[PATCH 12/15] xhci: Prevent queuing new commands if xhci is inaccessible

[Mathias Nyman <mathias.nyman@linux.intel.com>]

Refuse to queue a new command on the command ring if xHC is marked
inaccessible with the HCD_FLAG_HW_ACCESSIBLE.

HCD_FLAG_HW_ACCESSIBLE is set and cleared in suspend and resume.

Also print a warning if xhci is being suspended with commands
still pending on the command ring.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
---
 drivers/usb/host/xhci-ring.c | 6 ++++++
 drivers/usb/host/xhci.c      | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 608b6f3ec9f6..83209db29962 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -4332,6 +4332,7 @@ static int queue_command(struct xhci_hcd *xhci, struct xhci_command *cmd,
 			 u32 field3, u32 field4, bool command_must_succeed)
 {
 	int reserved_trbs = xhci->cmd_ring_reserved_trbs;
+	struct usb_hcd *hcd = xhci_to_hcd(xhci);
 	int ret;
 
 	if ((xhci->xhc_state & XHCI_STATE_DYING) ||
@@ -4341,6 +4342,11 @@ static int queue_command(struct xhci_hcd *xhci, struct xhci_command *cmd,
 		return -ESHUTDOWN;
 	}
 
+	if (!HCD_HW_ACCESSIBLE(hcd)) {
+		xhci_warn(xhci, "Can't queue command, xHC not accessible\n");
+		return -ESHUTDOWN;
+	}
+
 	if (!command_must_succeed)
 		reserved_trbs++;
 
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 0bf0446b4c87..0646fedf2042 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -992,6 +992,10 @@ int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup)
 	/* step 1: stop endpoint */
 	/* skipped assuming that port suspend has done */
 
+	/* Check if command ring is empty */
+	if (!list_empty(&xhci->cmd_list))
+		xhci_warn(xhci, "Suspending and stopping xHC with pending command!\n");
+
 	/* step 2: clear Run/Stop bit */
 	command = readl(&xhci->op_regs->command);
 	command &= ~CMD_RUN;
-- 
2.43.0