[PATCH 1/2 v2] powerpc/dma: Define map/unmap mmio resource callbacks

[Max Gurtovoy <maxg@mellanox.com>]

Define the map_resource/unmap_resource callbacks for the dma_iommu_ops
used by several powerpc platforms. The map_resource callback is called
when trying to map a mmio resource through the dma_map_resource()
driver API.

For now, the callback returns an invalid address for devices using
translations, but will "direct" map the resource when in bypass
mode. Previous behavior for dma_map_resource() was to always return an
invalid address.

We also call an optional platform-specific controller op in
case some setup is needed for the platform.

Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
---

changes from v1:
 - rename pci_controller_ops callback to dma_direct_map_resource/dma_direct_unmap_resource
 - cosmetic changes to make the code more readable

---
 arch/powerpc/include/asm/pci-bridge.h |  7 +++++++
 arch/powerpc/kernel/dma-iommu.c       | 31 +++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/arch/powerpc/include/asm/pci-bridge.h b/arch/powerpc/include/asm/pci-bridge.h
index 69f4cb3..aca3724 100644
--- a/arch/powerpc/include/asm/pci-bridge.h
+++ b/arch/powerpc/include/asm/pci-bridge.h
@@ -44,6 +44,13 @@ struct pci_controller_ops {
 #endif
 
 	void		(*shutdown)(struct pci_controller *hose);
+	int		(*dma_direct_map_resource)(struct pci_dev *pdev,
+						phys_addr_t phys_addr,
+						size_t size,
+						enum dma_data_direction dir);
+	void		(*dma_direct_unmap_resource)(struct pci_dev *pdev,
+						dma_addr_t addr, size_t size,
+						enum dma_data_direction dir);
 };
 
 /*
diff --git a/arch/powerpc/kernel/dma-iommu.c b/arch/powerpc/kernel/dma-iommu.c
index e486d1d..049d000 100644
--- a/arch/powerpc/kernel/dma-iommu.c
+++ b/arch/powerpc/kernel/dma-iommu.c
@@ -108,6 +108,35 @@ static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
 		dma_direct_unmap_sg(dev, sglist, nelems, direction, attrs);
 }
 
+static dma_addr_t dma_iommu_map_resource(struct device *dev,
+					 phys_addr_t phys_addr, size_t size,
+					 enum dma_data_direction dir,
+					 unsigned long attrs)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct pci_controller *phb = pci_bus_to_host(pdev->bus);
+	struct pci_controller_ops *ops = &phb->controller_ops;
+
+	if (!dma_iommu_map_bypass(dev, attrs) ||
+	    !ops->dma_direct_map_resource ||
+	    ops->dma_direct_map_resource(pdev, phys_addr, size, dir))
+		return DMA_MAPPING_ERROR;
+
+	return dma_direct_map_resource(dev, phys_addr, size, dir, attrs);
+}
+
+static void dma_iommu_unmap_resource(struct device *dev, dma_addr_t dma_handle,
+				     size_t size, enum dma_data_direction dir,
+				     unsigned long attrs)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct pci_controller *phb = pci_bus_to_host(pdev->bus);
+	struct pci_controller_ops *ops = &phb->controller_ops;
+
+	if (dma_iommu_map_bypass(dev, attrs) && ops->dma_direct_unmap_resource)
+		ops->dma_direct_unmap_resource(pdev, dma_handle, size, dir);
+}
+
 static bool dma_iommu_bypass_supported(struct device *dev, u64 mask)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
@@ -199,6 +228,8 @@ extern void dma_iommu_sync_sg_for_device(struct device *dev,
 	.free			= dma_iommu_free_coherent,
 	.map_sg			= dma_iommu_map_sg,
 	.unmap_sg		= dma_iommu_unmap_sg,
+	.map_resource		= dma_iommu_map_resource,
+	.unmap_resource		= dma_iommu_unmap_resource,
 	.dma_supported		= dma_iommu_dma_supported,
 	.map_page		= dma_iommu_map_page,
 	.unmap_page		= dma_iommu_unmap_page,
-- 
1.8.3.1