How to read data by using fstorage

RE: How to read data by using fstorage

bjorn-spockeli — Fri, 05 May 2017 09:18:01 GMT

Yes, this is what i wrote a couple of comments up:

You can store your data chunks at a specific flash address so that you know where to retrieve the data by dereferencing the pointer to that specific flash address.

RE: How to read data by using fstorage

dingari — Fri, 05 May 2017 09:15:41 GMT

One thing that is not clear in your example is that the p_start_addr pointer can be set manually, according to the docs. So instead of pstorage_load you have to specify a place in flash, assign p_start_addr to point to that address, and dereference that pointer to load the data?

RE: How to read data by using fstorage

bjorn-spockeli — Fri, 05 May 2017 07:17:56 GMT

@Abe: Yes, that is correct.

RE: How to read data by using fstorage

Abe — Thu, 04 May 2017 13:50:11 GMT

@BjørnSpockeli: So, just to be clear, the fstorage module does not support any functionalities apart from storing and erasing data. Then is the Flash Data Storage module the API to use for functionalities revolving around both, storing and retrieving data from Flash just like pstorage module?

RE: How to read data by using fstorage

bjorn-spockeli — Thu, 04 May 2017 13:21:35 GMT

@abeshek: Firstly, fstorage is the replacement of pstorage, i.e. the fstorage module provides the functionality to store data to flash and erase flash pages just like pstorage. Nothing more and nothing less. You can store your data chunks at a specific flash address so that you know where to retrieve the data by dereferencing the pointer to that specific flash address.

RE: How to read data by using fstorage

Abe — Thu, 04 May 2017 13:07:43 GMT

@BjørnSpockeli Can you please be kind enough as to respond to the message chain and clear out any confusions that are lingering around the capabilities of fstorage module - to load,update,store,and erase the persistent data? Also, speaking from a end-user's perspective it would be highly inefficient if fstorage - a higher and advanced version of pstorage module, is not able to support the basic and developer friendly techniques of storing and loading the chunks of data.

RE: How to read data by using fstorage

Anuj C — Fri, 31 Mar 2017 09:14:14 GMT

@siddhantmodi There is no flaw. In the "Experimental: Flash Storage" documentation for SDK 11 if you look at the section "Priority for Flash Usage" you'll see how it works. You assign each chunk of registered flash memory a priority when you configure it. Assuming the contents of the flash do not change between restarts, the chunk with the same priority will always be assigned to the same memory location. You also cannot change the number of pages dedicated to each chunk as this would mess up the spacing.

RE: How to read data by using fstorage

dingari — Wed, 15 Mar 2017 10:41:32 GMT

Is there really not a way of simply loading data using the fstorage module? It seems really unthought, given that pstorage has been deprecated. The module that is supposed to replace it doesn't provide the same functionality?

Anyway. In my application I have to store a single struct and retrieve it on startup. I don't want to use a complicated Flash Data Storage with files and records. I ended up using your way with a dummy word that I write to and retrieve the data from the pointer upon getting the completed event.

But that's a rather silly workaround for a flash storage module...

RE: How to read data by using fstorage

Kapil Rawat — Mon, 20 Feb 2017 11:47:03 GMT

You also need to erase previous value if you updating value, i.e.

{

fs_erase(&fs_config, fs_config.p_start_addr, 1);

}

RE: How to read data by using fstorage

summer — Tue, 24 Jan 2017 09:49:03 GMT

@Bjørn Spockeli any updates here?

RE: How to read data by using fstorage

Sid Modi — Thu, 01 Dec 2016 00:54:25 GMT

@Bjørn Spockeli: Has a way to overcome this logic flaw been found? I was looking at the latest version of the sdk and it looks like the problem persists.

Thanks!

Cheers, Sid

RE: How to read data by using fstorage

Dave_couling — Thu, 13 Oct 2016 19:32:53 GMT

Hi Bjorn,

Wouldn't the values in the Section Variables still be lost after a power-cycle?

RE: How to read data by using fstorage

bjorn-spockeli — Tue, 11 Oct 2016 07:32:21 GMT

@dave_couling: Yes, I agree that my example has a major logic flaw. I think this has been addressed by the Section Variables feature in the latest releases of the SDK.

RE: How to read data by using fstorage

Dave_couling — Thu, 06 Oct 2016 00:57:04 GMT

Does this not have a logic FLAW? If you lose power, you will lose the data pointers to the Flash memory locations. Therefore you will not be able to retrieve Flash data after a power-cycle, only after first saving and retrieving the pointer.

RE: How to read data by using fstorage

dblasco — Mon, 12 Sep 2016 13:17:00 GMT

Dear Bjorn,

I understand your way to read data. But this way you are forced to overwrite your data before being able to read it, right? How can you access the pointer without modifying the saved data? Thank you

RE: How to read data by using fstorage

Pavan kumar — Wed, 20 Apr 2016 10:38:24 GMT

OOh ok I think its better if you have any. Any how that's fine and thanks for ans

RE: How to read data by using fstorage

bjorn-spockeli — Wed, 20 Apr 2016 10:36:14 GMT

There is no load API call, you have to keep track of the pointer after you store the data.

RE: How to read data by using fstorage

Pavan kumar — Wed, 20 Apr 2016 09:54:50 GMT

Thanks Bjorn for replying. I already come to know that I can use the data by using pointer but my question is just like in pstorage we have any call that can return the data required

Thanks&regards Pavan

RE: How to read data by using fstorage

bjorn-spockeli — Thu, 31 Mar 2016 10:46:22 GMT

After calling fs_store() you will receive the FS_EVT_STORE event in the fs_evt_handler() when the flash operation is finished. Within the fs_evt_t structure you'll find the pointer to the data that was written to flash.

To retrieve the data, you must create a pointer variable that should be used to store the pointer that points to the data in flash, i.e.

const uint32_t * stored_data;

and when you get the FS_EVT_STORE, simply set the pointer to point to the same address as the pointer that is returned in the fs_evt_handler(), i.e.

static void fs_evt_handler(fs_evt_t const * const evt, fs_ret_t result)
{
    switch(evt->id)
    {
        case FS_EVT_STORE:
            if(result == FS_SUCCESS)
            {
                stored_data = evt->store.p_data;
                SEGGER_RTT_printf(0,"Stored Data: %X \n",*stored_data);
            }
            break;
        
        case FS_EVT_ERASE:
            // Handle erase event
            break;
        
        default:
            //Do nothing
            break;
    }
}

This is provided that you run the following code snippet in main()

FS_REGISTER_CFG(fs_config_t fs_config) =
    {
        .callback  = fs_evt_handler,    // Function for event callbacks.
        .num_pages = 1,                 // Number of physical flash pages required.
        .priority  = 0xFE               // Priority for flash usage.
    };

fs_ret_t ret = fs_init();
if (ret != FS_SUCCESS)
{
    SEGGER_RTT_printf(0,"FS ERROR OCCURED\n");
    // An error occurred.
}

//Data to be written to flash
static uint32_t data = 0x12345678;

ret = fs_store(&fs_config, fs_config.p_start_addr, &data, 1);
if (ret != FS_SUCCESS)
{
     SEGGER_RTT_printf(0,"FS ERROR OCCURED\n");
    // An error occurred.
}

and that you have added the fs_sys_event_handler() function in sys_evt_dispatch(), i.e.

static void sys_evt_dispatch(uint32_t sys_evt)
{
    ble_advertising_on_sys_evt(sys_evt);
    fs_sys_event_handler(sys_evt);
}

-Bjørn