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//==========================================================================

//

//      spi.c

//

//      Generic API for accessing devices attached to an SPI bus

//

//==========================================================================

// ####ECOSGPLCOPYRIGHTBEGIN####                                            

// -------------------------------------------                              

// This file is part of eCos, the Embedded Configurable Operating System.   

// Copyright (C) 2004 Free Software Foundation, Inc.                        

//

// eCos is free software; you can redistribute it and/or modify it under    

// the terms of the GNU General Public License as published by the Free     

// Software Foundation; either version 2 or (at your option) any later      

// version.                                                                 

//

// eCos is distributed in the hope that it will be useful, but WITHOUT      

// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or    

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License    

// for more details.                                                        

//

// You should have received a copy of the GNU General Public License        

// along with eCos; if not, write to the Free Software Foundation, Inc.,    

// 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.            

//

// As a special exception, if other files instantiate templates or use      

// macros or inline functions from this file, or you compile this file      

// and link it with other works to produce a work based on this file,       

// this file does not by itself cause the resulting work to be covered by   

// the GNU General Public License. However the source code for this file    

// must still be made available in accordance with section (3) of the GNU   

// General Public License v2.                                               

//

// This exception does not invalidate any other reasons why a work based    

// on this file might be covered by the GNU General Public License.         

// -------------------------------------------                              

// ####ECOSGPLCOPYRIGHTEND####                                              

//==========================================================================

//###DESCRIPTIONBEGIN####

//

// Author(s):     bartv

// Date:          2004-04-23

//

//###DESCRIPTIONEND####

//========================================================================

#include <pkgconf/infra.h>

#include <pkgconf/io_spi.h>

#include <cyg/infra/cyg_ass.h>

#include <cyg/io/spi.h>

// The simple transfer function just calls the transaction functions

// in order. The chip select should be dropped at the end of this

// transfer.

void

cyg_spi_transfer(cyg_spi_device* device, cyg_bool polled, cyg_uint32 count, const cyg_uint8* tx_data, cyg_uint8* rx_data)

{

    cyg_spi_transaction_begin(device);

    cyg_spi_transaction_transfer(device, polled, count, tx_data, rx_data, 1);

    cyg_spi_transaction_end(device);

}

// Tick is similarly simple.

void

cyg_spi_tick(cyg_spi_device* device, cyg_bool polled, cyg_uint32 count)

{

    cyg_spi_transaction_begin(device);

    cyg_spi_transaction_tick(device, polled, count);

    cyg_spi_transaction_end(device);

}

// get_config() and set_config() requires locking the bus, then accessing the

// bus-specific function via the bus structure. Only locking is needed, not

// setting up the bus for a transfer to this device, so the transaction begin

// function is inappropriate.

int

cyg_spi_get_config(cyg_spi_device* device, cyg_uint32 key, void* buf, cyg_uint32* len)

{

    int             result;

    cyg_spi_bus*    bus;

    CYG_CHECK_DATA_PTR(device, "valid SPI device pointer required");

    bus = device->spi_bus;

    CYG_CHECK_DATA_PTR(bus, "SPI device does not point at a valid bus structure");

    CYG_CHECK_FUNC_PTR(bus->spi_get_config, "SPI bus driver has not provided a get_config function");

    while (!cyg_drv_mutex_lock(&(bus->spi_lock)));

    result = (*(bus->spi_get_config))(device, key, buf, len);

    cyg_drv_mutex_unlock(&(bus->spi_lock));

    return result;

}

// set_config is basically just a clone of the above, but using a different

// bus-specific operation.

int

cyg_spi_set_config(cyg_spi_device* device, cyg_uint32 key, const void* buf, cyg_uint32* len)

{

    int             result;

    cyg_spi_bus*    bus;

    CYG_CHECK_DATA_PTR(device, "valid SPI device pointer required");

    bus = device->spi_bus;

    CYG_CHECK_DATA_PTR(bus, "SPI device does not point at a valid bus structure");

    CYG_CHECK_FUNC_PTR(bus->spi_set_config, "SPI bus driver has not provided a set_config function");

    while (!cyg_drv_mutex_lock(&(bus->spi_lock)));

    result = (*(bus->spi_set_config))(device, key, buf, len);

    cyg_drv_mutex_unlock(&(bus->spi_lock));

    return result;

}

// transaction-begin involves getting sole access to the bus, then calling

// the bus driver's begin function to set up the hardware appropriately for

// the target device.

void

cyg_spi_transaction_begin(cyg_spi_device* device)

{

    cyg_spi_bus*    bus;

    CYG_CHECK_DATA_PTR(device, "valid SPI device pointer required");

    bus = device->spi_bus;

    CYG_CHECK_DATA_PTR(bus, "SPI device does not point at a valid bus structure");

    CYG_CHECK_FUNC_PTR(bus->spi_transaction_begin, "SPI device has not provided a transaction_begin function");

    while (!cyg_drv_mutex_lock(&(bus->spi_lock)));

#ifdef CYGDBG_USE_ASSERTS    

    bus->spi_current_device = device;

#endif

    // This thread now has exclusive access to the bus

    (*(bus->spi_transaction_begin))(device);

    // All done. Return with the bus still locked.

}

// A variant of the above which returns immediately if some other thread

// is using the bus.

cyg_bool

cyg_spi_transaction_begin_nb(cyg_spi_device* device)

{

    cyg_bool        result  = false;

    cyg_spi_bus*    bus;

    CYG_CHECK_DATA_PTR(device, "valid SPI device pointer required");

    bus = device->spi_bus;

    CYG_CHECK_DATA_PTR(bus, "SPI device does not point at a valid bus structure");

    CYG_CHECK_FUNC_PTR(bus->spi_transaction_begin, "SPI device has not provided a transaction_begin function");

    if (cyg_drv_mutex_trylock(&(bus->spi_lock))) {

#ifdef CYGDBG_USE_ASSERTS        

        bus->spi_current_device = device;

#endif        

        (*(bus->spi_transaction_begin))(device);

        result = true;

    }

    return result;

}

void

cyg_spi_transaction_transfer(cyg_spi_device* device, cyg_bool polled,

                             cyg_uint32 count, const cyg_uint8* tx_data, cyg_uint8* rx_data,

                             cyg_bool drop_cs)

{

    cyg_spi_bus*    bus;

    CYG_CHECK_DATA_PTR(device, "valid SPI device pointer required");

    bus = device->spi_bus;

    CYG_CHECK_DATA_PTR(bus, "SPI device does not point at a valid bus structure");

    CYG_ASSERT(bus->spi_current_device == device, "SPI transfer requested without claiming the bus");

    CYG_CHECK_FUNC_PTR(bus->spi_transaction_transfer, "SPI device has not provided a transfer function");

    (*(bus->spi_transaction_transfer))(device, polled, count, tx_data, rx_data, drop_cs);

}

void

cyg_spi_transaction_tick(cyg_spi_device* device, cyg_bool polled, cyg_uint32 count)

{

    cyg_spi_bus*    bus;

    CYG_CHECK_DATA_PTR(device, "valid SPI device pointer required");

    bus = device->spi_bus;

    CYG_CHECK_DATA_PTR(bus, "SPI device does not point at a valid bus structure");

    CYG_ASSERT(bus->spi_current_device == device, "SPI ticks requested without claiming the bus");

    CYG_CHECK_FUNC_PTR(bus->spi_transaction_tick, "SPI device has not provided a tick function");

    (*(bus->spi_transaction_tick))(device, polled, count);

}

void

cyg_spi_transaction_end(cyg_spi_device* device)

{

    cyg_spi_bus*    bus;

    CYG_CHECK_DATA_PTR(device, "valid SPI device pointer required");

    bus = device->spi_bus;

    CYG_CHECK_DATA_PTR(bus, "SPI device does not point at a valid bus structure");

    CYG_ASSERT(bus->spi_current_device == device, "SPI transfer requested without claiming the bus");

    CYG_CHECK_FUNC_PTR(bus->spi_transaction_end, "SPI device has not provided an end function");

    // First, call the bus' end function.

    (*(bus->spi_transaction_end))(device);

    // Then release the SPI bus for other threads.

    cyg_drv_mutex_unlock(&(bus->spi_lock));

}