1. 02 6月, 2016 7 次提交
  2. 11 5月, 2016 1 次提交
  3. 08 3月, 2016 11 次提交
  4. 05 3月, 2016 1 次提交
  5. 13 2月, 2016 2 次提交
    • C
      mtd: spi-nor: remove micron_quad_enable() · 3b5394a3
      Cyrille Pitchen 提交于
      This patch remove the micron_quad_enable() function which force the Quad
      SPI mode. However, once this mode is enabled, the Micron memory expect ALL
      commands to use the SPI 4-4-4 protocol. Hence a failure does occur when
      calling spi_nor_wait_till_ready() right after the update of the Enhanced
      Volatile Configuration Register (EVCR) in the micron_quad_enable() as
      the SPI controller driver is not aware about the protocol change.
      
      Since there is almost no performance increase using Fast Read 4-4-4
      commands instead of Fast Read 1-1-4 commands, we rather keep on using the
      Extended SPI mode than enabling the Quad SPI mode.
      
      Let's take the example of the pretty standard use of 8 dummy cycles during
      Fast Read operations on 64KB erase sectors:
      
      Fast Read 1-1-4 requires 8 cycles for the command, then 24 cycles for the
      3byte address followed by 8 dummy clock cycles and finally 65536*2 cycles
      for the read data; so 131112 clock cycles.
      
      On the other hand the Fast Read 4-4-4 would require 2 cycles for the
      command, then 6 cycles for the 3byte address followed by 8 dummy clock
      cycles and finally 65536*2 cycles for the read data. So 131088 clock
      cycles. The theorical bandwidth increase is 0.0%.
      
      Now using Fast Read operations on 512byte pages:
      Fast Read 1-1-4 needs 8+24+8+(512*2) = 1064 clock cycles whereas Fast
      Read 4-4-4 would requires 2+6+8+(512*2) = 1040 clock cycles. Hence the
      theorical bandwidth increase is 2.3%.
      Consecutive reads for non sequential pages is not a relevant use case so
      The Quad SPI mode is not worth it.
      
      mtd_speedtest seems to confirm these figures.
      Signed-off-by: NCyrille Pitchen <cyrille.pitchen@atmel.com>
      Fixes: 548cd3ab ("mtd: spi-nor: Add quad I/O support for Micron SPI NOR")
      Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
      3b5394a3
    • S
      mtd: spi-nor: Add support for s25fl116k · c0826679
      Sascha Hauer 提交于
      The Spansion s25fl116k is a 16MBit NOR Flash supporting dual and
      quad read operations.
      Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
      Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
      c0826679
  6. 27 1月, 2016 1 次提交
  7. 16 1月, 2016 1 次提交
  8. 07 1月, 2016 1 次提交
  9. 06 1月, 2016 2 次提交
  10. 19 12月, 2015 1 次提交
  11. 10 12月, 2015 1 次提交
  12. 05 12月, 2015 2 次提交
  13. 02 12月, 2015 1 次提交
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  15. 20 11月, 2015 2 次提交
  16. 19 11月, 2015 1 次提交
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  18. 12 11月, 2015 3 次提交