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>

arch/x86/Kconfig

@@ -393,6 +393,20 @@ config GENERATE_PIRQ_TABLE
 	  It specifies the interrupt router information as well how all the PCI
 	  devices' interrupt pins are wired to PIRQs.
 
+config GENERATE_SFI_TABLE
+	bool "Generate a SFI (Simple Firmware Interface) table"
+	help
+	  The Simple Firmware Interface (SFI) provides a lightweight method
+	  for platform firmware to pass information to the operating system
+	  via static tables in memory.  Kernel SFI support is required to
+	  boot on SFI-only platforms.  If you have ACPI tables then these are
+	  used instead.
+
+	  U-Boot writes this table in write_sfi_table() just before booting
+	  the OS.
+
+	  For more information, see http://simplefirmware.org
+
 endmenu
 
 config MAX_PIRQ_LINKS

arch/x86/include/asm/sfi.h

@@ -0,0 +1,137 @@
+/*
+ * Copyright(c) 2009 Intel Corporation. All rights reserved.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+	BSD-3-Clause
+ */
+
+#ifndef _LINUX_SFI_H
+#define _LINUX_SFI_H
+
+#include <errno.h>
+#include <linux/types.h>
+
+/* Table signatures reserved by the SFI specification */
+#define SFI_SIG_SYST		"SYST"
+#define SFI_SIG_FREQ		"FREQ"
+#define SFI_SIG_CPUS		"CPUS"
+#define SFI_SIG_MTMR		"MTMR"
+#define SFI_SIG_MRTC		"MRTC"
+#define SFI_SIG_MMAP		"MMAP"
+#define SFI_SIG_APIC		"APIC"
+#define SFI_SIG_XSDT		"XSDT"
+#define SFI_SIG_WAKE		"WAKE"
+#define SFI_SIG_DEVS		"DEVS"
+#define SFI_SIG_GPIO		"GPIO"
+
+#define SFI_SIGNATURE_SIZE	4
+#define SFI_OEM_ID_SIZE		6
+#define SFI_OEM_TABLE_ID_SIZE	8
+
+#define SFI_NAME_LEN		16
+#define SFI_TABLE_MAX_ENTRIES	16
+
+#define SFI_GET_NUM_ENTRIES(ptable, entry_type) \
+	((ptable->header.len - sizeof(struct sfi_table_header)) / \
+	(sizeof(entry_type)))
+/*
+ * Table structures must be byte-packed to match the SFI specification,
+ * as they are provided by the BIOS.
+ */
+struct __packed sfi_table_header {
+	char	sig[SFI_SIGNATURE_SIZE];
+	u32	len;
+	u8	rev;
+	u8	csum;
+	char	oem_id[SFI_OEM_ID_SIZE];
+	char	oem_table_id[SFI_OEM_TABLE_ID_SIZE];
+};
+
+struct __packed sfi_table_simple {
+	struct sfi_table_header		header;
+	u64				pentry[1];
+};
+
+/* Comply with UEFI spec 2.1 */
+struct __packed sfi_mem_entry {
+	u32	type;
+	u64	phys_start;
+	u64	virt_start;
+	u64	pages;
+	u64	attrib;
+};
+
+struct __packed sfi_cpu_table_entry {
+	u32	apic_id;
+};
+
+struct __packed sfi_cstate_table_entry {
+	u32	hint;		/* MWAIT hint */
+	u32	latency;	/* latency in ms */
+};
+
+struct __packed sfi_apic_table_entry {
+	u64	phys_addr;	/* phy base addr for APIC reg */
+};
+
+struct __packed sfi_freq_table_entry {
+	u32	freq_mhz;	/* in MHZ */
+	u32	latency;	/* transition latency in ms */
+	u32	ctrl_val;	/* value to write to PERF_CTL */
+};
+
+struct __packed sfi_wake_table_entry {
+	u64	phys_addr;	/* pointer to where the wake vector locates */
+};
+
+struct __packed sfi_timer_table_entry {
+	u64	phys_addr;	/* phy base addr for the timer */
+	u32	freq_hz;	/* in HZ */
+	u32	irq;
+};
+
+struct __packed sfi_rtc_table_entry {
+	u64	phys_addr;	/* phy base addr for the RTC */
+	u32	irq;
+};
+
+struct __packed sfi_device_table_entry {
+	u8	type;		/* bus type, I2C, SPI or ...*/
+	u8	host_num;	/* attached to host 0, 1...*/
+	u16	addr;
+	u8	irq;
+	u32	max_freq;
+	char	name[SFI_NAME_LEN];
+};
+
+enum {
+	SFI_DEV_TYPE_SPI	= 0,
+	SFI_DEV_TYPE_I2C,
+	SFI_DEV_TYPE_UART,
+	SFI_DEV_TYPE_HSI,
+	SFI_DEV_TYPE_IPC,
+	SFI_DEV_TYPE_SD,
+};
+
+struct __packed sfi_gpio_table_entry {
+	char	controller_name[SFI_NAME_LEN];
+	u16	pin_no;
+	char	pin_name[SFI_NAME_LEN];
+};
+
+struct sfi_xsdt_header {
+	uint32_t oem_revision;
+	uint32_t creator_id;
+	uint32_t creator_revision;
+};
+
+typedef int (*sfi_table_handler) (struct sfi_table_header *table);
+
+/**
+ * write_sfi_table() - Write Simple Firmware Interface tables
+ *
+ * @base:	Address to write table to
+ * @return address to use for the next table
+ */
+u32 write_sfi_table(u32 base);
+
+#endif /*_LINUX_SFI_H */

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

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;
+}

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
 }