linux-kernel - [PATCH 3/3] bus: mhi: keep device context through suspend cycles

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Message-Id: <20250630074330.253867-4-usama.anjum@collabora.com>
Date: Mon, 30 Jun 2025 12:43:30 +0500
From: Muhammad Usama Anjum <usama.anjum@...labora.com>
To: Manivannan Sadhasivam <mani@...nel.org>,
	Jeff Johnson <jjohnson@...nel.org>,
	Jeff Hugo <jeff.hugo@....qualcomm.com>,
	Youssef Samir <quic_yabdulra@...cinc.com>,
	Matthew Leung <quic_mattleun@...cinc.com>,
	Muhammad Usama Anjum <usama.anjum@...labora.com>,
	Yan Zhen <yanzhen@...o.com>,
	Alexander Wilhelm <alexander.wilhelm@...termo.com>,
	Alex Elder <elder@...nel.org>,
	Kunwu Chan <chentao@...inos.cn>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Siddartha Mohanadoss <smohanad@...eaurora.org>,
	Sujeev Dias <sdias@...eaurora.org>,
	Julia Lawall <julia.lawall@...6.fr>,
	John Crispin <john@...ozen.org>,
	Muna Sinada <quic_msinada@...cinc.com>,
	Venkateswara Naralasetty <quic_vnaralas@...cinc.com>,
	Maharaja Kennadyrajan <quic_mkenna@...cinc.com>,
	mhi@...ts.linux.dev,
	linux-arm-msm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-wireless@...r.kernel.org,
	ath11k@...ts.infradead.org
Cc: kernel@...labora.com
Subject: [PATCH 3/3] bus: mhi: keep device context through suspend cycles

Don't deinitialize the device context while going into suspend or
hibernation cycles. Otherwise the resume may fail if at resume time, the
memory pressure is high and no dma memory is available.

Tested-on: WCN6855 WLAN.HSP.1.1-03926.13-QCAHSPSWPL_V2_SILICONZ_CE-2.52297.6

Fixes: 3000f85b8f47 ("bus: mhi: core: Add support for basic PM operations")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@...labora.com>
---
 drivers/bus/mhi/host/init.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c
index 2e0f18c939e68..8f56e73fdc42e 100644
--- a/drivers/bus/mhi/host/init.c
+++ b/drivers/bus/mhi/host/init.c
@@ -1133,9 +1133,11 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
 
 	mutex_lock(&mhi_cntrl->pm_mutex);
 
-	ret = mhi_init_dev_ctxt(mhi_cntrl);
-	if (ret)
-		goto error_dev_ctxt;
+	if (!mhi_cntrl->mhi_ctxt) {
+		ret = mhi_init_dev_ctxt(mhi_cntrl);
+		if (ret)
+			goto error_dev_ctxt;
+	}
 
 	ret = mhi_read_reg(mhi_cntrl, mhi_cntrl->regs, BHIOFF, &bhi_off);
 	if (ret) {
@@ -1212,8 +1214,6 @@ void mhi_deinit_dev_ctxt(struct mhi_controller *mhi_cntrl)
 {
 	mhi_cntrl->bhi = NULL;
 	mhi_cntrl->bhie = NULL;
-
-	__mhi_deinit_dev_ctxt(mhi_cntrl);
 }
 
 void mhi_unprepare_after_power_down(struct mhi_controller *mhi_cntrl)
@@ -1234,6 +1234,7 @@ void mhi_unprepare_after_power_down(struct mhi_controller *mhi_cntrl)
 	}
 
 	mhi_deinit_dev_ctxt(mhi_cntrl);
+	__mhi_deinit_dev_ctxt(mhi_cntrl);
 }
 EXPORT_SYMBOL_GPL(mhi_unprepare_after_power_down);
 
-- 
2.39.5