[PATCH v4 00/20] mtd: spi-nor: Quad Enable and (un)lock methods

Tudor.Ambarus at microchip.com Tudor.Ambarus at microchip.com
Sat Nov 2 04:23:23 PDT 2019

From: Tudor Ambarus <tudor.ambarus at microchip.com>

Tested on s25fl116k and w25q128jv-q.

Fixed the clearing of QE bit on (un)lock() operations. Reworked the
Quad Enable methods and the disabling of the block write protection
at power-up.

- Use dev_dbg insted of dev_err for low level info
- replace "&nor->bouncebuf[0]" with "nor->bouncebuf" and "&sr_cr[0]" with
  "sr_cr". Update across all patches.

v3: split patches, update retlen handling in sst_write.

- Introduce spi_nor_write_16bit_cr_and_check() as per Vignesh's suggestion. The
  Configuration Register contains bits that can be updated in future: FREEZE,
  CMP. Provide a generic method that allows updating all bits of the
  Configuration Register.
- Fix SNOR_F_NO_READ_CR case in
  "mtd: spi-nor: Rework the disabling of block write protection". When the flash
  doesn't support the CR Read command, we make an assumption about the value of
  the QE bit. In spi_nor_init(), call spi_nor_quad_enable() first, then
  spi_nor_unlock_all(), so that at the spi_nor_unlock_all() time we can be sure
  the QE bit has value one, because of the previous call to spi_nor_quad_enable().
- Fix if statement in spi_nor_write_sr_and_check():
  if (nor->flags & SNOR_F_HAS_16BIT_SR)
- Fix documentation warnings.
- New patch: "mtd: spi-nor: Check all the bits written, not just the BP ones".
- Drop Global Unlock patches, will send them in a different patch set.

The patch set can be tested using mtd-utils:
1/ do a read-erase-write-read-back test immediately after boot, to check
the spi_nor_unlock_all() method. The focus is on the erase/write
methods, we want to see if the flash is unlocked at power-up.
        mtd_debug read /dev/mtd-yours offset size read-file
        hexdump read-file
        mtd_debug erase /dev/mtd-yours offset size
        dd if=/dev/urandom of=write-file bs=please-choose count=please-choose
        mtd_debug write /dev/mtd-yours offset write-file-size write-file
        mtd_debug read /dev/mtd-yours offset write-file-size read-file
        sha1sum read-file write-file
2/ lock flash then try to erase/write it, to see if the lock works
        flash_lock /dev/mtd-yours offset block-count
        Do the read-erase-write-read-back test from 1/. The contents of
        flash should not change in the erase and write steps.
3/ unlock flash and do the read-erase-write-read-back from 1/. The value of the
   QEE should not change and you should be able to erase and write the flash.
   Test 1/ should be successful.

Tudor Ambarus (20):
  mtd: spi-nor: Use dev_dbg insted of dev_err for low level info
  mtd: spi-nor: Print debug info inside Reg Ops methods
  mtd: spi-nor: Check for errors after each Register Operation
  mtd: spi-nor: Rename label as it is no longer generic
  mtd: spi-nor: Void return type for spi_nor_clear_sr/fsr()
  mtd: spi-nor: Move the WE and wait calls inside Write SR methods
  mtd: spi-nor: Merge spi_nor_write_sr() and spi_nor_write_sr_cr()
  mtd: spi-nor: Describe all the Reg Ops
  mtd: spi-nor: Drop spansion_quad_enable()
  mtd: spi-nor: Fix errno on Quad Enable methods
  mtd: spi-nor: Check all the bits written, not just the BP ones
  mtd: spi-nor: Print debug message when the read back test fails
  mtd: spi-nor: Fix clearing of QE bit on lock()/unlock()
  mtd: spi-nor: Extend the QE Read Back test to the entire SR byte
  mtd: spi-nor: Extend the QE Read Back test to both SR1 and SR2
  mtd: spi-nor: Rename CR_QUAD_EN_SPAN to SR2_QUAD_EN_BIT1
  mtd: spi-nor: Merge spansion Quad Enable methods
  mtd: spi-nor: Rename macronix_quad_enable to
  mtd: spi-nor: Prepend "spi_nor_" to "sr2_bit7_quad_enable"
  mtd: spi-nor: Rework the disabling of block write protection

 drivers/mtd/spi-nor/spi-nor.c | 952 +++++++++++++++++++++++++-----------------
 include/linux/mtd/spi-nor.h   |  12 +-
 2 files changed, 583 insertions(+), 381 deletions(-)


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