[PATCH v6 09/16] 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@xxxxxxx>
Cc: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
Cc: Tomasz Nowicki <tn@xxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
---
 drivers/acpi/arm64/iort.c | 151 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 1433de3..2eda2f5 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -19,9 +19,11 @@
 #define pr_fmt(fmt)	"ACPI: IORT: " fmt
 
 #include <linux/acpi_iort.h>
+#include <linux/iommu.h>
 #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 {
@@ -457,6 +459,153 @@ struct irq_domain *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 __init
+const struct iort_iommu_config *iort_get_iommu_cfg(struct acpi_iort_node *node)
+{
+	return NULL;
+}
+
+/**
+ * iort_add_smmu_platform_device() - Allocate a platform device for SMMU
+ * @node: Pointer to SMMU ACPI IORT node
+ *
+ * Returns: 0 on success, <0 failure
+ */
+static int __init iort_add_smmu_platform_device(struct acpi_iort_node *node)
+{
+	struct fwnode_handle *fwnode;
+	struct platform_device *pdev;
+	struct resource *r;
+	enum dev_dma_attr attr;
+	int ret, count;
+	const struct iort_iommu_config *ops = iort_get_iommu_cfg(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;
+
+	/*
+	 * We expect the dma masks to be equivalent for
+	 * all SMMUs set-ups
+	 */
+	pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
+
+	fwnode = iort_get_fwnode(node);
+
+	if (!fwnode) {
+		ret = -ENODEV;
+		goto dev_put;
+	}
+
+	pdev->dev.fwnode = fwnode;
+
+	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;
+
+	return 0;
+
+dma_deconfigure:
+	acpi_dma_deconfigure(&pdev->dev);
+dev_put:
+	platform_device_put(pdev);
+
+	return ret;
+}
+
+static void __init iort_init_platform_devices(void)
+{
+	struct acpi_iort_node *iort_node, *iort_end;
+	struct acpi_table_iort *iort;
+	struct fwnode_handle *fwnode;
+	int i, ret;
+
+	/*
+	 * iort_table and iort both point to the start of IORT table, but
+	 * have different struct types
+	 */
+	iort = (struct acpi_table_iort *)iort_table;
+
+	/* Get the first IORT node */
+	iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort,
+				 iort->node_offset);
+	iort_end = ACPI_ADD_PTR(struct acpi_iort_node, iort,
+				iort_table->length);
+
+	for (i = 0; i < iort->node_count; i++) {
+		if (iort_node >= iort_end) {
+			pr_err("iort node pointer overflows, bad table\n");
+			return;
+		}
+
+		if ((iort_node->type == ACPI_IORT_NODE_SMMU) ||
+			(iort_node->type == ACPI_IORT_NODE_SMMU_V3)) {
+
+			fwnode = acpi_alloc_fwnode_static();
+			if (!fwnode)
+				return;
+
+			iort_set_fwnode(iort_node, fwnode);
+
+			ret = iort_add_smmu_platform_device(iort_node);
+			if (ret) {
+				iort_delete_fwnode(iort_node);
+				acpi_free_fwnode_static(fwnode);
+				return;
+			}
+		}
+
+		iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort_node,
+					 iort_node->length);
+	}
+}
+
 void __init acpi_iort_init(void)
 {
 	acpi_status status;
@@ -468,5 +617,7 @@ void __init acpi_iort_init(void)
 		return;
 	}
 
+	iort_init_platform_devices();
+
 	acpi_probe_device_table(iort);
 }
-- 
2.10.0