linux-kernel - [PATCH] arm_mpam: Fix T241-MPAM-4 workaround

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Message-ID: <20240819220818.201870-1-sdonthineni@nvidia.com>
Date: Mon, 19 Aug 2024 17:08:18 -0500
From: Shanker Donthineni <sdonthineni@...dia.com>
To: James Morse <james.morse@....com>
CC: Catalin Marinas <catalin.marinas@....com>, Shanker Donthineni
	<sdonthineni@...dia.com>, Rohit Mathew <rohit.mathew@....com>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-doc@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, Vikram Sethi <vsethi@...dia.com>
Subject: [PATCH] arm_mpam: Fix T241-MPAM-4 workaround

The workaround for T241-MPAM-4 was applied incorrectly, leading to
MBW_MIN being programmed with a zero value when the user specifies
MBW_MAX is less than 5%.

This patch ensures that MBW_MIN is programmed with a non-zero value,
set to 1 to fix the T241-MPAM-4 as expected.

Fixes: 13ff1b527e40 ("arm_mpam: Add workaround for T241-MPAM-4")
Signed-off-by: Shanker Donthineni <sdonthineni@...dia.com>
---
 drivers/platform/arm64/mpam/mpam_devices.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/arm64/mpam/mpam_devices.c b/drivers/platform/arm64/mpam/mpam_devices.c
index a802ca1c9f05..e49a27c02c66 100644
--- a/drivers/platform/arm64/mpam/mpam_devices.c
+++ b/drivers/platform/arm64/mpam/mpam_devices.c
@@ -2990,7 +2990,7 @@ static void mpam_extend_config(struct mpam_class *class, struct mpam_config *cfg
 	}
 
 	if (mpam_has_quirk(T241_FORCE_MBW_MIN_TO_ONE, class) &&
-	    cfg->mbw_min == 0) {
+	    cfg->mbw_min <= min_hw_granule) {
 		cfg->mbw_min = min_hw_granule + 1;
 		mpam_set_feature(mpam_feat_mbw_min, cfg);
 	}
-- 
2.25.1