x86: Prepare configuration tables in dedicated high memory region

Currently when CONFIG_SEABIOS is on, U-Boot allocates configuration
tables via normal malloc(). To simplify, use a dedicated memory
region which is reserved on the stack before relocation for this
purpose. Add functions for reserve and malloc.

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

arch/x86/Kconfig

@@ -531,6 +531,20 @@ config SEABIOS
 
 	  Check http://www.seabios.org/SeaBIOS for details.
 
+config HIGH_TABLE_SIZE
+	hex "Size of configuration tables which reside in high memory"
+	default 0x10000
+	depends on SEABIOS
+	help
+	  SeaBIOS itself resides in E seg and F seg, where U-Boot puts all
+	  configuration tables like PIRQ/MP/ACPI. To avoid conflicts, U-Boot
+	  puts a copy of configuration tables in high memory region which
+	  is reserved on the stack before relocation. The region size is
+	  determined by this option.
+
+	  Increse it if the default size does not fit the board's needs.
+	  This is most likely due to a large ACPI DSDT table is used.
+
 source "arch/x86/lib/efi/Kconfig"
 
 endmenu

arch/x86/include/asm/coreboot_tables.h

@@ -294,6 +294,25 @@ struct cbmem_entry {
 #define CBMEM_ID_CONSOLE		0x434f4e53
 #define CBMEM_ID_NONE			0x00000000
 
+/**
+ * high_table_reserve() - reserve configuration table in high memory
+ *
+ * This reserves configuration table in high memory.
+ *
+ * @return:	always 0
+ */
+int high_table_reserve(void);
+
+/**
+ * high_table_malloc() - allocate configuration table in high memory
+ *
+ * This allocates configuration table in high memory.
+ *
+ * @bytes:	size of configuration table to be allocated
+ * @return:	pointer to configuration table in high memory
+ */
+void *high_table_malloc(size_t bytes);
+
 /**
  * write_coreboot_table() - write coreboot table
  *

arch/x86/include/asm/global_data.h

@@ -93,6 +93,10 @@ struct arch_global_data {
 	char *mrc_output;
 	unsigned int mrc_output_len;
 	ulong table;			/* Table pointer from previous loader */
+#ifdef CONFIG_SEABIOS
+	u32 high_table_ptr;
+	u32 high_table_limit;
+#endif
 };
 
 #endif

arch/x86/lib/coreboot_table.c

@@ -9,6 +9,37 @@
 #include <asm/coreboot_tables.h>
 #include <asm/e820.h>
 
+DECLARE_GLOBAL_DATA_PTR;
+
+int high_table_reserve(void)
+{
+	/* adjust stack pointer to reserve space for configuration tables */
+	gd->arch.high_table_limit = gd->start_addr_sp;
+	gd->start_addr_sp -= CONFIG_HIGH_TABLE_SIZE;
+	gd->arch.high_table_ptr = gd->start_addr_sp;
+
+	/* clear the memory */
+	memset((void *)gd->arch.high_table_ptr, 0, CONFIG_HIGH_TABLE_SIZE);
+
+	gd->start_addr_sp &= ~0xf;
+
+	return 0;
+}
+
+void *high_table_malloc(size_t bytes)
+{
+	u32 new_ptr;
+	void *ptr;
+
+	new_ptr = gd->arch.high_table_ptr + bytes;
+	if (new_ptr >= gd->arch.high_table_limit)
+		return NULL;
+	ptr = (void *)gd->arch.high_table_ptr;
+	gd->arch.high_table_ptr = new_ptr;
+
+	return ptr;
+}
+
 /**
  * cb_table_init() - initialize a coreboot table header
  *