The Linux kernel driver sets the number of event segments and entries to 1 , while the initial import of the xhci code set that values to 3 for reasons unknown. While most controllers are fine with more event segments with more entries, there are standard-conformant controllers (ie. Renesas RCar xHCI) which only support 1 event segment.

Set the number of event segments and event entries back to 1 to allow such controllers to work with U-Boot xHCI stack. Note that the Renesas controller correctly indicates ERST Max = 1 in HCSPARAMS2[7:4] .

Signed-off-by: Marek Vasut marek.vasut+renesas@gmail.com Cc: Bin Meng bmeng.cn@gmail.com --- drivers/usb/host/xhci.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index a497d9d830..3377450fca 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1045,9 +1045,9 @@ struct xhci_scratchpad { * (1K bytes * 8bytes/bit) / (4*32 bits) = 64 segment entries in the table, * meaning 64 ring segments. * Initial allocated size of the ERST, in number of entries */ -#define ERST_NUM_SEGS 3 +#define ERST_NUM_SEGS 1 /* Initial number of event segment rings allocated */ -#define ERST_ENTRIES 3 +#define ERST_ENTRIES 1 /* Initial allocated size of the ERST, in number of entries */ #define ERST_SIZE 64 /* Poll every 60 seconds */