| Message ID | 1519200222-20623-3-git-send-email-andr2000@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 21/02/18 09:03, Oleksandr Andrushchenko wrote: > From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> > > Initial handling for Xen bus states: implement > Xen bus state machine for the frontend driver according to > the state diagram and recovery flow from display para-virtualized > protocol: xen/interface/io/displif.h. > > Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> > --- > drivers/gpu/drm/xen/xen_drm_front.c | 124 +++++++++++++++++++++++++++++++++++- > drivers/gpu/drm/xen/xen_drm_front.h | 26 ++++++++ > 2 files changed, 149 insertions(+), 1 deletion(-) > create mode 100644 drivers/gpu/drm/xen/xen_drm_front.h > > diff --git a/drivers/gpu/drm/xen/xen_drm_front.c b/drivers/gpu/drm/xen/xen_drm_front.c > index fd372fb464a1..d0306f9d660d 100644 > --- a/drivers/gpu/drm/xen/xen_drm_front.c > +++ b/drivers/gpu/drm/xen/xen_drm_front.c > @@ -24,19 +24,141 @@ > > #include <xen/interface/io/displif.h> > > +#include "xen_drm_front.h" > + > +static void xen_drv_remove_internal(struct xen_drm_front_info *front_info) > +{ > +} > + > +static int backend_on_initwait(struct xen_drm_front_info *front_info) > +{ > + return 0; > +} > + > +static int backend_on_connected(struct xen_drm_front_info *front_info) > +{ > + return 0; > +} > + > +static void backend_on_disconnected(struct xen_drm_front_info *front_info) > +{ > + xenbus_switch_state(front_info->xb_dev, XenbusStateInitialising); > +} > + > static void backend_on_changed(struct xenbus_device *xb_dev, > enum xenbus_state backend_state) > { > + struct xen_drm_front_info *front_info = dev_get_drvdata(&xb_dev->dev); > + int ret; > + > + DRM_DEBUG("Backend state is %s, front is %s\n", > + xenbus_strstate(backend_state), > + xenbus_strstate(xb_dev->state)); > + > + switch (backend_state) { > + case XenbusStateReconfiguring: > + /* fall through */ > + case XenbusStateReconfigured: > + /* fall through */ > + case XenbusStateInitialised: > + break; > + > + case XenbusStateInitialising: > + /* recovering after backend unexpected closure */ > + backend_on_disconnected(front_info); > + break; > + > + case XenbusStateInitWait: > + /* recovering after backend unexpected closure */ > + backend_on_disconnected(front_info); > + if (xb_dev->state != XenbusStateInitialising) > + break; > + > + ret = backend_on_initwait(front_info); > + if (ret < 0) > + xenbus_dev_fatal(xb_dev, ret, "initializing frontend"); > + else > + xenbus_switch_state(xb_dev, XenbusStateInitialised); > + break; > + > + case XenbusStateConnected: > + if (xb_dev->state != XenbusStateInitialised) > + break; > + > + ret = backend_on_connected(front_info); > + if (ret < 0) > + xenbus_dev_fatal(xb_dev, ret, "initializing DRM driver"); > + else > + xenbus_switch_state(xb_dev, XenbusStateConnected); > + break; > + > + case XenbusStateClosing: > + /* > + * in this state backend starts freeing resources, > + * so let it go into closed state, so we can also > + * remove ours > + */ > + break; > + > + case XenbusStateUnknown: > + /* fall through */ > + case XenbusStateClosed: > + if (xb_dev->state == XenbusStateClosed) > + break; > + > + backend_on_disconnected(front_info); > + break; > + } > } > > static int xen_drv_probe(struct xenbus_device *xb_dev, > const struct xenbus_device_id *id) > { > - return 0; > + struct xen_drm_front_info *front_info; > + > + front_info = devm_kzalloc(&xb_dev->dev, > + sizeof(*front_info), GFP_KERNEL); > + if (!front_info) { > + xenbus_dev_fatal(xb_dev, -ENOMEM, "allocating device memory"); No need for message in case of allocation failure: this is handled in memory allocation already. Juergen
On 02/21/2018 10:23 AM, Juergen Gross wrote: > On 21/02/18 09:03, Oleksandr Andrushchenko wrote: >> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> >> >> Initial handling for Xen bus states: implement >> Xen bus state machine for the frontend driver according to >> the state diagram and recovery flow from display para-virtualized >> protocol: xen/interface/io/displif.h. >> >> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> >> --- >> drivers/gpu/drm/xen/xen_drm_front.c | 124 +++++++++++++++++++++++++++++++++++- >> drivers/gpu/drm/xen/xen_drm_front.h | 26 ++++++++ >> 2 files changed, 149 insertions(+), 1 deletion(-) >> create mode 100644 drivers/gpu/drm/xen/xen_drm_front.h >> >> diff --git a/drivers/gpu/drm/xen/xen_drm_front.c b/drivers/gpu/drm/xen/xen_drm_front.c >> index fd372fb464a1..d0306f9d660d 100644 >> --- a/drivers/gpu/drm/xen/xen_drm_front.c >> +++ b/drivers/gpu/drm/xen/xen_drm_front.c >> @@ -24,19 +24,141 @@ >> >> #include <xen/interface/io/displif.h> >> >> +#include "xen_drm_front.h" >> + >> +static void xen_drv_remove_internal(struct xen_drm_front_info *front_info) >> +{ >> +} >> + >> +static int backend_on_initwait(struct xen_drm_front_info *front_info) >> +{ >> + return 0; >> +} >> + >> +static int backend_on_connected(struct xen_drm_front_info *front_info) >> +{ >> + return 0; >> +} >> + >> +static void backend_on_disconnected(struct xen_drm_front_info *front_info) >> +{ >> + xenbus_switch_state(front_info->xb_dev, XenbusStateInitialising); >> +} >> + >> static void backend_on_changed(struct xenbus_device *xb_dev, >> enum xenbus_state backend_state) >> { >> + struct xen_drm_front_info *front_info = dev_get_drvdata(&xb_dev->dev); >> + int ret; >> + >> + DRM_DEBUG("Backend state is %s, front is %s\n", >> + xenbus_strstate(backend_state), >> + xenbus_strstate(xb_dev->state)); >> + >> + switch (backend_state) { >> + case XenbusStateReconfiguring: >> + /* fall through */ >> + case XenbusStateReconfigured: >> + /* fall through */ >> + case XenbusStateInitialised: >> + break; >> + >> + case XenbusStateInitialising: >> + /* recovering after backend unexpected closure */ >> + backend_on_disconnected(front_info); >> + break; >> + >> + case XenbusStateInitWait: >> + /* recovering after backend unexpected closure */ >> + backend_on_disconnected(front_info); >> + if (xb_dev->state != XenbusStateInitialising) >> + break; >> + >> + ret = backend_on_initwait(front_info); >> + if (ret < 0) >> + xenbus_dev_fatal(xb_dev, ret, "initializing frontend"); >> + else >> + xenbus_switch_state(xb_dev, XenbusStateInitialised); >> + break; >> + >> + case XenbusStateConnected: >> + if (xb_dev->state != XenbusStateInitialised) >> + break; >> + >> + ret = backend_on_connected(front_info); >> + if (ret < 0) >> + xenbus_dev_fatal(xb_dev, ret, "initializing DRM driver"); >> + else >> + xenbus_switch_state(xb_dev, XenbusStateConnected); >> + break; >> + >> + case XenbusStateClosing: >> + /* >> + * in this state backend starts freeing resources, >> + * so let it go into closed state, so we can also >> + * remove ours >> + */ >> + break; >> + >> + case XenbusStateUnknown: >> + /* fall through */ >> + case XenbusStateClosed: >> + if (xb_dev->state == XenbusStateClosed) >> + break; >> + >> + backend_on_disconnected(front_info); >> + break; >> + } >> } >> >> static int xen_drv_probe(struct xenbus_device *xb_dev, >> const struct xenbus_device_id *id) >> { >> - return 0; >> + struct xen_drm_front_info *front_info; >> + >> + front_info = devm_kzalloc(&xb_dev->dev, >> + sizeof(*front_info), GFP_KERNEL); >> + if (!front_info) { >> + xenbus_dev_fatal(xb_dev, -ENOMEM, "allocating device memory"); > No need for message in case of allocation failure: this is > handled in memory allocation already. Will remove, thank you > > Juergen
diff --git a/drivers/gpu/drm/xen/xen_drm_front.c b/drivers/gpu/drm/xen/xen_drm_front.c index fd372fb464a1..d0306f9d660d 100644 --- a/drivers/gpu/drm/xen/xen_drm_front.c +++ b/drivers/gpu/drm/xen/xen_drm_front.c @@ -24,19 +24,141 @@ #include <xen/interface/io/displif.h> +#include "xen_drm_front.h" + +static void xen_drv_remove_internal(struct xen_drm_front_info *front_info) +{ +} + +static int backend_on_initwait(struct xen_drm_front_info *front_info) +{ + return 0; +} + +static int backend_on_connected(struct xen_drm_front_info *front_info) +{ + return 0; +} + +static void backend_on_disconnected(struct xen_drm_front_info *front_info) +{ + xenbus_switch_state(front_info->xb_dev, XenbusStateInitialising); +} + static void backend_on_changed(struct xenbus_device *xb_dev, enum xenbus_state backend_state) { + struct xen_drm_front_info *front_info = dev_get_drvdata(&xb_dev->dev); + int ret; + + DRM_DEBUG("Backend state is %s, front is %s\n", + xenbus_strstate(backend_state), + xenbus_strstate(xb_dev->state)); + + switch (backend_state) { + case XenbusStateReconfiguring: + /* fall through */ + case XenbusStateReconfigured: + /* fall through */ + case XenbusStateInitialised: + break; + + case XenbusStateInitialising: + /* recovering after backend unexpected closure */ + backend_on_disconnected(front_info); + break; + + case XenbusStateInitWait: + /* recovering after backend unexpected closure */ + backend_on_disconnected(front_info); + if (xb_dev->state != XenbusStateInitialising) + break; + + ret = backend_on_initwait(front_info); + if (ret < 0) + xenbus_dev_fatal(xb_dev, ret, "initializing frontend"); + else + xenbus_switch_state(xb_dev, XenbusStateInitialised); + break; + + case XenbusStateConnected: + if (xb_dev->state != XenbusStateInitialised) + break; + + ret = backend_on_connected(front_info); + if (ret < 0) + xenbus_dev_fatal(xb_dev, ret, "initializing DRM driver"); + else + xenbus_switch_state(xb_dev, XenbusStateConnected); + break; + + case XenbusStateClosing: + /* + * in this state backend starts freeing resources, + * so let it go into closed state, so we can also + * remove ours + */ + break; + + case XenbusStateUnknown: + /* fall through */ + case XenbusStateClosed: + if (xb_dev->state == XenbusStateClosed) + break; + + backend_on_disconnected(front_info); + break; + } } static int xen_drv_probe(struct xenbus_device *xb_dev, const struct xenbus_device_id *id) { - return 0; + struct xen_drm_front_info *front_info; + + front_info = devm_kzalloc(&xb_dev->dev, + sizeof(*front_info), GFP_KERNEL); + if (!front_info) { + xenbus_dev_fatal(xb_dev, -ENOMEM, "allocating device memory"); + return -ENOMEM; + } + + front_info->xb_dev = xb_dev; + dev_set_drvdata(&xb_dev->dev, front_info); + return xenbus_switch_state(xb_dev, XenbusStateInitialising); } static int xen_drv_remove(struct xenbus_device *dev) { + struct xen_drm_front_info *front_info = dev_get_drvdata(&dev->dev); + int to = 100; + + xenbus_switch_state(dev, XenbusStateClosing); + + /* + * On driver removal it is disconnected from XenBus, + * so no backend state change events come via .otherend_changed + * callback. This prevents us from exiting gracefully, e.g. + * signaling the backend to free event channels, waiting for its + * state to change to XenbusStateClosed and cleaning at our end. + * Normally when front driver removed backend will finally go into + * XenbusStateInitWait state. + * + * Workaround: read backend's state manually and wait with time-out. + */ + while ((xenbus_read_unsigned(front_info->xb_dev->otherend, + "state", XenbusStateUnknown) != XenbusStateInitWait) && + to--) + msleep(10); + + if (!to) + DRM_ERROR("Backend state is %s while removing driver\n", + xenbus_strstate(xenbus_read_unsigned( + front_info->xb_dev->otherend, + "state", XenbusStateUnknown))); + + xen_drv_remove_internal(front_info); + xenbus_frontend_closed(dev); return 0; } diff --git a/drivers/gpu/drm/xen/xen_drm_front.h b/drivers/gpu/drm/xen/xen_drm_front.h new file mode 100644 index 000000000000..8af46850f126 --- /dev/null +++ b/drivers/gpu/drm/xen/xen_drm_front.h @@ -0,0 +1,26 @@ +/* + * Xen para-virtual DRM device + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Copyright (C) 2016-2018 EPAM Systems Inc. + * + * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> + */ + +#ifndef __XEN_DRM_FRONT_H_ +#define __XEN_DRM_FRONT_H_ + +struct xen_drm_front_info { + struct xenbus_device *xb_dev; +}; + +#endif /* __XEN_DRM_FRONT_H_ */