linux-kernel - [PATCH] mtd: spi-nor: intel-spi: Simulate WRDI command

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Message-ID: <282e1305-fd08-e446-1a22-eb4dff78cfb4@nokia.com>
Date:   Wed, 22 Jul 2020 16:01:36 +0200
From:   Alexander Sverdlin <alexander.sverdlin@...ia.com>
To:     Tudor Ambarus <tudor.ambarus@...rochip.com>,
        Vignesh Raghavendra <vigneshr@...com>,
        linux-mtd@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, Baurzhan Ismagulov <ibr@...ers.de>
Subject: [PATCH] mtd: spi-nor: intel-spi: Simulate WRDI command

From: Alexander Sverdlin <alexander.sverdlin@...ia.com>

After spi_nor_write_disable() return code checks were introduced in the
spi-nor front end intel-spi backend stopped to work because WRDI was never
supported and always failed.

Just pretend it was sucessful and ignore the command itself. HW sequencer
shall do the right thing automatically, while with SW sequencer we cannot
do it anyway, because the only tool we had was preopcode and it makes no
sense for WRDI.

Cc: stable@...r.kernel.org
Fixes: bce679e5ae3a ("mtd: spi-nor: Check for errors after each Register Operation")
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@...ia.com>
---
 drivers/mtd/spi-nor/controllers/intel-spi.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/mtd/spi-nor/controllers/intel-spi.c b/drivers/mtd/spi-nor/controllers/intel-spi.c
index 61d2a0a..134b356 100644
--- a/drivers/mtd/spi-nor/controllers/intel-spi.c
+++ b/drivers/mtd/spi-nor/controllers/intel-spi.c
@@ -612,6 +612,14 @@ static int intel_spi_write_reg(struct spi_nor *nor, u8 opcode, const u8 *buf,
 		return 0;
 	}
 
+	/*
+	 * We hope that HW sequencer will do the right thing automatically and
+	 * with the SW seuencer we cannot use preopcode any way, so just ignore
+	 * write disable operation and pretend it was completed successfully.
+	 */
+	if (opcode == SPINOR_OP_WRDI)
+		return 0;
+
 	writel(0, ispi->base + FADDR);
 
 	/* Write the value beforehand */
-- 
2.10.2