[PATCH v7 3/6] clk: qcom: gdsc: Add a reset op to poll gdsc collapse

From: Akhil P Oommen
Date: Wed Oct 05 2022 - 05:08:12 EST


Add a reset op compatible function to poll for gdsc collapse. This is
required because:
1. We don't wait for it to turn OFF at hardware for VOTABLE GDSCs.
2. There is no way for client drivers (eg. gpu driver) to do
put-with-wait for these gdscs which is required in some scenarios
(eg. GPU recovery).

Signed-off-by: Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---

Changes in v7:
- Update commit message (Bjorn)

Changes in v2:
- Minor update to function prototype

drivers/clk/qcom/gdsc.c | 23 +++++++++++++++++++----
drivers/clk/qcom/gdsc.h | 7 +++++++
2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index 7cf5e13..ccef742 100644
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -17,6 +17,7 @@
#include <linux/reset-controller.h>
#include <linux/slab.h>
#include "gdsc.h"
+#include "reset.h"

#define PWR_ON_MASK BIT(31)
#define EN_REST_WAIT_MASK GENMASK_ULL(23, 20)
@@ -116,7 +117,8 @@ static int gdsc_hwctrl(struct gdsc *sc, bool en)
return regmap_update_bits(sc->regmap, sc->gdscr, HW_CONTROL_MASK, val);
}

-static int gdsc_poll_status(struct gdsc *sc, enum gdsc_status status)
+static int gdsc_poll_status(struct gdsc *sc, enum gdsc_status status,
+ s64 timeout_us, unsigned int interval_ms)
{
ktime_t start;

@@ -124,7 +126,9 @@ static int gdsc_poll_status(struct gdsc *sc, enum gdsc_status status)
do {
if (gdsc_check_status(sc, status))
return 0;
- } while (ktime_us_delta(ktime_get(), start) < TIMEOUT_US);
+ if (interval_ms)
+ msleep(interval_ms);
+ } while (ktime_us_delta(ktime_get(), start) < timeout_us);

if (gdsc_check_status(sc, status))
return 0;
@@ -189,7 +193,7 @@ static int gdsc_toggle_logic(struct gdsc *sc, enum gdsc_status status)
udelay(1);
}

- ret = gdsc_poll_status(sc, status);
+ ret = gdsc_poll_status(sc, status, TIMEOUT_US, 0);
WARN(ret, "%s status stuck at 'o%s'", sc->pd.name, status ? "ff" : "n");

if (!ret && status == GDSC_OFF && sc->rsupply) {
@@ -360,7 +364,7 @@ static int _gdsc_disable(struct gdsc *sc)
*/
udelay(1);

- ret = gdsc_poll_status(sc, GDSC_ON);
+ ret = gdsc_poll_status(sc, GDSC_ON, TIMEOUT_US, 0);
if (ret)
return ret;
}
@@ -608,3 +612,14 @@ int gdsc_gx_do_nothing_enable(struct generic_pm_domain *domain)
return 0;
}
EXPORT_SYMBOL_GPL(gdsc_gx_do_nothing_enable);
+
+int gdsc_wait_for_collapse(void *priv)
+{
+ struct gdsc *sc = priv;
+ int ret;
+
+ ret = gdsc_poll_status(sc, GDSC_OFF, 500000, 5);
+ WARN(ret, "%s status stuck at 'on'", sc->pd.name);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(gdsc_wait_for_collapse);
diff --git a/drivers/clk/qcom/gdsc.h b/drivers/clk/qcom/gdsc.h
index 981a12c..5395f69 100644
--- a/drivers/clk/qcom/gdsc.h
+++ b/drivers/clk/qcom/gdsc.h
@@ -12,6 +12,7 @@
struct regmap;
struct regulator;
struct reset_controller_dev;
+struct qcom_reset_map;

/**
* struct gdsc - Globally Distributed Switch Controller
@@ -88,6 +89,7 @@ int gdsc_register(struct gdsc_desc *desc, struct reset_controller_dev *,
struct regmap *);
void gdsc_unregister(struct gdsc_desc *desc);
int gdsc_gx_do_nothing_enable(struct generic_pm_domain *domain);
+int gdsc_wait_for_collapse(void *priv);
#else
static inline int gdsc_register(struct gdsc_desc *desc,
struct reset_controller_dev *rcdev,
@@ -97,5 +99,10 @@ static inline int gdsc_register(struct gdsc_desc *desc,
}

static inline void gdsc_unregister(struct gdsc_desc *desc) {};
+
+static int gdsc_wait_for_collapse(void *priv)
+{
+ return -ENOSYS;
+}
#endif /* CONFIG_QCOM_GDSC */
#endif /* __QCOM_GDSC_H__ */
--
2.7.4