4236505609
Require that a frame from the buffer pool is only held for the time required to populate it in the touch driver's interrupt handler. This ensures that buffers are only freed when they are not in use by the client touch driver. Bug: 139955910 Signed-off-by: Steve Pfetsch <spfetsch@google.com> Change-Id: Id7ab070d5a11dbae89292f09c0212357063d652e
113 lines
3.4 KiB
C
113 lines
3.4 KiB
C
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#ifndef TOUCH_OFFLOAD_H
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#define TOUCH_OFFLOAD_H
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#include <linux/cdev.h>
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#include <linux/mutex.h>
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#include <linux/completion.h>
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#include <uapi/input/touch_offload.h>
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/* Maximum number of channels of touch data */
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#define MAX_CHANNELS 5
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#define DEVICE_NAME "touch_offload"
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#define CLASS_NAME "touch_offload"
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/* Frame of touch data
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*
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* entry - list entry in either the free pool or the event queue
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* header - frame header, including timestamp and index
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* num_channels - number of channels in this frame
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* channel_type - data type of each channel
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* channel_data_size - size of the data in each channel
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* channel_data - raw channel data
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*/
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struct touch_offload_frame {
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struct list_head entry;
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struct TouchOffloadFrameHeader header;
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int num_channels;
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int channel_type[MAX_CHANNELS];
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__u32 channel_data_size[MAX_CHANNELS];
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__u8 *channel_data[MAX_CHANNELS];
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};
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/* Touch Offload Context
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*
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* dev - char device
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* major_num - device major number
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* cls - pointer to class associated class
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* device - pointer to associated device
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* file - char device file for ioctl interface
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* file_lock - mutex for the ioctl interface
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* file_in_use - flag indicating the ioctl interface in use by one client
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* caps - capabilities supported by the touch driver
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* config - configuration in use by the touch driver
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* coords - snapshot of the current coordinate state
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* num_buffers - size of the pool of frame buffers
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* free_pool - list of buffers available for use
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* frame_queue - list of captured frames queued for the service
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* reserved_frame - buffer ready to be filled with the next touch frame
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* read_queue - waitqueue for blocked readers
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* packed_frame - serialized frame being read by the char device client
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* packed_frame_size - size of the array pointed to by packed_frame
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* buffer_lock - mutex protecting buffer management
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* reserve_returned - indicates that the reserved buffer was released
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* hcallback - handle/pointer to driver's private callback context
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* report_cb - driver callback used to report touch events
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* offload_running - indicates whether the offload path is in use
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*/
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struct touch_offload_context {
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/* ioctl interface */
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struct cdev dev;
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int major_num;
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struct class *cls;
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struct device *device;
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struct file file;
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struct mutex file_lock;
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bool file_in_use;
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/* touch capabilities */
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struct TouchOffloadCaps caps;
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/* touch capture configuration */
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struct TouchOffloadConfig config;
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/* coordinate state */
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struct TouchOffloadCoord coords[MAX_COORDS];
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/* buffer management */
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int num_buffers;
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struct list_head free_pool;
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struct list_head frame_queue;
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struct touch_offload_frame *reserved_frame;
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wait_queue_head_t read_queue;
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char *packed_frame;
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__u32 packed_frame_size;
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struct mutex buffer_lock;
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struct completion reserve_returned;
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/* callbacks */
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void *hcallback;
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void (*report_cb)(void *hcallback,
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struct TouchOffloadIocReport *report);
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int offload_running;
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};
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/* Initialize the touch_offload driver */
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int touch_offload_init(struct touch_offload_context *context);
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/* Clean-up the touch_offload driver */
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int touch_offload_cleanup(struct touch_offload_context *context);
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/* Allocate a new empty frame from the free pool */
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int touch_offload_reserve_frame(struct touch_offload_context *context,
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struct touch_offload_frame **frame);
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/* Insert a populated frame into the queue */
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int touch_offload_queue_frame(struct touch_offload_context *context,
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struct touch_offload_frame *frame);
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#endif // TOUCH_OFFLOAD_H
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