Hi Viresh,
On mar., déc. 05 2017, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
> On 01-12-17, 12:25, Gregory CLEMENT wrote:
>> This patch adds DVFS support for the Armada 37xx SoCs
>>
>> There are up to four CPU frequency loads for Armada 37xx controlled by
>> the hardware.
>>
>> This driver associates the CPU load level to a frequency, then the
>> hardware will switch while selecting a load level.
>>
>> The hardware also can associate a voltage for each level (AVS support)
>> but it is not yet supported
>>
>> Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
>> ---
>> drivers/cpufreq/Kconfig.arm | 7 +
>> drivers/cpufreq/Makefile | 1 +
>> drivers/cpufreq/armada-37xx-cpufreq.c | 241 ++++++++++++++++++++++++++++++++++
>> 3 files changed, 249 insertions(+)
>> create mode 100644 drivers/cpufreq/armada-37xx-cpufreq.c
>>
>> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
>> index 17625115c67f..3018ff0d068f 100644
>> --- a/drivers/cpufreq/Kconfig.arm
>> +++ b/drivers/cpufreq/Kconfig.arm
>> @@ -19,6 +19,13 @@ config ACPI_CPPC_CPUFREQ
>>
>> If in doubt, say N.
>>
>> +config ARM_ARMADA_37XX_CPUFREQ
>> + tristate "Armada 37xx CPUFreq support"
>> + depends on ARCH_MVEBU
>> + help
>> + This adds the CPUFreq driver support for Marvell Armada 37xx SoCs.
>> + The Armada 37xx PMU supports 4 frequency and VDD levels.
>> +
>> # big LITTLE core layer and glue drivers
>> config ARM_BIG_LITTLE_CPUFREQ
>> tristate "Generic ARM big LITTLE CPUfreq driver"
>> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
>> index d762e76887e7..e07715ce8844 100644
>> --- a/drivers/cpufreq/Makefile
>> +++ b/drivers/cpufreq/Makefile
>> @@ -52,6 +52,7 @@ obj-$(CONFIG_ARM_BIG_LITTLE_CPUFREQ) += arm_big_little.o
>> # LITTLE drivers, so that it is probed last.
>> obj-$(CONFIG_ARM_DT_BL_CPUFREQ) += arm_big_little_dt.o
>>
>> +obj-$(CONFIG_ARM_ARMADA_37XX_CPUFREQ) += armada-37xx-cpufreq.o
>> obj-$(CONFIG_ARM_BRCMSTB_AVS_CPUFREQ) += brcmstb-avs-cpufreq.o
>> obj-$(CONFIG_ACPI_CPPC_CPUFREQ) += cppc_cpufreq.o
>> obj-$(CONFIG_ARCH_DAVINCI) += davinci-cpufreq.o
>> diff --git a/drivers/cpufreq/armada-37xx-cpufreq.c b/drivers/cpufreq/armada-37xx-cpufreq.c
>> new file mode 100644
>> index 000000000000..40c9a744cc6e
>> --- /dev/null
>> +++ b/drivers/cpufreq/armada-37xx-cpufreq.c
>> @@ -0,0 +1,241 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * CPU frequency scaling support for Armada 37xx platform.
>> + *
>> + * Copyright (C) 2017 Marvell
>> + *
>> + * Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/cpu.h>
>> +#include <linux/cpufreq.h>
>> +#include <linux/err.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/io.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/module.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_device.h>
>> +#include <linux/of_irq.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm_opp.h>
>> +#include <linux/regmap.h>
>> +#include <linux/slab.h>
>> +
>> +/* Power management in North Bridge register set */
>> +#define ARMADA_37XX_NB_L0L1 0x18
>> +#define ARMADA_37XX_NB_L2L3 0x1C
>> +#define ARMADA_37XX_NB_TBG_DIV_OFF 13
>> +#define ARMADA_37XX_NB_TBG_DIV_MASK 0x7
>> +#define ARMADA_37XX_NB_CLK_SEL_OFF 11
>> +#define ARMADA_37XX_NB_CLK_SEL_MASK 0x1
>> +#define ARMADA_37XX_NB_CLK_SEL_TBG 0x1
>> +#define ARMADA_37XX_NB_TBG_SEL_OFF 9
>> +#define ARMADA_37XX_NB_TBG_SEL_MASK 0x3
>> +#define ARMADA_37XX_NB_VDD_SEL_OFF 6
>> +#define ARMADA_37XX_NB_VDD_SEL_MASK 0x3
>> +#define ARMADA_37XX_NB_CONFIG_SHIFT 16
>
> Looks like you have added tabs after #define as well? Perhaps a space
> is good enough there.
OK
>
>> +#define ARMADA_37XX_NB_DYN_MOD 0x24
>> +#define ARMADA_37XX_NB_CLK_SEL_EN BIT(26)
>> +#define ARMADA_37XX_NB_TBG_EN BIT(28)
>> +#define ARMADA_37XX_NB_DIV_EN BIT(29)
>> +#define ARMADA_37XX_NB_VDD_EN BIT(30)
>> +#define ARMADA_37XX_NB_DFS_EN BIT(31)
>> +#define ARMADA_37XX_NB_CPU_LOAD 0x30
>> +#define ARMADA_37XX_NB_CPU_LOAD_MASK 0x3
>> +#define ARMADA_37XX_DVFS_LOAD_0 0
>> +#define ARMADA_37XX_DVFS_LOAD_1 1
>> +#define ARMADA_37XX_DVFS_LOAD_2 2
>> +#define ARMADA_37XX_DVFS_LOAD_3 3
>> +
>> +/*
>> + * On Armada 37xx the Power management manages 4 level of CPU load,
>> + * each level can be associated with a CPU clock source, a CPU
>> + * divider, a VDD level, etc...
>> + */
>> +#define LOAD_LEVEL_NR 4
>> +
>> +struct armada_37xx_dvfs {
>> + u32 cpu_freq_max;
>> + u8 divider[LOAD_LEVEL_NR];
>> +};
>> +
>> +static struct armada_37xx_dvfs armada_37xx_dvfs[] = {
>> + {.cpu_freq_max = 1200*1000*1000, .divider = {1, 2, 4, 6} },
>> + {.cpu_freq_max = 1000*1000*1000, .divider = {1, 2, 4, 5} },
>> + {.cpu_freq_max = 800*1000*1000, .divider = {1, 2, 3, 4} },
>> + {.cpu_freq_max = 600*1000*1000, .divider = {2, 4, 5, 6} },
>> +};
>> +
>> +static struct armada_37xx_dvfs *armada_37xx_cpu_freq_info_get(u32 freq)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < ARRAY_SIZE(armada_37xx_dvfs); i++) {
>> + if (freq == armada_37xx_dvfs[i].cpu_freq_max)
>> + return &armada_37xx_dvfs[i];
>> + }
>> +
>> + pr_err("Unsupported CPU frequency %d MHz\n", freq/1000000);
>> + return NULL;
>> +}
>> +
>> +/*
>> + * Setup the four level managed by the hardware. Once the four level
>> + * will be configured then the DVFS will be enabled.
>> + */
>> +static void __init armada37xx_cpufreq_dvfs_setup(struct regmap *base,
>> + struct clk *clk, u8 *divider)
>> +{
>> + int load_level;
>> + struct clk *parent;
>> +
>> + for (load_level = 0; load_level < LOAD_LEVEL_NR; load_level++) {
>> + unsigned int reg, mask, val, offset = 0;
>> +
>> + if (load_level <= ARMADA_37XX_DVFS_LOAD_1)
>> + reg = ARMADA_37XX_NB_L0L1;
>> + else
>> + reg = ARMADA_37XX_NB_L2L3;
>> +
>> + if (load_level == ARMADA_37XX_DVFS_LOAD_0 ||
>> + load_level == ARMADA_37XX_DVFS_LOAD_2)
>> + offset += ARMADA_37XX_NB_CONFIG_SHIFT;
>> +
>> + /* Set cpu clock source, for all the level we use TBG */
>> + val = ARMADA_37XX_NB_CLK_SEL_TBG << ARMADA_37XX_NB_CLK_SEL_OFF;
>> + mask = (ARMADA_37XX_NB_CLK_SEL_MASK
>> + << ARMADA_37XX_NB_CLK_SEL_OFF);
>> +
>> + /*
>> + * Set cpu divider based on the pre-computed array in
>> + * order to have balanced step.
>> + */
>> + val |= divider[load_level] << ARMADA_37XX_NB_TBG_DIV_OFF;
>> + mask |= (ARMADA_37XX_NB_TBG_DIV_MASK
>> + << ARMADA_37XX_NB_TBG_DIV_OFF);
>> +
>> + /* Set VDD divider which is actually the load level. */
>> + val |= load_level << ARMADA_37XX_NB_VDD_SEL_OFF;
>> + mask |= (ARMADA_37XX_NB_VDD_SEL_MASK
>> + << ARMADA_37XX_NB_VDD_SEL_OFF);
>> +
>> + val <<= offset;
>> + mask <<= offset;
>> +
>> + regmap_update_bits(base, reg, mask, val);
>> + }
>> +
>> + /*
>> + * Set cpu clock source, for all the level we keep the same
>> + * clock source that the one already configured. For this one
>> + * we need to use the clock framework
>> + */
>> + parent = clk_get_parent(clk);
>> + clk_set_parent(clk, parent);
>> +}
>> +
>> +static void __init armada37xx_cpufreq_disable_dvfs(struct regmap *base)
>> +{
>> + unsigned int reg = ARMADA_37XX_NB_DYN_MOD,
>> + mask = ARMADA_37XX_NB_DFS_EN;
>> +
>> + regmap_update_bits(base, reg, mask, 0);
>> +}
>> +
>> +static void __init armada37xx_cpufreq_enable_dvfs(struct regmap *base)
>> +{
>> + unsigned int val, reg = ARMADA_37XX_NB_CPU_LOAD,
>> + mask = ARMADA_37XX_NB_CPU_LOAD_MASK;
>> +
>> + /* Start with the highest load (0) */
>> + val = ARMADA_37XX_DVFS_LOAD_0;
>> + regmap_update_bits(base, reg, mask, val);
>> +
>> + /* Now enable DVFS for the CPUs */
>> + reg = ARMADA_37XX_NB_DYN_MOD;
>> + mask = ARMADA_37XX_NB_CLK_SEL_EN | ARMADA_37XX_NB_TBG_EN |
>> + ARMADA_37XX_NB_DIV_EN | ARMADA_37XX_NB_VDD_EN |
>> + ARMADA_37XX_NB_DFS_EN;
>> +
>> + regmap_update_bits(base, reg, mask, mask);
>> +}
>> +
>> +static int __init armada37xx_cpufreq_driver_init(void)
>> +{
>> + struct armada_37xx_dvfs *dvfs;
>> + struct platform_device *pdev;
>> + unsigned int cur_frequency;
>> + struct regmap *nb_pm_base;
>> + struct device *cpu_dev;
>> + int load_level, ret;
>> + struct clk *clk;
>> +
>> + nb_pm_base =
>> + syscon_regmap_lookup_by_compatible("marvell,armada-3700-nb-pm");
>> +
>> + if (IS_ERR(nb_pm_base))
>> + return -ENODEV;
>> +
>> + /* Before doing any configuration on the DVFS first, disable it */
>> + armada37xx_cpufreq_disable_dvfs(nb_pm_base);
>> +
>> + /*
>> + * On CPU 0 register the operating points supported (which are
>> + * the nominal CPU frequency and full integer divisions of
>> + * it).
>> + */
>> + cpu_dev = get_cpu_device(0);
>> + if (!cpu_dev) {
>> + dev_err(cpu_dev, "Cannot get CPU\n");
>> + return -ENODEV;
>> + }
>> +
>> + clk = clk_get(cpu_dev, 0);
>> + if (IS_ERR(clk)) {
>> + dev_err(cpu_dev, "Cannot get clock for CPU0\n");
>> + return PTR_ERR(clk);
>> + }
>> +
>> + /* Get nominal (current) CPU frequency */
>> + cur_frequency = clk_get_rate(clk);
>> + if (!cur_frequency) {
>> + dev_err(cpu_dev, "Failed to get clock rate for CPU\n");
>> + return -EINVAL;
>> + }
>> +
>> + dvfs = armada_37xx_cpu_freq_info_get(cur_frequency);
>> + if (!dvfs)
>> + return -EINVAL;
>> +
>> + armada37xx_cpufreq_dvfs_setup(nb_pm_base, clk, dvfs->divider);
>> +
>> + /*
>> + * 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),
>
> What do you mean by the comment within ()? We do have
> dev_pm_opp_remove() helper.
Actually it was a copy and paste from an other driver, I didn't check it
this was still true.
So the original comment was added in July 2014 and the
dev_pm_opp_remove() helpers was added few months later
in Nov 2014.
I will fix it and also in the other driver mvebu-cpufreq.c.
Thanks,
Gregory
>
>> and simply cancel the registration of the cpufreq
>> + * device.
>> + */
>> + for (load_level = ARMADA_37XX_DVFS_LOAD_0; load_level < LOAD_LEVEL_NR;
>> + load_level++) {
>> + unsigned long freq = dvfs->divider[load_level];
>> +
>> + ret = dev_pm_opp_add(cpu_dev, freq, 0);
>> + if (ret)
>> + return ret;
>> + }
>> +
>> + /* Now that everything is setup, enable the DVFS at hardware level */
>> + armada37xx_cpufreq_enable_dvfs(nb_pm_base);
>> +
>> + pdev = platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
>> +
>> + return PTR_ERR_OR_ZERO(pdev);
>> +}
>> +/* late_initcall, to guarantee the driver is loaded after A37xx clock driver */
>> +late_initcall(armada37xx_cpufreq_driver_init);
>> +
>> +MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>");
>> +MODULE_DESCRIPTION("Armada 37xx cpufreq driver");
>> +MODULE_LICENSE("GPL");
>> --
>> 2.15.0
>
> --
> viresh
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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