diff options
Diffstat (limited to 'drivers/cpufreq/armada-37xx-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/armada-37xx-cpufreq.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/drivers/cpufreq/armada-37xx-cpufreq.c b/drivers/cpufreq/armada-37xx-cpufreq.c new file mode 100644 index 000000000000..c6ebc88a7d8d --- /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@free-electrons.com> + */ + +#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 +#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_lvl; + struct clk *parent; + + for (load_lvl = 0; load_lvl < LOAD_LEVEL_NR; load_lvl++) { + unsigned int reg, mask, val, offset = 0; + + if (load_lvl <= ARMADA_37XX_DVFS_LOAD_1) + reg = ARMADA_37XX_NB_L0L1; + else + reg = ARMADA_37XX_NB_L2L3; + + if (load_lvl == ARMADA_37XX_DVFS_LOAD_0 || + load_lvl == 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_lvl] << 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_lvl << 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_lvl, 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); + + for (load_lvl = ARMADA_37XX_DVFS_LOAD_0; load_lvl < LOAD_LEVEL_NR; + load_lvl++) { + unsigned long freq = cur_frequency / dvfs->divider[load_lvl]; + + ret = dev_pm_opp_add(cpu_dev, freq, 0); + if (ret) { + /* clean-up the already added opp before leaving */ + while (load_lvl-- > ARMADA_37XX_DVFS_LOAD_0) { + freq = cur_frequency / dvfs->divider[load_lvl]; + dev_pm_opp_remove(cpu_dev, freq); + } + 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@free-electrons.com>"); +MODULE_DESCRIPTION("Armada 37xx cpufreq driver"); +MODULE_LICENSE("GPL"); |