[PATCH 1/9] ACPI: Add support for AMBA bus type

[Wang Hongcheng <annie.wang@amd.com>]

From: Huang Rui <ray.huang@amd.com>

Inspired by acpi platform bus type, to make driver "porting" more
straightforward, this patch introduces ACPI support to the AMBA bus
type. Instead of writing ACPI "glue" drivers for the exiting AMBA
drivers.

In the subsequent patches, we will use this function to support pl330
AMBA driver.

Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Wang Hongcheng <annie.wang@amd.com>
---
 drivers/acpi/Makefile    |   1 +
 drivers/acpi/acpi_amba.c | 157 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/acpi.h     |  21 +++++++
 3 files changed, 179 insertions(+)
 create mode 100644 drivers/acpi/acpi_amba.c

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 675eaf3..7d84446 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -42,6 +42,7 @@ acpi-$(CONFIG_ACPI_DOCK)	+= dock.o
 acpi-y				+= pci_root.o pci_link.o pci_irq.o
 acpi-y				+= acpi_lpss.o acpi_apd.o
 acpi-y				+= acpi_platform.o
+acpi-$(CONFIG_ARM_AMBA)		+= acpi_amba.o
 acpi-y				+= acpi_pnp.o
 acpi-y				+= int340x_thermal.o
 acpi-y				+= power.o
diff --git a/drivers/acpi/acpi_amba.c b/drivers/acpi/acpi_amba.c
new file mode 100644
index 0000000..4f0366a
--- /dev/null
+++ b/drivers/acpi/acpi_amba.c
@@ -0,0 +1,157 @@
+/*
+ * ACPI support for AMBA bus type.
+ *
+ * Copyright (C) 2015, Advanced Micro Devices, Inc.
+ * Authors: Huang Rui <ray.huang@amd.com>
+ *          Wang Hongcheng <annie.wang@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/dma-mapping.h>
+#include <linux/amba/bus.h>
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/clk.h>
+
+#include "internal.h"
+
+ACPI_MODULE_NAME("amba");
+
+/**
+ * acpi_create_amba_device - Create AMBA device for ACPI device node.
+ * @adev: ACPI device node to create an AMBA device.
+ * @periphid: AMBA device periphid.
+ * @fixed_rate: Clock frequency.
+ * @pdata: Platform data specific to the device.
+ *
+ * Check if the given @adev can be represented as an AMBA device and, if
+ * that's the case, create and register an AMBA device, populate its
+ * common resources and returns a pointer to it.  Otherwise, return
+ * %NULL or ERR_PTR() on error.
+ *
+ * Name of the AMBA device will be the same as @adev's.
+ */
+struct amba_device *acpi_create_amba_device(struct acpi_device *adev,
+					    unsigned int periphid,
+					    unsigned long fixed_rate,
+					    void *pdata)
+{
+	struct amba_device *amba_dev = NULL;
+	struct device *parent;
+	struct acpi_device *acpi_parent;
+	struct resource_entry *rentry;
+	struct list_head resource_list;
+	struct resource *resource = NULL;
+	int count, ret = 0;
+	unsigned int i;
+	unsigned int irq[AMBA_NR_IRQS];
+	struct clk *clk = ERR_PTR(-ENODEV);
+
+	/*
+	 * If the ACPI node already has a physical device attached,
+	 * skip it.
+	 */
+	if (adev->physical_node_count)
+		return NULL;
+
+	INIT_LIST_HEAD(&resource_list);
+	count = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
+	if (count <= 0)
+		return NULL;
+
+	resource = kzalloc(sizeof(*resource), GFP_KERNEL);
+	if (!resource)
+		goto resource_alloc_err;
+
+	count = 0;
+	list_for_each_entry(rentry, &resource_list, node) {
+		if (resource_type(rentry->res) == IORESOURCE_IRQ) {
+			irq[count] = rentry->res->start;
+			count++;
+		}
+		/*
+		 * there is only one io memory resource entry
+		 * at current AMBA device design
+		 */
+		if (resource_type(rentry->res) | IORESOURCE_MEM)
+			memcpy(resource, rentry->res, sizeof(struct resource));
+	}
+
+	amba_dev = amba_device_alloc(dev_name(&adev->dev),
+				     resource->start,
+				     resource_size(resource));
+
+	if (!amba_dev)
+		goto amba_alloc_err;
+
+	amba_dev->dev.coherent_dma_mask = acpi_dma_supported(adev) ? DMA_BIT_MASK(64) : 0;
+	amba_dev->dev.platform_data = pdata;
+	amba_dev->dev.fwnode = acpi_fwnode_handle(adev);
+
+	/*
+	 * If the ACPI node has a parent and that parent has a
+	 * physical device attached to it, that physical device should
+	 * be the parent of the AMBA device we are about to create.
+	 */
+	parent = NULL;
+	acpi_parent = adev->parent;
+	if (acpi_parent) {
+		struct acpi_device_physical_node *entry;
+		struct list_head *list;
+
+		mutex_lock(&acpi_parent->physical_node_lock);
+		list = &acpi_parent->physical_node_list;
+		if (!list_empty(list)) {
+			entry = list_first_entry(list, struct acpi_device_physical_node, node);
+			parent = entry->dev;
+		}
+		mutex_unlock(&acpi_parent->physical_node_lock);
+	}
+
+	amba_dev->dev.parent = parent;
+	amba_dev->periphid = periphid;
+
+	WARN_ON_ONCE(count > AMBA_NR_IRQS);
+
+	for (i = 0; i < count; i++)
+		amba_dev->irq[i] = irq[i];
+
+	clk = clk_register_fixed_rate(&amba_dev->dev,
+				      dev_name(&amba_dev->dev),
+				      NULL, CLK_IS_ROOT,
+				      fixed_rate);
+	if (IS_ERR_OR_NULL(clk))
+		goto amba_register_err;
+
+	ret = clk_register_clkdev(clk, "apb_pclk",
+				  dev_name(&amba_dev->dev));
+	if (ret)
+		goto amba_register_err;
+
+	ret = amba_device_add(amba_dev, resource);
+	if (ret)
+		goto amba_register_err;
+
+	acpi_dev_free_resource_list(&resource_list);
+	kfree(resource);
+	return amba_dev;
+
+amba_register_err:
+	amba_device_put(amba_dev);
+
+amba_alloc_err:
+	kfree(resource);
+
+resource_alloc_err:
+	acpi_dev_free_resource_list(&resource_list);
+
+	return ERR_PTR(ret);
+}
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 0548339..04827d8 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -37,6 +37,7 @@
 #include <linux/list.h>
 #include <linux/mod_devicetable.h>
 #include <linux/dynamic_debug.h>
+#include <linux/amba/bus.h>
 
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
@@ -466,6 +467,26 @@ int acpi_device_modalias(struct device *, char *, int);
 void acpi_walk_dep_device_list(acpi_handle handle);
 
 struct platform_device *acpi_create_platform_device(struct acpi_device *);
+
+#ifdef CONFIG_ARM_AMBA
+
+struct amba_device *acpi_create_amba_device(struct acpi_device *adev,
+					    unsigned int periphid,
+					    unsigned long fixed_rate,
+					    void *pdata);
+
+#else /* !CONFIG_ARM_AMBA */
+
+static inline struct amba_device *acpi_create_amba_device(struct acpi_device *adev,
+							  unsigned int periphid,
+							  unsigned long fixed_rate,
+							  void *pdata)
+{
+	return NULL;
+}
+
+#endif
+
 #define ACPI_PTR(_ptr)	(_ptr)
 
 #else	/* !CONFIG_ACPI */
-- 
1.9.1