From 831e2518890f5ffd52706750b1cbf04feb2e7c59 Mon Sep 17 00:00:00 2001 From: Thomas Petazzoni Date: Wed, 9 Jul 2014 17:45:09 +0200 Subject: ARM: mvebu: ensure CPU clocks are enabled In the Armada XP SMP support code, we are reading the clock frequency of the booting CPU, and use that to assign the same frequency to the other CPUs, and we do this while the clocks are disabled. However, the CPU clocks are in fact never prepared/enabled, and to support cpufreq, we now have two code paths to change the frequency of the CPU clocks in the CPU clock driver: one when the clock is enabled (dynamic frequency scaling), one when the clock is disabled (adjusting the CPU frequency before starting the CPU). In order for this to work, the CPU clocks now have to be prepared and enabled after the initial synchronization of the clock frequencies is done, so that all future rate changes of the CPU clocks will trigger a dynamic frequency scaling transition. Signed-off-by: Thomas Petazzoni Link: https://lkml.kernel.org/r/1404920715-19834-2-git-send-email-thomas.petazzoni@free-electrons.com Signed-off-by: Jason Cooper --- arch/arm/mach-mvebu/platsmp.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/arm/mach-mvebu') diff --git a/arch/arm/mach-mvebu/platsmp.c b/arch/arm/mach-mvebu/platsmp.c index 88b976b31719..4880b0f70362 100644 --- a/arch/arm/mach-mvebu/platsmp.c +++ b/arch/arm/mach-mvebu/platsmp.c @@ -67,6 +67,7 @@ static void __init set_secondary_cpus_clock(void) if (!cpu_clk) return; clk_set_rate(cpu_clk, rate); + clk_prepare_enable(cpu_clk); } } -- cgit v1.2.3 From a509ea840b8e29e512764803e30b805c7ea89038 Mon Sep 17 00:00:00 2001 From: Thomas Petazzoni Date: Wed, 9 Jul 2014 17:45:10 +0200 Subject: ARM: mvebu: extend PMSU code to support dynamic frequency scaling This commit adds the necessary code in the Marvell EBU PMSU driver to support dynamic frequency scaling. In essence, what this new code does is that it: * registers the frequency operating points supported by the CPU; * registers a clock notifier of the CPU clocks. The notifier function listens to the newly introduced APPLY_RATE_CHANGE event, and uses that to finalize the frequency transition by doing the part of the procedure that involves the PMSU; * registers a platform device for the cpufreq-generic driver, which will take care of the CPU frequency transitions. Signed-off-by: Thomas Petazzoni Link: https://lkml.kernel.org/r/1404920715-19834-3-git-send-email-thomas.petazzoni@free-electrons.com Signed-off-by: Jason Cooper --- arch/arm/mach-mvebu/pmsu.c | 162 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/mvebu-pmsu.h | 20 ++++++ 2 files changed, 182 insertions(+) create mode 100644 include/linux/mvebu-pmsu.h (limited to 'arch/arm/mach-mvebu') diff --git a/arch/arm/mach-mvebu/pmsu.c b/arch/arm/mach-mvebu/pmsu.c index 53a55c8520bf..db7d9ab298b6 100644 --- a/arch/arm/mach-mvebu/pmsu.c +++ b/arch/arm/mach-mvebu/pmsu.c @@ -18,20 +18,26 @@ #define pr_fmt(fmt) "mvebu-pmsu: " fmt +#include #include +#include #include #include #include +#include #include #include +#include #include #include +#include #include #include #include #include #include #include "common.h" +#include "armada-370-xp.h" static void __iomem *pmsu_mp_base; @@ -57,6 +63,10 @@ static void __iomem *pmsu_mp_base; #define PMSU_STATUS_AND_MASK_IRQ_MASK BIT(24) #define PMSU_STATUS_AND_MASK_FIQ_MASK BIT(25) +#define PMSU_EVENT_STATUS_AND_MASK(cpu) ((cpu * 0x100) + 0x120) +#define PMSU_EVENT_STATUS_AND_MASK_DFS_DONE BIT(1) +#define PMSU_EVENT_STATUS_AND_MASK_DFS_DONE_MASK BIT(17) + #define PMSU_BOOT_ADDR_REDIRECT_OFFSET(cpu) ((cpu * 0x100) + 0x124) /* PMSU fabric registers */ @@ -296,3 +306,155 @@ int __init armada_370_xp_cpu_pm_init(void) arch_initcall(armada_370_xp_cpu_pm_init); early_initcall(armada_370_xp_pmsu_init); + +static void mvebu_pmsu_dfs_request_local(void *data) +{ + u32 reg; + u32 cpu = smp_processor_id(); + unsigned long flags; + + local_irq_save(flags); + + /* Prepare to enter idle */ + reg = readl(pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu)); + reg |= PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT | + PMSU_STATUS_AND_MASK_IRQ_MASK | + PMSU_STATUS_AND_MASK_FIQ_MASK; + writel(reg, pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu)); + + /* Request the DFS transition */ + reg = readl(pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(cpu)); + reg |= PMSU_CONTROL_AND_CONFIG_DFS_REQ; + writel(reg, pmsu_mp_base + PMSU_CONTROL_AND_CONFIG(cpu)); + + /* The fact of entering idle will trigger the DFS transition */ + wfi(); + + /* + * We're back from idle, the DFS transition has completed, + * clear the idle wait indication. + */ + reg = readl(pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu)); + reg &= ~PMSU_STATUS_AND_MASK_CPU_IDLE_WAIT; + writel(reg, pmsu_mp_base + PMSU_STATUS_AND_MASK(cpu)); + + local_irq_restore(flags); +} + +int mvebu_pmsu_dfs_request(int cpu) +{ + unsigned long timeout; + int hwcpu = cpu_logical_map(cpu); + u32 reg; + + /* Clear any previous DFS DONE event */ + reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu)); + reg &= ~PMSU_EVENT_STATUS_AND_MASK_DFS_DONE; + writel(reg, pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu)); + + /* Mask the DFS done interrupt, since we are going to poll */ + reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu)); + reg |= PMSU_EVENT_STATUS_AND_MASK_DFS_DONE_MASK; + writel(reg, pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu)); + + /* Trigger the DFS on the appropriate CPU */ + smp_call_function_single(cpu, mvebu_pmsu_dfs_request_local, + NULL, false); + + /* Poll until the DFS done event is generated */ + timeout = jiffies + HZ; + while (time_before(jiffies, timeout)) { + reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu)); + if (reg & PMSU_EVENT_STATUS_AND_MASK_DFS_DONE) + break; + udelay(10); + } + + if (time_after(jiffies, timeout)) + return -ETIME; + + /* Restore the DFS mask to its original state */ + reg = readl(pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu)); + reg &= ~PMSU_EVENT_STATUS_AND_MASK_DFS_DONE_MASK; + writel(reg, pmsu_mp_base + PMSU_EVENT_STATUS_AND_MASK(hwcpu)); + + return 0; +} + +static int __init armada_xp_pmsu_cpufreq_init(void) +{ + struct device_node *np; + struct resource res; + int ret, cpu; + + if (!of_machine_is_compatible("marvell,armadaxp")) + return 0; + + /* + * In order to have proper cpufreq handling, we need to ensure + * that the Device Tree description of the CPU clock includes + * the definition of the PMU DFS registers. If not, we do not + * register the clock notifier and the cpufreq driver. This + * piece of code is only for compatibility with old Device + * Trees. + */ + np = of_find_compatible_node(NULL, NULL, "marvell,armada-xp-cpu-clock"); + if (!np) + return 0; + + ret = of_address_to_resource(np, 1, &res); + if (ret) { + pr_warn(FW_WARN "not enabling cpufreq, deprecated armada-xp-cpu-clock binding\n"); + of_node_put(np); + return 0; + } + + of_node_put(np); + + /* + * For each CPU, this loop registers the operating points + * supported (which are the nominal CPU frequency and half of + * it), and registers the clock notifier that will take care + * of doing the PMSU part of a frequency transition. + */ + for_each_possible_cpu(cpu) { + struct device *cpu_dev; + struct clk *clk; + int ret; + + cpu_dev = get_cpu_device(cpu); + if (!cpu_dev) { + pr_err("Cannot get CPU %d\n", cpu); + continue; + } + + clk = clk_get(cpu_dev, 0); + if (!clk) { + pr_err("Cannot get clock for CPU %d\n", cpu); + return -ENODEV; + } + + /* + * In case of a failure of dev_pm_opp_add(), we don't + * bother with cleaning up the registered OPP (there's + * no function to do so), and simply cancel the + * registration of the cpufreq device. + */ + ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk), 0); + if (ret) { + clk_put(clk); + return ret; + } + + ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk) / 2, 0); + if (ret) { + clk_put(clk); + return ret; + } + } + + platform_device_register_simple("cpufreq-generic", -1, NULL, 0); + return 0; +} + +device_initcall(armada_xp_pmsu_cpufreq_init); diff --git a/include/linux/mvebu-pmsu.h b/include/linux/mvebu-pmsu.h new file mode 100644 index 000000000000..b918d07efe23 --- /dev/null +++ b/include/linux/mvebu-pmsu.h @@ -0,0 +1,20 @@ +/* + * Copyright (C) 2012 Marvell + * + * Thomas Petazzoni + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#ifndef __MVEBU_PMSU_H__ +#define __MVEBU_PMSU_H__ + +#ifdef CONFIG_MACH_MVEBU_V7 +int mvebu_pmsu_dfs_request(int cpu); +#else +static inline int mvebu_pmsu_dfs_request(int cpu) { return -ENODEV; } +#endif + +#endif /* __MVEBU_PMSU_H__ */ -- cgit v1.2.3