arch/x86: Remove EARLY_EBDA_INIT support

This is unused now.

Change-Id: Ie8bc1d6761d66c5e1dda40c34c940cdba90646d2
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36363
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Michael Niewöhner
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/arch/x86/Kconfig

@@ -148,15 +148,6 @@ config PRERAM_CBMEM_CONSOLE_SIZE
 	help
 	  Increase this value if preram cbmem console is getting truncated
 
-config EARLY_EBDA_INIT
-	bool
-	default n
-	help
-	  Initialize BIOS EBDA area early in romstage to allow bootloader to
-	  use this region for storing data which can be available across
-	  various stages. If user is selecting this option then its users
-	  responsibility to perform EBDA initialization call during romstage.
-
 config PC80_SYSTEM
 	bool
 	default y if ARCH_X86

src/arch/x86/Makefile.inc

@@ -226,7 +226,6 @@ romstage-$(CONFIG_HAVE_ACPI_RESUME) += acpi_s3.c
 romstage-$(CONFIG_C_ENVIRONMENT_BOOTBLOCK) += gdt_init.S
 romstage-y += cbmem.c
 romstage-y += cbfs_and_run.c
-romstage-$(CONFIG_EARLY_EBDA_INIT) += ebda.c
 romstage-$(CONFIG_IDT_IN_EVERY_STAGE) += exception.c
 romstage-$(CONFIG_IDT_IN_EVERY_STAGE) += idt.S
 romstage-y += memmove.c
@@ -261,7 +260,6 @@ postcar-generic-ccopts += -D__POSTCAR__
 postcar-$(CONFIG_HAVE_ACPI_RESUME) += acpi_s3.c
 postcar-y += gdt_init.S
 postcar-y += cbfs_and_run.c
-postcar-$(CONFIG_EARLY_EBDA_INIT) += ebda.c
 postcar-$(CONFIG_IDT_IN_EVERY_STAGE) += exception.c
 postcar-$(CONFIG_IDT_IN_EVERY_STAGE) += idt.S
 postcar-y += exit_car.S

src/arch/x86/ebda.c

@@ -24,58 +24,12 @@ static void *get_ebda_start(void)
 	return (void *)((uintptr_t)DEFAULT_EBDA_SEGMENT << 4);
 }
 
-static bool is_length_valid(size_t dlength)
-{
-	/* Check if input data length is > DEFAULT_EBDA_SIZE */
-	if (dlength > DEFAULT_EBDA_SIZE)
-		return false;
-
-	/* Valid data length */
-	return true;
-}
-
 /*
  * EBDA area is representing a 1KB memory area just below
  * the top of conventional memory (below 1MB)
  */
 
-/*
+static void setup_ebda(u32 low_memory_size, u16 ebda_segment, u16 ebda_size)
- * write_ebda_data is a wrapper function to write into EBDA area
- *
- * data = data to be written into EBDA area
- * length = input data size.
- */
-void write_ebda_data(const void *data, size_t length)
-{
-	void *ebda;
-
-	if (!is_length_valid(length))
-		die("Input data length is > EBDA default size (1KiB)!");
-
-	ebda = get_ebda_start();
-
-	memcpy(ebda, data, length);
-}
-
-/*
- * read_ebda_data is a wrapper function to read from EBDA area
- *
- * data = data read from EBDA area based on input size
- * length = read data size.
- */
-void read_ebda_data(void *data, size_t length)
-{
-	void *ebda;
-
-	if (!is_length_valid(length))
-		die("Input data length is > EBDA default size (1KiB)!");
-
-	ebda = get_ebda_start();
-
-	memcpy(data, ebda, length);
-}
-
-void setup_ebda(u32 low_memory_size, u16 ebda_segment, u16 ebda_size)
 {
 	u16 low_memory_kb;
 	u16 ebda_kb;

src/arch/x86/include/arch/ebda.h

@@ -27,27 +27,6 @@
 #define DEFAULT_EBDA_SEGMENT	0xF600
 #define DEFAULT_EBDA_SIZE	0x400
 
-void setup_ebda(u32 low_memory_size, u16 ebda_segment, u16 ebda_size);
 void setup_default_ebda(void);
 
-/*
- * This read/write API only allows and assumes
- * a single EBDA structure type for a platform.
- */
-
-/*
- * write_ebda_data is a wrapper function to write into EBDA area
- *
- * data = data to be written into EBDA area
- * length = input data size.
- */
-void write_ebda_data(const void *data, size_t length);
-/*
- * read_ebda_data is a wrapper function to read from EBDA area
- *
- * data = data read from EBDA area based on input size
- * length = read data size.
- */
-void read_ebda_data(void *data, size_t length);
-
 #endif

src/arch/x86/tables.c

@@ -194,41 +194,6 @@ static unsigned long write_smbios_table(unsigned long rom_table_end)
 #define FORWARDING_TABLE_ADDR ((uintptr_t)0x500)
 static uintptr_t forwarding_table = FORWARDING_TABLE_ADDR;
 
-/*
- * For EARLY_EBDA_INIT the BDA area will be wiped on the resume path which
- * has the forwarding table entry. Therefore, when tables are written an
- * entry is placed in cbmem that can be restored on OS resume to the proper
- * location.
- */
-static void stash_forwarding_table(uintptr_t addr, size_t sz)
-{
-	void *cbmem_addr = cbmem_add(CBMEM_ID_CBTABLE_FWD, sz);
-
-	if (cbmem_addr == NULL) {
-		printk(BIOS_ERR, "Unable to allocate CBMEM forwarding entry.\n");
-		return;
-	}
-
-	memcpy(cbmem_addr, (void *)addr, sz);
-}
-
-static void restore_forwarding_table(void *dest)
-{
-	const struct cbmem_entry *fwd_entry;
-
-	fwd_entry = cbmem_entry_find(CBMEM_ID_CBTABLE_FWD);
-
-	if (fwd_entry == NULL) {
-		printk(BIOS_ERR, "Unable to restore CBMEM forwarding entry.\n");
-		return;
-	}
-
-	memcpy(dest, cbmem_entry_start(fwd_entry), cbmem_entry_size(fwd_entry));
-}
-
-BOOT_STATE_INIT_ENTRY(BS_OS_RESUME, BS_ON_ENTRY,
-	restore_forwarding_table, (void *)FORWARDING_TABLE_ADDR);
-
 void arch_write_tables(uintptr_t coreboot_table)
 {
 	size_t sz;
@@ -250,8 +215,6 @@ void arch_write_tables(uintptr_t coreboot_table)
 
 	sz = write_coreboot_forwarding_table(forwarding_table, coreboot_table);
 
-	stash_forwarding_table(forwarding_table, sz);
-
 	forwarding_table += sz;
 	/* Align up to page boundary for historical consistency. */
 	forwarding_table = ALIGN_UP(forwarding_table, 4*KiB);

src/device/device.c

@@ -1165,13 +1165,8 @@ void dev_initialize(void)
 	printk(BIOS_INFO, "Initializing devices...\n");
 
 #if CONFIG(ARCH_X86)
-	/*
+	/* Ensure EBDA is prepared before Option ROMs. */
-	 * Initialize EBDA area in ramstage if early
+	setup_default_ebda();
-	 * initialization is not done.
-	 */
-	if (!CONFIG(EARLY_EBDA_INIT))
-		/* Ensure EBDA is prepared before Option ROMs. */
-		setup_default_ebda();
 #endif
 
 	/* First call the mainboard init. */