arch/arm/mach-vexpress/dcscb.c - maze/linux - Git at Google

 /*
  * arch/arm/mach-vexpress/dcscb.c - Dual Cluster System Configuration Block
  *
  * Created by:	Nicolas Pitre, May 2012
  * Copyright:	(C) 2012-2013  Linaro 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 <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/io.h>
 #include <linux/spinlock.h>
 #include <linux/errno.h>
 #include <linux/of_address.h>
 #include <linux/vexpress.h>
 #include <linux/arm-cci.h>

 #include <asm/mcpm.h>
 #include <asm/proc-fns.h>
 #include <asm/cacheflush.h>
 #include <asm/cputype.h>
 #include <asm/cp15.h>


 #define RST_HOLD0	0x0
 #define RST_HOLD1	0x4
 #define SYS_SWRESET	0x8
 #define RST_STAT0	0xc
 #define RST_STAT1	0x10
 #define EAG_CFG_R	0x20
 #define EAG_CFG_W	0x24
 #define KFC_CFG_R	0x28
 #define KFC_CFG_W	0x2c
 #define DCS_CFG_R	0x30

 /*
  * We can't use regular spinlocks. In the switcher case, it is possible
  * for an outbound CPU to call power_down() while its inbound counterpart
  * is already live using the same logical CPU number which trips lockdep
  * debugging.
  */
 static arch_spinlock_t dcscb_lock = __ARCH_SPIN_LOCK_UNLOCKED;

 static void __iomem *dcscb_base;
 static int dcscb_use_count[4][2];
 static int dcscb_allcpus_mask[2];

 static int dcscb_power_up(unsigned int cpu, unsigned int cluster)
 {
 	unsigned int rst_hold, cpumask = (1 << cpu);
 	unsigned int all_mask = dcscb_allcpus_mask[cluster];

 	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
 	if (cpu >= 4 || cluster >= 2)
 		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(&dcscb_lock);

 	dcscb_use_count[cpu][cluster]++;
 	if (dcscb_use_count[cpu][cluster] == 1) {
 		rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
 		if (rst_hold & (1 << 8)) {
 			/* remove cluster reset and add individual CPU's reset */
 			rst_hold &= ~(1 << 8);
 			rst_hold |= all_mask;
 		}
 		rst_hold &= ~(cpumask | (cpumask << 4));
 		writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
 	} else if (dcscb_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(&dcscb_lock);
 	local_irq_enable();

 	return 0;
 }

 static void dcscb_power_down(void)
 {
 	unsigned int mpidr, cpu, cluster, rst_hold, cpumask, all_mask;
 	bool last_man = false, skip_wfi = false;

 	mpidr = read_cpuid_mpidr();
 	cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
 	cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
 	cpumask = (1 << cpu);
 	all_mask = dcscb_allcpus_mask[cluster];

 	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
 	BUG_ON(cpu >= 4 || cluster >= 2);

 	__mcpm_cpu_going_down(cpu, cluster);

 	arch_spin_lock(&dcscb_lock);
 	BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
 	dcscb_use_count[cpu][cluster]--;
 	if (dcscb_use_count[cpu][cluster] == 0) {
 		rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
 		rst_hold |= cpumask;
 		if (((rst_hold | (rst_hold >> 4)) & all_mask) == all_mask) {
 			rst_hold |= (1 << 8);
 			last_man = true;
 		}
 		writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
 	} else if (dcscb_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(&dcscb_lock);

 		/*
 		 * Flush all cache levels for this cluster.
 		 *
 		 * A15/A7 can hit in the cache with SCTLR.C=0, so we don't need
 		 * a preliminary flush here for those CPUs.  At least, that's
 		 * the theory -- without the extra flush, Linux explodes on
 		 * RTSM (to be investigated).
 		 */
 		flush_cache_all();
 		set_cr(get_cr() & ~CR_C);
 		flush_cache_all();

 		/*
 		 * This is a harmless no-op.  On platforms with a real
 		 * outer cache this might either be needed or not,
 		 * depending on where the outer cache sits.
 		 */
 		outer_flush_all();

 		/* Disable local coherency by clearing the ACTLR "SMP" bit: */
 		set_auxcr(get_auxcr() & ~(1 << 6));

 		/*
 		 * Disable cluster-level coherency by masking
 		 * incoming snoops and DVM messages:
 		 */
 		cci_disable_port_by_cpu(mpidr);

 		__mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN);
 	} else {
 		arch_spin_unlock(&dcscb_lock);

 		/*
 		 * Flush the local CPU cache.
 		 *
 		 * A15/A7 can hit in the cache with SCTLR.C=0, so we don't need
 		 * a preliminary flush here for those CPUs.  At least, that's
 		 * the theory -- without the extra flush, Linux explodes on
 		 * RTSM (to be investigated).
 		 */
 		flush_cache_louis();
 		set_cr(get_cr() & ~CR_C);
 		flush_cache_louis();

 		/* Disable local coherency by clearing the ACTLR "SMP" bit: */
 		set_auxcr(get_auxcr() & ~(1 << 6));
 	}

 	__mcpm_cpu_down(cpu, cluster);

 	/* Now we are prepared for power-down, do it: */
 	dsb();
 	if (!skip_wfi)
 		wfi();

 	/* Not dead at this point?  Let our caller cope. */
 }

 static const struct mcpm_platform_ops dcscb_power_ops = {
 	.power_up	= dcscb_power_up,
 	.power_down	= dcscb_power_down,
 };

 static void __init dcscb_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 >= 4 || cluster >= 2);
 	dcscb_use_count[cpu][cluster] = 1;
 }

 extern void dcscb_power_up_setup(unsigned int affinity_level);

 static int __init dcscb_init(void)
 {
 	struct device_node *node;
 	unsigned int cfg;
 	int ret;

 	if (!cci_probed())
 		return -ENODEV;

 	node = of_find_compatible_node(NULL, NULL, "arm,rtsm,dcscb");
 	if (!node)
 		return -ENODEV;
 	dcscb_base = of_iomap(node, 0);
 	if (!dcscb_base)
 		return -EADDRNOTAVAIL;
 	cfg = readl_relaxed(dcscb_base + DCS_CFG_R);
 	dcscb_allcpus_mask[0] = (1 << (((cfg >> 16) >> (0 << 2)) & 0xf)) - 1;
 	dcscb_allcpus_mask[1] = (1 << (((cfg >> 16) >> (1 << 2)) & 0xf)) - 1;
 	dcscb_usage_count_init();

 	ret = mcpm_platform_register(&dcscb_power_ops);
 	if (!ret)
 		ret = mcpm_sync_init(dcscb_power_up_setup);
 	if (ret) {
 		iounmap(dcscb_base);
 		return ret;
 	}

 	pr_info("VExpress DCSCB support installed\n");

 	/*
 	 * Future entries into the kernel can now go
 	 * through the cluster entry vectors.
 	 */
 	vexpress_flags_set(virt_to_phys(mcpm_entry_point));

 	return 0;
 }

 early_initcall(dcscb_init);
	/*
	* arch/arm/mach-vexpress/dcscb.c - Dual Cluster System Configuration Block
	*
	* Created by: Nicolas Pitre, May 2012
	* Copyright: (C) 2012-2013 Linaro 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 <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/io.h>
	#include <linux/spinlock.h>
	#include <linux/errno.h>
	#include <linux/of_address.h>
	#include <linux/vexpress.h>
	#include <linux/arm-cci.h>

	#include <asm/mcpm.h>
	#include <asm/proc-fns.h>
	#include <asm/cacheflush.h>
	#include <asm/cputype.h>
	#include <asm/cp15.h>


	#define RST_HOLD0 0x0
	#define RST_HOLD1 0x4
	#define SYS_SWRESET 0x8
	#define RST_STAT0 0xc
	#define RST_STAT1 0x10
	#define EAG_CFG_R 0x20
	#define EAG_CFG_W 0x24
	#define KFC_CFG_R 0x28
	#define KFC_CFG_W 0x2c
	#define DCS_CFG_R 0x30

	/*
	* We can't use regular spinlocks. In the switcher case, it is possible
	* for an outbound CPU to call power_down() while its inbound counterpart
	* is already live using the same logical CPU number which trips lockdep
	* debugging.
	*/
	static arch_spinlock_t dcscb_lock = __ARCH_SPIN_LOCK_UNLOCKED;

	static void __iomem *dcscb_base;
	static int dcscb_use_count[4][2];
	static int dcscb_allcpus_mask[2];

	static int dcscb_power_up(unsigned int cpu, unsigned int cluster)
	{
	unsigned int rst_hold, cpumask = (1 << cpu);
	unsigned int all_mask = dcscb_allcpus_mask[cluster];

	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
	if (cpu >= 4 \|\| cluster >= 2)
	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(&dcscb_lock);

	dcscb_use_count[cpu][cluster]++;
	if (dcscb_use_count[cpu][cluster] == 1) {
	rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
	if (rst_hold & (1 << 8)) {
	/* remove cluster reset and add individual CPU's reset */
	rst_hold &= ~(1 << 8);
	rst_hold \|= all_mask;
	}
	rst_hold &= ~(cpumask \| (cpumask << 4));
	writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
	} else if (dcscb_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(&dcscb_lock);
	local_irq_enable();

	return 0;
	}

	static void dcscb_power_down(void)
	{
	unsigned int mpidr, cpu, cluster, rst_hold, cpumask, all_mask;
	bool last_man = false, skip_wfi = false;

	mpidr = read_cpuid_mpidr();
	cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
	cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
	cpumask = (1 << cpu);
	all_mask = dcscb_allcpus_mask[cluster];

	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
	BUG_ON(cpu >= 4 \|\| cluster >= 2);

	__mcpm_cpu_going_down(cpu, cluster);

	arch_spin_lock(&dcscb_lock);
	BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
	dcscb_use_count[cpu][cluster]--;
	if (dcscb_use_count[cpu][cluster] == 0) {
	rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
	rst_hold \|= cpumask;
	if (((rst_hold \| (rst_hold >> 4)) & all_mask) == all_mask) {
	rst_hold \|= (1 << 8);
	last_man = true;
	}
	writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
	} else if (dcscb_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(&dcscb_lock);

	/*
	* Flush all cache levels for this cluster.
	*
	* A15/A7 can hit in the cache with SCTLR.C=0, so we don't need
	* a preliminary flush here for those CPUs. At least, that's
	* the theory -- without the extra flush, Linux explodes on
	* RTSM (to be investigated).
	*/
	flush_cache_all();
	set_cr(get_cr() & ~CR_C);
	flush_cache_all();

	/*
	* This is a harmless no-op. On platforms with a real
	* outer cache this might either be needed or not,
	* depending on where the outer cache sits.
	*/
	outer_flush_all();

	/* Disable local coherency by clearing the ACTLR "SMP" bit: */
	set_auxcr(get_auxcr() & ~(1 << 6));

	/*
	* Disable cluster-level coherency by masking
	* incoming snoops and DVM messages:
	*/
	cci_disable_port_by_cpu(mpidr);

	__mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN);
	} else {
	arch_spin_unlock(&dcscb_lock);

	/*
	* Flush the local CPU cache.
	*
	* A15/A7 can hit in the cache with SCTLR.C=0, so we don't need
	* a preliminary flush here for those CPUs. At least, that's
	* the theory -- without the extra flush, Linux explodes on
	* RTSM (to be investigated).
	*/
	flush_cache_louis();
	set_cr(get_cr() & ~CR_C);
	flush_cache_louis();

	/* Disable local coherency by clearing the ACTLR "SMP" bit: */
	set_auxcr(get_auxcr() & ~(1 << 6));
	}

	__mcpm_cpu_down(cpu, cluster);

	/* Now we are prepared for power-down, do it: */
	dsb();
	if (!skip_wfi)
	wfi();

	/* Not dead at this point? Let our caller cope. */
	}

	static const struct mcpm_platform_ops dcscb_power_ops = {
	.power_up = dcscb_power_up,
	.power_down = dcscb_power_down,
	};

	static void __init dcscb_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 >= 4 \|\| cluster >= 2);
	dcscb_use_count[cpu][cluster] = 1;
	}

	extern void dcscb_power_up_setup(unsigned int affinity_level);

	static int __init dcscb_init(void)
	{
	struct device_node *node;
	unsigned int cfg;
	int ret;

	if (!cci_probed())
	return -ENODEV;

	node = of_find_compatible_node(NULL, NULL, "arm,rtsm,dcscb");
	if (!node)
	return -ENODEV;
	dcscb_base = of_iomap(node, 0);
	if (!dcscb_base)
	return -EADDRNOTAVAIL;
	cfg = readl_relaxed(dcscb_base + DCS_CFG_R);
	dcscb_allcpus_mask[0] = (1 << (((cfg >> 16) >> (0 << 2)) & 0xf)) - 1;
	dcscb_allcpus_mask[1] = (1 << (((cfg >> 16) >> (1 << 2)) & 0xf)) - 1;
	dcscb_usage_count_init();

	ret = mcpm_platform_register(&dcscb_power_ops);
	if (!ret)
	ret = mcpm_sync_init(dcscb_power_up_setup);
	if (ret) {
	iounmap(dcscb_base);
	return ret;
	}

	pr_info("VExpress DCSCB support installed\n");

	/*
	* Future entries into the kernel can now go
	* through the cluster entry vectors.
	*/
	vexpress_flags_set(virt_to_phys(mcpm_entry_point));

	return 0;
	}

	early_initcall(dcscb_init);