Hello dear experts,
I need your support and suggestions for a problem I have. We have custom boards with several versions based on ls1088a-rdb. In one of these versions, we have SD/eMMC connection switched via mux from cpld, designed on the same line. If I activate the eMMC line from cpld before powering on the device, I can successfully see it in the "/dev/mmcblk0" path when I type "fdisk -l" in the user space. But I want to use the SD card for booting and then activate the eMMC.
I tried this in user space and switched the eMMC line by sending a command to CPLD from the ls1088 UART3(/dev/ttyS2) line. However, when I say "fdisk -l" I don't see any active mmc lines. When I examine the kernel output with dmesg I get this error: "
/dev/mmcblk0: Can't open blockdev
mmcblk0: error -110 requesting status
mmcblk0: recovery failed!
My first question here is, is it possible to activate emmc after uboot and kernel initialization?
Second question is can I send data to CPLD via UART later during the flexbuild u-boot boot phase? UART1(ttyS0) is console, UART3 connected to CPLD. Is it possible to send data via UART3 line in U-boot?
