[U-Boot] How to reduce SDcard speed in u-boot

[Marco Cavallini]

2015-04-03 16:26 GMT+02:00 Michael Trimarchi <michael at amarulasolutions.com>:
> Hi
>
> Increase the divisor of the clock
>
> MXC_CCM_CSCDR1_USDHC[X]_PODF_MASK
> MXC_CCM_CSCDR1_USDHC[X]_PODF_OFFSET
>
> I'm not sure because I have not a board and no time before Easter
> to open documentation ;)
>
> Michael
>



Hi Michael,
the register CCM_CSCDR1 did the trick, thank you.
Unfortunately on the buggy hardware I have the same problem (printed below).

=========

On the working board

> md.l 020c4024 1

> clocks
PLL_SYS         792 MHz
PLL_BUS         528 MHz
PLL_OTG         480 MHz
PLL_NET          50 MHz

IPG           66000 kHz
UART          80000 kHz
AHB          132000 kHz
AXI          198000 kHz
DDR          396000 kHz
USDHC1       198000 kHz
USDHC2       198000 kHz
USDHC3       198000 kHz
USDHC4       198000 kHz
EMI SLOW      99000 kHz
IPG PERCLK    66000 kHz

> run loadk
reading uImage
5157968 bytes read in 454 ms (10.8 MiB/s)

Increased divisor below:

> mw.l 020c4024 00790b00

> clocks
PLL_SYS         792 MHz
PLL_BUS         528 MHz
PLL_OTG         480 MHz
PLL_NET          50 MHz

IPG           66000 kHz
UART          80000 kHz
AHB          132000 kHz
AXI          198000 kHz
DDR          396000 kHz
USDHC1       198000 kHz
USDHC2       198000 kHz
USDHC3        49500 kHz  <-------
USDHC4       198000 kHz
EMI SLOW      99000 kHz
IPG PERCLK    66000 kHz

> run loadk
reading uImage
5157968 bytes read in 882 ms (5.6 MiB/s) <--- slower upload into memory

=========

On the buggy board : ERROR

> fatload mmc 0:1 0x12000000 uImage
reading uImage
Error reading cluster
** Unable to read file uImage **
> fatload mmc 0:1 0x12000000 uImage
** Can't read partition table on 0:0 **
** Invalid partition 1 **
> fatload mmc 0:1 0x12000000 uImage
** Can't read partition table on 0:0 **
** Invalid partition 1 **

Ciao
--
Marco