pios_usb_hid.c

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/*
 * 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, see <http://www.gnu.org/licenses/>
 */

/* Project Includes */
#include "pios.h"

#if defined(PIOS_INCLUDE_USB_HID)

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

#define MIN(x,y) (((x) < (y)) ? (x) : (y))
#define MAX(x,y) (((x) > (y)) ? (x) : (y))

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

        uintptr_t lower_id;

        pios_com_callback rx_in_cb;
        uintptr_t rx_in_context;
        pios_com_callback tx_out_cb;
        uintptr_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));
}

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 *)PIOS_malloc(sizeof(*usb_hid_dev));
        if (!usb_hid_dev) return(NULL);

        memset(usb_hid_dev, 0, sizeof(*usb_hid_dev));
        usb_hid_dev->magic = PIOS_USB_HID_DEV_MAGIC;
        return(usb_hid_dev);
}

static void PIOS_USB_HID_IF_Init(uintptr_t usb_hid_id);
static void PIOS_USB_HID_IF_DeInit(uintptr_t usb_hid_id);
static bool PIOS_USB_HID_IF_Setup(uintptr_t usb_hid_id, struct usb_setup_request *req);
static void PIOS_USB_HID_IF_CtrlDataOut(uintptr_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(uintptr_t usb_hid_id, uint8_t epnum, uint16_t len);
static bool PIOS_USB_HID_EP_OUT_Callback(uintptr_t usb_hid_id, uint8_t epnum, uint16_t len);

int32_t PIOS_USB_HID_Init(uintptr_t * usbhid_id, const struct pios_usb_hid_cfg * cfg, uintptr_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, (uintptr_t) usb_hid_dev);

        *usbhid_id = (uintptr_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

        return true;
}

static void PIOS_USB_HID_RxStart(uintptr_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(uintptr_t usbhid_id, 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(uintptr_t usbhid_id, pios_com_callback rx_in_cb, uintptr_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(uintptr_t usbhid_id, pios_com_callback tx_out_cb, uintptr_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(uintptr_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,
                                          (uintptr_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,
                                           (uintptr_t) usb_hid_dev);
        usb_hid_dev->usb_if_enabled = true;

}

static void PIOS_USB_HID_IF_DeInit(uintptr_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;
        }

        /* reset state of the usb hid device structure */
        usb_hid_dev->rx_active = false;
        usb_hid_dev->rx_dropped = 0;
        usb_hid_dev->rx_oversize = 0;
        usb_hid_dev->tx_active = false;
        usb_hid_dev->usb_if_enabled = false;

        /* DeRegister endpoint specific callbacks with the USBHOOK layer */
        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(uintptr_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(uintptr_t usb_hid_id, const struct usb_setup_request *req)
{
        /* HID devices don't have any OUT data stages on the control endpoint */
        PIOS_Assert(0);
}

static bool PIOS_USB_HID_EP_IN_Callback(uintptr_t usb_hid_id, 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 (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;
        }
}

static bool PIOS_USB_HID_EP_OUT_Callback(uintptr_t usb_hid_id, 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;
        }

        return rc;
}

#endif  /* PIOS_INCLUDE_USB_HID */