This AMBA bus ACPI module provides a generic handler for compatible devices. It depends on a DSDT definition as provided in the related '0/4' email.
It uses the same common code as the device tree method to probe for a hardware ID and match up a driver for each device.
Signed-off-by: Brandon Anderson brandon.anderson@amd.com --- drivers/acpi/acpi_platform.c | 2 + drivers/amba/Makefile | 2 +- drivers/amba/acpi.c | 339 ++++++++++++++++++++++++++++++++++++++++++ include/linux/amba/acpi.h | 29 ++++ 4 files changed, 371 insertions(+), 1 deletion(-) create mode 100644 drivers/amba/acpi.c create mode 100644 include/linux/amba/acpi.h
diff --git a/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c index 37b8af8..fdfa990 100644 --- a/drivers/acpi/acpi_platform.c +++ b/drivers/acpi/acpi_platform.c @@ -36,6 +36,8 @@ static const struct acpi_device_id acpi_platform_device_ids[] = { { "LINA0007" }, /* armv8 pmu */ { "LINA0008" }, /* Fixed clock */
+ { "AMBA0000" }, + { } };
diff --git a/drivers/amba/Makefile b/drivers/amba/Makefile index 66e81c2..6d088e7 100644 --- a/drivers/amba/Makefile +++ b/drivers/amba/Makefile @@ -1,2 +1,2 @@ -obj-$(CONFIG_ARM_AMBA) += bus.o +obj-$(CONFIG_ARM_AMBA) += bus.o acpi.o obj-$(CONFIG_TEGRA_AHB) += tegra-ahb.o diff --git a/drivers/amba/acpi.c b/drivers/amba/acpi.c new file mode 100644 index 0000000..b8a9f57 --- /dev/null +++ b/drivers/amba/acpi.c @@ -0,0 +1,339 @@ +/* + * AMBA Connector Resource for ACPI + * + * Copyright (C) 2013 Advanced Micro Devices, Inc. + * + * Author: Brandon Anderson brandon.anderson@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. + */ + +#ifdef CONFIG_ACPI + +#include <linux/module.h> +#include <linux/amba/bus.h> +#include <linux/platform_device.h> +#include <linux/acpi.h> +#include <linux/clkdev.h> +#include <linux/amba/acpi.h> + +struct acpi_amba_bus_info { + struct platform_device *pdev; + struct clk *clk; + char *clk_name; +}; + +/* UUID: a706b112-bf0b-48d2-9fa3-95591a3c4c06 (randomly generated) */ +static const char acpi_amba_dsm_uuid[] = { + 0xa7, 0x06, 0xb1, 0x12, 0xbf, 0x0b, 0x48, 0xd2, + 0x9f, 0xa3, 0x95, 0x59, 0x1a, 0x3c, 0x4c, 0x06 +}; + +/* acpi_amba_dsm_lookup() + * + * Helper to parse through ACPI _DSM object for a device. Each entry + * has three fields. + */ +int acpi_amba_dsm_lookup(acpi_handle handle, + const char *tag, int index, + struct acpi_amba_dsm_entry *entry) +{ + acpi_status status; + struct acpi_object_list input; + struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; + union acpi_object params[4]; + union acpi_object *obj; + int len, match_count, i; + + /* invalidate output in case there's no entry to supply */ + entry->key = NULL; + entry->value = NULL; + + if (!acpi_has_method(handle, "_DSM")) + return -ENOENT; + + input.count = 4; + params[0].type = ACPI_TYPE_BUFFER; /* UUID */ + params[0].buffer.length = sizeof(acpi_amba_dsm_uuid); + params[0].buffer.pointer = (char *)acpi_amba_dsm_uuid; + params[1].type = ACPI_TYPE_INTEGER; /* Revision */ + params[1].integer.value = 1; + params[2].type = ACPI_TYPE_INTEGER; /* Function # */ + params[2].integer.value = 1; + params[3].type = ACPI_TYPE_PACKAGE; /* Arguments */ + params[3].package.count = 0; + params[3].package.elements = NULL; + input.pointer = params; + + status = acpi_evaluate_object_typed(handle, "_DSM", + &input, &output, ACPI_TYPE_PACKAGE); + if (ACPI_FAILURE(status)) { + pr_err("failed to get _DSM package for this device\n"); + return -ENOENT; + } + + obj = (union acpi_object *)output.pointer; + + /* parse 2 objects per entry */ + match_count = 0; + for (i = 0; (i + 2) <= obj->package.count; i += 2) { + /* key must be a string */ + len = obj->package.elements[i].string.length; + if (len <= 0) + continue; + + /* check to see if this is the entry to return */ + if (strncmp(tag, obj->package.elements[i].string.pointer, + len) != 0 || + match_count < index) { + match_count++; + continue; + } + + /* copy the key */ + entry->key = kmalloc(len + 1, GFP_KERNEL); + strncpy(entry->key, + obj->package.elements[i].string.pointer, + len); + entry->key[len] = '\0'; + + /* value is a string with space-delimited fields if necessary */ + len = obj->package.elements[i + 1].string.length; + if (len > 0) { + entry->value = kmalloc(len + 1, GFP_KERNEL); + strncpy(entry->value, + obj->package.elements[i+1].string.pointer, + len); + entry->value[len] = '\0'; + } + + break; + } + + kfree(output.pointer); + + if (entry->key == NULL) + return -ENOENT; + + return 0; +} +EXPORT_SYMBOL_GPL(acpi_amba_dsm_lookup); + +static int acpi_amba_add_resource(struct acpi_resource *ares, void *data) +{ + struct amba_device *dev = data; + struct resource r; + int irq_idx; + + switch (ares->type) { + case ACPI_RESOURCE_TYPE_FIXED_MEMORY32: + if (!acpi_dev_resource_memory(ares, &dev->res)) + pr_err("failed to map memory resource\n"); + break; + case ACPI_RESOURCE_TYPE_EXTENDED_IRQ: + for (irq_idx = 0; irq_idx < AMBA_NR_IRQS; irq_idx++) { + if (acpi_dev_resource_interrupt(ares, irq_idx, &r)) + dev->irq[irq_idx] = r.start; + else + break; + } + + break; + case ACPI_RESOURCE_TYPE_END_TAG: + /* ignore the end tag */ + break; + default: + /* log an error, but proceed with driver probe */ + pr_err("unhandled acpi resource type= %d\n", + ares->type); + break; + } + + return 1; /* Tell ACPI core that this resource has been handled */ +} + +static struct clk *acpi_amba_get_clk(acpi_handle handle, int index, + char **clk_name) +{ + struct acpi_amba_dsm_entry entry; + acpi_handle clk_handle; + struct acpi_device *adev, *clk_adev; + char *clk_path; + struct clk *clk = NULL; + int len; + + if (acpi_bus_get_device(handle, &adev)) { + pr_err("cannot get device from handle\n"); + return NULL; + } + + /* key=value format for clocks is: + * "clock-name"="apb_pclk \_SB.CLK0" + */ + if (acpi_amba_dsm_lookup(handle, "clock-name", index, &entry) != 0) + return NULL; + + /* look under the clock device for the clock that matches the entry */ + *clk_name = NULL; + len = strcspn(entry.value, " "); + if (len > 0 && (len + 1) < strlen(entry.value)) { + clk_path = entry.value + len + 1; + *clk_name = kmalloc(len + 1, GFP_KERNEL); + strncpy(*clk_name, entry.value, len); + (*clk_name)[len] = '\0'; + if (ACPI_FAILURE( + acpi_get_handle(NULL, clk_path, &clk_handle)) == 0 && + acpi_bus_get_device(clk_handle, &clk_adev) == 0) + clk = clk_get_sys(dev_name(&clk_adev->dev), *clk_name); + } else + pr_err("Invalid clock-name value format '%s' for %s\n", + entry.value, dev_name(&adev->dev)); + + kfree(entry.key); + kfree(entry.value); + + return clk; +} + +static void acpi_amba_register_clocks(struct acpi_device *adev, + struct clk *default_clk, const char *default_clk_name) +{ + struct clk *clk; + int i; + char *clk_name; + + if (default_clk) { + /* for amba_get_enable_pclk() ... */ + clk_register_clkdev(default_clk, default_clk_name, + dev_name(&adev->dev)); + /* for devm_clk_get() ... */ + clk_register_clkdev(default_clk, NULL, dev_name(&adev->dev)); + } + + for (i = 0;; i++) { + clk_name = NULL; + clk = acpi_amba_get_clk(ACPI_HANDLE(&adev->dev), i, &clk_name); + if (!clk) + break; + + clk_register_clkdev(clk, clk_name, dev_name(&adev->dev)); + + kfree(clk_name); + } +} + +/* acpi_amba_add_device() + * + * ACPI equivalent to of_amba_device_create() + */ +static acpi_status acpi_amba_add_device(acpi_handle handle, + u32 lvl_not_used, void *data, void **not_used) +{ + struct list_head resource_list; + struct acpi_device *adev; + struct amba_device *dev; + int ret; + struct acpi_amba_bus_info *bus_info = data; + struct platform_device *bus_pdev = bus_info->pdev; + + if (acpi_bus_get_device(handle, &adev)) { + pr_err("%s: acpi_bus_get_device failed\n", __func__); + return AE_OK; + } + + pr_debug("Creating amba device %s\n", dev_name(&adev->dev)); + + 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 AE_CTRL_TERMINATE; + } + + /* setup generic device info */ + dev->dev.coherent_dma_mask = ~0; + dev->dev.parent = &bus_pdev->dev; + dev_set_name(&dev->dev, "%s", dev_name(&adev->dev)); + + /* setup amba-specific device info */ + dev->dma_mask = ~0; + + ACPI_HANDLE_SET(&dev->dev, handle); + ACPI_HANDLE_SET(&adev->dev, handle); + + INIT_LIST_HEAD(&resource_list); + acpi_dev_get_resources(adev, &resource_list, + acpi_amba_add_resource, dev); + acpi_dev_free_resource_list(&resource_list); + + /* Add clocks */ + acpi_amba_register_clocks(adev, bus_info->clk, bus_info->clk_name); + + /* Read AMBA hardware ID and add device to system. If a driver matching + * hardware ID has already been registered, bind this device to it. + * Otherwise, the platform subsystem will match up the hardware ID + * when the matching driver is registered. + */ + 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 AE_OK; + +err_free: + amba_device_put(dev); + + return AE_OK; /* don't prevent other devices from being probed */ +} + +static int acpi_amba_bus_probe(struct platform_device *pdev) +{ + struct acpi_amba_bus_info bus_info; + bus_info.clk_name = NULL; + + /* see if there's a top-level clock to use as default for sub-devices */ + bus_info.clk = acpi_amba_get_clk(ACPI_HANDLE(&pdev->dev), 0, + &bus_info.clk_name); + + /* probe each device */ + bus_info.pdev = pdev; + acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_HANDLE(&pdev->dev), 1, + acpi_amba_add_device, NULL, &bus_info, NULL); + + kfree(bus_info.clk_name); + + return 0; +} + +static const struct acpi_device_id amba_bus_acpi_match[] = { + { "AMBA0000", 0 }, + { }, +}; + +static struct platform_driver amba_bus_acpi_driver = { + .driver = { + .name = "amba-acpi", + .owner = THIS_MODULE, + .acpi_match_table = ACPI_PTR(amba_bus_acpi_match), + }, + .probe = acpi_amba_bus_probe, +}; + +static int __init acpi_amba_bus_init(void) +{ + return platform_driver_register(&amba_bus_acpi_driver); +} + +postcore_initcall(acpi_amba_bus_init); + +MODULE_AUTHOR("Brandon Anderson brandon.anderson@amd.com"); +MODULE_DESCRIPTION("ACPI Connector Resource for AMBA bus"); +MODULE_LICENSE("GPLv2"); +MODULE_ALIAS("platform:amba-acpi"); + +#endif /* CONFIG_ACPI */ diff --git a/include/linux/amba/acpi.h b/include/linux/amba/acpi.h new file mode 100644 index 0000000..40a72b2 --- /dev/null +++ b/include/linux/amba/acpi.h @@ -0,0 +1,29 @@ +/* + * AMBA bus ACPI helpers + * + * Copyright (C) 2013 Advanced Micro Devices, Inc. + * + * Author: Brandon Anderson brandon.anderson@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. + */ +#ifndef __ARM_AMBA_ACPI_H__ +#define __ARM_AMBA_ACPI_H__ + +#ifdef CONFIG_ACPI +#include <linux/acpi.h> + +struct acpi_amba_dsm_entry { + char *key; + char *value; +}; + +int acpi_amba_dsm_lookup(acpi_handle handle, + const char *tag, int index, + struct acpi_amba_dsm_entry *entry); + +#endif + +#endif