[RFC PATCH v3 08/13] drivers: acpi: iort: add support for ARM SMMU platform devices creation

[Lorenzo Pieralisi]

In ARM ACPI systems, IOMMU components are specified through static
IORT table entries. In order to create platform devices for the
corresponding ARM SMMU components, IORT kernel code should be made
able to parse IORT table entries and create platform devices
dynamically.

This patch adds the generic IORT infrastructure required to create
platform devices for ARM SMMUs.

ARM SMMU versions have different resources requirement therefore this
patch also introduces an IORT specific structure (ie iort_iommu_config)
that contains hooks (to be defined when the corresponding ARM SMMU
driver support is added to the kernel) to be used to define the
platform devices names, init the IOMMUs, count their resources and
finally initialize them.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
Cc: Hanjun Guo <hanjun.guo at linaro.org>
Cc: Tomasz Nowicki <tn at semihalf.com>
Cc: "Rafael J. Wysocki" <rjw at rjwysocki.net>
---
 drivers/acpi/iort.c  | 107 +++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/iort.h |  10 +++++
 2 files changed, 117 insertions(+)

diff --git a/drivers/acpi/iort.c b/drivers/acpi/iort.c
index 71516e8..23c80c7 100644
--- a/drivers/acpi/iort.c
+++ b/drivers/acpi/iort.c
@@ -22,6 +22,7 @@
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/pci.h>
+#include <linux/platform_device.h>
 #include <linux/slab.h>
 
 struct iort_its_msi_chip {
@@ -454,6 +455,112 @@ iort_get_device_domain(struct device *dev, u32 req_id)
 	return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI);
 }
 
+struct iort_iommu_config {
+	const char *name;
+	int (*iommu_init)(struct acpi_iort_node *node);
+	bool (*iommu_is_coherent)(struct acpi_iort_node *node);
+	int (*iommu_count_resources)(struct acpi_iort_node *node);
+	void (*iommu_init_resources)(struct resource *res,
+				     struct acpi_iort_node *node);
+};
+
+static inline const struct iort_iommu_config *
+iort_get_iommu_config(struct acpi_iort_node *node)
+{
+	return NULL;
+}
+
+/**
+ * iort_add_smmu_platform_device() - Allocate a platform device for SMMU
+ * @fwnode: Pointer to SMMU firmware node
+ * @node: Pointer to SMMU ACPI IORT node
+ *
+ * Returns: 0 on success, <0 failure
+ */
+int iort_add_smmu_platform_device(struct fwnode_handle *fwnode,
+				  struct acpi_iort_node *node)
+{
+	struct platform_device *pdev;
+	struct resource *r;
+	enum dev_dma_attr attr;
+	int ret, count;
+	const struct iort_iommu_config *ops =
+				iort_get_iommu_config(node);
+
+	if (!ops)
+		return -ENODEV;
+
+	pdev = platform_device_alloc(ops->name, PLATFORM_DEVID_AUTO);
+	if (!pdev)
+		return PTR_ERR(pdev);
+
+	count = ops->iommu_count_resources(node);
+
+	r = kcalloc(count, sizeof(*r), GFP_KERNEL);
+	if (!r) {
+		ret = -ENOMEM;
+		goto dev_put;
+	}
+
+	ops->iommu_init_resources(r, node);
+
+	ret = platform_device_add_resources(pdev, r, count);
+	/*
+	 * Resources are duplicated in platform_device_add_resources,
+	 * free their allocated memory
+	 */
+	kfree(r);
+
+	if (ret)
+		goto dev_put;
+
+	/*
+	 * Add a copy of IORT node pointer to platform_data to
+	 * be used to retrieve IORT data information.
+	 */
+	ret = platform_device_add_data(pdev, &node, sizeof(node));
+	if (ret)
+		goto dev_put;
+
+	pdev->dev.dma_mask = kmalloc(sizeof(*pdev->dev.dma_mask), GFP_KERNEL);
+	if (!pdev->dev.dma_mask) {
+		ret = -ENOMEM;
+		goto dev_put;
+	}
+
+	pdev->dev.fwnode = fwnode;
+
+	/*
+	 * Set default dma mask value for the table walker,
+	 * to be overridden on probing with correct value.
+	 */
+	*pdev->dev.dma_mask = DMA_BIT_MASK(32);
+	pdev->dev.coherent_dma_mask = *pdev->dev.dma_mask;
+
+	attr = ops->iommu_is_coherent(node) ?
+			     DEV_DMA_COHERENT : DEV_DMA_NON_COHERENT;
+
+	/* Configure DMA for the page table walker */
+	acpi_dma_configure(&pdev->dev, attr);
+
+	ret = platform_device_add(pdev);
+	if (ret)
+		goto dma_deconfigure;
+
+	iort_set_fwnode(node, pdev->dev.fwnode);
+
+	return 0;
+
+dma_deconfigure:
+	acpi_dma_deconfigure(&pdev->dev);
+	kfree(pdev->dev.dma_mask);
+
+dev_put:
+	platform_device_put(pdev);
+
+	return ret;
+}
+
 void __init iort_table_detect(void)
 {
 	acpi_status status;
diff --git a/include/linux/iort.h b/include/linux/iort.h
index ac2706a..18e6836 100644
--- a/include/linux/iort.h
+++ b/include/linux/iort.h
@@ -31,6 +31,9 @@ bool iort_node_match(u8 type);
 void iort_table_detect(void);
 u32 iort_msi_map_rid(struct device *dev, u32 req_id);
 struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id);
+/* IOMMU interface */
+int iort_add_smmu_platform_device(struct fwnode_handle *fwnode,
+				  struct acpi_iort_node *node);
 #else
 static inline bool iort_node_match(u8 type) { return false; }
 static inline void iort_table_detect(void) { }
@@ -38,6 +41,13 @@ static inline u32 iort_msi_map_rid(struct device *dev, u32 req_id)
 { return req_id; }
 static inline struct irq_domain *
 iort_get_device_domain(struct device *dev, u32 req_id) { return NULL; }
+/* IOMMU interface */
+static inline int
+iort_add_smmu_platform_device(struct fwnode_handle *fwnode,
+			      struct acpi_iort_node *node)
+{
+	return -ENODEV;
+}
 #endif
 
 #define IORT_ACPI_DECLARE(name, table_id, fn)		\
-- 
2.6.4