linux-kernel - [PATCH v2] soc: tegra: pmc: Use syscore PM ops

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Date:	Tue, 23 Dec 2014 21:25:11 +0300
From:	Dmitry Osipenko <digetx@...il.com>
To:	digetx@...il.com, Stephen Warren <swarren@...dotorg.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Alexandre Courbot <gnurou@...il.com>
Cc:	<stable@...r.kernel.org>, linux-tegra@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2] soc: tegra: pmc: Use syscore PM ops

Commit 7232398abc6a ("ARM: tegra: Convert PMC to a driver") changed tegra_resume()
location storing from late to early, and as a result, broke suspend on Tegra20.
PMC scratch register 41 is used by tegra LP1 resume code for retrieving stored
physical memory address of common resume function and in the same time used by
tegra20_cpu_shutdown() (which is shared by Tegra20 cpuidle driver and platform
smp code) for storing cpu1 "resettable" status. It implies strict order of
scratch register usage, otherwise resume function address is lost on Tegra20
after disabling non-boot CPU's on suspend. Fix it by making PMC driver use
syscore PM ops to ensure correct order of scratch register usage.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
Fixes: 7232398abc6a (ARM: tegra: Convert PMC to a driver)
Cc: <stable@...r.kernel.org> # v3.17+
---

v2: changed commit description

 drivers/soc/tegra/pmc.c | 37 +++++++++++++++++++------------------
 1 file changed, 19 insertions(+), 18 deletions(-)

diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
index a2c0ceb..4ebd94a 100644
--- a/drivers/soc/tegra/pmc.c
+++ b/drivers/soc/tegra/pmc.c
@@ -33,6 +33,7 @@
 #include <linux/reset.h>
 #include <linux/seq_file.h>
 #include <linux/spinlock.h>
+#include <linux/syscore_ops.h>
 
 #include <soc/tegra/common.h>
 #include <soc/tegra/fuse.h>
@@ -703,6 +704,23 @@ static void tegra_pmc_init(struct tegra_pmc *pmc)
 	tegra_pmc_writel(value, PMC_CNTRL);
 }
 
+static int tegra_pmc_suspend(void)
+{
+	tegra_pmc_writel(virt_to_phys(tegra_resume), PMC_SCRATCH41);
+
+	return 0;
+}
+
+static void tegra_pmc_resume(void)
+{
+	tegra_pmc_writel(0x0, PMC_SCRATCH41);
+}
+
+static struct syscore_ops tegra_pmc_syscore_ops = {
+	.suspend = tegra_pmc_suspend,
+	.resume = tegra_pmc_resume,
+};
+
 static int tegra_pmc_probe(struct platform_device *pdev)
 {
 	void __iomem *base = pmc->base;
@@ -736,27 +754,11 @@ static int tegra_pmc_probe(struct platform_device *pdev)
 			return err;
 	}
 
-	return 0;
-}
-
-#ifdef CONFIG_PM_SLEEP
-static int tegra_pmc_suspend(struct device *dev)
-{
-	tegra_pmc_writel(virt_to_phys(tegra_resume), PMC_SCRATCH41);
+	register_syscore_ops(&tegra_pmc_syscore_ops);
 
 	return 0;
 }
 
-static int tegra_pmc_resume(struct device *dev)
-{
-	tegra_pmc_writel(0x0, PMC_SCRATCH41);
-
-	return 0;
-}
-#endif
-
-static SIMPLE_DEV_PM_OPS(tegra_pmc_pm_ops, tegra_pmc_suspend, tegra_pmc_resume);
-
 static const char * const tegra20_powergates[] = {
 	[TEGRA_POWERGATE_CPU] = "cpu",
 	[TEGRA_POWERGATE_3D] = "3d",
@@ -894,7 +896,6 @@ static struct platform_driver tegra_pmc_driver = {
 		.name = "tegra-pmc",
 		.suppress_bind_attrs = true,
 		.of_match_table = tegra_pmc_match,
-		.pm = &tegra_pmc_pm_ops,
 	},
 	.probe = tegra_pmc_probe,
 };
-- 
2.2.0

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