Feedback-ID: i51094778:Fastmail
From:   Sven Peter <sven@svenpeter.dev>
To:     Hector Martin <marcan@marcan.st>, Sven Peter <sven@svenpeter.dev>,
        Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Alyssa Rosenzweig <alyssa@rosenzweig.io>,
        linux-arm-kernel@lists.infradead.org, asahi@lists.linux.dev,
        iommu@lists.linux.dev, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 2/4] iommu: dart: Add flag to override bypass support
Date:   Sat, 28 Jan 2023 12:11:12 +0100
Message-Id: <20230128111114.4049-3-sven@svenpeter.dev>
In-Reply-To: <20230128111114.4049-1-sven@svenpeter.dev>
References: <20230128111114.4049-1-sven@svenpeter.dev>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The USB4 PCIe DARTs claim to support bypass but we never want to allow
that on externally facing ports.

Signed-off-by: Sven Peter <sven@svenpeter.dev>
---
 drivers/iommu/apple-dart.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
index 42666617803d..7d8b2b90cdb6 100644
--- a/drivers/iommu/apple-dart.c
+++ b/drivers/iommu/apple-dart.c
@@ -182,6 +182,8 @@ struct apple_dart_hw {
 	u64 ttbr_addr_field_shift;
 	u64 ttbr_shift;
 	int ttbr_count;
+
+	bool disable_bypass;
 };
 
 /*
@@ -1075,6 +1077,9 @@ static int apple_dart_probe(struct platform_device *pdev)
 	dart->pgsize = 1 << FIELD_GET(DART_PARAMS1_PAGE_SHIFT, dart_params[0]);
 	dart->supports_bypass = dart_params[1] & DART_PARAMS2_BYPASS_SUPPORT;
 
+	if (dart->hw->disable_bypass)
+		dart->supports_bypass = 0;
+
 	switch (dart->hw->type) {
 	case DART_T8020:
 	case DART_T6000:
-- 
2.25.1