thunderbolt: Get rid of usb4_usb3_port_actual_link_rate()

It turns out there is no need to use the actual link rate when
reclaiming bandwidth for USB 3.x. The reason is that we use consumed
bandwidth which is coming from xHCI when releasing bandwidth (for
example for DisplayPort tunneling) and this can be anything between
1000 Mb/s to maximum, so when reclaiming we can just bump it up back to
maximum instead of actual link rate (which is always <= maximum).

This allows us to get rid of couple of unnecessary lines of code.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/tb.h

@@ -1283,7 +1283,6 @@ int usb4_port_retimer_nvm_read(struct tb_port *port, u8 index,
 			       unsigned int address, void *buf, size_t size);
 
 int usb4_usb3_port_max_link_rate(struct tb_port *port);
-int usb4_usb3_port_actual_link_rate(struct tb_port *port);
 int usb4_usb3_port_allocated_bandwidth(struct tb_port *port, int *upstream_bw,
 				       int *downstream_bw);
 int usb4_usb3_port_allocate_bandwidth(struct tb_port *port, int *upstream_bw,

drivers/thunderbolt/tb_regs.h

@@ -484,9 +484,6 @@ struct tb_regs_port_header {
 #define ADP_USB3_CS_3				0x03
 #define ADP_USB3_CS_3_SCALE_MASK		GENMASK(5, 0)
 #define ADP_USB3_CS_4				0x04
-#define ADP_USB3_CS_4_ALR_MASK			GENMASK(6, 0)
-#define ADP_USB3_CS_4_ALR_20G			0x1
-#define ADP_USB3_CS_4_ULV			BIT(7)
 #define ADP_USB3_CS_4_MSLR_MASK			GENMASK(18, 12)
 #define ADP_USB3_CS_4_MSLR_SHIFT		12
 #define ADP_USB3_CS_4_MSLR_20G			0x1

drivers/thunderbolt/tunnel.c

@@ -1790,17 +1790,10 @@ static void tb_usb3_reclaim_available_bandwidth(struct tb_tunnel *tunnel,
 {
 	int ret, max_rate, allocate_up, allocate_down;
 
-	ret = usb4_usb3_port_actual_link_rate(tunnel->src_port);
+	ret = tb_usb3_max_link_rate(tunnel->dst_port, tunnel->src_port);
 	if (ret < 0) {
-		tb_tunnel_warn(tunnel, "failed to read actual link rate\n");
+		tb_tunnel_warn(tunnel, "failed to read maximum link rate\n");
 		return;
-	} else if (!ret) {
-		/* Use maximum link rate if the link valid is not set */
-		ret = tb_usb3_max_link_rate(tunnel->dst_port, tunnel->src_port);
-		if (ret < 0) {
-			tb_tunnel_warn(tunnel, "failed to read maximum link rate\n");
-			return;
-		}
 	}
 
 	/*

drivers/thunderbolt/usb4.c

@@ -1946,35 +1946,6 @@ int usb4_usb3_port_max_link_rate(struct tb_port *port)
 	return usb4_usb3_port_max_bandwidth(port, ret);
 }
 
-/**
- * usb4_usb3_port_actual_link_rate() - Established USB3 link rate
- * @port: USB3 adapter port
- *
- * Return actual established link rate of a USB3 adapter in Mb/s. If the
- * link is not up returns %0 and negative errno in case of failure.
- */
-int usb4_usb3_port_actual_link_rate(struct tb_port *port)
-{
-	int ret, lr;
-	u32 val;
-
-	if (!tb_port_is_usb3_down(port) && !tb_port_is_usb3_up(port))
-		return -EINVAL;
-
-	ret = tb_port_read(port, &val, TB_CFG_PORT,
-			   port->cap_adap + ADP_USB3_CS_4, 1);
-	if (ret)
-		return ret;
-
-	if (!(val & ADP_USB3_CS_4_ULV))
-		return 0;
-
-	lr = val & ADP_USB3_CS_4_ALR_MASK;
-	ret = lr == ADP_USB3_CS_4_ALR_20G ? 20000 : 10000;
-
-	return usb4_usb3_port_max_bandwidth(port, ret);
-}
-
 static int usb4_usb3_port_cm_request(struct tb_port *port, bool request)
 {
 	int ret;