| Message ID | 20210120131914.277363-2-tudor.ambarus@microchip.com |
|---|---|
| State | Superseded |
| Delegated to: | Ambarus Tudor |
| Headers | show |
| Series | [v2,1/2] mtd: spi-nor: Add Global Block Unlock command | expand |
Am 2021-01-20 14:19, schrieb Tudor Ambarus: > Even if sst26vf shares the SPINOR_OP_GBULK opcode with > Macronix (ex. MX25U12835F) and Winbound (ex. W25Q128FV), > it has its own Individual Block Protection scheme, which > is also capable to read-lock individual parameter blocks. > Thus the sst26vf's Individual Block Protection scheme will > reside in the sst.c manufacturer driver. > > Add support to unlock the entire flash memory. The device > is write-protected by default after a power-on reset cycle > (volatile software protection), in order to avoid inadvertent > writes during power-up. Could do an erase, write, read back, > and compare when MTD_SPI_NOR_SWP_DISABLE_ON_VOLATILE=y. > > Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> > --- Damn, who on earth assigned the "block protection" bits to the 8/32/64kb sectors on the flash (SST26VF064B DS, Table 5-6). That is nuts. Except one comment below: Reviewed-by: Michael Walle <michael@walle.cc> > v2: s/!ofs/ofs == 0/ > > drivers/mtd/spi-nor/sst.c | 38 ++++++++++++++++++++++++++++++++++++-- > 1 file changed, 36 insertions(+), 2 deletions(-) > > diff --git a/drivers/mtd/spi-nor/sst.c b/drivers/mtd/spi-nor/sst.c > index 00e48da0744a..d6e1396abb96 100644 > --- a/drivers/mtd/spi-nor/sst.c > +++ b/drivers/mtd/spi-nor/sst.c > @@ -8,6 +8,39 @@ > > #include "core.h" > > +static int sst26vf_lock(struct spi_nor *nor, loff_t ofs, uint64_t len) > +{ > + return -EOPNOTSUPP; > +} > + > +static int sst26vf_unlock(struct spi_nor *nor, loff_t ofs, uint64_t > len) > +{ > + if (ofs == 0 && len == nor->params->size) > + return spi_nor_global_block_unlock(nor); Some blocks might not be unlocked because they are permanently locked. Does it make sense to read BPNV of the control register and add a debug message here? -michael > + > + return -EOPNOTSUPP; > +} > + > +static int sst26vf_is_locked(struct spi_nor *nor, loff_t ofs, uint64_t > len) > +{ > + return -EOPNOTSUPP; > +} > + > +static const struct spi_nor_locking_ops sst26vf_locking_ops = { > + .lock = sst26vf_lock, > + .unlock = sst26vf_unlock, > + .is_locked = sst26vf_is_locked, > +}; > + > +static void sst26vf_default_init(struct spi_nor *nor) > +{ > + nor->params->locking_ops = &sst26vf_locking_ops; > +} > + > +static const struct spi_nor_fixups sst26vf_fixups = { > + .default_init = sst26vf_default_init, > +}; > + > static const struct flash_info sst_parts[] = { > /* SST -- large erase sizes are "overlays", "sectors" are 4K */ > { "sst25vf040b", INFO(0xbf258d, 0, 64 * 1024, 8, > @@ -39,8 +72,9 @@ static const struct flash_info sst_parts[] = { > { "sst26vf016b", INFO(0xbf2641, 0, 64 * 1024, 32, > SECT_4K | SPI_NOR_DUAL_READ) }, > { "sst26vf064b", INFO(0xbf2643, 0, 64 * 1024, 128, > - SECT_4K | SPI_NOR_DUAL_READ | > - SPI_NOR_QUAD_READ) }, > + SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | > + SPI_NOR_HAS_LOCK | SPI_NOR_SWP_IS_VOLATILE) > + .fixups = &sst26vf_fixups }, > }; > > static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,
On 1/20/21 4:05 PM, Michael Walle wrote: >> diff --git a/drivers/mtd/spi-nor/sst.c b/drivers/mtd/spi-nor/sst.c >> index 00e48da0744a..d6e1396abb96 100644 >> --- a/drivers/mtd/spi-nor/sst.c >> +++ b/drivers/mtd/spi-nor/sst.c >> @@ -8,6 +8,39 @@ >> >> #include "core.h" >> >> +static int sst26vf_lock(struct spi_nor *nor, loff_t ofs, uint64_t len) >> +{ >> + return -EOPNOTSUPP; >> +} >> + >> +static int sst26vf_unlock(struct spi_nor *nor, loff_t ofs, uint64_t >> len) >> +{ >> + if (ofs == 0 && len == nor->params->size) >> + return spi_nor_global_block_unlock(nor); > > > Some blocks might not be unlocked because they are permanently > locked. Does it make sense to read BPNV of the control register > and add a debug message here? It would, yes. If any block is permanently locked in the unlock_all case, I'll just print a dbg message and return -EINVAL. Sounds good? Cheers, ta
Am 2021-01-20 15:52, schrieb Tudor.Ambarus@microchip.com: > On 1/20/21 4:05 PM, Michael Walle wrote: >>> diff --git a/drivers/mtd/spi-nor/sst.c b/drivers/mtd/spi-nor/sst.c >>> index 00e48da0744a..d6e1396abb96 100644 >>> --- a/drivers/mtd/spi-nor/sst.c >>> +++ b/drivers/mtd/spi-nor/sst.c >>> @@ -8,6 +8,39 @@ >>> >>> #include "core.h" >>> >>> +static int sst26vf_lock(struct spi_nor *nor, loff_t ofs, uint64_t >>> len) >>> +{ >>> + return -EOPNOTSUPP; >>> +} >>> + >>> +static int sst26vf_unlock(struct spi_nor *nor, loff_t ofs, uint64_t >>> len) >>> +{ >>> + if (ofs == 0 && len == nor->params->size) >>> + return spi_nor_global_block_unlock(nor); >> >> >> Some blocks might not be unlocked because they are permanently >> locked. Does it make sense to read BPNV of the control register >> and add a debug message here? > > It would, yes. If any block is permanently locked in the unlock_all > case, > I'll just print a dbg message and return -EINVAL. Sounds good? spi_nor_sr_unlock(), atmel_at25fs_unlock() and atmel_global_unprotect() will return -EIO in case the SR wasn't writable. -michael
On 1/20/21 5:02 PM, Michael Walle wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > Am 2021-01-20 15:52, schrieb Tudor.Ambarus@microchip.com: >> On 1/20/21 4:05 PM, Michael Walle wrote: >>>> diff --git a/drivers/mtd/spi-nor/sst.c b/drivers/mtd/spi-nor/sst.c >>>> index 00e48da0744a..d6e1396abb96 100644 >>>> --- a/drivers/mtd/spi-nor/sst.c >>>> +++ b/drivers/mtd/spi-nor/sst.c >>>> @@ -8,6 +8,39 @@ >>>> >>>> #include "core.h" >>>> >>>> +static int sst26vf_lock(struct spi_nor *nor, loff_t ofs, uint64_t >>>> len) >>>> +{ >>>> + return -EOPNOTSUPP; >>>> +} >>>> + >>>> +static int sst26vf_unlock(struct spi_nor *nor, loff_t ofs, uint64_t >>>> len) >>>> +{ >>>> + if (ofs == 0 && len == nor->params->size) >>>> + return spi_nor_global_block_unlock(nor); >>> >>> >>> Some blocks might not be unlocked because they are permanently >>> locked. Does it make sense to read BPNV of the control register >>> and add a debug message here? >> >> It would, yes. If any block is permanently locked in the unlock_all >> case, >> I'll just print a dbg message and return -EINVAL. Sounds good? > > spi_nor_sr_unlock(), atmel_at25fs_unlock() and atmel_global_unprotect() > will return -EIO in case the SR wasn't writable. You mean in the spi_nor_write_sr_and_check() calls. -EIO is fine there if what we wrote is different than what we read back, it would indicate an IO error. GBULK command clears all the write-protection bits in the Block Protection register, except for those bits that have been permanently locked down. So even if we have few blocks permanently locked, i.e. CR.BPNV == 1, the GBULK can clear the protection for the remaining blocks. So not really an IO error, but rather an -EINVAL, because the user asks to unlock more than we can. Cheers, ta
Am 2021-01-20 16:39, schrieb Tudor.Ambarus@microchip.com: > On 1/20/21 5:02 PM, Michael Walle wrote: >> EXTERNAL EMAIL: Do not click links or open attachments unless you know >> the content is safe >> >> Am 2021-01-20 15:52, schrieb Tudor.Ambarus@microchip.com: >>> On 1/20/21 4:05 PM, Michael Walle wrote: >>>>> diff --git a/drivers/mtd/spi-nor/sst.c b/drivers/mtd/spi-nor/sst.c >>>>> index 00e48da0744a..d6e1396abb96 100644 >>>>> --- a/drivers/mtd/spi-nor/sst.c >>>>> +++ b/drivers/mtd/spi-nor/sst.c >>>>> @@ -8,6 +8,39 @@ >>>>> >>>>> #include "core.h" >>>>> >>>>> +static int sst26vf_lock(struct spi_nor *nor, loff_t ofs, uint64_t >>>>> len) >>>>> +{ >>>>> + return -EOPNOTSUPP; >>>>> +} >>>>> + >>>>> +static int sst26vf_unlock(struct spi_nor *nor, loff_t ofs, >>>>> uint64_t >>>>> len) >>>>> +{ >>>>> + if (ofs == 0 && len == nor->params->size) >>>>> + return spi_nor_global_block_unlock(nor); >>>> >>>> >>>> Some blocks might not be unlocked because they are permanently >>>> locked. Does it make sense to read BPNV of the control register >>>> and add a debug message here? >>> >>> It would, yes. If any block is permanently locked in the unlock_all >>> case, >>> I'll just print a dbg message and return -EINVAL. Sounds good? >> >> spi_nor_sr_unlock(), atmel_at25fs_unlock() and >> atmel_global_unprotect() >> will return -EIO in case the SR wasn't writable. > > You mean in the spi_nor_write_sr_and_check() calls. -EIO is fine > there if what we wrote is different than what we read back, it would > indicate an IO error. > > GBULK command clears all the write-protection bits in the Block > Protection register, except for those bits that have been permanently > locked down. So even if we have few blocks permanently locked, i.e. > CR.BPNV == 1, the GBULK can clear the protection for the remaining > blocks. So not really an IO error, but rather an -EINVAL, because > the user asks to unlock more than we can. Doesn't EINVAL indicate wrong parameters, but does nothing? In this case, unlock would be partially successful. In any case, my point was that depending on the underlying locking ops, either -EIO or -EINVAL is returned if spi_nor_unlock() fails for the same reason, that is unlock() wasn't possible because of some sort of hardware write protection. And IMHO it should return the same errno (whatever the correct errno is in this case). -michael
On 1/20/21 5:49 PM, Michael Walle wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > Am 2021-01-20 16:39, schrieb Tudor.Ambarus@microchip.com: >> On 1/20/21 5:02 PM, Michael Walle wrote: >>> EXTERNAL EMAIL: Do not click links or open attachments unless you know >>> the content is safe >>> >>> Am 2021-01-20 15:52, schrieb Tudor.Ambarus@microchip.com: >>>> On 1/20/21 4:05 PM, Michael Walle wrote: >>>>>> diff --git a/drivers/mtd/spi-nor/sst.c b/drivers/mtd/spi-nor/sst.c >>>>>> index 00e48da0744a..d6e1396abb96 100644 >>>>>> --- a/drivers/mtd/spi-nor/sst.c >>>>>> +++ b/drivers/mtd/spi-nor/sst.c >>>>>> @@ -8,6 +8,39 @@ >>>>>> >>>>>> #include "core.h" >>>>>> >>>>>> +static int sst26vf_lock(struct spi_nor *nor, loff_t ofs, uint64_t >>>>>> len) >>>>>> +{ >>>>>> + return -EOPNOTSUPP; >>>>>> +} >>>>>> + >>>>>> +static int sst26vf_unlock(struct spi_nor *nor, loff_t ofs, >>>>>> uint64_t >>>>>> len) >>>>>> +{ >>>>>> + if (ofs == 0 && len == nor->params->size) >>>>>> + return spi_nor_global_block_unlock(nor); >>>>> >>>>> >>>>> Some blocks might not be unlocked because they are permanently >>>>> locked. Does it make sense to read BPNV of the control register >>>>> and add a debug message here? >>>> >>>> It would, yes. If any block is permanently locked in the unlock_all >>>> case, >>>> I'll just print a dbg message and return -EINVAL. Sounds good? >>> >>> spi_nor_sr_unlock(), atmel_at25fs_unlock() and >>> atmel_global_unprotect() >>> will return -EIO in case the SR wasn't writable. >> >> You mean in the spi_nor_write_sr_and_check() calls. -EIO is fine >> there if what we wrote is different than what we read back, it would >> indicate an IO error. >> >> GBULK command clears all the write-protection bits in the Block >> Protection register, except for those bits that have been permanently >> locked down. So even if we have few blocks permanently locked, i.e. >> CR.BPNV == 1, the GBULK can clear the protection for the remaining >> blocks. So not really an IO error, but rather an -EINVAL, because >> the user asks to unlock more than we can. > > Doesn't EINVAL indicate wrong parameters, but does nothing? In this > case, unlock would be partially successful. > yes, that's what I said I'll do: "If any block is permanently locked in the unlock_all case, I'll just print a dbg message and return -EINVAL", without sending a GBULK cmd. Caller wrongly asks to unlock all, when we can just unlock partial memory. It's similar to what is at: https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git/tree/drivers/mtd/spi-nor/core.c?h=spi-nor/next#n1946 > In any case, my point was that depending on the underlying locking > ops, either -EIO or -EINVAL is returned if spi_nor_unlock() fails > for the same reason, that is unlock() wasn't possible because of > some sort of hardware write protection. And IMHO it should return > the same errno (whatever the correct errno is in this case). > But the reasons are different: 1/caller wrongly asks to unlock more than we can, thus -EINVAL 2/ -EIO when we don't read what we expect to read. Cheers, ta
Am 2021-01-20 17:25, schrieb Tudor.Ambarus@microchip.com: > On 1/20/21 5:49 PM, Michael Walle wrote: >> EXTERNAL EMAIL: Do not click links or open attachments unless you know >> the content is safe >> >> Am 2021-01-20 16:39, schrieb Tudor.Ambarus@microchip.com: >>> On 1/20/21 5:02 PM, Michael Walle wrote: >>>> EXTERNAL EMAIL: Do not click links or open attachments unless you >>>> know >>>> the content is safe >>>> >>>> Am 2021-01-20 15:52, schrieb Tudor.Ambarus@microchip.com: >>>>> On 1/20/21 4:05 PM, Michael Walle wrote: >>>>>>> diff --git a/drivers/mtd/spi-nor/sst.c >>>>>>> b/drivers/mtd/spi-nor/sst.c >>>>>>> index 00e48da0744a..d6e1396abb96 100644 >>>>>>> --- a/drivers/mtd/spi-nor/sst.c >>>>>>> +++ b/drivers/mtd/spi-nor/sst.c >>>>>>> @@ -8,6 +8,39 @@ >>>>>>> >>>>>>> #include "core.h" >>>>>>> >>>>>>> +static int sst26vf_lock(struct spi_nor *nor, loff_t ofs, >>>>>>> uint64_t >>>>>>> len) >>>>>>> +{ >>>>>>> + return -EOPNOTSUPP; >>>>>>> +} >>>>>>> + >>>>>>> +static int sst26vf_unlock(struct spi_nor *nor, loff_t ofs, >>>>>>> uint64_t >>>>>>> len) >>>>>>> +{ >>>>>>> + if (ofs == 0 && len == nor->params->size) >>>>>>> + return spi_nor_global_block_unlock(nor); >>>>>> >>>>>> >>>>>> Some blocks might not be unlocked because they are permanently >>>>>> locked. Does it make sense to read BPNV of the control register >>>>>> and add a debug message here? >>>>> >>>>> It would, yes. If any block is permanently locked in the unlock_all >>>>> case, >>>>> I'll just print a dbg message and return -EINVAL. Sounds good? >>>> >>>> spi_nor_sr_unlock(), atmel_at25fs_unlock() and >>>> atmel_global_unprotect() >>>> will return -EIO in case the SR wasn't writable. >>> >>> You mean in the spi_nor_write_sr_and_check() calls. -EIO is fine >>> there if what we wrote is different than what we read back, it would >>> indicate an IO error. >>> >>> GBULK command clears all the write-protection bits in the Block >>> Protection register, except for those bits that have been permanently >>> locked down. So even if we have few blocks permanently locked, i.e. >>> CR.BPNV == 1, the GBULK can clear the protection for the remaining >>> blocks. So not really an IO error, but rather an -EINVAL, because >>> the user asks to unlock more than we can. >> >> Doesn't EINVAL indicate wrong parameters, but does nothing? In this >> case, unlock would be partially successful. >> > yes, that's what I said I'll do: "If any block is permanently locked > in the unlock_all case, I'll just print a dbg message and return > -EINVAL", > without sending a GBULK cmd. Caller wrongly asks to unlock all, when we > can just unlock partial memory. Doh, I've missed that you will do it beforehand. Yes then EINVAL is fine by me. But you won't unlock the flash during startup (given the config option is enabled) if any blocks has been permanently locked. Thus if just the topmost 4k block is permanently locked down, the whole flash wouldn't be writable, right?. I don't have a strong opinion on that. -michael > > It's similar to what is at: > https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git/tree/drivers/mtd/spi-nor/core.c?h=spi-nor/next#n1946 > >> In any case, my point was that depending on the underlying locking >> ops, either -EIO or -EINVAL is returned if spi_nor_unlock() fails >> for the same reason, that is unlock() wasn't possible because of >> some sort of hardware write protection. And IMHO it should return >> the same errno (whatever the correct errno is in this case). >> > > But the reasons are different: 1/caller wrongly asks to unlock > more than we can, thus -EINVAL 2/ -EIO when we don't read what > we expect to read. -michael
On 1/20/21 6:47 PM, Michael Walle wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > Am 2021-01-20 17:25, schrieb Tudor.Ambarus@microchip.com: >> On 1/20/21 5:49 PM, Michael Walle wrote: >>> EXTERNAL EMAIL: Do not click links or open attachments unless you know >>> the content is safe >>> >>> Am 2021-01-20 16:39, schrieb Tudor.Ambarus@microchip.com: >>>> On 1/20/21 5:02 PM, Michael Walle wrote: >>>>> EXTERNAL EMAIL: Do not click links or open attachments unless you >>>>> know >>>>> the content is safe >>>>> >>>>> Am 2021-01-20 15:52, schrieb Tudor.Ambarus@microchip.com: >>>>>> On 1/20/21 4:05 PM, Michael Walle wrote: >>>>>>>> diff --git a/drivers/mtd/spi-nor/sst.c >>>>>>>> b/drivers/mtd/spi-nor/sst.c >>>>>>>> index 00e48da0744a..d6e1396abb96 100644 >>>>>>>> --- a/drivers/mtd/spi-nor/sst.c >>>>>>>> +++ b/drivers/mtd/spi-nor/sst.c >>>>>>>> @@ -8,6 +8,39 @@ >>>>>>>> >>>>>>>> #include "core.h" >>>>>>>> >>>>>>>> +static int sst26vf_lock(struct spi_nor *nor, loff_t ofs, >>>>>>>> uint64_t >>>>>>>> len) >>>>>>>> +{ >>>>>>>> + return -EOPNOTSUPP; >>>>>>>> +} >>>>>>>> + >>>>>>>> +static int sst26vf_unlock(struct spi_nor *nor, loff_t ofs, >>>>>>>> uint64_t >>>>>>>> len) >>>>>>>> +{ >>>>>>>> + if (ofs == 0 && len == nor->params->size) >>>>>>>> + return spi_nor_global_block_unlock(nor); >>>>>>> >>>>>>> >>>>>>> Some blocks might not be unlocked because they are permanently >>>>>>> locked. Does it make sense to read BPNV of the control register >>>>>>> and add a debug message here? >>>>>> >>>>>> It would, yes. If any block is permanently locked in the unlock_all >>>>>> case, >>>>>> I'll just print a dbg message and return -EINVAL. Sounds good? >>>>> >>>>> spi_nor_sr_unlock(), atmel_at25fs_unlock() and >>>>> atmel_global_unprotect() >>>>> will return -EIO in case the SR wasn't writable. >>>> >>>> You mean in the spi_nor_write_sr_and_check() calls. -EIO is fine >>>> there if what we wrote is different than what we read back, it would >>>> indicate an IO error. >>>> >>>> GBULK command clears all the write-protection bits in the Block >>>> Protection register, except for those bits that have been permanently >>>> locked down. So even if we have few blocks permanently locked, i.e. >>>> CR.BPNV == 1, the GBULK can clear the protection for the remaining >>>> blocks. So not really an IO error, but rather an -EINVAL, because >>>> the user asks to unlock more than we can. >>> >>> Doesn't EINVAL indicate wrong parameters, but does nothing? In this >>> case, unlock would be partially successful. >>> >> yes, that's what I said I'll do: "If any block is permanently locked >> in the unlock_all case, I'll just print a dbg message and return >> -EINVAL", >> without sending a GBULK cmd. Caller wrongly asks to unlock all, when we >> can just unlock partial memory. > > Doh, I've missed that you will do it beforehand. Yes then EINVAL > is fine by me. > > But you won't unlock the flash during startup (given the config option > is enabled) if any blocks has been permanently locked. Thus if just the > topmost 4k block is permanently locked down, the whole flash wouldn't be > writable, right?. I don't have a strong opinion on that. Correct. I don't see problems with that. Individual Block protection with unlock on a smaller granularity can be added later on, and the behavior during boot will remain the same. Cheers, ta
diff --git a/drivers/mtd/spi-nor/sst.c b/drivers/mtd/spi-nor/sst.c index 00e48da0744a..d6e1396abb96 100644 --- a/drivers/mtd/spi-nor/sst.c +++ b/drivers/mtd/spi-nor/sst.c @@ -8,6 +8,39 @@ #include "core.h" +static int sst26vf_lock(struct spi_nor *nor, loff_t ofs, uint64_t len) +{ + return -EOPNOTSUPP; +} + +static int sst26vf_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len) +{ + if (ofs == 0 && len == nor->params->size) + return spi_nor_global_block_unlock(nor); + + return -EOPNOTSUPP; +} + +static int sst26vf_is_locked(struct spi_nor *nor, loff_t ofs, uint64_t len) +{ + return -EOPNOTSUPP; +} + +static const struct spi_nor_locking_ops sst26vf_locking_ops = { + .lock = sst26vf_lock, + .unlock = sst26vf_unlock, + .is_locked = sst26vf_is_locked, +}; + +static void sst26vf_default_init(struct spi_nor *nor) +{ + nor->params->locking_ops = &sst26vf_locking_ops; +} + +static const struct spi_nor_fixups sst26vf_fixups = { + .default_init = sst26vf_default_init, +}; + static const struct flash_info sst_parts[] = { /* SST -- large erase sizes are "overlays", "sectors" are 4K */ { "sst25vf040b", INFO(0xbf258d, 0, 64 * 1024, 8, @@ -39,8 +72,9 @@ static const struct flash_info sst_parts[] = { { "sst26vf016b", INFO(0xbf2641, 0, 64 * 1024, 32, SECT_4K | SPI_NOR_DUAL_READ) }, { "sst26vf064b", INFO(0xbf2643, 0, 64 * 1024, 128, - SECT_4K | SPI_NOR_DUAL_READ | - SPI_NOR_QUAD_READ) }, + SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | + SPI_NOR_HAS_LOCK | SPI_NOR_SWP_IS_VOLATILE) + .fixups = &sst26vf_fixups }, }; static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,
Even if sst26vf shares the SPINOR_OP_GBULK opcode with Macronix (ex. MX25U12835F) and Winbound (ex. W25Q128FV), it has its own Individual Block Protection scheme, which is also capable to read-lock individual parameter blocks. Thus the sst26vf's Individual Block Protection scheme will reside in the sst.c manufacturer driver. Add support to unlock the entire flash memory. The device is write-protected by default after a power-on reset cycle (volatile software protection), in order to avoid inadvertent writes during power-up. Could do an erase, write, read back, and compare when MTD_SPI_NOR_SWP_DISABLE_ON_VOLATILE=y. Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> --- v2: s/!ofs/ofs == 0/ drivers/mtd/spi-nor/sst.c | 38 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 36 insertions(+), 2 deletions(-)