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 <[email protected]>
Reviewed-by: Dmitry Baryshkov <[email protected]>
---
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
On Wed, 5 Oct 2022 at 11:08, Akhil P Oommen <[email protected]> wrote:
>
> 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).
What puzzles me a bit, who is the typical consumer of the reset.
I looked at patch4 and tried to figure it out, but let's discuss that
in that thread instead. Some more comments, see below.
>
> Signed-off-by: Akhil P Oommen <[email protected]>
> Reviewed-by: Dmitry Baryshkov <[email protected]>
> ---
>
> 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);
Rather than continue to open code this polling loop, would it not make
sense to convert the code into using readx_poll_timeout() (or some of
its friends).
Down the road, this leads to that the msleep() above should become
usleep_range() instead, which seems more correct to me.
>
> 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__ */
Kind regards
Uffe
On 12/7/2022 9:15 PM, Ulf Hansson wrote:
> On Wed, 5 Oct 2022 at 11:08, Akhil P Oommen <[email protected]> wrote:
>> 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).
> What puzzles me a bit, who is the typical consumer of the reset.
>
> I looked at patch4 and tried to figure it out, but let's discuss that
> in that thread instead. Some more comments, see below.
https://patchwork.freedesktop.org/patch/498397/
gpu driver side changes are already merged in upstream. We call this interface during a GPU recovery which is supposed to be a rare event.
>
>> Signed-off-by: Akhil P Oommen <[email protected]>
>> Reviewed-by: Dmitry Baryshkov <[email protected]>
>> ---
>>
>> 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);
> Rather than continue to open code this polling loop, would it not make
> sense to convert the code into using readx_poll_timeout() (or some of
> its friends).
I was going for a minimal code churn to get this mainlined easily. I like the idea, perhaps we can have a refactor patch if there is consensus.
-Akhil.
>
> Down the road, this leads to that the msleep() above should become
> usleep_range() instead, which seems more correct to me.
>
>> 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__ */
> Kind regards
> Uffe
On 12/8/2022 8:32 PM, Akhil P Oommen wrote:
> On 12/7/2022 9:15 PM, Ulf Hansson wrote:
>> On Wed, 5 Oct 2022 at 11:08, Akhil P Oommen <[email protected]> wrote:
>>> 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).
>> What puzzles me a bit, who is the typical consumer of the reset.
>>
>> I looked at patch4 and tried to figure it out, but let's discuss that
>> in that thread instead. Some more comments, see below.
> https://patchwork.freedesktop.org/patch/498397/
> gpu driver side changes are already merged in upstream. We call this interface during a GPU recovery which is supposed to be a rare event.
>>> Signed-off-by: Akhil P Oommen <[email protected]>
>>> Reviewed-by: Dmitry Baryshkov <[email protected]>
>>> ---
>>>
>>> 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);
>> Rather than continue to open code this polling loop, would it not make
>> sense to convert the code into using readx_poll_timeout() (or some of
>> its friends).
> I was going for a minimal code churn to get this mainlined easily. I like the idea, perhaps we can have a refactor patch if there is consensus.
>
> -Akhil.
>> Down the road, this leads to that the msleep() above should become
>> usleep_range() instead, which seems more correct to me.
Btw, we can optimize this a bit more using 'completion' to minimize CPU overhead. But that can wait as this is supposed to be a rarely used path. We don't expect gpu faults often. I would like to see a simpler implementation upstream first.
-Akhil.
>>
>>> 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__ */
>> Kind regards
>> Uffe