On 30 September 2017 at 17:39, Bernd Edlinger <bernd.edlinger@xxxxxxxxxx> wrote: > > Needs external logic to multiplex the clock signal, > which is controlled by a GPIO output pin. > > Only the selected SD card receives the clock, > while the other SD card's clock is forced to LOW. > DATA and CMD lines can be connected to both SD cards. > > On warm-start UBOOT should use a sequence of > CMD12 and CMD7 with RCA=0 to force any active SD card > to stop transmission and release the DATA bus. I doubt that is sufficient to support multiple slots. Sometimes the mmc core needs to perform a sequence of operations towards *one* host/card and that must be done in guaranteed manner, to that no other operations are performed for another card/host in-between. Perhaps if you are lucky you may get something that is very fragile to work, but in the end I think the core needs to play along. Moreover, dw_mmc has recently removed its multiple slot support - simply because the complexity wasn't worth it. Unless Jaehoon have changed his mind, I am not going to pick this up. [...] Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
