// 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>
#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");
