diff options
Diffstat (limited to 'drivers/memory/samsung/exynos5422-dmc.c')
| -rw-r--r-- | drivers/memory/samsung/exynos5422-dmc.c | 1593 |
1 files changed, 1593 insertions, 0 deletions
diff --git a/drivers/memory/samsung/exynos5422-dmc.c b/drivers/memory/samsung/exynos5422-dmc.c new file mode 100644 index 000000000..c491cd549 --- /dev/null +++ b/drivers/memory/samsung/exynos5422-dmc.c @@ -0,0 +1,1593 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2019 Samsung Electronics Co., Ltd. + * Author: Lukasz Luba <l.luba@partner.samsung.com> + */ + +#include <linux/clk.h> +#include <linux/devfreq.h> +#include <linux/devfreq-event.h> +#include <linux/device.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/of_device.h> +#include <linux/pm_opp.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/regulator/consumer.h> +#include <linux/slab.h> +#include "../jedec_ddr.h" +#include "../of_memory.h" + +static int irqmode; +module_param(irqmode, int, 0644); +MODULE_PARM_DESC(irqmode, "Enable IRQ mode (0=off [default], 1=on)"); + +#define EXYNOS5_DREXI_TIMINGAREF (0x0030) +#define EXYNOS5_DREXI_TIMINGROW0 (0x0034) +#define EXYNOS5_DREXI_TIMINGDATA0 (0x0038) +#define EXYNOS5_DREXI_TIMINGPOWER0 (0x003C) +#define EXYNOS5_DREXI_TIMINGROW1 (0x00E4) +#define EXYNOS5_DREXI_TIMINGDATA1 (0x00E8) +#define EXYNOS5_DREXI_TIMINGPOWER1 (0x00EC) +#define CDREX_PAUSE (0x2091c) +#define CDREX_LPDDR3PHY_CON3 (0x20a20) +#define CDREX_LPDDR3PHY_CLKM_SRC (0x20700) +#define EXYNOS5_TIMING_SET_SWI BIT(28) +#define USE_MX_MSPLL_TIMINGS (1) +#define USE_BPLL_TIMINGS (0) +#define EXYNOS5_AREF_NORMAL (0x2e) + +#define DREX_PPCCLKCON (0x0130) +#define DREX_PEREV2CONFIG (0x013c) +#define DREX_PMNC_PPC (0xE000) +#define DREX_CNTENS_PPC (0xE010) +#define DREX_CNTENC_PPC (0xE020) +#define DREX_INTENS_PPC (0xE030) +#define DREX_INTENC_PPC (0xE040) +#define DREX_FLAG_PPC (0xE050) +#define DREX_PMCNT2_PPC (0xE130) + +/* + * A value for register DREX_PMNC_PPC which should be written to reset + * the cycle counter CCNT (a reference wall clock). It sets zero to the + * CCNT counter. + */ +#define CC_RESET BIT(2) + +/* + * A value for register DREX_PMNC_PPC which does the reset of all performance + * counters to zero. + */ +#define PPC_COUNTER_RESET BIT(1) + +/* + * Enables all configured counters (including cycle counter). The value should + * be written to the register DREX_PMNC_PPC. + */ +#define PPC_ENABLE BIT(0) + +/* A value for register DREX_PPCCLKCON which enables performance events clock. + * Must be written before first access to the performance counters register + * set, otherwise it could crash. + */ +#define PEREV_CLK_EN BIT(0) + +/* + * Values which are used to enable counters, interrupts or configure flags of + * the performance counters. They configure counter 2 and cycle counter. + */ +#define PERF_CNT2 BIT(2) +#define PERF_CCNT BIT(31) + +/* + * Performance event types which are used for setting the preferred event + * to track in the counters. + * There is a set of different types, the values are from range 0 to 0x6f. + * These settings should be written to the configuration register which manages + * the type of the event (register DREX_PEREV2CONFIG). + */ +#define READ_TRANSFER_CH0 (0x6d) +#define READ_TRANSFER_CH1 (0x6f) + +#define PERF_COUNTER_START_VALUE 0xff000000 +#define PERF_EVENT_UP_DOWN_THRESHOLD 900000000ULL + +/** + * struct dmc_opp_table - Operating level desciption + * @freq_hz: target frequency in Hz + * @volt_uv: target voltage in uV + * + * Covers frequency and voltage settings of the DMC operating mode. + */ +struct dmc_opp_table { + u32 freq_hz; + u32 volt_uv; +}; + +/** + * struct exynos5_dmc - main structure describing DMC device + * @dev: DMC device + * @df: devfreq device structure returned by devfreq framework + * @gov_data: configuration of devfreq governor + * @base_drexi0: DREX0 registers mapping + * @base_drexi1: DREX1 registers mapping + * @clk_regmap: regmap for clock controller registers + * @lock: protects curr_rate and frequency/voltage setting section + * @curr_rate: current frequency + * @curr_volt: current voltage + * @opp: OPP table + * @opp_count: number of 'opp' elements + * @timings_arr_size: number of 'timings' elements + * @timing_row: values for timing row register, for each OPP + * @timing_data: values for timing data register, for each OPP + * @timing_power: balues for timing power register, for each OPP + * @timings: DDR memory timings, from device tree + * @min_tck: DDR memory minimum timing values, from device tree + * @bypass_timing_row: value for timing row register for bypass timings + * @bypass_timing_data: value for timing data register for bypass timings + * @bypass_timing_power: value for timing power register for bypass + * timings + * @vdd_mif: Memory interface regulator + * @fout_spll: clock: SPLL + * @fout_bpll: clock: BPLL + * @mout_spll: clock: mux SPLL + * @mout_bpll: clock: mux BPLL + * @mout_mclk_cdrex: clock: mux mclk_cdrex + * @mout_mx_mspll_ccore: clock: mux mx_mspll_ccore + * @counter: devfreq events + * @num_counters: number of 'counter' elements + * @last_overflow_ts: time (in ns) of last overflow of each DREX + * @load: utilization in percents + * @total: total time between devfreq events + * @in_irq_mode: whether running in interrupt mode (true) + * or polling (false) + * + * The main structure for the Dynamic Memory Controller which covers clocks, + * memory regions, HW information, parameters and current operating mode. + */ +struct exynos5_dmc { + struct device *dev; + struct devfreq *df; + struct devfreq_simple_ondemand_data gov_data; + void __iomem *base_drexi0; + void __iomem *base_drexi1; + struct regmap *clk_regmap; + /* Protects curr_rate and frequency/voltage setting section */ + struct mutex lock; + unsigned long curr_rate; + unsigned long curr_volt; + struct dmc_opp_table *opp; + int opp_count; + u32 timings_arr_size; + u32 *timing_row; + u32 *timing_data; + u32 *timing_power; + const struct lpddr3_timings *timings; + const struct lpddr3_min_tck *min_tck; + u32 bypass_timing_row; + u32 bypass_timing_data; + u32 bypass_timing_power; + struct regulator *vdd_mif; + struct clk *fout_spll; + struct clk *fout_bpll; + struct clk *mout_spll; + struct clk *mout_bpll; + struct clk *mout_mclk_cdrex; + struct clk *mout_mx_mspll_ccore; + struct devfreq_event_dev **counter; + int num_counters; + u64 last_overflow_ts[2]; + unsigned long load; + unsigned long total; + bool in_irq_mode; +}; + +#define TIMING_FIELD(t_name, t_bit_beg, t_bit_end) \ + { .name = t_name, .bit_beg = t_bit_beg, .bit_end = t_bit_end } + +#define TIMING_VAL2REG(timing, t_val) \ +({ \ + u32 __val; \ + __val = (t_val) << (timing)->bit_beg; \ + __val; \ +}) + +struct timing_reg { + char *name; + int bit_beg; + int bit_end; + unsigned int val; +}; + +static const struct timing_reg timing_row_reg_fields[] = { + TIMING_FIELD("tRFC", 24, 31), + TIMING_FIELD("tRRD", 20, 23), + TIMING_FIELD("tRP", 16, 19), + TIMING_FIELD("tRCD", 12, 15), + TIMING_FIELD("tRC", 6, 11), + TIMING_FIELD("tRAS", 0, 5), +}; + +static const struct timing_reg timing_data_reg_fields[] = { + TIMING_FIELD("tWTR", 28, 31), + TIMING_FIELD("tWR", 24, 27), + TIMING_FIELD("tRTP", 20, 23), + TIMING_FIELD("tW2W-C2C", 14, 14), + TIMING_FIELD("tR2R-C2C", 12, 12), + TIMING_FIELD("WL", 8, 11), + TIMING_FIELD("tDQSCK", 4, 7), + TIMING_FIELD("RL", 0, 3), +}; + +static const struct timing_reg timing_power_reg_fields[] = { + TIMING_FIELD("tFAW", 26, 31), + TIMING_FIELD("tXSR", 16, 25), + TIMING_FIELD("tXP", 8, 15), + TIMING_FIELD("tCKE", 4, 7), + TIMING_FIELD("tMRD", 0, 3), +}; + +#define TIMING_COUNT (ARRAY_SIZE(timing_row_reg_fields) + \ + ARRAY_SIZE(timing_data_reg_fields) + \ + ARRAY_SIZE(timing_power_reg_fields)) + +static int exynos5_counters_set_event(struct exynos5_dmc *dmc) +{ + int i, ret; + + for (i = 0; i < dmc->num_counters; i++) { + if (!dmc->counter[i]) + continue; + ret = devfreq_event_set_event(dmc->counter[i]); + if (ret < 0) + return ret; + } + return 0; +} + +static int exynos5_counters_enable_edev(struct exynos5_dmc *dmc) +{ + int i, ret; + + for (i = 0; i < dmc->num_counters; i++) { + if (!dmc->counter[i]) + continue; + ret = devfreq_event_enable_edev(dmc->counter[i]); + if (ret < 0) + return ret; + } + return 0; +} + +static int exynos5_counters_disable_edev(struct exynos5_dmc *dmc) +{ + int i, ret; + + for (i = 0; i < dmc->num_counters; i++) { + if (!dmc->counter[i]) + continue; + ret = devfreq_event_disable_edev(dmc->counter[i]); + if (ret < 0) + return ret; + } + return 0; +} + +/** + * find_target_freq_idx() - Finds requested frequency in local DMC configuration + * @dmc: device for which the information is checked + * @target_rate: requested frequency in KHz + * + * Seeks in the local DMC driver structure for the requested frequency value + * and returns index or error value. + */ +static int find_target_freq_idx(struct exynos5_dmc *dmc, + unsigned long target_rate) +{ + int i; + + for (i = dmc->opp_count - 1; i >= 0; i--) + if (dmc->opp[i].freq_hz <= target_rate) + return i; + + return -EINVAL; +} + +/** + * exynos5_switch_timing_regs() - Changes bank register set for DRAM timings + * @dmc: device for which the new settings is going to be applied + * @set: boolean variable passing set value + * + * Changes the register set, which holds timing parameters. + * There is two register sets: 0 and 1. The register set 0 + * is used in normal operation when the clock is provided from main PLL. + * The bank register set 1 is used when the main PLL frequency is going to be + * changed and the clock is taken from alternative, stable source. + * This function switches between these banks according to the + * currently used clock source. + */ +static int exynos5_switch_timing_regs(struct exynos5_dmc *dmc, bool set) +{ + unsigned int reg; + int ret; + + ret = regmap_read(dmc->clk_regmap, CDREX_LPDDR3PHY_CON3, ®); + if (ret) + return ret; + + if (set) + reg |= EXYNOS5_TIMING_SET_SWI; + else + reg &= ~EXYNOS5_TIMING_SET_SWI; + + regmap_write(dmc->clk_regmap, CDREX_LPDDR3PHY_CON3, reg); + + return 0; +} + +/** + * exynos5_init_freq_table() - Initialized PM OPP framework + * @dmc: DMC device for which the frequencies are used for OPP init + * @profile: devfreq device's profile + * + * Populate the devfreq device's OPP table based on current frequency, voltage. + */ +static int exynos5_init_freq_table(struct exynos5_dmc *dmc, + struct devfreq_dev_profile *profile) +{ + int i, ret; + int idx; + unsigned long freq; + + ret = devm_pm_opp_of_add_table(dmc->dev); + if (ret < 0) { + dev_err(dmc->dev, "Failed to get OPP table\n"); + return ret; + } + + dmc->opp_count = dev_pm_opp_get_opp_count(dmc->dev); + + dmc->opp = devm_kmalloc_array(dmc->dev, dmc->opp_count, + sizeof(struct dmc_opp_table), GFP_KERNEL); + if (!dmc->opp) + return -ENOMEM; + + idx = dmc->opp_count - 1; + for (i = 0, freq = ULONG_MAX; i < dmc->opp_count; i++, freq--) { + struct dev_pm_opp *opp; + + opp = dev_pm_opp_find_freq_floor(dmc->dev, &freq); + if (IS_ERR(opp)) + return PTR_ERR(opp); + + dmc->opp[idx - i].freq_hz = freq; + dmc->opp[idx - i].volt_uv = dev_pm_opp_get_voltage(opp); + + dev_pm_opp_put(opp); + } + + return 0; +} + +/** + * exynos5_set_bypass_dram_timings() - Low-level changes of the DRAM timings + * @dmc: device for which the new settings is going to be applied + * + * Low-level function for changing timings for DRAM memory clocking from + * 'bypass' clock source (fixed frequency @400MHz). + * It uses timing bank registers set 1. + */ +static void exynos5_set_bypass_dram_timings(struct exynos5_dmc *dmc) +{ + writel(EXYNOS5_AREF_NORMAL, + dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGAREF); + + writel(dmc->bypass_timing_row, + dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGROW1); + writel(dmc->bypass_timing_row, + dmc->base_drexi1 + EXYNOS5_DREXI_TIMINGROW1); + writel(dmc->bypass_timing_data, + dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGDATA1); + writel(dmc->bypass_timing_data, + dmc->base_drexi1 + EXYNOS5_DREXI_TIMINGDATA1); + writel(dmc->bypass_timing_power, + dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGPOWER1); + writel(dmc->bypass_timing_power, + dmc->base_drexi1 + EXYNOS5_DREXI_TIMINGPOWER1); +} + +/** + * exynos5_dram_change_timings() - Low-level changes of the DRAM final timings + * @dmc: device for which the new settings is going to be applied + * @target_rate: target frequency of the DMC + * + * Low-level function for changing timings for DRAM memory operating from main + * clock source (BPLL), which can have different frequencies. Thus, each + * frequency must have corresponding timings register values in order to keep + * the needed delays. + * It uses timing bank registers set 0. + */ +static int exynos5_dram_change_timings(struct exynos5_dmc *dmc, + unsigned long target_rate) +{ + int idx; + + for (idx = dmc->opp_count - 1; idx >= 0; idx--) + if (dmc->opp[idx].freq_hz <= target_rate) + break; + + if (idx < 0) + return -EINVAL; + + writel(EXYNOS5_AREF_NORMAL, + dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGAREF); + + writel(dmc->timing_row[idx], + dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGROW0); + writel(dmc->timing_row[idx], + dmc->base_drexi1 + EXYNOS5_DREXI_TIMINGROW0); + writel(dmc->timing_data[idx], + dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGDATA0); + writel(dmc->timing_data[idx], + dmc->base_drexi1 + EXYNOS5_DREXI_TIMINGDATA0); + writel(dmc->timing_power[idx], + dmc->base_drexi0 + EXYNOS5_DREXI_TIMINGPOWER0); + writel(dmc->timing_power[idx], + dmc->base_drexi1 + EXYNOS5_DREXI_TIMINGPOWER0); + + return 0; +} + +/** + * exynos5_dmc_align_target_voltage() - Sets the final voltage for the DMC + * @dmc: device for which it is going to be set + * @target_volt: new voltage which is chosen to be final + * + * Function tries to align voltage to the safe level for 'normal' mode. + * It checks the need of higher voltage and changes the value. The target + * voltage might be lower that currently set and still the system will be + * stable. + */ +static int exynos5_dmc_align_target_voltage(struct exynos5_dmc *dmc, + unsigned long target_volt) +{ + int ret = 0; + + if (dmc->curr_volt <= target_volt) + return 0; + + ret = regulator_set_voltage(dmc->vdd_mif, target_volt, + target_volt); + if (!ret) + dmc->curr_volt = target_volt; + + return ret; +} + +/** + * exynos5_dmc_align_bypass_voltage() - Sets the voltage for the DMC + * @dmc: device for which it is going to be set + * @target_volt: new voltage which is chosen to be final + * + * Function tries to align voltage to the safe level for the 'bypass' mode. + * It checks the need of higher voltage and changes the value. + * The target voltage must not be less than currently needed, because + * for current frequency the device might become unstable. + */ +static int exynos5_dmc_align_bypass_voltage(struct exynos5_dmc *dmc, + unsigned long target_volt) +{ + int ret = 0; + + if (dmc->curr_volt >= target_volt) + return 0; + + ret = regulator_set_voltage(dmc->vdd_mif, target_volt, + target_volt); + if (!ret) + dmc->curr_volt = target_volt; + + return ret; +} + +/** + * exynos5_dmc_align_bypass_dram_timings() - Chooses and sets DRAM timings + * @dmc: device for which it is going to be set + * @target_rate: new frequency which is chosen to be final + * + * Function changes the DRAM timings for the temporary 'bypass' mode. + */ +static int exynos5_dmc_align_bypass_dram_timings(struct exynos5_dmc *dmc, + unsigned long target_rate) +{ + int idx = find_target_freq_idx(dmc, target_rate); + + if (idx < 0) + return -EINVAL; + + exynos5_set_bypass_dram_timings(dmc); + + return 0; +} + +/** + * exynos5_dmc_switch_to_bypass_configuration() - Switching to temporary clock + * @dmc: DMC device for which the switching is going to happen + * @target_rate: new frequency which is going to be set as a final + * @target_volt: new voltage which is going to be set as a final + * + * Function configures DMC and clocks for operating in temporary 'bypass' mode. + * This mode is used only temporary but if required, changes voltage and timings + * for DRAM chips. It switches the main clock to stable clock source for the + * period of the main PLL reconfiguration. + */ +static int +exynos5_dmc_switch_to_bypass_configuration(struct exynos5_dmc *dmc, + unsigned long target_rate, + unsigned long target_volt) +{ + int ret; + + /* + * Having higher voltage for a particular frequency does not harm + * the chip. Use it for the temporary frequency change when one + * voltage manipulation might be avoided. + */ + ret = exynos5_dmc_align_bypass_voltage(dmc, target_volt); + if (ret) + return ret; + + /* + * Longer delays for DRAM does not cause crash, the opposite does. + */ + ret = exynos5_dmc_align_bypass_dram_timings(dmc, target_rate); + if (ret) + return ret; + + /* + * Delays are long enough, so use them for the new coming clock. + */ + ret = exynos5_switch_timing_regs(dmc, USE_MX_MSPLL_TIMINGS); + + return ret; +} + +/** + * exynos5_dmc_change_freq_and_volt() - Changes voltage and frequency of the DMC + * using safe procedure + * @dmc: device for which the frequency is going to be changed + * @target_rate: requested new frequency + * @target_volt: requested voltage which corresponds to the new frequency + * + * The DMC frequency change procedure requires a few steps. + * The main requirement is to change the clock source in the clk mux + * for the time of main clock PLL locking. The assumption is that the + * alternative clock source set as parent is stable. + * The second parent's clock frequency is fixed to 400MHz, it is named 'bypass' + * clock. This requires alignment in DRAM timing parameters for the new + * T-period. There is two bank sets for keeping DRAM + * timings: set 0 and set 1. The set 0 is used when main clock source is + * chosen. The 2nd set of regs is used for 'bypass' clock. Switching between + * the two bank sets is part of the process. + * The voltage must also be aligned to the minimum required level. There is + * this intermediate step with switching to 'bypass' parent clock source. + * if the old voltage is lower, it requires an increase of the voltage level. + * The complexity of the voltage manipulation is hidden in low level function. + * In this function there is last alignment of the voltage level at the end. + */ +static int +exynos5_dmc_change_freq_and_volt(struct exynos5_dmc *dmc, + unsigned long target_rate, + unsigned long target_volt) +{ + int ret; + + ret = exynos5_dmc_switch_to_bypass_configuration(dmc, target_rate, + target_volt); + if (ret) + return ret; + + /* + * Voltage is set at least to a level needed for this frequency, + * so switching clock source is safe now. + */ + clk_prepare_enable(dmc->fout_spll); + clk_prepare_enable(dmc->mout_spll); + clk_prepare_enable(dmc->mout_mx_mspll_ccore); + + ret = clk_set_parent(dmc->mout_mclk_cdrex, dmc->mout_mx_mspll_ccore); + if (ret) + goto disable_clocks; + + /* + * We are safe to increase the timings for current bypass frequency. + * Thanks to this the settings will be ready for the upcoming clock + * source change. + */ + exynos5_dram_change_timings(dmc, target_rate); + + clk_set_rate(dmc->fout_bpll, target_rate); + + ret = exynos5_switch_timing_regs(dmc, USE_BPLL_TIMINGS); + if (ret) + goto disable_clocks; + + ret = clk_set_parent(dmc->mout_mclk_cdrex, dmc->mout_bpll); + if (ret) + goto disable_clocks; + + /* + * Make sure if the voltage is not from 'bypass' settings and align to + * the right level for power efficiency. + */ + ret = exynos5_dmc_align_target_voltage(dmc, target_volt); + +disable_clocks: + clk_disable_unprepare(dmc->mout_mx_mspll_ccore); + clk_disable_unprepare(dmc->mout_spll); + clk_disable_unprepare(dmc->fout_spll); + + return ret; +} + +/** + * exynos5_dmc_get_volt_freq() - Gets the frequency and voltage from the OPP + * table. + * @dmc: device for which the frequency is going to be changed + * @freq: requested frequency in KHz + * @target_rate: returned frequency which is the same or lower than + * requested + * @target_volt: returned voltage which corresponds to the returned + * frequency + * @flags: devfreq flags provided for this frequency change request + * + * Function gets requested frequency and checks OPP framework for needed + * frequency and voltage. It populates the values 'target_rate' and + * 'target_volt' or returns error value when OPP framework fails. + */ +static int exynos5_dmc_get_volt_freq(struct exynos5_dmc *dmc, + unsigned long *freq, + unsigned long *target_rate, + unsigned long *target_volt, u32 flags) +{ + struct dev_pm_opp *opp; + + opp = devfreq_recommended_opp(dmc->dev, freq, flags); + if (IS_ERR(opp)) + return PTR_ERR(opp); + + *target_rate = dev_pm_opp_get_freq(opp); + *target_volt = dev_pm_opp_get_voltage(opp); + dev_pm_opp_put(opp); + + return 0; +} + +/** + * exynos5_dmc_target() - Function responsible for changing frequency of DMC + * @dev: device for which the frequency is going to be changed + * @freq: requested frequency in KHz + * @flags: flags provided for this frequency change request + * + * An entry function provided to the devfreq framework which provides frequency + * change of the DMC. The function gets the possible rate from OPP table based + * on requested frequency. It calls the next function responsible for the + * frequency and voltage change. In case of failure, does not set 'curr_rate' + * and returns error value to the framework. + */ +static int exynos5_dmc_target(struct device *dev, unsigned long *freq, + u32 flags) +{ + struct exynos5_dmc *dmc = dev_get_drvdata(dev); + unsigned long target_rate = 0; + unsigned long target_volt = 0; + int ret; + + ret = exynos5_dmc_get_volt_freq(dmc, freq, &target_rate, &target_volt, + flags); + + if (ret) + return ret; + + if (target_rate == dmc->curr_rate) + return 0; + + mutex_lock(&dmc->lock); + + ret = exynos5_dmc_change_freq_and_volt(dmc, target_rate, target_volt); + + if (ret) { + mutex_unlock(&dmc->lock); + return ret; + } + + dmc->curr_rate = target_rate; + + mutex_unlock(&dmc->lock); + return 0; +} + +/** + * exynos5_counters_get() - Gets the performance counters values. + * @dmc: device for which the counters are going to be checked + * @load_count: variable which is populated with counter value + * @total_count: variable which is used as 'wall clock' reference + * + * Function which provides performance counters values. It sums up counters for + * two DMC channels. The 'total_count' is used as a reference and max value. + * The ratio 'load_count/total_count' shows the busy percentage [0%, 100%]. + */ +static int exynos5_counters_get(struct exynos5_dmc *dmc, + unsigned long *load_count, + unsigned long *total_count) +{ + unsigned long total = 0; + struct devfreq_event_data event; + int ret, i; + + *load_count = 0; + + /* Take into account only read+write counters, but stop all */ + for (i = 0; i < dmc->num_counters; i++) { + if (!dmc->counter[i]) + continue; + + ret = devfreq_event_get_event(dmc->counter[i], &event); + if (ret < 0) + return ret; + + *load_count += event.load_count; + + if (total < event.total_count) + total = event.total_count; + } + + *total_count = total; + + return 0; +} + +/** + * exynos5_dmc_start_perf_events() - Setup and start performance event counters + * @dmc: device for which the counters are going to be checked + * @beg_value: initial value for the counter + * + * Function which enables needed counters, interrupts and sets initial values + * then starts the counters. + */ +static void exynos5_dmc_start_perf_events(struct exynos5_dmc *dmc, + u32 beg_value) +{ + /* Enable interrupts for counter 2 */ + writel(PERF_CNT2, dmc->base_drexi0 + DREX_INTENS_PPC); + writel(PERF_CNT2, dmc->base_drexi1 + DREX_INTENS_PPC); + + /* Enable counter 2 and CCNT */ + writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi0 + DREX_CNTENS_PPC); + writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi1 + DREX_CNTENS_PPC); + + /* Clear overflow flag for all counters */ + writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi0 + DREX_FLAG_PPC); + writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi1 + DREX_FLAG_PPC); + + /* Reset all counters */ + writel(CC_RESET | PPC_COUNTER_RESET, dmc->base_drexi0 + DREX_PMNC_PPC); + writel(CC_RESET | PPC_COUNTER_RESET, dmc->base_drexi1 + DREX_PMNC_PPC); + + /* + * Set start value for the counters, the number of samples that + * will be gathered is calculated as: 0xffffffff - beg_value + */ + writel(beg_value, dmc->base_drexi0 + DREX_PMCNT2_PPC); + writel(beg_value, dmc->base_drexi1 + DREX_PMCNT2_PPC); + + /* Start all counters */ + writel(PPC_ENABLE, dmc->base_drexi0 + DREX_PMNC_PPC); + writel(PPC_ENABLE, dmc->base_drexi1 + DREX_PMNC_PPC); +} + +/** + * exynos5_dmc_perf_events_calc() - Calculate utilization + * @dmc: device for which the counters are going to be checked + * @diff_ts: time between last interrupt and current one + * + * Function which calculates needed utilization for the devfreq governor. + * It prepares values for 'busy_time' and 'total_time' based on elapsed time + * between interrupts, which approximates utilization. + */ +static void exynos5_dmc_perf_events_calc(struct exynos5_dmc *dmc, u64 diff_ts) +{ + /* + * This is a simple algorithm for managing traffic on DMC. + * When there is almost no load the counters overflow every 4s, + * no mater the DMC frequency. + * The high load might be approximated using linear function. + * Knowing that, simple calculation can provide 'busy_time' and + * 'total_time' to the devfreq governor which picks up target + * frequency. + * We want a fast ramp up and slow decay in frequency change function. + */ + if (diff_ts < PERF_EVENT_UP_DOWN_THRESHOLD) { + /* + * Set higher utilization for the simple_ondemand governor. + * The governor should increase the frequency of the DMC. + */ + dmc->load = 70; + dmc->total = 100; + } else { + /* + * Set low utilization for the simple_ondemand governor. + * The governor should decrease the frequency of the DMC. + */ + dmc->load = 35; + dmc->total = 100; + } + + dev_dbg(dmc->dev, "diff_ts=%llu\n", diff_ts); +} + +/** + * exynos5_dmc_perf_events_check() - Checks the status of the counters + * @dmc: device for which the counters are going to be checked + * + * Function which is called from threaded IRQ to check the counters state + * and to call approximation for the needed utilization. + */ +static void exynos5_dmc_perf_events_check(struct exynos5_dmc *dmc) +{ + u32 val; + u64 diff_ts, ts; + + ts = ktime_get_ns(); + + /* Stop all counters */ + writel(0, dmc->base_drexi0 + DREX_PMNC_PPC); + writel(0, dmc->base_drexi1 + DREX_PMNC_PPC); + + /* Check the source in interrupt flag registers (which channel) */ + val = readl(dmc->base_drexi0 + DREX_FLAG_PPC); + if (val) { + diff_ts = ts - dmc->last_overflow_ts[0]; + dmc->last_overflow_ts[0] = ts; + dev_dbg(dmc->dev, "drex0 0xE050 val= 0x%08x\n", val); + } else { + val = readl(dmc->base_drexi1 + DREX_FLAG_PPC); + diff_ts = ts - dmc->last_overflow_ts[1]; + dmc->last_overflow_ts[1] = ts; + dev_dbg(dmc->dev, "drex1 0xE050 val= 0x%08x\n", val); + } + + exynos5_dmc_perf_events_calc(dmc, diff_ts); + + exynos5_dmc_start_perf_events(dmc, PERF_COUNTER_START_VALUE); +} + +/** + * exynos5_dmc_enable_perf_events() - Enable performance events + * @dmc: device for which the counters are going to be checked + * + * Function which is setup needed environment and enables counters. + */ +static void exynos5_dmc_enable_perf_events(struct exynos5_dmc *dmc) +{ + u64 ts; + + /* Enable Performance Event Clock */ + writel(PEREV_CLK_EN, dmc->base_drexi0 + DREX_PPCCLKCON); + writel(PEREV_CLK_EN, dmc->base_drexi1 + DREX_PPCCLKCON); + + /* Select read transfers as performance event2 */ + writel(READ_TRANSFER_CH0, dmc->base_drexi0 + DREX_PEREV2CONFIG); + writel(READ_TRANSFER_CH1, dmc->base_drexi1 + DREX_PEREV2CONFIG); + + ts = ktime_get_ns(); + dmc->last_overflow_ts[0] = ts; + dmc->last_overflow_ts[1] = ts; + + /* Devfreq shouldn't be faster than initialization, play safe though. */ + dmc->load = 99; + dmc->total = 100; +} + +/** + * exynos5_dmc_disable_perf_events() - Disable performance events + * @dmc: device for which the counters are going to be checked + * + * Function which stops, disables performance event counters and interrupts. + */ +static void exynos5_dmc_disable_perf_events(struct exynos5_dmc *dmc) +{ + /* Stop all counters */ + writel(0, dmc->base_drexi0 + DREX_PMNC_PPC); + writel(0, dmc->base_drexi1 + DREX_PMNC_PPC); + + /* Disable interrupts for counter 2 */ + writel(PERF_CNT2, dmc->base_drexi0 + DREX_INTENC_PPC); + writel(PERF_CNT2, dmc->base_drexi1 + DREX_INTENC_PPC); + + /* Disable counter 2 and CCNT */ + writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi0 + DREX_CNTENC_PPC); + writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi1 + DREX_CNTENC_PPC); + + /* Clear overflow flag for all counters */ + writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi0 + DREX_FLAG_PPC); + writel(PERF_CNT2 | PERF_CCNT, dmc->base_drexi1 + DREX_FLAG_PPC); +} + +/** + * exynos5_dmc_get_status() - Read current DMC performance statistics. + * @dev: device for which the statistics are requested + * @stat: structure which has statistic fields + * + * Function reads the DMC performance counters and calculates 'busy_time' + * and 'total_time'. To protect from overflow, the values are shifted right + * by 10. After read out the counters are setup to count again. + */ +static int exynos5_dmc_get_status(struct device *dev, + struct devfreq_dev_status *stat) +{ + struct exynos5_dmc *dmc = dev_get_drvdata(dev); + unsigned long load, total; + int ret; + + if (dmc->in_irq_mode) { + mutex_lock(&dmc->lock); + stat->current_frequency = dmc->curr_rate; + mutex_unlock(&dmc->lock); + + stat->busy_time = dmc->load; + stat->total_time = dmc->total; + } else { + ret = exynos5_counters_get(dmc, &load, &total); + if (ret < 0) + return -EINVAL; + + /* To protect from overflow, divide by 1024 */ + stat->busy_time = load >> 10; + stat->total_time = total >> 10; + + ret = exynos5_counters_set_event(dmc); + if (ret < 0) { + dev_err(dev, "could not set event counter\n"); + return ret; + } + } + + return 0; +} + +/** + * exynos5_dmc_get_cur_freq() - Function returns current DMC frequency + * @dev: device for which the framework checks operating frequency + * @freq: returned frequency value + * + * It returns the currently used frequency of the DMC. The real operating + * frequency might be lower when the clock source value could not be divided + * to the requested value. + */ +static int exynos5_dmc_get_cur_freq(struct device *dev, unsigned long *freq) +{ + struct exynos5_dmc *dmc = dev_get_drvdata(dev); + + mutex_lock(&dmc->lock); + *freq = dmc->curr_rate; + mutex_unlock(&dmc->lock); + + return 0; +} + +/* + * exynos5_dmc_df_profile - Devfreq governor's profile structure + * + * It provides to the devfreq framework needed functions and polling period. + */ +static struct devfreq_dev_profile exynos5_dmc_df_profile = { + .timer = DEVFREQ_TIMER_DELAYED, + .target = exynos5_dmc_target, + .get_dev_status = exynos5_dmc_get_status, + .get_cur_freq = exynos5_dmc_get_cur_freq, +}; + +/** + * exynos5_dmc_align_init_freq() - Align initial frequency value + * @dmc: device for which the frequency is going to be set + * @bootloader_init_freq: initial frequency set by the bootloader in KHz + * + * The initial bootloader frequency, which is present during boot, might be + * different that supported frequency values in the driver. It is possible + * due to different PLL settings or used PLL as a source. + * This function provides the 'initial_freq' for the devfreq framework + * statistics engine which supports only registered values. Thus, some alignment + * must be made. + */ +static unsigned long +exynos5_dmc_align_init_freq(struct exynos5_dmc *dmc, + unsigned long bootloader_init_freq) +{ + unsigned long aligned_freq; + int idx; + + idx = find_target_freq_idx(dmc, bootloader_init_freq); + if (idx >= 0) + aligned_freq = dmc->opp[idx].freq_hz; + else + aligned_freq = dmc->opp[dmc->opp_count - 1].freq_hz; + + return aligned_freq; +} + +/** + * create_timings_aligned() - Create register values and align with standard + * @dmc: device for which the frequency is going to be set + * @reg_timing_row: array to fill with values for timing row register + * @reg_timing_data: array to fill with values for timing data register + * @reg_timing_power: array to fill with values for timing power register + * @clk_period_ps: the period of the clock, known as tCK + * + * The function calculates timings and creates a register value ready for + * a frequency transition. The register contains a few timings. They are + * shifted by a known offset. The timing value is calculated based on memory + * specyfication: minimal time required and minimal cycles required. + */ +static int create_timings_aligned(struct exynos5_dmc *dmc, u32 *reg_timing_row, + u32 *reg_timing_data, u32 *reg_timing_power, + u32 clk_period_ps) +{ + u32 val; + const struct timing_reg *reg; + + if (clk_period_ps == 0) + return -EINVAL; + + *reg_timing_row = 0; + *reg_timing_data = 0; + *reg_timing_power = 0; + + val = dmc->timings->tRFC / clk_period_ps; + val += dmc->timings->tRFC % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tRFC); + reg = &timing_row_reg_fields[0]; + *reg_timing_row |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tRRD / clk_period_ps; + val += dmc->timings->tRRD % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tRRD); + reg = &timing_row_reg_fields[1]; + *reg_timing_row |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tRPab / clk_period_ps; + val += dmc->timings->tRPab % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tRPab); + reg = &timing_row_reg_fields[2]; + *reg_timing_row |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tRCD / clk_period_ps; + val += dmc->timings->tRCD % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tRCD); + reg = &timing_row_reg_fields[3]; + *reg_timing_row |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tRC / clk_period_ps; + val += dmc->timings->tRC % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tRC); + reg = &timing_row_reg_fields[4]; + *reg_timing_row |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tRAS / clk_period_ps; + val += dmc->timings->tRAS % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tRAS); + reg = &timing_row_reg_fields[5]; + *reg_timing_row |= TIMING_VAL2REG(reg, val); + + /* data related timings */ + val = dmc->timings->tWTR / clk_period_ps; + val += dmc->timings->tWTR % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tWTR); + reg = &timing_data_reg_fields[0]; + *reg_timing_data |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tWR / clk_period_ps; + val += dmc->timings->tWR % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tWR); + reg = &timing_data_reg_fields[1]; + *reg_timing_data |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tRTP / clk_period_ps; + val += dmc->timings->tRTP % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tRTP); + reg = &timing_data_reg_fields[2]; + *reg_timing_data |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tW2W_C2C / clk_period_ps; + val += dmc->timings->tW2W_C2C % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tW2W_C2C); + reg = &timing_data_reg_fields[3]; + *reg_timing_data |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tR2R_C2C / clk_period_ps; + val += dmc->timings->tR2R_C2C % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tR2R_C2C); + reg = &timing_data_reg_fields[4]; + *reg_timing_data |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tWL / clk_period_ps; + val += dmc->timings->tWL % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tWL); + reg = &timing_data_reg_fields[5]; + *reg_timing_data |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tDQSCK / clk_period_ps; + val += dmc->timings->tDQSCK % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tDQSCK); + reg = &timing_data_reg_fields[6]; + *reg_timing_data |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tRL / clk_period_ps; + val += dmc->timings->tRL % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tRL); + reg = &timing_data_reg_fields[7]; + *reg_timing_data |= TIMING_VAL2REG(reg, val); + + /* power related timings */ + val = dmc->timings->tFAW / clk_period_ps; + val += dmc->timings->tFAW % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tFAW); + reg = &timing_power_reg_fields[0]; + *reg_timing_power |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tXSR / clk_period_ps; + val += dmc->timings->tXSR % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tXSR); + reg = &timing_power_reg_fields[1]; + *reg_timing_power |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tXP / clk_period_ps; + val += dmc->timings->tXP % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tXP); + reg = &timing_power_reg_fields[2]; + *reg_timing_power |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tCKE / clk_period_ps; + val += dmc->timings->tCKE % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tCKE); + reg = &timing_power_reg_fields[3]; + *reg_timing_power |= TIMING_VAL2REG(reg, val); + + val = dmc->timings->tMRD / clk_period_ps; + val += dmc->timings->tMRD % clk_period_ps ? 1 : 0; + val = max(val, dmc->min_tck->tMRD); + reg = &timing_power_reg_fields[4]; + *reg_timing_power |= TIMING_VAL2REG(reg, val); + + return 0; +} + +/** + * of_get_dram_timings() - helper function for parsing DT settings for DRAM + * @dmc: device for which the frequency is going to be set + * + * The function parses DT entries with DRAM information. + */ +static int of_get_dram_timings(struct exynos5_dmc *dmc) +{ + int ret = 0; + int idx; + struct device_node *np_ddr; + u32 freq_mhz, clk_period_ps; + + np_ddr = of_parse_phandle(dmc->dev->of_node, "device-handle", 0); + if (!np_ddr) { + dev_warn(dmc->dev, "could not find 'device-handle' in DT\n"); + return -EINVAL; + } + + dmc->timing_row = devm_kmalloc_array(dmc->dev, TIMING_COUNT, + sizeof(u32), GFP_KERNEL); + if (!dmc->timing_row) { + ret = -ENOMEM; + goto put_node; + } + + dmc->timing_data = devm_kmalloc_array(dmc->dev, TIMING_COUNT, + sizeof(u32), GFP_KERNEL); + if (!dmc->timing_data) { + ret = -ENOMEM; + goto put_node; + } + + dmc->timing_power = devm_kmalloc_array(dmc->dev, TIMING_COUNT, + sizeof(u32), GFP_KERNEL); + if (!dmc->timing_power) { + ret = -ENOMEM; + goto put_node; + } + + dmc->timings = of_lpddr3_get_ddr_timings(np_ddr, dmc->dev, + DDR_TYPE_LPDDR3, + &dmc->timings_arr_size); + if (!dmc->timings) { + dev_warn(dmc->dev, "could not get timings from DT\n"); + ret = -EINVAL; + goto put_node; + } + + dmc->min_tck = of_lpddr3_get_min_tck(np_ddr, dmc->dev); + if (!dmc->min_tck) { + dev_warn(dmc->dev, "could not get tck from DT\n"); + ret = -EINVAL; + goto put_node; + } + + /* Sorted array of OPPs with frequency ascending */ + for (idx = 0; idx < dmc->opp_count; idx++) { + freq_mhz = dmc->opp[idx].freq_hz / 1000000; + clk_period_ps = 1000000 / freq_mhz; + + ret = create_timings_aligned(dmc, &dmc->timing_row[idx], + &dmc->timing_data[idx], + &dmc->timing_power[idx], + clk_period_ps); + } + + + /* Take the highest frequency's timings as 'bypass' */ + dmc->bypass_timing_row = dmc->timing_row[idx - 1]; + dmc->bypass_timing_data = dmc->timing_data[idx - 1]; + dmc->bypass_timing_power = dmc->timing_power[idx - 1]; + +put_node: + of_node_put(np_ddr); + return ret; +} + +/** + * exynos5_dmc_init_clks() - Initialize clocks needed for DMC operation. + * @dmc: DMC structure containing needed fields + * + * Get the needed clocks defined in DT device, enable and set the right parents. + * Read current frequency and initialize the initial rate for governor. + */ +static int exynos5_dmc_init_clks(struct exynos5_dmc *dmc) +{ + int ret; + unsigned long target_volt = 0; + unsigned long target_rate = 0; + unsigned int tmp; + + dmc->fout_spll = devm_clk_get(dmc->dev, "fout_spll"); + if (IS_ERR(dmc->fout_spll)) + return PTR_ERR(dmc->fout_spll); + + dmc->fout_bpll = devm_clk_get(dmc->dev, "fout_bpll"); + if (IS_ERR(dmc->fout_bpll)) + return PTR_ERR(dmc->fout_bpll); + + dmc->mout_mclk_cdrex = devm_clk_get(dmc->dev, "mout_mclk_cdrex"); + if (IS_ERR(dmc->mout_mclk_cdrex)) + return PTR_ERR(dmc->mout_mclk_cdrex); + + dmc->mout_bpll = devm_clk_get(dmc->dev, "mout_bpll"); + if (IS_ERR(dmc->mout_bpll)) + return PTR_ERR(dmc->mout_bpll); + + dmc->mout_mx_mspll_ccore = devm_clk_get(dmc->dev, + "mout_mx_mspll_ccore"); + if (IS_ERR(dmc->mout_mx_mspll_ccore)) + return PTR_ERR(dmc->mout_mx_mspll_ccore); + + dmc->mout_spll = devm_clk_get(dmc->dev, "ff_dout_spll2"); + if (IS_ERR(dmc->mout_spll)) { + dmc->mout_spll = devm_clk_get(dmc->dev, "mout_sclk_spll"); + if (IS_ERR(dmc->mout_spll)) + return PTR_ERR(dmc->mout_spll); + } + + /* + * Convert frequency to KHz values and set it for the governor. + */ + dmc->curr_rate = clk_get_rate(dmc->mout_mclk_cdrex); + dmc->curr_rate = exynos5_dmc_align_init_freq(dmc, dmc->curr_rate); + exynos5_dmc_df_profile.initial_freq = dmc->curr_rate; + + ret = exynos5_dmc_get_volt_freq(dmc, &dmc->curr_rate, &target_rate, + &target_volt, 0); + if (ret) + return ret; + + dmc->curr_volt = target_volt; + + ret = clk_set_parent(dmc->mout_mx_mspll_ccore, dmc->mout_spll); + if (ret) + return ret; + + clk_prepare_enable(dmc->fout_bpll); + clk_prepare_enable(dmc->mout_bpll); + + /* + * Some bootloaders do not set clock routes correctly. + * Stop one path in clocks to PHY. + */ + regmap_read(dmc->clk_regmap, CDREX_LPDDR3PHY_CLKM_SRC, &tmp); + tmp &= ~(BIT(1) | BIT(0)); + regmap_write(dmc->clk_regmap, CDREX_LPDDR3PHY_CLKM_SRC, tmp); + + return 0; +} + +/** + * exynos5_performance_counters_init() - Initializes performance DMC's counters + * @dmc: DMC for which it does the setup + * + * Initialization of performance counters in DMC for estimating usage. + * The counter's values are used for calculation of a memory bandwidth and based + * on that the governor changes the frequency. + * The counters are not used when the governor is GOVERNOR_USERSPACE. + */ +static int exynos5_performance_counters_init(struct exynos5_dmc *dmc) +{ + int ret, i; + + dmc->num_counters = devfreq_event_get_edev_count(dmc->dev, + "devfreq-events"); + if (dmc->num_counters < 0) { + dev_err(dmc->dev, "could not get devfreq-event counters\n"); + return dmc->num_counters; + } + + dmc->counter = devm_kcalloc(dmc->dev, dmc->num_counters, + sizeof(*dmc->counter), GFP_KERNEL); + if (!dmc->counter) + return -ENOMEM; + + for (i = 0; i < dmc->num_counters; i++) { + dmc->counter[i] = + devfreq_event_get_edev_by_phandle(dmc->dev, + "devfreq-events", i); + if (IS_ERR_OR_NULL(dmc->counter[i])) + return -EPROBE_DEFER; + } + + ret = exynos5_counters_enable_edev(dmc); + if (ret < 0) { + dev_err(dmc->dev, "could not enable event counter\n"); + return ret; + } + + ret = exynos5_counters_set_event(dmc); + if (ret < 0) { + exynos5_counters_disable_edev(dmc); + dev_err(dmc->dev, "could not set event counter\n"); + return ret; + } + + return 0; +} + +/** + * exynos5_dmc_set_pause_on_switching() - Controls a pause feature in DMC + * @dmc: device which is used for changing this feature + * + * There is a need of pausing DREX DMC when divider or MUX in clock tree + * changes its configuration. In such situation access to the memory is blocked + * in DMC automatically. This feature is used when clock frequency change + * request appears and touches clock tree. + */ +static inline int exynos5_dmc_set_pause_on_switching(struct exynos5_dmc *dmc) +{ + unsigned int val; + int ret; + + ret = regmap_read(dmc->clk_regmap, CDREX_PAUSE, &val); + if (ret) + return ret; + + val |= 1UL; + regmap_write(dmc->clk_regmap, CDREX_PAUSE, val); + + return 0; +} + +static irqreturn_t dmc_irq_thread(int irq, void *priv) +{ + int res; + struct exynos5_dmc *dmc = priv; + + mutex_lock(&dmc->df->lock); + exynos5_dmc_perf_events_check(dmc); + res = update_devfreq(dmc->df); + mutex_unlock(&dmc->df->lock); + + if (res) + dev_warn(dmc->dev, "devfreq failed with %d\n", res); + + return IRQ_HANDLED; +} + +/** + * exynos5_dmc_probe() - Probe function for the DMC driver + * @pdev: platform device for which the driver is going to be initialized + * + * Initialize basic components: clocks, regulators, performance counters, etc. + * Read out product version and based on the information setup + * internal structures for the controller (frequency and voltage) and for DRAM + * memory parameters: timings for each operating frequency. + * Register new devfreq device for controlling DVFS of the DMC. + */ +static int exynos5_dmc_probe(struct platform_device *pdev) +{ + int ret = 0; + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct exynos5_dmc *dmc; + int irq[2]; + + dmc = devm_kzalloc(dev, sizeof(*dmc), GFP_KERNEL); + if (!dmc) + return -ENOMEM; + + mutex_init(&dmc->lock); + + dmc->dev = dev; + platform_set_drvdata(pdev, dmc); + + dmc->base_drexi0 = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(dmc->base_drexi0)) + return PTR_ERR(dmc->base_drexi0); + + dmc->base_drexi1 = devm_platform_ioremap_resource(pdev, 1); + if (IS_ERR(dmc->base_drexi1)) + return PTR_ERR(dmc->base_drexi1); + + dmc->clk_regmap = syscon_regmap_lookup_by_phandle(np, + "samsung,syscon-clk"); + if (IS_ERR(dmc->clk_regmap)) + return PTR_ERR(dmc->clk_regmap); + + ret = exynos5_init_freq_table(dmc, &exynos5_dmc_df_profile); + if (ret) { + dev_warn(dev, "couldn't initialize frequency settings\n"); + return ret; + } + + dmc->vdd_mif = devm_regulator_get(dev, "vdd"); + if (IS_ERR(dmc->vdd_mif)) { + ret = PTR_ERR(dmc->vdd_mif); + return ret; + } + + ret = exynos5_dmc_init_clks(dmc); + if (ret) + return ret; + + ret = of_get_dram_timings(dmc); + if (ret) { + dev_warn(dev, "couldn't initialize timings settings\n"); + goto remove_clocks; + } + + ret = exynos5_dmc_set_pause_on_switching(dmc); + if (ret) { + dev_warn(dev, "couldn't get access to PAUSE register\n"); + goto remove_clocks; + } + + /* There is two modes in which the driver works: polling or IRQ */ + irq[0] = platform_get_irq_byname(pdev, "drex_0"); + irq[1] = platform_get_irq_byname(pdev, "drex_1"); + if (irq[0] > 0 && irq[1] > 0 && irqmode) { + ret = devm_request_threaded_irq(dev, irq[0], NULL, + dmc_irq_thread, IRQF_ONESHOT, + dev_name(dev), dmc); + if (ret) { + dev_err(dev, "couldn't grab IRQ\n"); + goto remove_clocks; + } + + ret = devm_request_threaded_irq(dev, irq[1], NULL, + dmc_irq_thread, IRQF_ONESHOT, + dev_name(dev), dmc); + if (ret) { + dev_err(dev, "couldn't grab IRQ\n"); + goto remove_clocks; + } + + /* + * Setup default thresholds for the devfreq governor. + * The values are chosen based on experiments. + */ + dmc->gov_data.upthreshold = 55; + dmc->gov_data.downdifferential = 5; + + exynos5_dmc_enable_perf_events(dmc); + + dmc->in_irq_mode = 1; + } else { + ret = exynos5_performance_counters_init(dmc); + if (ret) { + dev_warn(dev, "couldn't probe performance counters\n"); + goto remove_clocks; + } + + /* + * Setup default thresholds for the devfreq governor. + * The values are chosen based on experiments. + */ + dmc->gov_data.upthreshold = 10; + dmc->gov_data.downdifferential = 5; + + exynos5_dmc_df_profile.polling_ms = 100; + } + + dmc->df = devm_devfreq_add_device(dev, &exynos5_dmc_df_profile, + DEVFREQ_GOV_SIMPLE_ONDEMAND, + &dmc->gov_data); + + if (IS_ERR(dmc->df)) { + ret = PTR_ERR(dmc->df); + goto err_devfreq_add; + } + + if (dmc->in_irq_mode) + exynos5_dmc_start_perf_events(dmc, PERF_COUNTER_START_VALUE); + + dev_info(dev, "DMC initialized, in irq mode: %d\n", dmc->in_irq_mode); + + return 0; + +err_devfreq_add: + if (dmc->in_irq_mode) + exynos5_dmc_disable_perf_events(dmc); + else + exynos5_counters_disable_edev(dmc); +remove_clocks: + clk_disable_unprepare(dmc->mout_bpll); + clk_disable_unprepare(dmc->fout_bpll); + + return ret; +} + +/** + * exynos5_dmc_remove() - Remove function for the platform device + * @pdev: platform device which is going to be removed + * + * The function relies on 'devm' framework function which automatically + * clean the device's resources. It just calls explicitly disable function for + * the performance counters. + */ +static int exynos5_dmc_remove(struct platform_device *pdev) +{ + struct exynos5_dmc *dmc = dev_get_drvdata(&pdev->dev); + + if (dmc->in_irq_mode) + exynos5_dmc_disable_perf_events(dmc); + else + exynos5_counters_disable_edev(dmc); + + clk_disable_unprepare(dmc->mout_bpll); + clk_disable_unprepare(dmc->fout_bpll); + + return 0; +} + +static const struct of_device_id exynos5_dmc_of_match[] = { + { .compatible = "samsung,exynos5422-dmc", }, + { }, +}; +MODULE_DEVICE_TABLE(of, exynos5_dmc_of_match); + +static struct platform_driver exynos5_dmc_platdrv = { + .probe = exynos5_dmc_probe, + .remove = exynos5_dmc_remove, + .driver = { + .name = "exynos5-dmc", + .of_match_table = exynos5_dmc_of_match, + }, +}; +module_platform_driver(exynos5_dmc_platdrv); +MODULE_DESCRIPTION("Driver for Exynos5422 Dynamic Memory Controller dynamic frequency and voltage change"); +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Lukasz Luba"); |