powerpc : spi flash : Support to start from eSPI with SPL

This patch introduces SPL to enable a loader stub that being loaded by
the code from the internal on-chip ROM. It loads the final uboot image
into DDR, then jump to it to begin execution.

The SPL's size is sizeable, the maximum size must not exceed the size of L2
SRAM. It initializes the DDR through SPD code, and copys final uboot image
to DDR. So there are two stage uboot images:
	* spl_boot, 96KB size. The env variables are copied to L2 SRAM, so that
	ddr spd code can get the interleaving mode setting in env. It loads
	final uboot image from offset 96KB.
	* final uboot image, size is variable depends on the functions enabled.

Signed-off-by: Ying Zhang <b40530@freescale.com>
Acked-by: York Sun <yorksun@freescale.com>

drivers/mtd/spi/Makefile

@@ -11,6 +11,7 @@ LIB	:= $(obj)libspi_flash.o
 
 ifdef CONFIG_SPL_BUILD
 COBJS-$(CONFIG_SPL_SPI_LOAD)	+= spi_spl_load.o
+COBJS-$(CONFIG_SPL_SPI_BOOT)	+= fsl_espi_spl.o
 endif
 
 COBJS-$(CONFIG_SPI_FLASH)	+= spi_flash.o

drivers/mtd/spi/fsl_espi_spl.c

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2013 Freescale Semiconductor, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ */
+
+#include <common.h>
+#include <spi_flash.h>
+#include <malloc.h>
+
+#define ESPI_BOOT_IMAGE_SIZE	0x48
+#define ESPI_BOOT_IMAGE_ADDR	0x50
+#define CONFIG_CFG_DATA_SECTOR	0
+
+/*
+ * The main entry for SPI booting. It's necessary that SDRAM is already
+ * configured and available since this code loads the main U-Boot image
+ * from SPI into SDRAM and starts it from there.
+ */
+void spi_boot(void)
+{
+	void (*uboot)(void) __noreturn;
+	u32 offset, code_len;
+	unsigned char *buf = NULL;
+	struct spi_flash *flash;
+
+	flash = spi_flash_probe(CONFIG_ENV_SPI_BUS, CONFIG_ENV_SPI_CS,
+			CONFIG_ENV_SPI_MAX_HZ, CONFIG_ENV_SPI_MODE);
+	if (flash == NULL) {
+		puts("\nspi_flash_probe failed");
+		hang();
+	}
+
+	/*
+	* Load U-Boot image from SPI flash into RAM
+	*/
+	buf = malloc(flash->page_size);
+	if (buf == NULL) {
+		puts("\nmalloc failed");
+		hang();
+	}
+	memset(buf, 0, flash->page_size);
+
+	spi_flash_read(flash, CONFIG_CFG_DATA_SECTOR,
+		       flash->page_size, (void *)buf);
+	offset = *(u32 *)(buf + ESPI_BOOT_IMAGE_ADDR);
+	/* Skip spl code */
+	offset += CONFIG_SYS_SPI_FLASH_U_BOOT_OFFS;
+	/* Get the code size from offset 0x48 */
+	code_len = *(u32 *)(buf + ESPI_BOOT_IMAGE_SIZE);
+	/* Skip spl code */
+	code_len = code_len - CONFIG_SPL_MAX_SIZE;
+	/* copy code to DDR */
+	spi_flash_read(flash, offset, code_len,
+		       (void *)CONFIG_SYS_SPI_FLASH_U_BOOT_DST);
+	/*
+	* Jump to U-Boot image
+	*/
+	flush_cache(CONFIG_SYS_SPI_FLASH_U_BOOT_DST, code_len);
+	uboot = (void *)CONFIG_SYS_SPI_FLASH_U_BOOT_START;
+	(*uboot)();
+}

drivers/mtd/spi/spi_flash.c

@@ -555,12 +555,14 @@ struct spi_flash *spi_flash_probe(unsigned int bus, unsigned int cs,
 		goto err_manufacturer_probe;
 	}
 #endif
+#ifndef CONFIG_SPL_BUILD
 	printf("SF: Detected %s with page size ", flash->name);
 	print_size(flash->sector_size, ", total ");
 	print_size(flash->size, "");
 	if (flash->memory_map)
 		printf(", mapped at %p", flash->memory_map);
 	puts("\n");
+#endif
 #ifndef CONFIG_SPI_FLASH_BAR
 	if (flash->size > SPI_FLASH_16MB_BOUN) {
 		puts("SF: Warning - Only lower 16MiB accessible,");