244 lines
6.7 KiB
C
244 lines
6.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* CPU frequency scaling support for Armada 37xx platform.
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*
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* Copyright (C) 2017 Marvell
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*
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* Gregory CLEMENT <gregory.clement@free-electrons.com>
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*/
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#include <linux/clk.h>
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#include <linux/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/err.h>
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/mfd/syscon.h>
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#include <linux/module.h>
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#include <linux/of_address.h>
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#include <linux/of_device.h>
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#include <linux/of_irq.h>
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#include <linux/platform_device.h>
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#include <linux/pm_opp.h>
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#include <linux/regmap.h>
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#include <linux/slab.h>
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/* Power management in North Bridge register set */
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#define ARMADA_37XX_NB_L0L1 0x18
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#define ARMADA_37XX_NB_L2L3 0x1C
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#define ARMADA_37XX_NB_TBG_DIV_OFF 13
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#define ARMADA_37XX_NB_TBG_DIV_MASK 0x7
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#define ARMADA_37XX_NB_CLK_SEL_OFF 11
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#define ARMADA_37XX_NB_CLK_SEL_MASK 0x1
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#define ARMADA_37XX_NB_CLK_SEL_TBG 0x1
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#define ARMADA_37XX_NB_TBG_SEL_OFF 9
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#define ARMADA_37XX_NB_TBG_SEL_MASK 0x3
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#define ARMADA_37XX_NB_VDD_SEL_OFF 6
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#define ARMADA_37XX_NB_VDD_SEL_MASK 0x3
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#define ARMADA_37XX_NB_CONFIG_SHIFT 16
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#define ARMADA_37XX_NB_DYN_MOD 0x24
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#define ARMADA_37XX_NB_CLK_SEL_EN BIT(26)
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#define ARMADA_37XX_NB_TBG_EN BIT(28)
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#define ARMADA_37XX_NB_DIV_EN BIT(29)
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#define ARMADA_37XX_NB_VDD_EN BIT(30)
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#define ARMADA_37XX_NB_DFS_EN BIT(31)
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#define ARMADA_37XX_NB_CPU_LOAD 0x30
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#define ARMADA_37XX_NB_CPU_LOAD_MASK 0x3
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#define ARMADA_37XX_DVFS_LOAD_0 0
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#define ARMADA_37XX_DVFS_LOAD_1 1
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#define ARMADA_37XX_DVFS_LOAD_2 2
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#define ARMADA_37XX_DVFS_LOAD_3 3
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/*
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* On Armada 37xx the Power management manages 4 level of CPU load,
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* each level can be associated with a CPU clock source, a CPU
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* divider, a VDD level, etc...
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*/
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#define LOAD_LEVEL_NR 4
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struct armada_37xx_dvfs {
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u32 cpu_freq_max;
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u8 divider[LOAD_LEVEL_NR];
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};
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static struct armada_37xx_dvfs armada_37xx_dvfs[] = {
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{.cpu_freq_max = 1200*1000*1000, .divider = {1, 2, 4, 6} },
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{.cpu_freq_max = 1000*1000*1000, .divider = {1, 2, 4, 5} },
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{.cpu_freq_max = 800*1000*1000, .divider = {1, 2, 3, 4} },
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{.cpu_freq_max = 600*1000*1000, .divider = {2, 4, 5, 6} },
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};
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static struct armada_37xx_dvfs *armada_37xx_cpu_freq_info_get(u32 freq)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(armada_37xx_dvfs); i++) {
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if (freq == armada_37xx_dvfs[i].cpu_freq_max)
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return &armada_37xx_dvfs[i];
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}
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pr_err("Unsupported CPU frequency %d MHz\n", freq/1000000);
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return NULL;
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}
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/*
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* Setup the four level managed by the hardware. Once the four level
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* will be configured then the DVFS will be enabled.
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*/
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static void __init armada37xx_cpufreq_dvfs_setup(struct regmap *base,
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struct clk *clk, u8 *divider)
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{
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int load_lvl;
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struct clk *parent;
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for (load_lvl = 0; load_lvl < LOAD_LEVEL_NR; load_lvl++) {
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unsigned int reg, mask, val, offset = 0;
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if (load_lvl <= ARMADA_37XX_DVFS_LOAD_1)
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reg = ARMADA_37XX_NB_L0L1;
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else
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reg = ARMADA_37XX_NB_L2L3;
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if (load_lvl == ARMADA_37XX_DVFS_LOAD_0 ||
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load_lvl == ARMADA_37XX_DVFS_LOAD_2)
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offset += ARMADA_37XX_NB_CONFIG_SHIFT;
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/* Set cpu clock source, for all the level we use TBG */
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val = ARMADA_37XX_NB_CLK_SEL_TBG << ARMADA_37XX_NB_CLK_SEL_OFF;
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mask = (ARMADA_37XX_NB_CLK_SEL_MASK
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<< ARMADA_37XX_NB_CLK_SEL_OFF);
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/*
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* Set cpu divider based on the pre-computed array in
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* order to have balanced step.
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*/
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val |= divider[load_lvl] << ARMADA_37XX_NB_TBG_DIV_OFF;
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mask |= (ARMADA_37XX_NB_TBG_DIV_MASK
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<< ARMADA_37XX_NB_TBG_DIV_OFF);
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/* Set VDD divider which is actually the load level. */
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val |= load_lvl << ARMADA_37XX_NB_VDD_SEL_OFF;
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mask |= (ARMADA_37XX_NB_VDD_SEL_MASK
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<< ARMADA_37XX_NB_VDD_SEL_OFF);
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val <<= offset;
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mask <<= offset;
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regmap_update_bits(base, reg, mask, val);
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}
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/*
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* Set cpu clock source, for all the level we keep the same
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* clock source that the one already configured. For this one
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* we need to use the clock framework
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*/
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parent = clk_get_parent(clk);
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clk_set_parent(clk, parent);
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}
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static void __init armada37xx_cpufreq_disable_dvfs(struct regmap *base)
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{
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unsigned int reg = ARMADA_37XX_NB_DYN_MOD,
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mask = ARMADA_37XX_NB_DFS_EN;
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regmap_update_bits(base, reg, mask, 0);
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}
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static void __init armada37xx_cpufreq_enable_dvfs(struct regmap *base)
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{
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unsigned int val, reg = ARMADA_37XX_NB_CPU_LOAD,
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mask = ARMADA_37XX_NB_CPU_LOAD_MASK;
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/* Start with the highest load (0) */
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val = ARMADA_37XX_DVFS_LOAD_0;
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regmap_update_bits(base, reg, mask, val);
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/* Now enable DVFS for the CPUs */
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reg = ARMADA_37XX_NB_DYN_MOD;
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mask = ARMADA_37XX_NB_CLK_SEL_EN | ARMADA_37XX_NB_TBG_EN |
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ARMADA_37XX_NB_DIV_EN | ARMADA_37XX_NB_VDD_EN |
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ARMADA_37XX_NB_DFS_EN;
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regmap_update_bits(base, reg, mask, mask);
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}
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static int __init armada37xx_cpufreq_driver_init(void)
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{
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struct armada_37xx_dvfs *dvfs;
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struct platform_device *pdev;
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unsigned int cur_frequency;
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struct regmap *nb_pm_base;
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struct device *cpu_dev;
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int load_lvl, ret;
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struct clk *clk;
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nb_pm_base =
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syscon_regmap_lookup_by_compatible("marvell,armada-3700-nb-pm");
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if (IS_ERR(nb_pm_base))
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return -ENODEV;
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/* Before doing any configuration on the DVFS first, disable it */
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armada37xx_cpufreq_disable_dvfs(nb_pm_base);
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/*
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* On CPU 0 register the operating points supported (which are
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* the nominal CPU frequency and full integer divisions of
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* it).
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*/
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cpu_dev = get_cpu_device(0);
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if (!cpu_dev) {
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dev_err(cpu_dev, "Cannot get CPU\n");
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return -ENODEV;
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}
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clk = clk_get(cpu_dev, 0);
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if (IS_ERR(clk)) {
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dev_err(cpu_dev, "Cannot get clock for CPU0\n");
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return PTR_ERR(clk);
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}
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/* Get nominal (current) CPU frequency */
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cur_frequency = clk_get_rate(clk);
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if (!cur_frequency) {
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dev_err(cpu_dev, "Failed to get clock rate for CPU\n");
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clk_put(clk);
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return -EINVAL;
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}
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dvfs = armada_37xx_cpu_freq_info_get(cur_frequency);
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if (!dvfs)
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return -EINVAL;
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armada37xx_cpufreq_dvfs_setup(nb_pm_base, clk, dvfs->divider);
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clk_put(clk);
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for (load_lvl = ARMADA_37XX_DVFS_LOAD_0; load_lvl < LOAD_LEVEL_NR;
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load_lvl++) {
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unsigned long freq = cur_frequency / dvfs->divider[load_lvl];
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ret = dev_pm_opp_add(cpu_dev, freq, 0);
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if (ret) {
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/* clean-up the already added opp before leaving */
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while (load_lvl-- > ARMADA_37XX_DVFS_LOAD_0) {
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freq = cur_frequency / dvfs->divider[load_lvl];
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dev_pm_opp_remove(cpu_dev, freq);
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}
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return ret;
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}
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}
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/* Now that everything is setup, enable the DVFS at hardware level */
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armada37xx_cpufreq_enable_dvfs(nb_pm_base);
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pdev = platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
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return PTR_ERR_OR_ZERO(pdev);
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}
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/* late_initcall, to guarantee the driver is loaded after A37xx clock driver */
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late_initcall(armada37xx_cpufreq_driver_init);
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MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
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MODULE_DESCRIPTION("Armada 37xx cpufreq driver");
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MODULE_LICENSE("GPL");
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