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 __u8 type; 31 u32 bits_per_pixel; 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 bits_per_pixel = __screen_info_lfb_bits_per_pixel(si); 39 40 for (i = 0; i < ARRAY_SIZE(formats); ++i) { 41 const struct simplefb_format *f = &formats[i]; 42 43 if (f->transp.length) 44 continue; /* transparent formats are unsupported by VESA/EFI */ 45 46 if (bits_per_pixel == f->bits_per_pixel && 47 si->red_size == f->red.length && 48 si->red_pos == f->red.offset && 49 si->green_size == f->green.length && 50 si->green_pos == f->green.offset && 51 si->blue_size == f->blue.length && 52 si->blue_pos == f->blue.offset) { 53 mode->format = f->name; 54 mode->width = si->lfb_width; 55 mode->height = si->lfb_height; 56 mode->stride = si->lfb_linelength; 57 return true; 58 } 59 } 60 61 return false; 62 } 63 64 __init struct platform_device *sysfb_create_simplefb(const struct screen_info *si, 65 const struct simplefb_platform_data *mode, 66 struct device *parent) 67 { 68 struct platform_device *pd; 69 struct resource res; 70 u64 base, size; 71 u32 length; 72 int ret; 73 74 /* 75 * If the 64BIT_BASE capability is set, ext_lfb_base will contain the 76 * upper half of the base address. Assemble the address, then make sure 77 * it is valid and we can actually access it. 78 */ 79 base = si->lfb_base; 80 if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE) 81 base |= (u64)si->ext_lfb_base << 32; 82 if (!base || (u64)(resource_size_t)base != base) { 83 printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n"); 84 return ERR_PTR(-EINVAL); 85 } 86 87 /* 88 * Don't use lfb_size as IORESOURCE size, since it may contain the 89 * entire VMEM, and thus require huge mappings. Use just the part we 90 * need, that is, the part where the framebuffer is located. But verify 91 * that it does not exceed the advertised VMEM. 92 * Note that in case of VBE, the lfb_size is shifted by 16 bits for 93 * historical reasons. 94 */ 95 size = si->lfb_size; 96 if (si->orig_video_isVGA == VIDEO_TYPE_VLFB) 97 size <<= 16; 98 length = mode->height * mode->stride; 99 if (length > size) { 100 printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n"); 101 return ERR_PTR(-EINVAL); 102 } 103 length = PAGE_ALIGN(length); 104 105 /* setup IORESOURCE_MEM as framebuffer memory */ 106 memset(&res, 0, sizeof(res)); 107 res.flags = IORESOURCE_MEM; 108 res.name = simplefb_resname; 109 res.start = base; 110 res.end = res.start + length - 1; 111 if (res.end <= res.start) 112 return ERR_PTR(-EINVAL); 113 114 pd = platform_device_alloc("simple-framebuffer", 0); 115 if (!pd) 116 return ERR_PTR(-ENOMEM); 117 118 pd->dev.parent = parent; 119 120 sysfb_set_efifb_fwnode(pd); 121 122 ret = platform_device_add_resources(pd, &res, 1); 123 if (ret) 124 goto err_put_device; 125 126 ret = platform_device_add_data(pd, mode, sizeof(*mode)); 127 if (ret) 128 goto err_put_device; 129 130 ret = platform_device_add(pd); 131 if (ret) 132 goto err_put_device; 133 134 return pd; 135 136 err_put_device: 137 platform_device_put(pd); 138 139 return ERR_PTR(ret); 140 } 141