linux-kernel - [PATCH net-next 2/5] net: ipa: get another clock for ipa

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Date:   Tue, 27 Jul 2021 16:19:30 -0500
From:   Alex Elder <elder@...aro.org>
To:     davem@...emloft.net, kuba@...nel.org
Cc:     bjorn.andersson@...aro.org, evgreen@...omium.org,
        cpratapa@...eaurora.org, subashab@...eaurora.org, elder@...nel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH net-next 2/5] 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@...aro.org>
---
 drivers/net/ipa/ipa_smp2p.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ipa/ipa_smp2p.c b/drivers/net/ipa/ipa_smp2p.c
index 93270e50b6b35..0d15438a79e2d 100644
--- a/drivers/net/ipa/ipa_smp2p.c
+++ b/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);
-- 
2.27.0