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Commit 6ce2e188 authored by Graeme Gregory's avatar Graeme Gregory Committed by Rafael J. Wysocki
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ACPI / scan: AMBA bus probing support 



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.

Acked-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: default avatarGraeme Gregory <graeme.gregory@linaro.org>
Signed-off-by: default avatarAleksey Makarov <aleksey.makarov@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 3b95bd16

drivers/acpi/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

drivers/acpi/acpi_amba.c

0 → 100644
+122 −0
Original line number Diff line number Diff line 


/*

 * 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);

}

drivers/acpi/internal.h

+5 −0
Original line number Diff line number Diff line
@@ -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);

drivers/acpi/scan.c

+1 −0
Original line number Diff line number Diff line
@@ -1930,6 +1930,7 @@ 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);