From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oleksandr Andrushchenko Subject: [PATCH RESEND1 03/12] ALSA: vsnd: Implement Xen bus state handling Date: Mon, 7 Aug 2017 15:22:48 +0300 Message-ID: <1502108577-8099-4-git-send-email-andr2000@gmail.com> References: <1502108577-8099-1-git-send-email-andr2000@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-lf0-f66.google.com (mail-lf0-f66.google.com [209.85.215.66]) by alsa0.perex.cz (Postfix) with ESMTP id 70297267205 for ; Mon, 7 Aug 2017 14:23:07 +0200 (CEST) Received: by mail-lf0-f66.google.com with SMTP id t128so214146lff.3 for ; Mon, 07 Aug 2017 05:23:07 -0700 (PDT) In-Reply-To: <1502108577-8099-1-git-send-email-andr2000@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: alsa-devel@alsa-project.org, xen-devel@lists.xen.org, linux-kernel@vger.kernel.org Cc: andr2000@gmail.com, Oleksandr Andrushchenko , tiwai@suse.com List-Id: alsa-devel@alsa-project.org From: Oleksandr Andrushchenko Initial handling for Xen bus states: implement Xen bus state machine for the front driver according to the state diagram and recovery flow from sound para-virtualized protocol: xen/interface/io/sndif.h. Signed-off-by: Oleksandr Andrushchenko --- sound/drivers/xen-front.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) diff --git a/sound/drivers/xen-front.c b/sound/drivers/xen-front.c index 8c5de7b0e7b5..c4fd21cac3a7 100644 --- a/sound/drivers/xen-front.c +++ b/sound/drivers/xen-front.c @@ -36,9 +36,99 @@ static void xdrv_remove_internal(struct xdrv_info *drv_info) { } +static int xdrv_be_on_initwait(struct xdrv_info *drv_info) +{ + return 0; +} + +static inline int xdrv_be_on_connected(struct xdrv_info *drv_info) +{ + return 0; +} + +static inline void xdrv_be_on_disconnected(struct xdrv_info *drv_info) +{ + xdrv_remove_internal(drv_info); +} + static void xdrv_be_on_changed(struct xenbus_device *xb_dev, enum xenbus_state backend_state) { + struct xdrv_info *drv_info = dev_get_drvdata(&xb_dev->dev); + int ret; + + switch (backend_state) { + case XenbusStateReconfiguring: + /* fall through */ + case XenbusStateReconfigured: + /* fall through */ + case XenbusStateInitialised: + /* fall through */ + break; + + case XenbusStateInitialising: + if (xb_dev->state == XenbusStateInitialising) + break; + + /* recovering after backend unexpected closure */ + mutex_lock(&drv_info->mutex); + xdrv_be_on_disconnected(drv_info); + mutex_unlock(&drv_info->mutex); + xenbus_switch_state(xb_dev, XenbusStateInitialising); + break; + + case XenbusStateInitWait: + if (xb_dev->state != XenbusStateInitialising) + break; + + mutex_lock(&drv_info->mutex); + ret = xdrv_be_on_initwait(drv_info); + mutex_unlock(&drv_info->mutex); + if (ret < 0) { + xenbus_dev_fatal(xb_dev, ret, + "initializing " XENSND_DRIVER_NAME); + break; + } + + xenbus_switch_state(xb_dev, XenbusStateInitialised); + break; + + case XenbusStateConnected: + if (xb_dev->state != XenbusStateInitialised) + break; + + mutex_lock(&drv_info->mutex); + ret = xdrv_be_on_connected(drv_info); + mutex_unlock(&drv_info->mutex); + if (ret < 0) { + xenbus_dev_fatal(xb_dev, ret, + "connecting " XENSND_DRIVER_NAME); + break; + } + + xenbus_switch_state(xb_dev, XenbusStateConnected); + break; + + case XenbusStateClosing: + /* + * in this state backend starts freeing resources, + * so let it go into closed state first, so we can also + * remove ours + */ + break; + + case XenbusStateUnknown: + /* fall through */ + case XenbusStateClosed: + if (xb_dev->state == XenbusStateClosed) + break; + + mutex_lock(&drv_info->mutex); + xdrv_be_on_disconnected(drv_info); + mutex_unlock(&drv_info->mutex); + xenbus_switch_state(xb_dev, XenbusStateInitialising); + break; + } } static int xdrv_probe(struct xenbus_device *xb_dev, @@ -56,6 +146,7 @@ static int xdrv_probe(struct xenbus_device *xb_dev, spin_lock_init(&drv_info->io_lock); mutex_init(&drv_info->mutex); dev_set_drvdata(&xb_dev->dev, drv_info); + xenbus_switch_state(xb_dev, XenbusStateInitialising); return 0; } @@ -63,6 +154,7 @@ static int xdrv_remove(struct xenbus_device *dev) { struct xdrv_info *drv_info = dev_get_drvdata(&dev->dev); + xenbus_switch_state(dev, XenbusStateClosed); mutex_lock(&drv_info->mutex); xdrv_remove_internal(drv_info); mutex_unlock(&drv_info->mutex); -- 2.7.4