xhci: Keep interrupt disabled in initialization until host is running.

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>

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 9ac56e9ffc645f68d8c7e328371f83be50915501..cb99bed5f755e07aca0fa52e61b9f92f8ffd1cf9 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -611,15 +611,37 @@ 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->cmd_ring_state = CMD_RING_STATE_RUNNING;
 
        if (xhci->quirks & XHCI_NEC_HOST)
                xhci_ring_cmd_db(xhci);
 
+       spin_unlock_irqrestore(&xhci->lock, flags);
+
        return 0;
 }
 
@@ -668,19 +690,6 @@ 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;