[ECOS] I2C Bus definition problem

[ECOS] I2C Bus definition problem

[Alexandre]

Hi everybody,

I'm near the end in my attempt to make an I2C driver for the LPC2XXX platform.
I'm trying to declare my i2c bus using the I2C generic macro CYG_I2C_BUS
Currently the declaration looks like this:

CYG_I2C_BUS(i2cBusLpc, cyg_lpc2xxx_i2c_init, cyg_lpc2xxx_i2c_tx,
cyg_lpc2xxx_i2c_rx, cyg_lpc2xxx_i2c_stop, ((void*)(&extra)) 	);

'extra' being declared two lines above like this:

static cyg_lpc2xxx_i2c_extra extra;

When I try to compile the code, the compiler says for the line where I
use the macro:

'section attribute cannot be specified for local variables'

I tried to look over the internet for hints on that error and found
nothing but error logs with the same error and nothing to get rid of
it.

Does someone have an idea of what i'm doing wrong ?

PS: For those of you unfamiliar with the ecos I2C interface, here is
what the declaration of the I2C bus structure looks like:

typedef struct cyg_i2c_bus {
    cyg_drv_mutex_t         i2c_lock;
#ifdef CYGDBG_USE_ASSERTS
    const cyg_i2c_device*   i2c_current_device;
#endif
    // The hardware-specific functions that do the real work
    void                    (*i2c_init_fn)(struct cyg_i2c_bus*);
    cyg_uint32              (*i2c_tx_fn)(const cyg_i2c_device*,
cyg_bool, const cyg_uint8*, cyg_uint32, cyg_bool);
    cyg_uint32              (*i2c_rx_fn)(const cyg_i2c_device*,
cyg_bool, cyg_uint8*, cyg_uint32, cyg_bool, cyg_bool);
    void                    (*i2c_stop_fn)(const cyg_i2c_device*);
    // A spare field for use by the driver
    void*                   i2c_extra;
} CYG_HAL_TABLE_TYPE cyg_i2c_bus;

And the declaration macro:

#define CYG_I2C_BUS(_name_, _init_fn_, _tx_fn_, _rx_fn_, _stop_fn_,
_extra_)    \
    cyg_i2c_bus _name_  CYG_HAL_TABLE_ENTRY( i2c_buses ) = {
         \
        .i2c_init_fn    = _init_fn_,
         \
        .i2c_tx_fn      = _tx_fn_,
         \
        .i2c_rx_fn      = _rx_fn_,
         \
        .i2c_stop_fn    = _stop_fn_,
         \
        .i2c_extra      = _extra_
         \
    }

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Re: [ECOS] I2C Bus definition problem

[Andrew Lunn]

On Fri, Sep 07, 2007 at 12:23:17PM +0200, Alexandre wrote:
> Hi everybody,
> 
> I'm near the end in my attempt to make an I2C driver for the LPC2XXX platform.
> I'm trying to declare my i2c bus using the I2C generic macro CYG_I2C_BUS
> Currently the declaration looks like this:
> 
> CYG_I2C_BUS(i2cBusLpc, cyg_lpc2xxx_i2c_init, cyg_lpc2xxx_i2c_tx,
> cyg_lpc2xxx_i2c_rx, cyg_lpc2xxx_i2c_stop, ((void*)(&extra)) 	);
> 
> 'extra' being declared two lines above like this:
> 
> static cyg_lpc2xxx_i2c_extra extra;
> 
> When I try to compile the code, the compiler says for the line where I
> use the macro:
> 
> 'section attribute cannot be specified for local variables'

I think this means that one of your variables is on the stack, ie
local. You don't want that! 

Can you send me the file?

    Thanks
        Andrew

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Re: [ECOS] I2C Bus definition problem

[Andrew Lunn]

Hi Alex

Try this:

static cyg_lpc2xxx_i2c_extra extra;

CYG_I2C_BUS(i2cBusLpc,
            cyg_lpc2xxx_i2c_init,
            cyg_lpc2xxx_i2c_tx,
            cyg_lpc2xxx_i2c_rx,
            cyg_lpc2xxx_i2c_stop,
            ((void*)(&extra))
            );

void cyg_user_start(void)
{

  CYG_I2C_DEVICE(i2cDevCamera,
                 &i2cBusLpc,
                 (cyg_uint16)I2C_CAMERA_ADDRESS,
                 (cyg_uint16)0,
                 (cyg_uint32)0
                 );
}

        Andrew

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Re: [ECOS] I2C Bus definition problem

[Alexandre]

Ok it works !

Thank you, do you know what the error is about so ?

On 9/7/07, Andrew Lunn <andrew@lunn.ch> wrote:
> Hi Alex
>
> Try this:
>
> static cyg_lpc2xxx_i2c_extra extra;
>
> CYG_I2C_BUS(i2cBusLpc,
>             cyg_lpc2xxx_i2c_init,
>             cyg_lpc2xxx_i2c_tx,
>             cyg_lpc2xxx_i2c_rx,
>             cyg_lpc2xxx_i2c_stop,
>             ((void*)(&extra))
>             );
>
> void cyg_user_start(void)
> {
>
>   CYG_I2C_DEVICE(i2cDevCamera,
>                  &i2cBusLpc,
>                  (cyg_uint16)I2C_CAMERA_ADDRESS,
>                  (cyg_uint16)0,
>                  (cyg_uint32)0
>                  );
> }
>
>         Andrew
>

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Re: [ECOS] I2C Bus definition problem

[Andrew Lunn]

On Fri, Sep 07, 2007 at 02:53:50PM +0200, Alexandre wrote:
> Ok it works !
> 
> Thank you, do you know what the error is about so ?
> 
> On 9/7/07, Andrew Lunn <andrew@lunn.ch> wrote:
> > Hi Alex
> >
> > Try this:
> >
> > static cyg_lpc2xxx_i2c_extra extra;
> >
> > CYG_I2C_BUS(i2cBusLpc,
> >             cyg_lpc2xxx_i2c_init,
> >             cyg_lpc2xxx_i2c_tx,
> >             cyg_lpc2xxx_i2c_rx,
> >             cyg_lpc2xxx_i2c_stop,
> >             ((void*)(&extra))
> >             );

This declares a variable called i2cBusLpc. Since you have this inside
a function, it is a local variable and so on the stack. However the
macro tries to set attributes which can only be set on global
variables. 

           Andrew

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Re: [ECOS] I2C Bus definition problem

[Alexandre]

Ok, thank you very much for you help :)

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