From: Sahitya Tummala <stumm...@codeaurora.org>

Add support API which will check if power irq is expected to be
generated and wait for the power irq to come and complete if the irq is
expected.

Signed-off-by: Sahitya Tummala <stumm...@codeaurora.org>
Signed-off-by: Vijay Viswanath <vvisw...@codeaurora.org>
---
 drivers/mmc/host/sdhci-msm.c | 125 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 123 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index f3e0489..6d3b1fd 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -123,6 +123,10 @@
 #define CMUX_SHIFT_PHASE_MASK  (7 << CMUX_SHIFT_PHASE_SHIFT)
 
 #define MSM_MMC_AUTOSUSPEND_DELAY_MS   50
+
+/* Timeout value to avoid infinite waiting for pwr_irq */
+#define MSM_PWR_IRQ_TIMEOUT_MS 5000
+
 struct sdhci_msm_host {
        struct platform_device *pdev;
        void __iomem *core_mem; /* MSM SDCC mapped address */
@@ -138,6 +142,11 @@ struct sdhci_msm_host {
        bool calibration_done;
        u8 saved_tuning_phase;
        bool use_cdclp533;
+       u32 curr_pwr_state;
+       u32 curr_io_level;
+#ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS
+       struct completion pwr_irq_completion;
+#endif
 };
 
 static unsigned int msm_get_clock_rate_for_bus_mode(struct sdhci_host *host,
@@ -995,6 +1004,90 @@ static void sdhci_msm_set_uhs_signaling(struct sdhci_host 
*host,
                sdhci_msm_hs400(host, &mmc->ios);
 }
 
+#ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS
+static inline void sdhci_msm_init_pwr_irq_completion(
+               struct sdhci_msm_host *msm_host)
+{
+       init_completion(&msm_host->pwr_irq_completion);
+}
+
+static inline void sdhci_msm_complete_pwr_irq_completion(
+               struct sdhci_msm_host *msm_host)
+{
+       complete(&msm_host->pwr_irq_completion);
+}
+
+/*
+ * sdhci_msm_check_power_status API should be called when registers writes
+ * which can toggle sdhci IO bus ON/OFF or change IO lines HIGH/LOW happens.
+ * To what state the register writes will change the IO lines should be passed
+ * as the argument req_type. This API will check whether the IO line's state
+ * is already the expected state and will wait for power irq only if
+ * power irq is expected to be trigerred based on the current IO line state
+ * and expected IO line state.
+ */
+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 = sdhci_pltfm_priv(pltfm_host);
+       unsigned long flags;
+       bool done = false;
+
+       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);
+
+       /*
+        * The IRQ for request type IO High/LOW will be generated when -
+        * there is a state change in 1.8V enable bit (bit 3) of
+        * SDHCI_HOST_CONTROL2 register. The reset state of that bit is 0
+        * which indicates 3.3V IO voltage. So, when MMC core layer tries
+        * to set it to 3.3V before card detection happens, the
+        * IRQ doesn't get triggered as there is no state change in this bit.
+        * The driver already handles this case by changing the IO voltage
+        * level to high as part of controller power up sequence. Hence, check
+        * for host->pwr to handle a case where IO voltage high request is
+        * issued even before controller power up.
+        */
+       if ((req_type & REQ_IO_HIGH) && !host->pwr) {
+               pr_debug("%s: do not wait for power IRQ that never comes\n",
+                               mmc_hostname(host->mmc));
+               spin_unlock_irqrestore(&host->lock, flags);
+               return;
+       }
+       if ((req_type & msm_host->curr_pwr_state) ||
+                       (req_type & msm_host->curr_io_level))
+               done = true;
+       spin_unlock_irqrestore(&host->lock, flags);
+       /*
+        * 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 if (!wait_for_completion_timeout(&msm_host->pwr_irq_completion,
+                               msecs_to_jiffies(MSM_PWR_IRQ_TIMEOUT_MS)))
+               __WARN_printf("%s: request(%d) timed out waiting for pwr_irq\n",
+                               mmc_hostname(host->mmc), req_type);
+       pr_debug("%s: %s: request %d done\n", mmc_hostname(host->mmc),
+                       __func__, req_type);
+}
+#else
+static inline void sdhci_msm_init_pwr_irq_completion(
+               struct sdhci_msm_host *msm_host)
+{
+}
+
+static inline void sdhci_msm_complete_pwr_irq_completion(
+               struct sdhci_msm_host *msm_host)
+{
+}
+#endif
+
 static void sdhci_msm_dump_pwr_ctrl_regs(struct sdhci_host *host)
 {
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
@@ -1013,6 +1106,9 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host 
*host, int irq)
        struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
        u32 irq_status, irq_ack = 0;
        int retry = 10;
+       int pwr_state = 0, io_level = 0;
+       unsigned long flags;
+
 
        irq_status = readl_relaxed(msm_host->core_mem + CORE_PWRCTL_STATUS);
        irq_status &= INT_MASK;
@@ -1040,10 +1136,26 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host 
*host, int irq)
                udelay(10);
        }
 
-       if (irq_status & (CORE_PWRCTL_BUS_ON | CORE_PWRCTL_BUS_OFF))
+       /* Handle BUS ON/OFF*/
+       if (irq_status & CORE_PWRCTL_BUS_ON) {
+               pwr_state = REQ_BUS_ON;
+               io_level = REQ_IO_HIGH;
+               irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
+       }
+       if (irq_status & CORE_PWRCTL_BUS_OFF) {
+               pwr_state = REQ_BUS_OFF;
+               io_level = REQ_IO_LOW;
                irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
-       if (irq_status & (CORE_PWRCTL_IO_LOW | CORE_PWRCTL_IO_HIGH))
+       }
+       /* Handle IO LOW/HIGH */
+       if (irq_status & CORE_PWRCTL_IO_LOW) {
+               io_level = REQ_IO_LOW;
                irq_ack |= CORE_PWRCTL_IO_SUCCESS;
+       }
+       if (irq_status & CORE_PWRCTL_IO_HIGH) {
+               io_level = REQ_IO_HIGH;
+               irq_ack |= CORE_PWRCTL_IO_SUCCESS;
+       }
 
        /*
         * The driver has to acknowledge the interrupt, switch voltages and
@@ -1052,6 +1164,14 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host 
*host, int irq)
         */
        writel_relaxed(irq_ack, msm_host->core_mem + CORE_PWRCTL_CTL);
 
+       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;
+       spin_unlock_irqrestore(&host->lock, flags);
+       sdhci_msm_complete_pwr_irq_completion(msm_host);
+
        pr_debug("%s: %s: Handled IRQ(%d), irq_status=0x%x, ack=0x%x\n",
                mmc_hostname(msm_host->mmc), __func__, irq, irq_status,
                irq_ack);
@@ -1319,6 +1439,7 @@ static int sdhci_msm_probe(struct platform_device *pdev)
                goto clk_disable;
        }
 
+       sdhci_msm_init_pwr_irq_completion(msm_host);
        /* Enable pwr irq interrupts */
        writel_relaxed(INT_MASK, msm_host->core_mem + CORE_PWRCTL_MASK);
 
-- 
 Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux 
Foundation Collaborative Project.

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