// SPDX-License-Identifier: GPL-2.0-or-later/* * Generic System Framebuffers * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com> */ /* * simple-framebuffer probing * Try to convert "screen_info" into a "simple-framebuffer" compatible mode. * If the mode is incompatible, we return "false" and let the caller create * legacy nodes instead. */ #include <linux/err.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/mm.h>#include <linux/platform_data/simplefb.h>#include <linux/platform_device.h>#include <linux/screen_info.h>#include <linux/sysfb.h> static const char simplefb_resname[] = "BOOTFB";static const struct simplefb_format formats[] = SIMPLEFB_FORMATS; /* try parsing screen_info into a simple-framebuffer mode struct */__init bool sysfb_parse_mode(const struct screen_info *si,			     struct simplefb_platform_data *mode){	__u8 type;	u32 bits_per_pixel;	unsigned int i; 	type = si->orig_video_isVGA;	if (type != VIDEO_TYPE_VLFB && type != VIDEO_TYPE_EFI)		return false; 	/*	 * The meaning of depth and bpp for direct-color formats is	 * inconsistent:	 *	 *  - DRM format info specifies depth as the number of color	 *    bits; including alpha, but not including filler bits.	 *  - Linux' EFI platform code computes lfb_depth from the	 *    individual color channels, including the reserved bits.	 *  - VBE 1.1 defines lfb_depth for XRGB1555 as 16, but later	 *    versions use 15.	 *  - On the kernel command line, 'bpp' of 32 is usually	 *    XRGB8888 including the filler bits, but 15 is XRGB1555	 *    not including the filler bit.	 *	 * It's not easily possible to fix this in struct screen_info,	 * as this could break UAPI. The best solution is to compute	 * bits_per_pixel from the color bits, reserved bits and	 * reported lfb_depth, whichever is highest.  In the loop below,	 * ignore simplefb formats with alpha bits, as EFI and VESA	 * don't specify alpha channels.	 */	if (si->lfb_depth > 8) {		bits_per_pixel = max(max3(si->red_size + si->red_pos,					  si->green_size + si->green_pos,					  si->blue_size + si->blue_pos),				     si->rsvd_size + si->rsvd_pos);		bits_per_pixel = max_t(u32, bits_per_pixel, si->lfb_depth);	} else {		bits_per_pixel = si->lfb_depth;	} 	for (i = 0; i < ARRAY_SIZE(formats); ++i) {		const struct simplefb_format *f = &formats[i]; 		if (f->transp.length)			continue; /* transparent formats are unsupported by VESA/EFI */ 		if (bits_per_pixel == f->bits_per_pixel &&		    si->red_size == f->red.length &&		    si->red_pos == f->red.offset &&		    si->green_size == f->green.length &&		    si->green_pos == f->green.offset &&		    si->blue_size == f->blue.length &&		    si->blue_pos == f->blue.offset) {			mode->format = f->name;			mode->width = si->lfb_width;			mode->height = si->lfb_height;			mode->stride = si->lfb_linelength;			return true;		}	} 	return false;} __init struct platform_device *sysfb_create_simplefb(const struct screen_info *si,						     const struct simplefb_platform_data *mode,						     struct device *parent){	struct platform_device *pd;	struct resource res;	u64 base, size;	u32 length;	int ret; 	/*	 * If the 64BIT_BASE capability is set, ext_lfb_base will contain the	 * upper half of the base address. Assemble the address, then make sure	 * it is valid and we can actually access it.	 */	base = si->lfb_base;	if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)		base |= (u64)si->ext_lfb_base << 32;	if (!base || (u64)(resource_size_t)base != base) {		printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n");		return ERR_PTR(-EINVAL);	} 	/*	 * Don't use lfb_size as IORESOURCE size, since it may contain the	 * entire VMEM, and thus require huge mappings. Use just the part we	 * need, that is, the part where the framebuffer is located. But verify	 * that it does not exceed the advertised VMEM.	 * Note that in case of VBE, the lfb_size is shifted by 16 bits for	 * historical reasons.	 */	size = si->lfb_size;	if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)		size <<= 16;	length = mode->height * mode->stride;	if (length > size) {		printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");		return ERR_PTR(-EINVAL);	}	length = PAGE_ALIGN(length); 	/* setup IORESOURCE_MEM as framebuffer memory */	memset(&res, 0, sizeof(res));	res.flags = IORESOURCE_MEM;	res.name = simplefb_resname;	res.start = base;	res.end = res.start + length - 1;	if (res.end <= res.start)		return ERR_PTR(-EINVAL); 	pd = platform_device_alloc("simple-framebuffer", 0);	if (!pd)		return ERR_PTR(-ENOMEM); 	pd->dev.parent = parent; 	sysfb_set_efifb_fwnode(pd); 	ret = platform_device_add_resources(pd, &res, 1);	if (ret)		goto err_put_device; 	ret = platform_device_add_data(pd, mode, sizeof(*mode));	if (ret)		goto err_put_device; 	ret = platform_device_add(pd);	if (ret)		goto err_put_device; 	return pd; err_put_device:	platform_device_put(pd); 	return ERR_PTR(ret);}