nand_op_parser_exec_op should use longest pattern

[Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>]

Hi All,

I just played with the new exec_op interface for the first time and
together with Boris we found a problem in the pattern table parser.

The vf610 driver uses this pattern table:

static const struct nand_op_parser vf610_nfc_op_parser = NAND_OP_PARSER(
	NAND_OP_PARSER_PATTERN(vf610_nfc_cmd,
		NAND_OP_PARSER_PAT_CMD_ELEM(true),
		NAND_OP_PARSER_PAT_ADDR_ELEM(true, 5),
		NAND_OP_PARSER_PAT_DATA_OUT_ELEM(true, PAGE_2K + OOB_MAX),
		NAND_OP_PARSER_PAT_CMD_ELEM(true),
		NAND_OP_PARSER_PAT_WAITRDY_ELEM(true)),
	NAND_OP_PARSER_PATTERN(vf610_nfc_cmd,
		NAND_OP_PARSER_PAT_CMD_ELEM(true),
		NAND_OP_PARSER_PAT_ADDR_ELEM(true, 5),
		NAND_OP_PARSER_PAT_CMD_ELEM(true),
		NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
		NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, PAGE_2K + OOB_MAX)),
	);

It has two patterns, one supposed for writing and one for reading. All elements
are optional. Now with a typical page read we'll get this:

[   33.932464] nand:     ->CMD      [0x00]
[   33.936338] nand:     ->ADDR     [5 cyc: 00 00 00 0a 00]
[   33.941755] nand:     ->CMD      [0x30]
[   33.945628] nand:     ->WAITRDY  [max 1 ms]
[   33.949909] nand:       DATA_IN  [2176 B]

Only the first four elements are executed in one go, the fifth is
exectuted separately. This is because the pattern table parser finds
that the first pattern (supposed for writing) already matches for the
first four elements and then uses it instead of realizing that the
second pattern matches the whole operation.

I have no fix for this, just wanted to let you know. It turned out that
in my case for the GPMI nand driver I probably won't need any pattern
table.

Sascha

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