[PATCH v3 0/3] drivers/qcom: add additional functionality to RPMH

[PATCH v3 0/3] drivers/qcom: add additional functionality to RPMH

[Raju P.L.S.S.S.N]

Changes in v3:
 - Simplify TCS locking - added a new patch
 - Add lock check to avoid potential race as suggested by Matthias
 - Add functionality to RSC controller to disallow active requests
   if solver mode is not set 
 - Removed independent patches and posted as separate series[2]

Changes in v2:
 - Remove unnecessary EXPORT_SYMBOL in rpmh-rsc

This set of patches add additional functionality to RPMH drivers[1].

PM drivers can choose to disallow idle modes when RSC controller is busy
sending or processing requests. The patches add necessary functions to
query the controller status.

The controllers may be in 'solver' state, where they could be in autonomous
mode executing low power modes for their hardware and as such are not
available for sending active votes. Functionality to get notified about
such state and disallow requests for state change in that case is added
in these patches.

Please consider reviewing this patchset.

This series is based on other patchset[2] 


v1:https://lkml.org/lkml/2018/7/19/213
v2:https://patchwork.kernel.org/cover/10546863/



[1] https://lkml.org/lkml/2018/6/20/519
[2] https://lkml.org/lkml/2018/10/3/422


Lina Iyer (2):
  drivers: qcom: rpmh-rsc: return if the controller is idle
  drivers: qcom: rpmh: disallow active requests in solver mode

Raju P.L.S.S.S.N (1):
  drivers: qcom: rpmh-rsc: simplify TCS locking

 drivers/soc/qcom/rpmh-internal.h |  8 +++-
 drivers/soc/qcom/rpmh-rsc.c      | 92 +++++++++++++++++++++++++++++-----------
 drivers/soc/qcom/rpmh.c          | 84 ++++++++++++++++++++++++++++++------
 include/soc/qcom/rpmh.h          | 10 +++++
 4 files changed, 156 insertions(+), 38 deletions(-)

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

[PATCH v3 1/3] drivers: qcom: rpmh-rsc: simplify TCS locking

[Raju P.L.S.S.S.N]

tcs->lock was introduced to serialize access with in TCS group. But
even without tcs->lock, drv->lock is serving the same purpose. So
use single drv->lock.

Other optimizations include -
 - Remove locking around clear_bit() in IRQ handler. clear_bit() is
   atomic.
 - Remove redundant read of TCS registers.
 - Use spin_lock instead of _irq variants as the locks are not held
   in interrupt context

Suggested-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Raju P.L.S.S.S.N <rplsssn@codeaurora.org>
---
This patch is based on https://lkml.org/lkml/2018/10/3/422
---
 drivers/soc/qcom/rpmh-internal.h |  2 --
 drivers/soc/qcom/rpmh-rsc.c      | 37 +++++++++++++------------------------
 drivers/soc/qcom/rpmh.c          | 20 ++++++++------------
 3 files changed, 21 insertions(+), 38 deletions(-)

diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h
index 8c316b4..2e3ffcd 100644
--- a/drivers/soc/qcom/rpmh-internal.h
+++ b/drivers/soc/qcom/rpmh-internal.h
@@ -28,7 +28,6 @@
  * @offset:    start of the TCS group relative to the TCSes in the RSC
  * @num_tcs:   number of TCSes in this type
  * @ncpt:      number of commands in each TCS
- * @lock:      lock for synchronizing this TCS writes
  * @req:       requests that are sent from the TCS
  * @cmd_cache: flattened cache of cmds in sleep/wake TCS
  * @slots:     indicates which of @cmd_addr are occupied
@@ -40,7 +39,6 @@ struct tcs_group {
 	u32 offset;
 	int num_tcs;
 	int ncpt;
-	spinlock_t lock;
 	const struct tcs_request *req[MAX_TCS_PER_TYPE];
 	u32 *cmd_cache;
 	DECLARE_BITMAP(slots, MAX_TCS_SLOTS);
diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index 73d5b98..d6b834e 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -98,8 +98,7 @@ static void write_tcs_reg_sync(struct rsc_drv *drv, int reg, int tcs_id,
 
 static bool tcs_is_free(struct rsc_drv *drv, int tcs_id)
 {
-	return !test_bit(tcs_id, drv->tcs_in_use) &&
-	       read_tcs_reg(drv, RSC_DRV_STATUS, tcs_id, 0);
+	return !test_bit(tcs_id, drv->tcs_in_use);
 }
 
 static struct tcs_group *get_tcs_of_type(struct rsc_drv *drv, int type)
@@ -109,29 +108,28 @@ static struct tcs_group *get_tcs_of_type(struct rsc_drv *drv, int type)
 
 static int tcs_invalidate(struct rsc_drv *drv, int type)
 {
-	int m;
+	int m, ret = 0;
 	struct tcs_group *tcs;
 
 	tcs = get_tcs_of_type(drv, type);
 
-	spin_lock(&tcs->lock);
-	if (bitmap_empty(tcs->slots, MAX_TCS_SLOTS)) {
-		spin_unlock(&tcs->lock);
-		return 0;
-	}
+	spin_lock(&drv->lock);
+	if (bitmap_empty(tcs->slots, MAX_TCS_SLOTS))
+		goto done;
 
 	for (m = tcs->offset; m < tcs->offset + tcs->num_tcs; m++) {
 		if (!tcs_is_free(drv, m)) {
-			spin_unlock(&tcs->lock);
-			return -EAGAIN;
+			ret = -EAGAIN;
+			goto done;
 		}
 		write_tcs_reg_sync(drv, RSC_DRV_CMD_ENABLE, m, 0);
 		write_tcs_reg_sync(drv, RSC_DRV_CMD_WAIT_FOR_CMPL, m, 0);
 	}
 	bitmap_zero(tcs->slots, MAX_TCS_SLOTS);
-	spin_unlock(&tcs->lock);
 
-	return 0;
+done:
+	spin_unlock(&drv->lock);
+	return ret;
 }
 
 /**
@@ -298,9 +296,7 @@ static irqreturn_t tcs_tx_done(int irq, void *p)
 		write_tcs_reg(drv, RSC_DRV_CMD_ENABLE, i, 0);
 		write_tcs_reg(drv, RSC_DRV_CMD_WAIT_FOR_CMPL, i, 0);
 		write_tcs_reg(drv, RSC_DRV_IRQ_CLEAR, 0, BIT(i));
-		spin_lock(&drv->lock);
 		clear_bit(i, drv->tcs_in_use);
-		spin_unlock(&drv->lock);
 		if (req)
 			rpmh_tx_done(req, err);
 	}
@@ -383,14 +379,12 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
 {
 	struct tcs_group *tcs;
 	int tcs_id;
-	unsigned long flags;
 	int ret;
 
 	tcs = get_tcs_for_msg(drv, msg);
 	if (IS_ERR(tcs))
 		return PTR_ERR(tcs);
 
-	spin_lock_irqsave(&tcs->lock, flags);
 	spin_lock(&drv->lock);
 	/*
 	 * The h/w does not like if we send a request to the same address,
@@ -398,14 +392,12 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
 	 */
 	ret = check_for_req_inflight(drv, tcs, msg);
 	if (ret) {
-		spin_unlock(&drv->lock);
 		goto done_write;
 	}
 
 	tcs_id = find_free_tcs(tcs);
 	if (tcs_id < 0) {
 		ret = tcs_id;
-		spin_unlock(&drv->lock);
 		goto done_write;
 	}
 
@@ -413,13 +405,12 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *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, true);
 
 done_write:
-	spin_unlock_irqrestore(&tcs->lock, flags);
+	spin_unlock(&drv->lock);
 	return ret;
 }
 
@@ -517,19 +508,18 @@ static int tcs_ctrl_write(struct rsc_drv *drv, const struct tcs_request *msg)
 {
 	struct tcs_group *tcs;
 	int tcs_id = 0, cmd_id = 0;
-	unsigned long flags;
 	int ret;
 
 	tcs = get_tcs_for_msg(drv, msg);
 	if (IS_ERR(tcs))
 		return PTR_ERR(tcs);
 
-	spin_lock_irqsave(&tcs->lock, flags);
+	spin_lock(&drv->lock);
 	/* find the TCS id and the command in the TCS to write to */
 	ret = find_slots(tcs, msg, &tcs_id, &cmd_id);
 	if (!ret)
 		__tcs_buffer_write(drv, tcs_id, cmd_id, msg);
-	spin_unlock_irqrestore(&tcs->lock, flags);
+	spin_unlock(&drv->lock);
 
 	return ret;
 }
@@ -638,7 +628,6 @@ static int rpmh_probe_tcs_config(struct platform_device *pdev,
 		tcs->type = tcs_cfg[i].type;
 		tcs->num_tcs = tcs_cfg[i].n;
 		tcs->ncpt = ncpt;
-		spin_lock_init(&tcs->lock);
 
 		if (!tcs->num_tcs || tcs->type == CONTROL_TCS)
 			continue;
diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
index 71a76ea..297d6cc 100644
--- a/drivers/soc/qcom/rpmh.c
+++ b/drivers/soc/qcom/rpmh.c
@@ -117,9 +117,8 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
 					   struct tcs_cmd *cmd)
 {
 	struct cache_req *req;
-	unsigned long flags;
 
-	spin_lock_irqsave(&ctrlr->cache_lock, flags);
+	spin_lock(&ctrlr->cache_lock);
 	req = __find_req(ctrlr, cmd->addr);
 	if (req)
 		goto existing;
@@ -153,7 +152,7 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
 
 	ctrlr->dirty = true;
 unlock:
-	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
+	spin_unlock(&ctrlr->cache_lock);
 
 	return req;
 }
@@ -283,23 +282,21 @@ int rpmh_write(const struct device *dev, enum rpmh_state state,
 
 static void cache_batch(struct rpmh_ctrlr *ctrlr, struct batch_cache_req *req)
 {
-	unsigned long flags;
 
-	spin_lock_irqsave(&ctrlr->cache_lock, flags);
+	spin_lock(&ctrlr->cache_lock);
 	list_add_tail(&req->list, &ctrlr->batch_cache);
-	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
+	spin_unlock(&ctrlr->cache_lock);
 }
 
 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);
+	spin_lock(&ctrlr->cache_lock);
 	list_for_each_entry(req, &ctrlr->batch_cache, list) {
 		for (i = 0; i < req->count; i++) {
 			rpm_msg = req->rpm_msgs + i;
@@ -309,7 +306,7 @@ static int flush_batch(struct rpmh_ctrlr *ctrlr)
 				break;
 		}
 	}
-	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
+	spin_unlock(&ctrlr->cache_lock);
 
 	return ret;
 }
@@ -317,13 +314,12 @@ static int flush_batch(struct rpmh_ctrlr *ctrlr)
 static void invalidate_batch(struct rpmh_ctrlr *ctrlr)
 {
 	struct batch_cache_req *req, *tmp;
-	unsigned long flags;
 
-	spin_lock_irqsave(&ctrlr->cache_lock, flags);
+	spin_lock(&ctrlr->cache_lock);
 	list_for_each_entry_safe(req, tmp, &ctrlr->batch_cache, list)
 		kfree(req);
 	INIT_LIST_HEAD(&ctrlr->batch_cache);
-	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
+	spin_unlock(&ctrlr->cache_lock);
 }
 
 /**
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of the Code Aurora Forum, hosted by The Linux Foundation.

[PATCH v3 2/3] drivers: qcom: rpmh-rsc: return if the controller is idle

[Raju P.L.S.S.S.N]

From: Lina Iyer <ilina@codeaurora.org>

Allow the controller status be queried. The controller is busy if it is
actively processing request. Also allow the controller state be read by
platform drivers. This is useful for PM drivers which can choose to
disallow idle modes when the controller is busy.

Signed-off-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Raju P.L.S.S.S.N <rplsssn@codeaurora.org>
---
changes in v3
- Add lock check to avoid potential race as suggested by Matthias
---
 drivers/soc/qcom/rpmh-internal.h |  1 +
 drivers/soc/qcom/rpmh-rsc.c      | 24 ++++++++++++++++++++++++
 drivers/soc/qcom/rpmh.c          | 13 +++++++++++++
 include/soc/qcom/rpmh.h          |  5 +++++
 4 files changed, 43 insertions(+)

diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h
index 2e3ffcd..4b891c23 100644
--- a/drivers/soc/qcom/rpmh-internal.h
+++ b/drivers/soc/qcom/rpmh-internal.h
@@ -109,6 +109,7 @@ int rpmh_rsc_write_ctrl_data(struct rsc_drv *drv,
 			     const struct tcs_request *msg);
 int rpmh_rsc_invalidate(struct rsc_drv *drv);
 int rpmh_rsc_write_pdc_data(struct rsc_drv *drv, const struct tcs_request *msg);
+bool rpmh_rsc_ctrlr_is_idle(struct rsc_drv *drv);
 void rpmh_tx_done(const struct tcs_request *msg, int r);
 
 #endif /* __RPM_INTERNAL_H__ */
diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index d6b834e..9cc303e 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -525,6 +525,30 @@ static int tcs_ctrl_write(struct rsc_drv *drv, const struct tcs_request *msg)
 }
 
 /**
+ *  rpmh_rsc_ctrlr_is_idle: Check if any of the AMCs are busy.
+ *
+ *  @drv: The controller
+ *
+ *  Returns true if the TCSes are engaged in handling requests.
+ */
+bool rpmh_rsc_ctrlr_is_idle(struct rsc_drv *drv)
+{
+	int m;
+	struct tcs_group *tcs = get_tcs_of_type(drv, ACTIVE_TCS);
+
+	spin_lock(&drv->lock);
+	for (m = tcs->offset; m < tcs->offset + tcs->num_tcs; m++) {
+		if (!tcs_is_free(drv, m)) {
+			spin_unlock(&drv->lock);
+			return false;
+		}
+	}
+	spin_unlock(&drv->lock);
+
+	return true;
+}
+
+/**
  * rpmh_rsc_write_ctrl_data: Write request to the controller
  *
  * @drv: the controller
diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
index 297d6cc..43eb981 100644
--- a/drivers/soc/qcom/rpmh.c
+++ b/drivers/soc/qcom/rpmh.c
@@ -535,3 +535,16 @@ int rpmh_invalidate(const struct device *dev)
 	return ret;
 }
 EXPORT_SYMBOL(rpmh_invalidate);
+
+/**
+ * rpmh_ctrlr_idle: Return the controller idle status
+ *
+ * @dev: the device making the request
+ */
+int rpmh_ctrlr_idle(const struct device *dev)
+{
+	struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
+
+	return rpmh_rsc_ctrlr_is_idle(ctrlr_to_drv(ctrlr));
+}
+EXPORT_SYMBOL(rpmh_ctrlr_idle);
diff --git a/include/soc/qcom/rpmh.h b/include/soc/qcom/rpmh.h
index b05e31a..4c4b013 100644
--- a/include/soc/qcom/rpmh.h
+++ b/include/soc/qcom/rpmh.h
@@ -27,6 +27,8 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state,
 int rpmh_write_pdc_data(const struct device *dev,
 			const struct tcs_cmd *cmd, u32 n);
 
+int rpmh_ctrlr_idle(const struct device *dev);
+
 #else
 
 static inline int rpmh_write(const struct device *dev, enum rpmh_state state,
@@ -53,6 +55,9 @@ static inline int rpmh_write_pdc_data(const struct device *dev,
 				      const struct tcs_cmd *cmd, u32 n)
 { return -ENODEV; }
 
+static inline int rpmh_ctrlr_idle(const struct device *dev)
+{ return -ENODEV; }
+
 #endif /* CONFIG_QCOM_RPMH */
 
 #endif /* __SOC_QCOM_RPMH_H__ */
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of the Code Aurora Forum, hosted by The Linux Foundation.

[PATCH v3 3/3] drivers: qcom: rpmh: disallow active requests in solver mode

[Raju P.L.S.S.S.N]

From: Lina Iyer <ilina@codeaurora.org>

Controllers may be in 'solver' state, where they could be in autonomous
mode executing low power modes for their hardware and as such are not
available for sending active votes. Device driver may notify RPMH API
that the controller is in solver mode and when in such mode, disallow
requests from platform drivers for state change using the RSC.

Signed-off-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Raju P.L.S.S.S.N <rplsssn@codeaurora.org>
---
Chanages in v3
 - Add functionality to set solver mode for RSC controller
 - return -EINVAL if active requests are sent in solver mode
---
 drivers/soc/qcom/rpmh-internal.h |  5 ++++
 drivers/soc/qcom/rpmh-rsc.c      | 31 ++++++++++++++++++++++++
 drivers/soc/qcom/rpmh.c          | 51 ++++++++++++++++++++++++++++++++++++++++
 include/soc/qcom/rpmh.h          |  5 ++++
 4 files changed, 92 insertions(+)

diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h
index 4b891c23..0923c45 100644
--- a/drivers/soc/qcom/rpmh-internal.h
+++ b/drivers/soc/qcom/rpmh-internal.h
@@ -70,12 +70,14 @@ struct rpmh_request {
  * @cache_lock: synchronize access to the cache data
  * @dirty: was the cache updated since flush
  * @batch_cache: Cache sleep and wake requests sent as batch
+ * @in_solver_mode: Controller is busy in solver mode
  */
 struct rpmh_ctrlr {
 	struct list_head cache;
 	spinlock_t cache_lock;
 	bool dirty;
 	struct list_head batch_cache;
+	bool in_solver_mode;
 };
 
 /**
@@ -86,6 +88,7 @@ struct rpmh_ctrlr {
  * @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)
+ * @in_solver_mode: Controller is in solver mode
  * @num_tcs:    number of TCSes in this DRV
  * @tcs:        TCS groups
  * @tcs_in_use: s/w state of the TCS
@@ -97,6 +100,7 @@ struct rsc_drv {
 	void __iomem *base;
 	void __iomem *tcs_base;
 	int id;
+	bool in_solver_mode;
 	int num_tcs;
 	struct tcs_group tcs[TCS_TYPE_NR];
 	DECLARE_BITMAP(tcs_in_use, MAX_TCS_NR);
@@ -107,6 +111,7 @@ struct rsc_drv {
 int rpmh_rsc_send_data(struct rsc_drv *drv, const struct tcs_request *msg);
 int rpmh_rsc_write_ctrl_data(struct rsc_drv *drv,
 			     const struct tcs_request *msg);
+void rpmh_rsc_mode_solver_set(struct rsc_drv *drv, bool enable);
 int rpmh_rsc_invalidate(struct rsc_drv *drv);
 int rpmh_rsc_write_pdc_data(struct rsc_drv *drv, const struct tcs_request *msg);
 bool rpmh_rsc_ctrlr_is_idle(struct rsc_drv *drv);
diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index 9cc303e..17126be 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -386,6 +386,11 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
 		return PTR_ERR(tcs);
 
 	spin_lock(&drv->lock);
+
+	if (msg->state == RPMH_ACTIVE_ONLY_STATE && drv->in_solver_mode) {
+		ret = -EINVAL;
+		goto done_write;
+	}
 	/*
 	 * The h/w does not like if we send a request to the same address,
 	 * when one is already in-flight or being processed.
@@ -525,6 +530,31 @@ static int tcs_ctrl_write(struct rsc_drv *drv, const struct tcs_request *msg)
 }
 
 /**
+ *  rpmh_rsc_mode_solver_set: Enable/disable solver mode
+ *
+ *  @drv: The controller
+ *
+ *  enable: boolean state to be set - true/false
+ */
+void rpmh_rsc_mode_solver_set(struct rsc_drv *drv, bool enable)
+{
+	int m;
+	struct tcs_group *tcs = get_tcs_of_type(drv, ACTIVE_TCS);
+
+again:
+	spin_lock(&drv->lock);
+	for (m = tcs->offset; m < tcs->offset + tcs->num_tcs; m++) {
+		if (!tcs_is_free(drv, m)) {
+			spin_unlock(&drv->lock);
+			goto again;
+		}
+	}
+	drv->in_solver_mode = enable;
+	spin_unlock(&drv->lock);
+
+}
+
+/**
  *  rpmh_rsc_ctrlr_is_idle: Check if any of the AMCs are busy.
  *
  *  @drv: The controller
@@ -718,6 +748,7 @@ static int rpmh_rsc_probe(struct platform_device *pdev)
 		return ret;
 
 	spin_lock_init(&drv->lock);
+	drv->in_solver_mode = false;
 	bitmap_zero(drv->tcs_in_use, MAX_TCS_NR);
 
 	irq = platform_get_irq(pdev, drv->id);
diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
index 43eb981..e6e98d4 100644
--- a/drivers/soc/qcom/rpmh.c
+++ b/drivers/soc/qcom/rpmh.c
@@ -5,6 +5,7 @@
 
 #include <linux/atomic.h>
 #include <linux/bug.h>
+#include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
@@ -75,6 +76,42 @@ static struct rpmh_ctrlr *get_rpmh_ctrlr(const struct device *dev)
 	return &drv->client;
 }
 
+static int check_ctrlr_state(struct rpmh_ctrlr *ctrlr, enum rpmh_state state)
+{
+	int ret = 0;
+
+	/* Do not allow setting active votes when in solver mode */
+	spin_lock(&ctrlr->cache_lock);
+	if (ctrlr->in_solver_mode && state == RPMH_ACTIVE_ONLY_STATE)
+		ret = -EBUSY;
+	spin_unlock(&ctrlr->cache_lock);
+
+	return ret;
+}
+
+/**
+ * rpmh_mode_solver_set: Indicate that the RSC controller hardware has
+ * been configured to be in solver mode
+ *
+ * @dev: the device making the request
+ * @enable: Boolean value indicating if the controller is in solver mode.
+ *
+ * When solver mode is enabled, passthru API will not be able to send wake
+ * votes, just awake and active votes.
+ */
+int rpmh_mode_solver_set(const struct device *dev, bool enable)
+{
+	struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
+
+	spin_lock(&ctrlr->cache_lock);
+	rpmh_rsc_mode_solver_set(ctrlr_to_drv(ctrlr), enable);
+	ctrlr->in_solver_mode = enable;
+	spin_unlock(&ctrlr->cache_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(rpmh_mode_solver_set);
+
 void rpmh_tx_done(const struct tcs_request *msg, int r)
 {
 	struct rpmh_request *rpm_msg = container_of(msg, struct rpmh_request,
@@ -230,8 +267,13 @@ int rpmh_write_async(const struct device *dev, enum rpmh_state state,
 		     const struct tcs_cmd *cmd, u32 n)
 {
 	struct rpmh_request *rpm_msg;
+	struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
 	int ret;
 
+	ret = check_ctrlr_state(ctrlr, state);
+	if (ret)
+		return ret;
+
 	rpm_msg = kzalloc(sizeof(*rpm_msg), GFP_ATOMIC);
 	if (!rpm_msg)
 		return -ENOMEM;
@@ -262,11 +304,16 @@ int rpmh_write(const struct device *dev, enum rpmh_state state,
 {
 	DECLARE_COMPLETION_ONSTACK(compl);
 	DEFINE_RPMH_MSG_ONSTACK(dev, state, &compl, rpm_msg);
+	struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
 	int ret;
 
 	if (!cmd || !n || n > MAX_RPMH_PAYLOAD)
 		return -EINVAL;
 
+	ret = check_ctrlr_state(ctrlr, state);
+	if (ret)
+		return ret;
+
 	memcpy(rpm_msg.cmd, cmd, n * sizeof(*cmd));
 	rpm_msg.msg.num_cmds = n;
 
@@ -353,6 +400,10 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state,
 	if (!cmd || !n)
 		return -EINVAL;
 
+	ret = check_ctrlr_state(ctrlr, state);
+	if (ret)
+		return ret;
+
 	while (n[count] > 0)
 		count++;
 	if (!count)
diff --git a/include/soc/qcom/rpmh.h b/include/soc/qcom/rpmh.h
index 4c4b013..e8356b6 100644
--- a/include/soc/qcom/rpmh.h
+++ b/include/soc/qcom/rpmh.h
@@ -29,6 +29,8 @@ int rpmh_write_pdc_data(const struct device *dev,
 
 int rpmh_ctrlr_idle(const struct device *dev);
 
+int rpmh_mode_solver_set(const struct device *dev, bool enable);
+
 #else
 
 static inline int rpmh_write(const struct device *dev, enum rpmh_state state,
@@ -58,6 +60,9 @@ static inline int rpmh_write_pdc_data(const struct device *dev,
 static inline int rpmh_ctrlr_idle(const struct device *dev)
 { return -ENODEV; }
 
+static inline int rpmh_mode_solver_set(const struct device *dev, bool enable)
+{ return -ENODEV; }
+
 #endif /* CONFIG_QCOM_RPMH */
 
 #endif /* __SOC_QCOM_RPMH_H__ */
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of the Code Aurora Forum, hosted by The Linux Foundation.

Re: [PATCH v3 1/3] drivers: qcom: rpmh-rsc: simplify TCS locking

[Lina Iyer]

On Tue, Oct 09 2018 at 20:08 -0600, Raju P.L.S.S.S.N wrote:
>tcs->lock was introduced to serialize access with in TCS group. But
>even without tcs->lock, drv->lock is serving the same purpose. So
>use single drv->lock.
>
>Other optimizations include -
> - Remove locking around clear_bit() in IRQ handler. clear_bit() is
>   atomic.
> - Remove redundant read of TCS registers.
> - Use spin_lock instead of _irq variants as the locks are not held
>   in interrupt context
>
>Suggested-by: Lina Iyer <ilina@codeaurora.org>
>Signed-off-by: Raju P.L.S.S.S.N <rplsssn@codeaurora.org>
Reviewed-by: Lina Iyer <ilina@codeaurora.org>

>---
>This patch is based on https://lkml.org/lkml/2018/10/3/422
>---
> drivers/soc/qcom/rpmh-internal.h |  2 --
> drivers/soc/qcom/rpmh-rsc.c      | 37 +++++++++++++------------------------
> drivers/soc/qcom/rpmh.c          | 20 ++++++++------------
> 3 files changed, 21 insertions(+), 38 deletions(-)
>
>diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h
>index 8c316b4..2e3ffcd 100644
>--- a/drivers/soc/qcom/rpmh-internal.h
>+++ b/drivers/soc/qcom/rpmh-internal.h
>@@ -28,7 +28,6 @@
>  * @offset:    start of the TCS group relative to the TCSes in the RSC
>  * @num_tcs:   number of TCSes in this type
>  * @ncpt:      number of commands in each TCS
>- * @lock:      lock for synchronizing this TCS writes
>  * @req:       requests that are sent from the TCS
>  * @cmd_cache: flattened cache of cmds in sleep/wake TCS
>  * @slots:     indicates which of @cmd_addr are occupied
>@@ -40,7 +39,6 @@ struct tcs_group {
> 	u32 offset;
> 	int num_tcs;
> 	int ncpt;
>-	spinlock_t lock;
> 	const struct tcs_request *req[MAX_TCS_PER_TYPE];
> 	u32 *cmd_cache;
> 	DECLARE_BITMAP(slots, MAX_TCS_SLOTS);
>diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
>index 73d5b98..d6b834e 100644
>--- a/drivers/soc/qcom/rpmh-rsc.c
>+++ b/drivers/soc/qcom/rpmh-rsc.c
>@@ -98,8 +98,7 @@ static void write_tcs_reg_sync(struct rsc_drv *drv, int reg, int tcs_id,
>
> static bool tcs_is_free(struct rsc_drv *drv, int tcs_id)
> {
>-	return !test_bit(tcs_id, drv->tcs_in_use) &&
>-	       read_tcs_reg(drv, RSC_DRV_STATUS, tcs_id, 0);
>+	return !test_bit(tcs_id, drv->tcs_in_use);
> }
>
> static struct tcs_group *get_tcs_of_type(struct rsc_drv *drv, int type)
>@@ -109,29 +108,28 @@ static struct tcs_group *get_tcs_of_type(struct rsc_drv *drv, int type)
>
> static int tcs_invalidate(struct rsc_drv *drv, int type)
> {
>-	int m;
>+	int m, ret = 0;
> 	struct tcs_group *tcs;
>
> 	tcs = get_tcs_of_type(drv, type);
>
>-	spin_lock(&tcs->lock);
>-	if (bitmap_empty(tcs->slots, MAX_TCS_SLOTS)) {
>-		spin_unlock(&tcs->lock);
>-		return 0;
>-	}
>+	spin_lock(&drv->lock);
>+	if (bitmap_empty(tcs->slots, MAX_TCS_SLOTS))
>+		goto done;
>
> 	for (m = tcs->offset; m < tcs->offset + tcs->num_tcs; m++) {
> 		if (!tcs_is_free(drv, m)) {
>-			spin_unlock(&tcs->lock);
>-			return -EAGAIN;
>+			ret = -EAGAIN;
>+			goto done;
> 		}
> 		write_tcs_reg_sync(drv, RSC_DRV_CMD_ENABLE, m, 0);
> 		write_tcs_reg_sync(drv, RSC_DRV_CMD_WAIT_FOR_CMPL, m, 0);
> 	}
> 	bitmap_zero(tcs->slots, MAX_TCS_SLOTS);
>-	spin_unlock(&tcs->lock);
>
>-	return 0;
>+done:
>+	spin_unlock(&drv->lock);
>+	return ret;
> }
>
> /**
>@@ -298,9 +296,7 @@ static irqreturn_t tcs_tx_done(int irq, void *p)
> 		write_tcs_reg(drv, RSC_DRV_CMD_ENABLE, i, 0);
> 		write_tcs_reg(drv, RSC_DRV_CMD_WAIT_FOR_CMPL, i, 0);
> 		write_tcs_reg(drv, RSC_DRV_IRQ_CLEAR, 0, BIT(i));
>-		spin_lock(&drv->lock);
> 		clear_bit(i, drv->tcs_in_use);
>-		spin_unlock(&drv->lock);
> 		if (req)
> 			rpmh_tx_done(req, err);
> 	}
>@@ -383,14 +379,12 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
> {
> 	struct tcs_group *tcs;
> 	int tcs_id;
>-	unsigned long flags;
> 	int ret;
>
> 	tcs = get_tcs_for_msg(drv, msg);
> 	if (IS_ERR(tcs))
> 		return PTR_ERR(tcs);
>
>-	spin_lock_irqsave(&tcs->lock, flags);
> 	spin_lock(&drv->lock);
> 	/*
> 	 * The h/w does not like if we send a request to the same address,
>@@ -398,14 +392,12 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
> 	 */
> 	ret = check_for_req_inflight(drv, tcs, msg);
> 	if (ret) {
>-		spin_unlock(&drv->lock);
> 		goto done_write;
> 	}
>
> 	tcs_id = find_free_tcs(tcs);
> 	if (tcs_id < 0) {
> 		ret = tcs_id;
>-		spin_unlock(&drv->lock);
> 		goto done_write;
> 	}
>
>@@ -413,13 +405,12 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *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, true);
>
> done_write:
>-	spin_unlock_irqrestore(&tcs->lock, flags);
>+	spin_unlock(&drv->lock);
> 	return ret;
> }
>
>@@ -517,19 +508,18 @@ static int tcs_ctrl_write(struct rsc_drv *drv, const struct tcs_request *msg)
> {
> 	struct tcs_group *tcs;
> 	int tcs_id = 0, cmd_id = 0;
>-	unsigned long flags;
> 	int ret;
>
> 	tcs = get_tcs_for_msg(drv, msg);
> 	if (IS_ERR(tcs))
> 		return PTR_ERR(tcs);
>
>-	spin_lock_irqsave(&tcs->lock, flags);
>+	spin_lock(&drv->lock);
> 	/* find the TCS id and the command in the TCS to write to */
> 	ret = find_slots(tcs, msg, &tcs_id, &cmd_id);
> 	if (!ret)
> 		__tcs_buffer_write(drv, tcs_id, cmd_id, msg);
>-	spin_unlock_irqrestore(&tcs->lock, flags);
>+	spin_unlock(&drv->lock);
>
> 	return ret;
> }
>@@ -638,7 +628,6 @@ static int rpmh_probe_tcs_config(struct platform_device *pdev,
> 		tcs->type = tcs_cfg[i].type;
> 		tcs->num_tcs = tcs_cfg[i].n;
> 		tcs->ncpt = ncpt;
>-		spin_lock_init(&tcs->lock);
>
> 		if (!tcs->num_tcs || tcs->type == CONTROL_TCS)
> 			continue;
>diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
>index 71a76ea..297d6cc 100644
>--- a/drivers/soc/qcom/rpmh.c
>+++ b/drivers/soc/qcom/rpmh.c
>@@ -117,9 +117,8 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
> 					   struct tcs_cmd *cmd)
> {
> 	struct cache_req *req;
>-	unsigned long flags;
>
>-	spin_lock_irqsave(&ctrlr->cache_lock, flags);
>+	spin_lock(&ctrlr->cache_lock);
> 	req = __find_req(ctrlr, cmd->addr);
> 	if (req)
> 		goto existing;
>@@ -153,7 +152,7 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
>
> 	ctrlr->dirty = true;
> unlock:
>-	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>+	spin_unlock(&ctrlr->cache_lock);
>
> 	return req;
> }
>@@ -283,23 +282,21 @@ int rpmh_write(const struct device *dev, enum rpmh_state state,
>
> static void cache_batch(struct rpmh_ctrlr *ctrlr, struct batch_cache_req *req)
> {
>-	unsigned long flags;
>
>-	spin_lock_irqsave(&ctrlr->cache_lock, flags);
>+	spin_lock(&ctrlr->cache_lock);
> 	list_add_tail(&req->list, &ctrlr->batch_cache);
>-	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>+	spin_unlock(&ctrlr->cache_lock);
> }
>
> 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);
>+	spin_lock(&ctrlr->cache_lock);
> 	list_for_each_entry(req, &ctrlr->batch_cache, list) {
> 		for (i = 0; i < req->count; i++) {
> 			rpm_msg = req->rpm_msgs + i;
>@@ -309,7 +306,7 @@ static int flush_batch(struct rpmh_ctrlr *ctrlr)
> 				break;
> 		}
> 	}
>-	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>+	spin_unlock(&ctrlr->cache_lock);
>
> 	return ret;
> }
>@@ -317,13 +314,12 @@ static int flush_batch(struct rpmh_ctrlr *ctrlr)
> static void invalidate_batch(struct rpmh_ctrlr *ctrlr)
> {
> 	struct batch_cache_req *req, *tmp;
>-	unsigned long flags;
>
>-	spin_lock_irqsave(&ctrlr->cache_lock, flags);
>+	spin_lock(&ctrlr->cache_lock);
> 	list_for_each_entry_safe(req, tmp, &ctrlr->batch_cache, list)
> 		kfree(req);
> 	INIT_LIST_HEAD(&ctrlr->batch_cache);
>-	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>+	spin_unlock(&ctrlr->cache_lock);
> }
>
> /**
>--
>QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
>of the Code Aurora Forum, hosted by The Linux Foundation.
>

Re: [PATCH v3 3/3] drivers: qcom: rpmh: disallow active requests in solver mode

[Evan Green]

On Mon, Oct 8, 2018 at 7:09 PM Raju P.L.S.S.S.N <rplsssn@codeaurora.org> wrote:
>
> From: Lina Iyer <ilina@codeaurora.org>
>
> Controllers may be in 'solver' state, where they could be in autonomous
> mode executing low power modes for their hardware and as such are not
> available for sending active votes. Device driver may notify RPMH API
> that the controller is in solver mode and when in such mode, disallow
> requests from platform drivers for state change using the RSC.

Maybe I'm being dense, but I don't really get it. So in solver mode,
the whole RSC is just disabled? Solver mode just figures out what
state to put the hardware in without needing all these votes? Sounds
cool, why doesn't it just do that all the time? Can you describe an
example usecase of a real client that would use solver mode, and how
that works?

>
> Signed-off-by: Lina Iyer <ilina@codeaurora.org>
> Signed-off-by: Raju P.L.S.S.S.N <rplsssn@codeaurora.org>
> ---
> Chanages in v3
>  - Add functionality to set solver mode for RSC controller
>  - return -EINVAL if active requests are sent in solver mode
> ---
>  drivers/soc/qcom/rpmh-internal.h |  5 ++++
>  drivers/soc/qcom/rpmh-rsc.c      | 31 ++++++++++++++++++++++++
>  drivers/soc/qcom/rpmh.c          | 51 ++++++++++++++++++++++++++++++++++++++++
>  include/soc/qcom/rpmh.h          |  5 ++++
>  4 files changed, 92 insertions(+)
>
> diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h
> index 4b891c23..0923c45 100644
> --- a/drivers/soc/qcom/rpmh-internal.h
> +++ b/drivers/soc/qcom/rpmh-internal.h
> @@ -70,12 +70,14 @@ struct rpmh_request {
>   * @cache_lock: synchronize access to the cache data
>   * @dirty: was the cache updated since flush
>   * @batch_cache: Cache sleep and wake requests sent as batch
> + * @in_solver_mode: Controller is busy in solver mode
>   */
>  struct rpmh_ctrlr {
>         struct list_head cache;
>         spinlock_t cache_lock;
>         bool dirty;
>         struct list_head batch_cache;
> +       bool in_solver_mode;
>  };
>
>  /**
> @@ -86,6 +88,7 @@ struct rpmh_ctrlr {
>   * @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)
> + * @in_solver_mode: Controller is in solver mode
>   * @num_tcs:    number of TCSes in this DRV
>   * @tcs:        TCS groups
>   * @tcs_in_use: s/w state of the TCS
> @@ -97,6 +100,7 @@ struct rsc_drv {
>         void __iomem *base;
>         void __iomem *tcs_base;
>         int id;
> +       bool in_solver_mode;
>         int num_tcs;
>         struct tcs_group tcs[TCS_TYPE_NR];
>         DECLARE_BITMAP(tcs_in_use, MAX_TCS_NR);
> @@ -107,6 +111,7 @@ struct rsc_drv {
>  int rpmh_rsc_send_data(struct rsc_drv *drv, const struct tcs_request *msg);
>  int rpmh_rsc_write_ctrl_data(struct rsc_drv *drv,
>                              const struct tcs_request *msg);
> +void rpmh_rsc_mode_solver_set(struct rsc_drv *drv, bool enable);
>  int rpmh_rsc_invalidate(struct rsc_drv *drv);
>  int rpmh_rsc_write_pdc_data(struct rsc_drv *drv, const struct tcs_request *msg);
>  bool rpmh_rsc_ctrlr_is_idle(struct rsc_drv *drv);
> diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
> index 9cc303e..17126be 100644
> --- a/drivers/soc/qcom/rpmh-rsc.c
> +++ b/drivers/soc/qcom/rpmh-rsc.c
> @@ -386,6 +386,11 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
>                 return PTR_ERR(tcs);
>
>         spin_lock(&drv->lock);
> +
> +       if (msg->state == RPMH_ACTIVE_ONLY_STATE && drv->in_solver_mode) {
> +               ret = -EINVAL;
> +               goto done_write;
> +       }
>         /*
>          * The h/w does not like if we send a request to the same address,
>          * when one is already in-flight or being processed.
> @@ -525,6 +530,31 @@ static int tcs_ctrl_write(struct rsc_drv *drv, const struct tcs_request *msg)
>  }
>
>  /**
> + *  rpmh_rsc_mode_solver_set: Enable/disable solver mode
> + *
> + *  @drv: The controller
> + *
> + *  enable: boolean state to be set - true/false

Add an @?

> + */
> +void rpmh_rsc_mode_solver_set(struct rsc_drv *drv, bool enable)
> +{
> +       int m;
> +       struct tcs_group *tcs = get_tcs_of_type(drv, ACTIVE_TCS);
> +
> +again:
> +       spin_lock(&drv->lock);
> +       for (m = tcs->offset; m < tcs->offset + tcs->num_tcs; m++) {
> +               if (!tcs_is_free(drv, m)) {
> +                       spin_unlock(&drv->lock);
> +                       goto again;
> +               }
> +       }
> +       drv->in_solver_mode = enable;
> +       spin_unlock(&drv->lock);

I don't see you actually telling the controller to be in solver mode.
So I guess this is more informing the rpmh driver that something has
happened behind its back? Maybe the example will help me understand
this.

> +
> +}
> +
> +/**
>   *  rpmh_rsc_ctrlr_is_idle: Check if any of the AMCs are busy.
>   *
>   *  @drv: The controller
> @@ -718,6 +748,7 @@ static int rpmh_rsc_probe(struct platform_device *pdev)
>                 return ret;
>
>         spin_lock_init(&drv->lock);
> +       drv->in_solver_mode = false;
>         bitmap_zero(drv->tcs_in_use, MAX_TCS_NR);
>
>         irq = platform_get_irq(pdev, drv->id);
> diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
> index 43eb981..e6e98d4 100644
> --- a/drivers/soc/qcom/rpmh.c
> +++ b/drivers/soc/qcom/rpmh.c
> @@ -5,6 +5,7 @@
>
>  #include <linux/atomic.h>
>  #include <linux/bug.h>
> +#include <linux/delay.h>
>  #include <linux/interrupt.h>
>  #include <linux/jiffies.h>
>  #include <linux/kernel.h>
> @@ -75,6 +76,42 @@ static struct rpmh_ctrlr *get_rpmh_ctrlr(const struct device *dev)
>         return &drv->client;
>  }
>
> +static int check_ctrlr_state(struct rpmh_ctrlr *ctrlr, enum rpmh_state state)
> +{
> +       int ret = 0;
> +
> +       /* Do not allow setting active votes when in solver mode */
> +       spin_lock(&ctrlr->cache_lock);
> +       if (ctrlr->in_solver_mode && state == RPMH_ACTIVE_ONLY_STATE)
> +               ret = -EBUSY;
> +       spin_unlock(&ctrlr->cache_lock);
> +
> +       return ret;
> +}
> +
> +/**
> + * rpmh_mode_solver_set: Indicate that the RSC controller hardware has
> + * been configured to be in solver mode
> + *
> + * @dev: the device making the request
> + * @enable: Boolean value indicating if the controller is in solver mode.
> + *
> + * When solver mode is enabled, passthru API will not be able to send wake
> + * votes, just awake and active votes.

I don't understand this comment, maybe sharpening up the terminology
will help me?

> + */
> +int rpmh_mode_solver_set(const struct device *dev, bool enable)
> +{
> +       struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
> +
> +       spin_lock(&ctrlr->cache_lock);
> +       rpmh_rsc_mode_solver_set(ctrlr_to_drv(ctrlr), enable);
> +       ctrlr->in_solver_mode = enable;
> +       spin_unlock(&ctrlr->cache_lock);
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL(rpmh_mode_solver_set);
> +
>  void rpmh_tx_done(const struct tcs_request *msg, int r)
>  {
>         struct rpmh_request *rpm_msg = container_of(msg, struct rpmh_request,
> @@ -230,8 +267,13 @@ int rpmh_write_async(const struct device *dev, enum rpmh_state state,
>                      const struct tcs_cmd *cmd, u32 n)
>  {
>         struct rpmh_request *rpm_msg;
> +       struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
>         int ret;
>
> +       ret = check_ctrlr_state(ctrlr, state);
> +       if (ret)
> +               return ret;
> +
>         rpm_msg = kzalloc(sizeof(*rpm_msg), GFP_ATOMIC);
>         if (!rpm_msg)
>                 return -ENOMEM;
> @@ -262,11 +304,16 @@ int rpmh_write(const struct device *dev, enum rpmh_state state,
>  {
>         DECLARE_COMPLETION_ONSTACK(compl);
>         DEFINE_RPMH_MSG_ONSTACK(dev, state, &compl, rpm_msg);
> +       struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
>         int ret;
>
>         if (!cmd || !n || n > MAX_RPMH_PAYLOAD)
>                 return -EINVAL;
>
> +       ret = check_ctrlr_state(ctrlr, state);
> +       if (ret)
> +               return ret;
> +
>         memcpy(rpm_msg.cmd, cmd, n * sizeof(*cmd));
>         rpm_msg.msg.num_cmds = n;
>
> @@ -353,6 +400,10 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state,
>         if (!cmd || !n)
>                 return -EINVAL;
>
> +       ret = check_ctrlr_state(ctrlr, state);
> +       if (ret)
> +               return ret;
> +
>         while (n[count] > 0)
>                 count++;
>         if (!count)
> diff --git a/include/soc/qcom/rpmh.h b/include/soc/qcom/rpmh.h
> index 4c4b013..e8356b6 100644
> --- a/include/soc/qcom/rpmh.h
> +++ b/include/soc/qcom/rpmh.h
> @@ -29,6 +29,8 @@ int rpmh_write_pdc_data(const struct device *dev,
>
>  int rpmh_ctrlr_idle(const struct device *dev);
>
> +int rpmh_mode_solver_set(const struct device *dev, bool enable);
> +
>  #else
>
>  static inline int rpmh_write(const struct device *dev, enum rpmh_state state,
> @@ -58,6 +60,9 @@ static inline int rpmh_write_pdc_data(const struct device *dev,
>  static inline int rpmh_ctrlr_idle(const struct device *dev)
>  { return -ENODEV; }
>
> +static inline int rpmh_mode_solver_set(const struct device *dev, bool enable)
> +{ return -ENODEV; }
> +
>  #endif /* CONFIG_QCOM_RPMH */
>
>  #endif /* __SOC_QCOM_RPMH_H__ */
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of the Code Aurora Forum, hosted by The Linux Foundation.
>

Re: [PATCH v3 3/3] drivers: qcom: rpmh: disallow active requests in solver mode

[Lina Iyer]

On Wed, Oct 24 2018 at 11:43 -0600, Evan Green wrote:
>On Mon, Oct 8, 2018 at 7:09 PM Raju P.L.S.S.S.N <rplsssn@codeaurora.org> wrote:
>>
>> From: Lina Iyer <ilina@codeaurora.org>
>>
>> Controllers may be in 'solver' state, where they could be in autonomous
>> mode executing low power modes for their hardware and as such are not
>> available for sending active votes. Device driver may notify RPMH API
>> that the controller is in solver mode and when in such mode, disallow
>> requests from platform drivers for state change using the RSC.
>
>Maybe I'm being dense, but I don't really get it. So in solver mode,
>the whole RSC is just disabled? Solver mode just figures out what
>state to put the hardware in without needing all these votes? Sounds
>cool, why doesn't it just do that all the time? Can you describe an
>example usecase of a real client that would use solver mode, and how
>that works?
>
You are right. Solver just figures out the state to put the hardware in
for a short period of time. Usually when a usecase runs and the hw block
can periodically sleep while a partner/client is busy processing the
data, the solver can take care of figuring out the next wakeup and
choose the best low power mode for the hardware block and reduce the
votes. But all that have to be pre-programmed into the hardware. The
display RSC is a good example. A smart display controller can pick up
the data and show it on the screen and sleep until the next data needs
to be sent. The driver can configure the active and therefore the wake
values of the bus clocks and the sleep value, it can run without CPU
intervention. The display driver makes the decision to put the block in
solver mode and informs the RPMH block that the hardware is not to be
used for active requests or writing any sleep/wake votes.

Coordinating that with the drivers is a major pain point involving
multiple drivers. To avoid that, we let the RPMH know that the RSC is
running in solver mode and will ignore voting that may happen from
drivers.

Thanks,
Lina

>>
>> Signed-off-by: Lina Iyer <ilina@codeaurora.org>
>> Signed-off-by: Raju P.L.S.S.S.N <rplsssn@codeaurora.org>
>> ---
>> Chanages in v3
>>  - Add functionality to set solver mode for RSC controller
>>  - return -EINVAL if active requests are sent in solver mode
>> ---
>>  drivers/soc/qcom/rpmh-internal.h |  5 ++++
>>  drivers/soc/qcom/rpmh-rsc.c      | 31 ++++++++++++++++++++++++
>>  drivers/soc/qcom/rpmh.c          | 51 ++++++++++++++++++++++++++++++++++++++++
>>  include/soc/qcom/rpmh.h          |  5 ++++
>>  4 files changed, 92 insertions(+)
>>
>> diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h
>> index 4b891c23..0923c45 100644
>> --- a/drivers/soc/qcom/rpmh-internal.h
>> +++ b/drivers/soc/qcom/rpmh-internal.h
>> @@ -70,12 +70,14 @@ struct rpmh_request {
>>   * @cache_lock: synchronize access to the cache data
>>   * @dirty: was the cache updated since flush
>>   * @batch_cache: Cache sleep and wake requests sent as batch
>> + * @in_solver_mode: Controller is busy in solver mode
>>   */
>>  struct rpmh_ctrlr {
>>         struct list_head cache;
>>         spinlock_t cache_lock;
>>         bool dirty;
>>         struct list_head batch_cache;
>> +       bool in_solver_mode;
>>  };
>>
>>  /**
>> @@ -86,6 +88,7 @@ struct rpmh_ctrlr {
>>   * @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)
>> + * @in_solver_mode: Controller is in solver mode
>>   * @num_tcs:    number of TCSes in this DRV
>>   * @tcs:        TCS groups
>>   * @tcs_in_use: s/w state of the TCS
>> @@ -97,6 +100,7 @@ struct rsc_drv {
>>         void __iomem *base;
>>         void __iomem *tcs_base;
>>         int id;
>> +       bool in_solver_mode;
>>         int num_tcs;
>>         struct tcs_group tcs[TCS_TYPE_NR];
>>         DECLARE_BITMAP(tcs_in_use, MAX_TCS_NR);
>> @@ -107,6 +111,7 @@ struct rsc_drv {
>>  int rpmh_rsc_send_data(struct rsc_drv *drv, const struct tcs_request *msg);
>>  int rpmh_rsc_write_ctrl_data(struct rsc_drv *drv,
>>                              const struct tcs_request *msg);
>> +void rpmh_rsc_mode_solver_set(struct rsc_drv *drv, bool enable);
>>  int rpmh_rsc_invalidate(struct rsc_drv *drv);
>>  int rpmh_rsc_write_pdc_data(struct rsc_drv *drv, const struct tcs_request *msg);
>>  bool rpmh_rsc_ctrlr_is_idle(struct rsc_drv *drv);
>> diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
>> index 9cc303e..17126be 100644
>> --- a/drivers/soc/qcom/rpmh-rsc.c
>> +++ b/drivers/soc/qcom/rpmh-rsc.c
>> @@ -386,6 +386,11 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
>>                 return PTR_ERR(tcs);
>>
>>         spin_lock(&drv->lock);
>> +
>> +       if (msg->state == RPMH_ACTIVE_ONLY_STATE && drv->in_solver_mode) {
>> +               ret = -EINVAL;
>> +               goto done_write;
>> +       }
>>         /*
>>          * The h/w does not like if we send a request to the same address,
>>          * when one is already in-flight or being processed.
>> @@ -525,6 +530,31 @@ static int tcs_ctrl_write(struct rsc_drv *drv, const struct tcs_request *msg)
>>  }
>>
>>  /**
>> + *  rpmh_rsc_mode_solver_set: Enable/disable solver mode
>> + *
>> + *  @drv: The controller
>> + *
>> + *  enable: boolean state to be set - true/false
>
>Add an @?
>
>> + */
>> +void rpmh_rsc_mode_solver_set(struct rsc_drv *drv, bool enable)
>> +{
>> +       int m;
>> +       struct tcs_group *tcs = get_tcs_of_type(drv, ACTIVE_TCS);
>> +
>> +again:
>> +       spin_lock(&drv->lock);
>> +       for (m = tcs->offset; m < tcs->offset + tcs->num_tcs; m++) {
>> +               if (!tcs_is_free(drv, m)) {
>> +                       spin_unlock(&drv->lock);
>> +                       goto again;
>> +               }
>> +       }
>> +       drv->in_solver_mode = enable;
>> +       spin_unlock(&drv->lock);
>
>I don't see you actually telling the controller to be in solver mode.
>So I guess this is more informing the rpmh driver that something has
>happened behind its back? Maybe the example will help me understand
>this.
>
>> +
>> +}
>> +
>> +/**
>>   *  rpmh_rsc_ctrlr_is_idle: Check if any of the AMCs are busy.
>>   *
>>   *  @drv: The controller
>> @@ -718,6 +748,7 @@ static int rpmh_rsc_probe(struct platform_device *pdev)
>>                 return ret;
>>
>>         spin_lock_init(&drv->lock);
>> +       drv->in_solver_mode = false;
>>         bitmap_zero(drv->tcs_in_use, MAX_TCS_NR);
>>
>>         irq = platform_get_irq(pdev, drv->id);
>> diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
>> index 43eb981..e6e98d4 100644
>> --- a/drivers/soc/qcom/rpmh.c
>> +++ b/drivers/soc/qcom/rpmh.c
>> @@ -5,6 +5,7 @@
>>
>>  #include <linux/atomic.h>
>>  #include <linux/bug.h>
>> +#include <linux/delay.h>
>>  #include <linux/interrupt.h>
>>  #include <linux/jiffies.h>
>>  #include <linux/kernel.h>
>> @@ -75,6 +76,42 @@ static struct rpmh_ctrlr *get_rpmh_ctrlr(const struct device *dev)
>>         return &drv->client;
>>  }
>>
>> +static int check_ctrlr_state(struct rpmh_ctrlr *ctrlr, enum rpmh_state state)
>> +{
>> +       int ret = 0;
>> +
>> +       /* Do not allow setting active votes when in solver mode */
>> +       spin_lock(&ctrlr->cache_lock);
>> +       if (ctrlr->in_solver_mode && state == RPMH_ACTIVE_ONLY_STATE)
>> +               ret = -EBUSY;
>> +       spin_unlock(&ctrlr->cache_lock);
>> +
>> +       return ret;
>> +}
>> +
>> +/**
>> + * rpmh_mode_solver_set: Indicate that the RSC controller hardware has
>> + * been configured to be in solver mode
>> + *
>> + * @dev: the device making the request
>> + * @enable: Boolean value indicating if the controller is in solver mode.
>> + *
>> + * When solver mode is enabled, passthru API will not be able to send wake
>> + * votes, just awake and active votes.
>
>I don't understand this comment, maybe sharpening up the terminology
>will help me?
>
>> + */
>> +int rpmh_mode_solver_set(const struct device *dev, bool enable)
>> +{
>> +       struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
>> +
>> +       spin_lock(&ctrlr->cache_lock);
>> +       rpmh_rsc_mode_solver_set(ctrlr_to_drv(ctrlr), enable);
>> +       ctrlr->in_solver_mode = enable;
>> +       spin_unlock(&ctrlr->cache_lock);
>> +
>> +       return 0;
>> +}
>> +EXPORT_SYMBOL(rpmh_mode_solver_set);
>> +
>>  void rpmh_tx_done(const struct tcs_request *msg, int r)
>>  {
>>         struct rpmh_request *rpm_msg = container_of(msg, struct rpmh_request,
>> @@ -230,8 +267,13 @@ int rpmh_write_async(const struct device *dev, enum rpmh_state state,
>>                      const struct tcs_cmd *cmd, u32 n)
>>  {
>>         struct rpmh_request *rpm_msg;
>> +       struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
>>         int ret;
>>
>> +       ret = check_ctrlr_state(ctrlr, state);
>> +       if (ret)
>> +               return ret;
>> +
>>         rpm_msg = kzalloc(sizeof(*rpm_msg), GFP_ATOMIC);
>>         if (!rpm_msg)
>>                 return -ENOMEM;
>> @@ -262,11 +304,16 @@ int rpmh_write(const struct device *dev, enum rpmh_state state,
>>  {
>>         DECLARE_COMPLETION_ONSTACK(compl);
>>         DEFINE_RPMH_MSG_ONSTACK(dev, state, &compl, rpm_msg);
>> +       struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev);
>>         int ret;
>>
>>         if (!cmd || !n || n > MAX_RPMH_PAYLOAD)
>>                 return -EINVAL;
>>
>> +       ret = check_ctrlr_state(ctrlr, state);
>> +       if (ret)
>> +               return ret;
>> +
>>         memcpy(rpm_msg.cmd, cmd, n * sizeof(*cmd));
>>         rpm_msg.msg.num_cmds = n;
>>
>> @@ -353,6 +400,10 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state,
>>         if (!cmd || !n)
>>                 return -EINVAL;
>>
>> +       ret = check_ctrlr_state(ctrlr, state);
>> +       if (ret)
>> +               return ret;
>> +
>>         while (n[count] > 0)
>>                 count++;
>>         if (!count)
>> diff --git a/include/soc/qcom/rpmh.h b/include/soc/qcom/rpmh.h
>> index 4c4b013..e8356b6 100644
>> --- a/include/soc/qcom/rpmh.h
>> +++ b/include/soc/qcom/rpmh.h
>> @@ -29,6 +29,8 @@ int rpmh_write_pdc_data(const struct device *dev,
>>
>>  int rpmh_ctrlr_idle(const struct device *dev);
>>
>> +int rpmh_mode_solver_set(const struct device *dev, bool enable);
>> +
>>  #else
>>
>>  static inline int rpmh_write(const struct device *dev, enum rpmh_state state,
>> @@ -58,6 +60,9 @@ static inline int rpmh_write_pdc_data(const struct device *dev,
>>  static inline int rpmh_ctrlr_idle(const struct device *dev)
>>  { return -ENODEV; }
>>
>> +static inline int rpmh_mode_solver_set(const struct device *dev, bool enable)
>> +{ return -ENODEV; }
>> +
>>  #endif /* CONFIG_QCOM_RPMH */
>>
>>  #endif /* __SOC_QCOM_RPMH_H__ */
>> --
>> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
>> of the Code Aurora Forum, hosted by The Linux Foundation.
>>