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: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index cb648a49543a55a091b7ba756c628d7a076ac428..edeb2d1d99bec7b605a1385d1c5e8405da6bef40 100644 (file)
--- 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 (file)
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 8668891cb1fa91a27bf1bc683700aeec65da784e..9860df04b7c259ec6b12aa8abb7ebf7088d22bf3 100644 (file)
--- 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 407a3760e8de659863fb4f6cea274a78bf11ff7b..5f28cf7783490e1da56d12378d7c3fba0e52185e 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -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);