Hi, On 31.08.2017 14:41, Adrian Hunter wrote: > On 31/08/17 12:38, Stefan Roese wrote: >> Hi Andy, Hi Adrian, >> >> On 04.07.2017 15:53, Andy Shevchenko wrote: >>> On Tue, 2017-07-04 at 14:53 +0200, Stefan Roese wrote: >>>> Hi, >>>> >>>> we are currently investigating, if its possible to connect a SDIO >>>> device (WLAN module) to the SD-card interface "SD3" of the BayTrail >>>> SoC instead of the SDIO interface "SD2". The BayTrail manual states, >>>> that the SDIO interface is capable of connecting SDIO devices. Is >>>> this also possible for the SD-card interface "SD3", even if its not >>>> explicitly mentioned in the manual? If not, why is this not possible? >>>> >>>> Any insight on this would be really helpful. >>> >>> Hmm... I have no documentation for SD/SDIO/eMMC for BayTrail except the >>> public one. Internally I found some charts that shows similarities >>> between two. So, taking that into consideration I would suggest to try >>> it out on real hardware (MinnowBoard MAX, for example), only impediment >>> I can see is the absence of support in the drivers in Linux OS. If you >>> need it only in U-Boot, you perhaps may fix it easily. >>> >>> P.S. Adrian on vacation. >> >> I hope your vacation was great! >> >> Sorry for getting back to this, but I would really like to get some >> more feedback on this. Perhaps Adrian has some additional comments >> about the SDIO usage of the SD interface (SD3 - PCI Device ID 0x0f16) >> on BayTrail. >> >> I'm now running latest mainline Linux on this board and am trying to >> get the Linux MMC / SDIO subsystem to just detect a device on this >> SD PCI interface. For this I have added quite a bit of debug code to >> the MMC / SDIO code to see, if any device is detected on the SDIO >> port. But all command queries return timeout as far as I can tell. > > I would usually interpret that to mean the SDIO card is not turned on. > >> Adrian, do you have some additional information, if this mode of >> operation is possible at all on this SD-card interface, even if >> its not explicitly mentioned in the BayTrail datasheet? > > I have used removable SDIO cards in SD slots before. It should work. A quick update with another question below: After getting back to this issue, I now have the SD-card detection working, if I boot into Linux using U-Boot as bootloader on this BayTrail based board. But when I boot via original BIOS, the card detection fails. While debugging, I found that one register differs in both setups: U-Boot: [ 2.374751] mmc0: sdhci: ============ SDHCI REGISTER DUMP =========== [ 2.374761] mmc0: sdhci: Sys addr: 0x00000000 | Version: 0x0000b502 [ 2.374768] mmc0: sdhci: Blk size: 0x00000000 | Blk cnt: 0x00000000 [ 2.374774] mmc0: sdhci: Argument: 0x00000000 | Trn mode: 0x00000000 [ 2.374781] mmc0: sdhci: Present: 0x1fff0000 | Host ctl: 0x00000000 [ 2.374787] mmc0: sdhci: Power: 0x00000000 | Blk gap: 0x00000000 [ 2.374793] mmc0: sdhci: Wake-up: 0x00000000 | Clock: 0x00000000 [ 2.374799] mmc0: sdhci: Timeout: 0x00000000 | Int stat: 0x00000000 [ 2.374806] mmc0: sdhci: Int enab: 0x00ff0003 | Sig enab: 0x00ff0003 [ 2.374812] mmc0: sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000 [ 2.374819] mmc0: sdhci: Caps: 0x076864b2 | Caps_1: 0x00000000 [ 2.374825] mmc0: sdhci: Cmd: 0x00000000 | Max curr: 0x00000000 [ 2.374831] mmc0: sdhci: Resp[0]: 0x00000000 | Resp[1]: 0x00000000 [ 2.374837] mmc0: sdhci: Resp[2]: 0x00000000 | Resp[3]: 0x00000000 [ 2.374842] mmc0: sdhci: Host ctl2: 0x00000000 [ 2.374849] mmc0: sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x00000000 [ 2.374853] mmc0: sdhci: ============================================ BIOS: [ 3.435179] mmc0: sdhci: ============ SDHCI REGISTER DUMP =========== [ 3.435485] mmc0: sdhci: Sys addr: 0x00000000 | Version: 0x0000b502 [ 3.435756] mmc0: sdhci: Blk size: 0x00000000 | Blk cnt: 0x00000000 [ 3.436066] mmc0: sdhci: Argument: 0x00000000 | Trn mode: 0x00000000 [ 3.436338] mmc0: sdhci: Present: 0x01ff0000 | Host ctl: 0x00000000 [ 3.436603] mmc0: sdhci: Power: 0x00000000 | Blk gap: 0x00000000 [ 3.436868] mmc0: sdhci: Wake-up: 0x00000000 | Clock: 0x00000000 [ 3.437166] mmc0: sdhci: Timeout: 0x00000000 | Int stat: 0x00000000 [ 3.437437] mmc0: sdhci: Int enab: 0x00ff0003 | Sig enab: 0x00ff0003 [ 3.437704] mmc0: sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000 [ 3.437969] mmc0: sdhci: Caps: 0x076864b2 | Caps_1: 0x00000000 [ 3.438266] mmc0: sdhci: Cmd: 0x00000000 | Max curr: 0x00000000 [ 3.438537] mmc0: sdhci: Resp[0]: 0x00000000 | Resp[1]: 0x00000000 [ 3.438802] mmc0: sdhci: Resp[2]: 0x00000000 | Resp[3]: 0x00000000 [ 3.439135] mmc0: sdhci: Host ctl2: 0x00000000 [ 3.439334] mmc0: sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x00000000 [ 3.439598] mmc0: sdhci: ============================================ As you can see, the "present" register (SDHCI_PRESENT_STATE at 0x24) is different. Its read-only - do you have any idea, why this register is set to the non-default value of 0x01ff0000 in the BIOS case? BTW: Its set to the default value of 0x1fff0000 for the eMMC controller in the BIOS case as well. So only the SD controller has this different value. Thanks, Stefan -- 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
