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Subject[PATCH v5 2/2] ACPI: amba bus probing support
Date
From: Graeme Gregory <graeme.gregory@linaro.org>

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.

Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
---
drivers/acpi/Makefile | 1 +
drivers/acpi/acpi_amba.c | 122 +++++++++++++++++++++++++++++++++++++++++++++++
drivers/acpi/internal.h | 5 ++
drivers/acpi/scan.c | 1 +
4 files changed, 129 insertions(+)
create mode 100644 drivers/acpi/acpi_amba.c

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 675eaf3..3cf732f 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-$(CONFIG_ARM_AMBA) += 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..2a61b54
--- /dev/null
+++ b/drivers/acpi/acpi_amba.c
@@ -0,0 +1,122 @@
+
+/*
+ * ACPI support for platform bus type.
+ *
+ * Copyright (C) 2015, Linaro Ltd
+ * Author: Graeme Gregory <graeme.gregory@linaro.org>
+ *
+ * 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>
+
+#include "internal.h"
+
+static const struct acpi_device_id amba_id_list[] = {
+ {"ARMH0061", 0}, /* PL061 GPIO Device */
+ {"", 0},
+};
+
+static void amba_register_dummy_clk(void)
+{
+ static struct clk *amba_dummy_clk;
+
+ /* If clock already registered */
+ if (amba_dummy_clk)
+ return;
+
+ amba_dummy_clk = clk_register_fixed_rate(NULL, "apb_pclk", NULL,
+ CLK_IS_ROOT, 0);
+ clk_register_clkdev(amba_dummy_clk, "apb_pclk", NULL);
+}
+
+static int amba_handler_attach(struct acpi_device *adev,
+ const struct acpi_device_id *id)
+{
+ struct amba_device *dev;
+ struct resource_entry *rentry;
+ struct list_head resource_list;
+ bool address_found = false;
+ int irq_no = 0;
+ int ret;
+
+ /* If the ACPI node already has a physical device attached, skip it. */
+ if (adev->physical_node_count)
+ return 0;
+
+ dev = amba_device_alloc(dev_name(&adev->dev), 0, 0);
+ if (!dev) {
+ dev_err(&adev->dev, "%s(): amba_device_alloc() failed\n",
+ __func__);
+ return -ENOMEM;
+ }
+
+ INIT_LIST_HEAD(&resource_list);
+ ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
+ if (ret < 0)
+ goto err_free;
+
+ 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");
+ break;
+ }
+ }
+
+ 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 amba device we are about to create.
+ */
+ if (adev->parent)
+ dev->dev.parent = acpi_get_first_physical_node(adev->parent);
+
+ ACPI_COMPANION_SET(&dev->dev, adev);
+
+ ret = amba_device_add(dev, &iomem_resource);
+ if (ret) {
+ dev_err(&adev->dev, "%s(): amba_device_add() failed (%d)\n",
+ __func__, ret);
+ goto err_free;
+ }
+
+ return 1;
+
+err_free:
+ amba_device_put(dev);
+ return ret;
+}
+
+static struct acpi_scan_handler amba_handler = {
+ .ids = amba_id_list,
+ .attach = amba_handler_attach,
+};
+
+void __init acpi_amba_init(void)
+{
+ amba_register_dummy_clk();
+ acpi_scan_add_handler(&amba_handler);
+}
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index ee9312ba..6086f66 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -29,6 +29,11 @@ void acpi_processor_init(void);
void acpi_platform_init(void);
void acpi_pnp_init(void);
void acpi_int340x_thermal_init(void);
+#ifdef CONFIG_ARM_AMBA
+void acpi_amba_init(void);
+#else
+static inline void acpi_amba_init(void) {}
+#endif
int acpi_sysfs_init(void);
void acpi_container_init(void);
void acpi_memory_hotplug_init(void);
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 78d5f02..20c8cba 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1922,6 +1922,7 @@ int __init acpi_scan_init(void)
acpi_memory_hotplug_init();
acpi_pnp_init();
acpi_int340x_thermal_init();
+ acpi_amba_init();

acpi_scan_add_handler(&generic_device_handler);

--
2.7.0
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