From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx2.suse.de ([195.135.220.15]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1f54O0-0005bP-7r for linux-mtd@lists.infradead.org; Sun, 08 Apr 2018 07:05:13 +0000 From: NeilBrown To: Cyrille Pitchen , Marek Vasut Date: Sun, 08 Apr 2018 17:04:44 +1000 Cc: David Woodhouse , Brian Norris , Boris Brezillon , Richard Weinberger Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] mtd: spi-nor: clear Extended Address Reg on switch to 3-byte addressing. Message-ID: <874lkmw54j.fsf@notabene.neil.brown.name> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable According to section 8.2.7 Write Extended Address Register (C5h) of the Winbond W25Q256FV data sheet (256M-BIT SPI flash) The Extended Address Register is only effective when the device is in the 3-Byte Address Mode. When the device operates in the 4-Byte Address Mode (ADS=3D1), any command with address input of A31-A24 will replace the Extended Address Register values. It is recommended to check and update the Extended Address Register if necessary when the device is switched from 4-Byte to 3-Byte Address Mode. This patch adds code to implement that recommendation. Without this, my GNUBEE-PC1 will not successfully reboot, as the Extended Address Register is left with a value of '1'. When the SOC attempts to read (in 3-byte address mode) the boot loader, it reads from the wrong location. Signed-off-by: NeilBrown =2D-- drivers/mtd/spi-nor/spi-nor.c | 10 ++++++++++ include/linux/mtd/spi-nor.h | 2 ++ 2 files changed, 12 insertions(+) diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c index d445a4d3b770..c303bf0d2982 100644 =2D-- a/drivers/mtd/spi-nor/spi-nor.c +++ b/drivers/mtd/spi-nor/spi-nor.c @@ -269,6 +269,7 @@ static inline int set_4byte(struct spi_nor *nor, const = struct flash_info *info, int status; bool need_wren =3D false; u8 cmd; + u8 val; =20 switch (JEDEC_MFR(info)) { case SNOR_MFR_MICRON: @@ -283,6 +284,15 @@ static inline int set_4byte(struct spi_nor *nor, const= struct flash_info *info, status =3D nor->write_reg(nor, cmd, NULL, 0); if (need_wren) write_disable(nor); + if (!status && !enable && + nor->read_reg(nor, SPINOR_OP_RDXA, &val, 1) =3D=3D 0 && + val !=3D 0) { + /* need to reset the Extended Address Register */ + write_enable(nor); + val =3D 0; + nor->write_reg(nor, SPINOR_OP_WRXA, &val, 1); + write_disable(nor); + } =20 return status; default: diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h index de36969eb359..42954419cfdf 100644 =2D-- a/include/linux/mtd/spi-nor.h +++ b/include/linux/mtd/spi-nor.h @@ -62,6 +62,8 @@ #define SPINOR_OP_RDCR 0x35 /* Read configuration register */ #define SPINOR_OP_RDFSR 0x70 /* Read flag status register */ #define SPINOR_OP_CLFSR 0x50 /* Clear flag status register */ +#define SPINOR_OP_RDXA 0xc8 /* Read Extended Address Register */ +#define SPINOR_OP_WRXA 0xc5 /* Write Extended Address Register */ =20 /* 4-byte address opcodes - used on Spansion and some Macronix flashes. */ #define SPINOR_OP_READ_4B 0x13 /* Read data bytes (low frequency) */ =2D-=20 2.14.0.rc0.dirty --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEG8Yp69OQ2HB7X0l6Oeye3VZigbkFAlrJvwwACgkQOeye3VZi gbkV3A/+NvOnM5VU3pW4nS9rZnQ4zrCRmGF5IqmTm95eLLRRbhMlUXymQxToVFjW wFdPvnogqaFvUnBBE/YuzLvWwuwLk4YCSt3du0fxWXAN60jCRRm2PM4ATxrYjaDK qFu4exU2aWf/BFnuNgH3ydH9uhU69b9oEc1RQ+MqRam1SLDucg1grGFsbFRVR3bV L77Q0TsxCwGqLBS7Znc+A+kUJ1M1Pq2Uw55JZhB/3178d+K0A951LjUXBLG95jjh hURozyDaJpqeWVaIHbMn2lANt2WXDC9b/fj02/8gScACcYrEfuHbGtYJAMDktX4I eO8QTPqQ1aKPlYWrUpm+etHFjoHu1n6yUSd6OP9Abg+L3B0PQrMWX3mX/AAbn/AV Gh1Mk4V3DDERZz1Yibnb9drRxK5R3X2Y3Rxbm+5Yn+5QlYeHFeg7ZOkW9iZuVA+n K7Ke7xCmeLBE6wJHO0PNHYTEJT+LNbU6XIfQoPnEiU7W1rvjdxkWXOo6ggKi3rSn N+64yqOrqj+ZqR1ndSe9GsCewxcUIcE80VvyDerxNlGepDVrQvaybANC4zFRt5hB ZVygUBI9LMdA3kKw8egve0B0ylAY0ViWIVVmA7462KlAjVZ4q8BY6KpjWlnsf3nb RCt0R4tQa5Mje2rf5kanzsYQdFSLIP61DiC6EYkynloKOPnWsBs= =S+TY -----END PGP SIGNATURE----- --=-=-=--