1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/fb.h> 4 #include <linux/module.h> 5 #include <linux/uaccess.h> 6 fb_io_read(struct fb_info * info,char __user * buf,size_t count,loff_t * ppos)7 ssize_t fb_io_read(struct fb_info *info, char __user *buf, size_t count, loff_t *ppos) 8 { 9 unsigned long p = *ppos; 10 u8 *buffer, *dst; 11 u8 __iomem *src; 12 int c, cnt = 0, err = 0; 13 unsigned long total_size, trailing; 14 15 if (info->flags & FBINFO_VIRTFB) 16 fb_warn_once(info, "Framebuffer is not in I/O address space."); 17 18 if (!info->screen_base) 19 return -ENODEV; 20 21 total_size = info->screen_size; 22 23 if (total_size == 0) 24 total_size = info->fix.smem_len; 25 26 if (p >= total_size) 27 return 0; 28 29 if (count >= total_size) 30 count = total_size; 31 32 if (count + p > total_size) 33 count = total_size - p; 34 35 buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count, 36 GFP_KERNEL); 37 if (!buffer) 38 return -ENOMEM; 39 40 src = (u8 __iomem *) (info->screen_base + p); 41 42 if (info->fbops->fb_sync) 43 info->fbops->fb_sync(info); 44 45 while (count) { 46 c = (count > PAGE_SIZE) ? PAGE_SIZE : count; 47 dst = buffer; 48 fb_memcpy_fromio(dst, src, c); 49 dst += c; 50 src += c; 51 52 trailing = copy_to_user(buf, buffer, c); 53 if (trailing == c) { 54 err = -EFAULT; 55 break; 56 } 57 c -= trailing; 58 59 *ppos += c; 60 buf += c; 61 cnt += c; 62 count -= c; 63 } 64 65 kfree(buffer); 66 67 return cnt ? cnt : err; 68 } 69 EXPORT_SYMBOL(fb_io_read); 70 fb_io_write(struct fb_info * info,const char __user * buf,size_t count,loff_t * ppos)71 ssize_t fb_io_write(struct fb_info *info, const char __user *buf, size_t count, loff_t *ppos) 72 { 73 unsigned long p = *ppos; 74 u8 *buffer, *src; 75 u8 __iomem *dst; 76 int c, cnt = 0, err = 0; 77 unsigned long total_size, trailing; 78 79 if (info->flags & FBINFO_VIRTFB) 80 fb_warn_once(info, "Framebuffer is not in I/O address space."); 81 82 if (!info->screen_base) 83 return -ENODEV; 84 85 total_size = info->screen_size; 86 87 if (total_size == 0) 88 total_size = info->fix.smem_len; 89 90 if (p > total_size) 91 return -EFBIG; 92 93 if (count > total_size) { 94 err = -EFBIG; 95 count = total_size; 96 } 97 98 if (count + p > total_size) { 99 if (!err) 100 err = -ENOSPC; 101 102 count = total_size - p; 103 } 104 105 buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count, 106 GFP_KERNEL); 107 if (!buffer) 108 return -ENOMEM; 109 110 dst = (u8 __iomem *) (info->screen_base + p); 111 112 if (info->fbops->fb_sync) 113 info->fbops->fb_sync(info); 114 115 while (count) { 116 c = (count > PAGE_SIZE) ? PAGE_SIZE : count; 117 src = buffer; 118 119 trailing = copy_from_user(src, buf, c); 120 if (trailing == c) { 121 err = -EFAULT; 122 break; 123 } 124 c -= trailing; 125 126 fb_memcpy_toio(dst, src, c); 127 dst += c; 128 src += c; 129 *ppos += c; 130 buf += c; 131 cnt += c; 132 count -= c; 133 } 134 135 kfree(buffer); 136 137 return (cnt) ? cnt : err; 138 } 139 EXPORT_SYMBOL(fb_io_write); 140 fb_io_mmap(struct fb_info * info,struct vm_area_struct * vma)141 int fb_io_mmap(struct fb_info *info, struct vm_area_struct *vma) 142 { 143 unsigned long start = info->fix.smem_start; 144 u32 len = info->fix.smem_len; 145 unsigned long mmio_pgoff = PAGE_ALIGN((start & ~PAGE_MASK) + len) >> PAGE_SHIFT; 146 147 if (info->flags & FBINFO_VIRTFB) 148 fb_warn_once(info, "Framebuffer is not in I/O address space."); 149 150 /* 151 * This can be either the framebuffer mapping, or if pgoff points 152 * past it, the mmio mapping. 153 */ 154 if (vma->vm_pgoff >= mmio_pgoff) { 155 if (info->var.accel_flags) 156 return -EINVAL; 157 158 vma->vm_pgoff -= mmio_pgoff; 159 start = info->fix.mmio_start; 160 len = info->fix.mmio_len; 161 } 162 163 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); 164 vma->vm_page_prot = pgprot_framebuffer(vma->vm_page_prot, vma->vm_start, 165 vma->vm_end, start); 166 167 return vm_iomap_memory(vma, start, len); 168 } 169 EXPORT_SYMBOL(fb_io_mmap); 170 171 MODULE_DESCRIPTION("Fbdev helpers for framebuffers in I/O memory"); 172 MODULE_LICENSE("GPL"); 173