[mirror_ubuntu-artful-kernel.git] / arch / arm / mach-bcm / platsmp.c

/*
 * 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/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 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);
Commit	Line	Data
9a5a110e	1	/*
84320e1a	2	* Copyright (C) 2014-2015 Broadcom Corporation
9a5a110e AE	3	* Copyright 2014 Linaro Limited
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License as
	7	* published by the Free Software Foundation version 2.
	8	*
	9	* This program is distributed "as is" WITHOUT ANY WARRANTY of any
	10	* kind, whether express or implied; without even the implied warranty
	11	* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*/
	14
97890821 KH	15	#include <linux/cpumask.h>
97890821 KH	16	#include <linux/delay.h>
9a5a110e	17	#include <linux/errno.h>
97890821	18	#include <linux/init.h>
9a5a110e	19	#include <linux/io.h>
97890821	20	#include <linux/jiffies.h>
9a5a110e	21	#include <linux/of.h>
5fcf999a	22	#include <linux/of_address.h>
9a5a110e	23	#include <linux/sched.h>
e6017571	24	#include <linux/sched/clock.h>
97890821	25	#include <linux/smp.h>
9a5a110e	26
97890821	27	#include <asm/cacheflush.h>
9a5a110e AE	28	#include <asm/smp.h>
	29	#include <asm/smp_plat.h>
	30	#include <asm/smp_scu.h>
	31
	32	/* Size of mapped Cortex A9 SCU address space */
	33	#define CORTEX_A9_SCU_SIZE 0x58
	34
	35	#define SECONDARY_TIMEOUT_NS NSEC_PER_MSEC /* 1 msec (in nanoseconds) */
	36	#define BOOT_ADDR_CPUID_MASK 0x3
	37
	38	/* Name of device node property defining secondary boot register location */
	39	#define OF_SECONDARY_BOOT "secondary-boot-reg"
84320e1a	40	#define MPIDR_CPUID_BITMASK 0x3
9a5a110e	41
9a5a110e AE	42	/*
	43	* Enable the Cortex A9 Snoop Control Unit
	44	*
	45	* By the time this is called we already know there are multiple
	46	* cores present. We assume we're running on a Cortex A9 processor,
	47	* so any trouble getting the base address register or getting the
	48	* SCU base is a problem.
	49	*
	50	* Return 0 if successful or an error code otherwise.
	51	*/
	52	static int __init scu_a9_enable(void)
	53	{
	54	unsigned long config_base;
	55	void __iomem *scu_base;
	56
	57	if (!scu_a9_has_base()) {
	58	pr_err("no configuration base address register!\n");
	59	return -ENXIO;
	60	}
	61
	62	/* Config base address register value is zero for uniprocessor */
	63	config_base = scu_a9_get_base();
	64	if (!config_base) {
	65	pr_err("hardware reports only one core\n");
	66	return -ENOENT;
	67	}
	68
	69	scu_base = ioremap((phys_addr_t)config_base, CORTEX_A9_SCU_SIZE);
	70	if (!scu_base) {
	71	pr_err("failed to remap config base (%lu/%u) for SCU\n",
	72	config_base, CORTEX_A9_SCU_SIZE);
	73	return -ENOMEM;
	74	}
	75
	76	scu_enable(scu_base);
	77
	78	iounmap(scu_base); /* That's the last we'll need of this */
	79
	80	return 0;
	81	}
	82
6585cb5a CB	83	static u32 secondary_boot_addr_for(unsigned int cpu)
	84	{
	85	u32 secondary_boot_addr = 0;
	86	struct device_node *cpu_node = of_get_cpu_node(cpu, NULL);
	87
	88	if (!cpu_node) {
	89	pr_err("Failed to find device tree node for CPU%u\n", cpu);
	90	return 0;
	91	}
	92
	93	if (of_property_read_u32(cpu_node,
	94	OF_SECONDARY_BOOT,
	95	&secondary_boot_addr))
	96	pr_err("required secondary boot register not specified for CPU%u\n",
	97	cpu);
	98
	99	of_node_put(cpu_node);
	100
	101	return secondary_boot_addr;
	102	}
	103
	104	static int nsp_write_lut(unsigned int cpu)
97890821 KH	105	{
	106	void __iomem *sku_rom_lut;
	107	phys_addr_t secondary_startup_phy;
6585cb5a	108	const u32 secondary_boot_addr = secondary_boot_addr_for(cpu);
97890821	109
6585cb5a	110	if (!secondary_boot_addr)
97890821	111	return -EINVAL;
97890821 KH	112
97890821 KH	113	sku_rom_lut = ioremap_nocache((phys_addr_t)secondary_boot_addr,
6585cb5a	114	sizeof(phys_addr_t));
97890821	115	if (!sku_rom_lut) {
6585cb5a	116	pr_warn("unable to ioremap SKU-ROM LUT register for cpu %u\n", cpu);
97890821 KH	117	return -ENOMEM;
	118	}
	119
64fc2a94	120	secondary_startup_phy = __pa_symbol(secondary_startup);
97890821 KH	121	BUG_ON(secondary_startup_phy > (phys_addr_t)U32_MAX);
	122
	123	writel_relaxed(secondary_startup_phy, sku_rom_lut);
	124
	125	/* Ensure the write is visible to the secondary core */
	126	smp_wmb();
	127
	128	iounmap(sku_rom_lut);
	129
	130	return 0;
	131	}
	132
9a5a110e AE	133	static void __init bcm_smp_prepare_cpus(unsigned int max_cpus)
9a5a110e AE	134	{
6585cb5a	135	const cpumask_t only_cpu_0 = { CPU_BITS_CPU0 };
84320e1a	136
6585cb5a CB	137	/* Enable the SCU on Cortex A9 based SoCs */
6585cb5a CB	138	if (scu_a9_enable()) {
9a5a110e	139	/* Update the CPU present map to reflect uniprocessor mode */
6585cb5a	140	pr_warn("failed to enable A9 SCU - disabling SMP\n");
9a5a110e AE	141	init_cpu_present(&only_cpu_0);
	142	}
	143	}
	144
	145	/*
	146	* The ROM code has the secondary cores looping, waiting for an event.
	147	* When an event occurs each core examines the bottom two bits of the
	148	* secondary boot register. When a core finds those bits contain its
	149	* own core id, it performs initialization, including computing its boot
	150	* address by clearing the boot register value's bottom two bits. The
	151	* core signals that it is beginning its execution by writing its boot
	152	* address back to the secondary boot register, and finally jumps to
	153	* that address.
	154	*
	155	* So to start a core executing we need to:
	156	* - Encode the (hardware) CPU id with the bottom bits of the secondary
	157	* start address.
	158	* - Write that value into the secondary boot register.
	159	* - Generate an event to wake up the secondary CPU(s).
	160	* - Wait for the secondary boot register to be re-written, which
	161	* indicates the secondary core has started.
	162	*/
84320e1a	163	static int kona_boot_secondary(unsigned int cpu, struct task_struct *idle)
9a5a110e AE	164	{
	165	void __iomem *boot_reg;
	166	phys_addr_t boot_func;
	167	u64 start_clock;
	168	u32 cpu_id;
	169	u32 boot_val;
	170	bool timeout = false;
6585cb5a	171	const u32 secondary_boot_addr = secondary_boot_addr_for(cpu);
9a5a110e AE	172
	173	cpu_id = cpu_logical_map(cpu);
	174	if (cpu_id & ~BOOT_ADDR_CPUID_MASK) {
	175	pr_err("bad cpu id (%u > %u)\n", cpu_id, BOOT_ADDR_CPUID_MASK);
	176	return -EINVAL;
	177	}
	178
6585cb5a	179	if (!secondary_boot_addr)
9a5a110e	180	return -EINVAL;
9a5a110e	181
6585cb5a CB	182	boot_reg = ioremap_nocache((phys_addr_t)secondary_boot_addr,
6585cb5a CB	183	sizeof(phys_addr_t));
9a5a110e AE	184	if (!boot_reg) {
9a5a110e AE	185	pr_err("unable to map boot register for cpu %u\n", cpu_id);
84320e1a	186	return -ENOMEM;
9a5a110e AE	187	}
	188
	189	/*
	190	* Secondary cores will start in secondary_startup(),
	191	* defined in "arch/arm/kernel/head.S"
	192	*/
64fc2a94	193	boot_func = __pa_symbol(secondary_startup);
9a5a110e AE	194	BUG_ON(boot_func & BOOT_ADDR_CPUID_MASK);
	195	BUG_ON(boot_func > (phys_addr_t)U32_MAX);
	196
	197	/* The core to start is encoded in the low bits */
	198	boot_val = (u32)boot_func \| cpu_id;
	199	writel_relaxed(boot_val, boot_reg);
	200
	201	sev();
	202
	203	/* The low bits will be cleared once the core has started */
	204	start_clock = local_clock();
	205	while (!timeout && readl_relaxed(boot_reg) == boot_val)
	206	timeout = local_clock() - start_clock > SECONDARY_TIMEOUT_NS;
	207
	208	iounmap(boot_reg);
	209
	210	if (!timeout)
	211	return 0;
	212
	213	pr_err("timeout waiting for cpu %u to start\n", cpu_id);
	214
84320e1a	215	return -ENXIO;
9a5a110e AE	216	}
9a5a110e AE	217
5fcf999a CB	218	/* Cluster Dormant Control command to bring CPU into a running state */
	219	#define CDC_CMD 6
	220	#define CDC_CMD_OFFSET 0
	221	#define CDC_CMD_REG(cpu) (CDC_CMD_OFFSET + 4*(cpu))
	222
	223	/*
	224	* BCM23550 has a Cluster Dormant Control block that keeps the core in
	225	* idle state. A command needs to be sent to the block to bring the CPU
	226	* into running state.
	227	*/
	228	static int bcm23550_boot_secondary(unsigned int cpu, struct task_struct *idle)
	229	{
	230	void __iomem *cdc_base;
	231	struct device_node *dn;
	232	char *name;
	233	int ret;
	234
	235	/* Make sure a CDC node exists before booting the
	236	* secondary core.
	237	*/
	238	name = "brcm,bcm23550-cdc";
	239	dn = of_find_compatible_node(NULL, NULL, name);
	240	if (!dn) {
	241	pr_err("unable to find cdc node\n");
	242	return -ENODEV;
	243	}
	244
	245	cdc_base = of_iomap(dn, 0);
	246	of_node_put(dn);
	247
	248	if (!cdc_base) {
	249	pr_err("unable to remap cdc base register\n");
	250	return -ENOMEM;
	251	}
	252
	253	/* Boot the secondary core */
	254	ret = kona_boot_secondary(cpu, idle);
	255	if (ret)
	256	goto out;
	257
	258	/* Bring this CPU to RUN state so that nIRQ nFIQ
	259	* signals are unblocked.
	260	*/
	261	writel_relaxed(CDC_CMD, cdc_base + CDC_CMD_REG(cpu));
	262
	263	out:
	264	iounmap(cdc_base);
	265
	266	return ret;
	267	}
	268
97890821 KH	269	static int nsp_boot_secondary(unsigned int cpu, struct task_struct *idle)
	270	{
	271	int ret;
	272
	273	/*
	274	* After wake up, secondary core branches to the startup
	275	* address programmed at SKU ROM LUT location.
	276	*/
6585cb5a	277	ret = nsp_write_lut(cpu);
97890821 KH	278	if (ret) {
	279	pr_err("unable to write startup addr to SKU ROM LUT\n");
	280	goto out;
	281	}
	282
	283	/* Send a CPU wakeup interrupt to the secondary core */
	284	arch_send_wakeup_ipi_mask(cpumask_of(cpu));
	285
	286	out:
	287	return ret;
	288	}
	289
6585cb5a	290	static const struct smp_operations kona_smp_ops __initconst = {
9a5a110e	291	.smp_prepare_cpus = bcm_smp_prepare_cpus,
84320e1a	292	.smp_boot_secondary = kona_boot_secondary,
9a5a110e AE	293	};
9a5a110e AE	294	CPU_METHOD_OF_DECLARE(bcm_smp_bcm281xx, "brcm,bcm11351-cpu-method",
6585cb5a	295	&kona_smp_ops);
97890821	296
5fcf999a CB	297	static const struct smp_operations bcm23550_smp_ops __initconst = {
	298	.smp_boot_secondary = bcm23550_boot_secondary,
	299	};
	300	CPU_METHOD_OF_DECLARE(bcm_smp_bcm23550, "brcm,bcm23550",
	301	&bcm23550_smp_ops);
	302
9480e085	303	static const struct smp_operations nsp_smp_ops __initconst = {
97890821 KH	304	.smp_prepare_cpus = bcm_smp_prepare_cpus,
	305	.smp_boot_secondary = nsp_boot_secondary,
	306	};
	307	CPU_METHOD_OF_DECLARE(bcm_smp_nsp, "brcm,bcm-nsp-smp", &nsp_smp_ops);