[PATCH RESEND] xhci: Keep interrupt disabled in initialization until host is running.

Prashanth K
2023-10-09T10:40:44Z

From: Hongyu Xie <xy521521@gmail.com>

[ Upstream commit a808925075fb750804a60ff0710614466c396db4 ]

irq is disabled in xhci_quiesce(called by xhci_halt, with bit:2 cleared
in USBCMD register), but xhci_run(called by usb_add_hcd) re-enable it.
It's possible that you will receive thousands of interrupt requests
after initialization for 2.0 roothub. And you will get a lot of
warning like, "xHCI dying, ignoring interrupt. Shouldn't IRQs be
disabled?". This amount of interrupt requests will cause the entire
system to freeze.
This problem was first found on a device with ASM2142 host controller
on it.

[tidy up old code while moving it, reword header -Mathias]

Cc: stable@kernel.org
Signed-off-by: Hongyu Xie <xiehongyu1@kylinos.cn>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220623111945.1557702-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org> # 5.15
Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
---
drivers/usb/host/xhci.c | 34 +++++++++++++++++++++-------------
1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 541fe4d..7ee747e 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -607,8 +607,27 @@ static int xhci_init(struct usb_hcd *hcd)

static int xhci_run_finished(struct xhci_hcd *xhci)
{
+ unsigned long flags;
+ u32 temp;
+
+ /*
+ * Enable interrupts before starting the host (xhci 4.2 and 5.5.2).
+ * Protect the short window before host is running with a lock
+ */
+ spin_lock_irqsave(&xhci->lock, flags);
+
+ xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Enable interrupts");
+ temp = readl(&xhci->op_regs->command);
+ temp |= (CMD_EIE);
+ writel(temp, &xhci->op_regs->command);
+
+ xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Enable primary interrupter");
+ temp = readl(&xhci->ir_set->irq_pending);
+ writel(ER_IRQ_ENABLE(temp), &xhci->ir_set->irq_pending);
+
if (xhci_start(xhci)) {
xhci_halt(xhci);
+ spin_unlock_irqrestore(&xhci->lock, flags);
return -ENODEV;
}
xhci->shared_hcd->state = HC_STATE_RUNNING;
@@ -619,6 +638,8 @@ static int xhci_run_finished(struct xhci_hcd *xhci)

xhci_dbg_trace(xhci, trace_xhci_dbg_init,
"Finished xhci_run for USB3 roothub");
+
+ spin_unlock_irqrestore(&xhci->lock, flags);
return 0;
}

@@ -667,19 +688,6 @@ int xhci_run(struct usb_hcd *hcd)
temp |= (xhci->imod_interval / 250) & ER_IRQ_INTERVAL_MASK;
writel(temp, &xhci->ir_set->irq_control);

- /* Set the HCD state before we enable the irqs */
- temp = readl(&xhci->op_regs->command);
- temp |= (CMD_EIE);
- xhci_dbg_trace(xhci, trace_xhci_dbg_init,
- "// Enable interrupts, cmd = 0x%x.", temp);
- writel(temp, &xhci->op_regs->command);
-
- temp = readl(&xhci->ir_set->irq_pending);
- xhci_dbg_trace(xhci, trace_xhci_dbg_init,
- "// Enabling event ring interrupter %p by writing 0x%x to irq_pending",
- xhci->ir_set, (unsigned int) ER_IRQ_ENABLE(temp));
- writel(ER_IRQ_ENABLE(temp), &xhci->ir_set->irq_pending);
-
if (xhci->quirks & XHCI_NEC_HOST) {
struct xhci_command *command;

--
2.7.4