From dca463daa0151c5bbbd8ec8fd42882a3966d3c44 Mon Sep 17 00:00:00 2001 From: Lorenzo Pieralisi Date: Thu, 15 Nov 2012 17:30:32 +0000 Subject: ARM: kernel: enhance MPIDR macro definitions Kernel subsystems other than the topology layer need the MPIDR mask definitions to access the MPIDR without relying on hardcoded masks. This patch moves the MPIDR register masks definition to a header file and defines a macro to simplify access to MPIDR bit fields representing affinity levels. Signed-off-by: Lorenzo Pieralisi Acked-by: Will Deacon Acked-by: Nicolas Pitre --- arch/arm/include/asm/cputype.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'arch/arm/include') diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h index cb47d28cbe1f..a59dcb5ab5fc 100644 --- a/arch/arm/include/asm/cputype.h +++ b/arch/arm/include/asm/cputype.h @@ -25,6 +25,19 @@ #define CPUID_EXT_ISAR4 "c2, 4" #define CPUID_EXT_ISAR5 "c2, 5" +#define MPIDR_SMP_BITMASK (0x3 << 30) +#define MPIDR_SMP_VALUE (0x2 << 30) + +#define MPIDR_MT_BITMASK (0x1 << 24) + +#define MPIDR_HWID_BITMASK 0xFFFFFF + +#define MPIDR_LEVEL_BITS 8 +#define MPIDR_LEVEL_MASK ((1 << MPIDR_LEVEL_BITS) - 1) + +#define MPIDR_AFFINITY_LEVEL(mpidr, level) \ + ((mpidr >> (MPIDR_LEVEL_BITS * level)) & MPIDR_LEVEL_MASK) + extern unsigned int processor_id; #ifdef CONFIG_CPU_CP15 -- cgit v1.2.3 From a0ae02405076ac32bd17ece976e914b5b6075bb0 Mon Sep 17 00:00:00 2001 From: Lorenzo Pieralisi Date: Thu, 17 Nov 2011 17:31:51 +0000 Subject: ARM: kernel: add device tree init map function When booting through a device tree, the kernel cpu logical id map can be initialized using device tree data passed by FW or through an embedded blob. This patch adds a function that parses device tree "cpu" nodes and retrieves the corresponding CPUs hardware identifiers (MPIDR). It sets the possible cpus and the cpu logical map values according to the number of CPUs defined in the device tree and respective properties. The device tree HW identifiers are considered valid if all CPU nodes contain a "reg" property, there are no duplicate "reg" entries and the DT defines a CPU node whose "reg" property matches the MPIDR[23:0] of the boot CPU. The primary CPU is assigned cpu logical number 0 to keep the current convention valid. Current bindings documentation is included in the patch: Documentation/devicetree/bindings/arm/cpus.txt Signed-off-by: Lorenzo Pieralisi Acked-by: Nicolas Pitre --- Documentation/devicetree/bindings/arm/cpus.txt | 77 +++++++++++++++++++ arch/arm/include/asm/prom.h | 2 + arch/arm/kernel/devtree.c | 100 +++++++++++++++++++++++++ 3 files changed, 179 insertions(+) create mode 100644 Documentation/devicetree/bindings/arm/cpus.txt (limited to 'arch/arm/include') diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt new file mode 100644 index 000000000000..f32494dbfe19 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/cpus.txt @@ -0,0 +1,77 @@ +* ARM CPUs binding description + +The device tree allows to describe the layout of CPUs in a system through +the "cpus" node, which in turn contains a number of subnodes (ie "cpu") +defining properties for every cpu. + +Bindings for CPU nodes follow the ePAPR standard, available from: + +http://devicetree.org + +For the ARM architecture every CPU node must contain the following properties: + +- device_type: must be "cpu" +- reg: property matching the CPU MPIDR[23:0] register bits + reg[31:24] bits must be set to 0 +- compatible: should be one of: + "arm,arm1020" + "arm,arm1020e" + "arm,arm1022" + "arm,arm1026" + "arm,arm720" + "arm,arm740" + "arm,arm7tdmi" + "arm,arm920" + "arm,arm922" + "arm,arm925" + "arm,arm926" + "arm,arm940" + "arm,arm946" + "arm,arm9tdmi" + "arm,cortex-a5" + "arm,cortex-a7" + "arm,cortex-a8" + "arm,cortex-a9" + "arm,cortex-a15" + "arm,arm1136" + "arm,arm1156" + "arm,arm1176" + "arm,arm11mpcore" + "faraday,fa526" + "intel,sa110" + "intel,sa1100" + "marvell,feroceon" + "marvell,mohawk" + "marvell,xsc3" + "marvell,xscale" + +Example: + + cpus { + #size-cells = <0>; + #address-cells = <1>; + + CPU0: cpu@0 { + device_type = "cpu"; + compatible = "arm,cortex-a15"; + reg = <0x0>; + }; + + CPU1: cpu@1 { + device_type = "cpu"; + compatible = "arm,cortex-a15"; + reg = <0x1>; + }; + + CPU2: cpu@100 { + device_type = "cpu"; + compatible = "arm,cortex-a7"; + reg = <0x100>; + }; + + CPU3: cpu@101 { + device_type = "cpu"; + compatible = "arm,cortex-a7"; + reg = <0x101>; + }; + }; diff --git a/arch/arm/include/asm/prom.h b/arch/arm/include/asm/prom.h index aeae9c609df4..8dd51dc1a367 100644 --- a/arch/arm/include/asm/prom.h +++ b/arch/arm/include/asm/prom.h @@ -15,6 +15,7 @@ extern struct machine_desc *setup_machine_fdt(unsigned int dt_phys); extern void arm_dt_memblock_reserve(void); +extern void __init arm_dt_init_cpu_maps(void); #else /* CONFIG_OF */ @@ -24,6 +25,7 @@ static inline struct machine_desc *setup_machine_fdt(unsigned int dt_phys) } static inline void arm_dt_memblock_reserve(void) { } +static inline void arm_dt_init_cpu_maps(void) { } #endif /* CONFIG_OF */ #endif /* ASMARM_PROM_H */ diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c index bee7f9d47f02..aaf9add497fe 100644 --- a/arch/arm/kernel/devtree.c +++ b/arch/arm/kernel/devtree.c @@ -19,8 +19,10 @@ #include #include +#include #include #include +#include #include #include @@ -61,6 +63,104 @@ void __init arm_dt_memblock_reserve(void) } } +/* + * 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; + 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] = UINT_MAX }; + bool bootcpu_valid = false; + cpus = of_find_node_by_path("/cpus"); + + if (!cpus) + return; + + for_each_child_of_node(cpus, cpu) { + u32 hwid; + + 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. + */ + if (of_property_read_u32(cpu, "reg", &hwid)) { + pr_debug(" * %s missing reg property\n", + cpu->full_name); + return; + } + + /* + * 8 MSBs must be set to 0 in the DT since the reg property + * defines the MPIDR[23:0]. + */ + if (hwid & ~MPIDR_HWID_BITMASK) + 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")) + 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++; + } + + tmp_map[i] = hwid; + + if (cpuidx > nr_cpu_ids) + break; + } + + if (WARN(!bootcpu_valid, "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)); + } +} + /** * setup_machine_fdt - Machine setup when an dtb was passed to the kernel * @dt_phys: physical address of dt blob -- cgit v1.2.3 From 7f124aaf01439d2fa54283f3c375ce3b9fc776d4 Mon Sep 17 00:00:00 2001 From: Lorenzo Pieralisi Date: Thu, 17 Nov 2011 17:36:24 +0000 Subject: ARM: kernel: add logical mappings look-up In ARM SMP systems the MPIDR register ([23:0] bits) is used to uniquely identify CPUs. In order to retrieve the logical CPU index corresponding to a given MPIDR value and guarantee a consistent translation throughout the kernel, this patch adds a look-up based on the MPIDR[23:0] so that kernel subsystems can use it whenever the logical cpu index corresponding to a given MPIDR value is needed. Signed-off-by: Lorenzo Pieralisi Acked-by: Will Deacon Acked-by: Nicolas Pitre --- arch/arm/include/asm/smp_plat.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'arch/arm/include') diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h index 558d6c80aca9..aaa61b6f50ff 100644 --- a/arch/arm/include/asm/smp_plat.h +++ b/arch/arm/include/asm/smp_plat.h @@ -5,6 +5,9 @@ #ifndef __ASMARM_SMP_PLAT_H #define __ASMARM_SMP_PLAT_H +#include +#include + #include /* @@ -48,5 +51,19 @@ static inline int cache_ops_need_broadcast(void) */ extern int __cpu_logical_map[]; #define cpu_logical_map(cpu) __cpu_logical_map[cpu] +/* + * Retrieve logical cpu index corresponding to a given MPIDR[23:0] + * - mpidr: MPIDR[23:0] to be used for the look-up + * + * Returns the cpu logical index or -EINVAL on look-up error + */ +static inline int get_logical_index(u32 mpidr) +{ + int cpu; + for (cpu = 0; cpu < nr_cpu_ids; cpu++) + if (cpu_logical_map(cpu) == mpidr) + return cpu; + return -EINVAL; +} #endif -- cgit v1.2.3