Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Jonathan Marek <jonathan@marek.ca>
To:     freedreno@lists.freedesktop.org, hch@lst.de
Cc:     Marek Szyprowski <m.szyprowski@samsung.com>,
        Robin Murphy <robin.murphy@arm.com>,
        iommu@lists.linux-foundation.org (open list:DMA MAPPING HELPERS),
        linux-kernel@vger.kernel.org (open list)
Subject: [RESEND PATCH v2 2/5] dma-direct: add dma_direct_bypass() to force direct ops
Date:   Sat, 14 Nov 2020 10:17:10 -0500
Message-Id: <20201114151717.5369-3-jonathan@marek.ca>
In-Reply-To: <20201114151717.5369-1-jonathan@marek.ca>
References: <20201114151717.5369-1-jonathan@marek.ca>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Add a function to force direct ops and disable swiotlb for a deivce.

Signed-off-by: Jonathan Marek <jonathan@marek.ca>
---
 include/linux/dma-direct.h |  9 +++++++++
 kernel/dma/direct.c        | 23 +++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index 18aade195884..41f57e1b7aa5 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -124,4 +124,13 @@ int dma_direct_supported(struct device *dev, u64 mask);
 dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
 		size_t size, enum dma_data_direction dir, unsigned long attrs);
 
+#if IS_ENABLED(CONFIG_DMA_OPS_BYPASS) && !IS_ENABLED(CONFIG_ARCH_HAS_FORCE_DMA_UNENCRYPTED)
+int dma_direct_bypass(struct device *dev);
+#else
+static inline int dma_direct_bypass(struct device *dev)
+{
+	return -EIO;
+}
+#endif
+
 #endif /* _LINUX_DMA_DIRECT_H */
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 06c111544f61..304a5a77cccb 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -548,3 +548,26 @@ int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(dma_direct_set_offset);
+
+/**
+ * dma_direct_bypass - always use direct mapping path for device
+ * @dev:	device pointer
+ *
+ * Note: this also bypasses swiotlb. Not available for arch with
+ * force_dma_unencrypted(), since this doesn't deal with that.
+ */
+#if IS_ENABLED(CONFIG_DMA_OPS_BYPASS) && !IS_ENABLED(CONFIG_ARCH_HAS_FORCE_DMA_UNENCRYPTED)
+int dma_direct_bypass(struct device *dev)
+{
+	int ret;
+
+	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
+	if (ret)
+		return ret;
+
+	dev->bus_dma_limit = DMA_BIT_MASK(64);
+	dev->dma_ops_bypass = true;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dma_direct_bypass);
+#endif
-- 
2.26.1