From: Michael Walle <michael@walle.cc> To: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Tudor Ambarus <tudor.ambarus@microchip.com>, Michael Walle <michael@walle.cc>, Pratyush Yadav <p.yadav@ti.com>, Miquel Raynal <miquel.raynal@bootlin.com>, Richard Weinberger <richard@nod.at>, Vignesh Raghavendra <vigneshr@ti.com> Subject: [PATCH v4 3/4] mtd: spi-nor: otp: return -EROFS if region is read-only Date: Fri, 21 May 2021 21:40:33 +0200 [thread overview] Message-ID: <20210521194034.15249-4-michael@walle.cc> (raw) In-Reply-To: <20210521194034.15249-1-michael@walle.cc> SPI NOR flashes will just ignore program commands if the OTP region is locked. Thus, a user might not notice that the intended write didn't end up in the flash. Return -EROFS to the user in this case. From what I can tell, chips/cfi_cmdset_0001.c also return this error code. One could optimize spi_nor_mtd_otp_range_is_locked() to read the status register only once and not for every OTP region, but for that we would need some more invasive changes. Given that this is one-time-programmable memory and the normal access mode is reading, we just live with the small overhead. Fixes: 069089acf88b ("mtd: spi-nor: add OTP support") Signed-off-by: Michael Walle <michael@walle.cc> --- drivers/mtd/spi-nor/otp.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c index 3898ed67ba1c..b87f96593c13 100644 --- a/drivers/mtd/spi-nor/otp.c +++ b/drivers/mtd/spi-nor/otp.c @@ -249,6 +249,31 @@ static int spi_nor_mtd_otp_info(struct mtd_info *mtd, size_t len, return ret; } +static int spi_nor_mtd_otp_range_is_locked(struct spi_nor *nor, loff_t ofs, + size_t len) +{ + const struct spi_nor_otp_ops *ops = nor->params->otp.ops; + unsigned int region; + int locked; + + if (!len) + return 0; + + /* + * If any of the affected OTP regions are locked the entire range is + * considered locked. + */ + for (region = spi_nor_otp_offset_to_region(nor, ofs); + region <= spi_nor_otp_offset_to_region(nor, ofs + len - 1); + region++) { + locked = ops->is_locked(nor, region); + if (locked) + return locked; + } + + return 0; +} + static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs, size_t total_len, size_t *retlen, const u8 *buf, bool is_write) @@ -271,6 +296,16 @@ static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs, /* don't access beyond the end */ total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) - ofs); + if (is_write) { + ret = spi_nor_mtd_otp_range_is_locked(nor, ofs, total_len); + if (ret < 0) { + goto out; + } else if (ret) { + ret = -EROFS; + goto out; + } + } + *retlen = 0; while (total_len) { /* -- 2.20.1
WARNING: multiple messages have this Message-ID (diff)
From: Michael Walle <michael@walle.cc> To: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Tudor Ambarus <tudor.ambarus@microchip.com>, Michael Walle <michael@walle.cc>, Pratyush Yadav <p.yadav@ti.com>, Miquel Raynal <miquel.raynal@bootlin.com>, Richard Weinberger <richard@nod.at>, Vignesh Raghavendra <vigneshr@ti.com> Subject: [PATCH v4 3/4] mtd: spi-nor: otp: return -EROFS if region is read-only Date: Fri, 21 May 2021 21:40:33 +0200 [thread overview] Message-ID: <20210521194034.15249-4-michael@walle.cc> (raw) In-Reply-To: <20210521194034.15249-1-michael@walle.cc> SPI NOR flashes will just ignore program commands if the OTP region is locked. Thus, a user might not notice that the intended write didn't end up in the flash. Return -EROFS to the user in this case. From what I can tell, chips/cfi_cmdset_0001.c also return this error code. One could optimize spi_nor_mtd_otp_range_is_locked() to read the status register only once and not for every OTP region, but for that we would need some more invasive changes. Given that this is one-time-programmable memory and the normal access mode is reading, we just live with the small overhead. Fixes: 069089acf88b ("mtd: spi-nor: add OTP support") Signed-off-by: Michael Walle <michael@walle.cc> --- drivers/mtd/spi-nor/otp.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c index 3898ed67ba1c..b87f96593c13 100644 --- a/drivers/mtd/spi-nor/otp.c +++ b/drivers/mtd/spi-nor/otp.c @@ -249,6 +249,31 @@ static int spi_nor_mtd_otp_info(struct mtd_info *mtd, size_t len, return ret; } +static int spi_nor_mtd_otp_range_is_locked(struct spi_nor *nor, loff_t ofs, + size_t len) +{ + const struct spi_nor_otp_ops *ops = nor->params->otp.ops; + unsigned int region; + int locked; + + if (!len) + return 0; + + /* + * If any of the affected OTP regions are locked the entire range is + * considered locked. + */ + for (region = spi_nor_otp_offset_to_region(nor, ofs); + region <= spi_nor_otp_offset_to_region(nor, ofs + len - 1); + region++) { + locked = ops->is_locked(nor, region); + if (locked) + return locked; + } + + return 0; +} + static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs, size_t total_len, size_t *retlen, const u8 *buf, bool is_write) @@ -271,6 +296,16 @@ static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs, /* don't access beyond the end */ total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) - ofs); + if (is_write) { + ret = spi_nor_mtd_otp_range_is_locked(nor, ofs, total_len); + if (ret < 0) { + goto out; + } else if (ret) { + ret = -EROFS; + goto out; + } + } + *retlen = 0; while (total_len) { /* -- 2.20.1 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/
next prev parent reply other threads:[~2021-05-21 19:40 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-21 19:40 [PATCH v4 0/4] mtd: spi-nor: otp: 4 byte mode fix and erase support Michael Walle 2021-05-21 19:40 ` Michael Walle 2021-05-21 19:40 ` [PATCH v4 1/4] mtd: spi-nor: otp: fix access to security registers in 4 byte mode Michael Walle 2021-05-21 19:40 ` Michael Walle 2021-05-31 8:27 ` Tudor.Ambarus 2021-05-31 8:27 ` Tudor.Ambarus 2021-05-21 19:40 ` [PATCH v4 2/4] mtd: spi-nor: otp: use more consistent wording Michael Walle 2021-05-21 19:40 ` Michael Walle 2021-05-31 8:28 ` Tudor.Ambarus 2021-05-31 8:28 ` Tudor.Ambarus 2021-05-21 19:40 ` Michael Walle [this message] 2021-05-21 19:40 ` [PATCH v4 3/4] mtd: spi-nor: otp: return -EROFS if region is read-only Michael Walle 2021-05-25 19:33 ` Pratyush Yadav 2021-05-25 19:33 ` Pratyush Yadav 2021-05-26 10:41 ` Michael Walle 2021-05-26 10:41 ` Michael Walle 2021-05-26 11:13 ` Pratyush Yadav 2021-05-26 11:13 ` Pratyush Yadav 2021-05-31 8:52 ` Tudor.Ambarus 2021-05-31 8:52 ` Tudor.Ambarus 2021-06-01 13:02 ` Michael Walle 2021-06-01 13:02 ` Michael Walle 2021-06-03 5:22 ` Tudor.Ambarus 2021-06-03 5:22 ` Tudor.Ambarus 2021-05-21 19:40 ` [PATCH v4 4/4] mtd: spi-nor: otp: implement erase for Winbond and similar flashes Michael Walle 2021-05-21 19:40 ` Michael Walle 2021-05-25 19:37 ` Pratyush Yadav 2021-05-25 19:37 ` Pratyush Yadav 2021-05-31 8:56 ` Tudor.Ambarus 2021-05-31 8:56 ` Tudor.Ambarus 2021-06-01 13:30 ` Michael Walle 2021-06-01 13:30 ` Michael Walle 2021-06-03 5:08 ` Tudor.Ambarus 2021-06-03 5:08 ` Tudor.Ambarus 2021-06-03 5:30 ` Tudor.Ambarus 2021-06-03 5:30 ` Tudor.Ambarus
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