1/*
  2 * Extensible Firmware Interface
  3 *
  4 * Based on Extensible Firmware Interface Specification version 2.4
  5 *
  6 * Copyright (C) 2013 - 2015 Linaro Ltd.
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License version 2 as
 10 * published by the Free Software Foundation.
 11 *
 12 */
 13
 14#define pr_fmt(fmt)	"efi: " fmt
 15
 16#include <linux/efi.h>
 17#include <linux/init.h>
 18#include <linux/memblock.h>
 19#include <linux/mm_types.h>
 20#include <linux/of.h>
 21#include <linux/of_fdt.h>
 22#include <linux/platform_device.h>
 23#include <linux/screen_info.h>
 24
 25#include <asm/efi.h>
 26
 27u64 efi_system_table;
 28
 29static int __init is_memory(efi_memory_desc_t *md)
 30{
 31	if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
 32		return 1;
 33	return 0;
 34}
 35
 36/*
 37 * Translate a EFI virtual address into a physical address: this is necessary,
 38 * as some data members of the EFI system table are virtually remapped after
 39 * SetVirtualAddressMap() has been called.
 40 */
 41static phys_addr_t efi_to_phys(unsigned long addr)
 42{
 43	efi_memory_desc_t *md;
 44
 45	for_each_efi_memory_desc(md) {
 46		if (!(md->attribute & EFI_MEMORY_RUNTIME))
 47			continue;
 48		if (md->virt_addr == 0)
 49			/* no virtual mapping has been installed by the stub */
 50			break;
 51		if (md->virt_addr <= addr &&
 52		    (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
 53			return md->phys_addr + addr - md->virt_addr;
 54	}
 55	return addr;
 56}
 57
 58static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;
 59
 60static __initdata efi_config_table_type_t arch_tables[] = {
 61	{LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, NULL, &screen_info_table},
 62	{NULL_GUID, NULL, NULL}
 63};
 64
 65static void __init init_screen_info(void)
 66{
 67	struct screen_info *si;
 68
 69	if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
 70		si = early_memremap_ro(screen_info_table, sizeof(*si));
 71		if (!si) {
 72			pr_err("Could not map screen_info config table\n");
 73			return;
 74		}
 75		screen_info = *si;
 76		early_memunmap(si, sizeof(*si));
 77
 78		/* dummycon on ARM needs non-zero values for columns/lines */
 79		screen_info.orig_video_cols = 80;
 80		screen_info.orig_video_lines = 25;
 81	}
 82
 83	if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
 84	    memblock_is_map_memory(screen_info.lfb_base))
 85		memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
 86}
 87
 88static int __init uefi_init(void)
 89{
 90	efi_char16_t *c16;
 91	void *config_tables;
 92	size_t table_size;
 93	char vendor[100] = "unknown";
 94	int i, retval;
 95
 96	efi.systab = early_memremap_ro(efi_system_table,
 97				       sizeof(efi_system_table_t));
 98	if (efi.systab == NULL) {
 99		pr_warn("Unable to map EFI system table.\n");
100		return -ENOMEM;
101	}
102
103	set_bit(EFI_BOOT, &efi.flags);
104	if (IS_ENABLED(CONFIG_64BIT))
105		set_bit(EFI_64BIT, &efi.flags);
106
107	/*
108	 * Verify the EFI Table
109	 */
110	if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
111		pr_err("System table signature incorrect\n");
112		retval = -EINVAL;
113		goto out;
114	}
115	if ((efi.systab->hdr.revision >> 16) < 2)
116		pr_warn("Warning: EFI system table version %d.%02d, expected 2.00 or greater\n",
117			efi.systab->hdr.revision >> 16,
118			efi.systab->hdr.revision & 0xffff);
119
120	efi.runtime_version = efi.systab->hdr.revision;
121
122	/* Show what we know for posterity */
123	c16 = early_memremap_ro(efi_to_phys(efi.systab->fw_vendor),
124				sizeof(vendor) * sizeof(efi_char16_t));
125	if (c16) {
126		for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
127			vendor[i] = c16[i];
128		vendor[i] = '\0';
129		early_memunmap(c16, sizeof(vendor) * sizeof(efi_char16_t));
130	}
131
132	pr_info("EFI v%u.%.02u by %s\n",
133		efi.systab->hdr.revision >> 16,
134		efi.systab->hdr.revision & 0xffff, vendor);
135
136	table_size = sizeof(efi_config_table_64_t) * efi.systab->nr_tables;
137	config_tables = early_memremap_ro(efi_to_phys(efi.systab->tables),
138					  table_size);
139	if (config_tables == NULL) {
140		pr_warn("Unable to map EFI config table array.\n");
141		retval = -ENOMEM;
142		goto out;
143	}
144	retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
145					 sizeof(efi_config_table_t),
146					 arch_tables);
147
148	early_memunmap(config_tables, table_size);
149out:
150	early_memunmap(efi.systab,  sizeof(efi_system_table_t));
151	return retval;
152}
153
154/*
155 * Return true for regions that can be used as System RAM.
156 */
157static __init int is_usable_memory(efi_memory_desc_t *md)
158{
159	switch (md->type) {
160	case EFI_LOADER_CODE:
161	case EFI_LOADER_DATA:
162	case EFI_BOOT_SERVICES_CODE:
163	case EFI_BOOT_SERVICES_DATA:
164	case EFI_CONVENTIONAL_MEMORY:
165	case EFI_PERSISTENT_MEMORY:
166		/*
167		 * According to the spec, these regions are no longer reserved
168		 * after calling ExitBootServices(). However, we can only use
169		 * them as System RAM if they can be mapped writeback cacheable.
170		 */
171		return (md->attribute & EFI_MEMORY_WB);
172	default:
173		break;
174	}
175	return false;
176}
177
178static __init void reserve_regions(void)
179{
180	efi_memory_desc_t *md;
181	u64 paddr, npages, size;
182
183	if (efi_enabled(EFI_DBG))
184		pr_info("Processing EFI memory map:\n");
185
186	/*
187	 * Discard memblocks discovered so far: if there are any at this
188	 * point, they originate from memory nodes in the DT, and UEFI
189	 * uses its own memory map instead.
190	 */
191	memblock_dump_all();
192	memblock_remove(0, (phys_addr_t)ULLONG_MAX);
193
194	for_each_efi_memory_desc(md) {
195		paddr = md->phys_addr;
196		npages = md->num_pages;
197
198		if (efi_enabled(EFI_DBG)) {
199			char buf[64];
200
201			pr_info("  0x%012llx-0x%012llx %s\n",
202				paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
203				efi_md_typeattr_format(buf, sizeof(buf), md));
204		}
205
206		memrange_efi_to_native(&paddr, &npages);
207		size = npages << PAGE_SHIFT;
208
209		if (is_memory(md)) {
210			early_init_dt_add_memory_arch(paddr, size);
211
212			if (!is_usable_memory(md))
213				memblock_mark_nomap(paddr, size);
214		}
215	}
216}
217
218void __init efi_init(void)
219{
220	struct efi_memory_map_data data;
221	struct efi_fdt_params params;
222
223	/* Grab UEFI information placed in FDT by stub */
224	if (!efi_get_fdt_params(&params))
225		return;
226
227	efi_system_table = params.system_table;
228
229	data.desc_version = params.desc_ver;
230	data.desc_size = params.desc_size;
231	data.size = params.mmap_size;
232	data.phys_map = params.mmap;
233
234	if (efi_memmap_init_early(&data) < 0) {
235		/*
236		* If we are booting via UEFI, the UEFI memory map is the only
237		* description of memory we have, so there is little point in
238		* proceeding if we cannot access it.
239		*/
240		panic("Unable to map EFI memory map.\n");
241	}
242
243	WARN(efi.memmap.desc_version != 1,
244	     "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
245	      efi.memmap.desc_version);
246
247	if (uefi_init() < 0) {
248		efi_memmap_unmap();
249		return;
250	}
251
252	reserve_regions();
253	efi_memattr_init();
254	efi_esrt_init();
255	efi_memmap_unmap();
256
257	memblock_reserve(params.mmap & PAGE_MASK,
258			 PAGE_ALIGN(params.mmap_size +
259				    (params.mmap & ~PAGE_MASK)));
260
261	init_screen_info();
262}
263
264static int __init register_gop_device(void)
265{
266	void *pd;
267
268	if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
269		return 0;
270
271	pd = platform_device_register_data(NULL, "efi-framebuffer", 0,
272					   &screen_info, sizeof(screen_info));
273	return PTR_ERR_OR_ZERO(pd);
274}
275subsys_initcall(register_gop_device);