Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) /* NOMMU mmap support for RomFS on MTD devices
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4)  * Copyright © 2007 Red Hat, Inc. All Rights Reserved.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5)  * Written by David Howells (dhowells@redhat.com)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) #include <linux/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) #include <linux/mtd/super.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include "internal.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13)  * try to determine where a shared mapping can be made
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)  *   mappings)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16)  * - attempts to map through to the underlying MTD device
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) static unsigned long romfs_get_unmapped_area(struct file *file,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) 					     unsigned long addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) 					     unsigned long len,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 					     unsigned long pgoff,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 					     unsigned long flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 	struct inode *inode = file->f_mapping->host;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) 	struct mtd_info *mtd = inode->i_sb->s_mtd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 	unsigned long isize, offset, maxpages, lpages;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 	if (!mtd)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 		return (unsigned long) -ENOSYS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 	/* the mapping mustn't extend beyond the EOF */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 	lpages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 	isize = i_size_read(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 	offset = pgoff << PAGE_SHIFT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 	maxpages = (isize + PAGE_SIZE - 1) >> PAGE_SHIFT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 	if ((pgoff >= maxpages) || (maxpages - pgoff < lpages))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 		return (unsigned long) -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 	if (addr != 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 		return (unsigned long) -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 	if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 		return (unsigned long) -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) 	offset += ROMFS_I(inode)->i_dataoffset;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) 	if (offset >= mtd->size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 		return (unsigned long) -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) 	/* the mapping mustn't extend beyond the EOF */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) 	if ((offset + len) > mtd->size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) 		len = mtd->size - offset;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) 	ret = mtd_get_unmapped_area(mtd, len, offset, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) 	if (ret == -EOPNOTSUPP)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) 		ret = -ENOSYS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) 	return (unsigned long) ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61)  * permit a R/O mapping to be made directly through onto an MTD device if
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62)  * possible
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) static int romfs_mmap(struct file *file, struct vm_area_struct *vma)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) 	return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -ENOSYS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) static unsigned romfs_mmap_capabilities(struct file *file)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) 	struct mtd_info *mtd = file_inode(file)->i_sb->s_mtd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) 	if (!mtd)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) 		return NOMMU_MAP_COPY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) 	return mtd_mmap_capabilities(mtd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) const struct file_operations romfs_ro_fops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) 	.llseek			= generic_file_llseek,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) 	.read_iter		= generic_file_read_iter,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) 	.splice_read		= generic_file_splice_read,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) 	.mmap			= romfs_mmap,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) 	.get_unmapped_area	= romfs_get_unmapped_area,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) 	.mmap_capabilities	= romfs_mmap_capabilities,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) };