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