[PATCH 1/3] ACPI: amba bus probing support
From: Graeme Gregory
Date: Wed Sep 30 2015 - 06:39:43 EST
On ARM64 some devices use the AMBA device and not the platform bus for
probing so add support for this. Uses a dummy clock for apb_pclk as ACPI
does not have a suitable clock representation and to keep the core
AMBA bus code unchanged between probing methods.
Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Signed-off-by: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
---
drivers/acpi/Makefile | 1 +
drivers/acpi/acpi_amba.c | 157 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/acpi.h | 1 +
3 files changed, 159 insertions(+)
create mode 100644 drivers/acpi/acpi_amba.c
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index b5e7cd8..b94aa9f 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -43,6 +43,7 @@ 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-y += acpi_pnp.o
+acpi-y += acpi_amba.o
acpi-y += int340x_thermal.o
acpi-y += power.o
acpi-y += event.o
diff --git a/drivers/acpi/acpi_amba.c b/drivers/acpi/acpi_amba.c
new file mode 100644
index 0000000..2f45b71
--- /dev/null
+++ b/drivers/acpi/acpi_amba.c
@@ -0,0 +1,157 @@
+
+/*
+ * ACPI support for platform bus type.
+ *
+ * Copyright (C) 2015, Linaro Ltd
+ * Authors: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
+ *
+ * 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/amba/bus.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#ifdef CONFIG_ARM_AMBA
+static const struct acpi_device_id amba_id_list[] = {
+ {"ARMH0011", 0}, /* PL011 SBSA Uart */
+ {"ARMH0061", 0}, /* PL061 GPIO Device */
+ {"", 0},
+};
+
+struct clk *amba_dummy_clk;
+
+void amba_register_dummy_clk(void)
+{
+ struct clk *clk;
+
+ /* If clock already registered */
+ if (amba_dummy_clk)
+ return;
+
+ clk = clk_register_fixed_rate(NULL, "apb_pclk", NULL, CLK_IS_ROOT, 0);
+ clk_register_clkdev(clk, "apb_pclk", NULL);
+
+ amba_dummy_clk = clk;
+}
+
+/**
+ * acpi_create_amba_device - Create platform device for ACPI device node
+ * @adev: ACPI device node to create a AMBA device for.
+ *
+ * Create and register an AMBA device, populate its common
+ * resources and return a pointer to it. Otherwise, return %NULL.
+ *
+ * Name of the AMBA device will be the same as @adev's.
+ */
+struct amba_device *acpi_create_amba_device(struct acpi_device *adev)
+{
+ struct amba_device *dev = NULL;
+ struct acpi_device *acpi_parent;
+ struct resource_entry *rentry;
+ struct list_head resource_list;
+ struct resource *resources = NULL;
+ bool address_found = false;
+ int ret, count, irq_no = 0;
+
+ /* If the ACPI node already has a physical device attached, skip it. */
+ if (adev->physical_node_count)
+ return NULL;
+
+ /* AMBA devices use amba_device not platform device */
+ if (acpi_match_device_ids(adev, amba_id_list))
+ return NULL;
+
+ amba_register_dummy_clk();
+
+ dev = amba_device_alloc(NULL, 0, 0);
+ if (!dev) {
+ pr_err("%s(): amba_device_alloc() failed for %s\n",
+ __func__, dev_name(&adev->dev));
+ return NULL;
+ }
+
+ INIT_LIST_HEAD(&resource_list);
+ count = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
+ if (count < 0) {
+ return NULL;
+ } else if (count > 0) {
+ resources = kmalloc_array(count, sizeof(struct resource),
+ GFP_KERNEL);
+ if (!resources) {
+ acpi_dev_free_resource_list(&resource_list);
+ return ERR_PTR(-ENOMEM);
+ }
+ count = 0;
+ list_for_each_entry(rentry, &resource_list, node) {
+ switch (resource_type(rentry->res)) {
+ case IORESOURCE_MEM:
+ if (!address_found) {
+ dev->res = *rentry->res;
+ address_found = true;
+ }
+ break;
+ case IORESOURCE_IRQ:
+ if (irq_no < AMBA_NR_IRQS)
+ dev->irq[irq_no++] = rentry->res->start;
+ break;
+ default:
+ dev_warn(&adev->dev, "Invalid resource\n");
+ }
+ }
+ acpi_dev_free_resource_list(&resource_list);
+ }
+
+ /*
+ * 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
+ * platform device we are about to create.
+ */
+ dev->dev.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);
+ dev->dev.parent = entry->dev;
+ }
+ mutex_unlock(&acpi_parent->physical_node_lock);
+ }
+
+ dev_set_name(&dev->dev, "%s", dev_name(&adev->dev));
+ ACPI_COMPANION_SET(&dev->dev, adev);
+
+ ret = amba_device_add(dev, &iomem_resource);
+ if (ret) {
+ pr_err("%s(): amba_device_add() failed (%d) for %s\n",
+ __func__, ret, dev_name(&adev->dev));
+ goto err_free;
+ }
+
+ return dev;
+
+err_free:
+ amba_device_put(dev);
+ return NULL;
+}
+#else
+struct amba_device *acpi_create_amba_device(struct acpi_device *adev)
+{
+ return NULL;
+}
+#endif /* CONFIG_ARM_AMBA */
+EXPORT_SYMBOL_GPL(acpi_create_amba_device);
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 84e7055..dc42ec0 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -457,6 +457,7 @@ 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 *);
+struct amba_device *acpi_create_amba_device(struct acpi_device *);
#define ACPI_PTR(_ptr) (_ptr)
#else /* !CONFIG_ACPI */
--
2.4.3
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