usb: host: xhci: use __ffs() instead of hardcoding shift (8d3709f3) · Commits · 戴 / test

__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 <balbi@ti.com> Signed-off-by:

Sarah Sharp <sarah.a.sharp@linux.intel.com>

drivers/usb/host/xhci.h

+1 −4

Original line number	Diff line number	Diff line
		@@ -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)

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