diff options
-rw-r--r-- | drivers/memory/samsung/exynos5422-dmc.c | 345 |
1 files changed, 320 insertions, 25 deletions
diff --git a/drivers/memory/samsung/exynos5422-dmc.c b/drivers/memory/samsung/exynos5422-dmc.c index 0fe5f2186139..47dbf6d1789f 100644 --- a/drivers/memory/samsung/exynos5422-dmc.c +++ b/drivers/memory/samsung/exynos5422-dmc.c @@ -8,6 +8,7 @@ #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> @@ -35,6 +36,61 @@ #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 * @@ -85,6 +141,10 @@ struct exynos5_dmc { struct clk *mout_mx_mspll_ccore_phy; 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) \ @@ -654,6 +714,173 @@ static int exynos5_counters_get(struct exynos5_dmc *dmc, } /** + * 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 @@ -669,18 +896,24 @@ static int exynos5_dmc_get_status(struct device *dev, unsigned long load, total; int ret; - ret = exynos5_counters_get(dmc, &load, &total); - if (ret < 0) - return -EINVAL; + if (dmc->in_irq_mode) { + stat->current_frequency = dmc->curr_rate; + 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 in calculation ratios, divide by 1024 */ - stat->busy_time = load >> 10; - stat->total_time = total >> 10; + /* 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; + ret = exynos5_counters_set_event(dmc); + if (ret < 0) { + dev_err(dev, "could not set event counter\n"); + return ret; + } } return 0; @@ -712,7 +945,6 @@ static int exynos5_dmc_get_cur_freq(struct device *dev, unsigned long *freq) * It provides to the devfreq framework needed functions and polling period. */ static struct devfreq_dev_profile exynos5_dmc_df_profile = { - .polling_ms = 500, .target = exynos5_dmc_target, .get_dev_status = exynos5_dmc_get_status, .get_cur_freq = exynos5_dmc_get_cur_freq, @@ -1108,6 +1340,24 @@ static inline int exynos5_dmc_set_pause_on_switching(struct exynos5_dmc *dmc) 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); + if (res) + dev_warn(dmc->dev, "devfreq failed with %d\n", res); + + mutex_unlock(&dmc->df->lock); + + return IRQ_HANDLED; +} + /** * exynos5_dmc_probe() - Probe function for the DMC driver * @pdev: platform device for which the driver is going to be initialized @@ -1125,6 +1375,7 @@ static int exynos5_dmc_probe(struct platform_device *pdev) struct device_node *np = dev->of_node; struct exynos5_dmc *dmc; struct resource *res; + int irq[2]; dmc = devm_kzalloc(dev, sizeof(*dmc), GFP_KERNEL); if (!dmc) @@ -1172,24 +1423,59 @@ static int exynos5_dmc_probe(struct platform_device *pdev) goto remove_clocks; } - ret = exynos5_performance_counters_init(dmc); + ret = exynos5_dmc_set_pause_on_switching(dmc); if (ret) { - dev_warn(dev, "couldn't probe performance counters\n"); + dev_warn(dev, "couldn't get access to PAUSE register\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 err_devfreq_add; + /* 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) { + 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 = 30; + dmc->gov_data.downdifferential = 5; + + exynos5_dmc_df_profile.polling_ms = 500; } - /* - * Setup default thresholds for the devfreq governor. - * The values are chosen based on experiments. - */ - dmc->gov_data.upthreshold = 30; - dmc->gov_data.downdifferential = 5; dmc->df = devm_devfreq_add_device(dev, &exynos5_dmc_df_profile, DEVFREQ_GOV_SIMPLE_ONDEMAND, @@ -1200,12 +1486,18 @@ static int exynos5_dmc_probe(struct platform_device *pdev) goto err_devfreq_add; } + if (dmc->in_irq_mode) + exynos5_dmc_start_perf_events(dmc, PERF_COUNTER_START_VALUE); + dev_info(dev, "DMC initialized\n"); return 0; err_devfreq_add: - exynos5_counters_disable_edev(dmc); + 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); @@ -1225,7 +1517,10 @@ static int exynos5_dmc_remove(struct platform_device *pdev) { struct exynos5_dmc *dmc = dev_get_drvdata(&pdev->dev); - exynos5_counters_disable_edev(dmc); + 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); |