cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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framebuffer-coreboot.c (2625B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * framebuffer-coreboot.c
      4 *
      5 * Memory based framebuffer accessed through coreboot table.
      6 *
      7 * Copyright 2012-2013 David Herrmann <dh.herrmann@gmail.com>
      8 * Copyright 2017 Google Inc.
      9 * Copyright 2017 Samuel Holland <samuel@sholland.org>
     10 */
     11
     12#include <linux/device.h>
     13#include <linux/kernel.h>
     14#include <linux/mm.h>
     15#include <linux/module.h>
     16#include <linux/platform_data/simplefb.h>
     17#include <linux/platform_device.h>
     18
     19#include "coreboot_table.h"
     20
     21#define CB_TAG_FRAMEBUFFER 0x12
     22
     23static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
     24
     25static int framebuffer_probe(struct coreboot_device *dev)
     26{
     27	int i;
     28	u32 length;
     29	struct lb_framebuffer *fb = &dev->framebuffer;
     30	struct platform_device *pdev;
     31	struct resource res;
     32	struct simplefb_platform_data pdata = {
     33		.width = fb->x_resolution,
     34		.height = fb->y_resolution,
     35		.stride = fb->bytes_per_line,
     36		.format = NULL,
     37	};
     38
     39	for (i = 0; i < ARRAY_SIZE(formats); ++i) {
     40		if (fb->bits_per_pixel     == formats[i].bits_per_pixel &&
     41		    fb->red_mask_pos       == formats[i].red.offset &&
     42		    fb->red_mask_size      == formats[i].red.length &&
     43		    fb->green_mask_pos     == formats[i].green.offset &&
     44		    fb->green_mask_size    == formats[i].green.length &&
     45		    fb->blue_mask_pos      == formats[i].blue.offset &&
     46		    fb->blue_mask_size     == formats[i].blue.length &&
     47		    fb->reserved_mask_pos  == formats[i].transp.offset &&
     48		    fb->reserved_mask_size == formats[i].transp.length)
     49			pdata.format = formats[i].name;
     50	}
     51	if (!pdata.format)
     52		return -ENODEV;
     53
     54	memset(&res, 0, sizeof(res));
     55	res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
     56	res.name = "Coreboot Framebuffer";
     57	res.start = fb->physical_address;
     58	length = PAGE_ALIGN(fb->y_resolution * fb->bytes_per_line);
     59	res.end = res.start + length - 1;
     60	if (res.end <= res.start)
     61		return -EINVAL;
     62
     63	pdev = platform_device_register_resndata(&dev->dev,
     64						 "simple-framebuffer", 0,
     65						 &res, 1, &pdata,
     66						 sizeof(pdata));
     67	if (IS_ERR(pdev))
     68		pr_warn("coreboot: could not register framebuffer\n");
     69	else
     70		dev_set_drvdata(&dev->dev, pdev);
     71
     72	return PTR_ERR_OR_ZERO(pdev);
     73}
     74
     75static void framebuffer_remove(struct coreboot_device *dev)
     76{
     77	struct platform_device *pdev = dev_get_drvdata(&dev->dev);
     78
     79	platform_device_unregister(pdev);
     80}
     81
     82static struct coreboot_driver framebuffer_driver = {
     83	.probe = framebuffer_probe,
     84	.remove = framebuffer_remove,
     85	.drv = {
     86		.name = "framebuffer",
     87	},
     88	.tag = CB_TAG_FRAMEBUFFER,
     89};
     90module_coreboot_driver(framebuffer_driver);
     91
     92MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
     93MODULE_LICENSE("GPL");