[RFC] mmc: cqhci: clear pending interrupt and halt

[Peng Fan <peng.fan@nxp.com>]

On i.MX8MM, we are running Dual Linux OS, with 1st Linux using SD Card
as rootfs storage, 2nd Linux using eMMC as rootfs storage. We let the
the 1st linux configure power/clock for the 2nd Linux.

When the 2nd Linux is booting into rootfs stage, we let the 1st Linux
to destroy the 2nd linux, then restart the 1st linux, we met SDHCI dump
as following, after we clear the pending interrupt and halt CQCTL, issue
gone.

[ 1.334594] mmc2: Got command interrupt 0x00000001 even though no command operation was in progress.
[ 1.334595] mmc2: sdhci: ============ SDHCI REGISTER DUMP ===========
[ 1.334599] mmc2: sdhci: Sys addr: 0xa05dcc00 | Version: 0x00000002
[ 1.340819] lib80211: common routines for IEEE802.11 drivers
[ 1.345538] mmc2: sdhci: Blk size: 0x00000200 | Blk cnt: 0x00000000
[ 1.345541] mmc2: sdhci: Argument: 0x00018000 | Trn mode: 0x00000033
[ 1.345543] mmc2: sdhci: Present: 0x01f88008 | Host ctl: 0x00000031
[ 1.345547] mmc2: sdhci: Power: 0x00000002 | Blk gap: 0x00000080
[ 1.357903] mmc2: sdhci: Wake-up: 0x00000008 | Clock: 0x0000003f
[ 1.357905] mmc2: sdhci: Timeout: 0x0000008f | Int stat: 0x00000000
[ 1.357908] mmc2: sdhci: Int enab: 0x107f100b | Sig enab: 0x107f100b
[ 1.357911] mmc2: sdhci: AC12 err: 0x00000000 | Slot int: 0x00000502
[ 1.370268] mmc2: sdhci: Caps: 0x07eb0000 | Caps_1: 0x0000b400
[ 1.370270] mmc2: sdhci: Cmd: 0x00000d1a | Max curr: 0x00ffffff
[ 1.370273] mmc2: sdhci: Resp[0]: 0x00000b00 | Resp[1]: 0xffffffff
[ 1.370276] mmc2: sdhci: Resp[2]: 0x328f5903 | Resp[3]: 0x00d00f00
[ 1.382132] mmc2: sdhci: Host ctl2: 0x00000000
[ 1.382135] mmc2: sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0xa2040208

[ 2.060932] mmc2: Unexpected interrupt 0x00004000.
[ 2.065538] mmc2: sdhci: ============ SDHCI REGISTER DUMP ===========
[ 2.071720] mmc2: sdhci: Sys addr: 0x00000000 | Version: 0x00000002
[ 2.077902] mmc2: sdhci: Blk size: 0x00000200 | Blk cnt: 0x00000001
[ 2.084083] mmc2: sdhci: Argument: 0x00000000 | Trn mode: 0x00000000
[ 2.090264] mmc2: sdhci: Present: 0x01f88009 | Host ctl: 0x00000011
[ 2.096446] mmc2: sdhci: Power: 0x00000002 | Blk gap: 0x00000080
[ 2.102627] mmc2: sdhci: Wake-up: 0x00000008 | Clock: 0x000010ff
[ 2.108809] mmc2: sdhci: Timeout: 0x0000008f | Int stat: 0x00004000
[ 2.114990] mmc2: sdhci: Int enab: 0x007f1003 | Sig enab: 0x007f1003
[ 2.121171] mmc2: sdhci: AC12 err: 0x00000000 | Slot int: 0x00000502
[ 2.127353] mmc2: sdhci: Caps: 0x07eb0000 | Caps_1: 0x0000b400
[ 2.133534] mmc2: sdhci: Cmd: 0x0000371a | Max curr: 0x00ffffff
[ 2.139715] mmc2: sdhci: Resp[0]: 0x00000900 | Resp[1]: 0xffffffff
[ 2.145896] mmc2: sdhci: Resp[2]: 0x328f5903 | Resp[3]: 0x00d00f00
[ 2.152077] mmc2: sdhci: Host ctl2: 0x00000000
[ 2.156342] mmc2: sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x00000000

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/mmc/host/cqhci.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/mmc/host/cqhci.c b/drivers/mmc/host/cqhci.c
index d59cb0a51964..4f41960ac7ad 100644
--- a/drivers/mmc/host/cqhci.c
+++ b/drivers/mmc/host/cqhci.c
@@ -1116,6 +1116,7 @@ int cqhci_init(struct cqhci_host *cq_host, struct mmc_host *mmc,
 	      bool dma64)
 {
 	int err;
+	u32 status;
 
 	cq_host->dma64 = dma64;
 	cq_host->mmc = mmc;
@@ -1139,6 +1140,10 @@ int cqhci_init(struct cqhci_host *cq_host, struct mmc_host *mmc,
 
 	spin_lock_init(&cq_host->lock);
 
+	status = cqhci_readl(cq_host, CQHCI_IS);
+	cqhci_writel(cq_host, status, CQHCI_IS);
+	cqhci_writel(cq_host, CQHCI_HALT, CQHCI_CTL);
+
 	init_completion(&cq_host->halt_comp);
 	init_waitqueue_head(&cq_host->wait_queue);
 
-- 
2.16.4