This patchset implements the MTD OTP functions to allow access to the SPI
OTP data. Specific support is added for Winbond flash chips.
In the past there was already an attempt by Rahul Bedarkar to add this, but
there was no response. These patches are slightly based on his work.
https://lore.kernel.org/linux-mtd/[email protected]/
Changes since v3:
- remapped the OTP regions to a contiguous area starting at 0. The
chips/cfi_cmdset_000[12].c remap the regions, too.
- with that in place, read/write/lock/erase spanning multiple OTP
regions are possible
- picked up Tudors review remarks
- added new erase support as RFC because MTD API/ABI is still missing.
Feel free to review, but don't apply it.
Changes since v2:
- improved commit messages
- add buffer size check in spi_nor_mtd_otp_info(). just to be sure, the
buffer is hardcoded to 4k by the mtd subsys
- moved all code to otp.c
- dropped the patches introduced in v2
Changes since v1:
- added methods for Macronix and similar flashes
- added patch to cleanup/consolidate code in core.c
Michael Walle (4):
mtd: spi-nor: add OTP support
mtd: spi-nor: implement OTP support for Winbond and similar flashes
mtd: spi-nor: winbond: add OTP support to w25q32fw/jw
mtd: spi-nor: implement OTP erase for Winbond and similar flashes
drivers/mtd/spi-nor/Makefile | 1 +
drivers/mtd/spi-nor/core.c | 11 +-
drivers/mtd/spi-nor/core.h | 64 +++++
drivers/mtd/spi-nor/otp.c | 453 ++++++++++++++++++++++++++++++++++
drivers/mtd/spi-nor/winbond.c | 18 +-
include/linux/mtd/spi-nor.h | 9 +
6 files changed, 551 insertions(+), 5 deletions(-)
create mode 100644 drivers/mtd/spi-nor/otp.c
--
2.20.1
SPI flashes sometimes have a special OTP area, which can (and is) used to
store immutable properties like board serial number or vendor assigned
network hardware addresses.
The MTD subsystem already supports accessing such areas and some (non
SPI NOR) flashes already implement support for it. It differentiates
between user and factory areas. User areas can be written by the user and
factory ones are pre-programmed and locked down by the vendor, usually
containing an "electrical serial number". This patch will only add support
for the user areas.
Lay the foundation and implement the MTD callbacks for the SPI NOR and add
necessary parameters to the flash_info structure. If a flash supports OTP
it can be added by the convenience macro OTP_INFO(). Sometimes there are
individual regions, which might have individual offsets. Therefore, it is
possible to specify the starting address of the first regions as well as
the distance between two regions (e.g. Winbond devices uses this method).
Additionally, the regions might be locked down. Once locked, no further
write access is possible.
For SPI NOR flashes the OTP area is accessed like the normal memory, e.g.
by offset addressing; except that you either have to use special read/write
commands (Winbond) or you have to enter (and exit) a specific OTP mode
(Macronix, Micron).
Thus we introduce four operations to which the MTD callbacks will be
mapped: .read(), .write(), .lock() and .is_locked(). The read and the write
ops will be given an address offset to operate on while the locking ops use
regions because locking always affects a whole region. It is up to the
flash driver to implement these ops.
Signed-off-by: Michael Walle <[email protected]>
---
drivers/mtd/spi-nor/Makefile | 1 +
drivers/mtd/spi-nor/core.c | 5 +
drivers/mtd/spi-nor/core.h | 54 +++++++++
drivers/mtd/spi-nor/otp.c | 218 +++++++++++++++++++++++++++++++++++
4 files changed, 278 insertions(+)
create mode 100644 drivers/mtd/spi-nor/otp.c
diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
index 653923896205..2ed2e76ce4f1 100644
--- a/drivers/mtd/spi-nor/Makefile
+++ b/drivers/mtd/spi-nor/Makefile
@@ -12,6 +12,7 @@ spi-nor-objs += intel.o
spi-nor-objs += issi.o
spi-nor-objs += macronix.o
spi-nor-objs += micron-st.o
+spi-nor-objs += otp.o
spi-nor-objs += spansion.o
spi-nor-objs += sst.o
spi-nor-objs += winbond.o
diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 4a315cb1c4db..0c5c757fa95b 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -3009,6 +3009,8 @@ static void spi_nor_info_init_params(struct spi_nor *nor)
spi_nor_set_erase_type(&map->erase_type[i], info->sector_size,
SPINOR_OP_SE);
spi_nor_init_uniform_erase_map(map, erase_mask, params->size);
+
+ nor->params->otp.org = &info->otp_org;
}
/**
@@ -3550,6 +3552,9 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
if (ret)
return ret;
+ /* Configure OTP parameters and ops */
+ spi_nor_otp_init(nor);
+
/* Send all the required SPI flash commands to initialize device */
ret = spi_nor_init(nor);
if (ret)
diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index 4a3f7f150b5d..ec8da1243846 100644
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -187,6 +187,45 @@ struct spi_nor_locking_ops {
int (*is_locked)(struct spi_nor *nor, loff_t ofs, uint64_t len);
};
+/**
+ * struct spi_nor_otp_organization - Structure to describe the SPI NOR OTP regions
+ * @len: size of one OTP region in bytes.
+ * @base: start address of the OTP area.
+ * @offset: offset between consecutive OTP regions if there are more
+ * than one.
+ * @n_regions: number of individual OTP regions.
+ */
+struct spi_nor_otp_organization {
+ size_t len;
+ loff_t base;
+ loff_t offset;
+ unsigned int n_regions;
+};
+
+/**
+ * struct spi_nor_otp_ops - SPI NOR OTP methods
+ * @read: read from the SPI NOR OTP area.
+ * @write: write to the SPI NOR OTP area.
+ * @lock: lock an OTP region.
+ * @is_locked: check if an OTP region of the SPI NOR is locked.
+ */
+struct spi_nor_otp_ops {
+ int (*read)(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf);
+ int (*write)(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf);
+ int (*lock)(struct spi_nor *nor, unsigned int region);
+ int (*is_locked)(struct spi_nor *nor, unsigned int region);
+};
+
+/**
+ * struct spi_nor_otp - SPI NOR OTP grouping structure
+ * @org: OTP region organization
+ * @ops: OTP access ops
+ */
+struct spi_nor_otp {
+ const struct spi_nor_otp_organization *org;
+ const struct spi_nor_otp_ops *ops;
+};
+
/**
* struct spi_nor_flash_parameter - SPI NOR flash parameters and settings.
* Includes legacy flash parameters and settings that can be overwritten
@@ -208,6 +247,7 @@ struct spi_nor_locking_ops {
* higher index in the array, the higher priority.
* @erase_map: the erase map parsed from the SFDP Sector Map Parameter
* Table.
+ * @otp_info: describes the OTP regions.
* @octal_dtr_enable: enables SPI NOR octal DTR mode.
* @quad_enable: enables SPI NOR quad mode.
* @set_4byte_addr_mode: puts the SPI NOR in 4 byte addressing mode.
@@ -219,6 +259,7 @@ struct spi_nor_locking_ops {
* e.g. different opcodes, specific address calculation,
* page size, etc.
* @locking_ops: SPI NOR locking methods.
+ * @otp: SPI NOR OTP methods.
*/
struct spi_nor_flash_parameter {
u64 size;
@@ -232,6 +273,7 @@ struct spi_nor_flash_parameter {
struct spi_nor_pp_command page_programs[SNOR_CMD_PP_MAX];
struct spi_nor_erase_map erase_map;
+ struct spi_nor_otp otp;
int (*octal_dtr_enable)(struct spi_nor *nor, bool enable);
int (*quad_enable)(struct spi_nor *nor);
@@ -341,6 +383,8 @@ struct flash_info {
/* Part specific fixup hooks. */
const struct spi_nor_fixups *fixups;
+
+ const struct spi_nor_otp_organization otp_org;
};
/* Used when the "_ext_id" is two bytes at most */
@@ -393,6 +437,14 @@ struct flash_info {
.addr_width = 3, \
.flags = SPI_NOR_NO_FR | SPI_NOR_XSR_RDY,
+#define OTP_INFO(_len, _n_regions, _base, _offset) \
+ .otp_org = { \
+ .len = (_len), \
+ .base = (_base), \
+ .offset = (_offset), \
+ .n_regions = (_n_regions), \
+ },
+
/**
* struct spi_nor_manufacturer - SPI NOR manufacturer object
* @name: manufacturer name
@@ -473,6 +525,8 @@ int spi_nor_post_bfpt_fixups(struct spi_nor *nor,
const struct sfdp_bfpt *bfpt,
struct spi_nor_flash_parameter *params);
+void spi_nor_otp_init(struct spi_nor *nor);
+
static struct spi_nor __maybe_unused *mtd_to_spi_nor(struct mtd_info *mtd)
{
return mtd->priv;
diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c
new file mode 100644
index 000000000000..4e301fd5156b
--- /dev/null
+++ b/drivers/mtd/spi-nor/otp.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * OTP support for SPI NOR flashes
+ *
+ * Copyright (C) 2021 Michael Walle <[email protected]>
+ */
+
+#include <linux/log2.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/spi-nor.h>
+
+#include "core.h"
+
+#define spi_nor_otp_ops(nor) ((nor)->params->otp.ops)
+#define spi_nor_otp_region_len(nor) ((nor)->params->otp.org->len)
+#define spi_nor_otp_n_regions(nor) ((nor)->params->otp.org->n_regions)
+
+static loff_t spi_nor_otp_region_start(const struct spi_nor *nor, int region)
+{
+ const struct spi_nor_otp_organization *org = nor->params->otp.org;
+
+ return org->base + region * org->offset;
+}
+
+static size_t spi_nor_otp_size(struct spi_nor *nor)
+{
+ return spi_nor_otp_n_regions(nor) * spi_nor_otp_region_len(nor);
+}
+
+/*
+ * Translate the file offsets from and to OTP regions. See also
+ * spi_nor_mtd_otp_do_op().
+ */
+static loff_t spi_nor_otp_region_to_offset(struct spi_nor *nor, unsigned int region)
+{
+ return region * spi_nor_otp_region_len(nor);
+}
+
+static unsigned int spi_nor_otp_offset_to_region(struct spi_nor *nor, loff_t ofs)
+{
+ return ofs / spi_nor_otp_region_len(nor);
+}
+
+static int spi_nor_mtd_otp_info(struct mtd_info *mtd, size_t len,
+ size_t *retlen, struct otp_info *buf)
+{
+ struct spi_nor *nor = mtd_to_spi_nor(mtd);
+ const struct spi_nor_otp_ops *ops = spi_nor_otp_ops(nor);
+ unsigned int n_regions = spi_nor_otp_n_regions(nor);
+ unsigned int region;
+ int ret, locked;
+
+ if (len < n_regions * sizeof(*buf))
+ return -ENOSPC;
+
+ ret = spi_nor_lock_and_prep(nor);
+ if (ret)
+ return ret;
+
+ for (region = 0; region < spi_nor_otp_n_regions(nor); region++) {
+ buf->start = spi_nor_otp_region_to_offset(nor, region);
+ buf->length = spi_nor_otp_region_len(nor);
+
+ locked = ops->is_locked(nor, region);
+ if (locked < 0) {
+ ret = locked;
+ goto out;
+ }
+
+ buf->locked = !!locked;
+ buf++;
+ }
+
+ *retlen = n_regions * sizeof(*buf);
+
+out:
+ spi_nor_unlock_and_unprep(nor);
+
+ return ret;
+}
+
+static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs,
+ size_t total_len, size_t *retlen,
+ u_char *buf, bool is_write)
+{
+ struct spi_nor *nor = mtd_to_spi_nor(mtd);
+ const struct spi_nor_otp_ops *ops = spi_nor_otp_ops(nor);
+ const size_t rlen = spi_nor_otp_region_len(nor);
+ loff_t rstart, rofs;
+ unsigned int region;
+ size_t len;
+ int ret;
+
+ if (ofs < 0 || ofs >= spi_nor_otp_size(nor))
+ return 0;
+
+ ret = spi_nor_lock_and_prep(nor);
+ if (ret)
+ return ret;
+
+ /* don't access beyond the end */
+ total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) - ofs);
+
+ *retlen = 0;
+ while (total_len) {
+ /*
+ * The OTP regions are mapped into a contiguous area starting
+ * at 0 as expected by the MTD layer. This will map the MTD
+ * file offsets to the address of an OTP region as used in the
+ * actual SPI commands.
+ */
+ region = spi_nor_otp_offset_to_region(nor, ofs);
+ rstart = spi_nor_otp_region_start(nor, region);
+
+ /*
+ * The size of a OTP region is expected to be a power of two,
+ * thus we can just mask the lower bits and get the offset into
+ * a region.
+ */
+ rofs = ofs & (rlen - 1);
+
+ /* don't access beyond one OTP region */
+ len = min_t(size_t, total_len, rlen - rofs);
+
+ if (is_write)
+ ret = ops->write(nor, rstart + rofs, len, buf);
+ else
+ ret = ops->read(nor, rstart + rofs, len, buf);
+ if (ret == 0)
+ ret = -EIO;
+ if (ret < 0)
+ goto out;
+
+ *retlen += ret;
+ ofs += ret;
+ buf += ret;
+ total_len -= ret;
+ }
+ ret = 0;
+
+out:
+ spi_nor_unlock_and_unprep(nor);
+ return ret;
+}
+
+static int spi_nor_mtd_otp_read(struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf)
+{
+ return spi_nor_mtd_otp_read_write(mtd, from, len, retlen, buf, false);
+}
+
+static int spi_nor_mtd_otp_write(struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, u_char *buf)
+{
+ return spi_nor_mtd_otp_read_write(mtd, to, len, retlen, buf, true);
+}
+
+static int spi_nor_mtd_otp_lock(struct mtd_info *mtd, loff_t from, size_t len)
+{
+ struct spi_nor *nor = mtd_to_spi_nor(mtd);
+ const struct spi_nor_otp_ops *ops = spi_nor_otp_ops(nor);
+ unsigned int region;
+ int ret;
+
+ if (from < 0 || (from + len) > spi_nor_otp_size(nor))
+ return -EINVAL;
+
+ /* the user has to explicitly ask for whole regions */
+ if (len % spi_nor_otp_region_len(nor))
+ return -EINVAL;
+
+ if (from % spi_nor_otp_region_len(nor))
+ return -EINVAL;
+
+ ret = spi_nor_lock_and_prep(nor);
+ if (ret)
+ return ret;
+
+ while (len) {
+ region = spi_nor_otp_offset_to_region(nor, from);
+ ret = ops->lock(nor, region);
+ if (ret)
+ goto out;
+
+ len -= spi_nor_otp_region_len(nor);
+ from += spi_nor_otp_region_len(nor);
+ }
+
+out:
+ spi_nor_unlock_and_unprep(nor);
+
+ return ret;
+}
+
+void spi_nor_otp_init(struct spi_nor *nor)
+{
+ struct mtd_info *mtd = &nor->mtd;
+
+ if (!nor->params->otp.ops)
+ return;
+
+ if (WARN_ON(!is_power_of_2(spi_nor_otp_region_len(nor))))
+ return;
+
+ /*
+ * We only support user_prot callbacks (yet).
+ *
+ * Some SPI NOR flashes like Macronix ones can be ordered in two
+ * different variants. One with a factory locked OTP area and one where
+ * it is left to the user to write to it. The factory locked OTP is
+ * usually preprogrammed with an "electrical serial number". We don't
+ * support these for now.
+ */
+ mtd->_get_user_prot_info = spi_nor_mtd_otp_info;
+ mtd->_read_user_prot_reg = spi_nor_mtd_otp_read;
+ mtd->_write_user_prot_reg = spi_nor_mtd_otp_write;
+ mtd->_lock_user_prot_reg = spi_nor_mtd_otp_lock;
+}
--
2.20.1
With all the helper functions in place, add OTP support for the Winbond
W25Q32JW and W25Q32FW.
Both were tested on a LS1028A SoC with a NXP FSPI controller.
Signed-off-by: Michael Walle <[email protected]>
---
drivers/mtd/spi-nor/winbond.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/spi-nor/winbond.c b/drivers/mtd/spi-nor/winbond.c
index e5dfa786f190..9a3f8ff007fd 100644
--- a/drivers/mtd/spi-nor/winbond.c
+++ b/drivers/mtd/spi-nor/winbond.c
@@ -55,14 +55,18 @@ static const struct flash_info winbond_parts[] = {
{ "w25q32", INFO(0xef4016, 0, 64 * 1024, 64, SECT_4K) },
{ "w25q32dw", INFO(0xef6016, 0, 64 * 1024, 64,
SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
- SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB) },
+ SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
+ OTP_INFO(256, 3, 0x1000, 0x1000)
+ },
+
{ "w25q32jv", INFO(0xef7016, 0, 64 * 1024, 64,
SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
},
{ "w25q32jwm", INFO(0xef8016, 0, 64 * 1024, 64,
SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
- SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB) },
+ SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
+ OTP_INFO(256, 3, 0x1000, 0x1000) },
{ "w25q64jwm", INFO(0xef8017, 0, 64 * 1024, 128,
SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB) },
@@ -131,9 +135,18 @@ static int winbond_set_4byte_addr_mode(struct spi_nor *nor, bool enable)
return spi_nor_write_disable(nor);
}
+static const struct spi_nor_otp_ops winbond_otp_ops = {
+ .read = spi_nor_otp_read_secr,
+ .write = spi_nor_otp_write_secr,
+ .lock = spi_nor_otp_lock_sr2,
+ .is_locked = spi_nor_otp_is_locked_sr2,
+};
+
static void winbond_default_init(struct spi_nor *nor)
{
nor->params->set_4byte_addr_mode = winbond_set_4byte_addr_mode;
+ if (nor->params->otp.org->n_regions)
+ nor->params->otp.ops = &winbond_otp_ops;
}
static const struct spi_nor_fixups winbond_fixups = {
--
2.20.1
Michael,
Just cosmetic suggestions this time.
On 3/6/21 2:05 AM, Michael Walle wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> SPI flashes sometimes have a special OTP area, which can (and is) used to
> store immutable properties like board serial number or vendor assigned
> network hardware addresses.
>
> The MTD subsystem already supports accessing such areas and some (non
> SPI NOR) flashes already implement support for it. It differentiates
> between user and factory areas. User areas can be written by the user and
> factory ones are pre-programmed and locked down by the vendor, usually
> containing an "electrical serial number". This patch will only add support
> for the user areas.
>
> Lay the foundation and implement the MTD callbacks for the SPI NOR and add
> necessary parameters to the flash_info structure. If a flash supports OTP
> it can be added by the convenience macro OTP_INFO(). Sometimes there are
> individual regions, which might have individual offsets. Therefore, it is
> possible to specify the starting address of the first regions as well as
> the distance between two regions (e.g. Winbond devices uses this method).
>
> Additionally, the regions might be locked down. Once locked, no further
> write access is possible.
>
> For SPI NOR flashes the OTP area is accessed like the normal memory, e.g.
> by offset addressing; except that you either have to use special read/write
> commands (Winbond) or you have to enter (and exit) a specific OTP mode
> (Macronix, Micron).
>
> Thus we introduce four operations to which the MTD callbacks will be
> mapped: .read(), .write(), .lock() and .is_locked(). The read and the write
> ops will be given an address offset to operate on while the locking ops use
> regions because locking always affects a whole region. It is up to the
> flash driver to implement these ops.
>
> Signed-off-by: Michael Walle <[email protected]>
> ---
> drivers/mtd/spi-nor/Makefile | 1 +
> drivers/mtd/spi-nor/core.c | 5 +
> drivers/mtd/spi-nor/core.h | 54 +++++++++
> drivers/mtd/spi-nor/otp.c | 218 +++++++++++++++++++++++++++++++++++
> 4 files changed, 278 insertions(+)
> create mode 100644 drivers/mtd/spi-nor/otp.c
>
> diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
> index 653923896205..2ed2e76ce4f1 100644
> --- a/drivers/mtd/spi-nor/Makefile
> +++ b/drivers/mtd/spi-nor/Makefile
> @@ -12,6 +12,7 @@ spi-nor-objs += intel.o
> spi-nor-objs += issi.o
> spi-nor-objs += macronix.o
> spi-nor-objs += micron-st.o
> +spi-nor-objs += otp.o
spi-nor-objs := core.o sfdp.o otp.o
This better indicates that otp is part of the "core" driver, while
the rest are manufacturer drivers (that are too part of the core).
> spi-nor-objs += spansion.o
> spi-nor-objs += sst.o
> spi-nor-objs += winbond.o
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index 4a315cb1c4db..0c5c757fa95b 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -3009,6 +3009,8 @@ static void spi_nor_info_init_params(struct spi_nor *nor)
> spi_nor_set_erase_type(&map->erase_type[i], info->sector_size,
> SPINOR_OP_SE);
> spi_nor_init_uniform_erase_map(map, erase_mask, params->size);
> +
> + nor->params->otp.org = &info->otp_org;
Init this immediately after the setup init, something like:
params->setup = spi_nor_default_setup;
params->otp.org = &info->otp_org;
> }
>
> /**
> @@ -3550,6 +3552,9 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
> if (ret)
> return ret;
>
> + /* Configure OTP parameters and ops */
> + spi_nor_otp_init(nor);
Please move this as the last init thing in spi_nor_scan, immediately after
spi_nor_init(nor);
MTD OTP ops are not used accross spi_nor_scan(), there's no need to init
these earlier.
> +
> /* Send all the required SPI flash commands to initialize device */
> ret = spi_nor_init(nor);
> if (ret)
> diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
> index 4a3f7f150b5d..ec8da1243846 100644
> --- a/drivers/mtd/spi-nor/core.h
> +++ b/drivers/mtd/spi-nor/core.h
> @@ -187,6 +187,45 @@ struct spi_nor_locking_ops {
> int (*is_locked)(struct spi_nor *nor, loff_t ofs, uint64_t len);
> };
>
> +/**
> + * struct spi_nor_otp_organization - Structure to describe the SPI NOR OTP regions
> + * @len: size of one OTP region in bytes.
> + * @base: start address of the OTP area.
> + * @offset: offset between consecutive OTP regions if there are more
> + * than one.
> + * @n_regions: number of individual OTP regions.
> + */
> +struct spi_nor_otp_organization {
> + size_t len;
> + loff_t base;
> + loff_t offset;
> + unsigned int n_regions;
> +};
> +
> +/**
> + * struct spi_nor_otp_ops - SPI NOR OTP methods
> + * @read: read from the SPI NOR OTP area.
> + * @write: write to the SPI NOR OTP area.
> + * @lock: lock an OTP region.
> + * @is_locked: check if an OTP region of the SPI NOR is locked.
> + */
> +struct spi_nor_otp_ops {
> + int (*read)(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf);
> + int (*write)(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf);
> + int (*lock)(struct spi_nor *nor, unsigned int region);
> + int (*is_locked)(struct spi_nor *nor, unsigned int region);
> +};
> +
> +/**
> + * struct spi_nor_otp - SPI NOR OTP grouping structure
> + * @org: OTP region organization
> + * @ops: OTP access ops
> + */
> +struct spi_nor_otp {
> + const struct spi_nor_otp_organization *org;
> + const struct spi_nor_otp_ops *ops;
> +};
> +
> /**
> * struct spi_nor_flash_parameter - SPI NOR flash parameters and settings.
> * Includes legacy flash parameters and settings that can be overwritten
> @@ -208,6 +247,7 @@ struct spi_nor_locking_ops {
> * higher index in the array, the higher priority.
> * @erase_map: the erase map parsed from the SFDP Sector Map Parameter
> * Table.
> + * @otp_info: describes the OTP regions.
> * @octal_dtr_enable: enables SPI NOR octal DTR mode.
> * @quad_enable: enables SPI NOR quad mode.
> * @set_4byte_addr_mode: puts the SPI NOR in 4 byte addressing mode.
> @@ -219,6 +259,7 @@ struct spi_nor_locking_ops {
> * e.g. different opcodes, specific address calculation,
> * page size, etc.
> * @locking_ops: SPI NOR locking methods.
> + * @otp: SPI NOR OTP methods.
> */
> struct spi_nor_flash_parameter {
> u64 size;
> @@ -232,6 +273,7 @@ struct spi_nor_flash_parameter {
> struct spi_nor_pp_command page_programs[SNOR_CMD_PP_MAX];
>
> struct spi_nor_erase_map erase_map;
> + struct spi_nor_otp otp;
>
> int (*octal_dtr_enable)(struct spi_nor *nor, bool enable);
> int (*quad_enable)(struct spi_nor *nor);
> @@ -341,6 +383,8 @@ struct flash_info {
>
> /* Part specific fixup hooks. */
> const struct spi_nor_fixups *fixups;
> +
> + const struct spi_nor_otp_organization otp_org;
Can we move otp_org just before fixups? Fixups are usually the last thing
that we want to specify in a flash info.
> };
>
> /* Used when the "_ext_id" is two bytes at most */
> @@ -393,6 +437,14 @@ struct flash_info {
> .addr_width = 3, \
> .flags = SPI_NOR_NO_FR | SPI_NOR_XSR_RDY,
>
> +#define OTP_INFO(_len, _n_regions, _base, _offset) \
> + .otp_org = { \
> + .len = (_len), \
> + .base = (_base), \
> + .offset = (_offset), \
> + .n_regions = (_n_regions), \
> + },
> +
> /**
> * struct spi_nor_manufacturer - SPI NOR manufacturer object
> * @name: manufacturer name
> @@ -473,6 +525,8 @@ int spi_nor_post_bfpt_fixups(struct spi_nor *nor,
> const struct sfdp_bfpt *bfpt,
> struct spi_nor_flash_parameter *params);
>
> +void spi_nor_otp_init(struct spi_nor *nor);
> +
> static struct spi_nor __maybe_unused *mtd_to_spi_nor(struct mtd_info *mtd)
> {
> return mtd->priv;
> diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c
> new file mode 100644
> index 000000000000..4e301fd5156b
> --- /dev/null
> +++ b/drivers/mtd/spi-nor/otp.c
> @@ -0,0 +1,218 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * OTP support for SPI NOR flashes
> + *
> + * Copyright (C) 2021 Michael Walle <[email protected]>> + */
> +
> +#include <linux/log2.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/spi-nor.h>
> +
> +#include "core.h"
> +
> +#define spi_nor_otp_ops(nor) ((nor)->params->otp.ops)
> +#define spi_nor_otp_region_len(nor) ((nor)->params->otp.org->len)
> +#define spi_nor_otp_n_regions(nor) ((nor)->params->otp.org->n_regions)
I don't like these wrappers because they gratuiously hide what's really there.
I find the code more easier to read without these wrappers, because I don't
have to memorize what these wrappers are doing, and I better see how the code
is organized.
> +
> +static loff_t spi_nor_otp_region_start(const struct spi_nor *nor, int region)
> +{
> + const struct spi_nor_otp_organization *org = nor->params->otp.org;
how about s/org/otp_org?
> +
> + return org->base + region * org->offset;
> +}
> +
> +static size_t spi_nor_otp_size(struct spi_nor *nor)
> +{
> + return spi_nor_otp_n_regions(nor) * spi_nor_otp_region_len(nor);
> +}
> +
> +/*
> + * Translate the file offsets from and to OTP regions. See also
> + * spi_nor_mtd_otp_do_op().
> + */
> +static loff_t spi_nor_otp_region_to_offset(struct spi_nor *nor, unsigned int region)
> +{
> + return region * spi_nor_otp_region_len(nor);
> +}
> +
> +static unsigned int spi_nor_otp_offset_to_region(struct spi_nor *nor, loff_t ofs)
> +{
> + return ofs / spi_nor_otp_region_len(nor);
> +}
> +
> +static int spi_nor_mtd_otp_info(struct mtd_info *mtd, size_t len,
> + size_t *retlen, struct otp_info *buf)
> +{
> + struct spi_nor *nor = mtd_to_spi_nor(mtd);
> + const struct spi_nor_otp_ops *ops = spi_nor_otp_ops(nor);
> + unsigned int n_regions = spi_nor_otp_n_regions(nor);
> + unsigned int region;
> + int ret, locked;
> +
> + if (len < n_regions * sizeof(*buf))
> + return -ENOSPC;
> +
> + ret = spi_nor_lock_and_prep(nor);
> + if (ret)
> + return ret;
> +
> + for (region = 0; region < spi_nor_otp_n_regions(nor); region++) {
for (i = 0; i < n_regions; i++)
already indicates that i is the index of a region, no need to have an explicit
name. Also, if you want to introduce a local variable, n_regions, use it here
too.
> + buf->start = spi_nor_otp_region_to_offset(nor, region);
> + buf->length = spi_nor_otp_region_len(nor);
> +
> + locked = ops->is_locked(nor, region);
> + if (locked < 0) {
> + ret = locked;
> + goto out;
> + }
> +
> + buf->locked = !!locked;
> + buf++;
> + }
> +
> + *retlen = n_regions * sizeof(*buf);
> +
> +out:
> + spi_nor_unlock_and_unprep(nor);
> +
> + return ret;
> +}
> +
> +static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs,
> + size_t total_len, size_t *retlen,
> + u_char *buf, bool is_write)
not related to this patch, but the list of arguments is quite big, maybe
we can update mtd to pass a pointer to a struct.
> +{
> + struct spi_nor *nor = mtd_to_spi_nor(mtd);
> + const struct spi_nor_otp_ops *ops = spi_nor_otp_ops(nor);
> + const size_t rlen = spi_nor_otp_region_len(nor);
> + loff_t rstart, rofs;
> + unsigned int region;
> + size_t len;
> + int ret;
> +
> + if (ofs < 0 || ofs >= spi_nor_otp_size(nor))
> + return 0;
> +
> + ret = spi_nor_lock_and_prep(nor);
> + if (ret)
> + return ret;
> +
> + /* don't access beyond the end */
> + total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) - ofs);
> +
> + *retlen = 0;
> + while (total_len) {
> + /*
> + * The OTP regions are mapped into a contiguous area starting
> + * at 0 as expected by the MTD layer. This will map the MTD
> + * file offsets to the address of an OTP region as used in the
> + * actual SPI commands.
> + */
> + region = spi_nor_otp_offset_to_region(nor, ofs);
> + rstart = spi_nor_otp_region_start(nor, region);
Maybe it's just me, but I don't like the helpers :).
Especially spi_nor_otp_offset_to_region. And spi_nor_otp_region_start()
is used just here. Maybe discard them and s/region/i?
> +
> + /*
> + * The size of a OTP region is expected to be a power of two,
> + * thus we can just mask the lower bits and get the offset into
> + * a region.
> + */
> + rofs = ofs & (rlen - 1);
> +
> + /* don't access beyond one OTP region */
> + len = min_t(size_t, total_len, rlen - rofs);
> +
> + if (is_write)
> + ret = ops->write(nor, rstart + rofs, len, buf);
> + else
> + ret = ops->read(nor, rstart + rofs, len, buf);
> + if (ret == 0)
> + ret = -EIO;
> + if (ret < 0)
> + goto out;
> +
> + *retlen += ret;
> + ofs += ret;
> + buf += ret;
> + total_len -= ret;
> + }
> + ret = 0;
> +
> +out:
> + spi_nor_unlock_and_unprep(nor);
> + return ret;
> +}
> +
> +static int spi_nor_mtd_otp_read(struct mtd_info *mtd, loff_t from, size_t len,
> + size_t *retlen, u_char *buf)
> +{
> + return spi_nor_mtd_otp_read_write(mtd, from, len, retlen, buf, false);
> +}
> +
> +static int spi_nor_mtd_otp_write(struct mtd_info *mtd, loff_t to, size_t len,
> + size_t *retlen, u_char *buf)
> +{
> + return spi_nor_mtd_otp_read_write(mtd, to, len, retlen, buf, true);
> +}
> +
> +static int spi_nor_mtd_otp_lock(struct mtd_info *mtd, loff_t from, size_t len)
> +{
> + struct spi_nor *nor = mtd_to_spi_nor(mtd);
> + const struct spi_nor_otp_ops *ops = spi_nor_otp_ops(nor);
> + unsigned int region;
> + int ret;
> +
> + if (from < 0 || (from + len) > spi_nor_otp_size(nor))
> + return -EINVAL;
> +
> + /* the user has to explicitly ask for whole regions */
> + if (len % spi_nor_otp_region_len(nor))
> + return -EINVAL;
> +
> + if (from % spi_nor_otp_region_len(nor))
> + return -EINVAL;
> +
> + ret = spi_nor_lock_and_prep(nor);
> + if (ret)
> + return ret;
> +
> + while (len) {
> + region = spi_nor_otp_offset_to_region(nor, from);
> + ret = ops->lock(nor, region);
> + if (ret)
> + goto out;
> +
> + len -= spi_nor_otp_region_len(nor);
> + from += spi_nor_otp_region_len(nor);
> + }
> +
> +out:
> + spi_nor_unlock_and_unprep(nor);
> +
> + return ret;
> +}
> +
> +void spi_nor_otp_init(struct spi_nor *nor)
> +{
> + struct mtd_info *mtd = &nor->mtd;
> +
> + if (!nor->params->otp.ops)
> + return;
> +
> + if (WARN_ON(!is_power_of_2(spi_nor_otp_region_len(nor))))
Why WARN_ON and not just a debug message?
Cheers,
ta
> + return;
> +
> + /*
> + * We only support user_prot callbacks (yet).
> + *
> + * Some SPI NOR flashes like Macronix ones can be ordered in two
> + * different variants. One with a factory locked OTP area and one where
> + * it is left to the user to write to it. The factory locked OTP is
> + * usually preprogrammed with an "electrical serial number". We don't
> + * support these for now.
> + */
> + mtd->_get_user_prot_info = spi_nor_mtd_otp_info;
> + mtd->_read_user_prot_reg = spi_nor_mtd_otp_read;
> + mtd->_write_user_prot_reg = spi_nor_mtd_otp_write;
> + mtd->_lock_user_prot_reg = spi_nor_mtd_otp_lock;
> +}
> --
> 2.20.1
>
On 3/6/21 2:05 AM, Michael Walle wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> With all the helper functions in place, add OTP support for the Winbond
> W25Q32JW and W25Q32FW.
>
> Both were tested on a LS1028A SoC with a NXP FSPI controller.
>
> Signed-off-by: Michael Walle <[email protected]>
> ---
> drivers/mtd/spi-nor/winbond.c | 17 +++++++++++++++--
> 1 file changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/winbond.c b/drivers/mtd/spi-nor/winbond.c
> index e5dfa786f190..9a3f8ff007fd 100644
> --- a/drivers/mtd/spi-nor/winbond.c
> +++ b/drivers/mtd/spi-nor/winbond.c
> @@ -55,14 +55,18 @@ static const struct flash_info winbond_parts[] = {
> { "w25q32", INFO(0xef4016, 0, 64 * 1024, 64, SECT_4K) },
> { "w25q32dw", INFO(0xef6016, 0, 64 * 1024, 64,
> SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
> - SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB) },
> + SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
> + OTP_INFO(256, 3, 0x1000, 0x1000)
> + },
> +
> { "w25q32jv", INFO(0xef7016, 0, 64 * 1024, 64,
> SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
> SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
> },
> { "w25q32jwm", INFO(0xef8016, 0, 64 * 1024, 64,
> SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
> - SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB) },
> + SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
> + OTP_INFO(256, 3, 0x1000, 0x1000) },
> { "w25q64jwm", INFO(0xef8017, 0, 64 * 1024, 128,
> SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
> SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB) },
> @@ -131,9 +135,18 @@ static int winbond_set_4byte_addr_mode(struct spi_nor *nor, bool enable)
> return spi_nor_write_disable(nor);
> }
>
> +static const struct spi_nor_otp_ops winbond_otp_ops = {
> + .read = spi_nor_otp_read_secr,
> + .write = spi_nor_otp_write_secr,
> + .lock = spi_nor_otp_lock_sr2,
> + .is_locked = spi_nor_otp_is_locked_sr2,
> +};
Should we have this in otp.c? It can be shared with gigadevice as well
as far as I understood.
Cheers,
ta
> +
> static void winbond_default_init(struct spi_nor *nor)
> {
> nor->params->set_4byte_addr_mode = winbond_set_4byte_addr_mode;
> + if (nor->params->otp.org->n_regions)
> + nor->params->otp.ops = &winbond_otp_ops;
> }
>
> static const struct spi_nor_fixups winbond_fixups = {
> --
> 2.20.1
>
Am 2021-03-15 08:28, schrieb [email protected]:
> Michael,
>
> Just cosmetic suggestions this time.
>
> On 3/6/21 2:05 AM, Michael Walle wrote:
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know
>> the content is safe
>>
>> SPI flashes sometimes have a special OTP area, which can (and is) used
>> to
>> store immutable properties like board serial number or vendor assigned
>> network hardware addresses.
>>
>> The MTD subsystem already supports accessing such areas and some (non
>> SPI NOR) flashes already implement support for it. It differentiates
>> between user and factory areas. User areas can be written by the user
>> and
>> factory ones are pre-programmed and locked down by the vendor, usually
>> containing an "electrical serial number". This patch will only add
>> support
>> for the user areas.
>>
>> Lay the foundation and implement the MTD callbacks for the SPI NOR and
>> add
>> necessary parameters to the flash_info structure. If a flash supports
>> OTP
>> it can be added by the convenience macro OTP_INFO(). Sometimes there
>> are
>> individual regions, which might have individual offsets. Therefore, it
>> is
>> possible to specify the starting address of the first regions as well
>> as
>> the distance between two regions (e.g. Winbond devices uses this
>> method).
>>
>> Additionally, the regions might be locked down. Once locked, no
>> further
>> write access is possible.
>>
>> For SPI NOR flashes the OTP area is accessed like the normal memory,
>> e.g.
>> by offset addressing; except that you either have to use special
>> read/write
>> commands (Winbond) or you have to enter (and exit) a specific OTP mode
>> (Macronix, Micron).
>>
>> Thus we introduce four operations to which the MTD callbacks will be
>> mapped: .read(), .write(), .lock() and .is_locked(). The read and the
>> write
>> ops will be given an address offset to operate on while the locking
>> ops use
>> regions because locking always affects a whole region. It is up to the
>> flash driver to implement these ops.
>>
>> Signed-off-by: Michael Walle <[email protected]>
>> ---
>> drivers/mtd/spi-nor/Makefile | 1 +
>> drivers/mtd/spi-nor/core.c | 5 +
>> drivers/mtd/spi-nor/core.h | 54 +++++++++
>> drivers/mtd/spi-nor/otp.c | 218
>> +++++++++++++++++++++++++++++++++++
>> 4 files changed, 278 insertions(+)
>> create mode 100644 drivers/mtd/spi-nor/otp.c
>>
>> diff --git a/drivers/mtd/spi-nor/Makefile
>> b/drivers/mtd/spi-nor/Makefile
>> index 653923896205..2ed2e76ce4f1 100644
>> --- a/drivers/mtd/spi-nor/Makefile
>> +++ b/drivers/mtd/spi-nor/Makefile
>> @@ -12,6 +12,7 @@ spi-nor-objs += intel.o
>> spi-nor-objs += issi.o
>> spi-nor-objs += macronix.o
>> spi-nor-objs += micron-st.o
>> +spi-nor-objs += otp.o
>
> spi-nor-objs := core.o sfdp.o otp.o
>
> This better indicates that otp is part of the "core" driver, while
> the rest are manufacturer drivers (that are too part of the core).
That is already fixed here. Didn't want to send yet another version ;)
>
>> spi-nor-objs += spansion.o
>> spi-nor-objs += sst.o
>> spi-nor-objs += winbond.o
>> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
>> index 4a315cb1c4db..0c5c757fa95b 100644
>> --- a/drivers/mtd/spi-nor/core.c
>> +++ b/drivers/mtd/spi-nor/core.c
>> @@ -3009,6 +3009,8 @@ static void spi_nor_info_init_params(struct
>> spi_nor *nor)
>> spi_nor_set_erase_type(&map->erase_type[i], info->sector_size,
>> SPINOR_OP_SE);
>> spi_nor_init_uniform_erase_map(map, erase_mask, params->size);
>> +
>> + nor->params->otp.org = &info->otp_org;
>
> Init this immediately after the setup init, something like:
> params->setup = spi_nor_default_setup;
> params->otp.org = &info->otp_org;
>
>> }
>>
>> /**
>> @@ -3550,6 +3552,9 @@ int spi_nor_scan(struct spi_nor *nor, const char
>> *name,
>> if (ret)
>> return ret;
>>
>> + /* Configure OTP parameters and ops */
>> + spi_nor_otp_init(nor);
>
> Please move this as the last init thing in spi_nor_scan, immediately
> after
> spi_nor_init(nor);
>
> MTD OTP ops are not used accross spi_nor_scan(), there's no need to
> init
> these earlier.
Makes sense.
>
>> +
>> /* Send all the required SPI flash commands to initialize
>> device */
>> ret = spi_nor_init(nor);
>> if (ret)
>> diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
>> index 4a3f7f150b5d..ec8da1243846 100644
>> --- a/drivers/mtd/spi-nor/core.h
>> +++ b/drivers/mtd/spi-nor/core.h
>> @@ -187,6 +187,45 @@ struct spi_nor_locking_ops {
>> int (*is_locked)(struct spi_nor *nor, loff_t ofs, uint64_t
>> len);
>> };
>>
>> +/**
>> + * struct spi_nor_otp_organization - Structure to describe the SPI
>> NOR OTP regions
>> + * @len: size of one OTP region in bytes.
>> + * @base: start address of the OTP area.
>> + * @offset: offset between consecutive OTP regions if there are
>> more
>> + * than one.
>> + * @n_regions: number of individual OTP regions.
>> + */
>> +struct spi_nor_otp_organization {
>> + size_t len;
>> + loff_t base;
>> + loff_t offset;
>> + unsigned int n_regions;
>> +};
>> +
>> +/**
>> + * struct spi_nor_otp_ops - SPI NOR OTP methods
>> + * @read: read from the SPI NOR OTP area.
>> + * @write: write to the SPI NOR OTP area.
>> + * @lock: lock an OTP region.
>> + * @is_locked: check if an OTP region of the SPI NOR is locked.
>> + */
>> +struct spi_nor_otp_ops {
>> + int (*read)(struct spi_nor *nor, loff_t addr, size_t len, u8
>> *buf);
>> + int (*write)(struct spi_nor *nor, loff_t addr, size_t len, u8
>> *buf);
>> + int (*lock)(struct spi_nor *nor, unsigned int region);
>> + int (*is_locked)(struct spi_nor *nor, unsigned int region);
>> +};
>> +
>> +/**
>> + * struct spi_nor_otp - SPI NOR OTP grouping structure
>> + * @org: OTP region organization
>> + * @ops: OTP access ops
>> + */
>> +struct spi_nor_otp {
>> + const struct spi_nor_otp_organization *org;
>> + const struct spi_nor_otp_ops *ops;
>> +};
>> +
>> /**
>> * struct spi_nor_flash_parameter - SPI NOR flash parameters and
>> settings.
>> * Includes legacy flash parameters and settings that can be
>> overwritten
>> @@ -208,6 +247,7 @@ struct spi_nor_locking_ops {
>> * higher index in the array, the higher
>> priority.
>> * @erase_map: the erase map parsed from the SFDP Sector Map
>> Parameter
>> * Table.
>> + * @otp_info: describes the OTP regions.
>> * @octal_dtr_enable: enables SPI NOR octal DTR mode.
>> * @quad_enable: enables SPI NOR quad mode.
>> * @set_4byte_addr_mode: puts the SPI NOR in 4 byte addressing mode.
>> @@ -219,6 +259,7 @@ struct spi_nor_locking_ops {
>> * e.g. different opcodes, specific address
>> calculation,
>> * page size, etc.
>> * @locking_ops: SPI NOR locking methods.
>> + * @otp: SPI NOR OTP methods.
>> */
>> struct spi_nor_flash_parameter {
>> u64 size;
>> @@ -232,6 +273,7 @@ struct spi_nor_flash_parameter {
>> struct spi_nor_pp_command
>> page_programs[SNOR_CMD_PP_MAX];
>>
>> struct spi_nor_erase_map erase_map;
>> + struct spi_nor_otp otp;
>>
>> int (*octal_dtr_enable)(struct spi_nor *nor, bool enable);
>> int (*quad_enable)(struct spi_nor *nor);
>> @@ -341,6 +383,8 @@ struct flash_info {
>>
>> /* Part specific fixup hooks. */
>> const struct spi_nor_fixups *fixups;
>> +
>> + const struct spi_nor_otp_organization otp_org;
>
> Can we move otp_org just before fixups? Fixups are usually the last
> thing
> that we want to specify in a flash info.
sure.
>> };
>>
>> /* Used when the "_ext_id" is two bytes at most */
>> @@ -393,6 +437,14 @@ struct flash_info {
>> .addr_width = 3,
>> \
>> .flags = SPI_NOR_NO_FR | SPI_NOR_XSR_RDY,
>>
>> +#define OTP_INFO(_len, _n_regions, _base, _offset)
>> \
>> + .otp_org = {
>> \
>> + .len = (_len),
>> \
>> + .base = (_base),
>> \
>> + .offset = (_offset),
>> \
>> + .n_regions = (_n_regions),
>> \
>> + },
>> +
>> /**
>> * struct spi_nor_manufacturer - SPI NOR manufacturer object
>> * @name: manufacturer name
>> @@ -473,6 +525,8 @@ int spi_nor_post_bfpt_fixups(struct spi_nor *nor,
>> const struct sfdp_bfpt *bfpt,
>> struct spi_nor_flash_parameter *params);
>>
>> +void spi_nor_otp_init(struct spi_nor *nor);
>> +
>> static struct spi_nor __maybe_unused *mtd_to_spi_nor(struct mtd_info
>> *mtd)
>> {
>> return mtd->priv;
>> diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c
>> new file mode 100644
>> index 000000000000..4e301fd5156b
>> --- /dev/null
>> +++ b/drivers/mtd/spi-nor/otp.c
>> @@ -0,0 +1,218 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * OTP support for SPI NOR flashes
>> + *
>> + * Copyright (C) 2021 Michael Walle <[email protected]>> + */
>> +
>> +#include <linux/log2.h>
>> +#include <linux/mtd/mtd.h>
>> +#include <linux/mtd/spi-nor.h>
>> +
>> +#include "core.h"
>> +
>> +#define spi_nor_otp_ops(nor) ((nor)->params->otp.ops)
>> +#define spi_nor_otp_region_len(nor) ((nor)->params->otp.org->len)
>> +#define spi_nor_otp_n_regions(nor)
>> ((nor)->params->otp.org->n_regions)
>
> I don't like these wrappers because they gratuiously hide what's really
> there.
> I find the code more easier to read without these wrappers, because I
> don't
> have to memorize what these wrappers are doing, and I better see how
> the code
> is organized.
TBH I find it easier on the eye and I've never seen so much dereferences
as in mtd/spi-nor.
>> +
>> +static loff_t spi_nor_otp_region_start(const struct spi_nor *nor, int
>> region)
>> +{
>> + const struct spi_nor_otp_organization *org =
>> nor->params->otp.org;
>
> how about s/org/otp_org?
Yeah, as it is just a one line function, I don't really care ;)
>> +
>> + return org->base + region * org->offset;
>> +}
>> +
>> +static size_t spi_nor_otp_size(struct spi_nor *nor)
>> +{
>> + return spi_nor_otp_n_regions(nor) *
>> spi_nor_otp_region_len(nor);
>> +}
>> +
>> +/*
>> + * Translate the file offsets from and to OTP regions. See also
>> + * spi_nor_mtd_otp_do_op().
>> + */
>> +static loff_t spi_nor_otp_region_to_offset(struct spi_nor *nor,
>> unsigned int region)
>> +{
>> + return region * spi_nor_otp_region_len(nor);
>> +}
>> +
>> +static unsigned int spi_nor_otp_offset_to_region(struct spi_nor *nor,
>> loff_t ofs)
>> +{
>> + return ofs / spi_nor_otp_region_len(nor);
>> +}
>> +
>> +static int spi_nor_mtd_otp_info(struct mtd_info *mtd, size_t len,
>> + size_t *retlen, struct otp_info *buf)
>> +{
>> + struct spi_nor *nor = mtd_to_spi_nor(mtd);
>> + const struct spi_nor_otp_ops *ops = spi_nor_otp_ops(nor);
>> + unsigned int n_regions = spi_nor_otp_n_regions(nor);
>> + unsigned int region;
>> + int ret, locked;
>> +
>> + if (len < n_regions * sizeof(*buf))
>> + return -ENOSPC;
>> +
>> + ret = spi_nor_lock_and_prep(nor);
>> + if (ret)
>> + return ret;
>> +
>> + for (region = 0; region < spi_nor_otp_n_regions(nor);
>> region++) {
>
> for (i = 0; i < n_regions; i++)
>
> already indicates that i is the index of a region, no need to have an
> explicit
> name. Also, if you want to introduce a local variable, n_regions, use
> it here
> too.
Mh, thas was a left over, from when I had a for_each_ helper. But the
new version just has this one occurence, so I've removed that. I
already felt there was some resistance on these helpers ;)
>
>> + buf->start = spi_nor_otp_region_to_offset(nor,
>> region);
>> + buf->length = spi_nor_otp_region_len(nor);
>> +
>> + locked = ops->is_locked(nor, region);
>> + if (locked < 0) {
>> + ret = locked;
>> + goto out;
>> + }
>> +
>> + buf->locked = !!locked;
>> + buf++;
>> + }
>> +
>> + *retlen = n_regions * sizeof(*buf);
>> +
>> +out:
>> + spi_nor_unlock_and_unprep(nor);
>> +
>> + return ret;
>> +}
>> +
>> +static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t
>> ofs,
>> + size_t total_len, size_t
>> *retlen,
>> + u_char *buf, bool is_write)
>
> not related to this patch, but the list of arguments is quite big,
> maybe
> we can update mtd to pass a pointer to a struct.
For external functions, sure. But this is internal so I don't
see any advantage here. Also this is kinda special because its
the argument list of the mtd ops appended with the is_write
parameter.
>> +{
>> + struct spi_nor *nor = mtd_to_spi_nor(mtd);
>> + const struct spi_nor_otp_ops *ops = spi_nor_otp_ops(nor);
>> + const size_t rlen = spi_nor_otp_region_len(nor);
>> + loff_t rstart, rofs;
>> + unsigned int region;
>> + size_t len;
>> + int ret;
>> +
>> + if (ofs < 0 || ofs >= spi_nor_otp_size(nor))
>> + return 0;
>> +
>> + ret = spi_nor_lock_and_prep(nor);
>> + if (ret)
>> + return ret;
>> +
>> + /* don't access beyond the end */
>> + total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) -
>> ofs);
>> +
>> + *retlen = 0;
>> + while (total_len) {
>> + /*
>> + * The OTP regions are mapped into a contiguous area
>> starting
>> + * at 0 as expected by the MTD layer. This will map
>> the MTD
>> + * file offsets to the address of an OTP region as
>> used in the
>> + * actual SPI commands.
>> + */
>> + region = spi_nor_otp_offset_to_region(nor, ofs);
>> + rstart = spi_nor_otp_region_start(nor, region);
>
> Maybe it's just me, but I don't like the helpers :).
> Especially spi_nor_otp_offset_to_region.
Ha, I actually had this open coded. But in the end, I wanted to
keep the translation from MTD offsets to OTP offsets in one place.
That is spi_nor_otp_region_to_offset() and
spi_nor_otp_offset_to_region().
> And spi_nor_otp_region_start()
> is used just here. Maybe discard them and s/region/i?
I'm not sure what you mean by use i? Here is no for loop.
And regarding the helper, it is used in 4/4 again. So it is
quite handy ;)
>> +
>> + /*
>> + * The size of a OTP region is expected to be a power
>> of two,
>> + * thus we can just mask the lower bits and get the
>> offset into
>> + * a region.
>> + */
>> + rofs = ofs & (rlen - 1);
>> +
>> + /* don't access beyond one OTP region */
>> + len = min_t(size_t, total_len, rlen - rofs);
>> +
>> + if (is_write)
>> + ret = ops->write(nor, rstart + rofs, len,
>> buf);
>> + else
>> + ret = ops->read(nor, rstart + rofs, len, buf);
>> + if (ret == 0)
>> + ret = -EIO;
>> + if (ret < 0)
>> + goto out;
>> +
>> + *retlen += ret;
>> + ofs += ret;
>> + buf += ret;
>> + total_len -= ret;
>> + }
>> + ret = 0;
>> +
>> +out:
>> + spi_nor_unlock_and_unprep(nor);
>> + return ret;
>> +}
>> +
>> +static int spi_nor_mtd_otp_read(struct mtd_info *mtd, loff_t from,
>> size_t len,
>> + size_t *retlen, u_char *buf)
>> +{
>> + return spi_nor_mtd_otp_read_write(mtd, from, len, retlen, buf,
>> false);
>> +}
>> +
>> +static int spi_nor_mtd_otp_write(struct mtd_info *mtd, loff_t to,
>> size_t len,
>> + size_t *retlen, u_char *buf)
>> +{
>> + return spi_nor_mtd_otp_read_write(mtd, to, len, retlen, buf,
>> true);
>> +}
>> +
>> +static int spi_nor_mtd_otp_lock(struct mtd_info *mtd, loff_t from,
>> size_t len)
>> +{
>> + struct spi_nor *nor = mtd_to_spi_nor(mtd);
>> + const struct spi_nor_otp_ops *ops = spi_nor_otp_ops(nor);
>> + unsigned int region;
>> + int ret;
>> +
>> + if (from < 0 || (from + len) > spi_nor_otp_size(nor))
>> + return -EINVAL;
>> +
>> + /* the user has to explicitly ask for whole regions */
>> + if (len % spi_nor_otp_region_len(nor))
>> + return -EINVAL;
>> +
>> + if (from % spi_nor_otp_region_len(nor))
>> + return -EINVAL;
>> +
>> + ret = spi_nor_lock_and_prep(nor);
>> + if (ret)
>> + return ret;
>> +
>> + while (len) {
>> + region = spi_nor_otp_offset_to_region(nor, from);
>> + ret = ops->lock(nor, region);
>> + if (ret)
>> + goto out;
>> +
>> + len -= spi_nor_otp_region_len(nor);
>> + from += spi_nor_otp_region_len(nor);
>> + }
>> +
>> +out:
>> + spi_nor_unlock_and_unprep(nor);
>> +
>> + return ret;
>> +}
>> +
>> +void spi_nor_otp_init(struct spi_nor *nor)
>> +{
>> + struct mtd_info *mtd = &nor->mtd;
>> +
>> + if (!nor->params->otp.ops)
>> + return;
>> +
>> + if (WARN_ON(!is_power_of_2(spi_nor_otp_region_len(nor))))
>
> Why WARN_ON and not just a debug message?
Because it really is a programming error, but I don't want to use
BUG_ON(). That is, the developer has either used a OTP_INFO() wrong
or he wants to add a flash which isn't yet supported. I don't see
a reason to "hide" that behind a debug message. It just depends
on the static OTP configuration and can't change at runtime.
-michael
Am 2021-03-15 09:26, schrieb [email protected]:
> On 3/6/21 2:05 AM, Michael Walle wrote:
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know
>> the content is safe
>>
>> With all the helper functions in place, add OTP support for the
>> Winbond
>> W25Q32JW and W25Q32FW.
>>
>> Both were tested on a LS1028A SoC with a NXP FSPI controller.
>>
>> Signed-off-by: Michael Walle <[email protected]>
>> ---
>> drivers/mtd/spi-nor/winbond.c | 17 +++++++++++++++--
>> 1 file changed, 15 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mtd/spi-nor/winbond.c
>> b/drivers/mtd/spi-nor/winbond.c
>> index e5dfa786f190..9a3f8ff007fd 100644
>> --- a/drivers/mtd/spi-nor/winbond.c
>> +++ b/drivers/mtd/spi-nor/winbond.c
>> @@ -55,14 +55,18 @@ static const struct flash_info winbond_parts[] = {
>> { "w25q32", INFO(0xef4016, 0, 64 * 1024, 64, SECT_4K) },
>> { "w25q32dw", INFO(0xef6016, 0, 64 * 1024, 64,
>> SECT_4K | SPI_NOR_DUAL_READ |
>> SPI_NOR_QUAD_READ |
>> - SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB) },
>> + SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
>> + OTP_INFO(256, 3, 0x1000, 0x1000)
>> + },
>> +
>> { "w25q32jv", INFO(0xef7016, 0, 64 * 1024, 64,
>> SECT_4K | SPI_NOR_DUAL_READ |
>> SPI_NOR_QUAD_READ |
>> SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
>> },
>> { "w25q32jwm", INFO(0xef8016, 0, 64 * 1024, 64,
>> SECT_4K | SPI_NOR_DUAL_READ |
>> SPI_NOR_QUAD_READ |
>> - SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB) },
>> + SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
>> + OTP_INFO(256, 3, 0x1000, 0x1000) },
>> { "w25q64jwm", INFO(0xef8017, 0, 64 * 1024, 128,
>> SECT_4K | SPI_NOR_DUAL_READ |
>> SPI_NOR_QUAD_READ |
>> SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB) },
>> @@ -131,9 +135,18 @@ static int winbond_set_4byte_addr_mode(struct
>> spi_nor *nor, bool enable)
>> return spi_nor_write_disable(nor);
>> }
>>
>> +static const struct spi_nor_otp_ops winbond_otp_ops = {
>> + .read = spi_nor_otp_read_secr,
>> + .write = spi_nor_otp_write_secr,
>> + .lock = spi_nor_otp_lock_sr2,
>> + .is_locked = spi_nor_otp_is_locked_sr2,
>> +};
>
> Should we have this in otp.c? It can be shared with gigadevice as well
> as far as I understood.
It should work in principle for both vendors, but I couldn't test it. So
for now, I've kept it private to winbond.c. If there will be OTP support
for other flashes with the same ops, it should be moved.
-michael
On 3/15/21 11:26 AM, Michael Walle wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> Am 2021-03-15 09:26, schrieb [email protected]:
>> On 3/6/21 2:05 AM, Michael Walle wrote:
>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know
>>> the content is safe
>>>
>>> With all the helper functions in place, add OTP support for the
>>> Winbond
>>> W25Q32JW and W25Q32FW.
>>>
>>> Both were tested on a LS1028A SoC with a NXP FSPI controller.
>>>
>>> Signed-off-by: Michael Walle <[email protected]>
>>> ---
>>> drivers/mtd/spi-nor/winbond.c | 17 +++++++++++++++--
>>> 1 file changed, 15 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/mtd/spi-nor/winbond.c
>>> b/drivers/mtd/spi-nor/winbond.c
>>> index e5dfa786f190..9a3f8ff007fd 100644
>>> --- a/drivers/mtd/spi-nor/winbond.c
>>> +++ b/drivers/mtd/spi-nor/winbond.c
>>> @@ -55,14 +55,18 @@ static const struct flash_info winbond_parts[] = {
>>> { "w25q32", INFO(0xef4016, 0, 64 * 1024, 64, SECT_4K) },
>>> { "w25q32dw", INFO(0xef6016, 0, 64 * 1024, 64,
>>> SECT_4K | SPI_NOR_DUAL_READ |
>>> SPI_NOR_QUAD_READ |
>>> - SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB) },
>>> + SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
>>> + OTP_INFO(256, 3, 0x1000, 0x1000)
>>> + },
>>> +
>>> { "w25q32jv", INFO(0xef7016, 0, 64 * 1024, 64,
>>> SECT_4K | SPI_NOR_DUAL_READ |
>>> SPI_NOR_QUAD_READ |
>>> SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
>>> },
>>> { "w25q32jwm", INFO(0xef8016, 0, 64 * 1024, 64,
>>> SECT_4K | SPI_NOR_DUAL_READ |
>>> SPI_NOR_QUAD_READ |
>>> - SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB) },
>>> + SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
>>> + OTP_INFO(256, 3, 0x1000, 0x1000) },
>>> { "w25q64jwm", INFO(0xef8017, 0, 64 * 1024, 128,
>>> SECT_4K | SPI_NOR_DUAL_READ |
>>> SPI_NOR_QUAD_READ |
>>> SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB) },
>>> @@ -131,9 +135,18 @@ static int winbond_set_4byte_addr_mode(struct
>>> spi_nor *nor, bool enable)
>>> return spi_nor_write_disable(nor);
>>> }
>>>
>>> +static const struct spi_nor_otp_ops winbond_otp_ops = {
>>> + .read = spi_nor_otp_read_secr,
>>> + .write = spi_nor_otp_write_secr,
>>> + .lock = spi_nor_otp_lock_sr2,
>>> + .is_locked = spi_nor_otp_is_locked_sr2,
>>> +};
>>
>> Should we have this in otp.c? It can be shared with gigadevice as well
>> as far as I understood.
>
> It should work in principle for both vendors, but I couldn't test it. So
> for now, I've kept it private to winbond.c. If there will be OTP support
> for other flashes with the same ops, it should be moved.
>
Ok.
On 3/15/21 11:23 AM, Michael Walle wrote:
cut
>>> diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c
>>> new file mode 100644
>>> index 000000000000..4e301fd5156b
>>> --- /dev/null
>>> +++ b/drivers/mtd/spi-nor/otp.c
>>> @@ -0,0 +1,218 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/*
>>> + * OTP support for SPI NOR flashes
>>> + *
>>> + * Copyright (C) 2021 Michael Walle <[email protected]>> + */
>>> +
>>> +#include <linux/log2.h>
>>> +#include <linux/mtd/mtd.h>
>>> +#include <linux/mtd/spi-nor.h>
>>> +
>>> +#include "core.h"
>>> +
>>> +#define spi_nor_otp_ops(nor) ((nor)->params->otp.ops)
>>> +#define spi_nor_otp_region_len(nor) ((nor)->params->otp.org->len)
>>> +#define spi_nor_otp_n_regions(nor)
>>> ((nor)->params->otp.org->n_regions)
>>
>> I don't like these wrappers because they gratuiously hide what's really
>> there.
>> I find the code more easier to read without these wrappers, because I
>> don't
>> have to memorize what these wrappers are doing, and I better see how
>> the code
>> is organized.
>
> TBH I find it easier on the eye and I've never seen so much dereferences
> as in mtd/spi-nor.
It's what I prefer, but it's not a hard requirement. Would you please check
for a second opinion with Vignesh? Inquire about the helpers too. Then do as
you find best.
Cheers,
ta
On 3/15/21 11:39 AM, Tudor Ambarus - M18064 wrote:
> On 3/15/21 11:23 AM, Michael Walle wrote:
>
> cut
>
>>>> diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c
>>>> new file mode 100644
>>>> index 000000000000..4e301fd5156b
>>>> --- /dev/null
>>>> +++ b/drivers/mtd/spi-nor/otp.c
>>>> @@ -0,0 +1,218 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +/*
>>>> + * OTP support for SPI NOR flashes
>>>> + *
>>>> + * Copyright (C) 2021 Michael Walle <[email protected]>> + */
>>>> +
>>>> +#include <linux/log2.h>
>>>> +#include <linux/mtd/mtd.h>
>>>> +#include <linux/mtd/spi-nor.h>
>>>> +
>>>> +#include "core.h"
>>>> +
>>>> +#define spi_nor_otp_ops(nor) ((nor)->params->otp.ops)
>>>> +#define spi_nor_otp_region_len(nor) ((nor)->params->otp.org->len)
>>>> +#define spi_nor_otp_n_regions(nor)
>>>> ((nor)->params->otp.org->n_regions)
>>>
>>> I don't like these wrappers because they gratuiously hide what's really
>>> there.
>>> I find the code more easier to read without these wrappers, because I
>>> don't
>>> have to memorize what these wrappers are doing, and I better see how
>>> the code
>>> is organized.
>>
>> TBH I find it easier on the eye and I've never seen so much dereferences
>> as in mtd/spi-nor.
the dereferences will still be there, but will be just hidden by these wrappers,
don't they? Why would one prefer the wrappers?
>
> It's what I prefer, but it's not a hard requirement. Would you please check
> for a second opinion with Vignesh? Inquire about the helpers too. Then do as
> you find best.
>
> Cheers,
> ta
>
Am 2021-03-15 10:44, schrieb [email protected]:
> On 3/15/21 11:39 AM, Tudor Ambarus - M18064 wrote:
>> On 3/15/21 11:23 AM, Michael Walle wrote:
>>
>> cut
>>
>>>>> diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c
>>>>> new file mode 100644
>>>>> index 000000000000..4e301fd5156b
>>>>> --- /dev/null
>>>>> +++ b/drivers/mtd/spi-nor/otp.c
>>>>> @@ -0,0 +1,218 @@
>>>>> +// SPDX-License-Identifier: GPL-2.0
>>>>> +/*
>>>>> + * OTP support for SPI NOR flashes
>>>>> + *
>>>>> + * Copyright (C) 2021 Michael Walle <[email protected]>> + */
>>>>> +
>>>>> +#include <linux/log2.h>
>>>>> +#include <linux/mtd/mtd.h>
>>>>> +#include <linux/mtd/spi-nor.h>
>>>>> +
>>>>> +#include "core.h"
>>>>> +
>>>>> +#define spi_nor_otp_ops(nor) ((nor)->params->otp.ops)
>>>>> +#define spi_nor_otp_region_len(nor) ((nor)->params->otp.org->len)
>>>>> +#define spi_nor_otp_n_regions(nor)
>>>>> ((nor)->params->otp.org->n_regions)
>>>>
>>>> I don't like these wrappers because they gratuiously hide what's
>>>> really
>>>> there.
>>>> I find the code more easier to read without these wrappers, because
>>>> I
>>>> don't
>>>> have to memorize what these wrappers are doing, and I better see how
>>>> the code
>>>> is organized.
>>>
>>> TBH I find it easier on the eye and I've never seen so much
>>> dereferences
>>> as in mtd/spi-nor.
>
> the dereferences will still be there, but will be just hidden by these
> wrappers,
> don't they? Why would one prefer the wrappers?
That's why I wrote "easier on the eye", yes that is subjective. But
there are also technical aspects, for example, the helpers all
operate on "struct nor*", so you don't have to use the
dereference chain or build up local variables. For example, see
spi_nor_otp_read_write(), it doesn't have to know
anything about the "struct spi_nor_otp_organization".
And of course you could change the actual implementation
without touching the code everywhere,.
-michael