net: ipa: get another clock for ipa_setup()

Two places call ipa_setup().  The first, ipa_probe(), holds an IPA
clock reference when calling ipa_setup() (if the AP is responsible
for IPA firmware loading).  But if the modem is loading IPA
firmware, ipa_smp2p_modem_setup_ready_isr() calls ipa_setup() after
the modem has signaled the hardware is ready.  This can happen at
any time, and there is no guarantee the hardware is active.

Have ipa_smp2p_modem_setup() take an IPA clock reference before it
calls ipa_setup(), and release it once setup is complete.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ipa/ipa_smp2p.c

@@ -156,11 +156,16 @@ static irqreturn_t ipa_smp2p_modem_setup_ready_isr(int irq, void *dev_id)
 	if (!smp2p->disabled) {
 		int ret;
 
+		/* The clock needs to be active for setup */
+		ipa_clock_get(smp2p->ipa);
+
 		ret = ipa_setup(smp2p->ipa);
 		if (ret)
 			dev_err(&smp2p->ipa->pdev->dev,
 				"error %d from ipa_setup()\n", ret);
 		smp2p->disabled = true;
+
+		ipa_clock_put(smp2p->ipa);
 	}
 
 	mutex_unlock(&smp2p->mutex);