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usb: xhci: Implement xhci_handshake_check_state() helper

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In some situations where xhci removal happens parallel to xhci_handshake,
we encounter a scenario where the xhci_handshake can't succeed, and it
polls until timeout.

If xhci_handshake runs until timeout it can on some platforms result in
a long wait which might lead to a watchdog timeout.

Add a helper that checks xhci status during the handshake, and exits if
set state is entered. Use this helper in places where xhci_handshake is
called unlocked and has a long timeout. For example  xhci command timeout
and xhci reset.

[commit message and code comment rewording -Mathias]

Signed-off-by: Udipto Goswami <quic_ugoswami@quicinc.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20231019102924.2797346-18-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Udipto Goswami 2023-10-19 13:29:22 +03:00 committed by Greg Kroah-Hartman
parent 47f503cf5f
commit 6ccb83d6c4
3 changed files with 30 additions and 3 deletions
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5
drivers/usb/host/xhci-ring.c
View File

@ -450,8 +450,9 @@ static int xhci_abort_cmd_ring(struct xhci_hcd *xhci, unsigned long flags)
* In the future we should distinguish between -ENODEV and -ETIMEDOUT
* and try to recover a -ETIMEDOUT with a host controller reset.
*/
ret = xhci_handshake(&xhci->op_regs->cmd_ring,
CMD_RING_RUNNING, 0, 5 * 1000 * 1000);
ret = xhci_handshake_check_state(xhci, &xhci->op_regs->cmd_ring,
CMD_RING_RUNNING, 0, 5 * 1000 * 1000,
XHCI_STATE_REMOVING);
if (ret < 0) {
xhci_err(xhci, "Abort failed to stop command ring: %d\n", ret);
xhci_halt(xhci);

26
drivers/usb/host/xhci.c
View File

@ -81,6 +81,29 @@ int xhci_handshake(void __iomem *ptr, u32 mask, u32 done, u64 timeout_us)
return ret;
}
/*
* xhci_handshake_check_state - same as xhci_handshake but takes an additional
* exit_state parameter, and bails out with an error immediately when xhc_state
* has exit_state flag set.
*/
int xhci_handshake_check_state(struct xhci_hcd *xhci, void __iomem *ptr,
u32 mask, u32 done, int usec, unsigned int exit_state)
{
u32 result;
int ret;
ret = readl_poll_timeout_atomic(ptr, result,
(result & mask) == done ||
result == U32_MAX ||
xhci->xhc_state & exit_state,
1, usec);
if (result == U32_MAX || xhci->xhc_state & exit_state)
return -ENODEV;
return ret;
}
/*
* Disable interrupts and begin the xHCI halting process.
*/
@ -201,7 +224,8 @@ int xhci_reset(struct xhci_hcd *xhci, u64 timeout_us)
if (xhci->quirks & XHCI_INTEL_HOST)
udelay(1000);
ret = xhci_handshake(&xhci->op_regs->command, CMD_RESET, 0, timeout_us);
ret = xhci_handshake_check_state(xhci, &xhci->op_regs->command,
CMD_RESET, 0, timeout_us, XHCI_STATE_REMOVING);
if (ret)
return ret;

2
drivers/usb/host/xhci.h
View File

@ -2084,6 +2084,8 @@ void xhci_free_container_ctx(struct xhci_hcd *xhci,
/* xHCI host controller glue */
typedef void (*xhci_get_quirks_t)(struct device *, struct xhci_hcd *);
int xhci_handshake(void __iomem *ptr, u32 mask, u32 done, u64 timeout_us);
int xhci_handshake_check_state(struct xhci_hcd *xhci, void __iomem *ptr,
u32 mask, u32 done, int usec, unsigned int exit_state);
void xhci_quiesce(struct xhci_hcd *xhci);
int xhci_halt(struct xhci_hcd *xhci);
int xhci_start(struct xhci_hcd *xhci);