123 lines
3.9 KiB
Diff
123 lines
3.9 KiB
Diff
From 28dc17d0ca6eab000fa477c7143fe5c65d2423e8 Mon Sep 17 00:00:00 2001
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From: Sascha Hauer <s.hauer@pengutronix.de>
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Date: Wed, 24 May 2023 10:31:34 +0200
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Subject: [PATCH 394/414] PM / devfreq: rockchip-dfi: Use free running counter
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The DDR_MON counters are free running counters. These are resetted to 0
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when starting them over like currently done when reading the current
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counter values.
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Resetting the counters becomes a problem with perf support we want to
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add later, because perf needs counters that are not modified elsewhere.
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This patch removes resetting the counters and keeps them running
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instead. That means we no longer use the absolute counter values but
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instead compare them with the counter values we read last time. Not
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stopping the counters also has the impact that they are running while
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we are reading them. We cannot read multiple timers atomically, so
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the values do not exactly fit together. The effect should be negligible
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though as the time between two measurements is some orders of magnitude
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bigger than the time we need to read multiple registers.
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Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
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---
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drivers/devfreq/event/rockchip-dfi.c | 52 ++++++++++++++++------------
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1 file changed, 30 insertions(+), 22 deletions(-)
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--- a/drivers/devfreq/event/rockchip-dfi.c
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+++ b/drivers/devfreq/event/rockchip-dfi.c
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@@ -38,11 +38,15 @@
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#define DDRMON_CH1_COUNT_NUM 0x3c
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#define DDRMON_CH1_DFI_ACCESS_NUM 0x40
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-struct dmc_usage {
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+struct dmc_count_channel {
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u32 access;
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u32 total;
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};
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+struct dmc_count {
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+ struct dmc_count_channel c[RK3399_DMC_NUM_CH];
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+};
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+
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/*
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* The dfi controller can monitor DDR load. It has an upper and lower threshold
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* for the operating points. Whenever the usage leaves these bounds an event is
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@@ -51,7 +55,7 @@ struct dmc_usage {
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struct rockchip_dfi {
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struct devfreq_event_dev *edev;
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struct devfreq_event_desc desc;
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- struct dmc_usage ch_usage[RK3399_DMC_NUM_CH];
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+ struct dmc_count last_event_count;
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struct device *dev;
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void __iomem *regs;
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struct regmap *regmap_pmu;
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@@ -85,30 +89,18 @@ static void rockchip_dfi_stop_hardware_c
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writel_relaxed(SOFTWARE_DIS, dfi_regs + DDRMON_CTRL);
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}
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-static int rockchip_dfi_get_busier_ch(struct devfreq_event_dev *edev)
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+static void rockchip_dfi_read_counters(struct devfreq_event_dev *edev, struct dmc_count *count)
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{
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struct rockchip_dfi *dfi = devfreq_event_get_drvdata(edev);
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- u32 tmp, max = 0;
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- u32 i, busier_ch = 0;
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+ u32 i;
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void __iomem *dfi_regs = dfi->regs;
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- rockchip_dfi_stop_hardware_counter(edev);
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-
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- /* Find out which channel is busier */
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for (i = 0; i < RK3399_DMC_NUM_CH; i++) {
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- dfi->ch_usage[i].access = readl_relaxed(dfi_regs +
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+ count->c[i].access = readl_relaxed(dfi_regs +
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DDRMON_CH0_DFI_ACCESS_NUM + i * 20);
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- dfi->ch_usage[i].total = readl_relaxed(dfi_regs +
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+ count->c[i].total = readl_relaxed(dfi_regs +
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DDRMON_CH0_COUNT_NUM + i * 20);
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- tmp = dfi->ch_usage[i].access;
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- if (tmp > max) {
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- busier_ch = i;
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- max = tmp;
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- }
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}
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- rockchip_dfi_start_hardware_counter(edev);
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-
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- return busier_ch;
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}
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static int rockchip_dfi_disable(struct devfreq_event_dev *edev)
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@@ -145,12 +137,28 @@ static int rockchip_dfi_get_event(struct
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struct devfreq_event_data *edata)
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{
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struct rockchip_dfi *dfi = devfreq_event_get_drvdata(edev);
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- int busier_ch;
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+ struct dmc_count count;
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+ struct dmc_count *last = &dfi->last_event_count;
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+ u32 access = 0, total = 0;
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+ int i;
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+
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+ rockchip_dfi_read_counters(edev, &count);
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+
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+ /* We can only report one channel, so find the busiest one */
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+ for (i = 0; i < RK3399_DMC_NUM_CH; i++) {
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+ u32 a = count.c[i].access - last->c[i].access;
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+ u32 t = count.c[i].total - last->c[i].total;
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+
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+ if (a > access) {
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+ access = a;
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+ total = t;
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+ }
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+ }
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- busier_ch = rockchip_dfi_get_busier_ch(edev);
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+ edata->load_count = access * 4;
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+ edata->total_count = total;
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- edata->load_count = dfi->ch_usage[busier_ch].access * 4;
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- edata->total_count = dfi->ch_usage[busier_ch].total;
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+ dfi->last_event_count = count;
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return 0;
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}
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