1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Extensible Firmware Interface
  4 *
  5 * Based on Extensible Firmware Interface Specification version 2.4
  6 *
  7 * Copyright (C) 2013 - 2015 Linaro Ltd.
  8 */
  9
 10#define pr_fmt(fmt)	"efi: " fmt
 11
 12#include <linux/efi.h>
 13#include <linux/fwnode.h>
 14#include <linux/init.h>
 15#include <linux/memblock.h>
 16#include <linux/mm_types.h>
 17#include <linux/of.h>
 18#include <linux/of_address.h>
 19#include <linux/of_fdt.h>
 20#include <linux/platform_device.h>
 21#include <linux/screen_info.h>
 22
 23#include <asm/efi.h>
 24
 25static int __init is_memory(efi_memory_desc_t *md)
 26{
 27	if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
 28		return 1;
 29	return 0;
 30}
 31
 32/*
 33 * Translate a EFI virtual address into a physical address: this is necessary,
 34 * as some data members of the EFI system table are virtually remapped after
 35 * SetVirtualAddressMap() has been called.
 36 */
 37static phys_addr_t __init efi_to_phys(unsigned long addr)
 38{
 39	efi_memory_desc_t *md;
 40
 41	for_each_efi_memory_desc(md) {
 42		if (!(md->attribute & EFI_MEMORY_RUNTIME))
 43			continue;
 44		if (md->virt_addr == 0)
 45			/* no virtual mapping has been installed by the stub */
 46			break;
 47		if (md->virt_addr <= addr &&
 48		    (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
 49			return md->phys_addr + addr - md->virt_addr;
 50	}
 51	return addr;
 52}
 53
 54static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;
 55static __initdata unsigned long cpu_state_table = EFI_INVALID_TABLE_ADDR;
 56
 57static const efi_config_table_type_t arch_tables[] __initconst = {
 58	{LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, &screen_info_table},
 59	{LINUX_EFI_ARM_CPU_STATE_TABLE_GUID, &cpu_state_table},
 60	{}
 61};
 62
 63static void __init init_screen_info(void)
 64{
 65	struct screen_info *si;
 66
 67	if (IS_ENABLED(CONFIG_ARM) &&
 68	    screen_info_table != EFI_INVALID_TABLE_ADDR) {
 69		si = early_memremap_ro(screen_info_table, sizeof(*si));
 70		if (!si) {
 71			pr_err("Could not map screen_info config table\n");
 72			return;
 73		}
 74		screen_info = *si;
 75		early_memunmap(si, sizeof(*si));
 76
 77		/* dummycon on ARM needs non-zero values for columns/lines */
 78		screen_info.orig_video_cols = 80;
 79		screen_info.orig_video_lines = 25;
 80	}
 81
 82	if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
 83	    memblock_is_map_memory(screen_info.lfb_base))
 84		memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
 85}
 86
 87static int __init uefi_init(u64 efi_system_table)
 88{
 89	efi_config_table_t *config_tables;
 90	efi_system_table_t *systab;
 91	size_t table_size;
 92	int retval;
 93
 94	systab = early_memremap_ro(efi_system_table, sizeof(efi_system_table_t));
 95	if (systab == NULL) {
 96		pr_warn("Unable to map EFI system table.\n");
 97		return -ENOMEM;
 98	}
 99
100	set_bit(EFI_BOOT, &efi.flags);
101	if (IS_ENABLED(CONFIG_64BIT))
102		set_bit(EFI_64BIT, &efi.flags);
103
104	retval = efi_systab_check_header(&systab->hdr, 2);
105	if (retval)
106		goto out;
107
108	efi.runtime = systab->runtime;
109	efi.runtime_version = systab->hdr.revision;
110
111	efi_systab_report_header(&systab->hdr, efi_to_phys(systab->fw_vendor));
112
113	table_size = sizeof(efi_config_table_t) * systab->nr_tables;
114	config_tables = early_memremap_ro(efi_to_phys(systab->tables),
115					  table_size);
116	if (config_tables == NULL) {
117		pr_warn("Unable to map EFI config table array.\n");
118		retval = -ENOMEM;
119		goto out;
120	}
121	retval = efi_config_parse_tables(config_tables, systab->nr_tables,
122					 IS_ENABLED(CONFIG_ARM) ? arch_tables
123								: NULL);
124
125	early_memunmap(config_tables, table_size);
126out:
127	early_memunmap(systab, sizeof(efi_system_table_t));
128	return retval;
129}
130
131/*
132 * Return true for regions that can be used as System RAM.
133 */
134static __init int is_usable_memory(efi_memory_desc_t *md)
135{
136	switch (md->type) {
137	case EFI_LOADER_CODE:
138	case EFI_LOADER_DATA:
139	case EFI_ACPI_RECLAIM_MEMORY:
140	case EFI_BOOT_SERVICES_CODE:
141	case EFI_BOOT_SERVICES_DATA:
142	case EFI_CONVENTIONAL_MEMORY:
143	case EFI_PERSISTENT_MEMORY:
144		/*
145		 * Special purpose memory is 'soft reserved', which means it
146		 * is set aside initially, but can be hotplugged back in or
147		 * be assigned to the dax driver after boot.
148		 */
149		if (efi_soft_reserve_enabled() &&
150		    (md->attribute & EFI_MEMORY_SP))
151			return false;
152
153		/*
154		 * According to the spec, these regions are no longer reserved
155		 * after calling ExitBootServices(). However, we can only use
156		 * them as System RAM if they can be mapped writeback cacheable.
157		 */
158		return (md->attribute & EFI_MEMORY_WB);
159	default:
160		break;
161	}
162	return false;
163}
164
165static __init void reserve_regions(void)
166{
167	efi_memory_desc_t *md;
168	u64 paddr, npages, size;
169
170	if (efi_enabled(EFI_DBG))
171		pr_info("Processing EFI memory map:\n");
172
173	/*
174	 * Discard memblocks discovered so far: if there are any at this
175	 * point, they originate from memory nodes in the DT, and UEFI
176	 * uses its own memory map instead.
177	 */
178	memblock_dump_all();
179	memblock_remove(0, PHYS_ADDR_MAX);
180
181	for_each_efi_memory_desc(md) {
182		paddr = md->phys_addr;
183		npages = md->num_pages;
184
185		if (efi_enabled(EFI_DBG)) {
186			char buf[64];
187
188			pr_info("  0x%012llx-0x%012llx %s\n",
189				paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
190				efi_md_typeattr_format(buf, sizeof(buf), md));
191		}
192
193		memrange_efi_to_native(&paddr, &npages);
194		size = npages << PAGE_SHIFT;
195
196		if (is_memory(md)) {
197			early_init_dt_add_memory_arch(paddr, size);
198
199			if (!is_usable_memory(md))
200				memblock_mark_nomap(paddr, size);
201
202			/* keep ACPI reclaim memory intact for kexec etc. */
203			if (md->type == EFI_ACPI_RECLAIM_MEMORY)
204				memblock_reserve(paddr, size);
205		}
206	}
207}
208
209void __init efi_init(void)
210{
211	struct efi_memory_map_data data;
212	u64 efi_system_table;
213
214	/* Grab UEFI information placed in FDT by stub */
215	efi_system_table = efi_get_fdt_params(&data);
216	if (!efi_system_table)
217		return;
218
219	if (efi_memmap_init_early(&data) < 0) {
220		/*
221		* If we are booting via UEFI, the UEFI memory map is the only
222		* description of memory we have, so there is little point in
223		* proceeding if we cannot access it.
224		*/
225		panic("Unable to map EFI memory map.\n");
226	}
227
228	WARN(efi.memmap.desc_version != 1,
229	     "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
230	      efi.memmap.desc_version);
231
232	if (uefi_init(efi_system_table) < 0) {
233		efi_memmap_unmap();
234		return;
235	}
236
237	reserve_regions();
238	efi_esrt_init();
239
240	memblock_reserve(data.phys_map & PAGE_MASK,
241			 PAGE_ALIGN(data.size + (data.phys_map & ~PAGE_MASK)));
242
243	init_screen_info();
244
245#ifdef CONFIG_ARM
246	/* ARM does not permit early mappings to persist across paging_init() */
247	efi_memmap_unmap();
248
249	if (cpu_state_table != EFI_INVALID_TABLE_ADDR) {
250		struct efi_arm_entry_state *state;
251		bool dump_state = true;
252
253		state = early_memremap_ro(cpu_state_table,
254					  sizeof(struct efi_arm_entry_state));
255		if (state == NULL) {
256			pr_warn("Unable to map CPU entry state table.\n");
257			return;
258		}
259
260		if ((state->sctlr_before_ebs & 1) == 0)
261			pr_warn(FW_BUG "EFI stub was entered with MMU and Dcache disabled, please fix your firmware!\n");
262		else if ((state->sctlr_after_ebs & 1) == 0)
263			pr_warn(FW_BUG "ExitBootServices() returned with MMU and Dcache disabled, please fix your firmware!\n");
264		else
265			dump_state = false;
266
267		if (dump_state || efi_enabled(EFI_DBG)) {
268			pr_info("CPSR at EFI stub entry        : 0x%08x\n", state->cpsr_before_ebs);
269			pr_info("SCTLR at EFI stub entry       : 0x%08x\n", state->sctlr_before_ebs);
270			pr_info("CPSR after ExitBootServices() : 0x%08x\n", state->cpsr_after_ebs);
271			pr_info("SCTLR after ExitBootServices(): 0x%08x\n", state->sctlr_after_ebs);
272		}
273		early_memunmap(state, sizeof(struct efi_arm_entry_state));
274	}
275#endif
276}
277
278static bool efifb_overlaps_pci_range(const struct of_pci_range *range)
279{
280	u64 fb_base = screen_info.lfb_base;
281
282	if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
283		fb_base |= (u64)(unsigned long)screen_info.ext_lfb_base << 32;
284
285	return fb_base >= range->cpu_addr &&
286	       fb_base < (range->cpu_addr + range->size);
287}
288
289static struct device_node *find_pci_overlap_node(void)
290{
291	struct device_node *np;
292
293	for_each_node_by_type(np, "pci") {
294		struct of_pci_range_parser parser;
295		struct of_pci_range range;
296		int err;
297
298		err = of_pci_range_parser_init(&parser, np);
299		if (err) {
300			pr_warn("of_pci_range_parser_init() failed: %d\n", err);
301			continue;
302		}
303
304		for_each_of_pci_range(&parser, &range)
305			if (efifb_overlaps_pci_range(&range))
306				return np;
307	}
308	return NULL;
309}
310
311/*
312 * If the efifb framebuffer is backed by a PCI graphics controller, we have
313 * to ensure that this relation is expressed using a device link when
314 * running in DT mode, or the probe order may be reversed, resulting in a
315 * resource reservation conflict on the memory window that the efifb
316 * framebuffer steals from the PCIe host bridge.
317 */
318static int efifb_add_links(const struct fwnode_handle *fwnode,
319			   struct device *dev)
320{
321	struct device_node *sup_np;
322	struct device *sup_dev;
323
324	sup_np = find_pci_overlap_node();
325
326	/*
327	 * If there's no PCI graphics controller backing the efifb, we are
328	 * done here.
329	 */
330	if (!sup_np)
331		return 0;
332
333	sup_dev = get_dev_from_fwnode(&sup_np->fwnode);
334	of_node_put(sup_np);
335
336	/*
337	 * Return -ENODEV if the PCI graphics controller device hasn't been
338	 * registered yet.  This ensures that efifb isn't allowed to probe
339	 * and this function is retried again when new devices are
340	 * registered.
341	 */
342	if (!sup_dev)
343		return -ENODEV;
344
345	/*
346	 * If this fails, retrying this function at a later point won't
347	 * change anything. So, don't return an error after this.
348	 */
349	if (!device_link_add(dev, sup_dev, fw_devlink_get_flags()))
350		dev_warn(dev, "device_link_add() failed\n");
351
352	put_device(sup_dev);
353
354	return 0;
355}
356
357static const struct fwnode_operations efifb_fwnode_ops = {
358	.add_links = efifb_add_links,
359};
360
361static struct fwnode_handle efifb_fwnode = {
362	.ops = &efifb_fwnode_ops,
363};
364
365static int __init register_gop_device(void)
366{
367	struct platform_device *pd;
368	int err;
369
370	if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
371		return 0;
372
373	pd = platform_device_alloc("efi-framebuffer", 0);
374	if (!pd)
375		return -ENOMEM;
376
377	if (IS_ENABLED(CONFIG_PCI))
378		pd->dev.fwnode = &efifb_fwnode;
379
380	err = platform_device_add_data(pd, &screen_info, sizeof(screen_info));
381	if (err)
382		return err;
383
384	return platform_device_add(pd);
385}
386subsys_initcall(register_gop_device);