On 2017-12-22 21:38, Kalle Valo wrote:
silexcommon@xxxxxxxxx writes:
From: Alagu Sankar <alagusankar@xxxxxxxxxxxxxxx>
Some SD host controllers still need bounce buffers for SDIO data
transfers. While the transfers worked fine on x86 platforms,
this is found to be required for i.MX6 based systems.
Changes are similar to and derived from the ath6kl sdio driver.
Signed-off-by: Alagu Sankar <alagusankar@xxxxxxxxxxxxxxx>
Why is the bounce buffer needed exactly, what are the symptoms etc? To
me this sounds like an ugly workaround for a SDIO controller driver
bug.
We faced problems with i.MX6. The authentication frame sent by the
driver never reached the air. The host driver accepted the buffer, but
did not send out the packet to the sdio module. No errors reported
anywhere, but the buffer is not accepted due to alignment. The same
driver however works fine without bounce buffer on x86 platform with
stdhci drivers. To make it compliant with all host controllers, we
introduced the bounce buffers, similar to what was done in ath6kl_sdio
drivers.
