1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Generic System Framebuffers 4 * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com> 5 */ 6 7 /* 8 * simple-framebuffer probing 9 * Try to convert "screen_info" into a "simple-framebuffer" compatible mode. 10 * If the mode is incompatible, we return "false" and let the caller create 11 * legacy nodes instead. 12 */ 13 14 #include <linux/err.h> 15 #include <linux/init.h> 16 #include <linux/kernel.h> 17 #include <linux/mm.h> 18 #include <linux/platform_data/simplefb.h> 19 #include <linux/platform_device.h> 20 #include <linux/screen_info.h> 21 #include <linux/sysfb.h> 22 23 static const char simplefb_resname[] = "BOOTFB"; 24 static const struct simplefb_format formats[] = SIMPLEFB_FORMATS; 25 26 /* try parsing screen_info into a simple-framebuffer mode struct */ 27 __init bool sysfb_parse_mode(const struct screen_info *si, 28 struct simplefb_platform_data *mode) 29 { 30 const struct simplefb_format *f; 31 __u8 type; 32 unsigned int i; 33 34 type = si->orig_video_isVGA; 35 if (type != VIDEO_TYPE_VLFB && type != VIDEO_TYPE_EFI) 36 return false; 37 38 for (i = 0; i < ARRAY_SIZE(formats); ++i) { 39 f = &formats[i]; 40 if (si->lfb_depth == f->bits_per_pixel && 41 si->red_size == f->red.length && 42 si->red_pos == f->red.offset && 43 si->green_size == f->green.length && 44 si->green_pos == f->green.offset && 45 si->blue_size == f->blue.length && 46 si->blue_pos == f->blue.offset && 47 si->rsvd_size == f->transp.length && 48 si->rsvd_pos == f->transp.offset) { 49 mode->format = f->name; 50 mode->width = si->lfb_width; 51 mode->height = si->lfb_height; 52 mode->stride = si->lfb_linelength; 53 return true; 54 } 55 } 56 57 return false; 58 } 59 60 __init int sysfb_create_simplefb(const struct screen_info *si, 61 const struct simplefb_platform_data *mode) 62 { 63 struct platform_device *pd; 64 struct resource res; 65 u64 base, size; 66 u32 length; 67 int ret; 68 69 /* 70 * If the 64BIT_BASE capability is set, ext_lfb_base will contain the 71 * upper half of the base address. Assemble the address, then make sure 72 * it is valid and we can actually access it. 73 */ 74 base = si->lfb_base; 75 if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE) 76 base |= (u64)si->ext_lfb_base << 32; 77 if (!base || (u64)(resource_size_t)base != base) { 78 printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n"); 79 return -EINVAL; 80 } 81 82 /* 83 * Don't use lfb_size as IORESOURCE size, since it may contain the 84 * entire VMEM, and thus require huge mappings. Use just the part we 85 * need, that is, the part where the framebuffer is located. But verify 86 * that it does not exceed the advertised VMEM. 87 * Note that in case of VBE, the lfb_size is shifted by 16 bits for 88 * historical reasons. 89 */ 90 size = si->lfb_size; 91 if (si->orig_video_isVGA == VIDEO_TYPE_VLFB) 92 size <<= 16; 93 length = mode->height * mode->stride; 94 if (length > size) { 95 printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n"); 96 return -EINVAL; 97 } 98 length = PAGE_ALIGN(length); 99 100 /* setup IORESOURCE_MEM as framebuffer memory */ 101 memset(&res, 0, sizeof(res)); 102 res.flags = IORESOURCE_MEM | IORESOURCE_BUSY; 103 res.name = simplefb_resname; 104 res.start = base; 105 res.end = res.start + length - 1; 106 if (res.end <= res.start) 107 return -EINVAL; 108 109 pd = platform_device_alloc("simple-framebuffer", 0); 110 if (!pd) 111 return -ENOMEM; 112 113 sysfb_apply_efi_quirks(pd); 114 115 ret = platform_device_add_resources(pd, &res, 1); 116 if (ret) 117 return ret; 118 119 ret = platform_device_add_data(pd, mode, sizeof(*mode)); 120 if (ret) 121 return ret; 122 123 return platform_device_add(pd); 124 } 125