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  1. 15 Jan, 2014 1 commit
  3. 14 Jan, 2014 5 commits
    • Brian Norris's avatar
      mtd: nand: use __packed shorthand · e2e6b7b7
      Brian Norris authored 
      To be consistent with the rest of include/linux/mtd/nand.h, we should
use the __packed shorthand instead of __attribute__((packed)).
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
Acked-by: default avatarHuang Shijie <b32955@freescale.com>
      e2e6b7b7
    • Brian Norris's avatar
      mtd: nand: support Micron READ RETRY · 8429bb39
      Brian Norris authored 
      Micron provides READ RETRY support via the ONFI vendor-specific
parameter block (to indicate how many read-retry modes are available)
and the ONFI {GET,SET}_FEATURES commands with a vendor-specific feature
address (to support reading/switching the current read-retry mode).

The recommended sequence is as follows:

  1. Perform PAGE_READ operation
  2. If no ECC error, we are done
  3. Run SET_FEATURES with feature address 89h, mode 1
  4. Retry PAGE_READ operation
  5. If ECC error and there are remaining supported modes, increment the
     mode and return to step 3. Otherwise, this is a true ECC error.
  6. Run SET_FEATURES with feature address 89h, mode 0, to return to the
     default state.

This patch implements the chip->setup_read_retry() callback for
Micron and fills in the chip->read_retries.

Tested on Micron MT29F32G08CBADA, which supports 8 read-retry modes.

The Micron vendor-specific table was checked against the datasheets for
the following Micron NAND:

Needs retry   Cell-type    Part number          Vendor revision    Byte 180
-----------   ---------    ----------------     ---------------    ------------
No            SLC          MT29F16G08ABABA      1                  Reserved (0)
No            MLC          MT29F32G08CBABA      1                  Reserved (0)
No            SLC          MT29F1G08AACWP       1                  0
Yes           MLC          MT29F32G08CBADA      1                  08h
Yes           MLC          MT29F64G08CBABA      2                  08h
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
Acked-by: default avatarHuang Shijie <b32955@freescale.com>
      8429bb39
    • Brian Norris's avatar
      mtd: nand: add generic READ RETRY support · ba84fb59
      Brian Norris authored 
      Modern MLC (and even SLC?) NAND can experience a large number of
bitflips (beyond the recommended correctability capacity) due to drifts
in the voltage threshold (Vt). These bitflips can cause ECC errors to
occur well within the expected lifetime of the flash. To account for
this, some manufacturers provide a mechanism for shifting the Vt
threshold after a corrupted read.

The generic pattern seems to be that a particular flash has N read retry
modes (where N = 0, traditionally), and after an ECC failure, the host
should reconfigure the flash to use the next available mode, then retry
the read operation. This process repeats until all bitfips can be
corrected or until the host has tried all available retry modes.

This patch adds the infrastructure support for a
vendor-specific/flash-specific callback, used for setting the read-retry
mode (i.e., voltage threshold).

For now, this patch always returns the flash to mode 0 (the default
mode) after a successful read-retry, according to the flowchart found in
Micron's datasheets. This may need to change in the future if it is
determined that eventually, mode 0 is insufficient for the majority of
the flash cells (and so for performance reasons, we should leave the
flash in mode 1, 2, etc.).
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
Acked-by: default avatarHuang Shijie <b32955@freescale.com>
      ba84fb59
    • Brian Norris's avatar
      mtd: nand: add ONFI vendor block for Micron · 6f0065b0
      Brian Norris authored 
      Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
Acked-by: default avatarHuang Shijie <b32955@freescale.com>
      6f0065b0
    • Brian Norris's avatar
      mtd: nand: localize ECC failures per page · b72f3dfb
      Brian Norris authored 
      ECC failures can be tracked at the page level, not the do_read_ops level
(i.e., a potentially multi-page transaction).

This helps prepare for READ RETRY support.
Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
Acked-by: default avatarHuang Shijie <b32955@freescale.com>
      b72f3dfb
  5. 13 Jan, 2014 1 commit
  7. 11 Jan, 2014 7 commits
  9. 09 Jan, 2014 1 commit
  11. 07 Jan, 2014 20 commits
  13. 03 Jan, 2014 5 commits
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