From: Geert Uytterhoeven <geert+renesas@glider.be>
To: Philipp Zabel <p.zabel@pengutronix.de>,
Eric Auger <eric.auger@redhat.com>,
Alex Williamson <alex.williamson@redhat.com>
Cc: kvm@vger.kernel.org, devicetree@vger.kernel.org,
linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org,
Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH/RFC v4 2/2] vfio: platform: Add generic reset controller support
Date: Mon, 17 Sep 2018 18:39:55 +0200 [thread overview]
Message-ID: <20180917163955.19023-3-geert+renesas@glider.be> (raw)
In-Reply-To: <20180917163955.19023-1-geert+renesas@glider.be>
Vfio-platform requires dedicated reset support, provided either by ACPI,
or, on DT platforms, by a device-specific reset driver matching against
the device's compatible value.
On many SoCs, devices are connected to an SoC-internal reset controller.
If the reset hierarchy is described in DT using "resets" properties, or
in lookup tables in platform code, such devices can be reset in a
generic way through the reset controller subsystem. Hence add support
for this, avoiding the need to write device-specific reset drivers for
each single device on affected SoCs.
Devices that do require a more complex reset procedure can still provide
a device-specific reset driver, as that takes precedence.
Note that this functionality depends on CONFIG_RESET_CONTROLLER=y, and
becomes a no-op (as in: "No reset function found for device") if reset
controller support is disabled.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
---
v4:
- Add Reviewed-by,
- Use new RFC reset_control_get_dedicated() instead of
of_reset_control_get_exclusive(), to (a) make it more generic, and
(b) make sure the reset returned is really a dedicated reset, and
does not affect other devices,
v3:
- Add Reviewed-by,
- Merge similar checks in vfio_platform_has_reset(),
v2:
- Don't store error values in vdev->reset_control,
- Use of_reset_control_get_exclusive() instead of
__of_reset_control_get(),
- Improve description.
---
drivers/vfio/platform/vfio_platform_common.c | 20 +++++++++++++++++--
drivers/vfio/platform/vfio_platform_private.h | 1 +
2 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index c0cd824be2b767be..eb77fe87f3663e3e 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -18,6 +18,7 @@
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/pm_runtime.h>
+#include <linux/reset.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/uaccess.h>
@@ -113,11 +114,13 @@ static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
if (VFIO_PLATFORM_IS_ACPI(vdev))
return vfio_platform_acpi_has_reset(vdev);
- return vdev->of_reset ? true : false;
+ return vdev->of_reset || vdev->reset_control;
}
static int vfio_platform_get_reset(struct vfio_platform_device *vdev)
{
+ struct reset_control *rstc;
+
if (VFIO_PLATFORM_IS_ACPI(vdev))
return vfio_platform_acpi_has_reset(vdev) ? 0 : -ENOENT;
@@ -128,8 +131,16 @@ static int vfio_platform_get_reset(struct vfio_platform_device *vdev)
vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
&vdev->reset_module);
}
+ if (vdev->of_reset)
+ return 0;
+
+ rstc = reset_control_get_dedicated(vdev->device, NULL);
+ if (!IS_ERR(rstc)) {
+ vdev->reset_control = rstc;
+ return 0;
+ }
- return vdev->of_reset ? 0 : -ENOENT;
+ return PTR_ERR(rstc);
}
static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
@@ -139,6 +150,8 @@ static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
if (vdev->of_reset)
module_put(vdev->reset_module);
+
+ reset_control_put(vdev->reset_control);
}
static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
@@ -218,6 +231,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
} else if (vdev->of_reset) {
dev_info(vdev->device, "reset\n");
return vdev->of_reset(vdev);
+ } else if (vdev->reset_control) {
+ dev_info(vdev->device, "reset\n");
+ return reset_control_reset(vdev->reset_control);
}
dev_warn(vdev->device, "no reset function found!\n");
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 85ffe5d9d1abd94e..a56e80ae5986540b 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -60,6 +60,7 @@ struct vfio_platform_device {
const char *compat;
const char *acpihid;
struct module *reset_module;
+ struct reset_control *reset_control;
struct device *device;
/*
--
2.17.1
next prev parent reply other threads:[~2018-09-17 16:40 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-17 16:39 [PATCH/RFC v4 0/2] vfio: platform: Add generic reset controller support Geert Uytterhoeven
2018-09-17 16:39 ` [PATCH/RFC v4 1/2] reset: Add support for dedicated reset controls Geert Uytterhoeven
2018-09-18 6:42 ` Geert Uytterhoeven
2018-09-19 12:09 ` Auger Eric
2018-09-19 13:16 ` Geert Uytterhoeven
2018-09-19 15:28 ` Auger Eric
2018-09-19 14:58 ` Philipp Zabel
2018-09-19 15:24 ` Geert Uytterhoeven
2018-09-20 9:27 ` Philipp Zabel
2018-09-20 9:37 ` Geert Uytterhoeven
2018-09-17 16:39 ` Geert Uytterhoeven [this message]
2018-09-19 12:36 ` [PATCH/RFC v4 2/2] vfio: platform: Add generic reset controller support Auger Eric
2018-09-19 12:54 ` Geert Uytterhoeven
2018-09-19 15:31 ` Auger Eric
2018-09-19 18:19 ` Alex Williamson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180917163955.19023-3-geert+renesas@glider.be \
--to=geert+renesas@glider.be \
--cc=alex.williamson@redhat.com \
--cc=devicetree@vger.kernel.org \
--cc=eric.auger@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-renesas-soc@vger.kernel.org \
--cc=p.zabel@pengutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).