cpufreq: ARM big LITTLE: Add generic cpufreq driver and its DT glue
big LITTLE is ARM's new Architecture focussing power/performance needs of modern world. More information about big LITTLE can be found here: http://www.arm.com/products/processors/technologies/biglittleprocessing.php http://lwn.net/Articles/481055/ In order to keep cpufreq support for all big LITTLE platforms simple/generic, this patch tries to add a generic cpufreq driver layer for all big LITTLE platforms. The driver is divided into two parts: - Core driver: Generic and shared across all big LITTLE SoC's - Glue drivers: Per platform drivers providing ops to the core driver This patch adds in a generic glue driver which would extract information from Device Tree. Future SoC's can either reuse the DT glue or write their own depending on the need. Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Viresh Kumar
Rafael J. Wysocki
parent
eb2f50ff93
commit
8a67f0ef2b
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@ -0,0 +1,65 @@
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Generic ARM big LITTLE cpufreq driver's DT glue
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-----------------------------------------------
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This is DT specific glue layer for generic cpufreq driver for big LITTLE
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systems.
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Both required and optional properties listed below must be defined
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under node /cpus/cpu@x. Where x is the first cpu inside a cluster.
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FIXME: Cpus should boot in the order specified in DT and all cpus for a cluster
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must be present contiguously. Generic DT driver will check only node 'x' for
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cpu:x.
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Required properties:
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- operating-points: Refer to Documentation/devicetree/bindings/power/opp.txt
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for details
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Optional properties:
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- clock-latency: Specify the possible maximum transition latency for clock,
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in unit of nanoseconds.
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Examples:
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cpus {
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#address-cells = <1>;
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#size-cells = <0>;
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cpu@0 {
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compatible = "arm,cortex-a15";
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reg = <0>;
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next-level-cache = <&L2>;
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operating-points = <
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/* kHz uV */
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792000 1100000
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396000 950000
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198000 850000
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>;
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clock-latency = <61036>; /* two CLK32 periods */
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};
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cpu@1 {
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compatible = "arm,cortex-a15";
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reg = <1>;
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next-level-cache = <&L2>;
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};
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cpu@100 {
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compatible = "arm,cortex-a7";
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reg = <100>;
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next-level-cache = <&L2>;
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operating-points = <
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/* kHz uV */
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792000 950000
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396000 750000
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198000 450000
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>;
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clock-latency = <61036>; /* two CLK32 periods */
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};
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cpu@101 {
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compatible = "arm,cortex-a7";
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reg = <101>;
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next-level-cache = <&L2>;
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};
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};
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11
MAINTAINERS
11
MAINTAINERS
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@ -2206,6 +2206,17 @@ S: Maintained
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F: drivers/cpufreq/
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F: drivers/cpufreq/
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F: include/linux/cpufreq.h
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F: include/linux/cpufreq.h
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CPU FREQUENCY DRIVERS - ARM BIG LITTLE
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M: Viresh Kumar <viresh.kumar@linaro.org>
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M: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
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L: cpufreq@vger.kernel.org
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L: linux-pm@vger.kernel.org
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W: http://www.arm.com/products/processors/technologies/biglittleprocessing.php
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S: Maintained
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F: drivers/cpufreq/arm_big_little.h
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F: drivers/cpufreq/arm_big_little.c
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F: drivers/cpufreq/arm_big_little_dt.c
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CPUID/MSR DRIVER
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CPUID/MSR DRIVER
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M: "H. Peter Anvin" <hpa@zytor.com>
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M: "H. Peter Anvin" <hpa@zytor.com>
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S: Maintained
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S: Maintained
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@ -2,6 +2,18 @@
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# ARM CPU Frequency scaling drivers
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# ARM CPU Frequency scaling drivers
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#
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#
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config ARM_BIG_LITTLE_CPUFREQ
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tristate
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depends on ARM_CPU_TOPOLOGY
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config ARM_DT_BL_CPUFREQ
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tristate "Generic ARM big LITTLE CPUfreq driver probed via DT"
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select ARM_BIG_LITTLE_CPUFREQ
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depends on OF && HAVE_CLK
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help
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This enables the Generic CPUfreq driver for ARM big.LITTLE platform.
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This gets frequency tables from DT.
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config ARM_OMAP2PLUS_CPUFREQ
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config ARM_OMAP2PLUS_CPUFREQ
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bool "TI OMAP2+"
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bool "TI OMAP2+"
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depends on ARCH_OMAP2PLUS
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depends on ARCH_OMAP2PLUS
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@ -44,6 +44,11 @@ obj-$(CONFIG_X86_INTEL_PSTATE) += intel_pstate.o
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##################################################################################
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##################################################################################
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# ARM SoC drivers
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# ARM SoC drivers
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obj-$(CONFIG_ARM_BIG_LITTLE_CPUFREQ) += arm_big_little.o
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# big LITTLE per platform glues. Keep DT_BL_CPUFREQ as the last entry in all big
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# LITTLE drivers, so that it is probed last.
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obj-$(CONFIG_ARM_DT_BL_CPUFREQ) += arm_big_little_dt.o
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obj-$(CONFIG_UX500_SOC_DB8500) += dbx500-cpufreq.o
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obj-$(CONFIG_UX500_SOC_DB8500) += dbx500-cpufreq.o
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obj-$(CONFIG_ARM_S3C2416_CPUFREQ) += s3c2416-cpufreq.o
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obj-$(CONFIG_ARM_S3C2416_CPUFREQ) += s3c2416-cpufreq.o
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obj-$(CONFIG_ARM_S3C64XX_CPUFREQ) += s3c64xx-cpufreq.o
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obj-$(CONFIG_ARM_S3C64XX_CPUFREQ) += s3c64xx-cpufreq.o
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@ -0,0 +1,282 @@
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/*
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* ARM big.LITTLE Platforms CPUFreq support
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*
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* Copyright (C) 2013 ARM Ltd.
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* Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
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*
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* Copyright (C) 2013 Linaro.
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* Viresh Kumar <viresh.kumar@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether express or implied; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/clk.h>
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#include <linux/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/cpumask.h>
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#include <linux/export.h>
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#include <linux/of_platform.h>
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#include <linux/opp.h>
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#include <linux/slab.h>
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#include <linux/topology.h>
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#include <linux/types.h>
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#include "arm_big_little.h"
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/* Currently we support only two clusters */
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#define MAX_CLUSTERS 2
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static struct cpufreq_arm_bL_ops *arm_bL_ops;
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static struct clk *clk[MAX_CLUSTERS];
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static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS];
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static atomic_t cluster_usage[MAX_CLUSTERS] = {ATOMIC_INIT(0), ATOMIC_INIT(0)};
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static int cpu_to_cluster(int cpu)
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{
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return topology_physical_package_id(cpu);
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}
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static unsigned int bL_cpufreq_get(unsigned int cpu)
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{
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u32 cur_cluster = cpu_to_cluster(cpu);
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return clk_get_rate(clk[cur_cluster]) / 1000;
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}
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/* Validate policy frequency range */
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static int bL_cpufreq_verify_policy(struct cpufreq_policy *policy)
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{
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u32 cur_cluster = cpu_to_cluster(policy->cpu);
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return cpufreq_frequency_table_verify(policy, freq_table[cur_cluster]);
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}
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/* Set clock frequency */
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static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
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unsigned int target_freq, unsigned int relation)
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{
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struct cpufreq_freqs freqs;
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u32 cpu = policy->cpu, freq_tab_idx, cur_cluster;
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int ret = 0;
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cur_cluster = cpu_to_cluster(policy->cpu);
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freqs.old = bL_cpufreq_get(policy->cpu);
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/* Determine valid target frequency using freq_table */
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cpufreq_frequency_table_target(policy, freq_table[cur_cluster],
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target_freq, relation, &freq_tab_idx);
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freqs.new = freq_table[cur_cluster][freq_tab_idx].frequency;
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freqs.cpu = policy->cpu;
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pr_debug("%s: cpu: %d, cluster: %d, oldfreq: %d, target freq: %d, new freq: %d\n",
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__func__, cpu, cur_cluster, freqs.old, target_freq,
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freqs.new);
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if (freqs.old == freqs.new)
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return 0;
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for_each_cpu(freqs.cpu, policy->cpus)
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cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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ret = clk_set_rate(clk[cur_cluster], freqs.new * 1000);
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if (ret) {
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pr_err("clk_set_rate failed: %d\n", ret);
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return ret;
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}
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policy->cur = freqs.new;
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for_each_cpu(freqs.cpu, policy->cpus)
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cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
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return ret;
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}
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static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
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{
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u32 cluster = cpu_to_cluster(cpu_dev->id);
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if (!atomic_dec_return(&cluster_usage[cluster])) {
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clk_put(clk[cluster]);
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opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
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dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
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}
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}
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static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
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{
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u32 cluster = cpu_to_cluster(cpu_dev->id);
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char name[14] = "cpu-cluster.";
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int ret;
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if (atomic_inc_return(&cluster_usage[cluster]) != 1)
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return 0;
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ret = arm_bL_ops->init_opp_table(cpu_dev);
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if (ret) {
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dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
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__func__, cpu_dev->id, ret);
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goto atomic_dec;
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}
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ret = opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
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if (ret) {
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dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
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__func__, cpu_dev->id, ret);
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goto atomic_dec;
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}
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name[12] = cluster + '0';
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clk[cluster] = clk_get_sys(name, NULL);
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if (!IS_ERR(clk[cluster])) {
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dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
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__func__, clk[cluster], freq_table[cluster],
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cluster);
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return 0;
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}
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dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
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__func__, cpu_dev->id, cluster);
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ret = PTR_ERR(clk[cluster]);
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opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
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atomic_dec:
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atomic_dec(&cluster_usage[cluster]);
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dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
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cluster);
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return ret;
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}
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/* Per-CPU initialization */
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static int bL_cpufreq_init(struct cpufreq_policy *policy)
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{
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u32 cur_cluster = cpu_to_cluster(policy->cpu);
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struct device *cpu_dev;
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int ret;
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cpu_dev = get_cpu_device(policy->cpu);
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if (!cpu_dev) {
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pr_err("%s: failed to get cpu%d device\n", __func__,
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policy->cpu);
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return -ENODEV;
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}
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ret = get_cluster_clk_and_freq_table(cpu_dev);
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if (ret)
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return ret;
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ret = cpufreq_frequency_table_cpuinfo(policy, freq_table[cur_cluster]);
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if (ret) {
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dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
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policy->cpu, cur_cluster);
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put_cluster_clk_and_freq_table(cpu_dev);
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return ret;
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}
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cpufreq_frequency_table_get_attr(freq_table[cur_cluster], policy->cpu);
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if (arm_bL_ops->get_transition_latency)
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policy->cpuinfo.transition_latency =
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arm_bL_ops->get_transition_latency(cpu_dev);
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else
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policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
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policy->cur = bL_cpufreq_get(policy->cpu);
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cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
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dev_info(cpu_dev, "CPU %d initialized\n", policy->cpu);
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return 0;
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}
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static int bL_cpufreq_exit(struct cpufreq_policy *policy)
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{
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struct device *cpu_dev;
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cpu_dev = get_cpu_device(policy->cpu);
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if (!cpu_dev) {
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pr_err("%s: failed to get cpu%d device\n", __func__,
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policy->cpu);
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return -ENODEV;
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}
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put_cluster_clk_and_freq_table(cpu_dev);
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dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
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return 0;
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}
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/* Export freq_table to sysfs */
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static struct freq_attr *bL_cpufreq_attr[] = {
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&cpufreq_freq_attr_scaling_available_freqs,
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NULL,
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};
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static struct cpufreq_driver bL_cpufreq_driver = {
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.name = "arm-big-little",
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.flags = CPUFREQ_STICKY,
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.verify = bL_cpufreq_verify_policy,
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.target = bL_cpufreq_set_target,
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.get = bL_cpufreq_get,
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.init = bL_cpufreq_init,
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.exit = bL_cpufreq_exit,
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.have_multiple_policies = true,
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.attr = bL_cpufreq_attr,
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};
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||||||
|
int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
|
||||||
|
{
|
||||||
|
int ret;
|
||||||
|
|
||||||
|
if (arm_bL_ops) {
|
||||||
|
pr_debug("%s: Already registered: %s, exiting\n", __func__,
|
||||||
|
arm_bL_ops->name);
|
||||||
|
return -EBUSY;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
|
||||||
|
pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
|
||||||
|
return -ENODEV;
|
||||||
|
}
|
||||||
|
|
||||||
|
arm_bL_ops = ops;
|
||||||
|
|
||||||
|
ret = cpufreq_register_driver(&bL_cpufreq_driver);
|
||||||
|
if (ret) {
|
||||||
|
pr_info("%s: Failed registering platform driver: %s, err: %d\n",
|
||||||
|
__func__, ops->name, ret);
|
||||||
|
arm_bL_ops = NULL;
|
||||||
|
} else {
|
||||||
|
pr_info("%s: Registered platform driver: %s\n", __func__,
|
||||||
|
ops->name);
|
||||||
|
}
|
||||||
|
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
EXPORT_SYMBOL_GPL(bL_cpufreq_register);
|
||||||
|
|
||||||
|
void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
|
||||||
|
{
|
||||||
|
if (arm_bL_ops != ops) {
|
||||||
|
pr_err("%s: Registered with: %s, can't unregister, exiting\n",
|
||||||
|
__func__, arm_bL_ops->name);
|
||||||
|
return;
|
||||||
|
}
|
||||||
|
|
||||||
|
cpufreq_unregister_driver(&bL_cpufreq_driver);
|
||||||
|
pr_info("%s: Un-registered platform driver: %s\n", __func__,
|
||||||
|
arm_bL_ops->name);
|
||||||
|
arm_bL_ops = NULL;
|
||||||
|
}
|
||||||
|
EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);
|
||||||
|
|
@ -0,0 +1,40 @@
|
||||||
|
/*
|
||||||
|
* ARM big.LITTLE platform's CPUFreq header file
|
||||||
|
*
|
||||||
|
* Copyright (C) 2013 ARM Ltd.
|
||||||
|
* Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
|
||||||
|
*
|
||||||
|
* Copyright (C) 2013 Linaro.
|
||||||
|
* Viresh Kumar <viresh.kumar@linaro.org>
|
||||||
|
*
|
||||||
|
* 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.
|
||||||
|
*
|
||||||
|
* 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.
|
||||||
|
*/
|
||||||
|
#ifndef CPUFREQ_ARM_BIG_LITTLE_H
|
||||||
|
#define CPUFREQ_ARM_BIG_LITTLE_H
|
||||||
|
|
||||||
|
#include <linux/cpufreq.h>
|
||||||
|
#include <linux/device.h>
|
||||||
|
#include <linux/types.h>
|
||||||
|
|
||||||
|
struct cpufreq_arm_bL_ops {
|
||||||
|
char name[CPUFREQ_NAME_LEN];
|
||||||
|
int (*get_transition_latency)(struct device *cpu_dev);
|
||||||
|
|
||||||
|
/*
|
||||||
|
* This must set opp table for cpu_dev in a similar way as done by
|
||||||
|
* of_init_opp_table().
|
||||||
|
*/
|
||||||
|
int (*init_opp_table)(struct device *cpu_dev);
|
||||||
|
};
|
||||||
|
|
||||||
|
int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops);
|
||||||
|
void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops);
|
||||||
|
|
||||||
|
#endif /* CPUFREQ_ARM_BIG_LITTLE_H */
|
||||||
|
|
@ -0,0 +1,92 @@
|
||||||
|
/*
|
||||||
|
* Generic big.LITTLE CPUFreq Interface driver
|
||||||
|
*
|
||||||
|
* It provides necessary ops to arm_big_little cpufreq driver and gets
|
||||||
|
* Frequency information from Device Tree. Freq table in DT must be in KHz.
|
||||||
|
*
|
||||||
|
* Copyright (C) 2013 Linaro.
|
||||||
|
* Viresh Kumar <viresh.kumar@linaro.org>
|
||||||
|
*
|
||||||
|
* 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.
|
||||||
|
*
|
||||||
|
* 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.
|
||||||
|
*/
|
||||||
|
|
||||||
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
||||||
|
|
||||||
|
#include <linux/cpufreq.h>
|
||||||
|
#include <linux/device.h>
|
||||||
|
#include <linux/export.h>
|
||||||
|
#include <linux/module.h>
|
||||||
|
#include <linux/of.h>
|
||||||
|
#include <linux/opp.h>
|
||||||
|
#include <linux/slab.h>
|
||||||
|
#include <linux/types.h>
|
||||||
|
#include "arm_big_little.h"
|
||||||
|
|
||||||
|
static int dt_init_opp_table(struct device *cpu_dev)
|
||||||
|
{
|
||||||
|
struct device_node *np = NULL;
|
||||||
|
int count = 0, ret;
|
||||||
|
|
||||||
|
for_each_child_of_node(of_find_node_by_path("/cpus"), np) {
|
||||||
|
if (count++ != cpu_dev->id)
|
||||||
|
continue;
|
||||||
|
if (!of_get_property(np, "operating-points", NULL))
|
||||||
|
return -ENODATA;
|
||||||
|
|
||||||
|
cpu_dev->of_node = np;
|
||||||
|
|
||||||
|
ret = of_init_opp_table(cpu_dev);
|
||||||
|
if (ret)
|
||||||
|
return ret;
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
return -ENODEV;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int dt_get_transition_latency(struct device *cpu_dev)
|
||||||
|
{
|
||||||
|
struct device_node *np = NULL;
|
||||||
|
u32 transition_latency = CPUFREQ_ETERNAL;
|
||||||
|
int count = 0;
|
||||||
|
|
||||||
|
for_each_child_of_node(of_find_node_by_path("/cpus"), np) {
|
||||||
|
if (count++ != cpu_dev->id)
|
||||||
|
continue;
|
||||||
|
|
||||||
|
of_property_read_u32(np, "clock-latency", &transition_latency);
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
return -ENODEV;
|
||||||
|
}
|
||||||
|
|
||||||
|
static struct cpufreq_arm_bL_ops dt_bL_ops = {
|
||||||
|
.name = "dt-bl",
|
||||||
|
.get_transition_latency = dt_get_transition_latency,
|
||||||
|
.init_opp_table = dt_init_opp_table,
|
||||||
|
};
|
||||||
|
|
||||||
|
static int generic_bL_init(void)
|
||||||
|
{
|
||||||
|
return bL_cpufreq_register(&dt_bL_ops);
|
||||||
|
}
|
||||||
|
module_init(generic_bL_init);
|
||||||
|
|
||||||
|
static void generic_bL_exit(void)
|
||||||
|
{
|
||||||
|
return bL_cpufreq_unregister(&dt_bL_ops);
|
||||||
|
}
|
||||||
|
module_exit(generic_bL_exit);
|
||||||
|
|
||||||
|
MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
|
||||||
|
MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver via DT");
|
||||||
|
MODULE_LICENSE("GPL");
|
||||||
Loading…
Reference in New Issue