linux/drivers/cpufreq/armada-37xx-cpufreq.c
Miquel Raynal 9c28d6df75 cpufreq: add suspend/resume support in Armada 37xx DVFS driver
Add suspend/resume hooks in Armada 37xx DVFS driver to handle S2RAM
operations. As there is currently no 'driver' structure, create one
to store both the regmap and the register values during suspend
operation.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-05-10 11:43:59 +02:00

318 lines
8.6 KiB
C

// 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"
/* 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 armada37xx_cpufreq_state {
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];
};
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 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 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");
clk_put(clk);
return -EINVAL;
}
dvfs = armada_37xx_cpu_freq_info_get(cur_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_dvfs_setup(nb_pm_base, clk, dvfs->divider);
clk_put(clk);
for (load_lvl = ARMADA_37XX_DVFS_LOAD_0; load_lvl < LOAD_LEVEL_NR;
load_lvl++) {
freq = cur_frequency / dvfs->divider[load_lvl];
ret = dev_pm_opp_add(cpu_dev, freq, 0);
if (ret)
goto remove_opp;
}
/* Now that everything is setup, enable the DVFS at hardware level */
armada37xx_cpufreq_enable_dvfs(nb_pm_base);
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;
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 = cur_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);
MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
MODULE_DESCRIPTION("Armada 37xx cpufreq driver");
MODULE_LICENSE("GPL");