mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-16 17:58:23 +00:00
54 lines
1.8 KiB
Text
54 lines
1.8 KiB
Text
|
|
||
|
|
--------------------------------------------
|
||
|
|
SOCFPGA Documentation for U-Boot and SPL
|
||
|
|
--------------------------------------------
|
||
|
|
|
||
|
|
This README is about U-Boot and SPL support for Altera's ARM Cortex-A9MPCore
|
||
|
|
based SOCFPGA. To know more about the hardware itself, please refer to
|
||
|
|
www.altera.com.
|
||
|
|
|
||
|
|
|
||
|
|
--------------------------------------------
|
||
|
|
socfpga_dw_mmc
|
||
|
|
--------------------------------------------
|
||
|
|
Here are macro and detailed configuration required to enable DesignWare SDMMC
|
||
|
|
controller support within SOCFPGA
|
||
|
|
|
||
|
|
#define CONFIG_MMC
|
||
|
|
-> To enable the SD MMC framework support
|
||
|
|
|
||
|
|
#define CONFIG_SDMMC_BASE (SOCFPGA_SDMMC_ADDRESS)
|
||
|
|
-> The base address of CSR register for DesignWare SDMMC controller
|
||
|
|
|
||
|
|
#define CONFIG_GENERIC_MMC
|
||
|
|
-> Enable the generic MMC driver
|
||
|
|
|
||
|
|
#define CONFIG_SYS_MMC_MAX_BLK_COUNT 256
|
||
|
|
-> Using smaller max blk cnt to avoid flooding the limited stack in OCRAM
|
||
|
|
|
||
|
|
#define CONFIG_DWMMC
|
||
|
|
-> Enable the common DesignWare SDMMC controller framework
|
||
|
|
|
||
|
|
#define CONFIG_SOCFPGA_DWMMC
|
||
|
|
-> Enable the SOCFPGA specific driver for DesignWare SDMMC controller
|
||
|
|
|
||
|
|
#define CONFIG_SOCFPGA_DWMMC_FIFO_DEPTH 1024
|
||
|
|
-> The FIFO depth for SOCFPGA DesignWare SDMMC controller
|
||
|
|
|
||
|
|
#define CONFIG_SOCFPGA_DWMMC_DRVSEL 3
|
||
|
|
-> Phase-shifted clock of sdmmc_clk for controller to drive command and data to
|
||
|
|
the card to meet hold time requirements. SD clock is running at 50MHz and
|
||
|
|
drvsel is set to shift 135 degrees (3 * 45 degrees). With that, the hold time
|
||
|
|
is 135 / 360 * 20ns = 7.5ns.
|
||
|
|
|
||
|
|
#define CONFIG_SOCFPGA_DWMMC_SMPSEL 0
|
||
|
|
-> Phase-shifted clock of sdmmc_clk used to sample the command and data from
|
||
|
|
the card
|
||
|
|
|
||
|
|
#define CONFIG_SOCFPGA_DWMMC_BUS_WIDTH 4
|
||
|
|
-> Bus width of data line which either 1, 4 or 8 and based on board routing.
|
||
|
|
|
||
|
|
#define CONFIG_SOCFPGA_DWMMC_BUS_HZ 50000000
|
||
|
|
-> The clock rate to controller. Do note the controller have a wrapper which
|
||
|
|
divide the clock from PLL by 4.
|