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From:   dregan@broadcom.com
To:     dregan@broadcom.com, bcm-kernel-feedback-list@broadcom.com,
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        rafal@milecki.pl, joel.peshkin@broadcom.com,
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        bbrezillon@kernel.org, kdasu.kdev@gmail.com,
        JaimeLiao <jaimeliao.tw@gmail.com>,
        Adam Borowski <kilobyte@angband.pl>
Subject: [PATCH v4 1/4] mtd: rawnand: Add destructive operation
Date:   Mon, 23 Oct 2023 10:14:41 -0700
Message-Id: <20231023171444.322311-1-dregan@broadcom.com>
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From: Boris Brezillon <bbrezillon@kernel.org>

Erase and program operations need the write protect (wp) pin to be
de-asserted to take effect. Add the concept of destructive
operation and pass the information to exec_op() so controllers know
when they should de-assert this pin without having to decode
the command opcode.

Signed-off-by: Boris Brezillon <bbrezillon@kernel.org>
Signed-off-by: David Regan <dregan@broadcom.com>
---
Changes in v4: none

Changes in v3: updated comments and email address

Changes in v2: gave credit to Boris Brezillon
---
 drivers/mtd/nand/raw/nand_base.c | 6 ++++--
 include/linux/mtd/rawnand.h      | 9 +++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index d4b55155aeae..47cc2c35153b 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -1494,7 +1494,8 @@ static int nand_exec_prog_page_op(struct nand_chip *chip, unsigned int page,
 			    NAND_COMMON_TIMING_NS(conf, tWB_max)),
 		NAND_OP_WAIT_RDY(NAND_COMMON_TIMING_MS(conf, tPROG_max), 0),
 	};
-	struct nand_operation op = NAND_OPERATION(chip->cur_cs, instrs);
+	struct nand_operation op = NAND_DESTRUCTIVE_OPERATION(chip->cur_cs,
+							      instrs);
 	int naddrs = nand_fill_column_cycles(chip, addrs, offset_in_page);
 
 	if (naddrs < 0)
@@ -1917,7 +1918,8 @@ int nand_erase_op(struct nand_chip *chip, unsigned int eraseblock)
 			NAND_OP_WAIT_RDY(NAND_COMMON_TIMING_MS(conf, tBERS_max),
 					 0),
 		};
-		struct nand_operation op = NAND_OPERATION(chip->cur_cs, instrs);
+		struct nand_operation op = NAND_DESTRUCTIVE_OPERATION(chip->cur_cs,
+								      instrs);
 
 		if (chip->options & NAND_ROW_ADDR_3)
 			instrs[1].ctx.addr.naddrs++;
diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
index 90a141ba2a5a..31aceda8616c 100644
--- a/include/linux/mtd/rawnand.h
+++ b/include/linux/mtd/rawnand.h
@@ -1008,6 +1008,7 @@ struct nand_op_parser {
  */
 struct nand_operation {
 	unsigned int cs;
+	bool deassert_wp;
 	const struct nand_op_instr *instrs;
 	unsigned int ninstrs;
 };
@@ -1019,6 +1020,14 @@ struct nand_operation {
 		.ninstrs = ARRAY_SIZE(_instrs),			\
 	}
 
+#define NAND_DESTRUCTIVE_OPERATION(_cs, _instrs)		\
+	{							\
+		.cs = _cs,					\
+		.deassert_wp = true,				\
+		.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);
-- 
2.37.3