STRUCT S5P_MFC_CTX(9)

🎀 struct s5p_mfc_ctx(9) 🎀

okay so bestie, welcome to the Kernel API Manual — this is the page about struct s5p_mfc_ctx, and it's literally the whole personality of a single instance's context. like, everything the driver needs to remember about one running thing lives in here. it's giving "main character struct" and honestly? deserved. 💅

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✨ NAME ✨

struct s5p_mfc_ctx — this struct contains the instance context 💖

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🌸 SYNOPSIS 🌸

struct s5p_mfc_ctx {
    struct s5p_mfc_dev *dev;
    struct v4l2_fh fh;
    int num;
    int int_cond;
    int int_type;
    unsigned int int_err;
    wait_queue_head_t queue;
    const struct s5p_mfc_fmt *src_fmt;
    const struct s5p_mfc_fmt *dst_fmt;
    struct vb2_queue vq_src;
    struct vb2_queue vq_dst;
    struct list_head src_queue;
    struct list_head dst_queue;
    unsigned int src_queue_cnt;
    unsigned int dst_queue_cnt;
    enum s5p_mfc_inst_type type;
    enum s5p_mfc_inst_state state;
    int inst_no;
    int img_width;
    int img_height;
    int buf_width;
    int buf_height;
    int luma_size;
    int chroma_size;
    int chroma_size_1;
    int mv_size;
    unsigned long consumed_stream;
    unsigned int dpb_flush_flag;
    unsigned int head_processed;
    struct s5p_mfc_priv_buf bank1;
    struct s5p_mfc_priv_buf bank2;
    enum s5p_mfc_queue_state capture_state;
    enum s5p_mfc_queue_state output_state;
    struct s5p_mfc_buf src_bufs[MFC_MAX_BUFFERS];
    int src_bufs_cnt;
    struct s5p_mfc_buf dst_bufs[MFC_MAX_BUFFERS];
    int dst_bufs_cnt;
    unsigned int sequence;
    unsigned long dec_dst_flag;
    size_t dec_src_buf_size;
    int codec_mode;
    int slice_interface;
    int loop_filter_mpeg4;
    int display_delay;
    int display_delay_enable;
    int after_packed_pb;
    int sei_fp_parse;
    int pb_count;
    int total_dpb_count;
    int mv_count;
    struct s5p_mfc_priv_buf ctx;
    struct s5p_mfc_priv_buf dsc;
    struct s5p_mfc_priv_buf shm;
    struct s5p_mfc_enc_params enc_params;
    size_t enc_dst_buf_size;
    size_t luma_dpb_size;
    size_t chroma_dpb_size;
    size_t me_buffer_size;
    size_t tmv_buffer_size;
    enum v4l2_mpeg_mfc51_video_force_frame_type force_frame_type;
    struct list_head ref_queue;
    unsigned int ref_queue_cnt;
    enum v4l2_mpeg_video_multi_slice_mode slice_mode;
    union {
      unsigned int mb;
      unsigned int bits;
    } slice_size;
    const struct s5p_mfc_codec_ops *c_ops;
    struct v4l2_ctrl *ctrls[MFC_MAX_CTRLS];
    struct v4l2_ctrl_handler ctrl_handler;
    size_t scratch_buf_size;
    int is_10bit;
    int is_422;
    int stride[VB2_MAX_PLANE_COUNT];
 };

no cap, that's a lot of fields. don't panic. we're gonna go through every single one, and by the end you'll be obsessed. 🫶

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🦋 Members 🦋

🧚 the identity crisis section

• dev — pointer to the s5p_mfc_dev of the device. like, which device do you belong to, babe
• fh — a struct v4l2_fh. that's it, that's the whole vibe
• num — number of the context that this structure describes
• type — type of the instance — decoder or encoder 👑
• state — state of the context, aka what chapter of its life it's in rn
• inst_no — number of the hw instance associated with the context

💫 interrupt & waitqueue energy

• int_cond — variable used by the waitqueue
• int_type — type of the last interrupt
• int_err — error number received from MFC hw in the interrupt
• queue — waitqueue that can be used to wait for this context to finish. it's literally the "bestie r u done yet" queue 😭

🌈 formats & queues

• src_fmt — source pixelformat information
• dst_fmt — destination pixelformat information
• vq_src — vb2 queue for source buffers
• vq_dst — vb2 queue for destination buffers
• src_queue — driver internal queue for source buffers
• dst_queue — driver internal queue for destination buffers
• src_queue_cnt — number of buffers queued on the source internal queue
• dst_queue_cnt — number of buffers queued on the dest internal queue
• capture_state — state of the capture buffers queue
• output_state — state of the output buffers queue

🍓 sizes & dimensions (the measuring tape moment)

• img_width — width of the image that is decoded or encoded
• img_height — height of the image that is decoded or encoded
• buf_width — width of the buffer for processed image
• buf_height — height of the buffer for processed image
• luma_size — size of a luma plane
• chroma_size — size of a chroma plane
• chroma_size_1 — size of a chroma third plane ✨
• mv_size — size of a motion vectors buffer

💜 stream bookkeeping

• consumed_stream — number of bytes that have been used so far from the decoding buffer
• dpb_flush_flag — flag used to indicate that a DPB buffers are being flushed
• head_processed — flag mentioning whether the header data is processed completely or not
• sequence — counter for the sequence number for v4l2
• dec_dst_flag — flags for buffers queued in the hardware
• dec_src_buf_size — size of the buffer for source buffers in decoding

🎀 memory banks & buffer pools

• bank1 — handle to memory allocated for temporary buffers from memory bank 1
• bank2 — handle to memory allocated for temporary buffers from memory bank 2
• src_bufs — information on allocated source buffers
• src_bufs_cnt — number of allocated source buffers
• dst_bufs — information on allocated destination buffers
• dst_bufs_cnt — number of allocated destination buffers

🔥 codec settings (decoder side)

• codec_mode — number of codec mode used by MFC hw
• slice_interface — slice interface flag
• loop_filter_mpeg4 — loop filter for MPEG4 flag
• display_delay — value of the display delay for H264
• display_delay_enable — display delay for H264 enable flag
• after_packed_pb — flag used to track buffer when stream is in Packed PB format
• sei_fp_parse — enable/disable parsing of frame packing SEI information
• pb_count — count of the DPB buffers required by MFC hw
• total_dpb_count — count of DPB buffers with additional buffers requested by the application
• mv_count — number of MV buffers allocated for decoding

🌸 buffer handles

• ctx — context buffer information
• dsc — descriptor buffer information
• shm — shared memory buffer information

👑 encoder stuff

• enc_params — encoding parameters for MFC
• enc_dst_buf_size — size of the buffers for encoder output
• luma_dpb_size — dpb buffer size for luma
• chroma_dpb_size — dpb buffer size for chroma
• me_buffer_size — size of the motion estimation buffer
• tmv_buffer_size — size of temporal predictor motion vector buffer
• force_frame_type — encoder's frame type forcing control
• ref_queue — list of the reference buffers for encoding
• ref_queue_cnt — number of the buffers in the reference list
• slice_mode — mode of dividing frames into slices
• slice_size — slice size

💅 ops & controls

• c_ops — ops for encoding
• ctrls — array of controls, used when adding controls to the v4l2 control framework
• ctrl_handler — handler for v4l2 framework

⭐ the little extras at the bottom

• scratch_buf_size — scratch buffer size
• is_10bit — state to check 10bit support
• is_422 — state to check YUV422 10bit format
• stride — size of stride for all planes

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🫶 SEE ALSO 🫶

• Kernel file ./drivers/media/platform/samsung/s5p-mfc/s5p_mfc_common.h
• struct s5p_mfc_priv_buf(9)
• struct s5p_mfc_dev(9)

ngl bestie, if you're digging this deep you're already iconic — go read those two structs next, they're the supporting cast and they ate too 🔥

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and that's the whole page!! 💖 this lil writeup lives in ./drivers/media/platform/samsung/s5p-mfc/s5p_mfc_common.h and it's dated October 2026 — so yeah, staying current, slay. struct s5p_mfc_ctx(9) out. 🦋✨