[PATCH v2 09/10] firmware: arm_scmi: Drop config flag in clk_ops->rate_set

[PATCH v2 09/10] firmware: arm_scmi: Drop config flag in clk_ops->rate_set

[Sudeep Holla]

CLOCK_PROTOCOL_ATTRIBUTES provides attributes to indicate the maximum
number of pending asynchronous clock rate changes supported by the
platform. If it's non-zero, then we should be able to use asynchronous
clock rate set for any clocks until the maximum limit is reached.

In order to add that support, let's drop the config flag passed to
clk_ops->rate_set and handle the asynchronous requests dynamically.

Cc: Stephen Boyd <sboyd@kernel.org>
Cc: linux-clk@vger.kernel.org
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 drivers/clk/clk-scmi.c            | 2 +-
 drivers/firmware/arm_scmi/clock.c | 4 ++--
 include/linux/scmi_protocol.h     | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
index a2287c770d5c..886f7c5df51a 100644
--- a/drivers/clk/clk-scmi.c
+++ b/drivers/clk/clk-scmi.c
@@ -69,7 +69,7 @@ static int scmi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 {
 	struct scmi_clk *clk = to_scmi_clk(hw);
 
-	return clk->handle->clk_ops->rate_set(clk->handle, clk->id, 0, rate);
+	return clk->handle->clk_ops->rate_set(clk->handle, clk->id, rate);
 }
 
 static int scmi_clk_enable(struct clk_hw *hw)
diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c
index 0a194af92438..dd215bd11a58 100644
--- a/drivers/firmware/arm_scmi/clock.c
+++ b/drivers/firmware/arm_scmi/clock.c
@@ -218,7 +218,7 @@ scmi_clock_rate_get(const struct scmi_handle *handle, u32 clk_id, u64 *value)
 }
 
 static int scmi_clock_rate_set(const struct scmi_handle *handle, u32 clk_id,
-			       u32 config, u64 rate)
+			       u64 rate)
 {
 	int ret;
 	struct scmi_xfer *t;
@@ -230,7 +230,7 @@ static int scmi_clock_rate_set(const struct scmi_handle *handle, u32 clk_id,
 		return ret;
 
 	cfg = t->tx.buf;
-	cfg->flags = cpu_to_le32(config);
+	cfg->flags = cpu_to_le32(0);
 	cfg->id = cpu_to_le32(clk_id);
 	cfg->value_low = cpu_to_le32(rate & 0xffffffff);
 	cfg->value_high = cpu_to_le32(rate >> 32);
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index ae7381413f1f..f0f2b53a1dac 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -71,7 +71,7 @@ struct scmi_clk_ops {
 	int (*rate_get)(const struct scmi_handle *handle, u32 clk_id,
 			u64 *rate);
 	int (*rate_set)(const struct scmi_handle *handle, u32 clk_id,
-			u32 config, u64 rate);
+			u64 rate);
 	int (*enable)(const struct scmi_handle *handle, u32 clk_id);
 	int (*disable)(const struct scmi_handle *handle, u32 clk_id);
 };
-- 
2.17.1

[PATCH v2 10/10] firmware: arm_scmi: Use asynchronous CLOCK_RATE_SET when possible

[Sudeep Holla]

CLOCK_PROTOCOL_ATTRIBUTES provides attributes to indicate the maximum
number of pending asynchronous clock rate changes supported by the
platform. If it's non-zero, then we should be able to use asynchronous
clock rate set for any clocks until the maximum limit is reached.

Tracking the current count of pending asynchronous clock set rate
requests, we can decide if the incoming/new request for clock set rate
can be handled asynchronously or not until the maximum limit is
reached.

Cc: Stephen Boyd <sboyd@kernel.org>
Cc: linux-clk@vger.kernel.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 drivers/firmware/arm_scmi/clock.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c
index dd215bd11a58..4a32ae1822a3 100644
--- a/drivers/firmware/arm_scmi/clock.c
+++ b/drivers/firmware/arm_scmi/clock.c
@@ -56,7 +56,7 @@ struct scmi_msg_resp_clock_describe_rates {
 struct scmi_clock_set_rate {
 	__le32 flags;
 #define CLOCK_SET_ASYNC		BIT(0)
-#define CLOCK_SET_DELAYED	BIT(1)
+#define CLOCK_SET_IGNORE_RESP	BIT(1)
 #define CLOCK_SET_ROUND_UP	BIT(2)
 #define CLOCK_SET_ROUND_AUTO	BIT(3)
 	__le32 id;
@@ -67,6 +67,7 @@ struct scmi_clock_set_rate {
 struct clock_info {
 	int num_clocks;
 	int max_async_req;
+	atomic_t cur_async_req;
 	struct scmi_clock_info *clk;
 };
 
@@ -221,21 +222,33 @@ static int scmi_clock_rate_set(const struct scmi_handle *handle, u32 clk_id,
 			       u64 rate)
 {
 	int ret;
+	u32 flags = 0;
 	struct scmi_xfer *t;
 	struct scmi_clock_set_rate *cfg;
+	struct clock_info *ci = handle->clk_priv;
 
 	ret = scmi_xfer_get_init(handle, CLOCK_RATE_SET, SCMI_PROTOCOL_CLOCK,
 				 sizeof(*cfg), 0, &t);
 	if (ret)
 		return ret;
 
+	if (ci->max_async_req &&
+	    atomic_inc_return(&ci->cur_async_req) < ci->max_async_req)
+		flags |= CLOCK_SET_ASYNC;
+
 	cfg = t->tx.buf;
-	cfg->flags = cpu_to_le32(0);
+	cfg->flags = cpu_to_le32(flags);
 	cfg->id = cpu_to_le32(clk_id);
 	cfg->value_low = cpu_to_le32(rate & 0xffffffff);
 	cfg->value_high = cpu_to_le32(rate >> 32);
 
-	ret = scmi_do_xfer(handle, t);
+	if (flags & CLOCK_SET_ASYNC)
+		ret = scmi_do_xfer_with_response(handle, t);
+	else
+		ret = scmi_do_xfer(handle, t);
+
+	if (ci->max_async_req)
+		atomic_dec(&ci->cur_async_req);
 
 	scmi_xfer_put(handle, t);
 	return ret;
-- 
2.17.1

Re: [PATCH v2 10/10] firmware: arm_scmi: Use asynchronous CLOCK_RATE_SET when possible

[Stephen Boyd]

Quoting Sudeep Holla (2019-07-26 06:51:38)
> CLOCK_PROTOCOL_ATTRIBUTES provides attributes to indicate the maximum
> number of pending asynchronous clock rate changes supported by the
> platform. If it's non-zero, then we should be able to use asynchronous
> clock rate set for any clocks until the maximum limit is reached.
> 
> Tracking the current count of pending asynchronous clock set rate
> requests, we can decide if the incoming/new request for clock set rate
> can be handled asynchronously or not until the maximum limit is
> reached.
> 
> Cc: Stephen Boyd <sboyd@kernel.org>
> Cc: linux-clk@vger.kernel.org
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> ---

Reviewed-by: Stephen Boyd <sboyd@kernel.org>