ep_read and ep_write revised

Now it can be called asynchronously

inc/usbd_core.h

@@ -197,9 +197,9 @@ typedef void (*usbd_hw_ep_deconfig)(uint8_t ep);
  * \param ep endpoint index, should belong to OUT or CONTROL endpoint.
  * \param buf pointer to read buffer
  * \param blen size of the read buffer in bytes
- * \return size of the actually received data
+ * \return size of the actually received data, -1 on error.
  */
-typedef uint16_t (*usbd_hw_ep_read)(uint8_t ep, void *buf, uint16_t blen);
+typedef int32_t (*usbd_hw_ep_read)(uint8_t ep, void *buf, uint16_t blen);
 
 /** Writes data to IN or control endpoint
  * \param ep endpoint index, hould belong to IN or CONTROL endpoint
@@ -207,7 +207,7 @@ typedef uint16_t (*usbd_hw_ep_read)(uint8_t ep, void *buf, uint16_t blen);
  * \param blen size of data will be written
  * \return number of written bytes
  */
-typedef uint16_t (*usbd_hw_ep_write)(uint8_t ep, void *buf, uint16_t blen);
+typedef int32_t (*usbd_hw_ep_write)(uint8_t ep, void *buf, uint16_t blen);
 
 /** Stalls and unstalls endpoint
  * \param ep endpoint address

src/usb_32v0.c

@@ -25,7 +25,10 @@
 #define EP_TX_VALID(epr)    EP_TOGGLE_SET((epr), USB_EP_TX_VALID,                   USB_EPTX_STAT)
 #define EP_RX_VALID(epr)    EP_TOGGLE_SET((epr), USB_EP_RX_VALID,                   USB_EPRX_STAT)
 
-
+typedef struct {
+    uint16_t    addr;
+    uint16_t    cnt;
+} pma_rec;
 
 typedef union pma_table {
     struct {
@@ -46,6 +49,18 @@ typedef union pma_table {
     uint16_t    rxadr1;
     uint16_t    rxcnt1;
     };
+    struct {
+    pma_rec     tx;
+    pma_rec     rx;
+    };
+    struct {
+    pma_rec     tx0;
+    pma_rec     tx1;
+    };
+    struct {
+    pma_rec     rx0;
+    pma_rec     rx1;
+    };
 } pma_table;
 
 
@@ -241,21 +256,15 @@ void ep_deconfig(uint8_t ep) {
     ept->txcnt = 0;
 }
 
+static uint16_t pma_read (uint8_t *buf, uint16_t blen, pma_rec *rx) {
+    uint16_t *pma = (void*)(USB_PMAADDR + rx->addr);
+    uint16_t rxcnt = rx->cnt & 0x03FF;
+    rx->cnt &= ~0x3FF;
 
-
-static void pma_write(const uint16_t txadr, const uint8_t *buf, uint16_t blen) {
-    uint16_t *pma = (void*)(USB_PMAADDR + txadr);
-    while (blen > 1) {
-        *pma++ = buf[1] << 8 | buf[0];
-        buf += 2;
-        blen -= 2;
+    if (blen > rxcnt) {
+        blen = rxcnt;
     }
-    if (blen) *pma = *buf;
-}
-
-static void pma_read (const uint16_t rxadr, uint8_t *buf, uint16_t blen, uint16_t rxlen) {
-    uint16_t *pma = (void*)(USB_PMAADDR + rxadr);
-    if (blen > rxlen) blen = rxlen;
+    rxcnt = blen;
     while (blen) {
         uint16_t _t = *pma;
         *buf++ = _t & 0xFF;
@@ -265,103 +274,107 @@ static void pma_read (const uint16_t rxadr, uint8_t *buf, uint16_t blen, uint16_
             blen--;
         } else break;
     }
+    return rxcnt;
 }
 
-uint16_t ep_read(uint8_t ep, void *buf, uint16_t blen) {
+int32_t ep_read(uint8_t ep, void *buf, uint16_t blen) {
     pma_table *tbl = EPT(ep);
     volatile uint16_t *reg = EPR(ep);
-    uint16_t rxlen, rxbuf;
-
-    switch (*reg & (USB_EP_T_FIELD | USB_EP_KIND)) {
-    case (USB_EP_BULK | USB_EP_KIND):
+    switch (*reg & (USB_EPRX_STAT | USB_EP_T_FIELD | USB_EP_KIND)) {
+    /* doublebuffered bulk endpoint */
+    case (USB_EP_RX_VALID | USB_EP_BULK | USB_EP_KIND):
+        /* switching SWBUF if EP is NAKED */
+        switch (*reg & (USB_EP_DTOG_RX | USB_EP_SWBUF_RX)) {
+        case 0:
+        case (USB_EP_DTOG_RX | USB_EP_SWBUF_RX):
+            *reg = (*reg & USB_EPREG_MASK) | USB_EP_SWBUF_RX;
+        default:
+            break;
+        }
         if (*reg & USB_EP_SWBUF_RX) {
-            rxbuf = tbl->rxadr1;
-            rxlen = tbl->rxcnt1 & 0x03FF;
+            return pma_read(buf, blen, &(tbl->rx1));
         } else {
-            rxbuf = tbl->rxadr0;
-            rxlen = tbl->rxcnt0 & 0x03FF;
+            return pma_read(buf, blen, &(tbl->rx0));
         }
-        pma_read(rxbuf, buf, blen, rxlen);
-        break;
-    case USB_EP_ISOCHRONOUS:
+    /* isochronous endpoint */
+    case (USB_EP_RX_VALID | USB_EP_ISOCHRONOUS):
         if (*reg & USB_EP_DTOG_RX) {
-            rxbuf = tbl->rxadr0;
-            rxlen = tbl->rxcnt0 & 0x03FF;
+            return pma_read(buf, blen, &(tbl->rx1));
         } else {
-            rxbuf = tbl->rxadr1;
-            rxlen = tbl->rxcnt1 & 0x03FF;
+            return pma_read(buf, blen, &(tbl->rx0));
         }
-        pma_read(rxbuf, buf, blen, rxlen);
-        break;
-    default:
-        rxbuf = tbl->rxadr;
-        rxlen = tbl->rxcnt & 0x03FF;
-        pma_read(rxbuf, buf, blen, rxlen);
+    /* regular endpoint */
+    case (USB_EP_RX_NAK | USB_EP_BULK):
+    case (USB_EP_RX_NAK | USB_EP_CONTROL):
+    case (USB_EP_RX_NAK | USB_EP_INTERRUPT):
+        {
+        int32_t res = pma_read(buf, blen, &(tbl->rx));
         /* setting endpoint to VALID state */
         EP_RX_VALID(reg);
-        break;
+        return res;
+        }
+    /* invalid or not ready */
+    default:
+        return -1;
     }
-    return rxlen;
 }
 
+static void pma_write(uint8_t *buf, uint16_t blen, pma_rec *tx) {
+    uint16_t *pma = (void*)(USB_PMAADDR + tx->addr);
+    tx->cnt = blen;
+    while (blen > 1) {
+        *pma++ = buf[1] << 8 | buf[0];
+        buf += 2;
+        blen -= 2;
+    }
+    if (blen) *pma = *buf;
+}
 
-
-uint16_t ep_write(uint8_t ep, void *buf, uint16_t blen) {
+int32_t ep_write(uint8_t ep, void *buf, uint16_t blen) {
     pma_table *tbl = EPT(ep);
     volatile uint16_t *reg = EPR(ep);
-    uint16_t txbuf;
-    switch (*reg & (USB_EP_T_FIELD | USB_EP_KIND)) {
-    case (USB_EP_BULK | USB_EP_KIND):
+    switch (*reg & (USB_EPTX_STAT | USB_EP_T_FIELD | USB_EP_KIND)) {
+    /* doublebuffered bulk endpoint */
+    /* it STAT_TX bits can be in NAKED state. No answer about this */
+    case (USB_EP_TX_VALID | USB_EP_BULK | USB_EP_KIND):
+    case (USB_EP_TX_NAK   | USB_EP_BULK | USB_EP_KIND):
         if (*reg & USB_EP_SWBUF_TX) {
-            tbl->txcnt1 = blen;
-            txbuf = tbl->txadr1;
+            pma_write(buf, blen, &(tbl->tx1));
         } else {
-            tbl->txcnt0 = blen;
-            txbuf = tbl->txadr0;
+            pma_write(buf, blen, &(tbl->tx0));
         }
+        *reg = (*reg & USB_EPREG_MASK) | USB_EP_SWBUF_TX;
         break;
-    case USB_EP_ISOCHRONOUS:
-        if (*reg & USB_EP_DTOG_TX) {
-            tbl->txcnt0 = blen;
-            txbuf = tbl->txadr0;
+    /* isochronous endpoint */
+    case (USB_EP_TX_VALID | USB_EP_ISOCHRONOUS):
+        if (!(*reg & USB_EP_DTOG_TX)) {
+            pma_write(buf, blen, &(tbl->tx1));
         } else {
-            tbl->txcnt1 = blen;
-            txbuf = tbl->txadr1;
+            pma_write(buf, blen, &(tbl->tx0));
         }
         break;
-    default:
-        tbl->txcnt = blen;
-        txbuf = tbl->txadr;
-        break;
-    }
-    pma_write(txbuf, buf, blen);
-
-    switch (*reg & (USB_EP_T_FIELD | USB_EP_KIND)) {
-    case (USB_EP_BULK | USB_EP_KIND):
-        /* switching buffer if doublebuffered bulk endpoint */
-        *reg = (*reg & USB_EPREG_MASK) | USB_EP_SWBUF_TX;
-        break;
-    case USB_EP_ISOCHRONOUS:
+    /* regular endpoint */
+    case (USB_EP_TX_NAK | USB_EP_BULK):
+    case (USB_EP_TX_NAK | USB_EP_CONTROL):
+    case (USB_EP_TX_NAK | USB_EP_INTERRUPT):
+        pma_write(buf, blen, &(tbl->tx));
+        EP_TX_VALID(reg);
         break;
+    /* invalid or not ready */
     default:
-        /* set TX valid to start transfer */
-        EP_TX_VALID(reg);
+        return -1;
     }
     return blen;
-
 }
 
 uint16_t get_frame (void) {
     return USB->FNR & USB_FNR_FN;
 }
 
-
-
 void evt_poll(usbd_device *dev, usbd_evt_callback callback) {
     uint8_t _ev, _ep;
     uint16_t _istr = USB->ISTR;
     _ep = _istr & USB_ISTR_EP_ID;
-
     if (_istr & USB_ISTR_CTR) {
         volatile uint16_t *reg = EPR(_ep);
         if (*reg & USB_EP_CTR_TX) {
@@ -369,13 +382,7 @@ void evt_poll(usbd_device *dev, usbd_evt_callback callback) {
             _ep |= 0x80;
             _ev = usbd_evt_eptx;
         } else {
-            /* clearing CTR */
-            if ((*reg & (USB_EP_T_FIELD | USB_EP_KIND)) == (USB_EP_BULK | USB_EP_KIND)) {
-                /* switching RX buffer and if doublebuffered bulk endpoint */
-                *reg = (*reg & (USB_EPREG_MASK ^ USB_EP_CTR_RX)) | USB_EP_SWBUF_RX;
-            } else {
-                *reg &= (USB_EPREG_MASK ^ USB_EP_CTR_RX);
-            }
+            *reg &= (USB_EPREG_MASK ^ USB_EP_CTR_RX);
             _ev = (*reg & USB_EP_SETUP) ? usbd_evt_epsetup : usbd_evt_eprx;
         }
     } else if (_istr & USB_ISTR_RESET) {

src/usb_32v0A.S

@@ -326,11 +326,11 @@ _ep_isstalled:
 
     .thumb_func
     .type       _ep_read, %function
-/* uint16_t _ep_read(uint8_t ep, void *buf, uint16_t blen)
+/* int32_t _ep_read(uint8_t ep, void *buf, uint16_t blen)
  * in  R0 <- endpoint
  * in  R1 <- *buffer
  * in  R2 <- length of the buffer
- * out length of the recieved data -> R0
+ * out length of the recieved data -> R0 or -1 on error
  */
 _ep_read:
     push    {r4, r5, lr}
@@ -341,61 +341,82 @@ _ep_read:
     adds    r3, r0          // *EPR -> R3
     lsls    r0, #1
     adds    r4, r0          // *EPT -> R4
-    ldrh    r0, [r3]        // reading epr
-    lsls    r5, r0, #21
-    lsrs    r5, #29
-    cmp     r5, #0x04
+    ldrh    r5, [r3]        // reading epr
+/* validating endpoint */
+    movs    r0, #0x37
+    lsls    r0, #0x08
+    ands    r0, r5
+    lsrs    r0, #0x08
+    cmp     r0, #0x34       // (OK) RX_VALID + ISO
     beq     .L_epr_iso
-    cmp     r5, #0x01
-    bne     .L_epr_sngl
-.L_epr_dblbulk:
-    negs    r0, r0
-    lsrs    r0, #7          // ~SW_RX in CF
-    b       .L_epr_load_table
+    cmp     r0, #0x31       // (OK) RX_VALID + DBLBULK
+    beq     .L_epr_dbl
+    cmp     r0, #0x20       // (OK) RX_NAKED + BULK
+    beq     .L_epr_sngl
+    cmp     r0, #0x22       // (OK) RX_NAKED + CTRL
+    beq     .L_epr_sngl
+    cmp     r0, #0x26       // (OK) RX_NAKED + INTR
+    beq     .L_epr_sngl
+    movs    r0, #0xFF       // endpoint contains no valid data
+    sxtb    r0, r0
+    b       .L_epr_exit
+/* processing */
+.L_epr_dbl:
+    lsrs    r0, r5, #8
+    eors    r0, r5
+    lsrs    r0, #6          // SW_RX ^ DTOG_RX -> CF
+    bcc     .L_epr_notog    // jmp if SW_RX != DTOG_RX (VALID)
+    ldr     r0, =#EP_NOTOG
+    ands    r5, r0
+    adds    r5, #EP_RX_SWBUF
+    strh    r5, [r3]        // toggling SW_RX
+    ldrh    r5, [r3]
+.L_epr_notog:
+    negs    r5, r5
+    lsls    r5, #8          // shift ~SW_RX to DTOG_RX
 .L_epr_iso:
-    lsrs    r0, #15         // DTOG_RX passsed to CF
-.L_epr_load_table:
-    ldrh    r0, [r4, #0]    // R0 rxaddr0
-    ldrh    r5, [r4, #2]    // R5 rxcnt0
-    bcs     .L_epr_prepare
+    lsrs    r5, #15         // DTOG_RX -> CF
+    bcc     .L_epr_sngl
+    subs    r4, #0x04       // set RXADDR0
 .L_epr_sngl:
-    ldrh    r0, [r4, #4]    // R0 rxaddr1 or rxaddr
-    ldrh    r5, [r4, #6]    // R5 rxcnt1 or rxcnt
-.L_epr_prepare:
+    ldrh    r0, [r4, #RXCOUNT]
+    lsrs    r5, r0, #0x0A
+    lsls    r5, #0x0A       // r5 = r0 & ~0x03FF
+    strh    r5, [r4, #RXCOUNT]
+    lsls    r0, #22
+    lsrs    r0, #22         // r0 &= 0x3FF (RX count)
+    ldrh    r5, [r4, #RXADDR]
     ldr     r4, =#USB_PMABASE
-    adds    r0, r4          // R0 now has a physical address
-    lsls    r5, #22
-    lsrs    r5, #22         // R5 bytes count
-    cmp     r2, r5
+    adds    r5, r4          // R5 now has a physical address
+    cmp     r2, r0
     blo     .L_epr_read
-    mov     r2, r5          // if buffer is larger
+    mov     r2, r0          // if buffer is larger
 .L_epr_read:
     cmp     r2, #1
     blo     .L_epr_read_end
-    ldrh    r4, [r0]
+    ldrh    r4, [r5]
     strb    r4, [r1]
     beq     .L_epr_read_end
     lsrs    r4, #8
     strb    r4, [r1, #1]
     adds    r1, #2
-    adds    r0, #2
+    adds    r5, #2
     subs    r2, #2
-    bne     .L_epr_read
+    bhi     .L_epr_read
 .L_epr_read_end:
-    ldrh    r0, [r3]
-    lsls    r1, r0, #21
+    ldrh    r5, [r3]        // reload EPR
+    lsls    r1, r5, #21
     lsrs    r1, #29
     cmp     r1, #0x04
     beq     .L_epr_exit     // ep is iso. no needs to set it to valid
     cmp     r1, #0x01
     beq     .L_epr_exit     // ep is dblbulk. no needs to set it to valid
     ldr     r2, =#TGL_SET(EP_RX_STAT , EP_RX_VAL)
-    eors    r0, r2
+    eors    r5, r2
     lsrs    r2, #16
-    ands    r0, r2
-    strh    r0, [r3]        // set ep to VALID state
+    ands    r5, r2
+    strh    r5, [r3]        // set ep to VALID state
 .L_epr_exit:
-    mov     r0, r5
     pop     {r4, r5, pc}
     .size   _ep_read, . - _ep_read
 
@@ -403,81 +424,88 @@ _ep_read:
 
     .thumb_func
     .type   _ep_write, %function
-/* uint16_t ep_write(uint8_t ep, void *buf, uint16_t blen)
+/* int32_t ep_write(uint8_t ep, void *buf, uint16_t blen)
+ * R0 -> endpoint
+ * R1 -> *buffer
+ * R2 -> data length
  *
-
  */
 _ep_write:
-    push    {r2, r4, r5, lr}
+    push    {r4, r5, r6, lr}
     ldr     r3, =#USB_EPBASE
     ldr     r4, =#USB_PMABASE
     lsls    r0, #28
     lsrs    r0, #26
     adds    r3, r0          // *EPR -> R3
     lsls    r0, #1
-    adds    r4, r0          // *EPT -> R4
-    ldrh    r0, [r3]        // reading epr
-    lsls    r0, #21
-    lsrs    r0, #29
-    subs    r0, #0x04
+    adds    r4, r0          // TXADDR0 -> R4
+    ldrh    r5, [r3]        // reading epr
+    movs    r0, #0x73
+    lsls    r0, #4
+    ands    r0, r5
+    lsrs    r0, #4
+    cmp     r0, #0x43       // (OK) TX_VALID + ISO
     beq     .L_epw_iso
-    adds    r0, #0x03
-    bne     .L_epw_sngl
-.L_epw_dblbulk:
-    ldrh    r0, [r3]
-    lsrs    r0, #15          // SW_TX in CF
-    bcc     .L_epw_sngl
-    b       .L_epw_settx1
+    cmp     r0, #0x13       // (OK) TX_VALID + DBLBULK
+    beq     .L_epw_dbl
+    cmp     r0, #0x12       // (OK) TX_NAK + DBLBULK
+    beq     .L_epw_dbl
+    cmp     r0, #0x02       // (OK) TX_NAK + BULK
+    beq     .L_epw_sngl
+    cmp     r0, #0x22       // (OK) TX_NAK + CONTROL
+    beq     .L_epw_sngl
+    cmp     r0, #0x62       // (OK) TX_NAK + INTERRUPT
+    beq     .L_epw_sngl
+    movs    r0, #0xFF
+    sxtb    r0, r0
+    b       .L_epw_exit
+.L_epw_dbl:
+    negs    r5, r5
+    lsrs    r5, #8          // ~SWBUF_TX -> DTOG_TX
 .L_epw_iso:
-    ldrh    r0, [r3]
-    lsrs    r0, #7          // DTOG_TX passsed to CF
+    lsrs    r5, #7          // DTOG_TX -> CF
     bcs     .L_epw_sngl
-.L_epw_settx1:
-    adds    r4, #0x04
+    adds    r4, #4          // TXADDR1 -> R4
 .L_epw_sngl:
-    ldrh    r0, [r4, #0]    // R0 txaddr
-.L_epw_prepare:
-    strh    r2, [r4, #2]    // set txcount
+    strh    r2, [r4, #TXCOUNT]
+    mov     r0, r2          // save count for return
+    ldrh    r5, [r4, #TXADDR]
     ldr     r4, =#USB_PMABASE
-    adds    r0, r4
+    adds    r5, r4          // PMA BUFFER -> R5
 .L_epw_write:
-    cmp     r2, #0x01
-    blo     .L_epw_writeend
+    cmp     r2, #1
+    blo     .L_epw_write_end
     ldrb    r4, [r1]
-    beq     .L_epw_halfw
-    ldrb    r5, [r1, #1]
-    lsls    r5, #8
-    orrs    r4, r5
-    strh    r4, [r0]
+    beq     .L_epw_store
+    ldrb    r6, [r1, #1]
+    lsls    r6, #8
+    orrs    r4, r6
+.L_epw_store:
+    strh    r4, [r5]
+    adds    r5, #2
     adds    r1, #2
-    adds    r0, #2
     subs    r2, #2
-    b       .L_epw_write
-.L_epw_halfw:
-    strh    r4, [r0]
-.L_epw_writeend:
-    ldrh    r0, [r3]
-    lsls    r1, r0, #21
+    bhi     .L_epw_write
+.L_epw_write_end:
+    ldrh    r5, [r3]        // reload EPR
+    lsls    r1, r5, #21
     lsrs    r1, #29
     cmp     r1, #0x04
-    beq     .L_epw_exit        //nothing to do with ISO ep
+    beq     .L_epw_exit     // isochronous ep. do nothing
     ldr     r2, =#TGL_SET(EP_TX_STAT, EP_TX_VAL)
     cmp     r1, #0x01
-    bne     .L_epw_setstate
-// ep is dblbulk. needs to switch SW_TX
+    bne     .L_epw_setstate // NOT a doublebuffered bulk
     ldr     r2, =#TGL_SET(EP_TX_SWBUF, EP_TX_SWBUF)
-    bics    r0, r2              //clearing SW_BUF for setting in to 1 by XOR
- .L_epw_setstate:
-    eors    r0, r2
+    bics    r5, r2          // clear TX_SWBUF
+.L_epw_setstate:
+    eors    r5, r2
     lsrs    r2, #16
-    ands    r0, r2
-    strh    r0, [r3]
+    ands    r5, r2
+    strh    r5, [r3]
 .L_epw_exit:
-    pop     {r0, r4, r5, pc}
+    pop     {r4, r5, r6, pc}
     .size   _ep_write, .- _ep_write
 
-
-
 /* internal function */
 /* requester size passed in R2 */
 /* result returns in R0 CF=1 if OK*/
@@ -701,40 +729,30 @@ _evt_poll:
     bx      lr
 
 .L_ep_ctrm:
-    movs    r3, #0x00
+    movs    r5, #0x80           // CTR_TX mask to R5
     ldr     r0,=#USB_EPBASE
     lsrs    r0, #2
     adds    r0, r2
     lsls    r0, #2              // R0 ep register address
-    ldrh    r4, [r0]            //R4 *USB->EPx
-    lsrs    r5, r4, #8         // CTR_TX -> CF
+    ldrh    r4, [r0]            // R4 EPR valur
+    lsrs    r3, r4, #8          // CTR_TX -> CF
     bcc     .L_ep_ctr_rx
 /* CTR_TX event */
     movs    r1, #usbd_evt_eptx
-    movs    r5, #0x80
-    adds    r2, #0x80           // set endpoint tx
+    orrs    r2, r5              // set endpoint tx
     b       .L_ep_clr_ctr
 .L_ep_ctr_rx:
 /* CTR_RX  RX or SETUP */
-    movs    r1, #usbd_evt_epsetup
-    lsls    r5, r4, #21             //SETUP -> CF
-    bcs     .L_ep_ctr_evt
+    lsls    r5, #0x08           // set mask to CRT_RX
     movs    r1, #usbd_evt_eprx
-    lsrs    r5, #29                 //EP_TYPE | EP_KIND -> R5 LSB
-    cmp     r5, #0x01               //if dblbuf bulk
-    bne     .L_ep_ctr_evt
-/* if ep is dblbulk RX */
-    movs    r3, #EP_RX_SWBUF
-.L_ep_ctr_evt:
-/* clear CTR_RX */
-    movs    r5, #0x80
-    lsls    r5, #0x08
+    lsls    r3, r4, #21         //SETUP -> CF
+    bcc     .L_ep_clr_ctr
+    movs    r1, #usbd_evt_epsetup
 .L_ep_clr_ctr:
-    bics    r4, r5
+    bics    r4, r5              //clear CTR flag
     ldr     r5, =#EP_NOTOG
     ands    r4, r5
-    orrs    r4, r3
-    strh    r4, [r0]            // clr CTR flag
+    strh    r4, [r0]            // store
     b       .L_ep_callback
 .L_ep_errm:
     movs    r1, #usbd_evt_error

src/usb_32v1.c

@@ -25,7 +25,12 @@
 #define EP_TX_VALID(epr)    EP_TOGGLE_SET((epr), USB_EP_TX_VALID,                   USB_EPTX_STAT)
 #define EP_RX_VALID(epr)    EP_TOGGLE_SET((epr), USB_EP_RX_VALID,                   USB_EPRX_STAT)
 
-
+typedef struct {
+    uint16_t    addr;
+    uint16_t    :16;
+    uint16_t    cnt;
+    uint16_t    :16;
+} pma_rec;
 
 typedef union pma_table {
     struct {
@@ -58,6 +63,18 @@ typedef union pma_table {
     uint16_t    rxcnt1;
     uint16_t    :16;
     };
+    struct {
+    pma_rec     tx;
+    pma_rec     rx;
+    };
+    struct {
+    pma_rec     tx0;
+    pma_rec     tx1;
+    };
+    struct {
+    pma_rec     rx0;
+    pma_rec     rx1;
+    };
 } pma_table;
 
 
@@ -258,22 +275,14 @@ void ep_deconfig(uint8_t ep) {
     ept->txcnt = 0;
 }
 
-
-
-static void pma_write(const uint16_t txadr, const uint8_t *buf, uint16_t blen) {
-    uint16_t *pma = (void*)(USB_PMAADDR + 2 * txadr);
-    while (blen > 1) {
-        *pma = buf[1] << 8 | buf[0];
-        pma += 2;
-        buf += 2;
-        blen -= 2;
+static uint16_t pma_read (uint8_t *buf, uint16_t blen, pma_rec *rx) {
+    uint16_t *pma = (void*)(USB_PMAADDR + 2 * rx->addr);
+    uint16_t rxcnt = rx->cnt & 0x03FF;
+    rx->cnt &= ~0x3FF;
+    if (blen > rxcnt) {
+        blen = rxcnt;
     }
-    if (blen) *pma = *buf;
-}
-
-static void pma_read (const uint16_t rxadr, uint8_t *buf, uint16_t blen, uint16_t rxlen) {
-    uint16_t *pma = (void*)(USB_PMAADDR + 2 * rxadr);
-    if (blen > rxlen) blen = rxlen;
+    rxcnt = blen;
     while (blen) {
         uint16_t _t = *pma;
         *buf++ = _t & 0xFF;
@@ -283,98 +292,104 @@ static void pma_read (const uint16_t rxadr, uint8_t *buf, uint16_t blen, uint16_
             blen--;
         } else break;
     }
+    return rxcnt;
 }
 
-uint16_t ep_read(uint8_t ep, void *buf, uint16_t blen) {
+int32_t ep_read(uint8_t ep, void *buf, uint16_t blen) {
     pma_table *tbl = EPT(ep);
     volatile uint16_t *reg = EPR(ep);
-    uint16_t rxlen, rxbuf;
-
-    switch (*reg & (USB_EP_T_FIELD | USB_EP_KIND)) {
-    case (USB_EP_BULK | USB_EP_KIND):
+    switch (*reg & (USB_EPRX_STAT | USB_EP_T_FIELD | USB_EP_KIND)) {
+    /* doublebuffered bulk endpoint */
+    case (USB_EP_RX_VALID | USB_EP_BULK | USB_EP_KIND):
+        /* switching SWBUF if EP is NAKED */
+        switch (*reg & (USB_EP_DTOG_RX | USB_EP_SWBUF_RX)) {
+        case 0:
+        case (USB_EP_DTOG_RX | USB_EP_SWBUF_RX):
+            *reg = (*reg & USB_EPREG_MASK) | USB_EP_SWBUF_RX;
+        default:
+            break;
+        }
         if (*reg & USB_EP_SWBUF_RX) {
-            rxbuf = tbl->rxadr1;
-            rxlen = tbl->rxcnt1 & 0x03FF;
+            return pma_read(buf, blen, &(tbl->rx1));
         } else {
-            rxbuf = tbl->rxadr0;
-            rxlen = tbl->rxcnt0 & 0x03FF;
+            return pma_read(buf, blen, &(tbl->rx0));
         }
-        pma_read(rxbuf, buf, blen, rxlen);
-        break;
-    case USB_EP_ISOCHRONOUS:
+    /* isochronous endpoint */
+    case (USB_EP_RX_VALID | USB_EP_ISOCHRONOUS):
         if (*reg & USB_EP_DTOG_RX) {
-            rxbuf = tbl->rxadr0;
-            rxlen = tbl->rxcnt0 & 0x03FF;
+            return pma_read(buf, blen, &(tbl->rx1));
         } else {
-            rxbuf = tbl->rxadr1;
-            rxlen = tbl->rxcnt1 & 0x03FF;
+            return pma_read(buf, blen, &(tbl->rx0));
         }
-        pma_read(rxbuf, buf, blen, rxlen);
-        break;
-    default:
-        rxbuf = tbl->rxadr;
-        rxlen = tbl->rxcnt & 0x03FF;
-        pma_read(rxbuf, buf, blen, rxlen);
+    /* regular endpoint */
+    case (USB_EP_RX_NAK | USB_EP_BULK):
+    case (USB_EP_RX_NAK | USB_EP_CONTROL):
+    case (USB_EP_RX_NAK | USB_EP_INTERRUPT):
+        {
+        int32_t res = pma_read(buf, blen, &(tbl->rx));
         /* setting endpoint to VALID state */
         EP_RX_VALID(reg);
-        break;
+        return res;
+        }
+    /* invalid or not ready */
+    default:
+        return -1;
     }
-    return rxlen;
 }
 
+static void pma_write(const uint8_t *buf, uint16_t blen, pma_rec *tx) {
+    uint16_t *pma = (void*)(USB_PMAADDR + 2 * (tx->addr));
+    tx->cnt = blen;
+    while (blen > 1) {
+        *pma = buf[1] << 8 | buf[0];
+        pma += 2;
+        buf += 2;
+        blen -= 2;
+    }
+    if (blen) *pma = *buf;
+}
 
-
-uint16_t ep_write(uint8_t ep, void *buf, uint16_t blen) {
+int32_t ep_write(uint8_t ep, void *buf, uint16_t blen) {
     pma_table *tbl = EPT(ep);
     volatile uint16_t *reg = EPR(ep);
-    uint16_t txbuf;
-    switch (*reg & (USB_EP_T_FIELD | USB_EP_KIND)) {
-    case (USB_EP_BULK | USB_EP_KIND):
+    switch (*reg & (USB_EPTX_STAT | USB_EP_T_FIELD | USB_EP_KIND)) {
+    /* doublebuffered bulk endpoint */
+    /* it STAT_TX bits can be in NAKED state. No answer about this */
+    case (USB_EP_TX_VALID | USB_EP_BULK | USB_EP_KIND):
+    case (USB_EP_TX_NAK   | USB_EP_BULK | USB_EP_KIND):
         if (*reg & USB_EP_SWBUF_TX) {
-            tbl->txcnt1 = blen;
-            txbuf = tbl->txadr1;
+            pma_write(buf, blen, &(tbl->tx1));
         } else {
-            tbl->txcnt0 = blen;
-            txbuf = tbl->txadr0;
+            pma_write(buf, blen, &(tbl->tx0));
         }
+        *reg = (*reg & USB_EPREG_MASK) | USB_EP_SWBUF_TX;
         break;
-    case USB_EP_ISOCHRONOUS:
-        if (*reg & USB_EP_DTOG_TX) {
-            tbl->txcnt0 = blen;
-            txbuf = tbl->txadr0;
+    /* isochronous endpoint */
+    case (USB_EP_TX_VALID | USB_EP_ISOCHRONOUS):
+        if (!(*reg & USB_EP_DTOG_TX)) {
+            pma_write(buf, blen, &(tbl->tx1));
         } else {
-            tbl->txcnt1 = blen;
-            txbuf = tbl->txadr1;
+            pma_write(buf, blen, &(tbl->tx0));
         }
         break;
-    default:
-        tbl->txcnt = blen;
-        txbuf = tbl->txadr;
-        break;
-    }
-    pma_write(txbuf, buf, blen);
-
-    switch (*reg & (USB_EP_T_FIELD | USB_EP_KIND)) {
-    case (USB_EP_BULK | USB_EP_KIND):
-        /* switching buffer if doublebuffered bulk endpoint */
-        *reg = (*reg & USB_EPREG_MASK) | USB_EP_SWBUF_TX;
-        break;
-    case USB_EP_ISOCHRONOUS:
+    /* regular endpoint */
+    case (USB_EP_TX_NAK | USB_EP_BULK):
+    case (USB_EP_TX_NAK | USB_EP_CONTROL):
+    case (USB_EP_TX_NAK | USB_EP_INTERRUPT):
+        pma_write(buf, blen, &(tbl->tx));
+        EP_TX_VALID(reg);
         break;
+    /* invalid or not ready */
     default:
-        /* set TX valid to start transfer */
-        EP_TX_VALID(reg);
+        return -1;
     }
     return blen;
-
 }
 
 uint16_t get_frame (void) {
     return USB->FNR & USB_FNR_FN;
 }
 
-
-
 void evt_poll(usbd_device *dev, usbd_evt_callback callback) {
     uint8_t _ev, _ep;
     uint16_t _istr = USB->ISTR;
@@ -387,13 +402,7 @@ void evt_poll(usbd_device *dev, usbd_evt_callback callback) {
             _ep |= 0x80;
             _ev = usbd_evt_eptx;
         } else {
-            /* clearing CTR */
-            if ((*reg & (USB_EP_T_FIELD | USB_EP_KIND)) == (USB_EP_BULK | USB_EP_KIND)) {
-                /* switching RX buffer and if doublebuffered bulk endpoint */
-                *reg = (*reg & (USB_EPREG_MASK ^ USB_EP_CTR_RX)) | USB_EP_SWBUF_RX;
-            } else {
-                *reg &= (USB_EPREG_MASK ^ USB_EP_CTR_RX);
-            }
+            *reg &= (USB_EPREG_MASK ^ USB_EP_CTR_RX);
             _ev = (*reg & USB_EP_SETUP) ? usbd_evt_epsetup : usbd_evt_eprx;
         }
     } else if (_istr & USB_ISTR_RESET) {

src/usb_32v1A.S

@@ -338,156 +338,185 @@ _ep_isstalled:
 
     .thumb_func
     .type       _ep_read, %function
-/* uint16_t _ep_read(uint8_t ep, void *buf, uint16_t blen)
+/* int32_t _ep_read(uint8_t ep, void *buf, uint16_t blen)
  * in  R0 <- endpoint
  * in  R1 <- *buffer
  * in  R2 <- length of the buffer
- * out length of the recieved data -> R0
+ * out length of the recieved data -> R0 or 0 on error
  */
 _ep_read:
     push    {r4, r5, lr}
     ldr     r3, =#USB_EPBASE
     ldr     r4, =#USB_PMABASE
-    lsls    r0, #28
+    lsls    r0,  #28
     lsrs    r0, #26
     adds    r3, r0          // *EPR -> R3
     lsls    r0, #2
     adds    r4, r0          // *EPT -> R4
-    ldrh    r0, [r3]        // reading epr
-    lsls    r5, r0, #21
-    lsrs    r5, #29
-    cmp     r5, #0x04
+    ldrh    r5, [r3]        // reading epr
+/* validating endpoint */
+    movs    r0, #0x37
+    lsls    r0, #0x08
+    ands    r0, r5
+    lsrs    r0, #0x08
+    cmp     r0, #0x34       // (OK) RX_VALID + ISO
     beq     .L_epr_iso
-    cmp     r5, #0x01
-    bne     .L_epr_sngl
-.L_epr_dblbulk:
-    negs    r0, r0
-    lsrs    r0, #7          // ~SW_RX in CF
-    b       .L_epr_load_table
+    cmp     r0, #0x31       // (OK) RX_VALID + DBLBULK
+    beq     .L_epr_dbl
+    cmp     r0, #0x20       // (OK) RX_NAKED + BULK
+    beq     .L_epr_sngl
+    cmp     r0, #0x22       // (OK) RX_NAKED + CTRL
+    beq     .L_epr_sngl
+    cmp     r0, #0x26       // (OK) RX_NAKED + INTR
+    beq     .L_epr_sngl
+    movs    r0, #0xFF       // endpoint contains no valid data
+    sxtb    r0, r0
+    b       .L_epr_exit
+/* processing */
+.L_epr_dbl:
+    lsrs    r0, r5, #8
+    eors    r0, r5
+    lsrs    r0, #6          // SW_RX ^ DTOG_RX -> CF
+    bcc     .L_epr_notog    // jmp if SW_RX != DTOG_RX (VALID)
+    ldr     r0, =#EP_NOTOG
+    ands    r5, r0
+    adds    r5, #EP_RX_SWBUF
+    strh    r5, [r3]        // toggling SW_RX
+    ldrh    r5, [r3]
+.L_epr_notog:
+    negs    r5, r5
+    lsls    r5, #8          // shift ~SW_RX to DTOG_RX
 .L_epr_iso:
-    lsrs    r0, #15         // DTOG_RX passsed to CF
-.L_epr_load_table:
-    ldrh    r0, [r4, #RXADDR0]    // R0 rxaddr0
-    ldrh    r5, [r4, #RXCOUNT0]    // R5 rxcnt0
-    bcs     .L_epr_prepare
+    lsrs    r5, #15         // DTOG_RX -> CF
+    bcc     .L_epr_sngl
+    subs    r4, #0x08       // set RXADDR0
 .L_epr_sngl:
-    ldrh    r0, [r4, #RXADDR]    // R0 rxaddr1 or rxaddr
-    ldrh    r5, [r4, #RXCOUNT]   // R5 rxcnt1 or rxcnt
-.L_epr_prepare:
+    ldrh    r0, [r4, #RXCOUNT]
+    lsrs    r5, r0, #0x0A
+    lsls    r5, #0x0A       // r5 = r5 & ~0x03FF
+    strh    r5, [r4, #RXCOUNT]
+    lsls    r0, #22
+    lsrs    r0, #22         // r0 &= 0x3FF (RX count)
+    ldrh    r5, [r4, #RXADDR]
     ldr     r4, =#USB_PMABASE
-    lsls    r0, #0x01
-    adds    r0, r4          // R0 now has a physical address
-    lsls    r5, #22
-    lsrs    r5, #22         // R5 bytes count
-    cmp     r2, r5
+    lsls    r5, #0x01
+    adds    r5, r4          // R5 now has a physical address
+    cmp     r2, r0
     blo     .L_epr_read
-    mov     r2, r5          // if buffer is larger
+    mov     r2, r0          // if buffer is larger
 .L_epr_read:
     cmp     r2, #1
     blo     .L_epr_read_end
-    ldrh    r4, [r0]
+    ldrh    r4, [r5]
     strb    r4, [r1]
     beq     .L_epr_read_end
     lsrs    r4, #8
     strb    r4, [r1, #1]
     adds    r1, #2
-    adds    r0, #4
+    adds    r5, #4
     subs    r2, #2
-    bne     .L_epr_read
+    bhi     .L_epr_read
 .L_epr_read_end:
-    ldrh    r0, [r3]
-    lsls    r1, r0, #21
+    ldrh    r5, [r3]        // reload EPR
+    lsls    r1, r5, #21
     lsrs    r1, #29
     cmp     r1, #0x04
     beq     .L_epr_exit     // ep is iso. no needs to set it to valid
     cmp     r1, #0x01
     beq     .L_epr_exit     // ep is dblbulk. no needs to set it to valid
     ldr     r2, =#TGL_SET(EP_RX_STAT , EP_RX_VAL)
-    eors    r0, r2
+    eors    r5, r2
     lsrs    r2, #16
-    ands    r0, r2
-    strh    r0, [r3]        // set ep to VALID state
+    ands    r5, r2
+    strh    r5, [r3]        // set ep to VALID state
 .L_epr_exit:
-    mov     r0, r5
     pop     {r4, r5, pc}
     .size   _ep_read, . - _ep_read
 
 
-
     .thumb_func
     .type   _ep_write, %function
-/* uint16_t ep_write(uint8_t ep, void *buf, uint16_t blen)
- *
-
+/* int32_t ep_write(uint8_t ep, void *buf, uint16_t blen)
+ * R0 -> endpoint
+ * R1 -> *buffer
+ * R2 -> data length
+ * result -> R0
  */
 _ep_write:
-    push    {r2, r4, r5, lr}
+    push    {r4, r5, r6, lr}
     ldr     r3, =#USB_EPBASE
     ldr     r4, =#USB_PMABASE
     lsls    r0, #28
     lsrs    r0, #26
     adds    r3, r0          // *EPR -> R3
     lsls    r0, #2
-    adds    r4, r0          // *EPT -> R4
-    ldrh    r0, [r3]        // reading epr
-    lsls    r0, #21
-    lsrs    r0, #29
-    subs    r0, #0x04
+    adds    r4, r0          // TXADDR0 -> R4
+    ldrh    r5, [r3]        // reading epr
+    movs    r0, #0x73
+    lsls    r0, #4
+    ands    r0, r5
+    lsrs    r0, #4
+    cmp     r0, #0x43       // (OK) TX_VALID + ISO
     beq     .L_epw_iso
-    adds    r0, #0x03
-    bne     .L_epw_sngl
-.L_epw_dblbulk:
-    ldrh    r0, [r3]
-    lsrs    r0, #15          // SW_TX in CF
-    bcc     .L_epw_sngl
-    b       .L_epw_settx1
+    cmp     r0, #0x13       // (OK) TX_VALID + DBLBULK
+    beq     .L_epw_dbl
+    cmp     r0, #0x12       // (OK) TX_NAK + DBLBULK
+    beq     .L_epw_dbl
+    cmp     r0, #0x02       // (OK) TX_NAK + BULK
+    beq     .L_epw_sngl
+    cmp     r0, #0x22       // (OK) TX_NAK + CONTROL
+    beq     .L_epw_sngl
+    cmp     r0, #0x62       // (OK) TX_NAK + INTERRUPT
+    beq     .L_epw_sngl
+    movs    r0, #0xFF
+    sxtb    r0, r0
+    b       .L_epw_exit
+.L_epw_dbl:
+    negs    r5, r5
+    lsrs    r5, #8          // ~SWBUF_TX -> DTOG_TX
 .L_epw_iso:
-    ldrh    r0, [r3]
-    lsrs    r0, #7          // DTOG_TX passsed to CF
+    lsrs    r5, #7          // DTOG_TX -> CF
     bcs     .L_epw_sngl
-.L_epw_settx1:
-    adds    r4, #0x08
+    adds    r4, #8          // TXADDR1 -> R4
 .L_epw_sngl:
-    ldrh    r0, [r4, #TXADDR]    // R0 txaddr
-    lsls    r0, #0x01
-//.L_epw_prepare:
-    strh    r2, [r4, #TXCOUNT]   // set txcount
+    strh    r2, [r4, #TXCOUNT]
+    mov     r0, r2          // save count for return
+    ldrh    r5, [r4, #TXADDR]
     ldr     r4, =#USB_PMABASE
-    adds    r0, r4
+    lsls    r5, #1
+    adds    r5, r4          // PMA BUFFER -> R5
 .L_epw_write:
-    cmp     r2, #0x01
-    blo     .L_epw_writeend
+    cmp     r2, #1
+    blo     .L_epw_write_end
     ldrb    r4, [r1]
-    beq     .L_epw_halfw
-    ldrb    r5, [r1, #1]
-    lsls    r5, #8
-    orrs    r4, r5
-    strh    r4, [r0]
+    beq     .L_epw_store
+    ldrb    r6, [r1, #1]
+    lsls    r6, #8
+    orrs    r4, r6
+.L_epw_store:
+    strh    r4, [r5]
+    adds    r5, #4
     adds    r1, #2
-    adds    r0, #4
     subs    r2, #2
-    b       .L_epw_write
-.L_epw_halfw:
-    strh    r4, [r0]
-.L_epw_writeend:
-    ldrh    r0, [r3]
-    lsls    r1, r0, #21
+    bhi     .L_epw_write
+.L_epw_write_end:
+    ldrh    r5, [r3]        // reload EPR
+    lsls    r1, r5, #21
     lsrs    r1, #29
     cmp     r1, #0x04
-    beq     .L_epw_exit        //nothing to do with ISO ep
+    beq     .L_epw_exit     // isochronous ep. do nothing
     ldr     r2, =#TGL_SET(EP_TX_STAT, EP_TX_VAL)
     cmp     r1, #0x01
-    bne     .L_epw_setstate
-// ep is dblbulk. needs to switch SW_TX
+    bne     .L_epw_setstate // NOT a doublebuffered bulk
     ldr     r2, =#TGL_SET(EP_TX_SWBUF, EP_TX_SWBUF)
-    bics    r0, r2              //clearing SW_BUF for setting in to 1 by XOR
- .L_epw_setstate:
-    eors    r0, r2
+    bics    r5, r2          // clear TX_SWBUF
+.L_epw_setstate:
+    eors    r5, r2
     lsrs    r2, #16
-    ands    r0, r2
-    strh    r0, [r3]
+    ands    r5, r2
+    strh    r5, [r3]
 .L_epw_exit:
-    pop     {r0, r4, r5, pc}
+    pop     {r4, r5, r6, pc}
     .size   _ep_write, .- _ep_write
 
 
@@ -715,42 +744,31 @@ _evt_poll:
     bx      lr
 
 .L_ep_ctrm:
-    movs    r3, #0x00
+    movs    r5, #0x80           // CTR_TX mask to R5
     ldr     r0,=#USB_EPBASE
     lsrs    r0, #2
     adds    r0, r2
     lsls    r0, #2              // R0 ep register address
-    ldrh    r4, [r0]            //R4 *USB->EPx
-    lsrs    r5, r4, #8         // CTR_TX -> CF
+    ldrh    r4, [r0]            // R4 EPR valur
+    lsrs    r3, r4, #8          // CTR_TX -> CF
     bcc     .L_ep_ctr_rx
 /* CTR_TX event */
     movs    r1, #usbd_evt_eptx
-    movs    r5, #0x80
-    adds    r2, #0x80           // set endpoint tx
+    orrs    r2, r5              // set endpoint tx
     b       .L_ep_clr_ctr
 .L_ep_ctr_rx:
 /* CTR_RX  RX or SETUP */
-    movs    r1, #usbd_evt_epsetup
-    lsls    r5, r4, #21             //SETUP -> CF
-    bcs     .L_ep_ctr_evt
+    lsls    r5, #0x08           // set mask to CRT_RX
     movs    r1, #usbd_evt_eprx
-    lsrs    r5, #29                 //EP_TYPE | EP_KIND -> R5 LSB
-    cmp     r5, #0x01               //if dblbuf bulk
-    bne     .L_ep_ctr_evt
-/* if ep is dblbulk RX */
-    movs    r3, #EP_RX_SWBUF
-.L_ep_ctr_evt:
-/* clear CTR_RX */
-    movs    r5, #0x80
-    lsls    r5, #0x08
+    lsls    r3, r4, #21         //SETUP -> CF
+    bcc     .L_ep_clr_ctr
+    movs    r1, #usbd_evt_epsetup
 .L_ep_clr_ctr:
-    bics    r4, r5
+    bics    r4, r5              //clear CTR flag
     ldr     r5, =#EP_NOTOG
     ands    r4, r5
-    orrs    r4, r3
-    strh    r4, [r0]            // clr CTR flag
+    strh    r4, [r0]            // store
     b       .L_ep_callback
-
 .L_ep_errm:
     movs    r1, #usbd_evt_error
     movs    r4, #ISTRBIT(13)