Flash interface #2239

d00616 · 2015-01-03T21:13:26Z

Here is my actual work on an interface to flash storage for discussion. I have added a simulation. Persistent storage can be added by give a file name via "-F" command line option.

I have no plan to support EEPROM here. At AVR MCU EEPROM cannot accessed directly via memory access. I haven't found any other MCU with EEPROM. It looks like most actual MCU have only flash storage.

My next step is commit support for nRF51 MCU.

When this finished i plan to implement an persistent configuration storage taking care of limited write cycles of flash memory. I plant to put it into this PR.

LudwigKnuepfer · 2015-01-04T09:03:56Z

I'll open a PR against your branch with the native specific review.

Please split the interface, test, native, and the preliminary nrf additions into separate commits.

LudwigKnuepfer · 2015-01-04T09:13:08Z

tests/periph_flash/main.c

+
+int main(void)
+{
+    // Signature with space for alignment


please use /* comment style */

d00616 · 2015-01-04T19:11:44Z

I plan change flash_get_page_number and flash_get_address to give an return code to add an address check or give back NULL if requested page outside flash area.

@LudwigOrtmann I'll change it after your PR.

missing bits and pieces, spelling, etc

LudwigKnuepfer · 2015-01-04T21:12:40Z

Here's my native review PR: d00616#1

New flash interface review

d00616 · 2015-01-06T14:40:43Z

drivers/include/periph/flash.h

+ * @return    FLASH_ERROR_LOCKED
+ * @return    FLASH_ERROR_TIMEOUT
+ */
+uint8_t flash_memcpy_fast(void *dest, const void *src, size_t n);


I think we can remove this functionality. I have planned it to check alignment in test suite and for additional functionality. But while i implement an NRF51 version for flash i see that unaligned writes are impossible because i must write an word and wait for finishing opation to proceed with the next word.

PeterKietzmann · 2016-03-23T13:53:53Z

Honestly I currently don't have an opinion here and won't find time to care about. Let's postpone for this release

kYc0o · 2016-03-23T13:57:29Z

I would vote for some file system instead of raw writings to the external memories (either flash or EEPROM). There is an effort in #2474 but it seems abandoned...

OlegHahm · 2016-03-23T14:06:39Z

Having an interface to write into flash seems to be a prerequisite for using a filesystem on flash memory.

kYc0o · 2016-03-23T14:13:03Z

IMO we should use directly the low level driver depending on the memory type (I2C, SPI) which would be used by the file system

OlegHahm · 2016-03-23T14:16:45Z

Hm, but using a filesystem might introduce some overhead when an application just wants to store some simple information onto persistent memory. Think of something like a persistent configuration for the radio (e.g. channel, PAN ID etc.).

kYc0o · 2016-03-23T15:12:20Z

Oh yes, that way it can be useful to easily write out of the filesystem memory space. I'll try to review this but as it's tagged for the next release I'll do it after this one :)

LudwigKnuepfer · 2016-03-23T22:50:30Z

A flash abstraction layer is definitely desirable and can not be replaced by a file system.
One example: firmware update.

kYc0o · 2016-03-24T10:16:26Z

Yes I totally agree, but I would see it as a device driver that can be then leveraged by the file system (with simple functions like read/write/erase). Firmware updates can also leverage the FS to easily find the binaries needed for update.

LudwigKnuepfer · 2016-04-01T19:27:52Z

drivers/include/periph/flash.h

+ * @return    FLASH_ERROR_VERIFY
+ * @return    FLASH_ERROR_ADDR_RANGE
+ */
+uint8_t flash_memcpy(void *dest, const void *src, size_t n);


void *dest - the flash size may exceed the native address space.

kYc0o · 2016-07-22T12:16:24Z

Several other options exist now to add this new feature, so I'll postpone this one in order to give a detailed review of all the propositions.

miri64 · 2016-09-27T09:45:36Z

well the question is: do we want to keep this open now that there are some alternatives?

OlegHahm · 2016-10-12T17:46:26Z

Maybe we should start a flash interface task force and consolidate the efforts?

miri64 · 2016-10-31T13:34:29Z

Postponed due to Feature Freeze.

OlegHahm · 2017-01-15T10:20:16Z

@haukepetersen, how does this PR relates to the other efforts in this direction?

haukepetersen · 2017-01-16T09:47:25Z

IMHO, this PR is 80-90% the same thing as the already merged 'periph/flashpage` interface - just by a magnitude more complex.. (e.g. for the nrf5x: 282 lines of code in this PR vs 47 lines for the flashpage driver). The main difference I see is that this PR allows to write parts of pages, or even multiple pages at once, while the existing interface allows only for writing one complete page at a time.

My suggestion would be to do the following:

add something like flashpage_write_raw(void *start, void *data, size_t len) to the existing flashpage interface
port the implementation for native to the flashapge interface

kYc0o · 2017-01-16T11:29:58Z

add something like flashpage_write_raw(void *start, void *data, size_t len) to the existing flashpage interface
port the implementation for native to the flashapge interface

+1 👍

miri64 · 2017-01-24T14:50:40Z

Closed as memo

d00616 added 2 commits January 3, 2015 22:03

Flash interface for native CPU

9eb1c91

fix doxygen error

6a66b55

LudwigKnuepfer self-assigned this Jan 4, 2015

LudwigKnuepfer added Type: new feature The issue requests / The PR implemements a new feature for RIOT Area: drivers Area: Device drivers labels Jan 4, 2015

LudwigKnuepfer reviewed Jan 4, 2015
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tests/periph_flash/main.c

int main(void)

{

// Signature with space for alignment

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please use /* comment style */

d00616 closed this Jan 4, 2015

d00616 reopened this Jan 4, 2015

LudwigKnuepfer added 5 commits January 4, 2015 21:48

general review of native parts

ca618f4

missing bits and pieces, spelling, etc

native/flash: remove duplicated API

0068cb2

cpu/native: use mmap for periph/flash

5e0e305

cpu/native: make flash volatile

08d5847

cpu/native: clean up flash macro definitions

9706d25

d00616 and others added 4 commits January 5, 2015 18:23

Merge pull request #1 from LudwigOrtmann/new_flash_interface-review

bee55cd

New flash interface review

ERASED_BIT_VALUE -> ERASED_WORD_VALUE

6c7c5bb

FLASH_ERASED_WORD_VALUE in tests/periph_flash

0199abc

PR comments (tab stops, comments)

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OlegHahm added the Community: Hack'n'ACK candidate This PR is a candidate for review and discussion during one of RIOT's monthly Hack'n'ACK parties label Jan 6, 2015

d00616 reviewed Jan 6, 2015
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PeterKietzmann modified the milestones: Release 2016.07, Release 2016.04 Mar 23, 2016

LudwigKnuepfer reviewed Apr 1, 2016
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x3ro mentioned this pull request Apr 26, 2016

State of low-level flash storage interfaces #5398

Closed

LudwigKnuepfer mentioned this pull request Jul 12, 2016

mtd flash: add a generic low level flash interface [RFC] #5624

Merged

jnohlgard mentioned this pull request Jul 13, 2016

vfs: file system abstraction #5616

Merged

55 tasks

kYc0o modified the milestones: Release 2016.10, Release 2016.07 Jul 22, 2016

d00616 mentioned this pull request Oct 10, 2016

EEPROM simulation and Flash access. sandeepmistry/arduino-nRF5#50

Closed

miri64 modified the milestones: Release 2017.01, Release 2016.10 Oct 31, 2016

miri64 closed this Jan 24, 2017

miri64 added the State: archived State: The PR has been archived for possible future re-adaptation label Jan 24, 2017

jnohlgard added the Area: fs Area: File systems label Feb 19, 2018

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Flash interface #2239

Flash interface #2239

d00616 commented Jan 3, 2015

LudwigKnuepfer commented Jan 4, 2015

LudwigKnuepfer Jan 4, 2015

d00616 commented Jan 4, 2015

LudwigKnuepfer commented Jan 4, 2015

d00616 Jan 6, 2015

PeterKietzmann commented Mar 23, 2016

kYc0o commented Mar 23, 2016

OlegHahm commented Mar 23, 2016

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kYc0o commented Jul 22, 2016

miri64 commented Sep 27, 2016

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haukepetersen commented Jan 16, 2017

kYc0o commented Jan 16, 2017

miri64 commented Jan 24, 2017

Flash interface #2239

Flash interface #2239

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d00616 commented Jan 3, 2015

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