cpufreq / highbank: add support for highbank cpufreq
Highbank processors depend on the external ECME to perform voltage management based on a requested frequency. Communication between the A9 cores and the ECME happens over the pl320 IPC channel. Signed-off-by: Mark Langsdorf <mark.langsdorf@calxeda.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> Reviewed-by: Mike Turquette <mturquette@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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@ -37,6 +37,16 @@
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next-level-cache = <&L2>;
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clocks = <&a9pll>;
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clock-names = "cpu";
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operating-points = <
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/* kHz ignored */
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1300000 1000000
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1200000 1000000
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1100000 1000000
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800000 1000000
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400000 1000000
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200000 1000000
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>;
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clock-latency = <100000>;
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};
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cpu@901 {
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@ -1,5 +1,7 @@
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config ARCH_HIGHBANK
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bool "Calxeda ECX-1000/2000 (Highbank/Midway)" if ARCH_MULTI_V7
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select ARCH_HAS_CPUFREQ
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select ARCH_HAS_OPP
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select ARCH_WANT_OPTIONAL_GPIOLIB
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select ARM_AMBA
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select ARM_GIC
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@ -83,3 +83,18 @@ config ARM_SPEAR_CPUFREQ
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default y
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help
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This adds the CPUFreq driver support for SPEAr SOCs.
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config ARM_HIGHBANK_CPUFREQ
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tristate "Calxeda Highbank-based"
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depends on ARCH_HIGHBANK
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select CPU_FREQ_TABLE
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select GENERIC_CPUFREQ_CPU0
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select PM_OPP
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select REGULATOR
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default m
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help
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This adds the CPUFreq driver for Calxeda Highbank SoC
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based boards.
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If in doubt, say N.
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@ -51,8 +51,9 @@ obj-$(CONFIG_ARM_EXYNOS_CPUFREQ) += exynos-cpufreq.o
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obj-$(CONFIG_ARM_EXYNOS4210_CPUFREQ) += exynos4210-cpufreq.o
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obj-$(CONFIG_ARM_EXYNOS4X12_CPUFREQ) += exynos4x12-cpufreq.o
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obj-$(CONFIG_ARM_EXYNOS5250_CPUFREQ) += exynos5250-cpufreq.o
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obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ) += omap-cpufreq.o
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obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ) += omap-cpufreq.o
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obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o
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obj-$(CONFIG_ARM_HIGHBANK_CPUFREQ) += highbank-cpufreq.o
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##################################################################################
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# PowerPC platform drivers
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@ -182,7 +182,11 @@ static int cpu0_cpufreq_driver_init(void)
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struct device_node *np;
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int ret;
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np = of_find_node_by_path("/cpus/cpu@0");
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for_each_child_of_node(of_find_node_by_path("/cpus"), np) {
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if (of_get_property(np, "operating-points", NULL))
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break;
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}
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if (!np) {
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pr_err("failed to find cpu0 node\n");
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return -ENOENT;
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@ -0,0 +1,115 @@
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/*
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* Copyright (C) 2012 Calxeda, Inc.
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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 driver provides the clk notifier callbacks that are used when
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* the cpufreq-cpu0 driver changes to frequency to alert the highbank
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* EnergyCore Management Engine (ECME) about the need to change
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* voltage. The ECME interfaces with the actual voltage regulators.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/clk.h>
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#include <linux/cpu.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/mailbox.h>
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#define HB_CPUFREQ_CHANGE_NOTE 0x80000001
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#define HB_CPUFREQ_IPC_LEN 7
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#define HB_CPUFREQ_VOLT_RETRIES 15
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static int hb_voltage_change(unsigned int freq)
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{
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int i;
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u32 msg[HB_CPUFREQ_IPC_LEN];
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msg[0] = HB_CPUFREQ_CHANGE_NOTE;
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msg[1] = freq / 1000000;
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for (i = 2; i < HB_CPUFREQ_IPC_LEN; i++)
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msg[i] = 0;
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return pl320_ipc_transmit(msg);
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}
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static int hb_cpufreq_clk_notify(struct notifier_block *nb,
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unsigned long action, void *hclk)
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{
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struct clk_notifier_data *clk_data = hclk;
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int i = 0;
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if (action == PRE_RATE_CHANGE) {
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if (clk_data->new_rate > clk_data->old_rate)
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while (hb_voltage_change(clk_data->new_rate))
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if (i++ > HB_CPUFREQ_VOLT_RETRIES)
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return NOTIFY_BAD;
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} else if (action == POST_RATE_CHANGE) {
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if (clk_data->new_rate < clk_data->old_rate)
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while (hb_voltage_change(clk_data->new_rate))
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if (i++ > HB_CPUFREQ_VOLT_RETRIES)
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return NOTIFY_BAD;
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}
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return NOTIFY_DONE;
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}
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static struct notifier_block hb_cpufreq_clk_nb = {
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.notifier_call = hb_cpufreq_clk_notify,
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};
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static int hb_cpufreq_driver_init(void)
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{
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struct device *cpu_dev;
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struct clk *cpu_clk;
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struct device_node *np;
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int ret;
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if (!of_machine_is_compatible("calxeda,highbank"))
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return -ENODEV;
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for_each_child_of_node(of_find_node_by_path("/cpus"), np)
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if (of_get_property(np, "operating-points", NULL))
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break;
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if (!np) {
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pr_err("failed to find highbank cpufreq node\n");
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return -ENOENT;
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}
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cpu_dev = get_cpu_device(0);
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if (!cpu_dev) {
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pr_err("failed to get highbank cpufreq device\n");
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ret = -ENODEV;
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goto out_put_node;
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}
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cpu_dev->of_node = np;
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cpu_clk = clk_get(cpu_dev, NULL);
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if (IS_ERR(cpu_clk)) {
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ret = PTR_ERR(cpu_clk);
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pr_err("failed to get cpu0 clock: %d\n", ret);
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goto out_put_node;
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}
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ret = clk_notifier_register(cpu_clk, &hb_cpufreq_clk_nb);
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if (ret) {
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pr_err("failed to register clk notifier: %d\n", ret);
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goto out_put_node;
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}
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out_put_node:
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of_node_put(np);
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return ret;
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}
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module_init(hb_cpufreq_driver_init);
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MODULE_AUTHOR("Mark Langsdorf <mark.langsdorf@calxeda.com>");
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MODULE_DESCRIPTION("Calxeda Highbank cpufreq driver");
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MODULE_LICENSE("GPL");
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