mmc: sdhci: Fix issues with power IRQ handling

The SDHC core power control IRQ gets triggered when -
* there is a state change in power control bit (bit 0)
  of SDHCI_POWER_CONTROL register.
* there is a state change in 1.8V enable bit (bit 3) of
  SDHCI_HOST_CONTROL2 register.
* Bit 1 of SDHCI_SOFTWARE_RESET is set.

This patch addresses the following 2 issues -

The reset state of 1.8V enable bit in SDHCI_HOST_CONTROL2 is 0
which indicates 3.3V IO voltage. So, when MMC core layer tries to
set it to 3.3V before card detection, the IRQ doesn't get
triggered as there is no state change in this bit. Hence, with
the current code, the VDD IO voltage is never getting set to
3.3V. This patch fixes this issue by setting the VDD IO voltage
to 3.3V whenever SDHC gets powered up.

We get different IRQ ACK status for each of these requests -
power on, power off, IO high, IO low. As of now, the driver is
not considering the IRQ ACK for IO high and IO low requests and
is returing prematurely from check_power_status() based on the
previous ACK for power on/off requests. This is resulting voltage
switch errors during voltage switch sequence for SD/eMMC cards.
This issue is fixed by passing the request type to
check_power_status host op so that driver can wait for its
corresponding ACK from power IRQ.

Change-Id: I07707ac5df731a0d3e4abead28076f0bbbf75c0a
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
[subhashj@codeaurora.org: fixed compilation error]
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
[xiaonian@codeaurora.org: fix trivial merge conflict]
Signed-off-by: Xiaonian Wang <xiaonian@codeaurora.org>
diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index e5d21b4..ee82df3 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -201,7 +201,9 @@
 	struct sdhci_msm_pltfm_data *pdata;
 	struct mmc_host  *mmc;
 	struct sdhci_pltfm_data sdhci_msm_pdata;
-	wait_queue_head_t pwr_irq_wait;
+	u32 curr_pwr_state;
+	u32 curr_io_level;
+	struct completion pwr_irq_completion;
 	struct sdhci_msm_bus_vote msm_bus_vote;
 	u32 clk_rate; /* Keeps track of current clock rate that is set */
 };
@@ -1424,6 +1426,8 @@
 	u8 irq_status = 0;
 	u8 irq_ack = 0;
 	int ret = 0;
+	int pwr_state = 0, io_level = 0;
+	unsigned long flags;
 
 	irq_status = readb_relaxed(msm_host->core_mem + CORE_PWRCTL_STATUS);
 	pr_debug("%s: Received IRQ(%d), status=0x%x\n",
@@ -1442,21 +1446,33 @@
 	/* Handle BUS ON/OFF*/
 	if (irq_status & CORE_PWRCTL_BUS_ON) {
 		ret = sdhci_msm_setup_vreg(msm_host->pdata, true, false);
-		if (!ret)
+		if (!ret) {
 			ret = sdhci_msm_setup_pins(msm_host->pdata, true);
+			ret |= sdhci_msm_set_vdd_io_vol(msm_host->pdata,
+					VDD_IO_HIGH, 0);
+		}
 		if (ret)
 			irq_ack |= CORE_PWRCTL_BUS_FAIL;
 		else
 			irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
+
+		pwr_state = REQ_BUS_ON;
+		io_level = REQ_IO_HIGH;
 	}
 	if (irq_status & CORE_PWRCTL_BUS_OFF) {
 		ret = sdhci_msm_setup_vreg(msm_host->pdata, false, false);
-		if (!ret)
+		if (!ret) {
 			ret = sdhci_msm_setup_pins(msm_host->pdata, false);
+			ret |= sdhci_msm_set_vdd_io_vol(msm_host->pdata,
+					VDD_IO_LOW, 0);
+		}
 		if (ret)
 			irq_ack |= CORE_PWRCTL_BUS_FAIL;
 		else
 			irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
+
+		pwr_state = REQ_BUS_OFF;
+		io_level = REQ_IO_LOW;
 	}
 	/* Handle IO LOW/HIGH */
 	if (irq_status & CORE_PWRCTL_IO_LOW) {
@@ -1466,6 +1482,8 @@
 			irq_ack |= CORE_PWRCTL_IO_FAIL;
 		else
 			irq_ack |= CORE_PWRCTL_IO_SUCCESS;
+
+		io_level = REQ_IO_LOW;
 	}
 	if (irq_status & CORE_PWRCTL_IO_HIGH) {
 		/* Switch voltage High */
@@ -1474,6 +1492,8 @@
 			irq_ack |= CORE_PWRCTL_IO_FAIL;
 		else
 			irq_ack |= CORE_PWRCTL_IO_SUCCESS;
+
+		io_level = REQ_IO_HIGH;
 	}
 
 	/* ACK status to the core */
@@ -1486,11 +1506,11 @@
 	 */
 	mb();
 
-	if (irq_status & CORE_PWRCTL_IO_HIGH)
+	if (io_level & REQ_IO_HIGH)
 		writel_relaxed((readl_relaxed(host->ioaddr + CORE_VENDOR_SPEC) &
 				~CORE_IO_PAD_PWR_SWITCH),
 				host->ioaddr + CORE_VENDOR_SPEC);
-	if (irq_status & CORE_PWRCTL_IO_LOW)
+	else if (io_level & REQ_IO_LOW)
 		writel_relaxed((readl_relaxed(host->ioaddr + CORE_VENDOR_SPEC) |
 				CORE_IO_PAD_PWR_SWITCH),
 				host->ioaddr + CORE_VENDOR_SPEC);
@@ -1498,7 +1518,14 @@
 
 	pr_debug("%s: Handled IRQ(%d), ret=%d, ack=0x%x\n",
 		mmc_hostname(msm_host->mmc), irq, ret, irq_ack);
-	wake_up_interruptible(&msm_host->pwr_irq_wait);
+	spin_lock_irqsave(&host->lock, flags);
+	if (pwr_state)
+		msm_host->curr_pwr_state = pwr_state;
+	if (io_level)
+		msm_host->curr_io_level = io_level;
+	complete(&msm_host->pwr_irq_completion);
+	spin_unlock_irqrestore(&host->lock, flags);
+
 	return IRQ_HANDLED;
 }
 
@@ -1532,25 +1559,36 @@
 	return count;
 }
 
-static void sdhci_msm_check_power_status(struct sdhci_host *host)
+static void sdhci_msm_check_power_status(struct sdhci_host *host, u32 req_type)
 {
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct sdhci_msm_host *msm_host = pltfm_host->priv;
-	int ret = 0;
+	unsigned long flags;
+	bool done = false;
 
-	pr_debug("%s: %s: power status before waiting 0x%x\n",
-		mmc_hostname(host->mmc), __func__,
-		readb_relaxed(msm_host->core_mem + CORE_PWRCTL_CTL));
+	spin_lock_irqsave(&host->lock, flags);
+	pr_debug("%s: %s: request %d curr_pwr_state %x curr_io_level %x\n",
+			mmc_hostname(host->mmc), __func__, req_type,
+			msm_host->curr_pwr_state, msm_host->curr_io_level);
+	if ((req_type & msm_host->curr_pwr_state) ||
+			(req_type & msm_host->curr_io_level))
+		done = true;
+	spin_unlock_irqrestore(&host->lock, flags);
 
-	ret = wait_event_interruptible(msm_host->pwr_irq_wait,
-				       (readb_relaxed(msm_host->core_mem +
-						      CORE_PWRCTL_CTL)) != 0x0);
-	if (ret)
-		pr_warning("%s: %s: returned due to error %d\n",
-				mmc_hostname(host->mmc), __func__, ret);
-	pr_debug("%s: %s: ret %d power status after handling power IRQ 0x%x\n",
-		mmc_hostname(host->mmc), __func__, ret,
-		readb_relaxed(msm_host->core_mem + CORE_PWRCTL_CTL));
+	/*
+	 * This is needed here to hanlde a case where IRQ gets
+	 * triggered even before this function is called so that
+	 * x->done counter of completion gets reset. Otherwise,
+	 * next call to wait_for_completion returns immediately
+	 * without actually waiting for the IRQ to be handled.
+	 */
+	if (done)
+		init_completion(&msm_host->pwr_irq_completion);
+	else
+		wait_for_completion(&msm_host->pwr_irq_completion);
+
+	pr_debug("%s: %s: request %d done\n", mmc_hostname(host->mmc),
+			__func__, req_type);
 }
 
 static void sdhci_msm_toggle_cdr(struct sdhci_host *host, bool enable)
@@ -1779,7 +1817,6 @@
 		ret = -ENOMEM;
 		goto out;
 	}
-	init_waitqueue_head(&msm_host->pwr_irq_wait);
 
 	msm_host->sdhci_msm_pdata.ops = &sdhci_msm_ops;
 	host = sdhci_pltfm_init(pdev, &msm_host->sdhci_msm_pdata, 0);
@@ -1958,6 +1995,8 @@
 		INIT_DELAYED_WORK(&msm_host->msm_bus_vote.vote_work,
 				  sdhci_msm_bus_work);
 
+	init_completion(&msm_host->pwr_irq_completion);
+
 	if (gpio_is_valid(msm_host->pdata->status_gpio)) {
 		ret = mmc_gpio_request_cd(msm_host->mmc,
 				msm_host->pdata->status_gpio, 0);