On 9/11/20 9:43 PM, twarren@nvidia.com wrote:
From: Tom Warren twarren@nvidia.com
This fixes the XHCI driver on T210 boards (TX1, Nano). I was seeing that Set_Address wasn't completing, returning with a Context Parameter error. Examining the slot context, etc. showed that the correct info was there in RAM. Once I set 'dcache off' globally, it started working. This patch was created to force the TRB, etc. allocation to be in non-cached memory, which resulted in XHCI working on Nano/TX1 w/o the need for a global dcache disable. Thierry Reding pointed to a similar fix he'd done for the rtl6189 driver.
Sending this to the list for comment, as this should have affected other XHCI implementations on other SoCs. Note that Tegra X1 (T210) has a 64-byte cache line size (64-bit ARMv8), and I do see the flush_cache/inval_cache ARM code being called via xhci_cache_flash/xhci_inval_cache.
Is cache management on tegra210 broken ? I've seen the same non-cached workaround in the DWMAC ethernet driver.