// SPDX-License-Identifier: GPL-2.0-only /* flash.c: Allow mmap access to the OBP Flash, for OBP updates. * * Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be) */ #include <linux/module.h> #include <linux/types.h> #include <linux/errno.h> #include <linux/miscdevice.h> #include <linux/fcntl.h> #include <linux/poll.h> #include <linux/mutex.h> #include <linux/spinlock.h> #include <linux/mm.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/uaccess.h> #include <asm/io.h> #include <asm/upa.h> static DEFINE_MUTEX(flash_mutex); static DEFINE_SPINLOCK(flash_lock); static struct { unsigned long read_base; /* Physical read address */ unsigned long write_base; /* Physical write address */ unsigned long read_size; /* Size of read area */ unsigned long write_size; /* Size of write area */ unsigned long busy; /* In use? */ } flash; static int flash_mmap(struct file *file, struct vm_area_struct *vma) { unsigned long addr; unsigned long size; spin_lock(&flash_lock); if (flash.read_base == flash.write_base) { addr = flash.read_base; size = flash.read_size; } else { if ((vma->vm_flags & VM_READ) && (vma->vm_flags & VM_WRITE)) { spin_unlock(&flash_lock); return -EINVAL; } if (vma->vm_flags & VM_READ) { addr = flash.read_base; size = flash.read_size; } else if (vma->vm_flags & VM_WRITE) { addr = flash.write_base; size = flash.write_size; } else { spin_unlock(&flash_lock); return -ENXIO; } } spin_unlock(&flash_lock); if ((vma->vm_pgoff << PAGE_SHIFT) > size) return -ENXIO; addr = vma->vm_pgoff + (addr >> PAGE_SHIFT); if (vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT)) > size) size = vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT)); vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); if (io_remap_pfn_range(vma, vma->vm_start, addr, size, vma->vm_page_prot)) return -EAGAIN; return 0; } static long long flash_llseek(struct file *file, long long offset, int origin) { mutex_lock(&flash_mutex); switch (origin) { case 0: file->f_pos = offset; break; case 1: file->f_pos += offset; if (file->f_pos > flash.read_size) file->f_pos = flash.read_size; break; case 2: file->f_pos = flash.read_size; break; default: mutex_unlock(&flash_mutex); return -EINVAL; } mutex_unlock(&flash_mutex); return file->f_pos; } static ssize_t flash_read(struct file * file, char __user * buf, size_t count, loff_t *ppos) { loff_t p = *ppos; int i; if (count > flash.read_size - p) count = flash.read_size - p; for (i = 0; i < count; i++) { u8 data = upa_readb(flash.read_base + p + i); if (put_user(data, buf)) return -EFAULT; buf++; } *ppos += count; return count; } static int flash_open(struct inode *inode, struct file *file) { mutex_lock(&flash_mutex); if (test_and_set_bit(0, (void *)&flash.busy) != 0) { mutex_unlock(&flash_mutex); return -EBUSY; } mutex_unlock(&flash_mutex); return 0; } static int flash_release(struct inode *inode, struct file *file) { spin_lock(&flash_lock); flash.busy = 0; spin_unlock(&flash_lock); return 0; } static const struct file_operations flash_fops = { /* no write to the Flash, use mmap * and play flash dependent tricks. */ .owner = THIS_MODULE, .llseek = flash_llseek, .read = flash_read, .mmap = flash_mmap, .open = flash_open, .release = flash_release, }; static struct miscdevice flash_dev = { SBUS_FLASH_MINOR, "flash", &flash_fops }; static int flash_probe(struct platform_device *op) { struct device_node *dp = op->dev.of_node; struct device_node *parent; parent = dp->parent; if (!of_node_name_eq(parent, "sbus") && !of_node_name_eq(parent, "sbi") && !of_node_name_eq(parent, "ebus")) return -ENODEV; flash.read_base = op->resource[0].start; flash.read_size = resource_size(&op->resource[0]); if (op->resource[1].flags) { flash.write_base = op->resource[1].start; flash.write_size = resource_size(&op->resource[1]); } else { flash.write_base = op->resource[0].start; flash.write_size = resource_size(&op->resource[0]); } flash.busy = 0; printk(KERN_INFO "%pOF: OBP Flash, RD %lx[%lx] WR %lx[%lx]\n", op->dev.of_node, flash.read_base, flash.read_size, flash.write_base, flash.write_size); return misc_register(&flash_dev); } static int flash_remove(struct platform_device *op) { misc_deregister(&flash_dev); return 0; } static const struct of_device_id flash_match[] = { { .name = "flashprom", }, {}, }; MODULE_DEVICE_TABLE(of, flash_match); static struct platform_driver flash_driver = { .driver = { .name = "flash", .of_match_table = flash_match, }, .probe = flash_probe, .remove = flash_remove, }; module_platform_driver(flash_driver); MODULE_LICENSE("GPL");