LibrePilot/flight/pios/stm32f4xx/pios_usb_hid.c

/**
 ******************************************************************************
 * @addtogroup PIOS PIOS Core hardware abstraction layer
 * @{
 * @addtogroup   PIOS_USB_HID USB COM Functions
 * @brief PIOS USB COM implementation for HID interfaces
 * @notes      This implements serial emulation over HID reports
 * @{
 *
 * @file       pios_usb_hid.c
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
 * @brief      USB COM functions (STM32 dependent code)
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * This program 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "pios.h"

#ifdef PIOS_INCLUDE_USB_HID

#include "pios_usb_hid_priv.h"
#include "pios_usb_board_data.h" /* PIOS_BOARD_*_DATA_LENGTH */
#include "pios_usbhook.h" /* PIOS_USBHOOK_* */

static void PIOS_USB_HID_RegisterTxCallback(uint32_t usbhid_id, pios_com_callback tx_out_cb, uint32_t context);
static void PIOS_USB_HID_RegisterRxCallback(uint32_t usbhid_id, pios_com_callback rx_in_cb, uint32_t context);
static void PIOS_USB_HID_TxStart(uint32_t usbhid_id, uint16_t tx_bytes_avail);
static void PIOS_USB_HID_RxStart(uint32_t usbhid_id, uint16_t rx_bytes_avail);

const struct pios_com_driver pios_usb_hid_com_driver = {
    .tx_start   = PIOS_USB_HID_TxStart,
    .rx_start   = PIOS_USB_HID_RxStart,
    .bind_tx_cb = PIOS_USB_HID_RegisterTxCallback,
    .bind_rx_cb = PIOS_USB_HID_RegisterRxCallback,
    .available  = PIOS_USB_CheckAvailable,
};

enum pios_usb_hid_dev_magic {
    PIOS_USB_HID_DEV_MAGIC = 0xAA00BB00,
};

struct pios_usb_hid_dev {
    enum pios_usb_hid_dev_magic   magic;
    const struct pios_usb_hid_cfg *cfg;

    uint32_t lower_id;

    pios_com_callback rx_in_cb;
    uint32_t rx_in_context;
    pios_com_callback tx_out_cb;
    uint32_t tx_out_context;

    bool     usb_if_enabled;

    uint8_t  rx_packet_buffer[PIOS_USB_BOARD_HID_DATA_LENGTH] __attribute__((aligned(4)));
    bool     rx_active;

    uint8_t  tx_packet_buffer[PIOS_USB_BOARD_HID_DATA_LENGTH] __attribute__((aligned(4)));
    bool     tx_active;

    uint32_t rx_dropped;
    uint32_t rx_oversize;
};

static bool PIOS_USB_HID_validate(struct pios_usb_hid_dev *usb_hid_dev)
{
    return usb_hid_dev && (usb_hid_dev->magic == PIOS_USB_HID_DEV_MAGIC);
}

#if defined(PIOS_INCLUDE_FREERTOS)
static struct pios_usb_hid_dev *PIOS_USB_HID_alloc(void)
{
    struct pios_usb_hid_dev *usb_hid_dev;

    usb_hid_dev = (struct pios_usb_hid_dev *)pvPortMalloc(sizeof(struct pios_usb_hid_dev));
    if (!usb_hid_dev) {
        return NULL;
    }

    memset(usb_hid_dev, 0, sizeof(struct pios_usb_hid_dev));
    usb_hid_dev->magic = PIOS_USB_HID_DEV_MAGIC;
    return usb_hid_dev;
}
#else
static struct pios_usb_hid_dev pios_usb_hid_devs[PIOS_USB_HID_MAX_DEVS];
static uint8_t pios_usb_hid_num_devs;
static struct pios_usb_hid_dev *PIOS_USB_HID_alloc(void)
{
    struct pios_usb_hid_dev *usb_hid_dev;

    if (pios_usb_hid_num_devs >= PIOS_USB_HID_MAX_DEVS) {
        return NULL;
    }

    usb_hid_dev = &pios_usb_hid_devs[pios_usb_hid_num_devs++];

    memset(usb_hid_dev, 0, sizeof(struct pios_usb_hid_dev));
    usb_hid_dev->magic = PIOS_USB_HID_DEV_MAGIC;

    return usb_hid_dev;
}
#endif /* if defined(PIOS_INCLUDE_FREERTOS) */

static void PIOS_USB_HID_IF_Init(uint32_t usb_hid_id);
static void PIOS_USB_HID_IF_DeInit(uint32_t usb_hid_id);
static bool PIOS_USB_HID_IF_Setup(uint32_t usb_hid_id, struct usb_setup_request *req);
static void PIOS_USB_HID_IF_CtrlDataOut(uint32_t usb_hid_id, const struct usb_setup_request *req);

static struct pios_usb_ifops usb_hid_ifops = {
    .init   = PIOS_USB_HID_IF_Init,
    .deinit = PIOS_USB_HID_IF_DeInit,
    .setup  = PIOS_USB_HID_IF_Setup,
    .ctrl_data_out = PIOS_USB_HID_IF_CtrlDataOut,
};

static bool PIOS_USB_HID_EP_IN_Callback(uint32_t usb_hid_id, uint8_t epnum, uint16_t len);
static bool PIOS_USB_HID_EP_OUT_Callback(uint32_t usb_hid_id, uint8_t epnum, uint16_t len);

int32_t PIOS_USB_HID_Init(uint32_t *usbhid_id, const struct pios_usb_hid_cfg *cfg, uint32_t lower_id)
{
    PIOS_Assert(usbhid_id);
    PIOS_Assert(cfg);

    struct pios_usb_hid_dev *usb_hid_dev;

    usb_hid_dev = (struct pios_usb_hid_dev *)PIOS_USB_HID_alloc();
    if (!usb_hid_dev) {
        goto out_fail;
    }

    /* Bind the configuration to the device instance */
    usb_hid_dev->cfg = cfg;
    usb_hid_dev->lower_id  = lower_id;

    /* Rx and Tx are not active yet */
    usb_hid_dev->rx_active = false;
    usb_hid_dev->tx_active = false;

    /* Register class specific interface callbacks with the USBHOOK layer */
    usb_hid_dev->usb_if_enabled = false;
    PIOS_USBHOOK_RegisterIfOps(cfg->data_if, &usb_hid_ifops, (uint32_t)usb_hid_dev);

    *usbhid_id = (uint32_t)usb_hid_dev;

    return 0;

out_fail:
    return -1;
}


static struct pios_usbhook_descriptor hid_desc;

void PIOS_USB_HID_RegisterHidDescriptor(const uint8_t *desc, uint16_t length)
{
    hid_desc.descriptor = desc;
    hid_desc.length     = length;
}

static struct pios_usbhook_descriptor hid_report_desc;

void PIOS_USB_HID_RegisterHidReport(const uint8_t *desc, uint16_t length)
{
    hid_report_desc.descriptor = desc;
    hid_report_desc.length     = length;
}

static bool PIOS_USB_HID_SendReport(struct pios_usb_hid_dev *usb_hid_dev)
{
    uint16_t bytes_to_tx;

    if (!usb_hid_dev->tx_out_cb) {
        return false;
    }

    bool need_yield = false;
#ifdef PIOS_USB_BOARD_BL_HID_HAS_NO_LENGTH_BYTE
    bytes_to_tx = (usb_hid_dev->tx_out_cb)(usb_hid_dev->tx_out_context,
                                           &usb_hid_dev->tx_packet_buffer[1],
                                           sizeof(usb_hid_dev->tx_packet_buffer) - 1,
                                           NULL,
                                           &need_yield);
#else
    bytes_to_tx = (usb_hid_dev->tx_out_cb)(usb_hid_dev->tx_out_context,
                                           &usb_hid_dev->tx_packet_buffer[2],
                                           sizeof(usb_hid_dev->tx_packet_buffer) - 2,
                                           NULL,
                                           &need_yield);
#endif
    if (bytes_to_tx == 0) {
        return false;
    }

    /*
     * Mark this endpoint as being tx active _before_ actually transmitting
     * to make sure we don't race with the Tx completion interrupt
     */
    usb_hid_dev->tx_active = true;

    /* Always set type as report ID */
    usb_hid_dev->tx_packet_buffer[0] = 1;

#ifdef PIOS_USB_BOARD_BL_HID_HAS_NO_LENGTH_BYTE
    PIOS_USBHOOK_EndpointTx(usb_hid_dev->cfg->data_tx_ep,
                            usb_hid_dev->tx_packet_buffer,
                            sizeof(usb_hid_dev->tx_packet_buffer));
#else
    usb_hid_dev->tx_packet_buffer[1] = bytes_to_tx;
    PIOS_USBHOOK_EndpointTx(usb_hid_dev->cfg->data_tx_ep,
                            usb_hid_dev->tx_packet_buffer,
                            sizeof(usb_hid_dev->tx_packet_buffer));
#endif

#if defined(PIOS_INCLUDE_FREERTOS)
    if (need_yield) {
        vPortYieldFromISR();
    }
#endif /* PIOS_INCLUDE_FREERTOS */

    return true;
}

static void PIOS_USB_HID_RxStart(uint32_t usbhid_id, uint16_t rx_bytes_avail)
{
    struct pios_usb_hid_dev *usb_hid_dev = (struct pios_usb_hid_dev *)usbhid_id;

    bool valid = PIOS_USB_HID_validate(usb_hid_dev);

    PIOS_Assert(valid);

    /* Make sure this USB interface has been initialized */
    if (!usb_hid_dev->usb_if_enabled) {
        return;
    }

    if (!PIOS_USB_CheckAvailable(usb_hid_dev->lower_id)) {
        return;
    }

    // If endpoint was stalled and there is now space make it valid
#ifdef PIOS_USB_BOARD_BL_HID_HAS_NO_LENGTH_BYTE
    uint16_t max_payload_length = PIOS_USB_BOARD_HID_DATA_LENGTH - 1;
#else
    uint16_t max_payload_length = PIOS_USB_BOARD_HID_DATA_LENGTH - 2;
#endif

    if (!usb_hid_dev->rx_active && (rx_bytes_avail >= max_payload_length)) {
        PIOS_USBHOOK_EndpointRx(usb_hid_dev->cfg->data_rx_ep,
                                usb_hid_dev->rx_packet_buffer,
                                sizeof(usb_hid_dev->rx_packet_buffer));
        usb_hid_dev->rx_active = true;
    }
}

static void PIOS_USB_HID_TxStart(uint32_t usbhid_id, __attribute__((unused)) uint16_t tx_bytes_avail)
{
    struct pios_usb_hid_dev *usb_hid_dev = (struct pios_usb_hid_dev *)usbhid_id;

    bool valid = PIOS_USB_HID_validate(usb_hid_dev);

    PIOS_Assert(valid);

    /* Make sure this USB interface has been initialized */
    if (!usb_hid_dev->usb_if_enabled) {
        return;
    }

    if (!PIOS_USB_CheckAvailable(usb_hid_dev->lower_id)) {
        return;
    }

    if (!usb_hid_dev->tx_active) {
        /* Transmitter is not currently active, send a report */
        PIOS_USB_HID_SendReport(usb_hid_dev);
    }
}

static void PIOS_USB_HID_RegisterRxCallback(uint32_t usbhid_id, pios_com_callback rx_in_cb, uint32_t context)
{
    struct pios_usb_hid_dev *usb_hid_dev = (struct pios_usb_hid_dev *)usbhid_id;

    bool valid = PIOS_USB_HID_validate(usb_hid_dev);

    PIOS_Assert(valid);

    /*
     * Order is important in these assignments since ISR uses _cb
     * field to determine if it's ok to dereference _cb and _context
     */
    usb_hid_dev->rx_in_context = context;
    usb_hid_dev->rx_in_cb = rx_in_cb;
}

static void PIOS_USB_HID_RegisterTxCallback(uint32_t usbhid_id, pios_com_callback tx_out_cb, uint32_t context)
{
    struct pios_usb_hid_dev *usb_hid_dev = (struct pios_usb_hid_dev *)usbhid_id;

    bool valid = PIOS_USB_HID_validate(usb_hid_dev);

    PIOS_Assert(valid);

    /*
     * Order is important in these assignments since ISR uses _cb
     * field to determine if it's ok to dereference _cb and _context
     */
    usb_hid_dev->tx_out_context = context;
    usb_hid_dev->tx_out_cb = tx_out_cb;
}

static void PIOS_USB_HID_IF_Init(uint32_t usb_hid_id)
{
    struct pios_usb_hid_dev *usb_hid_dev = (struct pios_usb_hid_dev *)usb_hid_id;

    if (!PIOS_USB_HID_validate(usb_hid_dev)) {
        return;
    }

    /* Register endpoint specific callbacks with the USBHOOK layer */
    PIOS_USBHOOK_RegisterEpInCallback(usb_hid_dev->cfg->data_tx_ep,
                                      sizeof(usb_hid_dev->tx_packet_buffer),
                                      PIOS_USB_HID_EP_IN_Callback,
                                      (uint32_t)usb_hid_dev);
    PIOS_USBHOOK_RegisterEpOutCallback(usb_hid_dev->cfg->data_rx_ep,
                                       sizeof(usb_hid_dev->rx_packet_buffer),
                                       PIOS_USB_HID_EP_OUT_Callback,
                                       (uint32_t)usb_hid_dev);
    usb_hid_dev->usb_if_enabled = true;
    usb_hid_dev->tx_active = false;
    usb_hid_dev->rx_active = false;
}

static void PIOS_USB_HID_IF_DeInit(uint32_t usb_hid_id)
{
    struct pios_usb_hid_dev *usb_hid_dev = (struct pios_usb_hid_dev *)usb_hid_id;

    if (!PIOS_USB_HID_validate(usb_hid_dev)) {
        return;
    }

    /* DeRegister endpoint specific callbacks with the USBHOOK layer */
    usb_hid_dev->usb_if_enabled = false;
    usb_hid_dev->tx_active = false;
    usb_hid_dev->rx_active = false;
    PIOS_USBHOOK_DeRegisterEpInCallback(usb_hid_dev->cfg->data_tx_ep);
    PIOS_USBHOOK_DeRegisterEpOutCallback(usb_hid_dev->cfg->data_rx_ep);
}

static uint8_t hid_protocol;
static uint8_t hid_altset;

struct hid_idle_msg {
    uint8_t idle_period;
    uint8_t report_id;
};
static struct hid_idle_msg hid_idle;
static uint8_t dummy_report[2];

static bool PIOS_USB_HID_IF_Setup(uint32_t usb_hid_id, struct usb_setup_request *req)
{
    struct pios_usb_hid_dev *usb_hid_dev = (struct pios_usb_hid_dev *)usb_hid_id;

    if (!PIOS_USB_HID_validate(usb_hid_dev)) {
        return false;
    }

    /* Make sure this is a request for an interface we know about */
    uint8_t ifnum = req->wIndex & 0xFF;
    if (ifnum != usb_hid_dev->cfg->data_if) {
        return false;
    }

    switch (req->bmRequestType & (USB_REQ_TYPE_MASK | USB_REQ_RECIPIENT_MASK)) {
    case (USB_REQ_TYPE_STANDARD | USB_REQ_RECIPIENT_INTERFACE):
        switch (req->bRequest) {
        case USB_REQ_GET_DESCRIPTOR:
            switch (req->wValue >> 8) {
            case USB_DESC_TYPE_REPORT:
                PIOS_USBHOOK_CtrlTx(hid_report_desc.descriptor,
                                    MIN(hid_report_desc.length, req->wLength));
                break;
            case USB_DESC_TYPE_HID:
                PIOS_USBHOOK_CtrlTx(hid_desc.descriptor,
                                    MIN(hid_desc.length, req->wLength));
                break;
            default:
                /* Unhandled descriptor request */
                return false;

                break;
            }
            break;
        case USB_REQ_GET_INTERFACE:
            PIOS_USBHOOK_CtrlTx(&hid_altset, 1);
            break;
        case USB_REQ_SET_INTERFACE:
            hid_altset = (uint8_t)(req->wValue);
            break;
        default:
            /* Unhandled standard request */
            return false;

            break;
        }
        break;
    case (USB_REQ_TYPE_CLASS | USB_REQ_RECIPIENT_INTERFACE):
        switch (req->bRequest) {
        case USB_HID_REQ_SET_PROTOCOL:
            hid_protocol = (uint8_t)(req->wValue);
            break;
        case USB_HID_REQ_SET_IDLE:
            /* Idle rates are currently ignored but decoded for debugging */
            hid_idle.idle_period = req->wValue & 0xFF00 >> 8;
            hid_idle.report_id   = req->wValue & 0x00FF;
            break;
        case USB_HID_REQ_GET_PROTOCOL:
            PIOS_USBHOOK_CtrlTx(&hid_protocol, 1);
            break;
        case USB_HID_REQ_GET_REPORT:
            /* Give back a dummy input report */
            dummy_report[0] = req->wValue & 0xFF; /* Report ID */
            dummy_report[1] = 0x00; /* dummy value */
            PIOS_USBHOOK_CtrlTx(dummy_report,
                                MIN(sizeof(dummy_report), req->wLength));
            break;
        default:
            /* Unhandled class request */
            return false;

            break;
        }
        break;
    default:
        /* Unhandled request */
        return false;
    }

    return true;
}

static void PIOS_USB_HID_IF_CtrlDataOut(__attribute__((unused)) uint32_t usb_hid_id, __attribute__((unused)) const struct usb_setup_request *req)
{
    /* HID devices don't have any OUT data stages on the control endpoint */
    PIOS_Assert(0);
}

/**
 * @brief Callback used to indicate a transmission from device INto host completed
 * Checks if any data remains, pads it into HID packet and sends.
 */
static bool PIOS_USB_HID_EP_IN_Callback(uint32_t usb_hid_id, __attribute__((unused)) uint8_t epnum, __attribute__((unused)) uint16_t len)
{
    struct pios_usb_hid_dev *usb_hid_dev = (struct pios_usb_hid_dev *)usb_hid_id;

    if (!PIOS_USB_HID_validate(usb_hid_dev)) {
        return false;
    }

    if (PIOS_USB_CheckAvailable(usb_hid_dev->lower_id) &&
        PIOS_USB_HID_SendReport(usb_hid_dev)) {
        /* More data has been queued, leave tx_active set to true */
        return true;
    } else {
        /* Nothing new sent, transmitter is now inactive */
        usb_hid_dev->tx_active = false;
        return false;
    }
}

/**
 * EP1 OUT Callback Routine
 */
static bool PIOS_USB_HID_EP_OUT_Callback(uint32_t usb_hid_id, __attribute__((unused)) uint8_t epnum, uint16_t len)
{
    struct pios_usb_hid_dev *usb_hid_dev = (struct pios_usb_hid_dev *)usb_hid_id;

    if (!PIOS_USB_HID_validate(usb_hid_dev)) {
        return false;
    }

    if (len > sizeof(usb_hid_dev->rx_packet_buffer)) {
        len = sizeof(usb_hid_dev->rx_packet_buffer);
    }

    if (!usb_hid_dev->rx_in_cb) {
        /* No Rx call back registered, disable the receiver */
        usb_hid_dev->rx_active = false;
        return false;
    }

    /* The first byte is report ID (not checked), the second byte is the valid data length */
    uint16_t headroom;
    bool need_yield = false;
#ifdef PIOS_USB_BOARD_BL_HID_HAS_NO_LENGTH_BYTE
    (usb_hid_dev->rx_in_cb)(usb_hid_dev->rx_in_context,
                            &usb_hid_dev->rx_packet_buffer[1],
                            len - 1,
                            &headroom,
                            &need_yield);
#else
    (usb_hid_dev->rx_in_cb)(usb_hid_dev->rx_in_context,
                            &usb_hid_dev->rx_packet_buffer[2],
                            usb_hid_dev->rx_packet_buffer[1],
                            &headroom,
                            &need_yield);
#endif

#ifdef PIOS_USB_BOARD_BL_HID_HAS_NO_LENGTH_BYTE
    uint16_t max_payload_length = PIOS_USB_BOARD_HID_DATA_LENGTH - 1;
#else
    uint16_t max_payload_length = PIOS_USB_BOARD_HID_DATA_LENGTH - 2;
#endif

    bool rc;
    if (headroom >= max_payload_length) {
        /* We have room for a maximum length message */
        PIOS_USBHOOK_EndpointRx(usb_hid_dev->cfg->data_rx_ep,
                                usb_hid_dev->rx_packet_buffer,
                                sizeof(usb_hid_dev->rx_packet_buffer));
        rc = true;
    } else {
        /* Not enough room left for a message, apply backpressure */
        usb_hid_dev->rx_active = false;
        rc = false;
    }

#if defined(PIOS_INCLUDE_FREERTOS)
    if (need_yield) {
        vPortYieldFromISR();
    }
#endif /* PIOS_INCLUDE_FREERTOS */

    return rc;
}

#endif /* PIOS_INCLUDE_USB_HID */