[Bug 1001850] New: Flash Driver for Cypress FM25VXX FRAM

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http://bugs.ecos.sourceware.org/show_bug.cgi?id=1001850

            Bug ID: 1001850
           Summary: Flash Driver for Cypress FM25VXX FRAM
           Product: eCos
           Version: unknown
            Target: freescale_twr_k60n512 (Freescale Kinetis TWR-K60N512)
  Architecture/Host Cortex-M
                OS:
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: low
         Component: Flash
          Assignee: unassigned@bugs.ecos.sourceware.org
          Reporter: mjones@linear.com
                CC: ecos-bugs@ecos.sourceware.org

Created attachment 2239
  --> http://bugs.ecos.sourceware.org/attachment.cgi?id=2239&action=edit
Cypress Flash support for FM25VXX FRAM on Kinetis

This is a working driver for Cypress FM25VXX FRAM for Kinetis K60 FXM.

Several things to note about its current status:

- Supports 256kB, 512KB, 1MB devices (tested with 512KB device)

- FRAM has no blocks, so the flash API is implemented as a single block device.

- Erase is implemented by writing 0xFF. It is not very time efficient, but it
is very memory efficient. If one really wants to erase, it will be much faster
to write 0xFF from your own larger buffer.

- It has a CDL setting to control the write block size if desired.

- It works with SPI polled mode, but does not completely work with SPI DMA
mode. A write followed by a read produces read data that has one 0x00 byte at
the beginning. This seems to be related to the underlying SPI code.

- The test code has been run in other application files and should work, but
the erase will be very slow. You can comment the erase and it should run. The
code is just a tweaked version of SST25 test code.

- Normal READ mode tested. FAST READ mode not tested.

- It has been used with an existing application and is reliable in polled mode
with normal READ mode.

- With the SPI speed set to 25Mhz, the actual frequency is 12.5Mhz. Increasing
SPI setting has no effect.

Issues that need resolving:

- DMA function
- SPI frequency
- Block erase strategy
- More testing

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