drivers/gpu/drm/i915/i915_cmd_parser.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/i915/i915_cmd_parser.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/i915/i915_cmd_parser.c
Extension
.c
Size
50943 bytes
Lines
1625
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct drm_i915_cmd_descriptor {
	/*
	 * Flags describing how the command parser processes the command.
	 *
	 * CMD_DESC_FIXED: The command has a fixed length if this is set,
	 *                 a length mask if not set
	 * CMD_DESC_SKIP: The command is allowed but does not follow the
	 *                standard length encoding for the opcode range in
	 *                which it falls
	 * CMD_DESC_REJECT: The command is never allowed
	 * CMD_DESC_REGISTER: The command should be checked against the
	 *                    register whitelist for the appropriate ring
	 */
	u32 flags;
#define CMD_DESC_FIXED    (1<<0)
#define CMD_DESC_SKIP     (1<<1)
#define CMD_DESC_REJECT   (1<<2)
#define CMD_DESC_REGISTER (1<<3)
#define CMD_DESC_BITMASK  (1<<4)

	/*
	 * The command's unique identification bits and the bitmask to get them.
	 * This isn't strictly the opcode field as defined in the spec and may
	 * also include type, subtype, and/or subop fields.
	 */
	struct {
		u32 value;
		u32 mask;
	} cmd;

	/*
	 * The command's length. The command is either fixed length (i.e. does
	 * not include a length field) or has a length field mask. The flag
	 * CMD_DESC_FIXED indicates a fixed length. Otherwise, the command has
	 * a length mask. All command entries in a command table must include
	 * length information.
	 */
	union {
		u32 fixed;
		u32 mask;
	} length;

	/*
	 * Describes where to find a register address in the command to check
	 * against the ring's register whitelist. Only valid if flags has the
	 * CMD_DESC_REGISTER bit set.
	 *
	 * A non-zero step value implies that the command may access multiple
	 * registers in sequence (e.g. LRI), in that case step gives the
	 * distance in dwords between individual offset fields.
	 */
	struct {
		u32 offset;
		u32 mask;
		u32 step;
	} reg;

#define MAX_CMD_DESC_BITMASKS 3
	/*
	 * Describes command checks where a particular dword is masked and
	 * compared against an expected value. If the command does not match
	 * the expected value, the parser rejects it. Only valid if flags has
	 * the CMD_DESC_BITMASK bit set. Only entries where mask is non-zero
	 * are valid.
	 *
	 * If the check specifies a non-zero condition_mask then the parser
	 * only performs the check when the bits specified by condition_mask
	 * are non-zero.
	 */
	struct {
		u32 offset;
		u32 mask;
		u32 expected;
		u32 condition_offset;
		u32 condition_mask;
	} bits[MAX_CMD_DESC_BITMASKS];
};

/*
 * A table of commands requiring special handling by the command parser.
 *
 * Each engine has an array of tables. Each table consists of an array of
 * command descriptors, which must be sorted with command opcodes in
 * ascending order.
 */
struct drm_i915_cmd_table {
	const struct drm_i915_cmd_descriptor *table;
	int count;
};

Annotation

Implementation Notes