[PATCH v5 07/14] 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/arm64/iort.c | 131 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 131 insertions(+)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index b89b3d3..e0a9b16 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/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 {
@@ -424,6 +425,135 @@ 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
+ * @fwnode: IORT node associated fwnode handle
+ * @node: Pointer to SMMU ACPI IORT node
+ *
+ * Returns: 0 on success, <0 failure
+ */
+static int __init 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_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;
+
+	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;
+
+	return 0;
+
+dma_deconfigure:
+	acpi_dma_deconfigure(&pdev->dev);
+	kfree(pdev->dev.dma_mask);
+
+dev_put:
+	platform_device_put(pdev);
+
+	return ret;
+}
+
+static acpi_status __init iort_match_iommu_callback(struct acpi_iort_node *node,
+						    void *context)
+{
+	int ret;
+	struct fwnode_handle *fwnode;
+
+	fwnode = iort_get_fwnode(node);
+
+	if (!fwnode)
+		return AE_NOT_FOUND;
+
+	ret = iort_add_smmu_platform_device(fwnode, node);
+	if (ret) {
+		pr_err("Error in platform device creation\n");
+		return AE_ERROR;
+	}
+
+	return AE_OK;
+}
+
+static void __init iort_smmu_init(void)
+{
+	iort_scan_node(ACPI_IORT_NODE_SMMU, iort_match_iommu_callback, NULL);
+	iort_scan_node(ACPI_IORT_NODE_SMMU_V3, iort_match_iommu_callback, NULL);
+}
+
 void __init acpi_iort_init(void)
 {
 	acpi_status status;
@@ -436,4 +566,5 @@ void __init acpi_iort_init(void)
 	}
 
 	acpi_probe_device_table(iort);
+	iort_smmu_init();
 }
-- 
2.10.0