Types of memory that the SDRAM controller supports are DDR2/DDR3
and capacities of up to 2GiB. This commit adds emulation support
of the Allwinner R40 SDRAM controller.
This driver only support 256M, 512M and 1024M memory now.
Signed-off-by: qianfan Zhao <qianfanguijin@163.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
