_put(dn);

 	if (!intc_base) {
 		pr_err("unable to remap intc base register\n");
 		return -ENOMEM;
 	}

 	writel(virt_to_phys(secondary_startup),
 	       intc_base + LOCAL_MAILBOX3_SET0 + 16 * cpu);

 	dsb(sy);
 	sev();

 	iounmap(intc_base);

 	return 0;
 }

 static const struct smp_operations kona_smp_ops __initconst = {
 	.smp_prepare_cpus	= bcm_smp_prepare_cpus,
 	.smp_boot_secondary	= kona_boot_secondary,
 };
 CPU_METHOD_OF_DECLARE(bcm_smp_bcm281xx, "brcm,bcm11351-cpu-method",
 			&kona_smp_ops);

 static const struct smp_operations bcm23550_smp_ops __initconst = {
 	.smp_boot_secondary	= bcm23550_boot_secondary,
 };
 CPU_METHOD_OF_DECLARE(bcm_smp_bcm23550, "brcm,bcm23550",
 			&bcm23550_smp_ops);

 static const struct smp_operations nsp_smp_ops __initconst = {
 	.smp_prepare_cpus	= bcm_smp_prepare_cpus,
 	.smp_boot_secondary	= nsp_boot_secondary,
 };
 CPU_METHOD_OF_DECLARE(bcm_smp_nsp, "brcm,bcm-nsp-smp", &nsp_smp_ops);

 const struct smp_operations bcm2836_smp_ops __initconst = {
 	.smp_boot_secondary	= bcm2836_boot_secondary,
 };
 CPU_METHOD_OF_DECLARE(bcm_smp_bcm2836, "brcm,bcm2836-smp", &bcm2836_smp_ops);
	/*
	* Copyright (C) 2014-2015 Broadcom Corporation
	* Copyright 2014 Linaro Limited
	*
	* 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/cpumask.h>
	#include <linux/delay.h>
	#include <linux/errno.h>
	#include <linux/init.h>
	#include <linux/io.h>
	#include <linux/irqchip/irq-bcm2836.h>
	#include <linux/jiffies.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/sched.h>
	#include <linux/sched/clock.h>
	#include <linux/smp.h>

	#include <asm/cacheflush.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"
	#define MPIDR_CPUID_BITMASK 0x3

	/*
	* 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 u32 secondary_boot_addr_for(unsigned int cpu)
	{
	u32 secondary_boot_addr = 0;
	struct device_node *cpu_node = of_get_cpu_node(cpu, NULL);

	if (!cpu_node) {
	pr_err("Failed to find device tree node for CPU%u\n", cpu);
	return 0;
	}

	if (of_property_read_u32(cpu_node,
	OF_SECONDARY_BOOT,
	&secondary_boot_addr))
	pr_err("required secondary boot register not specified for CPU%u\n",
	cpu);

	of_node_put(cpu_node);

	return secondary_boot_addr;
	}

	static int nsp_write_lut(unsigned int cpu)
	{
	void __iomem *sku_rom_lut;
	phys_addr_t secondary_startup_phy;
	const u32 secondary_boot_addr = secondary_boot_addr_for(cpu);

	if (!secondary_boot_addr)
	return -EINVAL;

	sku_rom_lut = ioremap_nocache((phys_addr_t)secondary_boot_addr,
	sizeof(phys_addr_t));
	if (!sku_rom_lut) {
	pr_warn("unable to ioremap SKU-ROM LUT register for cpu %u\n", cpu);
	return -ENOMEM;
	}

	secondary_startup_phy = __pa_symbol(secondary_startup);
	BUG_ON(secondary_startup_phy > (phys_addr_t)U32_MAX);

	writel_relaxed(secondary_startup_phy, sku_rom_lut);

	/* Ensure the write is visible to the secondary core */
	smp_wmb();

	iounmap(sku_rom_lut);

	return 0;
	}

	static void __init bcm_smp_prepare_cpus(unsigned int max_cpus)
	{
	const cpumask_t only_cpu_0 = { CPU_BITS_CPU0 };

	/* Enable the SCU on Cortex A9 based SoCs */
	if (scu_a9_enable()) {
	/* Update the CPU present map to reflect uniprocessor mode */
	pr_warn("failed to enable A9 SCU - 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 kona_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;
	const u32 secondary_boot_addr = secondary_boot_addr_for(cpu);

	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_addr)
	return -EINVAL;

	boot_reg = ioremap_nocache((phys_addr_t)secondary_boot_addr,
	sizeof(phys_addr_t));
	if (!boot_reg) {
	pr_err("unable to map boot register for cpu %u\n", cpu_id);
	return -ENOMEM;
	}

	/*
	* Secondary cores will start in secondary_startup(),
	* defined in "arch/arm/kernel/head.S"
	*/
	boot_func = __pa_symbol(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 -ENXIO;
	}

	/* Cluster Dormant Control command to bring CPU into a running state */
	#define CDC_CMD 6
	#define CDC_CMD_OFFSET 0
	#define CDC_CMD_REG(cpu) (CDC_CMD_OFFSET + 4*(cpu))

	/*
	* BCM23550 has a Cluster Dormant Control block that keeps the core in
	* idle state. A command needs to be sent to the block to bring the CPU
	* into running state.
	*/
	static int bcm23550_boot_secondary(unsigned int cpu, struct task_struct *idle)
	{
	void __iomem *cdc_base;
	struct device_node *dn;
	char *name;
	int ret;

	/* Make sure a CDC node exists before booting the
	* secondary core.
	*/
	name = "brcm,bcm23550-cdc";
	dn = of_find_compatible_node(NULL, NULL, name);
	if (!dn) {
	pr_err("unable to find cdc node\n");
	return -ENODEV;
	}

	cdc_base = of_iomap(dn, 0);
	of_node_put(dn);

	if (!cdc_base) {
	pr_err("unable to remap cdc base register\n");
	return -ENOMEM;
	}

	/* Boot the secondary core */
	ret = kona_boot_secondary(cpu, idle);
	if (ret)
	goto out;

	/* Bring this CPU to RUN state so that nIRQ nFIQ
	* signals are unblocked.
	*/
	writel_relaxed(CDC_CMD, cdc_base + CDC_CMD_REG(cpu));

	out:
	iounmap(cdc_base);

	return ret;
	}

	static int nsp_boot_secondary(unsigned int cpu, struct task_struct *idle)
	{
	int ret;

	/*
	* After wake up, secondary core branches to the startup
	* address programmed at SKU ROM LUT location.
	*/
	ret = nsp_write_lut(cpu);
	if (ret) {
	pr_err("unable to write startup addr to SKU ROM LUT\n");
	goto out;
	}

	/* Send a CPU wakeup interrupt to the secondary core */
	arch_send_wakeup_ipi_mask(cpumask_of(cpu));

	out:
	return ret;
	}

	static int bcm2836_boot_secondary(unsigned int cpu, struct task_struct *idle)
	{
	void __iomem *intc_base;
	struct device_node *dn;
	char *name;

	name = "brcm,bcm2836-l1-intc";
	dn = of_find_compatible_node(NULL, NULL, name);
	if (!dn) {
	pr_err("unable to find intc node\n");
	return -ENODEV;
	}

	intc_base = of_iomap(dn, 0);
	of_node_put(dn);

	if (!intc_base) {
	pr_err("unable to remap intc base register\n");
	return -ENOMEM;
	}

	writel(virt_to_phys(secondary_startup),
	intc_base + LOCAL_MAILBOX3_SET0 + 16 * cpu);

	dsb(sy);
	sev();

	iounmap(intc_base);

	return 0;
	}

	static const struct smp_operations kona_smp_ops __initconst = {
	.smp_prepare_cpus = bcm_smp_prepare_cpus,
	.smp_boot_secondary = kona_boot_secondary,
	};
	CPU_METHOD_OF_DECLARE(bcm_smp_bcm281xx, "brcm,bcm11351-cpu-method",
	&kona_smp_ops);

	static const struct smp_operations bcm23550_smp_ops __initconst = {
	.smp_boot_secondary = bcm23550_boot_secondary,
	};
	CPU_METHOD_OF_DECLARE(bcm_smp_bcm23550, "brcm,bcm23550",
	&bcm23550_smp_ops);

	static const struct smp_operations nsp_smp_ops __initconst = {
	.smp_prepare_cpus = bcm_smp_prepare_cpus,
	.smp_boot_secondary = nsp_boot_secondary,
	};
	CPU_METHOD_OF_DECLARE(bcm_smp_nsp, "brcm,bcm-nsp-smp", &nsp_smp_ops);

	const struct smp_operations bcm2836_smp_ops __initconst = {
	.smp_boot_secondary = bcm2836_boot_secondary,
	};
	CPU_METHOD_OF_DECLARE(bcm_smp_bcm2836, "brcm,bcm2836-smp", &bcm2836_smp_ops);