[PATCH v4 9/9] media: uvcvideo: Implement UVC_QUIRK_PRIVACY_DURING_STREAM

From: Ricardo Ribalda
Date: Tue Dec 15 2020 - 10:49:59 EST


Some devices, can only read the privacy_pin if the device is
streaming.

This patch implement a quirk for such devices, in order to avoid invalid
reads and/or spurious events.

Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
---
drivers/media/usb/uvc/uvc_driver.c | 97 ++++++++++++++++++++++++++----
drivers/media/usb/uvc/uvc_queue.c | 3 +
drivers/media/usb/uvc/uvcvideo.h | 6 ++
3 files changed, 94 insertions(+), 12 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index e49491250e87..61313019e226 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -7,6 +7,7 @@
*/

#include <linux/atomic.h>
+#include <linux/dmi.h>
#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/list.h>
@@ -1471,13 +1472,39 @@ static int uvc_parse_control(struct uvc_device *dev)
return 0;
}

+static bool uvc_ext_gpio_is_streaming(struct uvc_device *dev)
+{
+ struct uvc_streaming *streaming;
+
+ list_for_each_entry(streaming, &dev->streams, list) {
+ if (uvc_queue_streaming(&streaming->queue))
+ return true;
+ }
+
+ return false;
+}
+
+/* Update the cached value and return true if it has changed */
+static bool uvc_gpio_update_value(struct uvc_entity *unit, u8 *new_val)
+{
+ *new_val = gpiod_get_value(unit->gpio.gpio_privacy);
+
+ return atomic_xchg(&unit->gpio.gpio_privacy_value, *new_val) !=
+ *new_val;
+}
+
static int uvc_gpio_get_cur(struct uvc_device *dev, struct uvc_entity *entity,
u8 cs, void *data, u16 size)
{
if (cs != UVC_CT_PRIVACY_CONTROL || size < 1)
return -EINVAL;

- *(uint8_t *)data = gpiod_get_value(entity->gpio.gpio_privacy);
+ if ((dev->quirks & UVC_QUIRK_PRIVACY_DURING_STREAM) &&
+ !uvc_ext_gpio_is_streaming(dev))
+ return -EBUSY;
+
+ uvc_gpio_update_value(entity, (uint8_t *)data);
+
return 0;
}

@@ -1491,26 +1518,69 @@ static int uvc_gpio_get_info(struct uvc_device *dev, struct uvc_entity *entity,
return 0;
}

-static irqreturn_t uvc_privacy_gpio_irq(int irq, void *data)
+static struct uvc_entity *uvc_find_ext_gpio_unit(struct uvc_device *dev)
{
- struct uvc_device *dev = data;
- struct uvc_video_chain *chain;
struct uvc_entity *unit;
- u8 value;

- /* GPIO entities are always on the first chain */
- chain = list_first_entry(&dev->chains, struct uvc_video_chain, list);
list_for_each_entry(unit, &dev->entities, list) {
- if (UVC_ENTITY_TYPE(unit) != UVC_EXT_GPIO_UNIT)
- continue;
- value = gpiod_get_value(unit->gpio.gpio_privacy);
- uvc_ctrl_status_event(NULL, chain, unit->controls, &value);
- return IRQ_HANDLED;
+ if (UVC_ENTITY_TYPE(unit) == UVC_EXT_GPIO_UNIT)
+ return unit;
}

+ return unit;
+}
+
+void uvc_privacy_gpio_event(struct uvc_device *dev)
+{
+ struct uvc_entity *unit;
+ struct uvc_video_chain *chain;
+ u8 new_value;
+
+ unit = uvc_find_ext_gpio_unit(dev);
+ if (WARN_ONCE(!unit, "Unable to find entity ext_gpio_unit"))
+ return;
+
+ if (!uvc_gpio_update_value(unit, &new_value))
+ return;
+
+ /* GPIO entities are always on the first chain */
+ chain = list_first_entry(&dev->chains, struct uvc_video_chain, list);
+ uvc_ctrl_status_event(NULL, chain, unit->controls, &new_value);
+}
+
+static irqreturn_t uvc_privacy_gpio_irq(int irq, void *data)
+{
+ struct uvc_device *dev = data;
+
+ /* Ignore privacy events during streamoff */
+ if (dev->quirks & UVC_QUIRK_PRIVACY_DURING_STREAM)
+ if (!uvc_ext_gpio_is_streaming(dev))
+ return IRQ_HANDLED;
+
+ uvc_privacy_gpio_event(dev);
+
return IRQ_HANDLED;
}

+static const struct dmi_system_id privacy_valid_during_streamon[] = {
+ {
+ .ident = "HP Elite c1030 Chromebook",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Jinlon"),
+ },
+ },
+ {
+ .ident = "HP Pro c640 Chromebook",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "HP"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Dratini"),
+ },
+ },
+ { } /* terminate list */
+};
+
+
static int uvc_parse_gpio(struct uvc_device *dev)
{
struct uvc_entity *unit;
@@ -1545,6 +1615,9 @@ static int uvc_parse_gpio(struct uvc_device *dev)
if (irq == -EPROBE_DEFER)
return -EPROBE_DEFER;

+ if (dmi_check_system(privacy_valid_during_streamon))
+ dev->quirks |= UVC_QUIRK_PRIVACY_DURING_STREAM;
+
if (irq < 0)
return 0;

diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
index cd60c6c1749e..e800d491303f 100644
--- a/drivers/media/usb/uvc/uvc_queue.c
+++ b/drivers/media/usb/uvc/uvc_queue.c
@@ -337,9 +337,12 @@ int uvc_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *buf,
int uvc_queue_streamon(struct uvc_video_queue *queue, enum v4l2_buf_type type)
{
int ret;
+ struct uvc_streaming *stream = uvc_queue_to_stream(queue);

mutex_lock(&queue->mutex);
ret = vb2_streamon(&queue->queue, type);
+ if (stream->dev->quirks & UVC_QUIRK_PRIVACY_DURING_STREAM)
+ uvc_privacy_gpio_event(stream->dev);
mutex_unlock(&queue->mutex);

return ret;
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 2b5ba4b02d3a..2a95b3ed3ea8 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -6,6 +6,7 @@
#error "The uvcvideo.h header is deprecated, use linux/uvcvideo.h instead."
#endif /* __KERNEL__ */

+#include <linux/atomic.h>
#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/poll.h>
@@ -209,6 +210,7 @@
#define UVC_QUIRK_RESTORE_CTRLS_ON_INIT 0x00000400
#define UVC_QUIRK_FORCE_Y8 0x00000800
#define UVC_QUIRK_FORCE_BPP 0x00001000
+#define UVC_QUIRK_PRIVACY_DURING_STREAM 0x00002000

/* Format flags */
#define UVC_FMT_FLAG_COMPRESSED 0x00000001
@@ -359,6 +361,7 @@ struct uvc_entity {
u8 bControlSize;
u8 *bmControls;
struct gpio_desc *gpio_privacy;
+ atomic_t gpio_privacy_value;
} gpio;
};

@@ -815,6 +818,9 @@ extern const struct v4l2_file_operations uvc_fops;
int uvc_mc_register_entities(struct uvc_video_chain *chain);
void uvc_mc_cleanup_entity(struct uvc_entity *entity);

+/* Privacy gpio */
+void uvc_privacy_gpio_event(struct uvc_device *dev);
+
/* Video */
int uvc_video_init(struct uvc_streaming *stream);
int uvc_video_suspend(struct uvc_streaming *stream);
--
2.29.2.684.gfbc64c5ab5-goog