From 8d3709f3dd41769338cc383bec23673fd1ce34e7 Mon Sep 17 00:00:00 2001 From: Felipe Balbi Date: Fri, 27 Jan 2012 16:19:15 +0200 Subject: usb: host: xhci: use __ffs() instead of hardcoding shift __ffs() can tell us which is the SEGMENT_SHIFT value to be used. This will prevent problems when users are too fast and don't pay attention to the need of fixing the Shift after changing TRBS_PER_SEGMENT. Signed-off-by: Felipe Balbi Signed-off-by: Sarah Sharp --- drivers/usb/host/xhci.h | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'drivers/usb/host/xhci.h') diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 0f4936956103..9a7138c29030 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1223,10 +1223,7 @@ union xhci_trb { /* Allow two commands + a link TRB, along with any reserved command TRBs */ #define MAX_RSVD_CMD_TRBS (TRBS_PER_SEGMENT - 3) #define SEGMENT_SIZE (TRBS_PER_SEGMENT*16) -/* SEGMENT_SHIFT should be log2(SEGMENT_SIZE). - * Change this if you change TRBS_PER_SEGMENT! - */ -#define SEGMENT_SHIFT 10 +#define SEGMENT_SHIFT (__ffs(SEGMENT_SIZE)) /* TRB buffer pointers can't cross 64KB boundaries */ #define TRB_MAX_BUFF_SHIFT 16 #define TRB_MAX_BUFF_SIZE (1 << TRB_MAX_BUFF_SHIFT) -- cgit v1.2.3