| Message ID | 1435641851-27295-3-git-send-email-architt@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 06/30/2015 07:24 AM, Archit Taneja wrote: > mipi_dsi_devices are inherently aware of their host because they > share a parent-child hierarchy in the device tree. > > Non-dsi drivers that create a dummy dsi device don't have this data. > In order to get this information, they require to a phandle to the dsi > host in the device tree. > > Maintain a list of all the hosts DSI that are currently registered. > > This list will be used to find the mipi_dsi_host corresponding to the > device_node passed in of_find_mipi_dsi_host_by_node. The lock protects only the list, there is no guarantee that mipi_dsi_host returned by of_find_mipi_dsi_host_by_node is still valid, or will be valid long enough. But this issue affects many kernel frameworks so I am not sure if it should block this particular patch. Reviewed-by: Andrzej Hajda <a.hajda@samsung.com> Regards Andrzej > > Signed-off-by: Archit Taneja <architt@codeaurora.org> > --- > drivers/gpu/drm/drm_mipi_dsi.c | 30 ++++++++++++++++++++++++++++++ > include/drm/drm_mipi_dsi.h | 2 ++ > 2 files changed, 32 insertions(+) > > diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c > index 9bfe215..81ddb73 100644 > --- a/drivers/gpu/drm/drm_mipi_dsi.c > +++ b/drivers/gpu/drm/drm_mipi_dsi.c > @@ -239,6 +239,28 @@ struct mipi_dsi_device *mipi_dsi_new_dummy(struct mipi_dsi_host *host, u32 reg) > return dsi; > } > > +static DEFINE_MUTEX(host_lock); > +static LIST_HEAD(host_list); > + > +struct mipi_dsi_host *of_find_mipi_dsi_host_by_node(struct device_node *node) > +{ > + struct mipi_dsi_host *host; > + > + mutex_lock(&host_lock); > + > + list_for_each_entry(host, &host_list, list) { > + if (host->dev->of_node == node) { > + mutex_unlock(&host_lock); > + return host; > + } > + } > + > + mutex_unlock(&host_lock); > + > + return NULL; > +} > +EXPORT_SYMBOL(of_find_mipi_dsi_host_by_node); > + > int mipi_dsi_host_register(struct mipi_dsi_host *host) > { > struct device_node *node; > @@ -250,6 +272,10 @@ int mipi_dsi_host_register(struct mipi_dsi_host *host) > of_mipi_dsi_device_add(host, node); > } > > + mutex_lock(&host_lock); > + list_add_tail(&host->list, &host_list); > + mutex_unlock(&host_lock); > + > return 0; > } > EXPORT_SYMBOL(mipi_dsi_host_register); > @@ -266,6 +292,10 @@ static int mipi_dsi_remove_device_fn(struct device *dev, void *priv) > void mipi_dsi_host_unregister(struct mipi_dsi_host *host) > { > device_for_each_child(host->dev, NULL, mipi_dsi_remove_device_fn); > + > + mutex_lock(&host_lock); > + list_del_init(&host->list); > + mutex_unlock(&host_lock); > } > EXPORT_SYMBOL(mipi_dsi_host_unregister); > > diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h > index d06ba99..1684a0e 100644 > --- a/include/drm/drm_mipi_dsi.h > +++ b/include/drm/drm_mipi_dsi.h > @@ -100,10 +100,12 @@ struct mipi_dsi_host_ops { > struct mipi_dsi_host { > struct device *dev; > const struct mipi_dsi_host_ops *ops; > + struct list_head list; > }; > > int mipi_dsi_host_register(struct mipi_dsi_host *host); > void mipi_dsi_host_unregister(struct mipi_dsi_host *host); > +struct mipi_dsi_host *of_find_mipi_dsi_host_by_node(struct device_node *node); > > /* DSI mode flags */ >
diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c index 9bfe215..81ddb73 100644 --- a/drivers/gpu/drm/drm_mipi_dsi.c +++ b/drivers/gpu/drm/drm_mipi_dsi.c @@ -239,6 +239,28 @@ struct mipi_dsi_device *mipi_dsi_new_dummy(struct mipi_dsi_host *host, u32 reg) return dsi; } +static DEFINE_MUTEX(host_lock); +static LIST_HEAD(host_list); + +struct mipi_dsi_host *of_find_mipi_dsi_host_by_node(struct device_node *node) +{ + struct mipi_dsi_host *host; + + mutex_lock(&host_lock); + + list_for_each_entry(host, &host_list, list) { + if (host->dev->of_node == node) { + mutex_unlock(&host_lock); + return host; + } + } + + mutex_unlock(&host_lock); + + return NULL; +} +EXPORT_SYMBOL(of_find_mipi_dsi_host_by_node); + int mipi_dsi_host_register(struct mipi_dsi_host *host) { struct device_node *node; @@ -250,6 +272,10 @@ int mipi_dsi_host_register(struct mipi_dsi_host *host) of_mipi_dsi_device_add(host, node); } + mutex_lock(&host_lock); + list_add_tail(&host->list, &host_list); + mutex_unlock(&host_lock); + return 0; } EXPORT_SYMBOL(mipi_dsi_host_register); @@ -266,6 +292,10 @@ static int mipi_dsi_remove_device_fn(struct device *dev, void *priv) void mipi_dsi_host_unregister(struct mipi_dsi_host *host) { device_for_each_child(host->dev, NULL, mipi_dsi_remove_device_fn); + + mutex_lock(&host_lock); + list_del_init(&host->list); + mutex_unlock(&host_lock); } EXPORT_SYMBOL(mipi_dsi_host_unregister); diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h index d06ba99..1684a0e 100644 --- a/include/drm/drm_mipi_dsi.h +++ b/include/drm/drm_mipi_dsi.h @@ -100,10 +100,12 @@ struct mipi_dsi_host_ops { struct mipi_dsi_host { struct device *dev; const struct mipi_dsi_host_ops *ops; + struct list_head list; }; int mipi_dsi_host_register(struct mipi_dsi_host *host); void mipi_dsi_host_unregister(struct mipi_dsi_host *host); +struct mipi_dsi_host *of_find_mipi_dsi_host_by_node(struct device_node *node); /* DSI mode flags */
mipi_dsi_devices are inherently aware of their host because they share a parent-child hierarchy in the device tree. Non-dsi drivers that create a dummy dsi device don't have this data. In order to get this information, they require to a phandle to the dsi host in the device tree. Maintain a list of all the hosts DSI that are currently registered. This list will be used to find the mipi_dsi_host corresponding to the device_node passed in of_find_mipi_dsi_host_by_node. Signed-off-by: Archit Taneja <architt@codeaurora.org> --- drivers/gpu/drm/drm_mipi_dsi.c | 30 ++++++++++++++++++++++++++++++ include/drm/drm_mipi_dsi.h | 2 ++ 2 files changed, 32 insertions(+)