linux-kernel - [PATCH v2 11/18] firmware: arm_scmi: add option for polling based performance domain operations

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Date:   Fri,  4 Aug 2017 15:31:37 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     ALKML <linux-arm-kernel@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        DTML <devicetree@...r.kernel.org>
Cc:     Sudeep Holla <sudeep.holla@....com>,
        Roy Franz <roy.franz@...ium.com>,
        Harb Abdulhamid <harba@...eaurora.org>,
        Nishanth Menon <nm@...com>, Arnd Bergmann <arnd@...db.de>,
        Loc Ho <lho@....com>, Alexey Klimov <alexey.klimov@....com>,
        Ryan Harkin <Ryan.Harkin@....com>,
        Jassi Brar <jassisinghbrar@...il.com>
Subject: [PATCH v2 11/18] firmware: arm_scmi: add option for polling based performance domain operations

In order to implement fast CPU DVFS switching, we need to perform all
DVFS operations atomically. Since SCMI transfer already provide option
to choose between pooling vs interrupt driven(default), we can opt for
polling based transfers for set,get performance domain operations.

This patch adds option to choose between polling vs interrupt driven
SCMI transfers for set,get performance level operations.

Cc: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 drivers/firmware/arm_scmi/perf.c | 19 +++++++++++--------
 include/linux/scmi_protocol.h    |  8 ++++----
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
index 13d84d829201..334e8ec321ed 100644
--- a/drivers/firmware/arm_scmi/perf.c
+++ b/drivers/firmware/arm_scmi/perf.c
@@ -305,8 +305,8 @@ static int scmi_perf_limits_get(const struct scmi_handle *handle, u32 domain,
 	return ret;
 }
 
-static int
-scmi_perf_level_set(const struct scmi_handle *handle, u32 domain, u32 level)
+static int scmi_perf_level_set(const struct scmi_handle *handle, u32 domain,
+			       u32 level, bool poll)
 {
 	int ret;
 	struct scmi_xfer *t;
@@ -317,6 +317,7 @@ scmi_perf_level_set(const struct scmi_handle *handle, u32 domain, u32 level)
 	if (ret)
 		return ret;
 
+	t->hdr.poll_completion = poll;
 	lvl = t->tx.buf;
 	lvl->domain = cpu_to_le32(domain);
 	lvl->level = cpu_to_le32(level);
@@ -327,8 +328,8 @@ scmi_perf_level_set(const struct scmi_handle *handle, u32 domain, u32 level)
 	return ret;
 }
 
-static int
-scmi_perf_level_get(const struct scmi_handle *handle, u32 domain, u32 *level)
+static int scmi_perf_level_get(const struct scmi_handle *handle, u32 domain,
+			       u32 *level, bool poll)
 {
 	int ret;
 	struct scmi_xfer *t;
@@ -338,6 +339,7 @@ scmi_perf_level_get(const struct scmi_handle *handle, u32 domain, u32 *level)
 	if (ret)
 		return ret;
 
+	t->hdr.poll_completion = poll;
 	*(__le32 *)t->tx.buf = cpu_to_le32(domain);
 
 	ret = scmi_do_xfer(handle, t);
@@ -445,21 +447,22 @@ static int scmi_dvfs_get_transition_latency(struct device *dev)
 }
 
 static int scmi_dvfs_freq_set(const struct scmi_handle *handle, u32 domain,
-			      unsigned long freq)
+			      unsigned long freq, bool poll)
 {
 	struct perf_dom_info *dom = perf_info.dom_info + domain;
 
-	return scmi_perf_level_set(handle, domain, freq / dom->mult_factor);
+	return scmi_perf_level_set(handle, domain, freq / dom->mult_factor,
+				   poll);
 }
 
 static int scmi_dvfs_freq_get(const struct scmi_handle *handle, u32 domain,
-			      unsigned long *freq)
+			      unsigned long *freq, bool poll)
 {
 	int ret;
 	u32 level;
 	struct perf_dom_info *dom = perf_info.dom_info + domain;
 
-	ret = scmi_perf_level_get(handle, domain, &level);
+	ret = scmi_perf_level_get(handle, domain, &level, poll);
 	if (!ret)
 		*freq = level * dom->mult_factor;
 
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index d2a34cc9df8b..cf48fc3e2243 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -99,15 +99,15 @@ struct scmi_clk_ops {
 struct scmi_perf_ops {
 	int (*limits_set)(const struct scmi_handle *, u32, u32, u32);
 	int (*limits_get)(const struct scmi_handle *, u32, u32 *, u32 *);
-	int (*level_set)(const struct scmi_handle *, u32, u32);
-	int (*level_get)(const struct scmi_handle *, u32, u32 *);
+	int (*level_set)(const struct scmi_handle *, u32, u32, bool);
+	int (*level_get)(const struct scmi_handle *, u32, u32 *, bool);
 	int (*limits_notify_enable)(const struct scmi_handle *, u32, bool);
 	int (*level_notify_enable)(const struct scmi_handle *, u32, bool);
 	int (*device_domain_id)(struct device *);
 	int (*get_transition_latency)(struct device *);
 	int (*add_opps_to_device)(struct device *);
-	int (*freq_set)(const struct scmi_handle *, u32, unsigned long);
-	int (*freq_get)(const struct scmi_handle *, u32, unsigned long *);
+	int (*freq_set)(const struct scmi_handle *, u32, unsigned long, bool);
+	int (*freq_get)(const struct scmi_handle *, u32, unsigned long *, bool);
 };
 
 /**
-- 
2.7.4