6 files changed, 62 insertions, 2 deletions
diff --git a/payloads/libpayload/Config.in b/payloads/libpayload/Config.in
index 4d4876182e..92c89abeb8 100644
--- a/payloads/libpayload/Config.in
+++ b/payloads/libpayload/Config.in
@@ -495,6 +495,12 @@ config USB_XHCI
 	  Select this option if you want to use USB 3.0
 	  NOTE: This option is not (fully) implemented yet
 
+config USB_XHCI_MTK_QUIRK
+	bool "Support for USB xHCI controllers on MTK SoC"
+	depends on USB_XHCI
+	help
+	  Select this option if you want to use USB 3.0 on MTK platform.
+
 config USB_DWC2
 	bool "Support for USB DesignWare HCD controllers"
 	depends on USB && !USB_HID
diff --git a/payloads/libpayload/drivers/usb/xhci.c b/payloads/libpayload/drivers/usb/xhci.c
index 26dcdbe4de..89930e06df 100644
--- a/payloads/libpayload/drivers/usb/xhci.c
+++ b/payloads/libpayload/drivers/usb/xhci.c
@@ -370,6 +370,8 @@ xhci_reinit (hci_t *controller)
 	xhci->ev_ring_table[0].seg_base_hi = 0;
 	xhci->ev_ring_table[0].seg_size = EVENT_RING_SIZE;
 
+	/* pass event ring table to hardware */
+	wmb();
 	/* Initialize primary interrupter */
 	xhci->hcrreg->intrrs[0].erstsz = 1;
 	xhci_update_event_dq(xhci);
@@ -510,6 +512,7 @@ xhci_enqueue_trb(transfer_ring_t *const tr)
 		xhci_spew("Handling LINK pointer\n");
 		const int tc = TRB_GET(TC, tr->cur);
 		TRB_SET(CH, tr->cur, chain);
+		wmb();
 		TRB_SET(C, tr->cur, tr->pcs);
 		tr->cur = phys_to_virt(tr->cur->ptr_low);
 		if (tc)
@@ -535,7 +538,7 @@ xhci_enqueue_td(transfer_ring_t *const tr, const int ep, const size_t mps,
 			cur_length = length;
 			packets = 0;
 			length = 0;
-		} else {
+		} else if (!IS_ENABLED(CONFIG_LP_XHCI_MTK_QUIRK)) {
 			packets -= (residue + cur_length) / mps;
 			residue = (residue + cur_length) % mps;
 			length -= cur_length;
@@ -548,6 +551,18 @@ xhci_enqueue_td(transfer_ring_t *const tr, const int ep, const size_t mps,
 		TRB_SET(TDS, trb, MIN(TRB_MAX_TD_SIZE, packets));
 		TRB_SET(CH, trb, 1);
 
+		if (length && IS_ENABLED(CONFIG_LP_XHCI_MTK_QUIRK)) {
+			/*
+			 * For MTK's xHCI controller, TDS defines a number of
+			 * packets that remain to be transferred for a TD after
+			 * processing all Max packets in all previous TRBs, that
+			 * means don't include the current TRB's.
+			 */
+			packets -= (residue + cur_length) / mps;
+			residue = (residue + cur_length) % mps;
+			length -= cur_length;
+		}
+
 		/* Check for first, data stage TRB */
 		if (!trb_count && ep == 1) {
 			TRB_SET(DIR, trb, dir);
diff --git a/payloads/libpayload/drivers/usb/xhci_commands.c b/payloads/libpayload/drivers/usb/xhci_commands.c
index 009a69c812..845a34dee7 100644
--- a/payloads/libpayload/drivers/usb/xhci_commands.c
+++ b/payloads/libpayload/drivers/usb/xhci_commands.c
@@ -47,6 +47,8 @@ xhci_post_command(xhci_t *const xhci)
 	TRB_SET(C, xhci->cr.cur, xhci->cr.pcs);
 	++xhci->cr.cur;
 
+	/* pass command trb to hardware */
+	wmb();
 	/* Ring the doorbell */
 	xhci->dbreg[0] = 0;
 
diff --git a/payloads/libpayload/drivers/usb/xhci_devconf.c b/payloads/libpayload/drivers/usb/xhci_devconf.c
index 012f610287..5b5bb5e800 100644
--- a/payloads/libpayload/drivers/usb/xhci_devconf.c
+++ b/payloads/libpayload/drivers/usb/xhci_devconf.c
@@ -313,6 +313,16 @@ xhci_finish_ep_config(const endpoint_t *const ep, inputctx_t *const ic)
 	EC_SET(AVRTRB,	epctx, avrtrb);
 	EC_SET(MXESIT,  epctx, EC_GET(MPS, epctx) * EC_GET(MBS, epctx));
 
+	if (IS_ENABLED(CONFIG_LP_USB_XHCI_MTK_QUIRK)) {
+		/* The MTK xHCI defines some extra SW parameters which are
+		 * put into reserved DWs in Slot and Endpoint Contexts for
+		 * synchronous endpoints. But for non-isochronous transfers,
+		 * it is enough to set the following two fields to 1, and others
+		 * are set to 0.
+		 */
+		EC_SET(BPKTS, epctx, 1);
+		EC_SET(BBM, epctx, 1);
+	}
 	return 0;
 }
 
diff --git a/payloads/libpayload/drivers/usb/xhci_private.h b/payloads/libpayload/drivers/usb/xhci_private.h
index 3861858b44..f01a37f842 100644
--- a/payloads/libpayload/drivers/usb/xhci_private.h
+++ b/payloads/libpayload/drivers/usb/xhci_private.h
@@ -33,6 +33,8 @@
 
 //#define USB_DEBUG
 #include <usb/usb.h>
+#include <arch/barrier.h>
+#include <kconfig.h>
 
 //#define XHCI_DUMPS
 #define xhci_debug(fmt, args...) usb_debug("%s: " fmt, __func__, ## args)
@@ -242,6 +244,13 @@ typedef volatile struct slotctx {
 #define EC_MXESIT_FIELD		f5		/* MXESIT - Max ESIT Payload */
 #define EC_MXESIT_START		16
 #define EC_MXESIT_LEN		16
+#define EC_BPKTS_FIELD		rsvd[0]		/* BPKTS - packets tx in scheduled uframe */
+#define EC_BPKTS_START		0
+#define EC_BPKTS_LEN		6
+#define EC_BBM_FIELD		rsvd[0]		/* BBM - burst mode for scheduling */
+#define EC_BBM_START		11
+#define EC_BBM_LEN		1
+
 #define EC_MASK(tok)		MASK(EC_##tok##_START, EC_##tok##_LEN)
 #define EC_GET(tok, ec)		(((ec)->EC_##tok##_FIELD & EC_MASK(tok)) \
 				 >> EC_##tok##_START)
diff --git a/payloads/libpayload/drivers/usb/xhci_rh.c b/payloads/libpayload/drivers/usb/xhci_rh.c
index fa118fe460..bcb01ace98 100644
--- a/payloads/libpayload/drivers/usb/xhci_rh.c
+++ b/payloads/libpayload/drivers/usb/xhci_rh.c
@@ -119,6 +119,24 @@ xhci_rh_reset_port(usbdev_t *const dev, const int port)
 	return 0;
 }
 
+static int
+xhci_rh_enable_port(usbdev_t *const dev, int port)
+{
+	if (IS_ENABLED(CONFIG_LP_USB_XHCI_MTK_QUIRK)) {
+		xhci_t *const xhci = XHCI_INST(dev->controller);
+		volatile u32 *const portsc =
+			&xhci->opreg->prs[port - 1].portsc;
+
+		/*
+		 * Before sending commands to a port, the Port Power in
+		 * PORTSC register should be enabled on MTK's xHCI.
+		 */
+		*portsc = (*portsc & PORTSC_RW_MASK) | PORTSC_PP;
+	}
+	return 0;
+}
+
+
 static const generic_hub_ops_t xhci_rh_ops = {
 	.hub_status_changed	= xhci_rh_hub_status_changed,
 	.port_status_changed	= xhci_rh_port_status_changed,
@@ -126,7 +144,7 @@ static const generic_hub_ops_t xhci_rh_ops = {
 	.port_in_reset		= xhci_rh_port_in_reset,
 	.port_enabled		= xhci_rh_port_enabled,
 	.port_speed		= xhci_rh_port_speed,
-	.enable_port		= NULL,
+	.enable_port		= xhci_rh_enable_port,
 	.disable_port		= NULL,
 	.start_port_reset	= NULL,
 	.reset_port		= xhci_rh_reset_port,