I am using two SDIO controller with zedboard, one is routing through EMIO. It is said in the zynq TRM manual that EMIO only support 25MHz SDIO frequence. Therefore, I reduced the SDIO clk frequence to 25MHz.
But the u-boot wouldn't boot, the messages are as follow, anyone know why uboot is related to the SDIO clock frequence?
U-Boot 2013.10 (Apr 12 2014 - 19:25:33)
Memory: ECC disabled
DRAM: 512 MiB
MMC: zynq_sdhci: 0
SF: Detected S25FL256S_64K with page size 256 Bytes, erase size 64 KiB, total 32 MiB
*** Warning - bad CRC, using default environment
In: serial
Out: serial
Err: serial
Net: Gem.e000b000
Hit any key to stop autoboot: 0
Controller never released inhibit bit(s).
Controller never released inhibit bit(s).
Controller never released inhibit bit(s).
Controller never released inhibit bit(s).
Controller never released inhibit bit(s).
Controller never released inhibit bit(s).
Controller never released inhibit bit(s).
Device: zynq_sdhci
Manufacturer ID: ff
OEM: ff00
Name: ????
Tran Speed: 0
Rd Block Len: 1
SD version 2.0
High Capacity: Yes
Capacity: 0 Bytes
Bus Width: 1-bit
Controller never released inhibit bit(s).
** Bad device mmc 0 **
Copying Linux from SD to RAM...
Controller never released inhibit bit(s).
** Bad device mmc 0 **