linux-kernel - [RFC PATCH 2/2] PM / devfreq: rk3399

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: <20220405184816.RFC.2.I2d73b403944f0b8b5871a77585b73f31ccc62999@changeid>
Date:   Tue,  5 Apr 2022 18:48:42 -0700
From:   Brian Norris <briannorris@...omium.org>
To:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Heiko Stuebner <heiko@...ech.de>
Cc:     linux-kernel@...r.kernel.org,
        Elaine Zhang <zhangqing@...k-chips.com>,
        linux-pm@...r.kernel.org, Doug Anderson <dianders@...omium.org>,
        linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org,
        Brian Norris <briannorris@...omium.org>
Subject: [RFC PATCH 2/2] PM / devfreq: rk3399_dmc: Block PMU during transitions

See the previous patch ("soc: rockchip: power-domain: Manage resource
conflicts with firmware") for a thorough explanation of the conflicts.
While ARM Trusted Firmware may be modifying memory controller and
power-domain states, we need to block the kernel's power-domain driver.

If the power-domain driver is disabled, there is no resource conflict
and this becomes a no-op.

Signed-off-by: Brian Norris <briannorris@...omium.org>
---

 drivers/devfreq/rk3399_dmc.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c
index e494d1497d60..daff40702615 100644
--- a/drivers/devfreq/rk3399_dmc.c
+++ b/drivers/devfreq/rk3399_dmc.c
@@ -21,6 +21,7 @@
 #include <linux/rwsem.h>
 #include <linux/suspend.h>
 
+#include <soc/rockchip/pm_domains.h>
 #include <soc/rockchip/rk3399_grf.h>
 #include <soc/rockchip/rockchip_sip.h>
 
@@ -93,6 +94,16 @@ static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq,
 
 	mutex_lock(&dmcfreq->lock);
 
+	/*
+	 * Ensure power-domain transitions don't interfere with ARM Trusted
+	 * Firmware power-domain idling.
+	 */
+	err = rockchip_pmu_block();
+	if (err) {
+		dev_err(dev, "Failed to block PMU: %d\n", err);
+		goto out_unlock;
+	}
+
 	/*
 	 * Some idle parameters may be based on the DDR controller clock, which
 	 * is half of the DDR frequency.
@@ -198,6 +209,8 @@ static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq,
 	dmcfreq->volt = target_volt;
 
 out:
+	rockchip_pmu_unblock();
+out_unlock:
 	mutex_unlock(&dmcfreq->lock);
 	return err;
 }
-- 
2.35.1.1094.g7c7d902a7c-goog