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From:   Sudeep Holla <sudeep.holla@arm.com>
To:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc:     Sudeep Holla <sudeep.holla@arm.com>, quic_mdtipton@quicinc.com,
        quic_asartor@quicinc.com, quic_lingutla@quicinc.com,
        Sibi Sankar <quic_sibis@quicinc.com>,
        linux-arm-msm@vger.kernel.org,
        Cristian Marussi <cristian.marussi@arm.com>
Subject: [PATCH 1/2] firmware: arm_scmi: Fix frequency truncation by promoting multiplier to u64
Date:   Thu, 30 Nov 2023 20:43:42 +0000
Message-ID: <20231130204343.503076-1-sudeep.holla@arm.com>
MIME-Version: 1.0
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Precedence: bulk

Fix the frequency truncation for all values equal to or greater 4GHz by
updating the multiplier 'mult_factor' to u64 type. It is also possible
that the multiplier itself can be greater than or equal to 2^32. So we need
to also fix the equation computing the value of the multiplier.

Fixes: a9e3fbfaa0ff ("firmware: arm_scmi: add initial support for performance protocol")
Reported-by: Sibi Sankar <quic_sibis@quicinc.com>
Closes: https://lore.kernel.org/all/20231129065748.19871-3-quic_sibis@quicinc.com/
Cc: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 drivers/firmware/arm_scmi/perf.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
index 81dd5c5e5533..8ce449922e55 100644
--- a/drivers/firmware/arm_scmi/perf.c
+++ b/drivers/firmware/arm_scmi/perf.c
@@ -152,7 +152,7 @@ struct perf_dom_info {
 	u32 opp_count;
 	u32 sustained_freq_khz;
 	u32 sustained_perf_level;
-	u32 mult_factor;
+	u64 mult_factor;
 	struct scmi_perf_domain_info info;
 	struct scmi_opp opp[MAX_OPPS];
 	struct scmi_fc_info *fc_info;
@@ -273,8 +273,8 @@ scmi_perf_domain_attributes_get(const struct scmi_protocol_handle *ph,
 			dom_info->mult_factor =	1000;
 		else
 			dom_info->mult_factor =
-					(dom_info->sustained_freq_khz * 1000) /
-					dom_info->sustained_perf_level;
+					(dom_info->sustained_freq_khz * 1000UL)
+					/ dom_info->sustained_perf_level;
 		strscpy(dom_info->info.name, attr->name,
 			SCMI_SHORT_NAME_MAX_SIZE);
 	}
--
2.43.0