mfd: Update db8500-prmcu hostport_access enable

Force the Modem wakeup by asserting the CaWakeReq signal before the
hostaccess_req/ack ping-pong sequence. The Awake_req signal is de-asserted
asserted at the same time than the hostaccess_req. Return error on failure
case so that the client using this can take appropiate steps.

Signed-off-by: Arun Murthy <arun.murthy@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 19 insertions, 26 deletions

diff --git a/drivers/mfd/db8500-prcmu.c b/drivers/mfd/db8500-prcmu.c
index bf5a054a2b91..f4adcabb2a51 100644
--- a/drivers/mfd/db8500-prcmu.c
+++ b/drivers/mfd/db8500-prcmu.c
@@ -2269,10 +2269,10 @@ int prcmu_abb_write(u8 slave, u8 reg, u8 *value, u8 size)
 /**
  * prcmu_ac_wake_req - should be called whenever ARM wants to wakeup Modem
  */
-void prcmu_ac_wake_req(void)
+int prcmu_ac_wake_req(void)
 {
         u32 val;
-        u32 status;
+        int ret = 0;
 
         mutex_lock(&mb0_transfer.ac_wake_lock);
 
@@ -2282,39 +2282,32 @@ void prcmu_ac_wake_req(void)
 
         atomic_set(&ac_wake_req_state, 1);
 
-retry:
-        writel((val | PRCM_HOSTACCESS_REQ_HOSTACCESS_REQ), PRCM_HOSTACCESS_REQ);
+        /*
+         * Force Modem Wake-up before hostaccess_req ping-pong.
+         * It prevents Modem to enter in Sleep while acking the hostaccess
+         * request. The 31us delay has been calculated by HWI.
+         */
+        val |= PRCM_HOSTACCESS_REQ_WAKE_REQ;
+        writel(val, PRCM_HOSTACCESS_REQ);
+
+        udelay(31);
+
+        val |= PRCM_HOSTACCESS_REQ_HOSTACCESS_REQ;
+        writel(val, PRCM_HOSTACCESS_REQ);
 
         if (!wait_for_completion_timeout(&mb0_transfer.ac_wake_work,
                         msecs_to_jiffies(5000))) {
+#if defined(CONFIG_DBX500_PRCMU_DEBUG)
+                db8500_prcmu_debug_dump(__func__, true, true);
+#endif
                 pr_crit("prcmu: %s timed out (5 s) waiting for a reply.\n",
                         __func__);
-                goto unlock_and_return;
-        }
-
-        /*
-         * The modem can generate an AC_WAKE_ACK, and then still go to sleep.
-         * As a workaround, we wait, and then check that the modem is indeed
-         * awake (in terms of the value of the PRCM_MOD_AWAKE_STATUS
-         * register, which may not be the whole truth).
-         */
-        udelay(400);
-        status = (readl(PRCM_MOD_AWAKE_STATUS) & BITS(0, 2));
-        if (status != (PRCM_MOD_AWAKE_STATUS_PRCM_MOD_AAPD_AWAKE |
-                        PRCM_MOD_AWAKE_STATUS_PRCM_MOD_COREPD_AWAKE)) {
-                pr_err("prcmu: %s received ack, but modem not awake (0x%X).\n",
-                        __func__, status);
-                udelay(1200);
-                writel(val, PRCM_HOSTACCESS_REQ);
-                if (wait_for_completion_timeout(&mb0_transfer.ac_wake_work,
-                                msecs_to_jiffies(5000)))
-                        goto retry;
-                pr_crit("prcmu: %s timed out (5 s) waiting for AC_SLEEP_ACK.\n",
-                        __func__);
+                ret = -EFAULT;
         }
 
 unlock_and_return:
         mutex_unlock(&mb0_transfer.ac_wake_lock);
+        return ret;
 }
 
 /**