diff options
Diffstat (limited to 'drivers/cpufreq/armada-37xx-cpufreq.c')
-rw-r--r-- | drivers/cpufreq/armada-37xx-cpufreq.c | 562 |
1 files changed, 562 insertions, 0 deletions
diff --git a/drivers/cpufreq/armada-37xx-cpufreq.c b/drivers/cpufreq/armada-37xx-cpufreq.c new file mode 100644 index 0000000000..bea41ccabf --- /dev/null +++ b/drivers/cpufreq/armada-37xx-cpufreq.c @@ -0,0 +1,562 @@ +// 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/mod_devicetable.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pm_opp.h> +#include <linux/regmap.h> +#include <linux/slab.h> + +#include "cpufreq-dt.h" + +/* Clk register set */ +#define ARMADA_37XX_CLK_TBG_SEL 0 +#define ARMADA_37XX_CLK_TBG_SEL_CPU_OFF 22 + +/* 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 + +/* AVS register set */ +#define ARMADA_37XX_AVS_CTL0 0x0 +#define ARMADA_37XX_AVS_ENABLE BIT(30) +#define ARMADA_37XX_AVS_HIGH_VDD_LIMIT 16 +#define ARMADA_37XX_AVS_LOW_VDD_LIMIT 22 +#define ARMADA_37XX_AVS_VDD_MASK 0x3F +#define ARMADA_37XX_AVS_CTL2 0x8 +#define ARMADA_37XX_AVS_LOW_VDD_EN BIT(6) +#define ARMADA_37XX_AVS_VSET(x) (0x1C + 4 * (x)) + +/* + * 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 + +#define MIN_VOLT_MV 1000 +#define MIN_VOLT_MV_FOR_L1_1000MHZ 1108 +#define MIN_VOLT_MV_FOR_L1_1200MHZ 1155 + +/* AVS value for the corresponding voltage (in mV) */ +static int avs_map[] = { + 747, 758, 770, 782, 793, 805, 817, 828, 840, 852, 863, 875, 887, 898, + 910, 922, 933, 945, 957, 968, 980, 992, 1003, 1015, 1027, 1038, 1050, + 1062, 1073, 1085, 1097, 1108, 1120, 1132, 1143, 1155, 1167, 1178, 1190, + 1202, 1213, 1225, 1237, 1248, 1260, 1272, 1283, 1295, 1307, 1318, 1330, + 1342 +}; + +struct armada37xx_cpufreq_state { + struct platform_device *pdev; + struct device *cpu_dev; + struct regmap *regmap; + u32 nb_l0l1; + u32 nb_l2l3; + u32 nb_dyn_mod; + u32 nb_cpu_load; +}; + +static struct armada37xx_cpufreq_state *armada37xx_cpufreq_state; + +struct armada_37xx_dvfs { + u32 cpu_freq_max; + u8 divider[LOAD_LEVEL_NR]; + u32 avs[LOAD_LEVEL_NR]; +}; + +static struct armada_37xx_dvfs armada_37xx_dvfs[] = { + /* + * The cpufreq scaling for 1.2 GHz variant of the SOC is currently + * unstable because we do not know how to configure it properly. + */ + /* {.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 regmap *clk_base, u8 *divider) +{ + u32 cpu_tbg_sel; + int load_lvl; + + /* Determine to which TBG clock is CPU connected */ + regmap_read(clk_base, ARMADA_37XX_CLK_TBG_SEL, &cpu_tbg_sel); + cpu_tbg_sel >>= ARMADA_37XX_CLK_TBG_SEL_CPU_OFF; + cpu_tbg_sel &= ARMADA_37XX_NB_TBG_SEL_MASK; + + 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 TBG index, for all levels we use the same TBG */ + val = cpu_tbg_sel << ARMADA_37XX_NB_TBG_SEL_OFF; + mask = (ARMADA_37XX_NB_TBG_SEL_MASK + << ARMADA_37XX_NB_TBG_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); + } +} + +/* + * Find out the armada 37x supported AVS value whose voltage value is + * the round-up closest to the target voltage value. + */ +static u32 armada_37xx_avs_val_match(int target_vm) +{ + u32 avs; + + /* Find out the round-up closest supported voltage value */ + for (avs = 0; avs < ARRAY_SIZE(avs_map); avs++) + if (avs_map[avs] >= target_vm) + break; + + /* + * If all supported voltages are smaller than target one, + * choose the largest supported voltage + */ + if (avs == ARRAY_SIZE(avs_map)) + avs = ARRAY_SIZE(avs_map) - 1; + + return avs; +} + +/* + * For Armada 37xx soc, L0(VSET0) VDD AVS value is set to SVC revision + * value or a default value when SVC is not supported. + * - L0 can be read out from the register of AVS_CTRL_0 and L0 voltage + * can be got from the mapping table of avs_map. + * - L1 voltage should be about 100mv smaller than L0 voltage + * - L2 & L3 voltage should be about 150mv smaller than L0 voltage. + * This function calculates L1 & L2 & L3 AVS values dynamically based + * on L0 voltage and fill all AVS values to the AVS value table. + * When base CPU frequency is 1000 or 1200 MHz then there is additional + * minimal avs value for load L1. + */ +static void __init armada37xx_cpufreq_avs_configure(struct regmap *base, + struct armada_37xx_dvfs *dvfs) +{ + unsigned int target_vm; + int load_level = 0; + u32 l0_vdd_min; + + if (base == NULL) + return; + + /* Get L0 VDD min value */ + regmap_read(base, ARMADA_37XX_AVS_CTL0, &l0_vdd_min); + l0_vdd_min = (l0_vdd_min >> ARMADA_37XX_AVS_LOW_VDD_LIMIT) & + ARMADA_37XX_AVS_VDD_MASK; + if (l0_vdd_min >= ARRAY_SIZE(avs_map)) { + pr_err("L0 VDD MIN %d is not correct.\n", l0_vdd_min); + return; + } + dvfs->avs[0] = l0_vdd_min; + + if (avs_map[l0_vdd_min] <= MIN_VOLT_MV) { + /* + * If L0 voltage is smaller than 1000mv, then all VDD sets + * use L0 voltage; + */ + u32 avs_min = armada_37xx_avs_val_match(MIN_VOLT_MV); + + for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++) + dvfs->avs[load_level] = avs_min; + + /* + * Set the avs values for load L0 and L1 when base CPU frequency + * is 1000/1200 MHz to its typical initial values according to + * the Armada 3700 Hardware Specifications. + */ + if (dvfs->cpu_freq_max >= 1000*1000*1000) { + if (dvfs->cpu_freq_max >= 1200*1000*1000) + avs_min = armada_37xx_avs_val_match(MIN_VOLT_MV_FOR_L1_1200MHZ); + else + avs_min = armada_37xx_avs_val_match(MIN_VOLT_MV_FOR_L1_1000MHZ); + dvfs->avs[0] = dvfs->avs[1] = avs_min; + } + + return; + } + + /* + * L1 voltage is equal to L0 voltage - 100mv and it must be + * larger than 1000mv + */ + + target_vm = avs_map[l0_vdd_min] - 100; + target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV; + dvfs->avs[1] = armada_37xx_avs_val_match(target_vm); + + /* + * L2 & L3 voltage is equal to L0 voltage - 150mv and it must + * be larger than 1000mv + */ + target_vm = avs_map[l0_vdd_min] - 150; + target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV; + dvfs->avs[2] = dvfs->avs[3] = armada_37xx_avs_val_match(target_vm); + + /* + * Fix the avs value for load L1 when base CPU frequency is 1000/1200 MHz, + * otherwise the CPU gets stuck when switching from load L1 to load L0. + * Also ensure that avs value for load L1 is not higher than for L0. + */ + if (dvfs->cpu_freq_max >= 1000*1000*1000) { + u32 avs_min_l1; + + if (dvfs->cpu_freq_max >= 1200*1000*1000) + avs_min_l1 = armada_37xx_avs_val_match(MIN_VOLT_MV_FOR_L1_1200MHZ); + else + avs_min_l1 = armada_37xx_avs_val_match(MIN_VOLT_MV_FOR_L1_1000MHZ); + + if (avs_min_l1 > dvfs->avs[0]) + avs_min_l1 = dvfs->avs[0]; + + if (dvfs->avs[1] < avs_min_l1) + dvfs->avs[1] = avs_min_l1; + } +} + +static void __init armada37xx_cpufreq_avs_setup(struct regmap *base, + struct armada_37xx_dvfs *dvfs) +{ + unsigned int avs_val = 0; + int load_level = 0; + + if (base == NULL) + return; + + /* Disable AVS before the configuration */ + regmap_update_bits(base, ARMADA_37XX_AVS_CTL0, + ARMADA_37XX_AVS_ENABLE, 0); + + + /* Enable low voltage mode */ + regmap_update_bits(base, ARMADA_37XX_AVS_CTL2, + ARMADA_37XX_AVS_LOW_VDD_EN, + ARMADA_37XX_AVS_LOW_VDD_EN); + + + for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++) { + avs_val = dvfs->avs[load_level]; + regmap_update_bits(base, ARMADA_37XX_AVS_VSET(load_level-1), + ARMADA_37XX_AVS_VDD_MASK << ARMADA_37XX_AVS_HIGH_VDD_LIMIT | + ARMADA_37XX_AVS_VDD_MASK << ARMADA_37XX_AVS_LOW_VDD_LIMIT, + avs_val << ARMADA_37XX_AVS_HIGH_VDD_LIMIT | + avs_val << ARMADA_37XX_AVS_LOW_VDD_LIMIT); + } + + /* Enable AVS after the configuration */ + regmap_update_bits(base, ARMADA_37XX_AVS_CTL0, + ARMADA_37XX_AVS_ENABLE, + ARMADA_37XX_AVS_ENABLE); + +} + +static void 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 armada37xx_cpufreq_suspend(struct cpufreq_policy *policy) +{ + struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state; + + regmap_read(state->regmap, ARMADA_37XX_NB_L0L1, &state->nb_l0l1); + regmap_read(state->regmap, ARMADA_37XX_NB_L2L3, &state->nb_l2l3); + regmap_read(state->regmap, ARMADA_37XX_NB_CPU_LOAD, + &state->nb_cpu_load); + regmap_read(state->regmap, ARMADA_37XX_NB_DYN_MOD, &state->nb_dyn_mod); + + return 0; +} + +static int armada37xx_cpufreq_resume(struct cpufreq_policy *policy) +{ + struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state; + + /* Ensure DVFS is disabled otherwise the following registers are RO */ + armada37xx_cpufreq_disable_dvfs(state->regmap); + + regmap_write(state->regmap, ARMADA_37XX_NB_L0L1, state->nb_l0l1); + regmap_write(state->regmap, ARMADA_37XX_NB_L2L3, state->nb_l2l3); + regmap_write(state->regmap, ARMADA_37XX_NB_CPU_LOAD, + state->nb_cpu_load); + + /* + * NB_DYN_MOD register is the one that actually enable back DVFS if it + * was enabled before the suspend operation. This must be done last + * otherwise other registers are not writable. + */ + regmap_write(state->regmap, ARMADA_37XX_NB_DYN_MOD, state->nb_dyn_mod); + + return 0; +} + +static int __init armada37xx_cpufreq_driver_init(void) +{ + struct cpufreq_dt_platform_data pdata; + struct armada_37xx_dvfs *dvfs; + struct platform_device *pdev; + unsigned long freq; + unsigned int base_frequency; + struct regmap *nb_clk_base, *nb_pm_base, *avs_base; + struct device *cpu_dev; + int load_lvl, ret; + struct clk *clk, *parent; + + nb_clk_base = + syscon_regmap_lookup_by_compatible("marvell,armada-3700-periph-clock-nb"); + if (IS_ERR(nb_clk_base)) + return -ENODEV; + + nb_pm_base = + syscon_regmap_lookup_by_compatible("marvell,armada-3700-nb-pm"); + + if (IS_ERR(nb_pm_base)) + return -ENODEV; + + avs_base = + syscon_regmap_lookup_by_compatible("marvell,armada-3700-avs"); + + /* if AVS is not present don't use it but still try to setup dvfs */ + if (IS_ERR(avs_base)) { + pr_info("Syscon failed for Adapting Voltage Scaling: skip it\n"); + avs_base = NULL; + } + /* 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, NULL); + if (IS_ERR(clk)) { + dev_err(cpu_dev, "Cannot get clock for CPU0\n"); + return PTR_ERR(clk); + } + + parent = clk_get_parent(clk); + if (IS_ERR(parent)) { + dev_err(cpu_dev, "Cannot get parent clock for CPU0\n"); + clk_put(clk); + return PTR_ERR(parent); + } + + /* Get parent CPU frequency */ + base_frequency = clk_get_rate(parent); + + if (!base_frequency) { + dev_err(cpu_dev, "Failed to get parent clock rate for CPU\n"); + clk_put(clk); + return -EINVAL; + } + + dvfs = armada_37xx_cpu_freq_info_get(base_frequency); + if (!dvfs) { + clk_put(clk); + return -EINVAL; + } + + armada37xx_cpufreq_state = kmalloc(sizeof(*armada37xx_cpufreq_state), + GFP_KERNEL); + if (!armada37xx_cpufreq_state) { + clk_put(clk); + return -ENOMEM; + } + + armada37xx_cpufreq_state->regmap = nb_pm_base; + + armada37xx_cpufreq_avs_configure(avs_base, dvfs); + armada37xx_cpufreq_avs_setup(avs_base, dvfs); + + armada37xx_cpufreq_dvfs_setup(nb_pm_base, nb_clk_base, dvfs->divider); + clk_put(clk); + + for (load_lvl = ARMADA_37XX_DVFS_LOAD_0; load_lvl < LOAD_LEVEL_NR; + load_lvl++) { + unsigned long u_volt = avs_map[dvfs->avs[load_lvl]] * 1000; + freq = base_frequency / dvfs->divider[load_lvl]; + ret = dev_pm_opp_add(cpu_dev, freq, u_volt); + if (ret) + goto remove_opp; + + + } + + /* Now that everything is setup, enable the DVFS at hardware level */ + armada37xx_cpufreq_enable_dvfs(nb_pm_base); + + memset(&pdata, 0, sizeof(pdata)); + pdata.suspend = armada37xx_cpufreq_suspend; + pdata.resume = armada37xx_cpufreq_resume; + + pdev = platform_device_register_data(NULL, "cpufreq-dt", -1, &pdata, + sizeof(pdata)); + ret = PTR_ERR_OR_ZERO(pdev); + if (ret) + goto disable_dvfs; + + armada37xx_cpufreq_state->cpu_dev = cpu_dev; + armada37xx_cpufreq_state->pdev = pdev; + platform_set_drvdata(pdev, dvfs); + return 0; + +disable_dvfs: + armada37xx_cpufreq_disable_dvfs(nb_pm_base); +remove_opp: + /* clean-up the already added opp before leaving */ + while (load_lvl-- > ARMADA_37XX_DVFS_LOAD_0) { + freq = base_frequency / dvfs->divider[load_lvl]; + dev_pm_opp_remove(cpu_dev, freq); + } + + kfree(armada37xx_cpufreq_state); + + return ret; +} +/* late_initcall, to guarantee the driver is loaded after A37xx clock driver */ +late_initcall(armada37xx_cpufreq_driver_init); + +static void __exit armada37xx_cpufreq_driver_exit(void) +{ + struct platform_device *pdev = armada37xx_cpufreq_state->pdev; + struct armada_37xx_dvfs *dvfs = platform_get_drvdata(pdev); + unsigned long freq; + int load_lvl; + + platform_device_unregister(pdev); + + armada37xx_cpufreq_disable_dvfs(armada37xx_cpufreq_state->regmap); + + for (load_lvl = ARMADA_37XX_DVFS_LOAD_0; load_lvl < LOAD_LEVEL_NR; load_lvl++) { + freq = dvfs->cpu_freq_max / dvfs->divider[load_lvl]; + dev_pm_opp_remove(armada37xx_cpufreq_state->cpu_dev, freq); + } + + kfree(armada37xx_cpufreq_state); +} +module_exit(armada37xx_cpufreq_driver_exit); + +static const struct of_device_id __maybe_unused armada37xx_cpufreq_of_match[] = { + { .compatible = "marvell,armada-3700-nb-pm" }, + { }, +}; +MODULE_DEVICE_TABLE(of, armada37xx_cpufreq_of_match); + +MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>"); +MODULE_DESCRIPTION("Armada 37xx cpufreq driver"); +MODULE_LICENSE("GPL"); |