xhci: Don't pass struct xhci_hcd pointer to xhci_link_seg()

It's only used to dig out if we need to set a chain flag for specific
hosts. Pass the flag directly as a parameter instead.

No functional changes.

xhci_link_seg() is also used by DbC code, this change helps decoupling
xhci and DbC.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20200723144530.9992-4-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-mem.c

@@ -96,8 +96,9 @@ static void xhci_free_segments_for_ring(struct xhci_hcd *xhci,
  * DMA address of the next segment.  The caller needs to set any Link TRB
  * related flags, such as End TRB, Toggle Cycle, and no snoop.
  */
-static void xhci_link_segments(struct xhci_hcd *xhci, struct xhci_segment *prev,
-		struct xhci_segment *next, enum xhci_ring_type type)
+static void xhci_link_segments(struct xhci_segment *prev,
+			       struct xhci_segment *next,
+			       enum xhci_ring_type type, bool chain_links)
 {
 	u32 val;
 
@@ -112,11 +113,7 @@ static void xhci_link_segments(struct xhci_hcd *xhci, struct xhci_segment *prev,
 		val = le32_to_cpu(prev->trbs[TRBS_PER_SEGMENT-1].link.control);
 		val &= ~TRB_TYPE_BITMASK;
 		val |= TRB_TYPE(TRB_LINK);
-		/* Always set the chain bit with 0.95 hardware */
-		/* Set chain bit for isoc rings on AMD 0.96 host */
-		if (xhci_link_trb_quirk(xhci) ||
-				(type == TYPE_ISOC &&
-				 (xhci->quirks & XHCI_AMD_0x96_HOST)))
+		if (chain_links)
 			val |= TRB_CHAIN;
 		prev->trbs[TRBS_PER_SEGMENT-1].link.control = cpu_to_le32(val);
 	}
@@ -131,13 +128,19 @@ static void xhci_link_rings(struct xhci_hcd *xhci, struct xhci_ring *ring,
 		unsigned int num_segs)
 {
 	struct xhci_segment *next;
+	bool chain_links;
 
 	if (!ring || !first || !last)
 		return;
 
+	/* Set chain bit for 0.95 hosts, and for isoc rings on AMD 0.96 host */
+	chain_links = !!(xhci_link_trb_quirk(xhci) ||
+			 (ring->type == TYPE_ISOC &&
+			  (xhci->quirks & XHCI_AMD_0x96_HOST)));
+
 	next = ring->enq_seg->next;
-	xhci_link_segments(xhci, ring->enq_seg, first, ring->type);
-	xhci_link_segments(xhci, last, next, ring->type);
+	xhci_link_segments(ring->enq_seg, first, ring->type, chain_links);
+	xhci_link_segments(last, next, ring->type, chain_links);
 	ring->num_segs += num_segs;
 	ring->num_trbs_free += (TRBS_PER_SEGMENT - 1) * num_segs;
 
@@ -321,6 +324,12 @@ static int xhci_alloc_segments_for_ring(struct xhci_hcd *xhci,
 		enum xhci_ring_type type, unsigned int max_packet, gfp_t flags)
 {
 	struct xhci_segment *prev;
+	bool chain_links;
+
+	/* Set chain bit for 0.95 hosts, and for isoc rings on AMD 0.96 host */
+	chain_links = !!(xhci_link_trb_quirk(xhci) ||
+			 (type == TYPE_ISOC &&
+			  (xhci->quirks & XHCI_AMD_0x96_HOST)));
 
 	prev = xhci_segment_alloc(xhci, cycle_state, max_packet, flags);
 	if (!prev)
@@ -341,12 +350,12 @@ static int xhci_alloc_segments_for_ring(struct xhci_hcd *xhci,
 			}
 			return -ENOMEM;
 		}
-		xhci_link_segments(xhci, prev, next, type);
+		xhci_link_segments(prev, next, type, chain_links);
 
 		prev = next;
 		num_segs--;
 	}
-	xhci_link_segments(xhci, prev, *first, type);
+	xhci_link_segments(prev, *first, type, chain_links);
 	*last = prev;
 
 	return 0;