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* [PATCH v14 0/6] Invoke rpmh_flush for non OSI targets
@ 2020-03-26 17:37 Maulik Shah
  2020-03-26 17:37 ` [PATCH v14 1/6] arm64: dts: qcom: sc7180: Add cpuidle low power states Maulik Shah
                   ` (5 more replies)
  0 siblings, 6 replies; 17+ messages in thread
From: Maulik Shah @ 2020-03-26 17:37 UTC (permalink / raw)
  To: swboyd, evgreen, dianders, bjorn.andersson
  Cc: linux-kernel, linux-arm-msm, agross, mka, rnayak, ilina, lsrao,
	Maulik Shah

Changes in v14:
- Address Doug's comments on change 3 from v13
- Drop new APIs for start and end transaction from change 4 in v13
- Update change 4 to use cpu pm notifications instead
- Add [5] as change 5 to enable use of WAKE TCS when ACTIVE TCS count is 0
- Add change 6 to Allow multiple WAKE TCS to be used as ACTIVE TCSes
- First 4 changes can be merged even without change 5 and 6.

Changes in v13:
- Address Stephen's comment to maintain COMPILE_TEST
- Address Doug's comments and add new APIs for start and end transaction

Changes in v12:
- Kconfig change to remove COMPILE_TEST was dropped in v11, reinclude it.

Changes in v11:
- Address Doug's comments on change 2 and 3
- Include change to invalidate TCSes before flush from [4]

Changes in v10:
- Address Evan's comments to update commit message on change 2
- Add Evan's Reviewed by on change 2
- Remove comment from rpmh_flush() related to last CPU invoking it
- Rebase all changes on top of next-20200302

Changes in v9:
- Keep rpmh_flush() to invoke from within cache_lock
- Remove comments related to only last cpu invoking rpmh_flush()

Changes in v8:
- Address Stephen's comments on changes 2 and 3
- Add Reviewed by from Stephen on change 1

Changes in v7:
- Address Srinivas's comments to update commit text
- Add Reviewed by from Srinivas

Changes in v6:
- Drop 1 & 2 changes from v5 as they already landed in maintainer tree
- Drop 3 & 4 changes from v5 as no user at present for power domain in rsc
- Rename subject to appropriate since power domain changes are dropped
- Rebase other changes on top of next-20200221

Changes in v5:
- Add Rob's Acked by on dt-bindings change
- Drop firmware psci change
- Update cpuidle stats in dtsi to follow PC mode
- Include change to update dirty flag when data is updated from [4]
- Add change to invoke rpmh_flush when caches are dirty

Changes in v4:
- Add change to allow hierarchical topology in PC mode
- Drop hierarchical domain idle states converter from v3
- Address Merge sc7180 dtsi change to add low power modes

Changes in v3:
- Address Rob's comment on dt property value
- Address Stephen's comments on rpmh-rsc driver change
- Include sc7180 cpuidle low power mode changes from [1]
- Include hierarchical domain idle states converter change from [2]

Changes in v2:
- Add Stephen's Reviewed-By to the first three patches
- Addressed Stephen's comments on fourth patch
- Include changes to connect rpmh domain to cpuidle and genpds

Resource State Coordinator (RSC) is responsible for powering off/lowering
the requirements from CPU subsystem for the associated hardware like buses,
clocks, and regulators when all CPUs and cluster is powered down.

RSC power domain uses last-man activities provided by genpd framework based
on Ulf Hansoon's patch series[3], when the cluster of CPUs enter deepest
idle states. As a part of domain poweroff, RSC can lower resource state
requirements by flushing the cached sleep and wake state votes for various
resources.

[1] https://patchwork.kernel.org/patch/11218965
[2] https://patchwork.kernel.org/patch/10941671
[3] https://patchwork.kernel.org/project/linux-arm-msm/list/?series=222355
[4] https://patchwork.kernel.org/project/linux-arm-msm/list/?series=236503
[5] https://patchwork.kernel.org/patch/10818129

Maulik Shah (5):
  arm64: dts: qcom: sc7180: Add cpuidle low power states
  soc: qcom: rpmh: Update dirty flag only when data changes
  soc: qcom: rpmh: Invalidate SLEEP and WAKE TCSes before flushing new
    data
  soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches
  soc: qcom: rpmh-rsc: Allow using free WAKE TCS for active request

Raju P.L.S.S.S.N (1):
  soc: qcom: rpmh-rsc: Clear active mode configuration for wake TCS

 arch/arm64/boot/dts/qcom/sc7180.dtsi |  78 ++++++++++++++
 drivers/soc/qcom/rpmh-internal.h     |   8 ++
 drivers/soc/qcom/rpmh-rsc.c          | 203 ++++++++++++++++++++++++++++-------
 drivers/soc/qcom/rpmh.c              |  71 ++++++------
 4 files changed, 280 insertions(+), 80 deletions(-)

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

^ permalink raw reply	[flat|nested] 17+ messages in thread

* [PATCH v14 1/6] arm64: dts: qcom: sc7180: Add cpuidle low power states
  2020-03-26 17:37 [PATCH v14 0/6] Invoke rpmh_flush for non OSI targets Maulik Shah
@ 2020-03-26 17:37 ` Maulik Shah
  2020-03-26 17:37 ` [PATCH v14 2/6] soc: qcom: rpmh: Update dirty flag only when data changes Maulik Shah
                   ` (4 subsequent siblings)
  5 siblings, 0 replies; 17+ messages in thread
From: Maulik Shah @ 2020-03-26 17:37 UTC (permalink / raw)
  To: swboyd, evgreen, dianders, bjorn.andersson
  Cc: linux-kernel, linux-arm-msm, agross, mka, rnayak, ilina, lsrao,
	Maulik Shah, devicetree

Add device bindings for cpuidle states for cpu devices.

Cc: devicetree@vger.kernel.orgi
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Srinivas Rao L <lsrao@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
---
 arch/arm64/boot/dts/qcom/sc7180.dtsi | 78 ++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/sc7180.dtsi b/arch/arm64/boot/dts/qcom/sc7180.dtsi
index 253274d..f5c08ce 100644
--- a/arch/arm64/boot/dts/qcom/sc7180.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180.dtsi
@@ -94,6 +94,9 @@
 			compatible = "arm,armv8";
 			reg = <0x0 0x0>;
 			enable-method = "psci";
+			cpu-idle-states = <&LITTLE_CPU_SLEEP_0
+					   &LITTLE_CPU_SLEEP_1
+					   &CLUSTER_SLEEP_0>;
 			capacity-dmips-mhz = <1024>;
 			dynamic-power-coefficient = <100>;
 			next-level-cache = <&L2_0>;
@@ -113,6 +116,9 @@
 			compatible = "arm,armv8";
 			reg = <0x0 0x100>;
 			enable-method = "psci";
+			cpu-idle-states = <&LITTLE_CPU_SLEEP_0
+					   &LITTLE_CPU_SLEEP_1
+					   &CLUSTER_SLEEP_0>;
 			capacity-dmips-mhz = <1024>;
 			dynamic-power-coefficient = <100>;
 			next-level-cache = <&L2_100>;
@@ -129,6 +135,9 @@
 			compatible = "arm,armv8";
 			reg = <0x0 0x200>;
 			enable-method = "psci";
+			cpu-idle-states = <&LITTLE_CPU_SLEEP_0
+					   &LITTLE_CPU_SLEEP_1
+					   &CLUSTER_SLEEP_0>;
 			capacity-dmips-mhz = <1024>;
 			dynamic-power-coefficient = <100>;
 			next-level-cache = <&L2_200>;
@@ -145,6 +154,9 @@
 			compatible = "arm,armv8";
 			reg = <0x0 0x300>;
 			enable-method = "psci";
+			cpu-idle-states = <&LITTLE_CPU_SLEEP_0
+					   &LITTLE_CPU_SLEEP_1
+					   &CLUSTER_SLEEP_0>;
 			capacity-dmips-mhz = <1024>;
 			dynamic-power-coefficient = <100>;
 			next-level-cache = <&L2_300>;
@@ -161,6 +173,9 @@
 			compatible = "arm,armv8";
 			reg = <0x0 0x400>;
 			enable-method = "psci";
+			cpu-idle-states = <&LITTLE_CPU_SLEEP_0
+					   &LITTLE_CPU_SLEEP_1
+					   &CLUSTER_SLEEP_0>;
 			capacity-dmips-mhz = <1024>;
 			dynamic-power-coefficient = <100>;
 			next-level-cache = <&L2_400>;
@@ -177,6 +192,9 @@
 			compatible = "arm,armv8";
 			reg = <0x0 0x500>;
 			enable-method = "psci";
+			cpu-idle-states = <&LITTLE_CPU_SLEEP_0
+					   &LITTLE_CPU_SLEEP_1
+					   &CLUSTER_SLEEP_0>;
 			capacity-dmips-mhz = <1024>;
 			dynamic-power-coefficient = <100>;
 			next-level-cache = <&L2_500>;
@@ -193,6 +211,9 @@
 			compatible = "arm,armv8";
 			reg = <0x0 0x600>;
 			enable-method = "psci";
+			cpu-idle-states = <&BIG_CPU_SLEEP_0
+					   &BIG_CPU_SLEEP_1
+					   &CLUSTER_SLEEP_0>;
 			capacity-dmips-mhz = <1740>;
 			dynamic-power-coefficient = <405>;
 			next-level-cache = <&L2_600>;
@@ -209,6 +230,9 @@
 			compatible = "arm,armv8";
 			reg = <0x0 0x700>;
 			enable-method = "psci";
+			cpu-idle-states = <&BIG_CPU_SLEEP_0
+					   &BIG_CPU_SLEEP_1
+					   &CLUSTER_SLEEP_0>;
 			capacity-dmips-mhz = <1740>;
 			dynamic-power-coefficient = <405>;
 			next-level-cache = <&L2_700>;
@@ -255,6 +279,60 @@
 				};
 			};
 		};
+
+		idle-states {
+			entry-method = "psci";
+
+			LITTLE_CPU_SLEEP_0: cpu-sleep-0-0 {
+				compatible = "arm,idle-state";
+				idle-state-name = "little-power-down";
+				arm,psci-suspend-param = <0x40000003>;
+				entry-latency-us = <549>;
+				exit-latency-us = <901>;
+				min-residency-us = <1774>;
+				local-timer-stop;
+			};
+
+			LITTLE_CPU_SLEEP_1: cpu-sleep-0-1 {
+				compatible = "arm,idle-state";
+				idle-state-name = "little-rail-power-down";
+				arm,psci-suspend-param = <0x40000004>;
+				entry-latency-us = <702>;
+				exit-latency-us = <915>;
+				min-residency-us = <4001>;
+				local-timer-stop;
+			};
+
+			BIG_CPU_SLEEP_0: cpu-sleep-1-0 {
+				compatible = "arm,idle-state";
+				idle-state-name = "big-power-down";
+				arm,psci-suspend-param = <0x40000003>;
+				entry-latency-us = <523>;
+				exit-latency-us = <1244>;
+				min-residency-us = <2207>;
+				local-timer-stop;
+			};
+
+			BIG_CPU_SLEEP_1: cpu-sleep-1-1 {
+				compatible = "arm,idle-state";
+				idle-state-name = "big-rail-power-down";
+				arm,psci-suspend-param = <0x40000004>;
+				entry-latency-us = <526>;
+				exit-latency-us = <1854>;
+				min-residency-us = <5555>;
+				local-timer-stop;
+			};
+
+			CLUSTER_SLEEP_0: cluster-sleep-0 {
+				compatible = "arm,idle-state";
+				idle-state-name = "cluster-power-down";
+				arm,psci-suspend-param = <0x40003444>;
+				entry-latency-us = <3263>;
+				exit-latency-us = <6562>;
+				min-residency-us = <9926>;
+				local-timer-stop;
+			};
+		};
 	};
 
 	memory@80000000 {
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

^ permalink raw reply	[flat|nested] 17+ messages in thread

* [PATCH v14 2/6] soc: qcom: rpmh: Update dirty flag only when data changes
  2020-03-26 17:37 [PATCH v14 0/6] Invoke rpmh_flush for non OSI targets Maulik Shah
  2020-03-26 17:37 ` [PATCH v14 1/6] arm64: dts: qcom: sc7180: Add cpuidle low power states Maulik Shah
@ 2020-03-26 17:37 ` Maulik Shah
  2020-03-26 17:37 ` [PATCH v14 3/6] soc: qcom: rpmh: Invalidate SLEEP and WAKE TCSes before flushing new data Maulik Shah
                   ` (3 subsequent siblings)
  5 siblings, 0 replies; 17+ messages in thread
From: Maulik Shah @ 2020-03-26 17:37 UTC (permalink / raw)
  To: swboyd, evgreen, dianders, bjorn.andersson
  Cc: linux-kernel, linux-arm-msm, agross, mka, rnayak, ilina, lsrao,
	Maulik Shah

Currently rpmh ctrlr dirty flag is set for all cases regardless of data
is really changed or not. Add changes to update dirty flag when data is
changed to newer values. Update dirty flag everytime when data in batch
cache is updated since rpmh_flush() may get invoked from any CPU instead
of only last CPU going to low power mode.

Also move dirty flag updates to happen from within cache_lock and remove
unnecessary INIT_LIST_HEAD() call and a default case from switch.

Fixes: 600513dfeef3 ("drivers: qcom: rpmh: cache sleep/wake state requests")
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Srinivas Rao L <lsrao@codeaurora.org>
Reviewed-by: Evan Green <evgreen@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
---
 drivers/soc/qcom/rpmh.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
index eb0ded0..03630ae 100644
--- a/drivers/soc/qcom/rpmh.c
+++ b/drivers/soc/qcom/rpmh.c
@@ -119,6 +119,7 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
 {
 	struct cache_req *req;
 	unsigned long flags;
+	u32 old_sleep_val, old_wake_val;
 
 	spin_lock_irqsave(&ctrlr->cache_lock, flags);
 	req = __find_req(ctrlr, cmd->addr);
@@ -133,26 +134,27 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
 
 	req->addr = cmd->addr;
 	req->sleep_val = req->wake_val = UINT_MAX;
-	INIT_LIST_HEAD(&req->list);
 	list_add_tail(&req->list, &ctrlr->cache);
 
 existing:
+	old_sleep_val = req->sleep_val;
+	old_wake_val = req->wake_val;
+
 	switch (state) {
 	case RPMH_ACTIVE_ONLY_STATE:
-		if (req->sleep_val != UINT_MAX)
-			req->wake_val = cmd->data;
-		break;
 	case RPMH_WAKE_ONLY_STATE:
 		req->wake_val = cmd->data;
 		break;
 	case RPMH_SLEEP_STATE:
 		req->sleep_val = cmd->data;
 		break;
-	default:
-		break;
 	}
 
-	ctrlr->dirty = true;
+	ctrlr->dirty = (req->sleep_val != old_sleep_val ||
+			req->wake_val != old_wake_val) &&
+			req->sleep_val != UINT_MAX &&
+			req->wake_val != UINT_MAX;
+
 unlock:
 	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
 
@@ -287,6 +289,7 @@ static void cache_batch(struct rpmh_ctrlr *ctrlr, struct batch_cache_req *req)
 
 	spin_lock_irqsave(&ctrlr->cache_lock, flags);
 	list_add_tail(&req->list, &ctrlr->batch_cache);
+	ctrlr->dirty = true;
 	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
 }
 
@@ -323,6 +326,7 @@ static void invalidate_batch(struct rpmh_ctrlr *ctrlr)
 	list_for_each_entry_safe(req, tmp, &ctrlr->batch_cache, list)
 		kfree(req);
 	INIT_LIST_HEAD(&ctrlr->batch_cache);
+	ctrlr->dirty = true;
 	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
 }
 
@@ -507,7 +511,6 @@ int rpmh_invalidate(const struct device *dev)
 	int ret;
 
 	invalidate_batch(ctrlr);
-	ctrlr->dirty = true;
 
 	do {
 		ret = rpmh_rsc_invalidate(ctrlr_to_drv(ctrlr));
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

^ permalink raw reply	[flat|nested] 17+ messages in thread

* [PATCH v14 3/6] soc: qcom: rpmh: Invalidate SLEEP and WAKE TCSes before flushing new data
  2020-03-26 17:37 [PATCH v14 0/6] Invoke rpmh_flush for non OSI targets Maulik Shah
  2020-03-26 17:37 ` [PATCH v14 1/6] arm64: dts: qcom: sc7180: Add cpuidle low power states Maulik Shah
  2020-03-26 17:37 ` [PATCH v14 2/6] soc: qcom: rpmh: Update dirty flag only when data changes Maulik Shah
@ 2020-03-26 17:37 ` Maulik Shah
  2020-03-26 18:31   ` Doug Anderson
  2020-03-26 17:37 ` [PATCH v14 4/6] soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches Maulik Shah
                   ` (2 subsequent siblings)
  5 siblings, 1 reply; 17+ messages in thread
From: Maulik Shah @ 2020-03-26 17:37 UTC (permalink / raw)
  To: swboyd, evgreen, dianders, bjorn.andersson
  Cc: linux-kernel, linux-arm-msm, agross, mka, rnayak, ilina, lsrao,
	Maulik Shah

TCSes have previously programmed data when rpmh_flush is called.
This can cause old data to trigger along with newly flushed.

Fix this by cleaning SLEEP and WAKE TCSes before new data is flushed.

With this there is no need to invoke rpmh_rsc_invalidate() call from
rpmh_invalidate().

Simplify rpmh_invalidate() by moving invalidate_batch() inside.

Fixes: 600513dfeef3 ("drivers: qcom: rpmh: cache sleep/wake state requests")
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
---
 drivers/soc/qcom/rpmh.c | 41 ++++++++++++++++++-----------------------
 1 file changed, 18 insertions(+), 23 deletions(-)

diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
index 03630ae..5147d82 100644
--- a/drivers/soc/qcom/rpmh.c
+++ b/drivers/soc/qcom/rpmh.c
@@ -317,19 +317,6 @@ static int flush_batch(struct rpmh_ctrlr *ctrlr)
 	return ret;
 }
 
-static void invalidate_batch(struct rpmh_ctrlr *ctrlr)
-{
-	struct batch_cache_req *req, *tmp;
-	unsigned long flags;
-
-	spin_lock_irqsave(&ctrlr->cache_lock, flags);
-	list_for_each_entry_safe(req, tmp, &ctrlr->batch_cache, list)
-		kfree(req);
-	INIT_LIST_HEAD(&ctrlr->batch_cache);
-	ctrlr->dirty = true;
-	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
-}
-
 /**
  * rpmh_write_batch: Write multiple sets of RPMH commands and wait for the
  * batch to finish.
@@ -467,6 +454,13 @@ int rpmh_flush(struct rpmh_ctrlr *ctrlr)
 		return 0;
 	}
 
+	/* Invalidate the TCSes first to avoid stale data */
+	do {
+		ret = rpmh_rsc_invalidate(ctrlr_to_drv(ctrlr));
+	} while (ret == -EAGAIN);
+	if (ret)
+		return ret;
+
 	/* First flush the cached batch requests */
 	ret = flush_batch(ctrlr);
 	if (ret)
@@ -498,24 +492,25 @@ int rpmh_flush(struct rpmh_ctrlr *ctrlr)
 }
 
 /**
- * rpmh_invalidate: Invalidate all sleep and active sets
- * sets.
+ * rpmh_invalidate: Invalidate sleep and active sets in batch_cache
  *
  * @dev: The device making the request
  *
- * Invalidate the sleep and active values in the TCS blocks.
+ * Invalidate the sleep and wake values in batch_cache.
  */
 int rpmh_invalidate(const struct device *dev)
 {
 	struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
-	int ret;
-
-	invalidate_batch(ctrlr);
+	struct batch_cache_req *req, *tmp;
+	unsigned long flags;
 
-	do {
-		ret = rpmh_rsc_invalidate(ctrlr_to_drv(ctrlr));
-	} while (ret == -EAGAIN);
+	spin_lock_irqsave(&ctrlr->cache_lock, flags);
+	list_for_each_entry_safe(req, tmp, &ctrlr->batch_cache, list)
+		kfree(req);
+	INIT_LIST_HEAD(&ctrlr->batch_cache);
+	ctrlr->dirty = true;
+	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
 
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(rpmh_invalidate);
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

^ permalink raw reply	[flat|nested] 17+ messages in thread

* [PATCH v14 4/6] soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches
  2020-03-26 17:37 [PATCH v14 0/6] Invoke rpmh_flush for non OSI targets Maulik Shah
                   ` (2 preceding siblings ...)
  2020-03-26 17:37 ` [PATCH v14 3/6] soc: qcom: rpmh: Invalidate SLEEP and WAKE TCSes before flushing new data Maulik Shah
@ 2020-03-26 17:37 ` Maulik Shah
  2020-03-26 21:18   ` Doug Anderson
  2020-03-26 17:37 ` [PATCH v14 5/6] soc: qcom: rpmh-rsc: Clear active mode configuration for wake TCS Maulik Shah
  2020-03-26 17:37 ` [PATCH v14 6/6] soc: qcom: rpmh-rsc: Allow using free WAKE TCS for active request Maulik Shah
  5 siblings, 1 reply; 17+ messages in thread
From: Maulik Shah @ 2020-03-26 17:37 UTC (permalink / raw)
  To: swboyd, evgreen, dianders, bjorn.andersson
  Cc: linux-kernel, linux-arm-msm, agross, mka, rnayak, ilina, lsrao,
	Maulik Shah

Add changes to invoke rpmh flush() from cpu pm notification.
This is done when last cpu is entering power collapse and
controller is not busy.

Controller that do have 'HW solver' mode do not need to register
for cpu pm notification. They may be in autonomous mode executing
low power mode do not require rpmh_flush() to happen from CPU PM
notification.

Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
---
 drivers/soc/qcom/rpmh-internal.h |  8 ++++
 drivers/soc/qcom/rpmh-rsc.c      | 99 +++++++++++++++++++++++++++++++++++++---
 drivers/soc/qcom/rpmh.c          | 15 ++----
 3 files changed, 103 insertions(+), 19 deletions(-)

diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h
index 6eec32b..33ee50b 100644
--- a/drivers/soc/qcom/rpmh-internal.h
+++ b/drivers/soc/qcom/rpmh-internal.h
@@ -85,22 +85,30 @@ struct rpmh_ctrlr {
  * Resource State Coordinator controller (RSC)
  *
  * @name:       controller identifier
+ * @base:       start address of the RSC's DRV registers
  * @tcs_base:   start address of the TCS registers in this controller
  * @id:         instance id in the controller (Direct Resource Voter)
  * @num_tcs:    number of TCSes in this DRV
+ * @rsc_pm:     CPU PM notifier for controller
+ * @cpus_in_pc: CPU mask for cpus in idle power collapse
  * @tcs:        TCS groups
  * @tcs_in_use: s/w state of the TCS
  * @lock:       synchronize state of the controller
+ * @pm_lock:    synchronize during PM notifications
  * @client:     handle to the DRV's client.
  */
 struct rsc_drv {
 	const char *name;
+	void __iomem *base;
 	void __iomem *tcs_base;
 	int id;
 	int num_tcs;
+	struct notifier_block rsc_pm;
+	struct cpumask cpus_in_pc;
 	struct tcs_group tcs[TCS_TYPE_NR];
 	DECLARE_BITMAP(tcs_in_use, MAX_TCS_NR);
 	spinlock_t lock;
+	spinlock_t pm_lock;
 	struct rpmh_ctrlr client;
 };
 
diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index e278fc1..ee052cc 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -6,6 +6,7 @@
 #define pr_fmt(fmt) "%s " fmt, KBUILD_MODNAME
 
 #include <linux/atomic.h>
+#include <linux/cpu_pm.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
@@ -30,7 +31,12 @@
 #define RSC_DRV_TCS_OFFSET		672
 #define RSC_DRV_CMD_OFFSET		20
 
-/* DRV Configuration Information Register */
+/* DRV HW Solver Configuration Information Register */
+#define DRV_SOLVER_CONFIG		0x04
+#define DRV_HW_SOLVER_MASK		1
+#define DRV_HW_SOLVER_SHIFT		24
+
+/* DRV TCS Configuration Information Register */
 #define DRV_PRNT_CHLD_CONFIG		0x0C
 #define DRV_NUM_TCS_MASK		0x3F
 #define DRV_NUM_TCS_SHIFT		6
@@ -521,6 +527,71 @@ int rpmh_rsc_write_ctrl_data(struct rsc_drv *drv, const struct tcs_request *msg)
 	return tcs_ctrl_write(drv, msg);
 }
 
+/**
+ * rpmh_rsc_ctrlr_is_busy: Check if any of the AMCs are busy.
+ *
+ * @drv: The controller
+ *
+ * Returns True if the TCSes are engaged in handling requests, False otherwise.
+ */
+static bool rpmh_rsc_ctrlr_is_busy(struct rsc_drv *drv)
+{
+	int m;
+	struct tcs_group *tcs = get_tcs_of_type(drv, ACTIVE_TCS);
+
+	/**
+	 * If we made an active request on a RSC that does not have a
+	 * dedicated TCS for active state use, then re-purposed wake TCSes
+	 * should be checked for not busy
+	 */
+	if (!tcs->num_tcs)
+		tcs = get_tcs_of_type(drv, WAKE_TCS);
+
+	for (m = tcs->offset; m < tcs->offset + tcs->num_tcs; m++) {
+		if (!tcs_is_free(drv, m))
+			return true;
+	}
+
+	return false;
+}
+
+static int rpmh_rsc_cpu_pm_callback(struct notifier_block *nfb,
+				    unsigned long action, void *v)
+{
+	struct rsc_drv *drv = container_of(nfb, struct rsc_drv, rsc_pm);
+	unsigned long flags;
+	int ret = NOTIFY_OK;
+
+	spin_lock_irqsave(&drv->pm_lock, flags);
+
+	switch (action) {
+	case CPU_PM_ENTER:
+		cpumask_set_cpu(raw_smp_processor_id(), &drv->cpus_in_pc);
+
+		if (!cpumask_equal(&drv->cpus_in_pc, cpu_online_mask))
+			goto exit;
+		break;
+	case CPU_PM_ENTER_FAILED:
+	case CPU_PM_EXIT:
+		cpumask_clear_cpu(raw_smp_processor_id(), &drv->cpus_in_pc);
+		goto exit;
+	}
+
+	ret = rpmh_rsc_ctrlr_is_busy(drv);
+	if (ret) {
+		ret = NOTIFY_BAD;
+		goto exit;
+	}
+
+	ret = rpmh_flush(&drv->client);
+	if (ret)
+		ret = NOTIFY_BAD;
+
+exit:
+	spin_unlock_irqrestore(&drv->pm_lock, flags);
+	return ret;
+}
+
 static int rpmh_probe_tcs_config(struct platform_device *pdev,
 				 struct rsc_drv *drv)
 {
@@ -533,21 +604,20 @@ static int rpmh_probe_tcs_config(struct platform_device *pdev,
 	int i, ret, n, st = 0;
 	struct tcs_group *tcs;
 	struct resource *res;
-	void __iomem *base;
 	char drv_id[10] = {0};
 
 	snprintf(drv_id, ARRAY_SIZE(drv_id), "drv-%d", drv->id);
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, drv_id);
-	base = devm_ioremap_resource(&pdev->dev, res);
-	if (IS_ERR(base))
-		return PTR_ERR(base);
+	drv->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(drv->base))
+		return PTR_ERR(drv->base);
 
 	ret = of_property_read_u32(dn, "qcom,tcs-offset", &offset);
 	if (ret)
 		return ret;
-	drv->tcs_base = base + offset;
+	drv->tcs_base = drv->base + offset;
 
-	config = readl_relaxed(base + DRV_PRNT_CHLD_CONFIG);
+	config = readl_relaxed(drv->base + DRV_PRNT_CHLD_CONFIG);
 
 	max_tcs = config;
 	max_tcs &= DRV_NUM_TCS_MASK << (DRV_NUM_TCS_SHIFT * drv->id);
@@ -621,6 +691,7 @@ static int rpmh_rsc_probe(struct platform_device *pdev)
 	struct device_node *dn = pdev->dev.of_node;
 	struct rsc_drv *drv;
 	int ret, irq;
+	u32 solver_config;
 
 	/*
 	 * Even though RPMh doesn't directly use cmd-db, all of its children
@@ -663,6 +734,20 @@ static int rpmh_rsc_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	/*
+	 * CPU PM notification are not required for controllers that support
+	 * 'HW solver' mode where they can be in autonomous mode executing low
+	 * power mode to power down.
+	 */
+	solver_config = readl_relaxed(drv->base + DRV_SOLVER_CONFIG);
+	solver_config &= DRV_HW_SOLVER_MASK << DRV_HW_SOLVER_SHIFT;
+	solver_config = solver_config >> DRV_HW_SOLVER_SHIFT;
+	if (!solver_config) {
+		drv->rsc_pm.notifier_call = rpmh_rsc_cpu_pm_callback;
+		cpu_pm_register_notifier(&drv->rsc_pm);
+		spin_lock_init(&drv->pm_lock);
+	}
+
 	/* Enable the active TCS to send requests immediately */
 	write_tcs_reg(drv, RSC_DRV_IRQ_ENABLE, 0, drv->tcs[ACTIVE_TCS].mask);
 
diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
index 5147d82..565b6e4 100644
--- a/drivers/soc/qcom/rpmh.c
+++ b/drivers/soc/qcom/rpmh.c
@@ -297,12 +297,10 @@ static int flush_batch(struct rpmh_ctrlr *ctrlr)
 {
 	struct batch_cache_req *req;
 	const struct rpmh_request *rpm_msg;
-	unsigned long flags;
 	int ret = 0;
 	int i;
 
 	/* Send Sleep/Wake requests to the controller, expect no response */
-	spin_lock_irqsave(&ctrlr->cache_lock, flags);
 	list_for_each_entry(req, &ctrlr->batch_cache, list) {
 		for (i = 0; i < req->count; i++) {
 			rpm_msg = req->rpm_msgs + i;
@@ -312,7 +310,6 @@ static int flush_batch(struct rpmh_ctrlr *ctrlr)
 				break;
 		}
 	}
-	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
 
 	return ret;
 }
@@ -437,12 +434,10 @@ static int send_single(struct rpmh_ctrlr *ctrlr, enum rpmh_state state,
  *
  * @ctrlr: controller making request to flush cached data
  *
- * Return: -EBUSY if the controller is busy, probably waiting on a response
- * to a RPMH request sent earlier.
+ * Return: 0 on success, error number otherwise.
  *
- * This function is always called from the sleep code from the last CPU
- * that is powering down the entire system. Since no other RPMH API would be
- * executing at this time, it is safe to run lockless.
+ * This function can either be called from sleep code on the last CPU
+ * (thus no spinlock needed) or with the ctrlr->cache_lock already held.
  */
 int rpmh_flush(struct rpmh_ctrlr *ctrlr)
 {
@@ -466,10 +461,6 @@ int rpmh_flush(struct rpmh_ctrlr *ctrlr)
 	if (ret)
 		return ret;
 
-	/*
-	 * Nobody else should be calling this function other than system PM,
-	 * hence we can run without locks.
-	 */
 	list_for_each_entry(p, &ctrlr->cache, list) {
 		if (!is_req_valid(p)) {
 			pr_debug("%s: skipping RPMH req: a:%#x s:%#x w:%#x",
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

^ permalink raw reply	[flat|nested] 17+ messages in thread

* [PATCH v14 5/6] soc: qcom: rpmh-rsc: Clear active mode configuration for wake TCS
  2020-03-26 17:37 [PATCH v14 0/6] Invoke rpmh_flush for non OSI targets Maulik Shah
                   ` (3 preceding siblings ...)
  2020-03-26 17:37 ` [PATCH v14 4/6] soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches Maulik Shah
@ 2020-03-26 17:37 ` Maulik Shah
  2020-03-26 18:20   ` Doug Anderson
  2020-03-26 17:37 ` [PATCH v14 6/6] soc: qcom: rpmh-rsc: Allow using free WAKE TCS for active request Maulik Shah
  5 siblings, 1 reply; 17+ messages in thread
From: Maulik Shah @ 2020-03-26 17:37 UTC (permalink / raw)
  To: swboyd, evgreen, dianders, bjorn.andersson
  Cc: linux-kernel, linux-arm-msm, agross, mka, rnayak, ilina, lsrao,
	Raju P.L.S.S.S.N, Maulik Shah

From: "Raju P.L.S.S.S.N" <rplsssn@codeaurora.org>

For RSCs that have sleep & wake TCS but no dedicated active TCS, wake
TCS can be re-purposed to send active requests. Once the active requests
are sent and response is received, the active mode configuration needs
to be cleared so that controller can use wake TCS for sending wake
requests.

Introduce enable_tcs_irq() to enable completion IRQ for repurposed TCSes.

Fixes: 2de4b8d33eab (drivers: qcom: rpmh-rsc: allow active requests from wake TCS)
Signed-off-by: Raju P.L.S.S.S.N <rplsssn@codeaurora.org>
[mkshah: call enable_tcs_irq() within drv->lock, update commit message]
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
---
 drivers/soc/qcom/rpmh-rsc.c | 77 +++++++++++++++++++++++++++++++--------------
 1 file changed, 54 insertions(+), 23 deletions(-)

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index ee052cc..8fa70b4 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -207,6 +207,42 @@ static const struct tcs_request *get_req_from_tcs(struct rsc_drv *drv,
 	return NULL;
 }
 
+static void __tcs_trigger(struct rsc_drv *drv, int tcs_id, bool trigger)
+{
+	u32 enable;
+
+	/*
+	 * HW req: Clear the DRV_CONTROL and enable TCS again
+	 * While clearing ensure that the AMC mode trigger is cleared
+	 * and then the mode enable is cleared.
+	 */
+	enable = read_tcs_reg(drv, RSC_DRV_CONTROL, tcs_id, 0);
+	enable &= ~TCS_AMC_MODE_TRIGGER;
+	write_tcs_reg_sync(drv, RSC_DRV_CONTROL, tcs_id, enable);
+	enable &= ~TCS_AMC_MODE_ENABLE;
+	write_tcs_reg_sync(drv, RSC_DRV_CONTROL, tcs_id, enable);
+
+	if (trigger) {
+		/* Enable the AMC mode on the TCS and then trigger the TCS */
+		enable = TCS_AMC_MODE_ENABLE;
+		write_tcs_reg_sync(drv, RSC_DRV_CONTROL, tcs_id, enable);
+		enable |= TCS_AMC_MODE_TRIGGER;
+		write_tcs_reg_sync(drv, RSC_DRV_CONTROL, tcs_id, enable);
+	}
+}
+
+static void enable_tcs_irq(struct rsc_drv *drv, int tcs_id, bool enable)
+{
+	u32 data;
+
+	data = read_tcs_reg(drv, RSC_DRV_IRQ_ENABLE, 0, 0);
+	if (enable)
+		data |= BIT(tcs_id);
+	else
+		data &= ~BIT(tcs_id);
+	write_tcs_reg(drv, RSC_DRV_IRQ_ENABLE, 0, data);
+}
+
 /**
  * tcs_tx_done: TX Done interrupt handler
  */
@@ -243,6 +279,14 @@ static irqreturn_t tcs_tx_done(int irq, void *p)
 		}
 
 		trace_rpmh_tx_done(drv, i, req, err);
+
+		/*
+		 * If wake tcs was re-purposed for sending active
+		 * votes, clear AMC trigger & enable modes and
+		 * disable interrupt for this TCS
+		 */
+		if (!drv->tcs[ACTIVE_TCS].num_tcs)
+			__tcs_trigger(drv, i, false);
 skip:
 		/* Reclaim the TCS */
 		write_tcs_reg(drv, RSC_DRV_CMD_ENABLE, i, 0);
@@ -250,6 +294,13 @@ static irqreturn_t tcs_tx_done(int irq, void *p)
 		write_tcs_reg(drv, RSC_DRV_IRQ_CLEAR, 0, BIT(i));
 		spin_lock(&drv->lock);
 		clear_bit(i, drv->tcs_in_use);
+		/*
+		 * Disable interrupt for WAKE TCS to avoid being
+		 * spammed with interrupts coming when the solver
+		 * sends its wake votes.
+		 */
+		if (!drv->tcs[ACTIVE_TCS].num_tcs)
+			enable_tcs_irq(drv, i, false);
 		spin_unlock(&drv->lock);
 		if (req)
 			rpmh_tx_done(req, err);
@@ -291,28 +342,6 @@ static void __tcs_buffer_write(struct rsc_drv *drv, int tcs_id, int cmd_id,
 	write_tcs_reg(drv, RSC_DRV_CMD_ENABLE, tcs_id, cmd_enable);
 }
 
-static void __tcs_trigger(struct rsc_drv *drv, int tcs_id)
-{
-	u32 enable;
-
-	/*
-	 * HW req: Clear the DRV_CONTROL and enable TCS again
-	 * While clearing ensure that the AMC mode trigger is cleared
-	 * and then the mode enable is cleared.
-	 */
-	enable = read_tcs_reg(drv, RSC_DRV_CONTROL, tcs_id, 0);
-	enable &= ~TCS_AMC_MODE_TRIGGER;
-	write_tcs_reg_sync(drv, RSC_DRV_CONTROL, tcs_id, enable);
-	enable &= ~TCS_AMC_MODE_ENABLE;
-	write_tcs_reg_sync(drv, RSC_DRV_CONTROL, tcs_id, enable);
-
-	/* Enable the AMC mode on the TCS and then trigger the TCS */
-	enable = TCS_AMC_MODE_ENABLE;
-	write_tcs_reg_sync(drv, RSC_DRV_CONTROL, tcs_id, enable);
-	enable |= TCS_AMC_MODE_TRIGGER;
-	write_tcs_reg_sync(drv, RSC_DRV_CONTROL, tcs_id, enable);
-}
-
 static int check_for_req_inflight(struct rsc_drv *drv, struct tcs_group *tcs,
 				  const struct tcs_request *msg)
 {
@@ -383,10 +412,12 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
 
 	tcs->req[tcs_id - tcs->offset] = msg;
 	set_bit(tcs_id, drv->tcs_in_use);
+	if (msg->state == RPMH_ACTIVE_ONLY_STATE && tcs->type != ACTIVE_TCS)
+		enable_tcs_irq(drv, tcs_id, true);
 	spin_unlock(&drv->lock);
 
 	__tcs_buffer_write(drv, tcs_id, 0, msg);
-	__tcs_trigger(drv, tcs_id);
+	__tcs_trigger(drv, tcs_id, true);
 
 done_write:
 	spin_unlock_irqrestore(&tcs->lock, flags);
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

^ permalink raw reply	[flat|nested] 17+ messages in thread

* [PATCH v14 6/6] soc: qcom: rpmh-rsc: Allow using free WAKE TCS for active request
  2020-03-26 17:37 [PATCH v14 0/6] Invoke rpmh_flush for non OSI targets Maulik Shah
                   ` (4 preceding siblings ...)
  2020-03-26 17:37 ` [PATCH v14 5/6] soc: qcom: rpmh-rsc: Clear active mode configuration for wake TCS Maulik Shah
@ 2020-03-26 17:37 ` Maulik Shah
  2020-03-26 21:46   ` Doug Anderson
  5 siblings, 1 reply; 17+ messages in thread
From: Maulik Shah @ 2020-03-26 17:37 UTC (permalink / raw)
  To: swboyd, evgreen, dianders, bjorn.andersson
  Cc: linux-kernel, linux-arm-msm, agross, mka, rnayak, ilina, lsrao,
	Maulik Shah

When there are more than one WAKE TCS available and there is no dedicated
ACTIVE TCS available, invalidating all WAKE TCSes and waiting for current
transfer to complete in first WAKE TCS blocks using another free WAKE TCS
to complete current request.

Remove rpmh_rsc_invalidate() to happen from tcs_write() when WAKE TCSes
is re-purposed to be used for Active mode. Clear only currently used
WAKE TCS's register configuration.

Mark the caches as dirty so next time when rpmh_flush() is invoked it
can invalidate and program cached sleep and wake sets again.

Fixes: 2de4b8d33eab (drivers: qcom: rpmh-rsc: allow active requests from wake TCS)
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
---
 drivers/soc/qcom/rpmh-rsc.c | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index 8fa70b4..c0513af 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -154,8 +154,9 @@ int rpmh_rsc_invalidate(struct rsc_drv *drv)
 static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv,
 					 const struct tcs_request *msg)
 {
-	int type, ret;
+	int type;
 	struct tcs_group *tcs;
+	unsigned long flags;
 
 	switch (msg->state) {
 	case RPMH_ACTIVE_ONLY_STATE:
@@ -175,18 +176,18 @@ static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv,
 	 * If we are making an active request on a RSC that does not have a
 	 * dedicated TCS for active state use, then re-purpose a wake TCS to
 	 * send active votes.
-	 * NOTE: The driver must be aware that this RSC does not have a
-	 * dedicated AMC, and therefore would invalidate the sleep and wake
-	 * TCSes before making an active state request.
+	 *
+	 * NOTE: Mark caches as dirty here since existing data in wake TCS will
+	 * be lost. rpmh_flush() will processed for dirty caches to restore
+	 * data.
 	 */
 	tcs = get_tcs_of_type(drv, type);
 	if (msg->state == RPMH_ACTIVE_ONLY_STATE && !tcs->num_tcs) {
 		tcs = get_tcs_of_type(drv, WAKE_TCS);
-		if (tcs->num_tcs) {
-			ret = rpmh_rsc_invalidate(drv);
-			if (ret)
-				return ERR_PTR(ret);
-		}
+
+		spin_lock_irqsave(&drv->client.cache_lock, flags);
+		drv->client.dirty = true;
+		spin_unlock_irqrestore(&drv->client.cache_lock, flags);
 	}
 
 	return tcs;
@@ -412,8 +413,16 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
 
 	tcs->req[tcs_id - tcs->offset] = msg;
 	set_bit(tcs_id, drv->tcs_in_use);
-	if (msg->state == RPMH_ACTIVE_ONLY_STATE && tcs->type != ACTIVE_TCS)
+	if (msg->state == RPMH_ACTIVE_ONLY_STATE && tcs->type != ACTIVE_TCS) {
+		/*
+		 * Clear previously programmed WAKE commands in selected
+		 * repurposed TCS to avoid triggering them. tcs->slots will be
+		 * cleaned from rpmh_flush() by invoking rpmh_rsc_invalidate()
+		 */
+		write_tcs_reg_sync(drv, RSC_DRV_CMD_ENABLE, tcs_id, 0);
+		write_tcs_reg_sync(drv, RSC_DRV_CMD_WAIT_FOR_CMPL, tcs_id, 0);
 		enable_tcs_irq(drv, tcs_id, true);
+	}
 	spin_unlock(&drv->lock);
 
 	__tcs_buffer_write(drv, tcs_id, 0, msg);
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

^ permalink raw reply	[flat|nested] 17+ messages in thread

* Re: [PATCH v14 5/6] soc: qcom: rpmh-rsc: Clear active mode configuration for wake TCS
  2020-03-26 17:37 ` [PATCH v14 5/6] soc: qcom: rpmh-rsc: Clear active mode configuration for wake TCS Maulik Shah
@ 2020-03-26 18:20   ` Doug Anderson
  0 siblings, 0 replies; 17+ messages in thread
From: Doug Anderson @ 2020-03-26 18:20 UTC (permalink / raw)
  To: Maulik Shah
  Cc: Stephen Boyd, Evan Green, Bjorn Andersson, LKML, linux-arm-msm,
	Andy Gross, Matthias Kaehlcke, Rajendra Nayak, Lina Iyer, lsrao,
	Raju P.L.S.S.S.N

Hi,

On Thu, Mar 26, 2020 at 10:38 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>
> From: "Raju P.L.S.S.S.N" <rplsssn@codeaurora.org>
>
> For RSCs that have sleep & wake TCS but no dedicated active TCS, wake
> TCS can be re-purposed to send active requests. Once the active requests
> are sent and response is received, the active mode configuration needs
> to be cleared so that controller can use wake TCS for sending wake
> requests.
>
> Introduce enable_tcs_irq() to enable completion IRQ for repurposed TCSes.
>
> Fixes: 2de4b8d33eab (drivers: qcom: rpmh-rsc: allow active requests from wake TCS)
> Signed-off-by: Raju P.L.S.S.S.N <rplsssn@codeaurora.org>
> [mkshah: call enable_tcs_irq() within drv->lock, update commit message]
> Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
> ---
>  drivers/soc/qcom/rpmh-rsc.c | 77 +++++++++++++++++++++++++++++++--------------
>  1 file changed, 54 insertions(+), 23 deletions(-)

I was writing my review of v1 at the same time you sent this.  Looks
like your patch does address the most important piece of feedback I
had (adjusting the interrupt enable under spinlock), but some of the
other feedback might be nice to incorporate:

https://lore.kernel.org/r/CAD=FV=XmBQb8yfx14T-tMQ68F-h=3UHog744b3X3JZViu15+4g@mail.gmail.com

-Doug

^ permalink raw reply	[flat|nested] 17+ messages in thread

* Re: [PATCH v14 3/6] soc: qcom: rpmh: Invalidate SLEEP and WAKE TCSes before flushing new data
  2020-03-26 17:37 ` [PATCH v14 3/6] soc: qcom: rpmh: Invalidate SLEEP and WAKE TCSes before flushing new data Maulik Shah
@ 2020-03-26 18:31   ` Doug Anderson
  2020-03-27  8:23     ` Maulik Shah
  0 siblings, 1 reply; 17+ messages in thread
From: Doug Anderson @ 2020-03-26 18:31 UTC (permalink / raw)
  To: Maulik Shah
  Cc: Stephen Boyd, Evan Green, Bjorn Andersson, LKML, linux-arm-msm,
	Andy Gross, Matthias Kaehlcke, Rajendra Nayak, Lina Iyer, lsrao

Hi,

On Thu, Mar 26, 2020 at 10:38 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>
>  /**
> - * rpmh_invalidate: Invalidate all sleep and active sets
> - * sets.
> + * rpmh_invalidate: Invalidate sleep and active sets in batch_cache

s/and active/and wake/

...with that, feel free to add my Reviewed-by tag.

-Doug

^ permalink raw reply	[flat|nested] 17+ messages in thread

* Re: [PATCH v14 4/6] soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches
  2020-03-26 17:37 ` [PATCH v14 4/6] soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches Maulik Shah
@ 2020-03-26 21:18   ` Doug Anderson
       [not found]     ` <7bd2c923-4003-a1c4-610f-548e79a94d35@codeaurora.org>
  0 siblings, 1 reply; 17+ messages in thread
From: Doug Anderson @ 2020-03-26 21:18 UTC (permalink / raw)
  To: Maulik Shah
  Cc: Stephen Boyd, Evan Green, Bjorn Andersson, LKML, linux-arm-msm,
	Andy Gross, Matthias Kaehlcke, Rajendra Nayak, Lina Iyer, lsrao

Hi,

On Thu, Mar 26, 2020 at 10:38 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>
> Add changes to invoke rpmh flush() from cpu pm notification.
> This is done when last cpu is entering power collapse and

s/when last/when the last/

> controller is not busy.

A few overall comments:

* CPU_PM certainly seems interesting and I wasn't aware of it.

* Your series is predicated on nobody calling any of the RPMH
functions after the last CPU enters low power mode with CPU_PM_ENTER
and before some CPU calls CPU_PM_EXIT.  Is it worth adding a check for
that to the code?  This is super important for the 'zero-active-TCS'
case but even for the 'some-active-TCS' it's still important that
nobody tries to update the sleep/wake values after you flush.

* I think your series is focused on idle, right?  What about
suspend/resume?  You need a flush before suspend, right?  Do you need
to register for something to handle suspend, or do the pm callbacks
all get called for full system suspend?  If so, how late do they get
called?


> Controller that do have 'HW solver' mode do not need to register

s/Controller/Controllers


> @@ -85,22 +85,30 @@ struct rpmh_ctrlr {
>   * Resource State Coordinator controller (RSC)
>   *
>   * @name:       controller identifier
> + * @base:       start address of the RSC's DRV registers
>   * @tcs_base:   start address of the TCS registers in this controller
>   * @id:         instance id in the controller (Direct Resource Voter)
>   * @num_tcs:    number of TCSes in this DRV
> + * @rsc_pm:     CPU PM notifier for controller
> + * @cpus_in_pc: CPU mask for cpus in idle power collapse

Name "cpus_entered_pm" to match Linux naming?  Also the comment should
clearly say that this is only used in non-solver mode.


>   * @tcs:        TCS groups
>   * @tcs_in_use: s/w state of the TCS
>   * @lock:       synchronize state of the controller
> + * @pm_lock:    synchronize during PM notifications

Comment should say that this is only for non-solver mode.


> @@ -521,6 +527,71 @@ int rpmh_rsc_write_ctrl_data(struct rsc_drv *drv, const struct tcs_request *msg)
>         return tcs_ctrl_write(drv, msg);
>  }
>
> +/**
> + * rpmh_rsc_ctrlr_is_busy: Check if any of the AMCs are busy.
> + *
> + * @drv: The controller
> + *
> + * Returns True if the TCSes are engaged in handling requests, False otherwise.

This is almost, but not quite in kernel-doc syntax.  Why not make it
match the example in "Documentation/doc-guide/kernel-doc.rst"?
Specifically trying to follow that style:

 * rpmh_rsc_ctrlr_is_busy() - Check if any of the AMCs are busy.
 * @drv: The controller
 *
 * Return: true if TCSes are engaged in handling requests; else false


> +static bool rpmh_rsc_ctrlr_is_busy(struct rsc_drv *drv)
> +{
> +       int m;
> +       struct tcs_group *tcs = get_tcs_of_type(drv, ACTIVE_TCS);
> +
> +       /**

nit: why double star in "/**"?  That's for kerneldoc comments.  I
don't think it makes sense here...


> +        * If we made an active request on a RSC that does not have a
> +        * dedicated TCS for active state use, then re-purposed wake TCSes
> +        * should be checked for not busy
> +        */
> +       if (!tcs->num_tcs)
> +               tcs = get_tcs_of_type(drv, WAKE_TCS);
> +
> +       for (m = tcs->offset; m < tcs->offset + tcs->num_tcs; m++) {
> +               if (!tcs_is_free(drv, m))

As per my documentation patch, tcs_is_free():

 * Must be called with the drv->lock held or the tcs_lock for the TCS being
 * tested.

...I think you're OK calling without the lock since you're running on
the last CPU (and you're blocking any other CPUs from coming online)
and interrupts are disabled, but please document.


> +static int rpmh_rsc_cpu_pm_callback(struct notifier_block *nfb,
> +                                   unsigned long action, void *v)
> +{
> +       struct rsc_drv *drv = container_of(nfb, struct rsc_drv, rsc_pm);
> +       unsigned long flags;
> +       int ret = NOTIFY_OK;
> +
> +       spin_lock_irqsave(&drv->pm_lock, flags);

nit: you can get away with just spin_lock().  cpu_pm_enter() is
documented to be called with interrupts already disabled so the
"irqsave" and "irqrestore" is useless.


> +       switch (action) {
> +       case CPU_PM_ENTER:
> +               cpumask_set_cpu(raw_smp_processor_id(), &drv->cpus_in_pc);
> +
> +               if (!cpumask_equal(&drv->cpus_in_pc, cpu_online_mask))

Is it ever possible to offline a CPU after doing "CPU_PM_ENTER" on it?
 If so you'll never be "equal" to the online mask again.  This seems
safer:

!cpumask_subset(cpu_online_mask, &drv->cpus_in_pc)


> +                       goto exit;
> +               break;
> +       case CPU_PM_ENTER_FAILED:
> +       case CPU_PM_EXIT:
> +               cpumask_clear_cpu(raw_smp_processor_id(), &drv->cpus_in_pc);
> +               goto exit;
> +       }
> +
> +       ret = rpmh_rsc_ctrlr_is_busy(drv);
> +       if (ret) {
> +               ret = NOTIFY_BAD;
> +               goto exit;
> +       }

Are you sure you can't just skip the call to rpmh_rsc_ctrlr_is_busy()?
 Specifically, I'm not sure why you need to block until the last
active mode transaction is done.

a) If the active mode transaction was on its own TCS, I'd hope that
the RPMH hardware would know to let the active transitions happen
before triggering the sleep (please confirm)

b) If the active mode transaction was borrowing the wake TCS the flush
should notice and return NOTIFY_BAD anyway.

Oh!  ...but looking closer at case b) points out a problem anyway.
You need to go into rpmh_flush() and stop having it loop on 'while
(ret == -EAGAIN)".  As per my documentation series (please review)
when -EAGAIN is returned it's important that the caller enable
interrupts for a little while before trying again.  You're not doing
that here.  Maybe if you fix it then you can get rid of your special
case rpmh_rsc_ctrlr_is_busy()?


> +       ret = rpmh_flush(&drv->client);

Back when RPMH first landed we had a whole argument about whether it
should be one file or two.  Given that it's currently two files, I
think the abstraction is that rpmh-rsc generally doesn't call into
rpmh except for the very special rpmh_tx_done().

...so seems like the whole pm_callback should move into rpmh.c and not
in rpmh-rsc.c?


> @@ -533,21 +604,20 @@ static int rpmh_probe_tcs_config(struct platform_device *pdev,
>         int i, ret, n, st = 0;
>         struct tcs_group *tcs;
>         struct resource *res;
> -       void __iomem *base;
>         char drv_id[10] = {0};
>
>         snprintf(drv_id, ARRAY_SIZE(drv_id), "drv-%d", drv->id);
>         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, drv_id);
> -       base = devm_ioremap_resource(&pdev->dev, res);
> -       if (IS_ERR(base))
> -               return PTR_ERR(base);
> +       drv->base = devm_ioremap_resource(&pdev->dev, res);
> +       if (IS_ERR(drv->base))
> +               return PTR_ERR(drv->base);

I don't understand this part of the change.  Why move "base" into the
driver data.  It's not needed after probe.  Please undo this.  If you
really feel like base needs to be separate please move to its own
patch.


> @@ -663,6 +734,20 @@ static int rpmh_rsc_probe(struct platform_device *pdev)
>         if (ret)
>                 return ret;
>
> +       /*
> +        * CPU PM notification are not required for controllers that support
> +        * 'HW solver' mode where they can be in autonomous mode executing low
> +        * power mode to power down.
> +        */
> +       solver_config = readl_relaxed(drv->base + DRV_SOLVER_CONFIG);
> +       solver_config &= DRV_HW_SOLVER_MASK << DRV_HW_SOLVER_SHIFT;
> +       solver_config = solver_config >> DRV_HW_SOLVER_SHIFT;
> +       if (!solver_config) {
> +               drv->rsc_pm.notifier_call = rpmh_rsc_cpu_pm_callback;
> +               cpu_pm_register_notifier(&drv->rsc_pm);
> +               spin_lock_init(&drv->pm_lock);

nit: init the spin lock before registering instead of after.


>   * @ctrlr: controller making request to flush cached data
>   *
> - * Return: -EBUSY if the controller is busy, probably waiting on a response
> - * to a RPMH request sent earlier.
> + * Return: 0 on success, error number otherwise.
>   *
> - * This function is always called from the sleep code from the last CPU
> - * that is powering down the entire system. Since no other RPMH API would be
> - * executing at this time, it is safe to run lockless.
> + * This function can either be called from sleep code on the last CPU
> + * (thus no spinlock needed) or with the ctrlr->cache_lock already held.

Now you can remove the "or with the ctrlr->cache_lock already held"
since it's no longer true.


-Doug

^ permalink raw reply	[flat|nested] 17+ messages in thread

* Re: [PATCH v14 6/6] soc: qcom: rpmh-rsc: Allow using free WAKE TCS for active request
  2020-03-26 17:37 ` [PATCH v14 6/6] soc: qcom: rpmh-rsc: Allow using free WAKE TCS for active request Maulik Shah
@ 2020-03-26 21:46   ` Doug Anderson
  2020-03-27 12:04     ` Maulik Shah
  0 siblings, 1 reply; 17+ messages in thread
From: Doug Anderson @ 2020-03-26 21:46 UTC (permalink / raw)
  To: Maulik Shah
  Cc: Stephen Boyd, Evan Green, Bjorn Andersson, LKML, linux-arm-msm,
	Andy Gross, Matthias Kaehlcke, Rajendra Nayak, Lina Iyer, lsrao

Hi,

On Thu, Mar 26, 2020 at 10:38 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>
> When there are more than one WAKE TCS available and there is no dedicated
> ACTIVE TCS available, invalidating all WAKE TCSes and waiting for current
> transfer to complete in first WAKE TCS blocks using another free WAKE TCS
> to complete current request.
>
> Remove rpmh_rsc_invalidate() to happen from tcs_write() when WAKE TCSes
> is re-purposed to be used for Active mode. Clear only currently used
> WAKE TCS's register configuration.
>
> Mark the caches as dirty so next time when rpmh_flush() is invoked it
> can invalidate and program cached sleep and wake sets again.
>
> Fixes: 2de4b8d33eab (drivers: qcom: rpmh-rsc: allow active requests from wake TCS)
> Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
> ---
>  drivers/soc/qcom/rpmh-rsc.c | 29 +++++++++++++++++++----------
>  1 file changed, 19 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
> index 8fa70b4..c0513af 100644
> --- a/drivers/soc/qcom/rpmh-rsc.c
> +++ b/drivers/soc/qcom/rpmh-rsc.c
> @@ -154,8 +154,9 @@ int rpmh_rsc_invalidate(struct rsc_drv *drv)
>  static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv,
>                                          const struct tcs_request *msg)
>  {
> -       int type, ret;
> +       int type;
>         struct tcs_group *tcs;
> +       unsigned long flags;
>
>         switch (msg->state) {
>         case RPMH_ACTIVE_ONLY_STATE:
> @@ -175,18 +176,18 @@ static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv,
>          * If we are making an active request on a RSC that does not have a
>          * dedicated TCS for active state use, then re-purpose a wake TCS to
>          * send active votes.
> -        * NOTE: The driver must be aware that this RSC does not have a
> -        * dedicated AMC, and therefore would invalidate the sleep and wake
> -        * TCSes before making an active state request.
> +        *
> +        * NOTE: Mark caches as dirty here since existing data in wake TCS will
> +        * be lost. rpmh_flush() will processed for dirty caches to restore
> +        * data.
>          */
>         tcs = get_tcs_of_type(drv, type);
>         if (msg->state == RPMH_ACTIVE_ONLY_STATE && !tcs->num_tcs) {
>                 tcs = get_tcs_of_type(drv, WAKE_TCS);
> -               if (tcs->num_tcs) {
> -                       ret = rpmh_rsc_invalidate(drv);
> -                       if (ret)
> -                               return ERR_PTR(ret);
> -               }
> +
> +               spin_lock_irqsave(&drv->client.cache_lock, flags);
> +               drv->client.dirty = true;
> +               spin_unlock_irqrestore(&drv->client.cache_lock, flags);

This seems like a huge abstraction violation.  Why can't rpmh_write()
/ rpmh_write_async() / rpmh_write_batch() just always unconditionally
mark the cache dirty?  Are there really lots of cases when those calls
are made and they do nothing?


Other than that this patch seems sane to me and addresses one of the
comments I had in:

https://lore.kernel.org/r/CAD=FV=XmBQb8yfx14T-tMQ68F-h=3UHog744b3X3JZViu15+4g@mail.gmail.com

...interestingly after your patch I guess now I guess tcs_invalidate()
no longer needs spinlocks since it's only ever called from PM code on
the last CPU.  ...if you agree, I can always do it in my cleanup
series.  See:

https://lore.kernel.org/r/CAD=FV=Xp1o68HnC2-hMnffDDsi+jjgc9pNrdNuypjQZbS5K4nQ@mail.gmail.com

-Doug

^ permalink raw reply	[flat|nested] 17+ messages in thread

* Re: [PATCH v14 3/6] soc: qcom: rpmh: Invalidate SLEEP and WAKE TCSes before flushing new data
  2020-03-26 18:31   ` Doug Anderson
@ 2020-03-27  8:23     ` Maulik Shah
  0 siblings, 0 replies; 17+ messages in thread
From: Maulik Shah @ 2020-03-27  8:23 UTC (permalink / raw)
  To: Doug Anderson
  Cc: Stephen Boyd, Evan Green, Bjorn Andersson, LKML, linux-arm-msm,
	Andy Gross, Matthias Kaehlcke, Rajendra Nayak, Lina Iyer, lsrao

Hi,

On 3/27/2020 12:01 AM, Doug Anderson wrote:
> Hi,
>
> On Thu, Mar 26, 2020 at 10:38 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>>  /**
>> - * rpmh_invalidate: Invalidate all sleep and active sets
>> - * sets.
>> + * rpmh_invalidate: Invalidate sleep and active sets in batch_cache
> s/and active/and wake/
>
> ...with that, feel free to add my Reviewed-by tag.
>
> -Doug

Thankd Doug for the review. I will update this in v15.

Thanks,
Maulik

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

^ permalink raw reply	[flat|nested] 17+ messages in thread

* Re: [PATCH v14 6/6] soc: qcom: rpmh-rsc: Allow using free WAKE TCS for active request
  2020-03-26 21:46   ` Doug Anderson
@ 2020-03-27 12:04     ` Maulik Shah
  2020-03-27 18:42       ` Doug Anderson
  0 siblings, 1 reply; 17+ messages in thread
From: Maulik Shah @ 2020-03-27 12:04 UTC (permalink / raw)
  To: Doug Anderson
  Cc: Stephen Boyd, Evan Green, Bjorn Andersson, LKML, linux-arm-msm,
	Andy Gross, Matthias Kaehlcke, Rajendra Nayak, Lina Iyer, lsrao

Hi,

On 3/27/2020 3:16 AM, Doug Anderson wrote:
> Hi,
>
> On Thu, Mar 26, 2020 at 10:38 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>> When there are more than one WAKE TCS available and there is no dedicated
>> ACTIVE TCS available, invalidating all WAKE TCSes and waiting for current
>> transfer to complete in first WAKE TCS blocks using another free WAKE TCS
>> to complete current request.
>>
>> Remove rpmh_rsc_invalidate() to happen from tcs_write() when WAKE TCSes
>> is re-purposed to be used for Active mode. Clear only currently used
>> WAKE TCS's register configuration.
>>
>> Mark the caches as dirty so next time when rpmh_flush() is invoked it
>> can invalidate and program cached sleep and wake sets again.
>>
>> Fixes: 2de4b8d33eab (drivers: qcom: rpmh-rsc: allow active requests from wake TCS)
>> Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
>> ---
>>  drivers/soc/qcom/rpmh-rsc.c | 29 +++++++++++++++++++----------
>>  1 file changed, 19 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
>> index 8fa70b4..c0513af 100644
>> --- a/drivers/soc/qcom/rpmh-rsc.c
>> +++ b/drivers/soc/qcom/rpmh-rsc.c
>> @@ -154,8 +154,9 @@ int rpmh_rsc_invalidate(struct rsc_drv *drv)
>>  static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv,
>>                                          const struct tcs_request *msg)
>>  {
>> -       int type, ret;
>> +       int type;
>>         struct tcs_group *tcs;
>> +       unsigned long flags;
>>
>>         switch (msg->state) {
>>         case RPMH_ACTIVE_ONLY_STATE:
>> @@ -175,18 +176,18 @@ static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv,
>>          * If we are making an active request on a RSC that does not have a
>>          * dedicated TCS for active state use, then re-purpose a wake TCS to
>>          * send active votes.
>> -        * NOTE: The driver must be aware that this RSC does not have a
>> -        * dedicated AMC, and therefore would invalidate the sleep and wake
>> -        * TCSes before making an active state request.
>> +        *
>> +        * NOTE: Mark caches as dirty here since existing data in wake TCS will
>> +        * be lost. rpmh_flush() will processed for dirty caches to restore
>> +        * data.
>>          */
>>         tcs = get_tcs_of_type(drv, type);
>>         if (msg->state == RPMH_ACTIVE_ONLY_STATE && !tcs->num_tcs) {
>>                 tcs = get_tcs_of_type(drv, WAKE_TCS);
>> -               if (tcs->num_tcs) {
>> -                       ret = rpmh_rsc_invalidate(drv);
>> -                       if (ret)
>> -                               return ERR_PTR(ret);
>> -               }
>> +
>> +               spin_lock_irqsave(&drv->client.cache_lock, flags);
>> +               drv->client.dirty = true;
>> +               spin_unlock_irqrestore(&drv->client.cache_lock, flags);
> This seems like a huge abstraction violation.  

Agree that cache_lock and dirty flag are used in rpmh.c

I will address this to either notify rpmh.c to mark it dirty or think of other solution.

> Why can't rpmh_write()
> / rpmh_write_async() / rpmh_write_batch() just always unconditionally
> mark the cache dirty?  Are there really lots of cases when those calls
> are made and they do nothing?

At rpmh.c, it doesn't know that rpmh-rsc.c worked on borrowed TCS to finish the request.

We should not blindly mark caches dirty everytime.

>
>
> Other than that this patch seems sane to me and addresses one of the
> comments I had in:
>
> https://lore.kernel.org/r/CAD=FV=XmBQb8yfx14T-tMQ68F-h=3UHog744b3X3JZViu15+4g@mail.gmail.com
>
> ...interestingly after your patch I guess now I guess tcs_invalidate()
> no longer needs spinlocks since it's only ever called from PM code on
> the last CPU.  ...if you agree, I can always do it in my cleanup
> series.  See:
>
> https://lore.kernel.org/r/CAD=FV=Xp1o68HnC2-hMnffDDsi+jjgc9pNrdNuypjQZbS5K4nQ@mail.gmail.com
>
> -Doug

There are other RSCs which use same driver, so lets keep spinlock.

I still didn't get chance to validate your patch (i will have update sometime next week), just to update I have never seen any issue internally

using spin_lock even on nosmp case, that might require it to change to _irq_save/restore variant.

Thanks,
Maulik

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

^ permalink raw reply	[flat|nested] 17+ messages in thread

* Re: [PATCH v14 4/6] soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches
       [not found]     ` <7bd2c923-4003-a1c4-610f-548e79a94d35@codeaurora.org>
@ 2020-03-27 18:22       ` Doug Anderson
  2020-03-31  8:26         ` Maulik Shah
  0 siblings, 1 reply; 17+ messages in thread
From: Doug Anderson @ 2020-03-27 18:22 UTC (permalink / raw)
  To: Maulik Shah
  Cc: Stephen Boyd, Evan Green, Bjorn Andersson, LKML, linux-arm-msm,
	Andy Gross, Matthias Kaehlcke, Rajendra Nayak, Lina Iyer, lsrao

Hi,

On Fri, Mar 27, 2020 at 4:00 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>
>   * @ctrlr: controller making request to flush cached data
>   *
> - * Return: -EBUSY if the controller is busy, probably waiting on a response
> - * to a RPMH request sent earlier.
> + * Return: 0 on success, error number otherwise.
>   *
> - * This function is always called from the sleep code from the last CPU
> - * that is powering down the entire system. Since no other RPMH API would be
> - * executing at this time, it is safe to run lockless.
> + * This function can either be called from sleep code on the last CPU
> + * (thus no spinlock needed) or with the ctrlr->cache_lock already held.
>
> Now you can remove the "or with the ctrlr->cache_lock already held"
> since it's no longer true.
>
> It can be true for other RSCs, so i kept as it is.

I don't really understand this.  The cache_lock is only a concept in
"rpmh.c".  How could another RSC grab the cache lock?  If nothing
else, can you remove this comment until support for those other RSCs
are added and we can evaluate then?

-Doug

^ permalink raw reply	[flat|nested] 17+ messages in thread

* Re: [PATCH v14 6/6] soc: qcom: rpmh-rsc: Allow using free WAKE TCS for active request
  2020-03-27 12:04     ` Maulik Shah
@ 2020-03-27 18:42       ` Doug Anderson
  2020-03-31  8:57         ` Maulik Shah
  0 siblings, 1 reply; 17+ messages in thread
From: Doug Anderson @ 2020-03-27 18:42 UTC (permalink / raw)
  To: Maulik Shah
  Cc: Stephen Boyd, Evan Green, Bjorn Andersson, LKML, linux-arm-msm,
	Andy Gross, Matthias Kaehlcke, Rajendra Nayak, Lina Iyer, lsrao

Hi,

On Fri, Mar 27, 2020 at 5:04 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>
> > Why can't rpmh_write()
> > / rpmh_write_async() / rpmh_write_batch() just always unconditionally
> > mark the cache dirty?  Are there really lots of cases when those calls
> > are made and they do nothing?
>
> At rpmh.c, it doesn't know that rpmh-rsc.c worked on borrowed TCS to finish the request.
>
> We should not blindly mark caches dirty everytime.

In message ID "5a5274ac-41f4-b06d-ff49-c00cef67aa7f@codeaurora.org"
which seems to be missing from the archives, you said:

> yes we should trust callers not to send duplicate data

...you can see some reference to it in my reply:

https://lore.kernel.org/r/CAD=FV=VPSahhK71k_D+nfL1=5QE5sKMQT=6zzyEF7+JWMcTxsg@mail.gmail.com/

If callers are trusted to never send duplicate data then ever call to
rpmh_write() will make a change.  ...and thus the cache should always
be marked dirty, no?  Also note that since rpmh_write() to "active"
also counts as a write to "wake" even those will dirty the cache.

Which case are you expecting a rpmh_write() call to not dirty the cache?


> > ...interestingly after your patch I guess now I guess tcs_invalidate()
> > no longer needs spinlocks since it's only ever called from PM code on
> > the last CPU.  ...if you agree, I can always do it in my cleanup
> > series.  See:
> >
> > https://lore.kernel.org/r/CAD=FV=Xp1o68HnC2-hMnffDDsi+jjgc9pNrdNuypjQZbS5K4nQ@mail.gmail.com
> >
> > -Doug
>
> There are other RSCs which use same driver, so lets keep spinlock.

It is really hard to try to write keeping in mind these "other RSCs"
for which there is no code upstream.  IMO we should write the code
keeping in mind what is supported upstream and then when those "other
RSCs" get added we can evaluate their needs.

Specifically when reasoning about rpmh.c and rpmh-rsc.c I can only
look at the code that's there now and decide whether it is race free
or there are races.  Back when I was analyzing the proposal to do
rpmh_flush() all the time (not from PM code) it felt like there were a
bunch of races, especially in the zero-active-TCS case.  Most of the
races go away when you assume that rpmh_flush() is only ever called
from the PM code when nobody could be in the middle of an active
transfer.

If we are ever planning to call rpmh_flush() from another place we
need to re-look at all those races.


-Doug

^ permalink raw reply	[flat|nested] 17+ messages in thread

* Re: [PATCH v14 4/6] soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches
  2020-03-27 18:22       ` Doug Anderson
@ 2020-03-31  8:26         ` Maulik Shah
  0 siblings, 0 replies; 17+ messages in thread
From: Maulik Shah @ 2020-03-31  8:26 UTC (permalink / raw)
  To: Doug Anderson
  Cc: Stephen Boyd, Evan Green, Bjorn Andersson, LKML, linux-arm-msm,
	Andy Gross, Matthias Kaehlcke, Rajendra Nayak, Lina Iyer, lsrao

Hi,

On 3/27/2020 11:52 PM, Doug Anderson wrote:
> Hi,
>
> On Fri, Mar 27, 2020 at 4:00 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>>    * @ctrlr: controller making request to flush cached data
>>    *
>> - * Return: -EBUSY if the controller is busy, probably waiting on a response
>> - * to a RPMH request sent earlier.
>> + * Return: 0 on success, error number otherwise.
>>    *
>> - * This function is always called from the sleep code from the last CPU
>> - * that is powering down the entire system. Since no other RPMH API would be
>> - * executing at this time, it is safe to run lockless.
>> + * This function can either be called from sleep code on the last CPU
>> + * (thus no spinlock needed) or with the ctrlr->cache_lock already held.
>>
>> Now you can remove the "or with the ctrlr->cache_lock already held"
>> since it's no longer true.
>>
>> It can be true for other RSCs, so i kept as it is.
> I don't really understand this.  The cache_lock is only a concept in
> "rpmh.c".  How could another RSC grab the cache lock?  If nothing
> else, can you remove this comment until support for those other RSCs
> are added and we can evaluate then?
>
> -Doug
Okay i will remove this comment until support for other RSCs are added.

Thanks,
Maulik

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

^ permalink raw reply	[flat|nested] 17+ messages in thread

* Re: [PATCH v14 6/6] soc: qcom: rpmh-rsc: Allow using free WAKE TCS for active request
  2020-03-27 18:42       ` Doug Anderson
@ 2020-03-31  8:57         ` Maulik Shah
  0 siblings, 0 replies; 17+ messages in thread
From: Maulik Shah @ 2020-03-31  8:57 UTC (permalink / raw)
  To: Doug Anderson
  Cc: Stephen Boyd, Evan Green, Bjorn Andersson, LKML, linux-arm-msm,
	Andy Gross, Matthias Kaehlcke, Rajendra Nayak, Lina Iyer, lsrao

Hi,

On 3/28/2020 12:12 AM, Doug Anderson wrote:
> Hi,
>
> On Fri, Mar 27, 2020 at 5:04 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>>> Why can't rpmh_write()
>>> / rpmh_write_async() / rpmh_write_batch() just always unconditionally
>>> mark the cache dirty?  Are there really lots of cases when those calls
>>> are made and they do nothing?
>> At rpmh.c, it doesn't know that rpmh-rsc.c worked on borrowed TCS to finish the request.
>>
>> We should not blindly mark caches dirty everytime.
> In message ID "5a5274ac-41f4-b06d-ff49-c00cef67aa7f@codeaurora.org"
> which seems to be missing from the archives, you said:
>
>> yes we should trust callers not to send duplicate data
> ...you can see some reference to it in my reply:
>
> https://lore.kernel.org/r/CAD=FV=VPSahhK71k_D+nfL1=5QE5sKMQT=6zzyEF7+JWMcTxsg@mail.gmail.com/
>
> If callers are trusted to never send duplicate data then ever call to
> rpmh_write() will make a change.  ...and thus the cache should always
> be marked dirty, no?  Also note that since rpmh_write() to "active"
> also counts as a write to "wake" even those will dirty the cache.
>
> Which case are you expecting a rpmh_write() call to not dirty the cache?
Ok, i will remove marking cache dirty here.
>
>
>>> ...interestingly after your patch I guess now I guess tcs_invalidate()
>>> no longer needs spinlocks since it's only ever called from PM code on
>>> the last CPU.  ...if you agree, I can always do it in my cleanup
>>> series.  See:
>>>
>>> https://lore.kernel.org/r/CAD=FV=Xp1o68HnC2-hMnffDDsi+jjgc9pNrdNuypjQZbS5K4nQ@mail.gmail.com
>>>
>>> -Doug
>> There are other RSCs which use same driver, so lets keep spinlock.
> It is really hard to try to write keeping in mind these "other RSCs"
> for which there is no code upstream.  IMO we should write the code
> keeping in mind what is supported upstream and then when those "other
> RSCs" get added we can evaluate their needs.

Agree but i would insist not remove locks in your cleanup/documentation 
series which are already there.

These will be again need to be added.

The locks don't cause any issue being there since only last cpu is 
invoking rpmh_flush() at present.

Adding support for other RSCs is in my to do list, and when that is 
being done we can re-evaluate and

remove if not required.

>
> Specifically when reasoning about rpmh.c and rpmh-rsc.c I can only
> look at the code that's there now and decide whether it is race free
> or there are races.  Back when I was analyzing the proposal to do
> rpmh_flush() all the time (not from PM code) it felt like there were a
> bunch of races, especially in the zero-active-TCS case.  Most of the
> races go away when you assume that rpmh_flush() is only ever called
> from the PM code when nobody could be in the middle of an active
> transfer.
>
> If we are ever planning to call rpmh_flush() from another place we
> need to re-look at all those races.
Sure. we can re-look all cases.
>
>
> -Doug
Thanks,
Maulik

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

^ permalink raw reply	[flat|nested] 17+ messages in thread

end of thread, back to index

Thread overview: 17+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-26 17:37 [PATCH v14 0/6] Invoke rpmh_flush for non OSI targets Maulik Shah
2020-03-26 17:37 ` [PATCH v14 1/6] arm64: dts: qcom: sc7180: Add cpuidle low power states Maulik Shah
2020-03-26 17:37 ` [PATCH v14 2/6] soc: qcom: rpmh: Update dirty flag only when data changes Maulik Shah
2020-03-26 17:37 ` [PATCH v14 3/6] soc: qcom: rpmh: Invalidate SLEEP and WAKE TCSes before flushing new data Maulik Shah
2020-03-26 18:31   ` Doug Anderson
2020-03-27  8:23     ` Maulik Shah
2020-03-26 17:37 ` [PATCH v14 4/6] soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches Maulik Shah
2020-03-26 21:18   ` Doug Anderson
     [not found]     ` <7bd2c923-4003-a1c4-610f-548e79a94d35@codeaurora.org>
2020-03-27 18:22       ` Doug Anderson
2020-03-31  8:26         ` Maulik Shah
2020-03-26 17:37 ` [PATCH v14 5/6] soc: qcom: rpmh-rsc: Clear active mode configuration for wake TCS Maulik Shah
2020-03-26 18:20   ` Doug Anderson
2020-03-26 17:37 ` [PATCH v14 6/6] soc: qcom: rpmh-rsc: Allow using free WAKE TCS for active request Maulik Shah
2020-03-26 21:46   ` Doug Anderson
2020-03-27 12:04     ` Maulik Shah
2020-03-27 18:42       ` Doug Anderson
2020-03-31  8:57         ` Maulik Shah

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