Hi,
I have two questions about the working modes of MMC/SDIO, Now we are trying an wifi module with the sdio port of AM335x.
1) Event Handling
TRM says that there are two methods, interrupt & polling, for handling the events of SDIO/MMC port.
BTW, according to omap_hsmmc.c in kernel, I think interrupt mode is used by default.
And looks like no option for polling mode.
Please let me know if my understanding is correct.
2) DATA Transfer Mode
From our PSP web-page, we can see following information. For data transfer, DMA or polled mode is supported.
I'm using LInux EZSDK. How can I check which mode is being used?
In the case of USB, there is the CPPI DMA option in the kernel config. So when the CPPI DMA is chosen, then USB works at DMA mode.
Introduction
AM335x has 3 instances MMC/SD/SDIO host controller, which provides an interface between microprocessor and either MMC, SD memory cards, or SDIO cards. The current version of the user guide talks about the MMC/SD controller. The MMC/SD driver is implemented as a block driver on top of host controller as a HSMMC controller driver and supports SD, SD High Speed and SDHC cards. This driver only supports for 4 bit modes(no SPI mode, 1/8 Bit). Both DMA & polled mode of data transfer is supported.
Thanks,
Devin
