netdev - [PATCH net-next 2/5] net: ipa: don't use ipa_clock_get() in "ipa

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Date:   Thu, 19 Aug 2021 17:19:24 -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: don't use ipa_clock_get() in "ipa_smp2p.c"

If the "modem-init" Device Tree property is present for a platform,
the modem performs early IPA hardware initialization, and signals
this is complete with an "ipa-setup-ready" SMP2P interrupt.  This
triggers a call to ipa_setup(), which requires the hardware to be
powered.

Replace the call to ipa_clock_get() in this case with a call to
pm_runtime_get_sync().  And replace the corresponding calls to
ipa_clock_put() with calls to pm_runtime_put() instead.

There is a chance we get an error when taking this power reference.
This is an unlikely scenario, where system suspend is initiated just
before the modem signals it has finished initializing the IPA
hardware.  For now we'll just accept that this could occur, and
report it if it does.

Signed-off-by: Alex Elder <elder@...aro.org>
---
 drivers/net/ipa/ipa_smp2p.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ipa/ipa_smp2p.c b/drivers/net/ipa/ipa_smp2p.c
index 04b977cf91593..f6e2061cd391c 100644
--- a/drivers/net/ipa/ipa_smp2p.c
+++ b/drivers/net/ipa/ipa_smp2p.c
@@ -16,7 +16,6 @@
 #include "ipa_smp2p.h"
 #include "ipa.h"
 #include "ipa_uc.h"
-#include "ipa_clock.h"
 
 /**
  * DOC: IPA SMP2P communication with the modem
@@ -153,6 +152,7 @@ static void ipa_smp2p_panic_notifier_unregister(struct ipa_smp2p *smp2p)
 static irqreturn_t ipa_smp2p_modem_setup_ready_isr(int irq, void *dev_id)
 {
 	struct ipa_smp2p *smp2p = dev_id;
+	struct device *dev;
 	int ret;
 
 	mutex_lock(&smp2p->mutex);
@@ -161,17 +161,20 @@ static irqreturn_t ipa_smp2p_modem_setup_ready_isr(int irq, void *dev_id)
 		goto out_mutex_unlock;
 	smp2p->disabled = true;		/* If any others arrive, ignore them */
 
-	/* The clock needs to be active for setup */
-	ret = ipa_clock_get(smp2p->ipa);
-	if (WARN_ON(ret < 0))
-		goto out_clock_put;
+	/* Power needs to be active for setup */
+	dev = &smp2p->ipa->pdev->dev;
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		dev_err(dev, "error %d getting power for setup\n", ret);
+		goto out_power_put;
+	}
 
 	/* An error here won't cause driver shutdown, so warn if one occurs */
 	ret = ipa_setup(smp2p->ipa);
 	WARN(ret != 0, "error %d from ipa_setup()\n", ret);
 
-out_clock_put:
-	(void)ipa_clock_put(smp2p->ipa);
+out_power_put:
+	(void)pm_runtime_put(dev);
 out_mutex_unlock:
 	mutex_unlock(&smp2p->mutex);
 
@@ -211,7 +214,7 @@ static void ipa_smp2p_clock_release(struct ipa *ipa)
 	if (!ipa->smp2p->clock_on)
 		return;
 
-	(void)ipa_clock_put(ipa);
+	(void)pm_runtime_put(&ipa->pdev->dev);
 	ipa->smp2p->clock_on = false;
 }
 
-- 
2.27.0