136 lines
3.0 KiB
C
136 lines
3.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* cbmem.c
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*
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* Driver for exporting cbmem entries in sysfs.
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*
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* Copyright 2022 Google LLC
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*/
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#include <linux/device.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/kobject.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/sysfs.h>
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#include "coreboot_table.h"
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struct cbmem_entry {
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char *mem_file_buf;
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u32 size;
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};
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static struct cbmem_entry *to_cbmem_entry(struct kobject *kobj)
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{
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return dev_get_drvdata(kobj_to_dev(kobj));
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}
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static ssize_t mem_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf, loff_t pos,
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size_t count)
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{
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struct cbmem_entry *entry = to_cbmem_entry(kobj);
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return memory_read_from_buffer(buf, count, &pos, entry->mem_file_buf,
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entry->size);
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}
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static ssize_t mem_write(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf, loff_t pos,
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size_t count)
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{
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struct cbmem_entry *entry = to_cbmem_entry(kobj);
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if (pos < 0 || pos >= entry->size)
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return -EINVAL;
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if (count > entry->size - pos)
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count = entry->size - pos;
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memcpy(entry->mem_file_buf + pos, buf, count);
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return count;
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}
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static BIN_ATTR_ADMIN_RW(mem, 0);
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static ssize_t address_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct coreboot_device *cbdev = dev_to_coreboot_device(dev);
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return sysfs_emit(buf, "0x%llx\n", cbdev->cbmem_entry.address);
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}
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static DEVICE_ATTR_RO(address);
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static ssize_t size_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct coreboot_device *cbdev = dev_to_coreboot_device(dev);
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return sysfs_emit(buf, "0x%x\n", cbdev->cbmem_entry.entry_size);
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}
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static DEVICE_ATTR_RO(size);
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static struct attribute *attrs[] = {
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&dev_attr_address.attr,
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&dev_attr_size.attr,
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NULL,
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};
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static struct bin_attribute *bin_attrs[] = {
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&bin_attr_mem,
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NULL,
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};
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static const struct attribute_group cbmem_entry_group = {
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.attrs = attrs,
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.bin_attrs = bin_attrs,
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};
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static const struct attribute_group *dev_groups[] = {
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&cbmem_entry_group,
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NULL,
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};
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static int cbmem_entry_probe(struct coreboot_device *dev)
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{
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struct cbmem_entry *entry;
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entry = devm_kzalloc(&dev->dev, sizeof(*entry), GFP_KERNEL);
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if (!entry)
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return -ENOMEM;
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dev_set_drvdata(&dev->dev, entry);
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entry->mem_file_buf = devm_memremap(&dev->dev, dev->cbmem_entry.address,
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dev->cbmem_entry.entry_size,
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MEMREMAP_WB);
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if (IS_ERR(entry->mem_file_buf))
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return PTR_ERR(entry->mem_file_buf);
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entry->size = dev->cbmem_entry.entry_size;
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return 0;
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}
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static const struct coreboot_device_id cbmem_ids[] = {
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{ .tag = LB_TAG_CBMEM_ENTRY },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(coreboot, cbmem_ids);
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static struct coreboot_driver cbmem_entry_driver = {
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.probe = cbmem_entry_probe,
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.drv = {
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.name = "cbmem",
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.owner = THIS_MODULE,
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.dev_groups = dev_groups,
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},
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.id_table = cbmem_ids,
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};
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module_coreboot_driver(cbmem_entry_driver);
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MODULE_AUTHOR("Jack Rosenthal <jrosenth@chromium.org>");
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MODULE_LICENSE("GPL");
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