iMX6 SabreSD SPL Support

This patch is for SPL support for iMX6 SabreSD. The said patches has been tested to work on SD2 and SD3 port of the said board. It tested the non-spl version of uboot as well.

After applying the following patches, it will produces SPL and u-boot.img binary images. You should run the two commands below to store it in your SD or eMMC.

sudo dd if=SPL of=/dev/xxx bs=1K seek=1; sync
sudo dd if=u-boot.img of=/dev/xxx bs=1K seek=69

Changes (v2):
Merged the SPL support into the main board file
Remove the compilation warmings

Changes (v3):
Removed sp and gd
Use imx_ddr_size to set the ram_size

Changes (v4):
Add a separate board configuration file to enable SPL (mx6sabresd_spl_defconfig).

Mapped DCD data to mx6_mmdc_calibration, mx6dq_iomux_grp_regs, mx6dq_iomux_ddr_regs and mx6_ddr3_cfg data structures.

Read 11 and 12 bits of BOOT_CFG register to actually determine the active mmc port.

Changes (v5):
Use the default CONFIG_SPL_STACK
Add a macro #ifndef for CONFIG_SYS_TEXT_BASE to avoid compilation warning.

Changes (v6):
Use board_mmc_init for spl mmc initialization instead of adding spl_board_mmc_init function

Changes (v7):
Corrected the chip select value and now the DRAM showing a correct 1 GiB.

John Tobias (5):
imx6: add spl config for mx6sabresd
imx6: add data configuration file for SPL
kconfig: imx6: add SUPPORT_SPL
imx6: add spl in the header file
imx6: SPL support for iMX6 SabreSD

 arch/arm/Kconfig                              |   1 +
 board/freescale/mx6sabresd/mx6sabresd.c       | 186 +++++++++++++++++++++++++-
 board/freescale/mx6sabresd/mx6sabresd_spl.cfg |  58 ++++++++
 configs/mx6sabresd_spl_defconfig              |   5 +
 include/configs/mx6sabre_common.h             |   2 +
 include/configs/mx6sabresd.h                  |   6 +
 6 files changed, 256 insertions(+), 2 deletions(-)
 create mode 100644 board/freescale/mx6sabresd/mx6sabresd_spl.cfg
 create mode 100644 configs/mx6sabresd_spl_defconfig