![Gregory CLEMENT](/assets/img/avatar_default.png)
The frequency calculation was based on the current(max) frequency of the
CPU. However for low frequency, the value used was already the parent
frequency divided by a factor of 2.
Instead of using this frequency, this fix directly get the frequency from
the parent clock.
Fixes: 92ce45fb87
("cpufreq: Add DVFS support for Armada 37xx")
Cc: <stable@vger.kernel.org>
Reported-by: Christian Neubert <christian.neubert.86@gmail.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
491 lines
14 KiB
C
491 lines
14 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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#include "cpufreq-dt.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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/* AVS register set */
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#define ARMADA_37XX_AVS_CTL0 0x0
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#define ARMADA_37XX_AVS_ENABLE BIT(30)
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#define ARMADA_37XX_AVS_HIGH_VDD_LIMIT 16
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#define ARMADA_37XX_AVS_LOW_VDD_LIMIT 22
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#define ARMADA_37XX_AVS_VDD_MASK 0x3F
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#define ARMADA_37XX_AVS_CTL2 0x8
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#define ARMADA_37XX_AVS_LOW_VDD_EN BIT(6)
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#define ARMADA_37XX_AVS_VSET(x) (0x1C + 4 * (x))
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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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#define MIN_VOLT_MV 1000
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/* AVS value for the corresponding voltage (in mV) */
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static int avs_map[] = {
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747, 758, 770, 782, 793, 805, 817, 828, 840, 852, 863, 875, 887, 898,
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910, 922, 933, 945, 957, 968, 980, 992, 1003, 1015, 1027, 1038, 1050,
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1062, 1073, 1085, 1097, 1108, 1120, 1132, 1143, 1155, 1167, 1178, 1190,
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1202, 1213, 1225, 1237, 1248, 1260, 1272, 1283, 1295, 1307, 1318, 1330,
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1342
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};
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struct armada37xx_cpufreq_state {
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struct regmap *regmap;
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u32 nb_l0l1;
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u32 nb_l2l3;
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u32 nb_dyn_mod;
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u32 nb_cpu_load;
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};
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static struct armada37xx_cpufreq_state *armada37xx_cpufreq_state;
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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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u32 avs[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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/*
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* Find out the armada 37x supported AVS value whose voltage value is
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* the round-up closest to the target voltage value.
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*/
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static u32 armada_37xx_avs_val_match(int target_vm)
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{
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u32 avs;
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/* Find out the round-up closest supported voltage value */
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for (avs = 0; avs < ARRAY_SIZE(avs_map); avs++)
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if (avs_map[avs] >= target_vm)
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break;
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/*
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* If all supported voltages are smaller than target one,
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* choose the largest supported voltage
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*/
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if (avs == ARRAY_SIZE(avs_map))
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avs = ARRAY_SIZE(avs_map) - 1;
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return avs;
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}
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/*
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* For Armada 37xx soc, L0(VSET0) VDD AVS value is set to SVC revision
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* value or a default value when SVC is not supported.
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* - L0 can be read out from the register of AVS_CTRL_0 and L0 voltage
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* can be got from the mapping table of avs_map.
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* - L1 voltage should be about 100mv smaller than L0 voltage
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* - L2 & L3 voltage should be about 150mv smaller than L0 voltage.
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* This function calculates L1 & L2 & L3 AVS values dynamically based
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* on L0 voltage and fill all AVS values to the AVS value table.
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*/
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static void __init armada37xx_cpufreq_avs_configure(struct regmap *base,
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struct armada_37xx_dvfs *dvfs)
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{
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unsigned int target_vm;
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int load_level = 0;
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u32 l0_vdd_min;
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if (base == NULL)
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return;
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/* Get L0 VDD min value */
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regmap_read(base, ARMADA_37XX_AVS_CTL0, &l0_vdd_min);
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l0_vdd_min = (l0_vdd_min >> ARMADA_37XX_AVS_LOW_VDD_LIMIT) &
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ARMADA_37XX_AVS_VDD_MASK;
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if (l0_vdd_min >= ARRAY_SIZE(avs_map)) {
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pr_err("L0 VDD MIN %d is not correct.\n", l0_vdd_min);
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return;
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}
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dvfs->avs[0] = l0_vdd_min;
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if (avs_map[l0_vdd_min] <= MIN_VOLT_MV) {
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/*
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* If L0 voltage is smaller than 1000mv, then all VDD sets
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* use L0 voltage;
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*/
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u32 avs_min = armada_37xx_avs_val_match(MIN_VOLT_MV);
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for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++)
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dvfs->avs[load_level] = avs_min;
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return;
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}
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/*
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* L1 voltage is equal to L0 voltage - 100mv and it must be
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* larger than 1000mv
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*/
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target_vm = avs_map[l0_vdd_min] - 100;
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target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV;
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dvfs->avs[1] = armada_37xx_avs_val_match(target_vm);
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/*
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* L2 & L3 voltage is equal to L0 voltage - 150mv and it must
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* be larger than 1000mv
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*/
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target_vm = avs_map[l0_vdd_min] - 150;
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target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV;
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dvfs->avs[2] = dvfs->avs[3] = armada_37xx_avs_val_match(target_vm);
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}
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static void __init armada37xx_cpufreq_avs_setup(struct regmap *base,
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struct armada_37xx_dvfs *dvfs)
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{
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unsigned int avs_val = 0, freq;
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int load_level = 0;
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if (base == NULL)
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return;
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/* Disable AVS before the configuration */
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regmap_update_bits(base, ARMADA_37XX_AVS_CTL0,
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ARMADA_37XX_AVS_ENABLE, 0);
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/* Enable low voltage mode */
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regmap_update_bits(base, ARMADA_37XX_AVS_CTL2,
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ARMADA_37XX_AVS_LOW_VDD_EN,
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ARMADA_37XX_AVS_LOW_VDD_EN);
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for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++) {
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freq = dvfs->cpu_freq_max / dvfs->divider[load_level];
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avs_val = dvfs->avs[load_level];
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regmap_update_bits(base, ARMADA_37XX_AVS_VSET(load_level-1),
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ARMADA_37XX_AVS_VDD_MASK << ARMADA_37XX_AVS_HIGH_VDD_LIMIT |
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ARMADA_37XX_AVS_VDD_MASK << ARMADA_37XX_AVS_LOW_VDD_LIMIT,
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avs_val << ARMADA_37XX_AVS_HIGH_VDD_LIMIT |
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avs_val << ARMADA_37XX_AVS_LOW_VDD_LIMIT);
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}
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/* Enable AVS after the configuration */
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regmap_update_bits(base, ARMADA_37XX_AVS_CTL0,
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ARMADA_37XX_AVS_ENABLE,
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ARMADA_37XX_AVS_ENABLE);
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}
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static void 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 armada37xx_cpufreq_suspend(struct cpufreq_policy *policy)
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{
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struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state;
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regmap_read(state->regmap, ARMADA_37XX_NB_L0L1, &state->nb_l0l1);
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regmap_read(state->regmap, ARMADA_37XX_NB_L2L3, &state->nb_l2l3);
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regmap_read(state->regmap, ARMADA_37XX_NB_CPU_LOAD,
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&state->nb_cpu_load);
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regmap_read(state->regmap, ARMADA_37XX_NB_DYN_MOD, &state->nb_dyn_mod);
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return 0;
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}
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static int armada37xx_cpufreq_resume(struct cpufreq_policy *policy)
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{
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struct armada37xx_cpufreq_state *state = armada37xx_cpufreq_state;
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/* Ensure DVFS is disabled otherwise the following registers are RO */
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armada37xx_cpufreq_disable_dvfs(state->regmap);
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regmap_write(state->regmap, ARMADA_37XX_NB_L0L1, state->nb_l0l1);
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regmap_write(state->regmap, ARMADA_37XX_NB_L2L3, state->nb_l2l3);
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regmap_write(state->regmap, ARMADA_37XX_NB_CPU_LOAD,
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state->nb_cpu_load);
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/*
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* NB_DYN_MOD register is the one that actually enable back DVFS if it
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* was enabled before the suspend operation. This must be done last
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* otherwise other registers are not writable.
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*/
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regmap_write(state->regmap, ARMADA_37XX_NB_DYN_MOD, state->nb_dyn_mod);
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return 0;
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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 cpufreq_dt_platform_data pdata;
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struct armada_37xx_dvfs *dvfs;
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struct platform_device *pdev;
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unsigned long freq;
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unsigned int cur_frequency, base_frequency;
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struct regmap *nb_pm_base, *avs_base;
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struct device *cpu_dev;
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int load_lvl, ret;
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struct clk *clk, *parent;
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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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avs_base =
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syscon_regmap_lookup_by_compatible("marvell,armada-3700-avs");
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/* if AVS is not present don't use it but still try to setup dvfs */
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if (IS_ERR(avs_base)) {
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pr_info("Syscon failed for Adapting Voltage Scaling: skip it\n");
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avs_base = NULL;
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}
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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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parent = clk_get_parent(clk);
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if (IS_ERR(parent)) {
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dev_err(cpu_dev, "Cannot get parent clock for CPU0\n");
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clk_put(clk);
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return PTR_ERR(parent);
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}
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/* Get parent CPU frequency */
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base_frequency = clk_get_rate(parent);
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if (!base_frequency) {
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dev_err(cpu_dev, "Failed to get parent 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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/* 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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clk_put(clk);
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return -EINVAL;
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}
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armada37xx_cpufreq_state = kmalloc(sizeof(*armada37xx_cpufreq_state),
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GFP_KERNEL);
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if (!armada37xx_cpufreq_state) {
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clk_put(clk);
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return -ENOMEM;
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}
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armada37xx_cpufreq_state->regmap = nb_pm_base;
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armada37xx_cpufreq_avs_configure(avs_base, dvfs);
|
|
armada37xx_cpufreq_avs_setup(avs_base, dvfs);
|
|
|
|
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++) {
|
|
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);
|
|
|
|
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");
|