mtd: nand: add ->exec_op() implementation

Introduce a new interface to instruct NAND controllers to send specific
NAND operations. The new interface takes the form of a single method
called ->exec_op(). This method is designed to replace ->cmd_ctrl(),
->cmdfunc() and ->read/write_byte/word/buf() hooks.

->exec_op() is passed a set of instructions describing the operation
to execute. Each instruction has a type (ADDR, CMD, DATA, WAITRDY)
and delay. The delay is here to help simple controllers wait enough
time between each instruction, advanced controllers with integrated
timings control can ignore these delays.

Controllers that natively support complex operations (operations
formed of several instructions) can use the NAND op parser
infrastructure. This infrastructure allows controller drivers to
describe the sequence of instructions they support (called
nand_op_pattern) and a hook for each of these supported sequences. The
core then tries to find the best match for a given NAND operation, and
calls the associated hook.

Various other helpers are also added to ease NAND controller drivers
writing.

This new interface should ease support of vendor specific operations
in that NAND manufacturer drivers now have a way to check if the
controller they are connected to supports a specific operation, and
complain or refuse to probe the NAND chip when that's not the case.

Suggested-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Miquel Raynal <miquel.raynal@free-electrons.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

1 files changed, 367 insertions, 1 deletions

diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
index f8f27c6..469dc72 100644
--- a/include/linux/mtd/rawnand.h
+++ b/include/linux/mtd/rawnand.h
@@ -735,6 +735,350 @@ struct nand_manufacturer_ops {
 };
 
 /**
+ * struct nand_op_cmd_instr - Definition of a command instruction
+ * @opcode: the command to issue in one cycle
+ */
+struct nand_op_cmd_instr {
+	u8 opcode;
+};
+
+/**
+ * struct nand_op_addr_instr - Definition of an address instruction
+ * @naddrs: length of the @addrs array
+ * @addrs: array containing the address cycles to issue
+ */
+struct nand_op_addr_instr {
+	unsigned int naddrs;
+	const u8 *addrs;
+};
+
+/**
+ * struct nand_op_data_instr - Definition of a data instruction
+ * @len: number of data bytes to move
+ * @in: buffer to fill when reading from the NAND chip
+ * @out: buffer to read from when writing to the NAND chip
+ * @force_8bit: force 8-bit access
+ *
+ * Please note that "in" and "out" are inverted from the ONFI specification
+ * and are from the controller perspective, so a "in" is a read from the NAND
+ * chip while a "out" is a write to the NAND chip.
+ */
+struct nand_op_data_instr {
+	unsigned int len;
+	union {
+		void *in;
+		const void *out;
+	} buf;
+	bool force_8bit;
+};
+
+/**
+ * struct nand_op_waitrdy_instr - Definition of a wait ready instruction
+ * @timeout_ms: maximum delay while waiting for the ready/busy pin in ms
+ */
+struct nand_op_waitrdy_instr {
+	unsigned int timeout_ms;
+};
+
+/**
+ * enum nand_op_instr_type - Definition of all instruction types
+ * @NAND_OP_CMD_INSTR: command instruction
+ * @NAND_OP_ADDR_INSTR: address instruction
+ * @NAND_OP_DATA_IN_INSTR: data in instruction
+ * @NAND_OP_DATA_OUT_INSTR: data out instruction
+ * @NAND_OP_WAITRDY_INSTR: wait ready instruction
+ */
+enum nand_op_instr_type {
+	NAND_OP_CMD_INSTR,
+	NAND_OP_ADDR_INSTR,
+	NAND_OP_DATA_IN_INSTR,
+	NAND_OP_DATA_OUT_INSTR,
+	NAND_OP_WAITRDY_INSTR,
+};
+
+/**
+ * struct nand_op_instr - Instruction object
+ * @type: the instruction type
+ * @cmd/@addr/@data/@waitrdy: extra data associated to the instruction.
+ *                            You'll have to use the appropriate element
+ *                            depending on @type
+ * @delay_ns: delay the controller should apply after the instruction has been
+ *	      issued on the bus. Most modern controllers have internal timings
+ *	      control logic, and in this case, the controller driver can ignore
+ *	      this field.
+ */
+struct nand_op_instr {
+	enum nand_op_instr_type type;
+	union {
+		struct nand_op_cmd_instr cmd;
+		struct nand_op_addr_instr addr;
+		struct nand_op_data_instr data;
+		struct nand_op_waitrdy_instr waitrdy;
+	} ctx;
+	unsigned int delay_ns;
+};
+
+/*
+ * Special handling must be done for the WAITRDY timeout parameter as it usually
+ * is either tPROG (after a prog), tR (before a read), tRST (during a reset) or
+ * tBERS (during an erase) which all of them are u64 values that cannot be
+ * divided by usual kernel macros and must be handled with the special
+ * DIV_ROUND_UP_ULL() macro.
+ */
+#define __DIVIDE(dividend, divisor) ({					\
+	sizeof(dividend) == sizeof(u32) ?				\
+		DIV_ROUND_UP(dividend, divisor) :			\
+		DIV_ROUND_UP_ULL(dividend, divisor);			\
+		})
+#define PSEC_TO_NSEC(x) __DIVIDE(x, 1000)
+#define PSEC_TO_MSEC(x) __DIVIDE(x, 1000000000)
+
+#define NAND_OP_CMD(id, ns)						\
+	{								\
+		.type = NAND_OP_CMD_INSTR,				\
+		.ctx.cmd.opcode = id,					\
+		.delay_ns = ns,						\
+	}
+
+#define NAND_OP_ADDR(ncycles, cycles, ns)				\
+	{								\
+		.type = NAND_OP_ADDR_INSTR,				\
+		.ctx.addr = {						\
+			.naddrs = ncycles,				\
+			.addrs = cycles,				\
+		},							\
+		.delay_ns = ns,						\
+	}
+
+#define NAND_OP_DATA_IN(l, b, ns)					\
+	{								\
+		.type = NAND_OP_DATA_IN_INSTR,				\
+		.ctx.data = {						\
+			.len = l,					\
+			.buf.in = b,					\
+			.force_8bit = false,				\
+		},							\
+		.delay_ns = ns,						\
+	}
+
+#define NAND_OP_DATA_OUT(l, b, ns)					\
+	{								\
+		.type = NAND_OP_DATA_OUT_INSTR,				\
+		.ctx.data = {						\
+			.len = l,					\
+			.buf.out = b,					\
+			.force_8bit = false,				\
+		},							\
+		.delay_ns = ns,						\
+	}
+
+#define NAND_OP_8BIT_DATA_IN(l, b, ns)					\
+	{								\
+		.type = NAND_OP_DATA_IN_INSTR,				\
+		.ctx.data = {						\
+			.len = l,					\
+			.buf.in = b,					\
+			.force_8bit = true,				\
+		},							\
+		.delay_ns = ns,						\
+	}
+
+#define NAND_OP_8BIT_DATA_OUT(l, b, ns)					\
+	{								\
+		.type = NAND_OP_DATA_OUT_INSTR,				\
+		.ctx.data = {						\
+			.len = l,					\
+			.buf.out = b,					\
+			.force_8bit = true,				\
+		},							\
+		.delay_ns = ns,						\
+	}
+
+#define NAND_OP_WAIT_RDY(tout_ms, ns)					\
+	{								\
+		.type = NAND_OP_WAITRDY_INSTR,				\
+		.ctx.waitrdy.timeout_ms = tout_ms,			\
+		.delay_ns = ns,						\
+	}
+
+/**
+ * struct nand_subop - a sub operation
+ * @instrs: array of instructions
+ * @ninstrs: length of the @instrs array
+ * @first_instr_start_off: offset to start from for the first instruction
+ *			   of the sub-operation
+ * @last_instr_end_off: offset to end at (excluded) for the last instruction
+ *			of the sub-operation
+ *
+ * Both @first_instr_start_off and @last_instr_end_off only apply to data or
+ * address instructions.
+ *
+ * When an operation cannot be handled as is by the NAND controller, it will
+ * be split by the parser into sub-operations which will be passed to the
+ * controller driver.
+ */
+struct nand_subop {
+	const struct nand_op_instr *instrs;
+	unsigned int ninstrs;
+	unsigned int first_instr_start_off;
+	unsigned int last_instr_end_off;
+};
+
+int nand_subop_get_addr_start_off(const struct nand_subop *subop,
+				  unsigned int op_id);
+int nand_subop_get_num_addr_cyc(const struct nand_subop *subop,
+				unsigned int op_id);
+int nand_subop_get_data_start_off(const struct nand_subop *subop,
+				  unsigned int op_id);
+int nand_subop_get_data_len(const struct nand_subop *subop,
+			    unsigned int op_id);
+
+/**
+ * struct nand_op_parser_addr_constraints - Constraints for address instructions
+ * @maxcycles: maximum number of address cycles the controller can issue in a
+ *	       single step
+ */
+struct nand_op_parser_addr_constraints {
+	unsigned int maxcycles;
+};
+
+/**
+ * struct nand_op_parser_data_constraints - Constraints for data instructions
+ * @maxlen: maximum data length that the controller can handle in a single step
+ */
+struct nand_op_parser_data_constraints {
+	unsigned int maxlen;
+};
+
+/**
+ * struct nand_op_parser_pattern_elem - One element of a pattern
+ * @type: the instructuction type
+ * @optional: whether this element of the pattern is optional or mandatory
+ * @addr/@data: address or data constraint (number of cycles or data length)
+ */
+struct nand_op_parser_pattern_elem {
+	enum nand_op_instr_type type;
+	bool optional;
+	union {
+		struct nand_op_parser_addr_constraints addr;
+		struct nand_op_parser_data_constraints data;
+	};
+};
+
+#define NAND_OP_PARSER_PAT_CMD_ELEM(_opt)			\
+	{							\
+		.type = NAND_OP_CMD_INSTR,			\
+		.optional = _opt,				\
+	}
+
+#define NAND_OP_PARSER_PAT_ADDR_ELEM(_opt, _maxcycles)		\
+	{							\
+		.type = NAND_OP_ADDR_INSTR,			\
+		.optional = _opt,				\
+		.addr.maxcycles = _maxcycles,			\
+	}
+
+#define NAND_OP_PARSER_PAT_DATA_IN_ELEM(_opt, _maxlen)		\
+	{							\
+		.type = NAND_OP_DATA_IN_INSTR,			\
+		.optional = _opt,				\
+		.data.maxlen = _maxlen,				\
+	}
+
+#define NAND_OP_PARSER_PAT_DATA_OUT_ELEM(_opt, _maxlen)		\
+	{							\
+		.type = NAND_OP_DATA_OUT_INSTR,			\
+		.optional = _opt,				\
+		.data.maxlen = _maxlen,				\
+	}
+
+#define NAND_OP_PARSER_PAT_WAITRDY_ELEM(_opt)			\
+	{							\
+		.type = NAND_OP_WAITRDY_INSTR,			\
+		.optional = _opt,				\
+	}
+
+/**
+ * struct nand_op_parser_pattern - NAND sub-operation pattern descriptor
+ * @elems: array of pattern elements
+ * @nelems: number of pattern elements in @elems array
+ * @exec: the function that will issue a sub-operation
+ *
+ * A pattern is a list of elements, each element reprensenting one instruction
+ * with its constraints. The pattern itself is used by the core to match NAND
+ * chip operation with NAND controller operations.
+ * Once a match between a NAND controller operation pattern and a NAND chip
+ * operation (or a sub-set of a NAND operation) is found, the pattern ->exec()
+ * hook is called so that the controller driver can issue the operation on the
+ * bus.
+ *
+ * Controller drivers should declare as many patterns as they support and pass
+ * this list of patterns (created with the help of the following macro) to
+ * the nand_op_parser_exec_op() helper.
+ */
+struct nand_op_parser_pattern {
+	const struct nand_op_parser_pattern_elem *elems;
+	unsigned int nelems;
+	int (*exec)(struct nand_chip *chip, const struct nand_subop *subop);
+};
+
+#define NAND_OP_PARSER_PATTERN(_exec, ...)							\
+	{											\
+		.exec = _exec,									\
+		.elems = (struct nand_op_parser_pattern_elem[]) { __VA_ARGS__ },		\
+		.nelems = sizeof((struct nand_op_parser_pattern_elem[]) { __VA_ARGS__ }) /	\
+			  sizeof(struct nand_op_parser_pattern_elem),				\
+	}
+
+/**
+ * struct nand_op_parser - NAND controller operation parser descriptor
+ * @patterns: array of supported patterns
+ * @npatterns: length of the @patterns array
+ *
+ * The parser descriptor is just an array of supported patterns which will be
+ * iterated by nand_op_parser_exec_op() everytime it tries to execute an
+ * NAND operation (or tries to determine if a specific operation is supported).
+ *
+ * It is worth mentioning that patterns will be tested in their declaration
+ * order, and the first match will be taken, so it's important to order patterns
+ * appropriately so that simple/inefficient patterns are placed at the end of
+ * the list. Usually, this is where you put single instruction patterns.
+ */
+struct nand_op_parser {
+	const struct nand_op_parser_pattern *patterns;
+	unsigned int npatterns;
+};
+
+#define NAND_OP_PARSER(...)									\
+	{											\
+		.patterns = (struct nand_op_parser_pattern[]) { __VA_ARGS__ },			\
+		.npatterns = sizeof((struct nand_op_parser_pattern[]) { __VA_ARGS__ }) /	\
+			     sizeof(struct nand_op_parser_pattern),				\
+	}
+
+/**
+ * struct nand_operation - NAND operation descriptor
+ * @instrs: array of instructions to execute
+ * @ninstrs: length of the @instrs array
+ *
+ * The actual operation structure that will be passed to chip->exec_op().
+ */
+struct nand_operation {
+	const struct nand_op_instr *instrs;
+	unsigned int ninstrs;
+};
+
+#define NAND_OPERATION(_instrs)					\
+	{							\
+		.instrs = _instrs,				\
+		.ninstrs = ARRAY_SIZE(_instrs),			\
+	}
+
+int nand_op_parser_exec_op(struct nand_chip *chip,
+			   const struct nand_op_parser *parser,
+			   const struct nand_operation *op, bool check_only);
+
+/**
  * struct nand_chip - NAND Private Flash Chip Data
  * @mtd:		MTD device registered to the MTD framework
  * @IO_ADDR_R:		[BOARDSPECIFIC] address to read the 8 I/O lines of the
@@ -760,6 +1104,10 @@ struct nand_manufacturer_ops {
  *			commands to the chip.
  * @waitfunc:		[REPLACEABLE] hardwarespecific function for wait on
  *			ready.
+ * @exec_op:		controller specific method to execute NAND operations.
+ *			This method replaces ->cmdfunc(),
+ *			->{read,write}_{buf,byte,word}(), ->dev_ready() and
+ *			->waifunc().
  * @setup_read_retry:	[FLASHSPECIFIC] flash (vendor) specific function for
  *			setting the read-retry mode. Mostly needed for MLC NAND.
  * @ecc:		[BOARDSPECIFIC] ECC control structure
@@ -859,6 +1207,9 @@ struct nand_chip {
 	void (*cmdfunc)(struct mtd_info *mtd, unsigned command, int column,
 			int page_addr);
 	int(*waitfunc)(struct mtd_info *mtd, struct nand_chip *this);
+	int (*exec_op)(struct nand_chip *chip,
+		       const struct nand_operation *op,
+		       bool check_only);
 	int (*erase)(struct mtd_info *mtd, int page);
 	int (*scan_bbt)(struct mtd_info *mtd);
 	int (*onfi_set_features)(struct mtd_info *mtd, struct nand_chip *chip,
@@ -869,7 +1220,6 @@ struct nand_chip {
 	int (*setup_data_interface)(struct mtd_info *mtd, int chipnr,
 				    const struct nand_data_interface *conf);
 
-
 	int chip_delay;
 	unsigned int options;
 	unsigned int bbt_options;
@@ -929,6 +1279,15 @@ struct nand_chip {
 	} manufacturer;
 };
 
+static inline int nand_exec_op(struct nand_chip *chip,
+			       const struct nand_operation *op)
+{
+	if (!chip->exec_op)
+		return -ENOTSUPP;
+
+	return chip->exec_op(chip, op, false);
+}
+
 extern const struct mtd_ooblayout_ops nand_ooblayout_sp_ops;
 extern const struct mtd_ooblayout_ops nand_ooblayout_lp_ops;
 
@@ -1320,4 +1679,11 @@ void nand_cleanup(struct nand_chip *chip);
 
 /* Default extended ID decoding function */
 void nand_decode_ext_id(struct nand_chip *chip);
+
+/*
+ * External helper for controller drivers that have to implement the WAITRDY
+ * instruction and have no physical pin to check it.
+ */
+int nand_soft_waitrdy(struct nand_chip *chip, unsigned long timeout_ms);
+
 #endif /* __LINUX_MTD_RAWNAND_H */