From 30332eeefec8f83afcea00c360f99ef64b87f220 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Tue, 11 Feb 2020 19:18:55 +0100 Subject: debugfs: regset32: Add Runtime PM support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 lock-ups. 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 Reviewed-by: Niklas Söderlund Reviewed-by: Greg Kroah-Hartman Acked-by: Rafael J. Wysocki Signed-off-by: Herbert Xu --- 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 634b09d18b77..204734f8d1c6 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include @@ -1060,7 +1061,14 @@ 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 3d013de64f70..ad416853e722 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; -- cgit v1.2.3