// SPDX-License-Identifier: GPL-2.0-only/* * framebuffer-coreboot.c * * Memory based framebuffer accessed through coreboot table. * * Copyright 2012-2013 David Herrmann <dh.herrmann@gmail.com> * Copyright 2017 Google Inc. * Copyright 2017 Samuel Holland <samuel@sholland.org> */ #include <linux/device.h>#include <linux/kernel.h>#include <linux/mm.h>#include <linux/device-id/coreboot.h>#include <linux/module.h>#include <linux/pci.h>#include <linux/platform_data/simplefb.h>#include <linux/platform_device.h>#include <linux/sysfb.h> #include "coreboot_table.h" #if defined(CONFIG_PCI)static bool framebuffer_pci_dev_is_enabled(struct pci_dev *pdev){	/*	 * TODO: Try to integrate this code into the PCI subsystem	 */	int ret;	u16 command; 	ret = pci_read_config_word(pdev, PCI_COMMAND, &command);	if (ret != PCIBIOS_SUCCESSFUL)		return false;	if (!(command & PCI_COMMAND_MEMORY))		return false;	return true;} static struct pci_dev *framebuffer_parent_pci_dev(struct resource *res){	struct pci_dev *pdev = NULL;	const struct resource *r = NULL; 	while (!r && (pdev = pci_get_base_class(PCI_BASE_CLASS_DISPLAY, pdev)))		r = pci_find_resource(pdev, res); 	if (!r || !pdev)		return NULL; /* not found; not an error */ 	if (!framebuffer_pci_dev_is_enabled(pdev)) {		pci_dev_put(pdev);		return ERR_PTR(-ENODEV);	} 	return pdev;}#elsestatic struct pci_dev *framebuffer_parent_pci_dev(struct resource *res){	return NULL;}#endif static struct device *framebuffer_parent_dev(struct resource *res){	struct pci_dev *pdev; 	pdev = framebuffer_parent_pci_dev(res);	if (IS_ERR(pdev))		return ERR_CAST(pdev);	else if (pdev)		return &pdev->dev; 	return NULL;} static int framebuffer_probe(struct coreboot_device *dev){	struct lb_framebuffer *fb = &dev->framebuffer;	struct device *parent;	struct platform_device *pdev;	struct resource res;	int ret;#if !IS_ENABLED(CONFIG_DRM_COREBOOTDRM)	struct simplefb_platform_data pdata = {		.width = fb->x_resolution,		.height = fb->y_resolution,		.stride = fb->bytes_per_line,		.format = NULL,	};	int i;	static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;#endif 	/*	 * On coreboot systems, the advertised LB_TAG_FRAMEBUFFER entry	 * in the coreboot table should only be used if the payload did	 * not pass a framebuffer information to the Linux kernel.	 *	 * If the global screen_info data has been filled, the Generic	 * System Framebuffers (sysfb) will already register a platform	 * device and pass that screen_info as platform_data to a driver	 * that can scan-out using the system provided framebuffer.	 */	if (sysfb_handles_screen_info())		return -ENODEV; 	if (!fb->physical_address)		return -ENODEV; 	res = DEFINE_RES_MEM(fb->physical_address,			     PAGE_ALIGN(fb->y_resolution * fb->bytes_per_line));	if (res.end <= res.start)		return -EINVAL; 	parent = framebuffer_parent_dev(&res);	if (IS_ERR(parent))		return PTR_ERR(parent); #if IS_ENABLED(CONFIG_DRM_COREBOOTDRM)	pdev = platform_device_register_resndata(parent, "coreboot-framebuffer", 0,						 &res, 1, fb, fb->size);	if (IS_ERR(pdev)) {		pr_warn("coreboot: could not register framebuffer\n");		ret = PTR_ERR(pdev);		goto out_put_device_parent;	}#else	/*	 * FIXME: Coreboot systems should use a driver that binds to	 *        coreboot-framebuffer devices. Remove support for	 *        simple-framebuffer at some point.	 */	for (i = 0; i < ARRAY_SIZE(formats); ++i) {		if (fb->bits_per_pixel     == formats[i].bits_per_pixel &&		    fb->red_mask_pos       == formats[i].red.offset &&		    fb->red_mask_size      == formats[i].red.length &&		    fb->green_mask_pos     == formats[i].green.offset &&		    fb->green_mask_size    == formats[i].green.length &&		    fb->blue_mask_pos      == formats[i].blue.offset &&		    fb->blue_mask_size     == formats[i].blue.length)			pdata.format = formats[i].name;	}	if (!pdata.format) {		ret = -ENODEV;		goto out_put_device_parent;	} 	pdev = platform_device_register_resndata(parent,						 "simple-framebuffer", 0,						 &res, 1, &pdata,						 sizeof(pdata));	if (IS_ERR(pdev)) {		ret = PTR_ERR(pdev);		pr_warn("coreboot: could not register framebuffer\n");		goto out_put_device_parent;	}#endif 	ret = 0; out_put_device_parent:	if (parent)		put_device(parent);	return ret;} static const struct coreboot_device_id framebuffer_ids[] = {	{ .tag = CB_TAG_FRAMEBUFFER },	{ /* sentinel */ }};MODULE_DEVICE_TABLE(coreboot, framebuffer_ids); static struct coreboot_driver framebuffer_driver = {	.probe = framebuffer_probe,	.drv = {		.name = "framebuffer",	},	.id_table = framebuffer_ids,};module_coreboot_driver(framebuffer_driver); MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");MODULE_DESCRIPTION("Memory based framebuffer accessed through coreboot table");MODULE_LICENSE("GPL");