x86: Add support for the Simple Firmware Interface (SFI)

This provides a way of passing information to Linux without requiring the
full ACPI horror. Provide a rudimentary implementation sufficient to be
recognised and parsed by Linux.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

3 files changed, 160 insertions, 0 deletions

diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 0178fe1b88..70ad19b263 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -26,6 +26,7 @@ obj-y	+= pirq_routing.o
 obj-y	+= relocate.o
 obj-y += physmem.o
 obj-$(CONFIG_X86_RAMTEST) += ramtest.o
+obj-y += sfi.o
 obj-y	+= string.o
 obj-y	+= tables.o
 obj-$(CONFIG_SYS_X86_TSC_TIMER)	+= tsc_timer.o
diff --git a/arch/x86/lib/sfi.c b/arch/x86/lib/sfi.c
new file mode 100644
index 0000000000..3d3658088a
--- /dev/null
+++ b/arch/x86/lib/sfi.c
@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/*
+ * Intel Simple Firmware Interface (SFI)
+ *
+ * Yet another way to pass information to the Linux kernel.
+ *
+ * See https://simplefirmware.org/ for details
+ */
+
+#include <common.h>
+#include <cpu.h>
+#include <dm.h>
+#include <asm/cpu.h>
+#include <asm/ioapic.h>
+#include <asm/sfi.h>
+#include <asm/tables.h>
+#include <dm/uclass-internal.h>
+
+struct table_info {
+	u32 base;
+	int ptr;
+	u32 entry_start;
+	u64 table[SFI_TABLE_MAX_ENTRIES];
+	int count;
+};
+
+static void *get_entry_start(struct table_info *tab)
+{
+	if (tab->count == SFI_TABLE_MAX_ENTRIES)
+		return NULL;
+	tab->entry_start = tab->base + tab->ptr;
+	tab->table[tab->count] = tab->entry_start;
+	tab->entry_start += sizeof(struct sfi_table_header);
+
+	return (void *)tab->entry_start;
+}
+
+static void finish_table(struct table_info *tab, const char *sig, void *entry)
+{
+	struct sfi_table_header *hdr;
+
+	hdr = (struct sfi_table_header *)(tab->base + tab->ptr);
+	strcpy(hdr->sig, sig);
+	hdr->len = sizeof(*hdr) + ((ulong)entry - tab->entry_start);
+	hdr->rev = 1;
+	strncpy(hdr->oem_id, "U-Boot", SFI_OEM_ID_SIZE);
+	strncpy(hdr->oem_table_id, "Table v1", SFI_OEM_TABLE_ID_SIZE);
+	hdr->csum = 0;
+	hdr->csum = table_compute_checksum(hdr, hdr->len);
+	tab->ptr += hdr->len;
+	tab->ptr = ALIGN(tab->ptr, 16);
+	tab->count++;
+}
+
+static int sfi_write_system_header(struct table_info *tab)
+{
+	u64 *entry = get_entry_start(tab);
+	int i;
+
+	if (!entry)
+		return -ENOSPC;
+
+	for (i = 0; i < tab->count; i++)
+		*entry++ = tab->table[i];
+	finish_table(tab, SFI_SIG_SYST, entry);
+
+	return 0;
+}
+
+static int sfi_write_cpus(struct table_info *tab)
+{
+	struct sfi_cpu_table_entry *entry = get_entry_start(tab);
+	struct udevice *dev;
+	int count = 0;
+
+	if (!entry)
+		return -ENOSPC;
+
+	for (uclass_find_first_device(UCLASS_CPU, &dev);
+	     dev;
+	     uclass_find_next_device(&dev)) {
+		struct cpu_platdata *plat = dev_get_parent_platdata(dev);
+
+		if (!device_active(dev))
+			continue;
+		entry->apic_id = plat->cpu_id;
+		entry++;
+		count++;
+	}
+
+	/* Omit the table if there is only one CPU */
+	if (count > 1)
+		finish_table(tab, SFI_SIG_CPUS, entry);
+
+	return 0;
+}
+
+static int sfi_write_apic(struct table_info *tab)
+{
+	struct sfi_apic_table_entry *entry = get_entry_start(tab);
+
+	if (!entry)
+		return -ENOSPC;
+
+	entry->phys_addr = IO_APIC_ADDR;
+	entry++;
+	finish_table(tab, SFI_SIG_APIC, entry);
+
+	return 0;
+}
+
+static int sfi_write_xsdt(struct table_info *tab)
+{
+	struct sfi_xsdt_header *entry = get_entry_start(tab);
+
+	if (!entry)
+		return -ENOSPC;
+
+	entry->oem_revision = 1;
+	entry->creator_id = 1;
+	entry->creator_revision = 1;
+	entry++;
+	finish_table(tab, SFI_SIG_XSDT, entry);
+
+	return 0;
+}
+
+u32 write_sfi_table(u32 base)
+{
+	struct table_info table;
+
+	table.base = base;
+	table.ptr = 0;
+	table.count = 0;
+	sfi_write_cpus(&table);
+	sfi_write_apic(&table);
+
+	/*
+	 * The SFI specification marks the XSDT table as option, but Linux 4.0
+	 * crashes on start-up when it is not provided.
+	 */
+	sfi_write_xsdt(&table);
+
+	/* Finally, write out the system header which points to the others */
+	sfi_write_system_header(&table);
+
+	return base + table.ptr;
+}
diff --git a/arch/x86/lib/tables.c b/arch/x86/lib/tables.c
index 0836e1e426..8031201a49 100644
--- a/arch/x86/lib/tables.c
+++ b/arch/x86/lib/tables.c
@@ -5,6 +5,7 @@
  */
 
 #include <common.h>
+#include <asm/sfi.h>
 #include <asm/tables.h>
 
 u8 table_compute_checksum(void *v, int len)
@@ -27,4 +28,8 @@ void write_tables(void)
 	rom_table_end = write_pirq_routing_table(rom_table_end);
 	rom_table_end = ALIGN(rom_table_end, 1024);
 #endif
+#ifdef CONFIG_GENERATE_SFI_TABLE
+	rom_table_end = write_sfi_table(rom_table_end);
+	rom_table_end = ALIGN(rom_table_end, 1024);
+#endif
 }