linux-kernel - [PATCH 22/22] firmware: arm_scmi: Add SCMIv3.1 PERFORMANCE_LIMITS

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Message-Id: <20220330150551.2573938-23-cristian.marussi@arm.com>
Date:   Wed, 30 Mar 2022 16:05:51 +0100
From:   Cristian Marussi <cristian.marussi@....com>
To:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc:     sudeep.holla@....com, james.quinlan@...adcom.com,
        Jonathan.Cameron@...wei.com, f.fainelli@...il.com,
        etienne.carriere@...aro.org, vincent.guittot@...aro.org,
        souvik.chakravarty@....com, cristian.marussi@....com
Subject: [PATCH 22/22] firmware: arm_scmi: Add SCMIv3.1 PERFORMANCE_LIMITS_SET checks

Starting with SCMIv3.1, the PERFORMANCE_LIMITS_SET command allows a user
to request only one between max and min ranges to be changed, while leaving
the other untouched if set to zero in the request; anyway SCMIv3.1 states
also explicitly that you cannot leave both of those unchanged (zeroed) when
issuing such command: add a proper check for this condition.

Signed-off-by: Cristian Marussi <cristian.marussi@....com>
---
 drivers/firmware/arm_scmi/perf.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
index 65ffda5495d6..8f4051aca220 100644
--- a/drivers/firmware/arm_scmi/perf.c
+++ b/drivers/firmware/arm_scmi/perf.c
@@ -423,6 +423,9 @@ static int scmi_perf_limits_set(const struct scmi_protocol_handle *ph,
 	struct scmi_perf_info *pi = ph->get_priv(ph);
 	struct perf_dom_info *dom = pi->dom_info + domain;
 
+	if (PROTOCOL_REV_MAJOR(pi->version) >= 0x3 && !max_perf && !min_perf)
+		return -EINVAL;
+
 	if (dom->fc_info && dom->fc_info->limit_set_addr) {
 		iowrite32(max_perf, dom->fc_info->limit_set_addr);
 		iowrite32(min_perf, dom->fc_info->limit_set_addr + 4);
-- 
2.32.0