[PATCH v6 08/12] usb: dbc: handle endpoint stall

[Lu Baolu <baolu.lu@linux.intel.com>]

In case of endpoint stall, software is able to detect the situation
by reading DCCTRL.HIT or DCCTRL.HOT bits. DbC follows the normal USB
framework to handle endpoint stall. When software detects endpoint
stall situation, it should wait until endpoint is recovered before
read or write oprations.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/usb/early/xhci-dbc.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
index c81df40..344d93e 100644
--- a/drivers/usb/early/xhci-dbc.c
+++ b/drivers/usb/early/xhci-dbc.c
@@ -1163,6 +1163,37 @@ static int xdbc_wait_until_dbc_configured(void)
 	return -ETIMEDOUT;
 }
 
+static int xdbc_wait_until_epstall_cleared(bool read)
+{
+	int timeout = 0;
+
+	if (read) {
+		do {
+			if (!(readl(&xdbcp->xdbc_reg->control) & CTRL_HIT)) {
+				xdbcp->in_ep_state = EP_RUNNING;
+
+				return 0;
+			}
+
+			xdbcp->in_ep_state = EP_HALTED;
+			xdbc_udelay(10);
+		} while (timeout++ < XDBC_LOOPS);
+	} else {
+		do {
+			if (!(readl(&xdbcp->xdbc_reg->control) & CTRL_HOT)) {
+				xdbcp->out_ep_state = EP_RUNNING;
+
+				return 0;
+			}
+
+			xdbcp->out_ep_state = EP_HALTED;
+			xdbc_udelay(10);
+		} while (timeout++ < XDBC_LOOPS);
+	}
+
+	return -ETIMEDOUT;
+}
+
 static int xdbc_bulk_transfer(void *data, int size, int loops, bool read)
 {
 	u64 addr;
@@ -1182,6 +1213,11 @@ static int xdbc_bulk_transfer(void *data, int size, int loops, bool read)
 		return -EPERM;
 	}
 
+	if (xdbc_wait_until_epstall_cleared(read)) {
+		xdbc_trace("%s: endpoint not ready\n", __func__);
+		return -EPERM;
+	}
+
 	ring = (read ? &xdbcp->in_ring : &xdbcp->out_ring);
 	trb = ring->enqueue;
 	cycle = ring->cycle_state;
-- 
2.1.4