[PATCH v6 14/26] PM / devfreq: rockchip-dfi: Prepare for multiple users

Sascha Hauer
2023-06-16T06:26:36Z

When adding perf support later the DFI must be enabled when
either of devfreq-event or perf is active. Prepare for that
by adding a usage counter for the DFI. Also move enabling
and disabling of the clock away from the devfreq-event specific
functions to which the perf specific part won't have access.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20230524083153.2046084-15-s.hauer@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
drivers/devfreq/event/rockchip-dfi.c | 57 +++++++++++++++++++---------
1 file changed, 40 insertions(+), 17 deletions(-)

diff --git a/drivers/devfreq/event/rockchip-dfi.c b/drivers/devfreq/event/rockchip-dfi.c
index d39db5de7f19c..8a7af7c32ae0d 100644
--- a/drivers/devfreq/event/rockchip-dfi.c
+++ b/drivers/devfreq/event/rockchip-dfi.c
@@ -68,13 +68,28 @@ struct rockchip_dfi {
void __iomem *regs;
struct regmap *regmap_pmu;
struct clk *clk;
+ int usecount;
+ struct mutex mutex;
u32 ddr_type;
unsigned int channel_mask;
};

-static void rockchip_dfi_start_hardware_counter(struct rockchip_dfi *dfi)
+static int rockchip_dfi_enable(struct rockchip_dfi *dfi)
{
void __iomem *dfi_regs = dfi->regs;
+ int ret = 0;
+
+ mutex_lock(&dfi->mutex);
+
+ dfi->usecount++;
+ if (dfi->usecount > 1)
+ goto out;
+
+ ret = clk_prepare_enable(dfi->clk);
+ if (ret) {
+ dev_err(&dfi->edev->dev, "failed to enable dfi clk: %d\n", ret);
+ goto out;
+ }

/* clear DDRMON_CTRL setting */
writel_relaxed(HIWORD_UPDATE(0, DDRMON_CTRL_TIMER_CNT_EN | DDRMON_CTRL_SOFTWARE_EN |
@@ -99,14 +114,30 @@ static void rockchip_dfi_start_hardware_counter(struct rockchip_dfi *dfi)
/* enable count, use software mode */
writel_relaxed(HIWORD_UPDATE(DDRMON_CTRL_SOFTWARE_EN, DDRMON_CTRL_SOFTWARE_EN),
dfi_regs + DDRMON_CTRL);
+out:
+ mutex_unlock(&dfi->mutex);
+
+ return ret;
}

-static void rockchip_dfi_stop_hardware_counter(struct rockchip_dfi *dfi)
+static void rockchip_dfi_disable(struct rockchip_dfi *dfi)
{
void __iomem *dfi_regs = dfi->regs;

+ mutex_lock(&dfi->mutex);
+
+ dfi->usecount--;
+
+ WARN_ON_ONCE(dfi->usecount < 0);
+
+ if (dfi->usecount > 0)
+ goto out;
+
writel_relaxed(HIWORD_UPDATE(0, DDRMON_CTRL_SOFTWARE_EN),
dfi_regs + DDRMON_CTRL);
+ clk_disable_unprepare(dfi->clk);
+out:
+ mutex_unlock(&dfi->mutex);
}

static void rockchip_dfi_read_counters(struct rockchip_dfi *dfi, struct dmc_count *count)
@@ -124,29 +155,20 @@ static void rockchip_dfi_read_counters(struct rockchip_dfi *dfi, struct dmc_coun
}
}

-static int rockchip_dfi_disable(struct devfreq_event_dev *edev)
+static int rockchip_dfi_event_disable(struct devfreq_event_dev *edev)
{
struct rockchip_dfi *dfi = devfreq_event_get_drvdata(edev);

- rockchip_dfi_stop_hardware_counter(dfi);
- clk_disable_unprepare(dfi->clk);
+ rockchip_dfi_disable(dfi);

return 0;
}

-static int rockchip_dfi_enable(struct devfreq_event_dev *edev)
+static int rockchip_dfi_event_enable(struct devfreq_event_dev *edev)
{
struct rockchip_dfi *dfi = devfreq_event_get_drvdata(edev);
- int ret;
-
- ret = clk_prepare_enable(dfi->clk);
- if (ret) {
- dev_err(&edev->dev, "failed to enable dfi clk: %d\n", ret);
- return ret;
- }

- rockchip_dfi_start_hardware_counter(dfi);
- return 0;
+ return rockchip_dfi_enable(dfi);
}

static int rockchip_dfi_set_event(struct devfreq_event_dev *edev)
@@ -190,8 +212,8 @@ static int rockchip_dfi_get_event(struct devfreq_event_dev *edev,
}

static const struct devfreq_event_ops rockchip_dfi_ops = {
- .disable = rockchip_dfi_disable,
- .enable = rockchip_dfi_enable,
+ .disable = rockchip_dfi_event_disable,
+ .enable = rockchip_dfi_event_enable,
.get_event = rockchip_dfi_get_event,
.set_event = rockchip_dfi_set_event,
};
@@ -272,6 +294,7 @@ static int rockchip_dfi_probe(struct platform_device *pdev)
return PTR_ERR(dfi->regmap_pmu);

dfi->dev = dev;
+ mutex_init(&dfi->mutex);

desc = &dfi->desc;
desc->ops = &rockchip_dfi_ops;
--
2.39.2