[PATCH v4 0/6] clk/qcom: Support gdsc collapse polling using 'reset' interface

[PATCH v4 0/6] clk/qcom: Support gdsc collapse polling using 'reset' interface

[Akhil P Oommen]

Some clients like adreno gpu driver would like to ensure that its gdsc
is collapsed at hardware during a gpu reset sequence. This is because it
has a votable gdsc which could be ON due to a vote from another subsystem
like tz, hyp etc or due to an internal hardware signal. To allow
this, gpucc driver can expose an interface to the client driver using
reset framework. Using this the client driver can trigger a polling within
the gdsc driver.

This series is rebased on top of linus's master branch.

Related discussion: https://patchwork.freedesktop.org/patch/493144/

Changes in v4:
- Update gpu dt-binding schema
- Typo fix in commit text

Changes in v3:
- Use pointer to const for "struct qcom_reset_ops" in qcom_reset_map (Krzysztof)

Changes in v2:
- Return error when a particular custom reset op is not implemented. (Dmitry)

Akhil P Oommen (6):
  dt-bindings: clk: qcom: Support gpu cx gdsc reset
  clk: qcom: Allow custom reset ops
  clk: qcom: gdsc: Add a reset op to poll gdsc collapse
  clk: qcom: gpucc-sc7280: Add cx collapse reset support
  dt-bindings: drm/msm/gpu: Add optional resets
  arm64: dts: qcom: sc7280: Add Reset support for gpu

 .../devicetree/bindings/display/msm/gpu.yaml       |  7 ++++++
 arch/arm64/boot/dts/qcom/sc7280.dtsi               |  3 +++
 drivers/clk/qcom/gdsc.c                            | 23 ++++++++++++++----
 drivers/clk/qcom/gdsc.h                            |  7 ++++++
 drivers/clk/qcom/gpucc-sc7280.c                    | 10 ++++++++
 drivers/clk/qcom/reset.c                           | 27 ++++++++++++++++++++++
 drivers/clk/qcom/reset.h                           |  8 +++++++
 include/dt-bindings/clock/qcom,gpucc-sc7280.h      |  3 +++
 8 files changed, 84 insertions(+), 4 deletions(-)

-- 
2.7.4

[PATCH v4 1/6] dt-bindings: clk: qcom: Support gpu cx gdsc reset

[Akhil P Oommen]

Add necessary definitions in gpucc bindings to ensure gpu cx gdsc collapse
through 'reset' framework for SC7280.

Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---

(no changes since v1)

 include/dt-bindings/clock/qcom,gpucc-sc7280.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/dt-bindings/clock/qcom,gpucc-sc7280.h b/include/dt-bindings/clock/qcom,gpucc-sc7280.h
index 669b23b..843a31b 100644
--- a/include/dt-bindings/clock/qcom,gpucc-sc7280.h
+++ b/include/dt-bindings/clock/qcom,gpucc-sc7280.h
@@ -32,4 +32,7 @@
 #define GPU_CC_CX_GDSC				0
 #define GPU_CC_GX_GDSC				1
 
+/* GPU_CC reset IDs */
+#define GPU_CX_COLLAPSE				0
+
 #endif
-- 
2.7.4

[PATCH v4 2/6] clk: qcom: Allow custom reset ops

[Akhil P Oommen]

Allow soc specific clk drivers to specify a custom reset operation. We
will use this in an upcoming patch to allow gpucc driver to specify a
differet reset operation for cx_gdsc.

Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
---

(no changes since v3)

Changes in v3:
- Use pointer to const for "struct qcom_reset_ops" in qcom_reset_map (Krzysztof)

Changes in v2:
- Return error when a particular custom reset op is not implemented. (Dmitry)

 drivers/clk/qcom/reset.c | 27 +++++++++++++++++++++++++++
 drivers/clk/qcom/reset.h |  8 ++++++++
 2 files changed, 35 insertions(+)

diff --git a/drivers/clk/qcom/reset.c b/drivers/clk/qcom/reset.c
index 819d194..b7ae4a3 100644
--- a/drivers/clk/qcom/reset.c
+++ b/drivers/clk/qcom/reset.c
@@ -13,6 +13,21 @@
 
 static int qcom_reset(struct reset_controller_dev *rcdev, unsigned long id)
 {
+	struct qcom_reset_controller *rst;
+	const struct qcom_reset_map *map;
+
+	rst = to_qcom_reset_controller(rcdev);
+	map = &rst->reset_map[id];
+
+	if (map->ops && map->ops->reset)
+		return map->ops->reset(map->priv);
+	/*
+	 * If custom ops is implemented but just not this callback, return
+	 * error
+	 */
+	else if (map->ops)
+		return -EOPNOTSUPP;
+
 	rcdev->ops->assert(rcdev, id);
 	udelay(1);
 	rcdev->ops->deassert(rcdev, id);
@@ -28,6 +43,12 @@ qcom_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
 
 	rst = to_qcom_reset_controller(rcdev);
 	map = &rst->reset_map[id];
+
+	if (map->ops && map->ops->assert)
+		return map->ops->assert(map->priv);
+	else if (map->ops)
+		return -EOPNOTSUPP;
+
 	mask = BIT(map->bit);
 
 	return regmap_update_bits(rst->regmap, map->reg, mask, mask);
@@ -42,6 +63,12 @@ qcom_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
 
 	rst = to_qcom_reset_controller(rcdev);
 	map = &rst->reset_map[id];
+
+	if (map->ops && map->ops->deassert)
+		return map->ops->deassert(map->priv);
+	else if (map->ops)
+		return -EOPNOTSUPP;
+
 	mask = BIT(map->bit);
 
 	return regmap_update_bits(rst->regmap, map->reg, mask, 0);
diff --git a/drivers/clk/qcom/reset.h b/drivers/clk/qcom/reset.h
index 2a08b5e..f3147eb 100644
--- a/drivers/clk/qcom/reset.h
+++ b/drivers/clk/qcom/reset.h
@@ -8,9 +8,17 @@
 
 #include <linux/reset-controller.h>
 
+struct qcom_reset_ops {
+	int (*reset)(void *priv);
+	int (*assert)(void *priv);
+	int (*deassert)(void *priv);
+};
+
 struct qcom_reset_map {
 	unsigned int reg;
 	u8 bit;
+	const struct qcom_reset_ops *ops;
+	void *priv;
 };
 
 struct regmap;
-- 
2.7.4

Re: [PATCH v4 2/6] clk: qcom: Allow custom reset ops

[Dmitry Baryshkov]

On 19/08/2022 19:40, Akhil P Oommen wrote:
> Allow soc specific clk drivers to specify a custom reset operation. We
> will use this in an upcoming patch to allow gpucc driver to specify a
> differet reset operation for cx_gdsc.
> 
> Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>


-- 
With best wishes
Dmitry

[PATCH v4 3/6] clk: qcom: gdsc: Add a reset op to poll gdsc collapse

[Akhil P Oommen]

Add a reset op compatible function to poll for gdsc collapse.

Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
---

(no changes since v2)

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 44520ef..2d0f1d1 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;
@@ -172,7 +176,7 @@ 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) {
@@ -343,7 +347,7 @@ 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;
 	}
@@ -565,3 +569,14 @@ 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 ad313d7..d484bdb 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
@@ -79,6 +80,7 @@ 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,
@@ -88,5 +90,10 @@ 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

Re: [PATCH v4 3/6] clk: qcom: gdsc: Add a reset op to poll gdsc collapse

[Dmitry Baryshkov]

On 19/08/2022 19:40, Akhil P Oommen wrote:
> Add a reset op compatible function to poll for gdsc collapse.
> 
> Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
-- 
With best wishes
Dmitry

[PATCH v4 4/6] clk: qcom: gpucc-sc7280: Add cx collapse reset support

[Akhil P Oommen]

Allow a consumer driver to poll for cx gdsc collapse through Reset
framework.

Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
---

(no changes since v3)

Changes in v3:
- Convert 'struct qcom_reset_ops cx_gdsc_reset' to 'static const' (Krzysztof)

Changes in v2:
- Minor update to use the updated custom reset ops implementation

 drivers/clk/qcom/gpucc-sc7280.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/clk/qcom/gpucc-sc7280.c b/drivers/clk/qcom/gpucc-sc7280.c
index 9a832f2..fece3f4 100644
--- a/drivers/clk/qcom/gpucc-sc7280.c
+++ b/drivers/clk/qcom/gpucc-sc7280.c
@@ -433,12 +433,22 @@ static const struct regmap_config gpu_cc_sc7280_regmap_config = {
 	.fast_io = true,
 };
 
+static const struct qcom_reset_ops cx_gdsc_reset = {
+	.reset = gdsc_wait_for_collapse,
+};
+
+static const struct qcom_reset_map gpucc_sc7280_resets[] = {
+	[GPU_CX_COLLAPSE] = { .ops = &cx_gdsc_reset, .priv = &cx_gdsc },
+};
+
 static const struct qcom_cc_desc gpu_cc_sc7280_desc = {
 	.config = &gpu_cc_sc7280_regmap_config,
 	.clks = gpu_cc_sc7280_clocks,
 	.num_clks = ARRAY_SIZE(gpu_cc_sc7280_clocks),
 	.gdscs = gpu_cc_sc7180_gdscs,
 	.num_gdscs = ARRAY_SIZE(gpu_cc_sc7180_gdscs),
+	.resets = gpucc_sc7280_resets,
+	.num_resets = ARRAY_SIZE(gpucc_sc7280_resets),
 };
 
 static const struct of_device_id gpu_cc_sc7280_match_table[] = {
-- 
2.7.4

Re: [PATCH v4 4/6] clk: qcom: gpucc-sc7280: Add cx collapse reset support

[Dmitry Baryshkov]

On 19/08/2022 19:40, Akhil P Oommen wrote:
> Allow a consumer driver to poll for cx gdsc collapse through Reset
> framework.
> 
> Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
> ---
> 
> (no changes since v3)
> 
> Changes in v3:
> - Convert 'struct qcom_reset_ops cx_gdsc_reset' to 'static const' (Krzysztof)
> 
> Changes in v2:
> - Minor update to use the updated custom reset ops implementation
> 
>   drivers/clk/qcom/gpucc-sc7280.c | 10 ++++++++++
>   1 file changed, 10 insertions(+)

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
-- 
With best wishes
Dmitry

[PATCH v4 5/6] dt-bindings: drm/msm/gpu: Add optional resets

[Akhil P Oommen]

Add an optional reference to GPUCC reset which can be used to ensure cx
gdsc collapse during gpu recovery.

Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
---

Changes in v4:
- New patch in v4

 Documentation/devicetree/bindings/display/msm/gpu.yaml | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/msm/gpu.yaml b/Documentation/devicetree/bindings/display/msm/gpu.yaml
index 3397bc3..4576b31 100644
--- a/Documentation/devicetree/bindings/display/msm/gpu.yaml
+++ b/Documentation/devicetree/bindings/display/msm/gpu.yaml
@@ -109,6 +109,13 @@ properties:
       For GMU attached devices a phandle to the GMU device that will
       control the power for the GPU.
 
+  resets:
+    maxItems: 1
+
+  reset-names:
+    items:
+      - const: cx_collapse
+
 
 required:
   - compatible
-- 
2.7.4

Re: [PATCH v4 5/6] dt-bindings: drm/msm/gpu: Add optional resets

[Rob Herring]

On Fri, 19 Aug 2022 22:10:44 +0530, Akhil P Oommen wrote:
> Add an optional reference to GPUCC reset which can be used to ensure cx
> gdsc collapse during gpu recovery.
> 
> Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
> ---
> 
> Changes in v4:
> - New patch in v4
> 
>  Documentation/devicetree/bindings/display/msm/gpu.yaml | 7 +++++++
>  1 file changed, 7 insertions(+)
> 

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v4 5/6] dt-bindings: drm/msm/gpu: Add optional resets

[Krzysztof Kozlowski]

On 19/08/2022 19:40, Akhil P Oommen wrote:
>  Documentation/devicetree/bindings/display/msm/gpu.yaml | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/msm/gpu.yaml b/Documentation/devicetree/bindings/display/msm/gpu.yaml
> index 3397bc3..4576b31 100644
> --- a/Documentation/devicetree/bindings/display/msm/gpu.yaml
> +++ b/Documentation/devicetree/bindings/display/msm/gpu.yaml
> @@ -109,6 +109,13 @@ properties:
>        For GMU attached devices a phandle to the GMU device that will
>        control the power for the GPU.
>  
> +  resets:
> +    maxItems: 1
> +
> +  reset-names:
> +    items:
> +      - const: cx_collapse
> +

Just one blank line, not two. You can keep Rob's ack with that change.

>  required:
>    - compatible


Best regards,
Krzysztof

Re: [PATCH v4 5/6] dt-bindings: drm/msm/gpu: Add optional resets

[Akhil P Oommen]

On 8/23/2022 4:41 PM, Krzysztof Kozlowski wrote:
> On 19/08/2022 19:40, Akhil P Oommen wrote:
>>   Documentation/devicetree/bindings/display/msm/gpu.yaml | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/display/msm/gpu.yaml b/Documentation/devicetree/bindings/display/msm/gpu.yaml
>> index 3397bc3..4576b31 100644
>> --- a/Documentation/devicetree/bindings/display/msm/gpu.yaml
>> +++ b/Documentation/devicetree/bindings/display/msm/gpu.yaml
>> @@ -109,6 +109,13 @@ properties:
>>         For GMU attached devices a phandle to the GMU device that will
>>         control the power for the GPU.
>>   
>> +  resets:
>> +    maxItems: 1
>> +
>> +  reset-names:
>> +    items:
>> +      - const: cx_collapse
>> +
> Just one blank line, not two. You can keep Rob's ack with that change.
Sure.

-Akhil.
>>   required:
>>     - compatible
>
> Best regards,
> Krzysztof

[PATCH v4 6/6] arm64: dts: qcom: sc7280: Add Reset support for gpu

[Akhil P Oommen]

Add support for Reset using GPUCC driver for GPU. This helps to ensure
that GPU state is reset by making sure that CX head switch is collapsed.

Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
---

(no changes since v1)

 arch/arm64/boot/dts/qcom/sc7280.dtsi | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/sc7280.dtsi b/arch/arm64/boot/dts/qcom/sc7280.dtsi
index e66fc67..f5257d6 100644
--- a/arch/arm64/boot/dts/qcom/sc7280.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7280.dtsi
@@ -2243,6 +2243,9 @@
 			nvmem-cells = <&gpu_speed_bin>;
 			nvmem-cell-names = "speed_bin";
 
+			resets = <&gpucc GPU_CX_COLLAPSE>;
+			reset-names = "cx_collapse";
+
 			gpu_opp_table: opp-table {
 				compatible = "operating-points-v2";
 
-- 
2.7.4