usb_stm32.c

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#include "cfg/cfg_usb.h"

#define LOG_LEVEL  USB_LOG_LEVEL
#define LOG_FORMAT USB_LOG_FORMAT

#include <cfg/log.h>
#include <cfg/debug.h>
#include <cfg/macros.h>
#include <cfg/module.h>

#include <cpu/irq.h>
#include <cpu/power.h>

#include <drv/irq_cm3.h>
#include <drv/gpio_stm32.h>
#include <drv/clock_stm32.h>
#include <drv/timer.h>
#include <drv/usb.h>

#include <mware/event.h>

#include <string.h> /* memcpy() */

#include "usb_stm32.h"

/* XXX: consider to move this to cfg/macros.h */

/* XXX: redefine this to make it usable within C expression */
#define _MIN(a,b)   (((a) < (b)) ? (a) : (b))

/* STM32 USB registers */
struct stm32_usb
{
    reg32_t EP0R;
    reg32_t EP1R;
    reg32_t EP2R;
    reg32_t EP3R;
    reg32_t EP4R;
    reg32_t EP5R;
    reg32_t EP6R;
    reg32_t EP7R;
    reg32_t __reserved[8];
    reg32_t CNTR;
    reg32_t ISTR;
    reg32_t FNR;
    reg32_t DADDR;
    reg32_t BTABLE;
};

/* Hardware registers */
static struct stm32_usb *usb = (struct stm32_usb *)USB_BASE_ADDR;

/* Endpoint descriptors: used for handling requests to use with endpoints */
static stm32_UsbEp ep_cnfg[EP_MAX_NUM];
STATIC_ASSERT(EP_MAX_NUM <= EP_MAX_HW_NUM);

/* USB EP0 control descriptor */
static const UsbEndpointDesc USB_CtrlEpDescr0 =
{
    .bLength = sizeof(USB_CtrlEpDescr0),
    .bDescriptorType = USB_DT_ENDPOINT,
    .bEndpointAddress = USB_DIR_OUT | 0,
    .bmAttributes = USB_ENDPOINT_XFER_CONTROL,
    .wMaxPacketSize = USB_EP0_MAX_SIZE,
    .bInterval = 0,
};

/* USB EP1 control descriptor */
static const UsbEndpointDesc USB_CtrlEpDescr1 =
{
    .bLength = sizeof(USB_CtrlEpDescr1),
    .bDescriptorType = USB_DT_ENDPOINT,
    .bEndpointAddress = USB_DIR_IN | 0,
    .bmAttributes = USB_ENDPOINT_XFER_CONTROL,
    .wMaxPacketSize = USB_EP0_MAX_SIZE,
    .bInterval = 0,
};

/* USB setup packet */
static UsbCtrlRequest setup_packet;

/* USB device controller: max supported interfaces */
#define USB_MAX_INTERFACE   CONFIG_USB_INTERFACE_MAX

/* USB device controller features */
#define STM32_UDC_FEATURE_SELFPOWERED   BV(0)
#define STM32_UDC_FEATURE_REMOTE_WAKEUP BV(1)

/* Hardware-specific USB device controller structure */
typedef struct stm32_udc
{
    uint8_t state;
    uint32_t cfg_id;
    const UsbConfigDesc *cfg;
    uint32_t interfaces;
    uint32_t alt[USB_MAX_INTERFACE];
    uint32_t address;
    uint8_t feature;
} PACKED stm32_udc_t;

/* Hardware-specific USB Device Controller */
static stm32_udc_t udc;

/* Generic USB Device Controller structure */
static UsbDevice *usb_dev;

/* USB packet memory management: list of allocated chunks */
static stm32_UsbMemSlot *mem_use;

/* USB packet memory management: memory buffer metadata */
static stm32_UsbMemSlot memory_buffer[EP_MAX_NUM];

/* Endpoint TX and RX buffers */
static size_t rx_size, tx_size;

#define EP_BUFFER_SIZE _MIN(CONFIG_USB_BUFSIZE, USB_XFER_MAX_SIZE)
STATIC_ASSERT(!(EP_BUFFER_SIZE & 0x03));

static uint8_t ep_buffer[EP_MAX_NUM][EP_BUFFER_SIZE] ALIGNED(4);

static Event usb_event_done[EP_MAX_SLOTS];

/* Check if we're running in atomic (non-sleepable) context or not */
static volatile bool in_atomic = false;

/* Allocate a free block of the packet memory */
static stm32_UsbMemSlot *usb_malloc(void)
{
    unsigned int i;

    for (i = 0; i < countof(memory_buffer); i++)
        if (memory_buffer[i].Size == 0)
            return &memory_buffer[i];
    return NULL;
}

/* Release a block of the packet memory */
static void usb_free(stm32_UsbMemSlot *pPntr)
{
    pPntr->Size = 0;
}

/* Allocate a free chunk of the packet memory (inside a block) */
static bool usb_alloc_buffer(uint16_t *pOffset, uint32_t *size,
                            int EndPoint)
{
    stm32_UsbMemSlot *mem = mem_use,
            *memNext, *mem_useNew;
    uint32_t max_size = *size;

    /*
     * Packet size alignment:
     *  - fine-granularity allocation: size alignment by 2;
     *  - coarse-granularity allocation: size alignment by 32.
     */
    if (max_size < 62)
        max_size = ALIGN_UP(max_size, 2);
    else
        max_size = ALIGN_UP(max_size, 32);
    /*
     * Finding free memory chunks from the allocated blocks of the USB
     * packet memory.
     */
    *pOffset = 0;
    while (mem != NULL)
    {
        /* Offset alignment by 4 */
        *pOffset = ALIGN_UP(mem->Start + mem->Size, 4);
        memNext = mem->next;
        if ((mem->next == NULL) ||
                (memNext->Start >=
                    *pOffset + max_size))
            break;
        mem = mem->next;
    }
    /* Check for out-of-memory condition */
    if (UNLIKELY((*pOffset + max_size) >= USB_BDT_OFFSET))
        return false;
    /*
     * Allocate a new memory block, next to the last allocated block.
     */
    mem_useNew = usb_malloc();
    if (UNLIKELY(mem_useNew == NULL))
        return false;
    /* Insert the block to the list of allocated blocks */
    if (mem_use == NULL)
    {
        mem_use = mem_useNew;
        mem_use->next = NULL;
    }
    else
    {
        mem_useNew->next = mem->next;
        mem->next = mem_useNew;
    }
    /* Update block's metadata */
    mem_useNew->ep_addr = EndPoint;
    mem_useNew->Start = *pOffset;
    mem_useNew->Size = max_size;

    *size = max_size;

    return true;
}

/* Release a chunk of the packet memory (inside a block) */
static void usb_free_buffer(int EndPoint)
{
    stm32_UsbMemSlot *mem, *memPrev = NULL;
    mem = mem_use;

    while (mem != NULL)
    {
        if (mem->ep_addr == EndPoint)
        {
            if (UNLIKELY(memPrev == NULL))
            {
                /* Free the first element of the list */
                mem_use = mem_use->next;
                usb_free(mem);
                mem = mem_use;
                continue;
            }
            memPrev->next = mem->next;
            usb_free(mem);
        }
        else
            memPrev = mem;
        mem = memPrev->next;
    }
}

/*-------------------------------------------------------------------------*/

/* Connect USB controller */
static void usb_connect(void)
{
    stm32_gpioPinWrite((struct stm32_gpio *)GPIOC_BASE, 1 << 11, 0);
}

/* Set USB device address */
static void usb_set_address(uint32_t addr)
{
    usb->DADDR = addr | 0x80;
}

/* Suspend USB controller */
static void usb_suspend(void)
{
    usb->CNTR |= bmFSUSP | bmLPMODE;
}

/* Resume USB controller */
static void usb_resume(void)
{
    uint32_t line_status;

    line_status = usb->FNR & 0xc000;
    if (!line_status)
        return;
    /* check for noise and eventually return to sleep */
    if (line_status == 0xc000)
        usb_suspend();
    else
        usb->CNTR &= ~(bmFSUSP | bmLPMODE);
}

/* Convert logical EP address to physical EP address */
static int usb_ep_logical_to_hw(uint8_t ep_addr)
{
    int addr = (ep_addr & 0x0f) << 1;
    return (ep_addr & 0x80) ? addr + 1 : addr;
}

/* Set EP address */
static void ep_ctrl_set_ea(reg32_t *reg, uint32_t val)
{
    val &= 0x0f;
    val |= *reg & 0x0700;
    val |= USB_CTRL_CLEAR_ONLY_MASK;
    *reg = val;
}

/* Get EP IN status */
static uint32_t ep_ctrl_get_stat_tx(reg32_t *reg)
{
    return (*reg & (0x3UL << 4)) >> 4;
}

/* Set EP IN state */
static void ep_ctrl_set_stat_tx(reg32_t *reg, stm32_UsbEpState val)
{
    uint32_t state;
    int i;

    /*
     * The EP can change state between read and write operations from VALID
     * to NAK and result of set operation will be invalid.
     */
    for (i = 0; i < 2; i++)
    {
        if (ep_ctrl_get_stat_tx(reg) == val)
            return;
        state = val;
        state <<= 4;
        state ^= *reg;
        state |= USB_CTRL_CLEAR_ONLY_MASK;
        /* Clear the toggle bits without STAT_TX (4,5) */
        state &= ~0x7040;
        *reg = state;
    }
}

/* Set EP DTOG_TX bit (IN) */
static void ep_ctrl_set_dtog_tx(reg32_t *reg, uint32_t val)
{
    val = val ? (*reg ^ (1UL << 6)) : *reg;
    /* Clear the toggle bits without DTOG_TX (6) */
    val &= ~0x7030;
    val |= USB_CTRL_CLEAR_ONLY_MASK;
    *reg = val;
}

/* Clear EP CTR_TX bit (IN) */
static void ep_ctrl_clr_ctr_tx(reg32_t *reg)
{
    uint32_t val = *reg;

    val &= ~(USB_CTRL_TOGGLE_MASK | 1UL << 7);
    /* Set RX_CTR */
    val |= 1UL << 15;
    *reg = val;
}

/* Clear EP CTR_RX bit (OUT) */
static void ep_ctrl_clr_ctr_rx(reg32_t *reg)
{
    uint32_t val = *reg;
    val &= ~(USB_CTRL_TOGGLE_MASK | 1UL << 15);
    /* Set TX_CTR */
    val |= 1UL << 7;
    *reg = val;
}

/* Set EP KIND bit */
static void ep_ctrl_set_ep_kind(reg32_t *reg, uint32_t val)
{
    val = val ? (1UL << 8) : 0;
    val |= *reg & ~(USB_CTRL_TOGGLE_MASK | (1UL << 8));
    val |= USB_CTRL_CLEAR_ONLY_MASK;
    *reg = val;
}

/* Set EP type */
static int ep_ctrl_set_ep_type(reg32_t *reg, uint8_t val)
{
    uint32_t type;

    if (UNLIKELY(val >= EP_TYPE_MAX))
    {
        ASSERT(0);
        return USB_INVAL_ERROR;
    }
    type = val;
    type <<= 9;
    type |= *reg & ~(USB_CTRL_TOGGLE_MASK | (0x3UL << 9));
    type |= USB_CTRL_CLEAR_ONLY_MASK;
    *reg = type;

    return USB_OK;
}

/* Get EP STAT_RX (OUT) */
static uint32_t ep_ctrl_get_stat_rx(reg32_t *reg)
{
    uint32_t val = *reg & (0x3UL << 12);
    return val >> 12;
}

/* Set EP STAT_RX (OUT) */
static void ep_ctrl_set_stat_rx(reg32_t *reg, stm32_UsbEpState val)
{
    uint32_t state;
    int i;

    /*
     * The EP can change state between read and write operations from VALID
     * to NAK and result of set operation will be invalid.
     */
    for (i = 0; i < 2; i++)
    {
        if (ep_ctrl_get_stat_rx(reg) == val)
            return;
        state = val;
        state <<= 12;
        state ^= *reg;
        state |= USB_CTRL_CLEAR_ONLY_MASK;
        /* Clear the toggle bits without STAT_RX (12,13) */
        state &= ~0x4070;
        *reg = state;
    }
}

/* Set DTOG_RX bit */
static void ep_ctrl_set_dtog_rx(reg32_t *reg, uint32_t val)
{
    val = val ? (*reg ^ (1UL << 14)) : *reg;
    /* Clear the toggle bits without DTOG_RX (14) */
    val &= ~0x3070;
    val |= USB_CTRL_CLEAR_ONLY_MASK;
    *reg = val;
}

/* Get EP SETUP bit */
static uint32_t ep_ctrl_get_setup(reg32_t *reg)
{
    uint32_t val = *reg & (1UL << 11);
    return val ? 1 : 0;
}

/* Core endpoint I/O function */
static void __usb_ep_io(int EP)
{
    ssize_t Count, CountHold, Offset;
    uint32_t *pDst, *pSrc, Data;
    stm32_UsbEp *epd = &ep_cnfg[EP];

    if (UNLIKELY(epd->hw == NULL))
    {
        LOG_ERR("%s: invalid endpoint (EP%d-%s)\n",
                __func__,
                EP >> 1,
                (EP & 0x01) ? "IN" : "OUT");
        ASSERT(0);
        return;
    }
    if (epd->status != BEGIN_SERVICED && epd->status != NO_SERVICED)
        return;

    if (EP & 0x01)
    {
        /* EP IN */
        Count = epd->size - epd->offset;
        while (epd->avail_data)
        {
            if (!Count && !(epd->flags & STM32_USB_EP_ZERO_PACKET))
                break;

            /* Set Status */
            epd->status = BEGIN_SERVICED;
            /* Get data size */
            if ((epd->flags & STM32_USB_EP_ZERO_PACKET) &&
                    (Count == epd->max_size))
                epd->flags |= STM32_USB_EP_ZERO_PACKET |
                        STM32_USB_EP_ZERO_POSSIBLE;

            CountHold = Count = MIN(Count, epd->max_size);
            if (!Count)
                epd->flags |= STM32_USB_EP_ZERO_PACKET;
            Offset = epd->offset;
            epd->offset += Count;
            switch (epd->type)
            {
            case USB_ENDPOINT_XFER_CONTROL:
            case USB_ENDPOINT_XFER_INT:
                pDst = (uint32_t *)USB_MEM_ADDR(EP_DTB_READ(EP >> 1, ADDR_TX_OFFSET));
                break;
            case USB_ENDPOINT_XFER_BULK:
                pDst = (uint32_t *)USB_MEM_ADDR(EP_DTB_READ(EP >> 1, ADDR_TX_OFFSET));
                break;
            case USB_ENDPOINT_XFER_ISOC:
                LOG_ERR("%s: isochronous transfer not supported\n",
                    __func__);
                /* Fallback to default */
            default:
                ASSERT(0);
                return;
            }

            /* Write data to packet memory buffer */
            while (Count)
            {
                Data = *(epd->write_buffer + Offset++);
                if (--Count)
                {
                    Data |= (uint32_t)(*(epd->write_buffer + Offset++)) << 8;
                    --Count;
                }
                *pDst++ = Data;
            }

            EP_DTB_WRITE(EP >> 1, COUNT_TX_OFFSET, CountHold);
            ep_ctrl_set_stat_tx(epd->hw, EP_VALID);

            --ep_cnfg[EP].avail_data;
            Count = epd->size - epd->offset;
        }
        if (!Count && !(epd->flags & STM32_USB_EP_ZERO_PACKET))
        {
            epd->status = COMPLETE;
            /* call callback function */
            if (epd->complete)
                epd->complete(EP);
        }
    }
    else
    {
        /* EP OUT */
        while (epd->avail_data)
        {
            /* Get data size and buffer pointer */
            switch (epd->type)
            {
            case USB_ENDPOINT_XFER_CONTROL:
            case USB_ENDPOINT_XFER_INT:
                /* Get received bytes number */
                Count = EP_DTB_READ(EP >> 1, COUNT_RX_OFFSET) & 0x3FF;
                /* Get address of the USB packet buffer for corresponding EP */
                pSrc = (uint32_t *)USB_MEM_ADDR(EP_DTB_READ(EP >> 1, ADDR_RX_OFFSET));
                break;
            case USB_ENDPOINT_XFER_BULK:
                /* Get received bytes number */
                Count = EP_DTB_READ(EP >> 1, COUNT_RX_OFFSET) & 0x3FF;
                /* Get address of the USB packet buffer for corresponding EP */
                pSrc = (uint32_t *)USB_MEM_ADDR(EP_DTB_READ(EP >> 1, ADDR_RX_OFFSET));
                break;
            case USB_ENDPOINT_XFER_ISOC:
                LOG_ERR("%s: isochronous transfer not supported\n",
                    __func__);
                /* Fallback to default */
            default:
                ASSERT(0);
                return;
            }

            if (Count > (epd->size - epd->offset))
            {
                epd->status = BUFFER_OVERRUN;
                epd->size = ep_cnfg[EP].offset;
                break;
            }
            else if (Count < ep_cnfg[EP].max_size)
            {
                epd->status = BUFFER_UNDERRUN;
                epd->size = ep_cnfg[EP].offset + Count;
            }
            else
                epd->status = BEGIN_SERVICED;

            Offset = epd->offset;
            epd->offset += Count;

            /* Read data from packet memory buffer */
            while (Count)
            {
                Data = *pSrc++;
                *(epd->read_buffer + Offset++) = Data;
                if (--Count)
                {
                    Data >>= 8;
                    *(epd->read_buffer + Offset++) = Data;
                    --Count;
                }
            }

            ep_ctrl_set_stat_rx(epd->hw, EP_VALID);

            --ep_cnfg[EP].avail_data;

            if (*epd->hw & (1UL << 11))
            {
                ep_cnfg[EP].status = SETUP_OVERWRITE;
                return;
            }
            if (!(Count = (epd->size - epd->offset)))
            {
                epd->status = COMPLETE;
                break;
            }
        }
        if (epd->status != BEGIN_SERVICED && epd->status != NO_SERVICED)
        {
            /* call callback function */
            if (epd->complete)
                epd->complete(EP);
        }
    }
}

/*
 * Return the lower value from Host expected size and size and set a flag
 * STM32_USB_EP_ZERO_POSSIBLE when size is lower that host expected size.
 */
static size_t usb_size(size_t size, size_t host_size)
{
    if (size < host_size)
    {
        ep_cnfg[CTRL_ENP_IN].flags |= STM32_USB_EP_ZERO_POSSIBLE;
        return size;
    }
    return host_size;
}

/* Configure an EP descriptor before performing a I/O operation */
#define USB_EP_IO(__EP, __op, __buf, __size, __complete)        \
({                                  \
    cpu_flags_t flags;                      \
    stm32_UsbIoStatus ret;                  \
                                    \
    /* Fill EP descriptor */                    \
    IRQ_SAVE_DISABLE(flags);                    \
    if (__size < 0)                         \
    {                               \
        ep_cnfg[__EP].status = NOT_READY;           \
        ep_cnfg[__EP].complete = NULL;              \
        ret = NOT_READY;                    \
        goto out;                       \
    }                               \
    if (ep_cnfg[__EP].status == BEGIN_SERVICED)         \
    {                               \
        ret = NOT_READY;                    \
        goto out;                       \
    }                               \
    /*                              \
     * NOTE: the write_buffer and read_buffer are actually the  \
     * same location in memory (it's a union).          \
     *                              \
     * We have to do this trick to silent a build warning by    \
     * casting the I/O buffer to (void *) or (const void *).    \
     */                             \
    ep_cnfg[__EP].__op ## _buffer = __buf;              \
    ep_cnfg[__EP].offset = 0;                   \
    ep_cnfg[__EP].size = __size;                    \
    ep_cnfg[__EP].complete = __complete;                \
    if (!size)                          \
        ep_cnfg[__EP].flags = STM32_USB_EP_ZERO_PACKET;     \
    else                                \
        ep_cnfg[__EP].flags = 0;                \
    ep_cnfg[__EP].status = NO_SERVICED;             \
                                    \
    /* Perform the I/O operation */                 \
    __usb_ep_io(__EP);                      \
                                    \
    ret = ep_cnfg[__EP].status;                 \
out:                                    \
    IRQ_RESTORE(flags);                     \
    ret;                                \
})

/* Configure and endponint and perform a read operation */
static stm32_UsbIoStatus
__usb_ep_read(int ep, void *buffer, ssize_t size, void (*complete)(int))
{
    if (UNLIKELY((ep >= EP_MAX_NUM) || (ep & 0x01)))
    {
        LOG_ERR("%s: invalid EP number %d\n", __func__, ep);
        ASSERT(0);
        return STALLED;
    }
    if (UNLIKELY((size_t)buffer & 0x03))
    {
        LOG_ERR("%s: unaligned buffer @ %p\n", __func__, buffer);
        ASSERT(0);
        return STALLED;
    }
    return USB_EP_IO(ep, read, buffer, size, complete);
}

/* Configure and endponint and perform a write operation */
static stm32_UsbIoStatus
__usb_ep_write(int ep, const void *buffer, ssize_t size, void (*complete)(int))
{
    if (UNLIKELY((ep >= EP_MAX_NUM) || !(ep & 0x01)))
    {
        LOG_ERR("%s: invalid EP number %d\n", __func__, ep);
        ASSERT(0);
        return STALLED;
    }
    if (UNLIKELY((size_t)buffer & 0x03))
    {
        LOG_ERR("%s: unaligned buffer @ %p\n", __func__, buffer);
        ASSERT(0);
        return STALLED;
    }
    return USB_EP_IO(ep, write, buffer, size, complete);
}

static void usb_ep_low_level_config(int ep, uint16_t offset, uint16_t size)
{
    stm32_UsbEp *epc = &ep_cnfg[ep];

    /* IN EP */
    if (ep & 0x01)
    {
        /* Disable EP */
        ep_ctrl_set_stat_tx(epc->hw, EP_DISABLED);
        /* Clear Tx toggle */
        ep_ctrl_set_dtog_tx(epc->hw, 0);
        /* Clear Correct Transfer for transmission flag */
        ep_ctrl_clr_ctr_tx(epc->hw);

        /* Update EP description table */
        EP_DTB_WRITE(ep >> 1, ADDR_TX_OFFSET, offset);
        EP_DTB_WRITE(ep >> 1, COUNT_TX_OFFSET, 0);
    }
    /* OUT EP */
    else
    {
        uint16_t rx_count = 0;

        /* Disable EP */
        ep_ctrl_set_stat_rx(epc->hw, EP_DISABLED);
        /* Clear Rx toggle */
        ep_ctrl_set_dtog_rx(epc->hw, 0);
        /* Clear Correct Transfer for reception flag */
        ep_ctrl_clr_ctr_rx(epc->hw);
        /* Descriptor block size field */
        rx_count |= (size > 62) << 15;
        /* Descriptor number of blocks field */
        rx_count |= (((size > 62) ?  (size >> 5) - 1 : size >> 1) &
                0x1f) << 10;
        /* Update EP description table */
        EP_DTB_WRITE(ep >> 1, ADDR_RX_OFFSET, offset);
        EP_DTB_WRITE(ep >> 1, COUNT_RX_OFFSET, rx_count);
    }
}

/* Enable/Disable an endpoint */
static int usb_ep_configure(const UsbEndpointDesc *epd, bool enable)
{
    int EP;
    stm32_UsbEp *ep_hw;
    reg32_t *hw;
    uint16_t Offset;
    uint32_t size;

    EP = usb_ep_logical_to_hw(epd->bEndpointAddress);
    ep_hw = &ep_cnfg[EP];

    if (enable)
    {
        /*
         * Allocate packet memory for EP buffer/s calculate actual size
         * only for the OUT EPs.
         */
        size = epd->wMaxPacketSize;
        if (!usb_alloc_buffer(&Offset, &size, EP))
            return -USB_MEMORY_FULL;

        /* Set EP status */
        ep_hw->status  = NOT_READY;
        /* Init EP flags */
        ep_hw->flags = 0;

        /* Set endpoint type */
        ep_hw->type = usb_endpointType(epd);
        /* Init EP max packet size */
        ep_hw->max_size = epd->wMaxPacketSize;

        if (EP & 0x01)
            ep_hw->avail_data = 1;
        else
            ep_hw->avail_data = 0;
        hw = (reg32_t *)&usb->EP0R;
        hw += EP >> 1;

        /* Set Ep Address */
        ep_ctrl_set_ea(hw, EP >> 1);
        ep_hw->hw = hw;
        LOG_INFO("%s: EP%d-%s configured\n",
                __func__, EP >> 1, EP & 1 ? "IN" : "OUT");

        /* Low-level endpoint configuration */
        usb_ep_low_level_config(EP, Offset, size);

        /* Set EP Kind & enable */
        switch (ep_hw->type)
        {
        case USB_ENDPOINT_XFER_CONTROL:
            LOG_INFO("EP%d: CONTROL %s\n", EP >> 1,
                    EP & 1 ? "IN" : "OUT");
            ep_ctrl_set_ep_type(hw, EP_CTRL);
            ep_ctrl_set_ep_kind(hw, 0);
            break;
        case USB_ENDPOINT_XFER_INT:
            LOG_INFO("EP%d: INTERRUPT %s\n", EP >> 1,
                    EP & 1 ? "IN" : "OUT");
            ep_ctrl_set_ep_type(hw, EP_INTERRUPT);
            ep_ctrl_set_ep_kind(hw, 0);
            break;
        case USB_ENDPOINT_XFER_BULK:
            LOG_INFO("EP%d: BULK %s\n", EP >> 1,
                    EP & 1 ? "IN" : "OUT");
            ep_ctrl_set_ep_type(hw, EP_BULK);
            ep_ctrl_set_ep_kind(hw, 0);
            break;
        case USB_ENDPOINT_XFER_ISOC:
            LOG_ERR("EP%d: ISOCHRONOUS %s: not supported\n",
                    EP >> 1,
                    EP & 1 ? "IN" : "OUT");
            /* Fallback to default */
        default:
            ASSERT(0);
            return -USB_NODEV_ERROR;
        }
        if (EP & 0x01)
        {
            /* Enable EP */
            ep_ctrl_set_stat_tx(hw, EP_NAK);
            /* Clear Correct Transfer for transmission flag */
            ep_ctrl_clr_ctr_tx(hw);
        }
        else
        {
            /* Enable EP */
            ep_ctrl_set_stat_rx(hw, EP_VALID);
        }
    }
    else if (ep_cnfg[EP].hw)
    {
        hw = (reg32_t *)&usb->EP0R;
        hw += EP >> 1;

        /* IN EP */
        if (EP & 0x01)
        {
            /* Disable IN EP */
            ep_ctrl_set_stat_tx(hw, EP_DISABLED);
            /* Clear Correct Transfer for reception flag */
            ep_ctrl_clr_ctr_tx(hw);
        }
        /* OUT EP */
        else
        {
            /* Disable OUT EP */
            ep_ctrl_set_stat_rx(hw, EP_DISABLED);
            /* Clear Correct Transfer for reception flag */
            ep_ctrl_clr_ctr_rx(hw);
        }
        /* Release buffer */
        usb_free_buffer(EP);
        ep_cnfg[EP].hw = NULL;
    }
    return 0;
}

/* Get EP stall/unstall */
static int usb_ep_get_stall(int EP, bool *pStall)
{
    if (ep_cnfg[EP].hw == NULL)
        return -USB_NODEV_ERROR;

    *pStall = (EP & 0x01) ?
        (ep_ctrl_get_stat_tx(ep_cnfg[EP].hw) == EP_STALL):  /* IN EP  */
        (ep_ctrl_get_stat_rx(ep_cnfg[EP].hw) == EP_STALL);  /* OUT EP */

    return USB_OK;
}

/* Set EP stall/unstall */
static int usb_ep_set_stall(int EP, bool Stall)
{
    if (ep_cnfg[EP].hw == NULL)
        return -USB_NODEV_ERROR;

    if (Stall)
    {
        ep_cnfg[EP].status = STALLED;
        if (EP & 0x01)
        {
            /* IN EP */
            ep_ctrl_set_stat_tx(ep_cnfg[EP].hw, EP_STALL);
            ep_cnfg[EP].avail_data = 1;
        }
        else
        {
            /* OUT EP */
            ep_ctrl_set_stat_rx(ep_cnfg[EP].hw, EP_STALL);
            ep_cnfg[EP].avail_data = 0;
        }
    }
    else
    {
        ep_cnfg[EP].status = NOT_READY;
        if(EP & 0x01)
        {
            /* IN EP */
            ep_cnfg[EP].avail_data = 1;
            /* reset Data Toggle bit */
            ep_ctrl_set_dtog_tx(ep_cnfg[EP].hw, 0);
            ep_ctrl_set_stat_tx(ep_cnfg[EP].hw, EP_NAK);
        }
        else
        {
            /* OUT EP */
            ep_cnfg[EP].avail_data = 0;
            /* reset Data Toggle bit */
            ep_ctrl_set_dtog_rx(ep_cnfg[EP].hw, 0);
            ep_ctrl_set_stat_rx(ep_cnfg[EP].hw, EP_VALID);
        }
    }
    return USB_OK;
}

/* Stall both directions of the control EP */
static void usb_ep_set_stall_ctrl(void)
{
    ep_cnfg[CTRL_ENP_IN].avail_data = 1;
    ep_cnfg[CTRL_ENP_IN].status = STALLED;
    ep_cnfg[CTRL_ENP_OUT].avail_data = 0;
    ep_cnfg[CTRL_ENP_OUT].status = STALLED;

    usb_ep_set_stall(CTRL_ENP_IN, true);
    usb_ep_set_stall(CTRL_ENP_OUT, true);
}

/*
 * Find the position of an interface descriptor inside the configuration
 * descriptor.
 */
static int usb_find_interface(uint32_t num, uint32_t alt)
{
    const UsbInterfaceDesc *id;
    int i;

    for (i = 0; ; i++)
    {
        /* TODO: support more than one configuration per device */
        id = (const UsbInterfaceDesc *)usb_dev->config[i];
        if (id == NULL)
            break;
        if (id->bDescriptorType != USB_DT_INTERFACE)
            continue;
        if ((id->bInterfaceNumber == num) &&
                (id->bAlternateSetting == alt))
            return i;
    }
    return -USB_NODEV_ERROR;
}

/*
 * Configure/deconfigure EPs of a certain interface.
 */
static void
usb_configure_ep_interface(unsigned int num, unsigned int alt, bool enable)
{
    const UsbEndpointDesc *epd;
    int i, start;

    /*
     * Find the position of the interface descriptor (inside the
     * configuration descriptor).
     */
    start = usb_find_interface(num, alt);
    if (start < 0)
    {
        LOG_ERR("%s: interface (%u,%u) not found\n",
            __func__, num, alt);
        return;
    }
    /*
     * Cycle over endpoint descriptors.
     *
     * NOTE: the first endpoint descriptor is placed next to the interface
     * descriptor, so we need to add +1 to the position of the interface
     * descriptor to find it.
     */
    for (i = start + 1; ; i++)
    {
        epd = (const UsbEndpointDesc *)usb_dev->config[i];
        if ((epd == NULL) || (epd->bDescriptorType == USB_DT_INTERFACE))
            break;
        if (epd->bDescriptorType != USB_DT_ENDPOINT)
            continue;
        if (UNLIKELY(usb_ep_configure(epd, enable) < 0))
        {
            LOG_ERR("%s: out of memory, can't initialize EP\n",
                __func__);
            return;
        }
    }
}

/* Set device state */
static void usb_set_device_state(int state)
{
    unsigned int i;

    LOG_INFO("%s: new state %d\n", __func__, state);

    if (udc.state == USB_STATE_CONFIGURED)
    {
        /* Deconfigure device */
        for (i = 0; i < udc.interfaces; ++i)
            usb_configure_ep_interface(i,
                udc.alt[i], false);
    }
    switch (state)
    {
    case USB_STATE_ATTACHED:
    case USB_STATE_POWERED:
    case USB_STATE_DEFAULT:
        usb_set_address(0);
        usb_dev->configured = false;
        udc.address = udc.cfg_id = 0;
        break;
    case USB_STATE_ADDRESS:
        udc.cfg_id = 0;
        break;
    case USB_STATE_CONFIGURED:
        /* Configure device */
        for (i = 0; i < udc.interfaces; ++i)
            usb_configure_ep_interface(i,
                udc.alt[i], true);
        break;
    default:
        /* Unknown state: disconnected or connection in progress */
        usb_dev->configured = false;
        udc.address = 0;
        udc.cfg_id = 0;
        break;
    }
    udc.state = state;
}

/* Setup packet: set address status phase end handler */
static void usb_add_status_handler_end(UNUSED_ARG(int, EP))
{
    uint16_t w_value;

    w_value = usb_le16_to_cpu(setup_packet.wValue);
    udc.address = w_value & 0xff;
    usb_set_address(udc.address);

    if (udc.address)
        usb_set_device_state(USB_STATE_ADDRESS);
    else
        usb_set_device_state(USB_STATE_DEFAULT);

    __usb_ep_write(CTRL_ENP_IN, NULL, -1, NULL);
    __usb_ep_read(CTRL_ENP_OUT, NULL, -1, NULL);
}

/* Prepare status phase */
static void usb_status_phase(bool in)
{
    if (in)
        __usb_ep_write(CTRL_ENP_IN, NULL, 0, NULL);
}

/* Setup packet: status phase end handler */
static void usb_status_handler_end(UNUSED_ARG(int, EP))
{
    __usb_ep_write(CTRL_ENP_IN, NULL, -1, NULL);
    __usb_ep_read(CTRL_ENP_OUT, NULL, -1, NULL);
}

/* Address status handler */
static void usb_status_handler(UNUSED_ARG(int, EP))
{
    if (setup_packet.mRequestType & USB_DIR_IN)
    {
        usb_status_phase(false);
        ep_cnfg[CTRL_ENP_OUT].complete = usb_status_handler_end;
    }
    else
    {
        usb_status_phase(true);
        ep_cnfg[CTRL_ENP_IN].complete =
            (setup_packet.bRequest == USB_REQ_SET_ADDRESS) ?
                usb_add_status_handler_end :
                usb_status_handler_end;
    }
}

static void usb_endpointRead_complete(int ep)
{
    if (UNLIKELY(ep >= EP_MAX_NUM))
    {
        ASSERT(0);
        return;
    }
    ASSERT(!(ep & 0x01));

    event_do(&usb_event_done[ep >> 1]);
    rx_size = ep_cnfg[ep].size;
}

ssize_t usb_endpointReadTimeout(int ep, void *buffer, ssize_t size,
                ticks_t timeout)
{
    int ep_num = usb_ep_logical_to_hw(ep);
    ssize_t max_size = sizeof(ep_buffer[ep_num]);

    /* Non-blocking read for EP0 */
    if (in_atomic && (ep_num == CTRL_ENP_OUT))
    {
        size = usb_size(size, usb_le16_to_cpu(setup_packet.wLength));
        if (UNLIKELY(size > max_size))
        {
            LOG_ERR("%s: ep_buffer exceeded, try to enlarge CONFIG_USB_BUFSIZE\n",
                    __func__);
            ASSERT(0);
            return -USB_BUF_OVERFLOW;
        }
        if (!size)
            usb_status_handler(ep_num);
        else
        {
            __usb_ep_read(ep_num, ep_buffer[ep_num], size,
                    usb_status_handler);
            memcpy(buffer, ep_buffer[ep_num], size);
        }
        return size;
    }
    if (UNLIKELY(!size))
        return 0;
    size = MIN(size, max_size);
    event_initGeneric(&usb_event_done[ep_num >> 1]);
    rx_size = 0;

    /* Blocking read */
    __usb_ep_read(ep_num, ep_buffer[ep_num], size,
                usb_endpointRead_complete);
    if (timeout < 0)
        event_wait(&usb_event_done[ep_num >> 1]);
    else
        if (!event_waitTimeout(&usb_event_done[ep_num >> 1], timeout))
            return 0;
    memcpy(buffer, ep_buffer[ep_num], rx_size);

    return rx_size;
}

static void usb_endpointWrite_complete(int ep)
{
    if (UNLIKELY(ep >= EP_MAX_NUM))
    {
        ASSERT(0);
        return;
    }
    ASSERT(ep & 0x01);

    event_do(&usb_event_done[ep >> 1]);
    tx_size = ep_cnfg[ep].size;
}

ssize_t usb_endpointWriteTimeout(int ep, const void *buffer, ssize_t size,
                ticks_t timeout)
{
    int ep_num = usb_ep_logical_to_hw(ep);
    ssize_t max_size = sizeof(ep_buffer[ep_num]);

    /* Non-blocking write for EP0 */
    if (in_atomic && (ep_num == CTRL_ENP_IN))
    {
        size = usb_size(size, usb_le16_to_cpu(setup_packet.wLength));
        if (UNLIKELY(size > max_size))
        {
            LOG_ERR("%s: ep_buffer exceeded, try to enlarge CONFIG_USB_BUFSIZE\n",
                    __func__);
            ASSERT(0);
            return -USB_BUF_OVERFLOW;
        }
        if (!size)
            usb_status_handler(ep_num);
        else
        {
            memcpy(ep_buffer[ep_num], buffer, size);
            __usb_ep_write(ep_num, ep_buffer[ep_num], size,
                    usb_status_handler);
        }
        return size;
    }
    if (UNLIKELY(!size))
        return 0;
    size = MIN(size, max_size);
    event_initGeneric(&usb_event_done[ep_num >> 1]);
    tx_size = 0;

    /* Blocking write */
    memcpy(ep_buffer[ep_num], buffer, size);
    __usb_ep_write(ep_num, ep_buffer[ep_num], size,
                usb_endpointWrite_complete);
    if (timeout < 0)
        event_wait(&usb_event_done[ep_num >> 1]);
    else
        if (!event_waitTimeout(&usb_event_done[ep_num >> 1], timeout))
            return 0;

    return tx_size;
}

/* Global variable to handle the following non-blocking I/O operations */
static uint32_t InData;

/* Get device status */
static int usb_send_device_status(uint16_t index)
{
    if (index)
        return -USB_NODEV_ERROR;

    InData = ((uint32_t)udc.feature) & 0xff;
    __usb_ep_write(CTRL_ENP_IN,
            (uint8_t *)&InData, sizeof(uint16_t),
            usb_status_handler);
    return 0;
}

/* Get interface status */
static int usb_send_interface_status(UNUSED_ARG(uint16_t, index))
{
    InData = 0;
    __usb_ep_write(CTRL_ENP_IN,
            (uint8_t *)&InData, sizeof(uint16_t),
            usb_status_handler);
    return 0;
}

/* Get endpoint status */
static int usb_send_ep_status(uint16_t index)
{
    if ((index & 0x7F) > 16)
        return -USB_NODEV_ERROR;

    InData = 0;
    usb_ep_get_stall(usb_ep_logical_to_hw(index), (bool *)&InData);
    __usb_ep_write(CTRL_ENP_IN,
            (uint8_t *)&InData, sizeof(uint16_t),
            usb_status_handler);
    return 0;
}

/* USB setup packet: GET_STATUS request handler */
static void usb_get_status_handler(void)
{
    uint16_t w_value = usb_le16_to_cpu(setup_packet.wValue);
    uint16_t w_index = usb_le16_to_cpu(setup_packet.wIndex);
    uint16_t w_length = usb_le16_to_cpu(setup_packet.wLength);

    /* GET_STATUS sanity checks */
    if (udc.state < USB_STATE_ADDRESS)
    {
        LOG_WARN("%s: bad GET_STATUS request (State=%02x)\n",
                __func__, udc.state);
        ep_cnfg[CTRL_ENP_OUT].status = STALLED;
        return;
    }
    if (w_length != 2)
    {
        LOG_WARN("%s: bad GET_STATUS request (wLength.Word=%02x)\n",
                __func__, w_length);
        ep_cnfg[CTRL_ENP_OUT].status = STALLED;
        return;
    }
    if (!(setup_packet.mRequestType & USB_DIR_IN))
    {
        LOG_WARN("%s: bad GET_STATUS request (mRequestType=%02x)\n",
                __func__, setup_packet.mRequestType);
        ep_cnfg[CTRL_ENP_OUT].status = STALLED;
        return;
    }
    if (w_value)
    {
        LOG_WARN("%s: bad GET_STATUS request (wValue=%02x)\n",
                __func__, w_value);
        ep_cnfg[CTRL_ENP_OUT].status = STALLED;
        return;
    }

    /* Process GET_STATUS request */
    switch (setup_packet.mRequestType & USB_RECIP_MASK)
    {
    case USB_RECIP_DEVICE:
        if (usb_send_device_status(w_index) < 0)
        {
            LOG_WARN("%s: GET_STATUS: invalid UsbRecipientDevice\n",
                    __func__);
            ep_cnfg[CTRL_ENP_OUT].status = STALLED;
            return;
        }
        LOG_INFO("%s: GET_STATUS: mRequestType=%02x (UsbRecipientDevice)\n",
                __func__, setup_packet.mRequestType);
        break;
    case USB_RECIP_INTERFACE:
        if (usb_send_interface_status(w_index) < 0)
        {
            LOG_WARN("%s: GET_STATUS: invalid UsbRecipientInterface\n",
                    __func__);
            ep_cnfg[CTRL_ENP_OUT].status = STALLED;
            return;
        }
        LOG_INFO("%s: GET_STATUS: mRequestType=%02x (UsbRecipientInterface)\n",
                __func__, setup_packet.mRequestType);
        break;
    case USB_RECIP_ENDPOINT:
        if (usb_send_ep_status(w_index) < 0)
        {
            LOG_WARN("%s: GET_STATUS: invalid UsbRecipientEndpoint\n",
                    __func__);
            ep_cnfg[CTRL_ENP_OUT].status = STALLED;
            return;
        }
        LOG_INFO("%s: GET_STATUS: mRequestType=%02x (UsbRecipientEndpoint)\n",
                __func__, setup_packet.mRequestType);
        break;
    default:
        LOG_WARN("%s: GET_STATUS: invalid UsbRecipientEndpoint\n",
                __func__);
        ep_cnfg[CTRL_ENP_OUT].status = STALLED;
        break;
    }
}

static int usb_get_device_descriptor(int id)
{
    if (id)
        return -USB_NODEV_ERROR;

    usb_dev->device->bMaxPacketSize0 = USB_EP0_MAX_SIZE;
    __usb_ep_write(CTRL_ENP_IN, (const uint8_t *)usb_dev->device,
            usb_size(usb_dev->device->bLength,
                usb_le16_to_cpu(setup_packet.wLength)),
            usb_status_handler);
    return 0;
}

/*
 * TODO: refactor this part to remove this temporary buffer.
 *
 * It would be better to define all the USB descriptors in the right order and
 * send them as a contiguous buffer directly from the flash / rodata memory.
 */
#define USB_BUFSIZE (128)
static uint8_t usb_cfg_buffer[USB_BUFSIZE];
STATIC_ASSERT(USB_BUFSIZE < (1 << (sizeof(uint16_t) * 8)));

static int usb_get_configuration_descriptor(int id)
{
    const UsbConfigDesc **config =
            (const UsbConfigDesc **)usb_dev->config;
    uint8_t *p = usb_cfg_buffer;
    int i;

    /* TODO: support more than one configuration per device */
    if (UNLIKELY(id > 0))
        return -USB_NODEV_ERROR;

    for (i = 0; config[i]; i++)
    {
        memcpy(p, config[i], config[i]->bLength);
        p += config[i]->bLength;

        if (UNLIKELY((p - usb_cfg_buffer) > USB_BUFSIZE))
        {
            ASSERT(0);
            return -USB_BUF_OVERFLOW;
        }
    }
    ((UsbConfigDesc *)usb_cfg_buffer)->wTotalLength =
            usb_cpu_to_le16((uint16_t)(p - usb_cfg_buffer));
    __usb_ep_write(CTRL_ENP_IN,
            usb_cfg_buffer,
            usb_size(p - usb_cfg_buffer,
                usb_le16_to_cpu(setup_packet.wLength)),
            usb_status_handler);
    return 0;
}

static int usb_get_string_descriptor(unsigned int id)
{
    const UsbStringDesc *lang_str;
    unsigned int lang_id, str_id;
    uint16_t w_index_lo = usb_le16_to_cpu(setup_packet.wIndex) & 0x00ff;
    uint16_t w_index_hi = (usb_le16_to_cpu(setup_packet.wIndex) &
                        0xff00) >> 8;

    ASSERT(usb_dev->strings != NULL);
    ASSERT(usb_dev->strings[0] != NULL);

    lang_str = usb_dev->strings[0];
    if (id)
    {
        /* Find Language index */
        for (lang_id = 0; ; lang_id++)
        {
            const UsbStringDesc *str =
                        usb_dev->strings[lang_id];
            if (UNLIKELY(str == NULL))
                return -USB_NODEV_ERROR;
            if ((str->data[0] == w_index_lo) &&
                    (str->data[1] == w_index_hi))
                break;
        }
        /* Check buffer overflow to find string index */
        for (str_id = 0; str_id < id; str_id++)
        {
            lang_str = usb_dev->strings[lang_id + 1 + str_id];
            if (lang_str == NULL)
                return -USB_NODEV_ERROR;
        }
    }
    __usb_ep_write(CTRL_ENP_IN,
            lang_str,
            usb_size(lang_str->bLength,
                usb_le16_to_cpu(setup_packet.wLength)),
            usb_status_handler);
    return 0;
}

static void usb_get_descriptor(void)
{
    uint16_t w_value_lo = usb_le16_to_cpu(setup_packet.wValue) & 0x00ff;
    uint16_t w_value_hi = (usb_le16_to_cpu(setup_packet.wValue) & 0xff00) >> 8;

    if (udc.state < USB_STATE_DEFAULT)
    {
        ep_cnfg[CTRL_ENP_OUT].status = STALLED;
        return;
    }
    switch (w_value_hi)
    {
    case USB_DT_DEVICE:
        LOG_INFO("%s: GET_DEVICE_DESCRIPTOR: id=%d, state=%d\n",
                __func__,
                w_value_lo,
                udc.state);
        if (usb_get_device_descriptor(w_value_lo) < 0)
            ep_cnfg[CTRL_ENP_OUT].status = STALLED;
        break;
    case USB_DT_CONFIG:
        LOG_INFO("%s: GET_CONFIG_DESCRIPTOR: id=%d, state=%d\n",
                __func__, w_value_lo, udc.state);
        if (usb_get_configuration_descriptor(w_value_lo) < 0)
            ep_cnfg[CTRL_ENP_OUT].status = STALLED;
        break;
    case USB_DT_STRING:
        LOG_INFO("%s: GET_STRING_DESCRIPTOR: id=%d, state=%d\n",
                __func__, w_value_lo, udc.state);
        if (usb_get_string_descriptor(w_value_lo) < 0)
            ep_cnfg[CTRL_ENP_OUT].status = STALLED;
        break;
    default:
        LOG_WARN("%s: GET_UNKNOWN_DESCRIPTOR: id=%d, state=%d\n",
                __func__, w_value_lo, udc.state);
        ep_cnfg[CTRL_ENP_OUT].status = STALLED;
        break;
    }
}

/* USB setup packet: class/vendor request handler */
static void usb_event_handler(UsbDevice *dev)
{
    /*
     * TODO: get the appropriate usb_dev in function of the endpoint
     * address.
     */
    if (dev->event_cb)
        dev->event_cb(&setup_packet);
}

/* USB setup packet: GET_DESCRIPTOR handler */
static void usb_get_descriptor_handler(void)
{
    LOG_INFO("%s: GET_DESCRIPTOR: RECIP = %d\n",
            __func__,
            setup_packet.mRequestType & USB_RECIP_MASK);
    if ((setup_packet.mRequestType & USB_RECIP_MASK) ==
            USB_RECIP_DEVICE)
        usb_get_descriptor();
    else
        usb_event_handler(usb_dev);
}

/* USB setup packet: SET_ADDRESS handler */
static void usb_set_address_handler(void)
{
    uint16_t w_value = usb_le16_to_cpu(setup_packet.wValue);
    uint16_t w_index = usb_le16_to_cpu(setup_packet.wIndex);
    uint16_t w_length = usb_le16_to_cpu(setup_packet.wLength);

    LOG_INFO("%s: SET_ADDRESS: %d\n",
            __func__, usb_le16_to_cpu(setup_packet.wValue));
    if ((udc.state >= USB_STATE_DEFAULT) &&
            ((setup_packet.mRequestType & USB_RECIP_MASK) ==
                    USB_RECIP_DEVICE) &&
            (w_index == 0) && (w_length == 0) && (w_value < 128))
        usb_status_handler(CTRL_ENP_IN);
    else
        ep_cnfg[CTRL_ENP_OUT].status = STALLED;
}

/* USB setup packet: GET_CONFIGURATION handler */
static void usb_get_config_handler(void)
{
    uint16_t w_value = usb_le16_to_cpu(setup_packet.wValue);
    uint16_t w_index = usb_le16_to_cpu(setup_packet.wIndex);

    LOG_INFO("%s: GET_CONFIGURATION\n", __func__);
    if ((udc.state >= USB_STATE_ADDRESS) &&
            (w_value == 0) && (w_index == 0) && (w_value == 1))
    {
        InData = udc.cfg_id;
        __usb_ep_write(CTRL_ENP_IN, (uint8_t *)&InData, 1, usb_status_handler);
    }
    else
        ep_cnfg[CTRL_ENP_OUT].status = STALLED;
}

static const UsbConfigDesc *usb_find_configuration(int num)
{
    const UsbConfigDesc *cfg;
    int i;

    for (i = 0; ; i++)
    {
        cfg = (const UsbConfigDesc *)usb_dev->config[i];
        if (cfg == NULL)
            break;
        if (cfg->bDescriptorType != USB_DT_CONFIG)
            continue;
        if (cfg->bConfigurationValue == num)
            return cfg;
    }
    return NULL;
}

static int usb_set_config_state(uint32_t conf)
{
    const UsbConfigDesc *pCnfg;
    unsigned int i;

    if (conf)
    {
        /* Find configuration descriptor */
        pCnfg = usb_find_configuration(conf);
        if (pCnfg == NULL)
            return -USB_NODEV_ERROR;

        /* Reset current configuration */
        usb_set_device_state(USB_STATE_ADDRESS);
        usb_dev->configured = false;
        udc.cfg = pCnfg;

        /* Set Interface and Alternative Setting */
        udc.cfg_id = conf;
        /* Set self-powered state */
        if (pCnfg->bmAttributes & USB_CONFIG_ATT_SELFPOWER)
            udc.feature |= STM32_UDC_FEATURE_SELFPOWERED;

        /* Configure all existing interfaces to alternative setting 0 */
        ASSERT(pCnfg->bNumInterfaces <= USB_MAX_INTERFACE);
        udc.interfaces = pCnfg->bNumInterfaces;
        for (i = 0; i < udc.interfaces; i++)
            udc.alt[i] = 0;
        usb_set_device_state(USB_STATE_CONFIGURED);
        usb_dev->configured = true;
        event_do(&usb_event_done[0]);
        LOG_INFO("%s: device configured\n", __func__);
    }
    else
    {
        usb_dev->configured = false;
        usb_set_device_state(USB_STATE_ADDRESS);
    }
    return 0;
}

/* USB setup packet: SET_CONFIGURATION handler */
static void usb_set_config_handler(void)
{
    uint16_t w_value = usb_le16_to_cpu(setup_packet.wValue);
    uint16_t w_index = usb_le16_to_cpu(setup_packet.wIndex);
    uint16_t w_length = usb_le16_to_cpu(setup_packet.wLength);

    LOG_INFO("%s: SET_CONFIGURATION: %d\n",
            __func__, w_value);
    if ((udc.state >= USB_STATE_ADDRESS) &&
            (w_index == 0) && (w_length == 0) &&
            (usb_set_config_state(w_value & 0xff) == 0))
        usb_status_handler(CTRL_ENP_OUT);
    else
        ep_cnfg[CTRL_ENP_OUT].status = STALLED;
}

/* USB setup packet: standard request handler */
static void usb_standard_request_handler(void)
{
    switch (setup_packet.bRequest)
    {
    case USB_REQ_GET_STATUS:
        usb_get_status_handler();
        break;
    case USB_REQ_CLEAR_FEATURE:
        LOG_INFO("%s: bRequest=%d (CLEAR_FEATURE)\n",
                __func__, setup_packet.bRequest);
        break;
    case USB_REQ_SET_FEATURE:
        LOG_INFO("%s: bRequest=%d (SET_FEATURE)\n",
                __func__, setup_packet.bRequest);
        break;
    case USB_REQ_SET_ADDRESS:
        usb_set_address_handler();
        break;
    case USB_REQ_GET_DESCRIPTOR:
        usb_get_descriptor_handler();
        break;
    case USB_REQ_SET_DESCRIPTOR:
        LOG_INFO("%s: bRequest=%d (SET_DESCRIPTOR)\n",
                __func__, setup_packet.bRequest);
        break;
    case USB_REQ_GET_CONFIGURATION:
        usb_get_config_handler();
        break;
    case USB_REQ_SET_CONFIGURATION:
        usb_set_config_handler();
        break;
    case USB_REQ_GET_INTERFACE:
        LOG_INFO("%s: bRequest=%d (GET_INTERFACE)\n",
                __func__, setup_packet.bRequest);
        break;
    case USB_REQ_SET_INTERFACE:
        LOG_INFO("%s: bRequest=%d (SET_INTERFACE)\n",
                __func__, setup_packet.bRequest);
        break;
    case USB_REQ_SYNCH_FRAME:
        LOG_INFO("%s: bRequest=%d (SYNCH_FRAME)\n",
                __func__, setup_packet.bRequest);
        break;
    default:
        LOG_WARN("%s: bRequest=%d (Unknown)\n",
                __func__, setup_packet.bRequest);
        ep_cnfg[CTRL_ENP_OUT].status = STALLED;
        break;
    }
}

/* USB setup packet handler */
static void usb_setup_handler(void)
{
    switch (setup_packet.mRequestType & USB_TYPE_MASK)
    {
    /* Standard */
    case USB_TYPE_STANDARD:
        LOG_INFO("%s: bmRequestType=%02x (Standard)\n",
                __func__, setup_packet.mRequestType);
        usb_standard_request_handler();
        break;
    /* Class */
    case USB_TYPE_CLASS:
        LOG_INFO("%s: bmRequestType=%02x (Class)\n",
                __func__, setup_packet.mRequestType);
        usb_event_handler(usb_dev);
        break;
    /* Vendor */
    case USB_TYPE_VENDOR:
        LOG_INFO("%s: bmRequestType=%02x (Vendor)\n",
                __func__, setup_packet.mRequestType);
        usb_event_handler(usb_dev);
        break;
    case USB_TYPE_RESERVED:
        LOG_INFO("%s: bmRequestType=%02x (Reserved)\n",
                __func__, setup_packet.mRequestType);
        break;
    /* Other */
    default:
        LOG_WARN("%s: bmRequestType=%02x (Unknown)\n",
                __func__, setup_packet.mRequestType);
        ep_cnfg[CTRL_ENP_OUT].status = STALLED;
        break;
    }
}

/* USB: low-level hardware initialization */
static void usb_hw_reset(void)
{
    unsigned int i;
    int ret;

    /* Initialize endpoint descriptors */
    for (i = 0; i < countof(ep_cnfg); i++)
        ep_cnfg[i].hw = NULL;

    /* Initialize USB memory */
    for (i = 0; i < countof(memory_buffer); i++)
        memory_buffer[i].Size = 0;
    usb->BTABLE = USB_BDT_OFFSET;
    mem_use = NULL;

    /* Endpoint initialization */
    ret = usb_ep_configure(&USB_CtrlEpDescr0, true);
    if (UNLIKELY(ret < 0))
    {
        LOG_WARN("%s: out of memory, cannot initialize EP0\n",
                __func__);
        return;
    }
    ret = usb_ep_configure(&USB_CtrlEpDescr1, true);
    if (UNLIKELY(ret < 0))
    {
        LOG_WARN("%s: out of memory, cannot initialize EP1\n",
                __func__);
        return;
    }

    /* Set default address */
    usb_set_address(0);

    /* Enable all the device interrupts */
    usb->CNTR = bmCTRM | bmRESETM | bmSOFM | bmERRM | bmPMAOVRM |
            bmSUSPM | bmWKUPM;
}

/* Handle a correct transfer under ISR */
static void usb_isr_correct_transfer(stm32_usb_irq_status_t interrupt)
{
    int EP;
    reg32_t *pReg = (reg32_t *)&usb->EP0R;

    /* Find corresponding EP */
    pReg += interrupt.EP_ID;
    EP = (int)(((*pReg & 0x0f) << 1) + (interrupt.DIR ? 0 : 1));
    ep_cnfg[EP].avail_data = 1;

    ASSERT(ep_cnfg[EP].hw);
    /* IN EP */
    if (EP & 0x01)
        ep_ctrl_clr_ctr_tx(ep_cnfg[EP].hw);
    else
        ep_ctrl_clr_ctr_rx(ep_cnfg[EP].hw);
    if (EP == CTRL_ENP_OUT)
    {
        /* Determinate type of packet (only for control EP) */
        bool SetupPacket = ep_ctrl_get_setup(ep_cnfg[CTRL_ENP_OUT].hw);

        if (SetupPacket)
        {
            ep_cnfg[CTRL_ENP_IN].avail_data = 1;
            /* init IO to receive Setup packet */
            __usb_ep_write(CTRL_ENP_IN, NULL, -1, NULL);
            __usb_ep_read(CTRL_ENP_OUT, &setup_packet,
                    sizeof(setup_packet), NULL);

            /* reset EP IO ctrl */
            if (setup_packet.mRequestType & USB_DIR_IN)
                usb_status_handler(CTRL_ENP_OUT);
            usb_setup_handler();
            if (ep_cnfg[CTRL_ENP_OUT].status == STALLED)
                usb_ep_set_stall_ctrl();
        }
        else
        {
            if (ep_cnfg[CTRL_ENP_OUT].complete &&
                    setup_packet.mRequestType & USB_DIR_IN)
                ep_cnfg[CTRL_ENP_OUT].complete(CTRL_ENP_OUT);
            else
                __usb_ep_io(EP);
        }
    }
    else if (EP == CTRL_ENP_IN)
    {
        if (ep_cnfg[CTRL_ENP_IN].complete &&
                !(setup_packet.mRequestType & USB_DIR_IN))
            ep_cnfg[CTRL_ENP_IN].complete(CTRL_ENP_IN);
        else
            __usb_ep_io(EP);

    }
    else
        __usb_ep_io(EP);
}

/* USB: interrupt service routine */
static void usb_isr(void)
{
    stm32_usb_irq_status_t interrupt;

    /* Get masked interrupt flags */
    interrupt.status = usb->ISTR;
    interrupt.status &= usb->CNTR | 0x1f;

    /* Set the context as atomic */
    in_atomic = true;

    if (interrupt.PMAOVR)
    {
        LOG_WARN("%s: DMA overrun / underrun\n", __func__);
        usb->ISTR = ~bmPMAOVRM;
    }
    if (interrupt.ERR)
    {
        LOG_WARN("%s: engine error\n", __func__);
        usb->ISTR = ~bmERRM;
    }
    if (interrupt.RESET)
    {
        LOG_INFO("%s: device reset\n", __func__);
        usb->ISTR = ~bmRESETM;
        usb_hw_reset();
        usb_set_device_state(USB_STATE_DEFAULT);
    }
    if (interrupt.SOF)
    {
#if 0
        /*
         * XXX: disable logging of frame interrupts (too much noise!)
         */
        uint16_t frame_nr = usb->FNR & 0x0fff;
        LOG_INFO("%s: frame %#x\n", __func__, frame_nr);
#endif
        usb->ISTR = ~bmSOFM;
    }
    if (interrupt.WKUP)
    {
        LOG_INFO("%s: wake-up\n", __func__);
        usb->ISTR = ~(bmSUSPM | bmWKUPM);
        usb_resume();
    }
    if (interrupt.SUSP)
    {
        LOG_INFO("%s: suspend\n", __func__);
        usb_suspend();
        usb->ISTR = ~(bmSUSPM | bmWKUPM);
    }
    if (interrupt.ESOF)
    {
        LOG_INFO("%s: expected frame\n", __func__);
        usb->ISTR = ~bmESOFM;
    }
    if (interrupt.CTR)
    {
        usb_isr_correct_transfer(interrupt);
    }
    in_atomic = false;
}

/* USB: hardware initialization */
static void usb_hw_init(void)
{
    /* Enable clocking on the required GPIO pins */
    RCC->APB2ENR |= RCC_APB2_GPIOA | RCC_APB2_GPIOC;

    /* Make sure that the CAN controller is disabled and held in reset */
    RCC->APB1ENR &= ~RCC_APB1_CAN;

    /* Configure USB_DM and USB_DP to work as USB lines */
    stm32_gpioPinConfig((struct stm32_gpio *)GPIOA_BASE,
            USB_DM_PIN | USB_DP_PIN,
            GPIO_MODE_AF_PP, GPIO_SPEED_50MHZ);
    /* Configure USB_DISC to work as USB disconnect */
    stm32_gpioPinConfig((struct stm32_gpio *)GPIOC_BASE,
            USB_DISC_PIN,
            GPIO_MODE_OUT_PP, GPIO_SPEED_50MHZ);
    stm32_gpioPinWrite((struct stm32_gpio *)GPIOC_BASE,
                USB_DISC_PIN, 1);

    /* Ensure the USB clock is disabled before setting the prescaler */
    RCC->APB1ENR &= ~RCC_APB1_USB;

    /* Configure USB clock (48MHz) */
    *CFGR_USBPRE_BB &= ~RCC_USBCLK_PLLCLK_1DIV5;

    /* Activate USB clock */
    RCC->APB1ENR |= RCC_APB1_USB;

    /* Force USB reset and disable USB interrupts */
    usb->CNTR = bmFRES;
    timer_delayHp(1);

    /* Issue a USB reset */
    usb_hw_reset();

    /* Clear spurious pending interrupt */
    usb->ISTR = 0;

    /* Register interrupt handler */
    sysirq_setHandler(USB_LP_CAN_RX0_IRQHANDLER, usb_isr);

    /* Software connection enable */
    usb_connect();
}

/* Initialize the USB controller */
static void usb_init(void)
{
    udc.state = USB_STATE_NOTATTACHED;
    udc.feature = 0;

    usb_hw_init();
}

/* Register an upper layer USB device into the driver */
int usb_deviceRegister(UsbDevice *dev)
{
#if CONFIG_KERN
    MOD_CHECK(proc);
#endif
    usb_dev = dev;
    usb_dev->configured = false;

    event_initGeneric(&usb_event_done[0]);
    usb_init();
    event_wait(&usb_event_done[0]);

    return 0;
}