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Bluetooth: btintel_pcie: Refactor FLR to use device_reprobe()

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The FLR branch in btintel_pcie_reset_work() open-coded the entire
re-init sequence: btintel_pcie_release_hdev() (hci_unregister_dev +
hci_free_dev), pci_try_reset_function(), enable_interrupts /
config_msix / enable_bt / reset_ia / start_rx, then
btintel_pcie_setup_hdev() (hci_alloc_dev_priv + hci_register_dev).
Every probe() init step had to be kept in sync with this second
copy in the reset path, and any failure mid-sequence left state to
unwind by hand.

The PLDR path already delegates teardown and re-init to the PCI
core via device_reprobe(): .remove() destroys data through devres
and unregisters hdev, then .probe() rebuilds everything from
scratch. Apply the same model to FLR.

Introduce btintel_pcie_perform_flr() mirroring perform_pldr(). It
runs pci_try_reset_function() (required to avoid the device_lock
ABBA against btintel_pcie_remove(), which calls
disable_work_sync(&reset_work) while holding device_lock) followed
by device_reprobe(). On success, data is destroyed and a fresh
probe re-INIT_WORKs coredump_work with disable count 0, so
enable_work() must not be called; on failure, data is still alive
and the caller balances the earlier disable_work_sync(). The
contract is documented on the helper and reiterated at the
reset_work() call site.

reset_work() shrinks to interrupt/worker drain, dispatch on
reset_type, and the single asymmetry between the two paths. The
out_enable label, the manual unregister/register pair, and the
forward declaration of btintel_pcie_setup_hdev() are dropped.

No intended functional change; FLR and PLDR now share one
teardown contract.

Fixes: 256ab9520d ("Bluetooth: btintel_pcie: Support Function level reset")
Assisted-by: GitHub-Copilot:claude-4.7-opus
Signed-off-by: Kiran K <kiran.k@intel.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This commit is contained in:
Kiran K 2026-06-30 22:29:19 +05:30 committed by Luiz Augusto von Dentz
parent 6fef032af0
commit 9c36951474
1 changed files with 52 additions and 50 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

102
drivers/bluetooth/btintel_pcie.c
View File

@ -2127,6 +2127,9 @@ static int btintel_pcie_send_frame(struct hci_dev *hdev,
if (test_bit(BTINTEL_PCIE_CORE_HALTED, &data->flags))
return -ENODEV;
if (test_bit(BTINTEL_PCIE_RECOVERY_IN_PROGRESS, &data->flags))
return -ENODEV;
/* Due to the fw limitation, the type header of the packet should be
* 4 bytes unlike 1 byte for UART. In UART, the firmware can read
* the first byte to get the packet type and redirect the rest of data
@ -2485,7 +2488,6 @@ static void btintel_pcie_inc_recovery_count(struct pci_dev *pdev,
}
}
static int btintel_pcie_setup_hdev(struct btintel_pcie_data *data);
static void btintel_pcie_reset(struct hci_dev *hdev);
static int btintel_pcie_acpi_reset_method(struct btintel_pcie_data *data)
@ -2596,12 +2598,45 @@ static void btintel_pcie_perform_pldr(struct btintel_pcie_data *data)
}
}
/*
* Issue a Function Level Reset and hand teardown/re-init off to the PCI
* core via device_reprobe(), mirroring the PLDR path's contract.
*
* Caller must hold pci_lock_rescan_remove() and must have already
* disabled interrupts and drained both rx_work and coredump_work.
*/
static int btintel_pcie_perform_flr(struct btintel_pcie_data *data)
{
struct pci_dev *pdev = data->pdev;
int err;
/* pci_try_reset_function() avoids the device_lock ABBA against
* btintel_pcie_remove(): .remove() runs with device_lock held and
* then waits for this work via disable_work_sync(); the blocking
* pci_reset_function() would deadlock by trying to re-acquire
* device_lock here.
*/
err = pci_try_reset_function(pdev);
if (err) {
BT_ERR("Failed resetting the pcie device (%d)", err);
return err;
}
/* device_reprobe() always detaches the driver first (running
* .remove(), which frees 'data'); any re-probe failure leaves the
* device unbound but 'data' is already gone, so just log it.
*/
if (device_reprobe(&pdev->dev))
BT_ERR("BT reprobe failed for BDF:%s", pci_name(pdev));
return 0;
}
static void btintel_pcie_reset_work(struct work_struct *wk)
{
struct btintel_pcie_data *data =
container_of(wk, struct btintel_pcie_data, reset_work);
struct pci_dev *pdev = data->pdev;
int err;
pci_lock_rescan_remove();
@ -2621,60 +2656,27 @@ static void btintel_pcie_reset_work(struct work_struct *wk)
disable_work_sync(&data->coredump_work);
bt_dev_dbg(data->hdev, "Release bluetooth interface");
/* Both reset paths follow the same contract: on success they
* destroy 'data' via device_reprobe() (a fresh probe re-INIT_WORKs
* the coredump_work with disable count 0), so enable_work() must
* NOT be called on the success path. Only the FLR path can fail
* with 'data' still alive, in which case we balance the
* disable_work_sync() above so a later successful reset is not
* permanently blocked.
*
* pci_lock_rescan_remove() (held above) serializes against PCI
* device addition/removal (hotplug), so no device can be added to
* or removed from the bus list while this code runs.
*/
if (data->reset_type == BTINTEL_PCIE_IOSF_PRR_PLDR) {
/* This function holds pci_lock_rescan_remove(), which acquires
* pci_rescan_remove_lock. This mutex serializes against PCI device
* addition/removal (hotplug), so no device can be added to or
* removed from the bus list while this code runs.
*
* device_reprobe() inside btintel_pcie_perform_pldr() destroys
* 'data' via .remove(); a fresh probe re-INIT_WORKs the
* coredump_work with disable count 0, so we must not call
* enable_work() on this path.
*/
btintel_pcie_perform_pldr(data);
goto out;
}
btintel_pcie_release_hdev(data);
/* Use pci_try_reset_function() rather than pci_reset_function() to
* avoid an ABBA deadlock against btintel_pcie_remove(): the PCI core
* calls .remove() with device_lock held, and remove() then waits for
* this work via cancel_work_sync(); pci_reset_function() would in
* turn try to acquire the same device_lock, deadlocking both paths.
*/
err = pci_try_reset_function(pdev);
if (err) {
BT_ERR("Failed resetting the pcie device (%d)", err);
goto out_enable;
}
if (btintel_pcie_perform_flr(data))
enable_work(&data->coredump_work);
btintel_pcie_enable_interrupts(data);
btintel_pcie_config_msix(data);
err = btintel_pcie_enable_bt(data);
if (err) {
BT_ERR("Failed to enable bluetooth hardware after reset (%d)",
err);
goto out_enable;
}
btintel_pcie_reset_ia(data);
btintel_pcie_start_rx(data);
data->flags = 0;
err = btintel_pcie_setup_hdev(data);
if (err) {
BT_ERR("Failed registering hdev (%d)", err);
goto out_enable;
}
out_enable:
/* Balance disable_work_sync() above on every exit. Leaving the
* counter incremented on a failed reset would permanently disable
* coredump_work even after a later successful reset.
*/
enable_work(&data->coredump_work);
out:
pci_dev_put(pdev);
pci_unlock_rescan_remove();