From: Geert Uytterhoeven <geert+renesas@glider.be>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Gilad Ben-Yossef <gilad@benyossef.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
"David S . Miller" <davem@davemloft.net>,
"Rafael J . Wysocki" <rafael@kernel.org>
Cc: Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
Felipe Balbi <balbi@kernel.org>,
Alan Stern <stern@rowland.harvard.edu>,
Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Mathias Nyman <mathias.nyman@intel.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Chunfeng Yun <chunfeng.yun@mediatek.com>, Bin Liu <b-liu@ti.com>,
linux-crypto@vger.kernel.org, linux-pm@vger.kernel.org,
linux-renesas-soc@vger.kernel.org, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org,
Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH 1/2] debugfs: regset32: Add Runtime PM support
Date: Fri, 24 Jan 2020 14:29:56 +0100 [thread overview]
Message-ID: <20200124132957.15769-2-geert+renesas@glider.be> (raw)
In-Reply-To: <20200124132957.15769-1-geert+renesas@glider.be>
Hardware registers of devices under control of power management cannot
be accessed at all times. If such a device is suspended, register
accesses may lead to undefined behavior, like reading bogus values, or
causing exceptions or system locks.
Extend struct debugfs_regset32 with an optional field to let device
drivers specify the device the registers in the set belong to. This
allows debugfs_show_regset32() to make sure the device is resumed while
its registers are being read.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
fs/debugfs/file.c | 8 ++++++++
include/linux/debugfs.h | 1 +
2 files changed, 9 insertions(+)
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index dede25247b81f72a..5e52d68421c678f2 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -18,6 +18,7 @@
#include <linux/slab.h>
#include <linux/atomic.h>
#include <linux/device.h>
+#include <linux/pm_runtime.h>
#include <linux/poll.h>
#include <linux/security.h>
@@ -1057,7 +1058,14 @@ static int debugfs_show_regset32(struct seq_file *s, void *data)
{
struct debugfs_regset32 *regset = s->private;
+ if (regset->dev)
+ pm_runtime_get_sync(regset->dev);
+
debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
+
+ if (regset->dev)
+ pm_runtime_put(regset->dev);
+
return 0;
}
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index bf9b6cafa4c26a68..5d0783ae09f365ac 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -35,6 +35,7 @@ struct debugfs_regset32 {
const struct debugfs_reg32 *regs;
int nregs;
void __iomem *base;
+ struct device *dev; /* Optional device for Runtime PM */
};
extern struct dentry *arch_debugfs_dir;
--
2.17.1
next prev parent reply other threads:[~2020-01-24 13:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-24 13:29 [PATCH 0/2] Fix debugfs register access while suspended Geert Uytterhoeven
2020-01-24 13:29 ` Geert Uytterhoeven [this message]
2020-01-31 10:13 ` [PATCH 1/2] debugfs: regset32: Add Runtime PM support Rafael J. Wysocki
2020-02-10 19:01 ` Greg Kroah-Hartman
2020-01-24 13:29 ` [PATCH 2/2] crypto: ccree - fix debugfs register access while suspended Geert Uytterhoeven
2020-01-26 13:32 ` Gilad Ben-Yossef
2020-01-31 10:11 ` Rafael J. Wysocki
2020-01-24 16:24 ` [PATCH 0/2] Fix " Niklas Söderlund
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