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.
> +#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.
> 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
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