AM1808 SDIO

Suresh K59789

Intellectual 875 points

Other Parts Discussed in Thread: AM1808, WL1271, OMAP-L138

Hi,

One of my Customers has the following problem regarding the AM1808.

Please look into this. I will direct my Customer to this Forum for further discussions, if required.

Thanks in advance.

We are adding support for SDIO driver for Atheros ar6K2 chipset in our solution on AM1808exp platform.

We have found that the status register of host controller (MMCSD) on AM1808 chipset shows response Timeout or Response CRC errors (TOUTRS,CRCRS) in case we issue CMD52 or CMD53.

If we ignore these errors the card is detected by Atheros SDIO stack but it sometimes work and sometimes fails due to some data transfer.

I need to know: is this controller is tested with any SDIO card? and is there any thing special need to be done for SDIO commands support?

over 15 years ago

0 Gaurav Agarwal over 15 years ago

TI__Expert 3425 points

Suresh,

One instance of SDIO usage has been with AM18 platform connected to a TI WL1271 module over SDIO and using a linux standard SDIO driver on top of the “DaVinci-PSP-SDK-03.20.00.13”.

Can you please provide more details on the setup? OS? Have you tried more than one chipset?

Regards,
Gaurav

0 Sarfraz Ahmed over 15 years ago in reply to Gaurav Agarwal

Prodigy 10 points

Gaurav,

We are using Atheros AR6002 chipset (http://www.silexamerica.com/products/wireless_modules/sx-sdcag.html) based SDIO cards. We are using MMCSD0 host controller connected to on-board SD slot on AM1808exp rev1 board and using Nucleus RTOS with Atheros SDIO stack for WIFI connectivity.

We have looked at mmc driver (Davinci_mmc) and unified patches of DaVinci PSP 03.20.00.14 and DaVinci PSP 03.20.00.13 PSP. The unified patches don't seem to have any specific difference related to mmc/sd. We have reviewed mmc driver (Davinci_mmc.c ) and tried the register configurations (which were found bit different) in our driver but it did not work for SDIO. Our driver works perfectly on different SD and MMC cards.

Also the driver feature information at following links state that "SDIO - WLAN" driver is not supported in this release. Is WLAN or SDIO tested on MMCSD0?

http://processors.wiki.ti.com/index.php/DaVinci_PSP_03.20.00.14_Release_Notes
http://processors.wiki.ti.com/index.php/DaVinci_PSP_03.20.00.14_Device_Driver_Features_and_Performance_Guide#MMC.2FSD_Driver

We are experiencing following issues

1) Response CRC errors on few commands during card detection.

2) Some times SDIO Card interrupt is getting missed although SDIO and controller interrupts are enabled. This is basically transfer completion interrupt from SDIO card. Although the data transfer seems to be getting completed correctly (as per register status) but we still do not receive SDIO interrupt. Interrupt missing usually happens during AP scanning or association. Before this step we correctly receive interrupts.

Regards,

Sarfraz Ahmed

0 Gaurav Agarwal over 15 years ago in reply to Sarfraz Ahmed

TI__Expert 3425 points

Sarfraz,

This looks like a Driver/PSP issue. I am moving this post to the Linux forum so that it can reach the right experts.

Regards,
Gaurav

0 Sekhar Nori over 15 years ago in reply to Gaurav Agarwal

TI__Expert 6385 points

Sarfraz,

I recently tested SDIO on OMAP-L138 using a Marvell Libertas based SDIO WLAN card, but did not see the kind of issues you point out.

If it is of any help, please have a look at this patch which adds SDIO support to the davinci_mmc.c driver:

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=f9db92cb8084c756890ddf953e9329588c59e8e8

Thanks,

Sekhar

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AM1808 SDIO