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Message-ID: <20250401122545.1941755-2-cristian.marussi@arm.com>
Date: Tue, 1 Apr 2025 13:25:43 +0100
From: Cristian Marussi <cristian.marussi@....com>
To: linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
arm-scmi@...r.kernel.org
Cc: sudeep.holla@....com,
james.quinlan@...adcom.com,
f.fainelli@...il.com,
vincent.guittot@...aro.org,
peng.fan@....nxp.com,
michal.simek@....com,
quic_sibis@...cinc.com,
dan.carpenter@...aro.org,
maz@...nel.org,
johan@...nel.org,
stable@...r.kernel.org,
Johan Hovold <johan+linaro@...nel.org>,
Cristian Marussi <cristian.marussi@....com>
Subject: [RFC PATCH 1/3] firmware: arm_scmi: Ensure that the message-id supports fastchannel
From: Sibi Sankar <quic_sibis@...cinc.com>
Currently the perf and powercap protocol relies on the protocol domain
attributes, which just ensures that one fastchannel per domain, before
instantiating fastchannels for all possible message-ids. Fix this by
ensuring that each message-id supports fastchannel before initialization.
Logs:
scmi: Failed to get FC for protocol 13 [MSG_ID:6 / RES_ID:0] - ret:-95. Using regular messaging.
scmi: Failed to get FC for protocol 13 [MSG_ID:6 / RES_ID:1] - ret:-95. Using regular messaging.
scmi: Failed to get FC for protocol 13 [MSG_ID:6 / RES_ID:2] - ret:-95. Using regular messaging.
CC: stable@...r.kernel.org
Reported-by: Johan Hovold <johan+linaro@...nel.org>
Closes: https://lore.kernel.org/lkml/ZoQjAWse2YxwyRJv@hovoldconsulting.com/
Fixes: 6f9ea4dabd2d ("firmware: arm_scmi: Generalize the fast channel support")
Signed-off-by: Sibi Sankar <quic_sibis@...cinc.com>
[Cristian: Modified the condition checked to establish support or not]
Signed-off-by: Cristian Marussi <cristian.marussi@....com>
---
Since PROTOCOL_MESSAGE_ATTRIBUTES, used to check if message_id is supported,
is a mandatory command, it cannot fail so we must bail-out NOT only if FC was
not supported for that command but also if the query fails as a whole; so the
condition checked for bailing out is modified to:
if (ret || !MSG_SUPPORTS_FASTCHANNEL(attributes)) {
Removed also Tested-by and Reviewed-by tags since I modified the logic.
---
drivers/firmware/arm_scmi/driver.c | 76 +++++++++++++++------------
drivers/firmware/arm_scmi/protocols.h | 2 +
2 files changed, 45 insertions(+), 33 deletions(-)
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index bf2dc200604e..3855a9791f4a 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -1738,6 +1738,39 @@ static int scmi_common_get_max_msg_size(const struct scmi_protocol_handle *ph)
return info->desc->max_msg_size;
}
+/**
+ * scmi_protocol_msg_check - Check protocol message attributes
+ *
+ * @ph: A reference to the protocol handle.
+ * @message_id: The ID of the message to check.
+ * @attributes: A parameter to optionally return the retrieved message
+ * attributes, in case of Success.
+ *
+ * An helper to check protocol message attributes for a specific protocol
+ * and message pair.
+ *
+ * Return: 0 on SUCCESS
+ */
+static int scmi_protocol_msg_check(const struct scmi_protocol_handle *ph,
+ u32 message_id, u32 *attributes)
+{
+ int ret;
+ struct scmi_xfer *t;
+
+ ret = xfer_get_init(ph, PROTOCOL_MESSAGE_ATTRIBUTES,
+ sizeof(__le32), 0, &t);
+ if (ret)
+ return ret;
+
+ put_unaligned_le32(message_id, t->tx.buf);
+ ret = do_xfer(ph, t);
+ if (!ret && attributes)
+ *attributes = get_unaligned_le32(t->rx.buf);
+ xfer_put(ph, t);
+
+ return ret;
+}
+
/**
* struct scmi_iterator - Iterator descriptor
* @msg: A reference to the message TX buffer; filled by @prepare_message with
@@ -1879,6 +1912,7 @@ scmi_common_fastchannel_init(const struct scmi_protocol_handle *ph,
int ret;
u32 flags;
u64 phys_addr;
+ u32 attributes;
u8 size;
void __iomem *addr;
struct scmi_xfer *t;
@@ -1887,6 +1921,15 @@ scmi_common_fastchannel_init(const struct scmi_protocol_handle *ph,
struct scmi_msg_resp_desc_fc *resp;
const struct scmi_protocol_instance *pi = ph_to_pi(ph);
+ /* Check if the MSG_ID supports fastchannel */
+ ret = scmi_protocol_msg_check(ph, message_id, &attributes);
+ if (ret || !MSG_SUPPORTS_FASTCHANNEL(attributes)) {
+ dev_dbg(ph->dev,
+ "Skip FC init for 0x%02X/%d domain:%d - ret:%d\n",
+ pi->proto->id, message_id, domain, ret);
+ return;
+ }
+
if (!p_addr) {
ret = -EINVAL;
goto err_out;
@@ -2014,39 +2057,6 @@ static void scmi_common_fastchannel_db_ring(struct scmi_fc_db_info *db)
#endif
}
-/**
- * scmi_protocol_msg_check - Check protocol message attributes
- *
- * @ph: A reference to the protocol handle.
- * @message_id: The ID of the message to check.
- * @attributes: A parameter to optionally return the retrieved message
- * attributes, in case of Success.
- *
- * An helper to check protocol message attributes for a specific protocol
- * and message pair.
- *
- * Return: 0 on SUCCESS
- */
-static int scmi_protocol_msg_check(const struct scmi_protocol_handle *ph,
- u32 message_id, u32 *attributes)
-{
- int ret;
- struct scmi_xfer *t;
-
- ret = xfer_get_init(ph, PROTOCOL_MESSAGE_ATTRIBUTES,
- sizeof(__le32), 0, &t);
- if (ret)
- return ret;
-
- put_unaligned_le32(message_id, t->tx.buf);
- ret = do_xfer(ph, t);
- if (!ret && attributes)
- *attributes = get_unaligned_le32(t->rx.buf);
- xfer_put(ph, t);
-
- return ret;
-}
-
static const struct scmi_proto_helpers_ops helpers_ops = {
.extended_name_get = scmi_common_extended_name_get,
.get_max_msg_size = scmi_common_get_max_msg_size,
diff --git a/drivers/firmware/arm_scmi/protocols.h b/drivers/firmware/arm_scmi/protocols.h
index aaee57cdcd55..d62c4469d1fd 100644
--- a/drivers/firmware/arm_scmi/protocols.h
+++ b/drivers/firmware/arm_scmi/protocols.h
@@ -31,6 +31,8 @@
#define SCMI_PROTOCOL_VENDOR_BASE 0x80
+#define MSG_SUPPORTS_FASTCHANNEL(x) ((x) & BIT(0))
+
enum scmi_common_cmd {
PROTOCOL_VERSION = 0x0,
PROTOCOL_ATTRIBUTES = 0x1,
--
2.47.0
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