arch/arm/kernel/devtree.c - third_party/linux - Git at Google

 /*
  *  linux/arch/arm/kernel/devtree.c
  *
  *  Copyright (C) 2009 Canonical Ltd. <jeremy.kerr@canonical.com>
  *
  * 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/export.h>
 #include <linux/errno.h>
 #include <linux/types.h>
 #include <linux/bootmem.h>
 #include <linux/memblock.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/smp.h>

 #include <asm/cputype.h>
 #include <asm/setup.h>
 #include <asm/page.h>
 #include <asm/smp_plat.h>
 #include <asm/mach/arch.h>
 #include <asm/mach-types.h>


 #ifdef CONFIG_SMP
 extern struct of_cpu_method __cpu_method_of_table[];

 static const struct of_cpu_method __cpu_method_of_table_sentinel
 	__used __section(__cpu_method_of_table_end);


 static int __init set_smp_ops_by_method(struct device_node *node)
 {
 	const char *method;
 	struct of_cpu_method *m = __cpu_method_of_table;

 	if (of_property_read_string(node, "enable-method", &method))
 		return 0;

 	for (; m->method; m++)
 		if (!strcmp(m->method, method)) {
 			smp_set_ops(m->ops);
 			return 1;
 		}

 	return 0;
 }
 #else
 static inline int set_smp_ops_by_method(struct device_node *node)
 {
 	return 1;
 }
 #endif


 /*
  * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
  * and builds the cpu logical map array containing MPIDR values related to
  * logical cpus
  *
  * Updates the cpu possible mask with the number of parsed cpu nodes
  */
 void __init arm_dt_init_cpu_maps(void)
 {
 	/*
 	 * Temp logical map is initialized with UINT_MAX values that are
 	 * considered invalid logical map entries since the logical map must
 	 * contain a list of MPIDR[23:0] values where MPIDR[31:24] must
 	 * read as 0.
 	 */
 	struct device_node *cpu, *cpus;
 	int found_method = 0;
 	u32 i, j, cpuidx = 1;
 	u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;

 	u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
 	bool bootcpu_valid = false;
 	cpus = of_find_node_by_path("/cpus");

 	if (!cpus)
 		return;

 	for_each_child_of_node(cpus, cpu) {
 		const __be32 *cell;
 		int prop_bytes;
 		u32 hwid;

 		if (of_node_cmp(cpu->type, "cpu"))
 			continue;

 		pr_debug(" * %s...\n", cpu->full_name);
 		/*
 		 * A device tree containing CPU nodes with missing "reg"
 		 * properties is considered invalid to build the
 		 * cpu_logical_map.
 		 */
 		cell = of_get_property(cpu, "reg", &prop_bytes);
 		if (!cell || prop_bytes < sizeof(*cell)) {
 			pr_debug(" * %s missing reg property\n",
 				     cpu->full_name);
 			of_node_put(cpu);
 			return;
 		}

 		/*
 		 * Bits n:24 must be set to 0 in the DT since the reg property
 		 * defines the MPIDR[23:0].
 		 */
 		do {
 			hwid = be32_to_cpu(*cell++);
 			prop_bytes -= sizeof(*cell);
 		} while (!hwid && prop_bytes > 0);

 		if (prop_bytes || (hwid & ~MPIDR_HWID_BITMASK)) {
 			of_node_put(cpu);
 			return;
 		}

 		/*
 		 * Duplicate MPIDRs are a recipe for disaster.
 		 * Scan all initialized entries and check for
 		 * duplicates. If any is found just bail out.
 		 * temp values were initialized to UINT_MAX
 		 * to avoid matching valid MPIDR[23:0] values.
 		 */
 		for (j = 0; j < cpuidx; j++)
 			if (WARN(tmp_map[j] == hwid,
 				 "Duplicate /cpu reg properties in the DT\n")) {
 				of_node_put(cpu);
 				return;
 			}

 		/*
 		 * Build a stashed array of MPIDR values. Numbering scheme
 		 * requires that if detected the boot CPU must be assigned
 		 * logical id 0. Other CPUs get sequential indexes starting
 		 * from 1. If a CPU node with a reg property matching the
 		 * boot CPU MPIDR is detected, this is recorded so that the
 		 * logical map built from DT is validated and can be used
 		 * to override the map created in smp_setup_processor_id().
 		 */
 		if (hwid == mpidr) {
 			i = 0;
 			bootcpu_valid = true;
 		} else {
 			i = cpuidx++;
 		}

 		if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
 					       "max cores %u, capping them\n",
 					       cpuidx, nr_cpu_ids)) {
 			cpuidx = nr_cpu_ids;
 			of_node_put(cpu);
 			break;
 		}

 		tmp_map[i] = hwid;

 		if (!found_method)
 			found_method = set_smp_ops_by_method(cpu);
 	}

 	/*
 	 * Fallback to an enable-method in the cpus node if nothing found in
 	 * a cpu node.
 	 */
 	if (!found_method)
 		set_smp_ops_by_method(cpus);

 	if (!bootcpu_valid) {
 		pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
 		return;
 	}

 	/*
 	 * Since the boot CPU node contains proper data, and all nodes have
 	 * a reg property, the DT CPU list can be considered valid and the
 	 * logical map created in smp_setup_processor_id() can be overridden
 	 */
 	for (i = 0; i < cpuidx; i++) {
 		set_cpu_possible(i, true);
 		cpu_logical_map(i) = tmp_map[i];
 		pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i));
 	}
 }

 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
 {
 	return phys_id == cpu_logical_map(cpu);
 }

 static const void * __init arch_get_next_mach(const char *const **match)
 {
 	static const struct machine_desc *mdesc = __arch_info_begin;
 	const struct machine_desc *m = mdesc;

 	if (m >= __arch_info_end)
 		return NULL;

 	mdesc++;
 	*match = m->dt_compat;
 	return m;
 }

 /**
  * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
  * @dt_phys: physical address of dt blob
  *
  * If a dtb was passed to the kernel in r2, then use it to choose the
  * correct machine_desc and to setup the system.
  */
 const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
 {
 	const struct machine_desc *mdesc, *mdesc_best = NULL;

 #ifdef CONFIG_ARCH_MULTIPLATFORM
 	DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
 	MACHINE_END

 	mdesc_best = &__mach_desc_GENERIC_DT;
 #endif

 	if (!dt_phys || !early_init_dt_verify(phys_to_virt(dt_phys)))
 		return NULL;

 	mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);

 	if (!mdesc) {
 		const char *prop;
 		int size;
 		unsigned long dt_root;

 		early_print("\nError: unrecognized/unsupported "
 			    "device tree compatible list:\n[ ");

 		dt_root = of_get_flat_dt_root();
 		prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
 		while (size > 0) {
 			early_print("'%s' ", prop);
 			size -= strlen(prop) + 1;
 			prop += strlen(prop) + 1;
 		}
 		early_print("]\n\n");

 		dump_machine_table(); /* does not return */
 	}

 	/* We really don't want to do this, but sometimes firmware provides buggy data */
 	if (mdesc->dt_fixup)
 		mdesc->dt_fixup();

 	early_init_dt_scan_nodes();

 	/* Change machine number to match the mdesc we're using */
 	__machine_arch_type = mdesc->nr;

 	return mdesc;
 }
	/*
	* linux/arch/arm/kernel/devtree.c
	*
	* Copyright (C) 2009 Canonical Ltd. <jeremy.kerr@canonical.com>
	*
	* 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/export.h>
	#include <linux/errno.h>
	#include <linux/types.h>
	#include <linux/bootmem.h>
	#include <linux/memblock.h>
	#include <linux/of.h>
	#include <linux/of_fdt.h>
	#include <linux/of_irq.h>
	#include <linux/of_platform.h>
	#include <linux/smp.h>

	#include <asm/cputype.h>
	#include <asm/setup.h>
	#include <asm/page.h>
	#include <asm/smp_plat.h>
	#include <asm/mach/arch.h>
	#include <asm/mach-types.h>


	#ifdef CONFIG_SMP
	extern struct of_cpu_method __cpu_method_of_table[];

	static const struct of_cpu_method __cpu_method_of_table_sentinel
	__used __section(__cpu_method_of_table_end);


	static int __init set_smp_ops_by_method(struct device_node *node)
	{
	const char *method;
	struct of_cpu_method *m = __cpu_method_of_table;

	if (of_property_read_string(node, "enable-method", &method))
	return 0;

	for (; m->method; m++)
	if (!strcmp(m->method, method)) {
	smp_set_ops(m->ops);
	return 1;
	}

	return 0;
	}
	#else
	static inline int set_smp_ops_by_method(struct device_node *node)
	{
	return 1;
	}
	#endif


	/*
	* arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
	* and builds the cpu logical map array containing MPIDR values related to
	* logical cpus
	*
	* Updates the cpu possible mask with the number of parsed cpu nodes
	*/
	void __init arm_dt_init_cpu_maps(void)
	{
	/*
	* Temp logical map is initialized with UINT_MAX values that are
	* considered invalid logical map entries since the logical map must
	* contain a list of MPIDR[23:0] values where MPIDR[31:24] must
	* read as 0.
	*/
	struct device_node cpu, cpus;
	int found_method = 0;
	u32 i, j, cpuidx = 1;
	u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;

	u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
	bool bootcpu_valid = false;
	cpus = of_find_node_by_path("/cpus");

	if (!cpus)
	return;

	for_each_child_of_node(cpus, cpu) {
	const __be32 *cell;
	int prop_bytes;
	u32 hwid;

	if (of_node_cmp(cpu->type, "cpu"))
	continue;

	pr_debug(" * %s...\n", cpu->full_name);
	/*
	* A device tree containing CPU nodes with missing "reg"
	* properties is considered invalid to build the
	* cpu_logical_map.
	*/
	cell = of_get_property(cpu, "reg", &prop_bytes);
	if (!cell \|\| prop_bytes < sizeof(*cell)) {
	pr_debug(" * %s missing reg property\n",
	cpu->full_name);
	of_node_put(cpu);
	return;
	}

	/*
	* Bits n:24 must be set to 0 in the DT since the reg property
	* defines the MPIDR[23:0].
	*/
	do {
	hwid = be32_to_cpu(*cell++);
	prop_bytes -= sizeof(*cell);
	} while (!hwid && prop_bytes > 0);

	if (prop_bytes \|\| (hwid & ~MPIDR_HWID_BITMASK)) {
	of_node_put(cpu);
	return;
	}

	/*
	* Duplicate MPIDRs are a recipe for disaster.
	* Scan all initialized entries and check for
	* duplicates. If any is found just bail out.
	* temp values were initialized to UINT_MAX
	* to avoid matching valid MPIDR[23:0] values.
	*/
	for (j = 0; j < cpuidx; j++)
	if (WARN(tmp_map[j] == hwid,
	"Duplicate /cpu reg properties in the DT\n")) {
	of_node_put(cpu);
	return;
	}

	/*
	* Build a stashed array of MPIDR values. Numbering scheme
	* requires that if detected the boot CPU must be assigned
	* logical id 0. Other CPUs get sequential indexes starting
	* from 1. If a CPU node with a reg property matching the
	* boot CPU MPIDR is detected, this is recorded so that the
	* logical map built from DT is validated and can be used
	* to override the map created in smp_setup_processor_id().
	*/
	if (hwid == mpidr) {
	i = 0;
	bootcpu_valid = true;
	} else {
	i = cpuidx++;
	}

	if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than "
	"max cores %u, capping them\n",
	cpuidx, nr_cpu_ids)) {
	cpuidx = nr_cpu_ids;
	of_node_put(cpu);
	break;
	}

	tmp_map[i] = hwid;

	if (!found_method)
	found_method = set_smp_ops_by_method(cpu);
	}

	/*
	* Fallback to an enable-method in the cpus node if nothing found in
	* a cpu node.
	*/
	if (!found_method)
	set_smp_ops_by_method(cpus);

	if (!bootcpu_valid) {
	pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
	return;
	}

	/*
	* Since the boot CPU node contains proper data, and all nodes have
	* a reg property, the DT CPU list can be considered valid and the
	* logical map created in smp_setup_processor_id() can be overridden
	*/
	for (i = 0; i < cpuidx; i++) {
	set_cpu_possible(i, true);
	cpu_logical_map(i) = tmp_map[i];
	pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i));
	}
	}

	bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
	{
	return phys_id == cpu_logical_map(cpu);
	}

	static const void * __init arch_get_next_mach(const char const *match)
	{
	static const struct machine_desc *mdesc = __arch_info_begin;
	const struct machine_desc *m = mdesc;

	if (m >= __arch_info_end)
	return NULL;

	mdesc++;
	*match = m->dt_compat;
	return m;
	}

	/**
	* setup_machine_fdt - Machine setup when an dtb was passed to the kernel
	* @dt_phys: physical address of dt blob
	*
	* If a dtb was passed to the kernel in r2, then use it to choose the
	* correct machine_desc and to setup the system.
	*/
	const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
	{
	const struct machine_desc mdesc, mdesc_best = NULL;

	#ifdef CONFIG_ARCH_MULTIPLATFORM
	DT_MACHINE_START(GENERIC_DT, "Generic DT based system")
	MACHINE_END

	mdesc_best = &__mach_desc_GENERIC_DT;
	#endif

	if (!dt_phys \|\| !early_init_dt_verify(phys_to_virt(dt_phys)))
	return NULL;

	mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);

	if (!mdesc) {
	const char *prop;
	int size;
	unsigned long dt_root;

	early_print("\nError: unrecognized/unsupported "
	"device tree compatible list:\n[ ");

	dt_root = of_get_flat_dt_root();
	prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
	while (size > 0) {
	early_print("'%s' ", prop);
	size -= strlen(prop) + 1;
	prop += strlen(prop) + 1;
	}
	early_print("]\n\n");

	dump_machine_table(); /* does not return */
	}

	/* We really don't want to do this, but sometimes firmware provides buggy data */
	if (mdesc->dt_fixup)
	mdesc->dt_fixup();

	early_init_dt_scan_nodes();

	/* Change machine number to match the mdesc we're using */
	__machine_arch_type = mdesc->nr;

	return mdesc;
	}