mmc: cqhci: clear HALT state after CQE enable

While mmc0 enter suspend state, we need halt CQE to send legacy cmd(flush
cache) and disable cqe, for resume back, we enable CQE and not clear HALT
state.
In this case MediaTek mmc host controller will keep the value for HALT
state after CQE disable/enable flow, so the next CQE transfer after resume
will be timeout due to CQE is in HALT state, the log as below:
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: timeout for tag 2
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: ============ CQHCI REGISTER DUMP ===========
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Caps:      0x100020b6 | Version:  0x00000510
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Config:    0x00001103 | Control:  0x00000001
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Int stat:  0x00000000 | Int enab: 0x00000006
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Int sig:   0x00000006 | Int Coal: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: TDL base:  0xfd05f000 | TDL up32: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Doorbell:  0x8000203c | TCN:      0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Dev queue: 0x00000000 | Dev Pend: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Task clr:  0x00000000 | SSC1:     0x00001000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: SSC2:      0x00000001 | DCMD rsp: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: RED mask:  0xfdf9a080 | TERRI:    0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: Resp idx:  0x00000000 | Resp arg: 0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: CRNQP:     0x00000000 | CRNQDUN:  0x00000000
<4>.(4)[318:kworker/4:1H]mmc0: cqhci: CRNQIS:    0x00000000 | CRNQIE:   0x00000000

This change check HALT state after CQE enable, if CQE is in HALT state, we
will clear it.

Signed-off-by: Wenbin Mei <[email protected]>
Cc: [email protected]
Acked-by: Adrian Hunter <[email protected]>
Fixes: a408022 ("mmc: cqhci: support for command queue enabled host")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ulf Hansson <[email protected]>

Author: wenbinmei1

drivers/mmc/host/cqhci-core.c

@@ -282,6 +282,9 @@ static void __cqhci_enable(struct cqhci_host *cq_host)
 
 	cqhci_writel(cq_host, cqcfg, CQHCI_CFG);
 
+	if (cqhci_readl(cq_host, CQHCI_CTL) & CQHCI_HALT)
+		cqhci_writel(cq_host, 0, CQHCI_CTL);
+
 	mmc->cqe_on = true;
 
 	if (cq_host->ops->enable)