forked from Minki/linux
cae0970ee9
Fix a bug where the kernel module can't be loaded after it has been unloaded as the devices are still present and conflicting with the to be created coreboot devices. Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com> Link: https://lore.kernel.org/r/20191118101934.22526-2-patrick.rudolph@9elements.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
208 lines
4.7 KiB
C
208 lines
4.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* coreboot_table.c
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*
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* Module providing coreboot table access.
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*
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* Copyright 2017 Google Inc.
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* Copyright 2017 Samuel Holland <samuel@sholland.org>
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*/
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#include <linux/acpi.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include "coreboot_table.h"
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#define CB_DEV(d) container_of(d, struct coreboot_device, dev)
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#define CB_DRV(d) container_of(d, struct coreboot_driver, drv)
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static int coreboot_bus_match(struct device *dev, struct device_driver *drv)
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{
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struct coreboot_device *device = CB_DEV(dev);
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struct coreboot_driver *driver = CB_DRV(drv);
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return device->entry.tag == driver->tag;
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}
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static int coreboot_bus_probe(struct device *dev)
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{
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int ret = -ENODEV;
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struct coreboot_device *device = CB_DEV(dev);
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struct coreboot_driver *driver = CB_DRV(dev->driver);
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if (driver->probe)
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ret = driver->probe(device);
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return ret;
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}
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static int coreboot_bus_remove(struct device *dev)
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{
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int ret = 0;
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struct coreboot_device *device = CB_DEV(dev);
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struct coreboot_driver *driver = CB_DRV(dev->driver);
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if (driver->remove)
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ret = driver->remove(device);
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return ret;
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}
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static struct bus_type coreboot_bus_type = {
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.name = "coreboot",
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.match = coreboot_bus_match,
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.probe = coreboot_bus_probe,
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.remove = coreboot_bus_remove,
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};
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static void coreboot_device_release(struct device *dev)
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{
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struct coreboot_device *device = CB_DEV(dev);
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kfree(device);
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}
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int coreboot_driver_register(struct coreboot_driver *driver)
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{
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driver->drv.bus = &coreboot_bus_type;
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return driver_register(&driver->drv);
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}
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EXPORT_SYMBOL(coreboot_driver_register);
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void coreboot_driver_unregister(struct coreboot_driver *driver)
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{
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driver_unregister(&driver->drv);
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}
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EXPORT_SYMBOL(coreboot_driver_unregister);
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static int coreboot_table_populate(struct device *dev, void *ptr)
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{
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int i, ret;
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void *ptr_entry;
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struct coreboot_device *device;
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struct coreboot_table_entry *entry;
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struct coreboot_table_header *header = ptr;
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ptr_entry = ptr + header->header_bytes;
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for (i = 0; i < header->table_entries; i++) {
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entry = ptr_entry;
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device = kzalloc(sizeof(struct device) + entry->size, GFP_KERNEL);
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if (!device)
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return -ENOMEM;
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dev_set_name(&device->dev, "coreboot%d", i);
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device->dev.parent = dev;
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device->dev.bus = &coreboot_bus_type;
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device->dev.release = coreboot_device_release;
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memcpy(&device->entry, ptr_entry, entry->size);
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ret = device_register(&device->dev);
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if (ret) {
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put_device(&device->dev);
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return ret;
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}
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ptr_entry += entry->size;
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}
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return 0;
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}
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static int coreboot_table_probe(struct platform_device *pdev)
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{
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resource_size_t len;
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struct coreboot_table_header *header;
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struct resource *res;
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struct device *dev = &pdev->dev;
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void *ptr;
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int ret;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res)
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return -EINVAL;
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len = resource_size(res);
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if (!res->start || !len)
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return -EINVAL;
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/* Check just the header first to make sure things are sane */
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header = memremap(res->start, sizeof(*header), MEMREMAP_WB);
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if (!header)
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return -ENOMEM;
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len = header->header_bytes + header->table_bytes;
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ret = strncmp(header->signature, "LBIO", sizeof(header->signature));
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memunmap(header);
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if (ret) {
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dev_warn(dev, "coreboot table missing or corrupt!\n");
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return -ENODEV;
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}
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ptr = memremap(res->start, len, MEMREMAP_WB);
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if (!ptr)
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return -ENOMEM;
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ret = bus_register(&coreboot_bus_type);
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if (!ret) {
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ret = coreboot_table_populate(dev, ptr);
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if (ret)
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bus_unregister(&coreboot_bus_type);
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}
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memunmap(ptr);
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return ret;
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}
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static int __cb_dev_unregister(struct device *dev, void *dummy)
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{
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device_unregister(dev);
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return 0;
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}
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static int coreboot_table_remove(struct platform_device *pdev)
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{
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bus_for_each_dev(&coreboot_bus_type, NULL, NULL, __cb_dev_unregister);
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bus_unregister(&coreboot_bus_type);
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return 0;
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}
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#ifdef CONFIG_ACPI
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static const struct acpi_device_id cros_coreboot_acpi_match[] = {
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{ "GOOGCB00", 0 },
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{ "BOOT0000", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(acpi, cros_coreboot_acpi_match);
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#endif
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#ifdef CONFIG_OF
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static const struct of_device_id coreboot_of_match[] = {
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{ .compatible = "coreboot" },
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{}
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};
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MODULE_DEVICE_TABLE(of, coreboot_of_match);
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#endif
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static struct platform_driver coreboot_table_driver = {
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.probe = coreboot_table_probe,
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.remove = coreboot_table_remove,
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.driver = {
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.name = "coreboot_table",
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.acpi_match_table = ACPI_PTR(cros_coreboot_acpi_match),
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.of_match_table = of_match_ptr(coreboot_of_match),
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},
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};
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module_platform_driver(coreboot_table_driver);
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MODULE_AUTHOR("Google, Inc.");
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MODULE_LICENSE("GPL");
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