/* ----------------------------------------------------------------------------
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/*
    Title: USBD implementation for a UDP controller

    About: Purpose
        Implementation of USB device functions on a UDP controller.
*/

//------------------------------------------------------------------------------
//      Headers
//------------------------------------------------------------------------------


#include "USBD.h"
#include "USBDCallbacks.h"
#include <board.h>
#include <pio/pio.h>
#include <utility/trace.h>
#include <utility/led.h>
#include <usb/common/core/USBEndpointDescriptor.h>
#include <usb/common/core/USBGenericRequest.h>

#if defined(BOARD_USB_UDP)

//------------------------------------------------------------------------------
//         Definitions
//------------------------------------------------------------------------------
/*
    Constants: UDP register field values
        UDP_RXDATA - Bit mask for both banks of the UDP_CSR register.
*/
#define UDP_RXDATA              (AT91C_UDP_RX_DATA_BK0 | AT91C_UDP_RX_DATA_BK1)

/*
    Constants: Endpoint states
        UDP_ENDPOINT_DISABLED - Endpoint is disabled.
        UDP_ENDPOINT_HALTED - Endpoint is halted (i.e. STALLs every request).
        UDP_ENDPOINT_IDLE - Endpoint is idle (i.e. ready for transmission).
        UDP_ENDPOINT_SENDING - Endpoint is sending data.
        UDP_ENDPOINT_RECEIVING - Endpoint is receiving data.
*/
#define UDP_ENDPOINT_DISABLED       0
#define UDP_ENDPOINT_HALTED         1
#define UDP_ENDPOINT_IDLE           2
#define UDP_ENDPOINT_SENDING        3
#define UDP_ENDPOINT_RECEIVING      4

/*
    Macros: UDP_CSR register access
        CLEAR_CSR - Clears the specified bit(s) in the UDP_CSR register.
        SET_CSR - Sets the specified bit(s) in the UDP_CSR register.
*/
//#define UDP_CLEAREPFLAGS(pUsb, bEndpoint, dFlags) {
//    CLEAR(UDP_GetDriverInterface(pUsb)->UDP_CSR[bEndpoint], dFlags);
//    while (!ISCLEARED(UDP_GetDriverInterface(pUsb)->UDP_CSR[bEndpoint], dFlags));
//}
#define CLEAR_CSR(endpoint, bits)   AT91C_BASE_UDP->UDP_CSR[endpoint] &= ~bits;
//#define UDP_SETEPFLAGS(pUsb, bEndpoint, dFlags) {
//    while (ISCLEARED(UDP_GetDriverInterface(pUsb)->UDP_CSR[bEndpoint], dFlags))
//        SET(UDP_GetDriverInterface(pUsb)->UDP_CSR[bEndpoint], dFlags);
//}
#define SET_CSR(endpoint, bits)     AT91C_BASE_UDP->UDP_CSR[endpoint] |= bits;

//------------------------------------------------------------------------------
//      Types
//------------------------------------------------------------------------------

/*
    Type: UDP transfer
        Describes an ongoing transfer on a UDP endpoint.

    Variables:
        data - Pointer to a data buffer used for emission/reception.
        buffered - Number of bytes which have been written into the UDP internal
                   FIFO buffers.
        transferred - Number of bytes which have been sent/received.
        remaining - Number of bytes which have not been buffered/transferred yet.
        callback - Optional callback to invoke when the transfer completes.
        argument - Optional argument to the callback function.
*/
typedef struct {

    char *data;
    int buffered;
    int transferred;
    int remaining;
    TransferCallback callback;
    void *argument;

} Transfer;

/*
    Type: UDP endpoint
        Describes the state of an endpoint of the UDP controller.

    Variables:
        state - Current endpoint state.
        bank - Current reception bank (0 or 1).
        size - Maximum packet size for the endpoint.
        transfer - Describes an ongoing transfer (if current state is either
                   <UDP_ENDPOINT_SENDING> or <UDP_ENDPOINT_RECEIVING>).
*/
typedef struct {

    unsigned char state;
    unsigned char bank;
    unsigned short size;
    Transfer transfer;

} Endpoint;

//------------------------------------------------------------------------------
//         Internal variables
//------------------------------------------------------------------------------

/*
    Variables: 
        endpoints - Holds the internal state for each endpoint of the UDP.
        deviceState - Device current state.
        suspended - Indicates if device is currently suspended.
*/
static Endpoint endpoints[BOARD_USB_NUMENDPOINTS];
static unsigned char deviceState;
static unsigned char previousDeviceState;

//------------------------------------------------------------------------------
//      Internal Functions
//------------------------------------------------------------------------------
/*
    Functions: Peripheral clock
        EnablePeripheralClock - Enables the clock of the UDP peripheral.
        DisablePeripheralClock - Disables the UDP peripheral clock.
*/
static inline void UDP_EnablePeripheralClock()
{
    AT91C_BASE_PMC->PMC_PCER = 1 << AT91C_ID_UDP;
}

static inline void UDP_DisablePeripheralClock()
{
    AT91C_BASE_PMC->PMC_PCDR = 1 << AT91C_ID_UDP;
}

/*
    Functions: USB clock
        EnableUsbClock - Enables the 48MHz USB clock.
        DisableUsbClock - Disables the 48MHz USB clock.
*/
static inline void UDP_EnableUsbClock()
{
    AT91C_BASE_PMC->PMC_SCER = AT91C_PMC_UDP;
}

static inline void UDP_DisableUsbClock()
{
    AT91C_BASE_PMC->PMC_SCDR = AT91C_PMC_UDP;
}

/*
    Functions: Transceiver
        UDP_EnableTransceiver - Enables the UDP transceiver.
        UDP_DisableTransceiver - Disables the UDP transceiver.
*/
static inline void UDP_EnableTransceiver()
{
    AT91C_BASE_UDP->UDP_TXVC &= ~AT91C_UDP_TXVDIS;
}

static inline void UDP_DisableTransceiver()
{
    AT91C_BASE_UDP->UDP_TXVC |= AT91C_UDP_TXVDIS;
}

/*
    Function: UDP_EndOfTransfer
        Handles a completed transfer on the given endpoint, invoking the
        configured callback if any.

    Parameters:
        eptnum - Number of the endpoint for which the transfer has completed.
        status - Result of the USB transfer.
*/
static void UDP_EndOfTransfer(unsigned char eptnum, char status)
{
    Endpoint *endpoint = &(endpoints[eptnum]);
    Transfer *transfer = &(endpoint->transfer);

    // Check that endpoint was sending or receiving data
    if ((endpoint->state == UDP_ENDPOINT_RECEIVING)
        || (endpoint->state == UDP_ENDPOINT_SENDING)) {

        trace_LOG(trace_INFO, "EoT ");

        // Endpoint returns in Idle state
        endpoint->state = UDP_ENDPOINT_IDLE;

        // Invoke callback is present
        if (transfer->callback != 0) {

            ((TransferCallback) transfer->callback)
                (transfer->argument,
                 status,
                 transfer->transferred,
                 transfer->remaining + transfer->buffered);
        }
    }
}

/*
    Function: UDP_ClearRxFlag
        Clears the correct reception flag (bank 0 or bank 1) of an endpoint.

    Parameters:
        eptnum - Number of an endpoint.
*/
static void UDP_ClearRxFlag(unsigned char eptnum)
{
    Endpoint *endpoint = &(endpoints[eptnum]);

    // Clear flag and change banks
    if (endpoint->bank == 0) {

        CLEAR_CSR(eptnum, AT91C_UDP_RX_DATA_BK0);

        // Swap bank if in dual-fifo mode
        if (BOARD_USB_ENDPOINTS_BANKS(eptnum) > 1) {

            endpoint->bank = 1;
        }
    }
    else {

        CLEAR_CSR(eptnum, AT91C_UDP_RX_DATA_BK1);
        endpoint->bank = 0;
    }
}

/*
    Function: UDP_WritePayload
        Writes a data payload into the current FIFO buffer of the UDP.

    Parameters:
        eptnum - Number of the endpoint which is sending data.
*/
static void UDP_WritePayload(unsigned char eptnum)
{
    Endpoint *endpoint = &(endpoints[eptnum]);
    Transfer *transfer = &(endpoint->transfer);
    signed int size;

    // Get the number of bytes to send
    size = endpoint->size;
    if (size > transfer->remaining) {

        size = transfer->remaining;
    }

    // Update transfer descriptor information
    transfer->buffered += size;
    transfer->remaining -= size;

    // Write packet in the FIFO buffer
    while (size > 0) {

        AT91C_BASE_UDP->UDP_FDR[eptnum] = *(transfer->data);
        transfer->data++;
        size--;
    }
}

/*
    Function: UDP_ReadPayload
        Reads a data payload from the current FIFO buffer of an endpoint.

    Parameters:
        eptnum - Endpoint number.
        size - Size of the data to read.
*/
static void UDP_ReadPayload(unsigned char eptnum, int size)
{
    Endpoint *endpoint = &(endpoints[eptnum]);
    Transfer *transfer = &(endpoint->transfer);

    // Check that the requested size is not bigger than the remaining transfer
    if (size > transfer->remaining) {

        transfer->buffered += size - transfer->remaining;
        size = transfer->remaining;
    }

    // Update transfer descriptor information
    transfer->remaining -= size;
    transfer->transferred += size;

    // Retrieve packet
    while (size > 0) {

        *(transfer->data) = (char) AT91C_BASE_UDP->UDP_FDR[eptnum];
        transfer->data++;
        size--;
    }
}

/*
    Function: UDP_ReadRequest
        Reads a SETUP request from the FIFO buffer of Control endpoint 0 and
        stores it into the global <request> variable.
*/
static void UDP_ReadRequest(USBGenericRequest *request)
{
    unsigned char *data = (unsigned char *) request;
    unsigned int i;

    // Copy packet
    for (i = 0; i < 8; i++) {

        *data = (unsigned char) AT91C_BASE_UDP->UDP_FDR[0];
        data++;
    }
}

/*
    Function: UDP_ResetEndpoints
        Resets all the endpoints of the UDP peripheral.
*/
static void UDP_ResetEndpoints()
{
    Endpoint *endpoint;
    Transfer *transfer;
    unsigned char eptnum;

    // Reset the transfer descriptor of every endpoint
    for (eptnum = 0; eptnum < BOARD_USB_NUMENDPOINTS; eptnum++) {

        endpoint = &(endpoints[eptnum]);
        transfer = &(endpoint->transfer);

        // Reset endpoint transfer descriptor
        transfer->data = 0;
        transfer->transferred = -1;
        transfer->buffered = -1;
        transfer->remaining = -1;
        transfer->callback = 0;
        transfer->argument = 0;

        // Reset endpoint state
        endpoint->bank = 0;
        endpoint->state = UDP_ENDPOINT_DISABLED;
    }
}

/*
    Function: UDP_DisableEndpoints
        Disables all endpoints of the UDP peripheral except Control endpoint 0.
*/
static void UDP_DisableEndpoints()
{
    unsigned char eptnum;

    // Disable each endpoint, terminating any pending transfer
    for (eptnum = 1; eptnum < BOARD_USB_NUMENDPOINTS; eptnum++) {

        UDP_EndOfTransfer(eptnum, USBD_STATUS_ABORTED);
        endpoints[eptnum].state = UDP_ENDPOINT_DISABLED;
    }
}

/*
    Function: UDP_IsTransferFinished
        Checks if an ongoing transfer on an endpoint has been completed.

    Parameters:
        eptnum - Endpoint number.

    Returns:
        1 if the current transfer on the given endpoint is complete; otherwise
        0.
*/
static unsigned char UDP_IsTransferFinished(unsigned char eptnum)
{
    Endpoint *endpoint = &(endpoints[eptnum]);