netdev - [PATCH 4/5] bus: mhi: host: Update the Time sync logic to read 64 bit register value

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250818-tsc_time_sync-v1-4-2747710693ba@oss.qualcomm.com>
Date: Mon, 18 Aug 2025 12:25:49 +0530
From: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
To: Manivannan Sadhasivam <mani@...nel.org>,
        Richard Cochran <richardcochran@...il.com>
Cc: mhi@...ts.linux.dev, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        taniya.das@....qualcomm.com, imran.shaik@....qualcomm.com,
        quic_vbadigan@...cinc.com, quic_mrana@...cinc.com,
        Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
Subject: [PATCH 4/5] bus: mhi: host: Update the Time sync logic to read 64
 bit register value

Instead of reading low and high of the mhi registers twice use 64 bit
register value to avoid any time penality.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
---
 drivers/bus/mhi/host/main.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
index b7ceeb7261b708d46572d1f68dc277b6e1186b6e..f628198218ef9dc760bbfc3ec496603d1a45dfc1 100644
--- a/drivers/bus/mhi/host/main.c
+++ b/drivers/bus/mhi/host/main.c
@@ -1719,6 +1719,7 @@ static int mhi_get_remote_time(struct mhi_controller *mhi_cntrl, struct mhi_time
 			       struct mhi_timesync_info *time)
 {
 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+	u64 val = U64_MAX;
 	int ret, i;
 
 	if (!mhi_tsync && !mhi_tsync->time_reg) {
@@ -1756,15 +1757,25 @@ static int mhi_get_remote_time(struct mhi_controller *mhi_cntrl, struct mhi_time
 	 * transition to L0.
 	 */
 	for (i = 0; i < MHI_NUM_BACK_TO_BACK_READS; i++) {
-		ret = mhi_read_reg(mhi_cntrl, mhi_tsync->time_reg,
-				   TSC_TIMESYNC_TIME_LOW_OFFSET, &time->t_dev_lo);
+		if (mhi_cntrl->read_reg64) {
+			ret = mhi_read_reg64(mhi_cntrl, mhi_tsync->time_reg,
+					     TSC_TIMESYNC_TIME_LOW_OFFSET, &val);
+		} else {
+			ret = mhi_read_reg(mhi_cntrl, mhi_tsync->time_reg,
+					   TSC_TIMESYNC_TIME_LOW_OFFSET, &time->t_dev_lo);
 
-		ret = mhi_read_reg(mhi_cntrl, mhi_tsync->time_reg,
-				   TSC_TIMESYNC_TIME_HIGH_OFFSET, &time->t_dev_hi);
+			ret = mhi_read_reg(mhi_cntrl, mhi_tsync->time_reg,
+					   TSC_TIMESYNC_TIME_HIGH_OFFSET, &time->t_dev_hi);
+		}
 	}
 
 	time->t_host_post = ktime_get_real();
 
+	if (mhi_cntrl->read_reg64) {
+		time->t_dev_lo = (u32)val;
+		time->t_dev_hi = (u32)(val >> 32);
+	}
+
 	local_irq_enable();
 	preempt_enable();
 

-- 
2.34.1