[PATCH] wifi: ath12k: PCI ops for wakeup/release MHI

[Kalle Valo]

Ramya Gnanasekar <quic_rgnanase at quicinc.com> writes:

> Wakeup/release MHI is not needed before pci_read/write for QCN9274.
> Since wakeup & release MHI is enabled for all QCN9274 and
> WCN7850, below MHI assert is seen in QCN9274
>
> [  784.906613] BUG: sleeping function called from invalid context at drivers/bus/mhi/host/pm.c:989
> [  784.906633] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/3
> [  784.906637] preempt_count: 503, expected: 0
> [  784.906641] RCU nest depth: 0, expected: 0
> [  784.906644] 2 locks held by swapper/3/0:
> [  784.906646]  #0: ffff8ed348e429e0 (&ab->ce.ce_lock){+.-.}-{2:2}, at: ath12k_ce_recv_process_cb+0xb3/0x2f0 [ath12k]
> [  784.906664]  #1: ffff8ed348e491f0 (&srng->lock_key#3){+.-.}-{2:2}, at: ath12k_ce_recv_process_cb+0xfb/0x2f0 [ath12k]
> [  784.906678] Preemption disabled at:
> [  784.906680] [<0000000000000000>] 0x0
> [  784.906686] CPU: 3 PID: 0 Comm: swapper/3 Tainted: G        W  O       6.1.0-rc2+ #3
> [  784.906688] Hardware name: Intel(R) Client Systems NUC8i7HVK/NUC8i7HVB, BIOS HNKBLi70.86A.0056.2019.0506.1527 05/06/2019
> [  784.906690] Call Trace:
> [  784.906691]  <IRQ>
> [  784.906693]  dump_stack_lvl+0x56/0x7b
> [  784.906698]  __might_resched+0x21c/0x270
> [  784.906704]  __mhi_device_get_sync+0x7d/0x1c0 [mhi]
> [  784.906714]  mhi_device_get_sync+0xd/0x20 [mhi]
> [  784.906719]  ath12k_pci_write32+0x75/0x170 [ath12k]
> [  784.906729]  ath12k_hal_srng_access_end+0x55/0xc0 [ath12k]
> [  784.906737]  ath12k_ce_recv_process_cb+0x1f3/0x2f0 [ath12k]
> [  784.906776]  ? ath12k_pci_ce_tasklet+0x11/0x30 [ath12k]
> [  784.906788]  ath12k_pci_ce_tasklet+0x11/0x30 [ath12k]
> [  784.906813]  tasklet_action_common.isra.18+0xb7/0xe0
> [  784.906820]  __do_softirq+0xd0/0x4c9
> [  784.906826]  irq_exit_rcu+0x88/0xe0
> [  784.906828]  common_interrupt+0xa5/0xc0
> [  784.906831]  </IRQ>
> [  784.906832]  <TASK>
>
> Adding function callbacks for MHI wakeup and release operations.
> QCN9274 does not need wakeup/release, function callbacks are initialized
> to NULL. In case of WCN7850, shadow registers are used to access rings.
> Since, shadow register's offset is less than ACCESS_ALWAYS_OFF,
> mhi_device_get_sync() or mhi_device_put() to wakeup
> and release mhi will not be called during service ring accesses.
>
> Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0-03171-QCAHKSWPL_SILICONZ-1
> Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0-03427-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.15378.4
>
> Signed-off-by: Ramya Gnanasekar <quic_rgnanase at quicinc.com>
>
> diff --git a/drivers/net/wireless/ath/ath12k/pci.c b/drivers/net/wireless/ath/ath12k/pci.c

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