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atsamd5x: improve USBCDC #1481

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Merged
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Feb 16, 2021
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atsamd5x: improve USBCDC #1481

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106 changes: 85 additions & 21 deletions src/machine/machine_atsamd51.go
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@ import (
"device/arm"
"device/sam"
"runtime/interrupt"
"runtime/volatile"
"unsafe"
)

Expand Down Expand Up @@ -1733,36 +1734,93 @@ func (pwm PWM) getMux() PinMode {

// USBCDC is the USB CDC aka serial over USB interface on the SAMD21.
type USBCDC struct {
Buffer *RingBuffer
Buffer *RingBuffer
TxIdx volatile.Register8
waitTxc bool
sent bool
}

// WriteByte writes a byte of data to the USB CDC interface.
func (usbcdc USBCDC) WriteByte(c byte) error {
// Supposedly to handle problem with Windows USB serial ports?
const (
usbcdcTxSizeMask uint8 = 0x3F
usbcdcTxBankMask uint8 = ^usbcdcTxSizeMask
usbcdcTxBank1st uint8 = 0x00
usbcdcTxBank2nd uint8 = usbcdcTxSizeMask + 1
)

// Flush flushes buffered data.
func (usbcdc *USBCDC) Flush() error {
if usbLineInfo.lineState > 0 {
// set the data
udd_ep_in_cache_buffer[usb_CDC_ENDPOINT_IN][0] = c
idx := usbcdc.TxIdx.Get()
sz := idx & usbcdcTxSizeMask
bk := idx & usbcdcTxBankMask
if 0 < sz {

if usbcdc.waitTxc {
// waiting for the next flush(), because the transmission is not complete
return nil
}
usbcdc.waitTxc = true

usbEndpointDescriptors[usb_CDC_ENDPOINT_IN].DeviceDescBank[1].ADDR.Set(uint32(uintptr(unsafe.Pointer(&udd_ep_in_cache_buffer[usb_CDC_ENDPOINT_IN]))))
// set the data
usbEndpointDescriptors[usb_CDC_ENDPOINT_IN].DeviceDescBank[1].ADDR.Set(uint32(uintptr(unsafe.Pointer(&udd_ep_in_cache_buffer[usb_CDC_ENDPOINT_IN][bk]))))
if bk == usbcdcTxBank1st {
usbcdc.TxIdx.Set(usbcdcTxBank2nd)
} else {
usbcdc.TxIdx.Set(usbcdcTxBank1st)
}

// clean multi packet size of bytes already sent
usbEndpointDescriptors[usb_CDC_ENDPOINT_IN].DeviceDescBank[1].PCKSIZE.ClearBits(usb_DEVICE_PCKSIZE_MULTI_PACKET_SIZE_Mask << usb_DEVICE_PCKSIZE_MULTI_PACKET_SIZE_Pos)
// clean multi packet size of bytes already sent
usbEndpointDescriptors[usb_CDC_ENDPOINT_IN].DeviceDescBank[1].PCKSIZE.ClearBits(usb_DEVICE_PCKSIZE_MULTI_PACKET_SIZE_Mask << usb_DEVICE_PCKSIZE_MULTI_PACKET_SIZE_Pos)

// set count of bytes to be sent
usbEndpointDescriptors[usb_CDC_ENDPOINT_IN].DeviceDescBank[1].PCKSIZE.SetBits((1 & usb_DEVICE_PCKSIZE_BYTE_COUNT_Mask) << usb_DEVICE_PCKSIZE_BYTE_COUNT_Pos)
// set count of bytes to be sent
usbEndpointDescriptors[usb_CDC_ENDPOINT_IN].DeviceDescBank[1].PCKSIZE.ClearBits(usb_DEVICE_PCKSIZE_BYTE_COUNT_Mask << usb_DEVICE_PCKSIZE_BYTE_COUNT_Pos)
usbEndpointDescriptors[usb_CDC_ENDPOINT_IN].DeviceDescBank[1].PCKSIZE.SetBits((uint32(sz) & usb_DEVICE_PCKSIZE_BYTE_COUNT_Mask) << usb_DEVICE_PCKSIZE_BYTE_COUNT_Pos)

// clear transfer complete flag
setEPINTFLAG(usb_CDC_ENDPOINT_IN, sam.USB_DEVICE_ENDPOINT_EPINTFLAG_TRCPT1)
// clear transfer complete flag
setEPINTFLAG(usb_CDC_ENDPOINT_IN, sam.USB_DEVICE_ENDPOINT_EPINTFLAG_TRCPT1)

// send data by setting bank ready
setEPSTATUSSET(usb_CDC_ENDPOINT_IN, sam.USB_DEVICE_ENDPOINT_EPSTATUSSET_BK1RDY)
// send data by setting bank ready
setEPSTATUSSET(usb_CDC_ENDPOINT_IN, sam.USB_DEVICE_ENDPOINT_EPSTATUSSET_BK1RDY)
UART0.sent = true
}
}
return nil
}

// wait for transfer to complete
timeout := 3000
for (getEPINTFLAG(usb_CDC_ENDPOINT_IN) & sam.USB_DEVICE_ENDPOINT_EPINTFLAG_TRCPT1) == 0 {
timeout--
if timeout == 0 {
return errUSBCDCWriteByteTimeout
// WriteByte writes a byte of data to the USB CDC interface.
func (usbcdc *USBCDC) WriteByte(c byte) error {
// Supposedly to handle problem with Windows USB serial ports?
if usbLineInfo.lineState > 0 {
ok := false
for {
mask := interrupt.Disable()

idx := UART0.TxIdx.Get()
if (idx & usbcdcTxSizeMask) < usbcdcTxSizeMask {
udd_ep_in_cache_buffer[usb_CDC_ENDPOINT_IN][idx] = c
UART0.TxIdx.Set(idx + 1)
ok = true
}

interrupt.Restore(mask)

if ok {
break
} else {
mask := interrupt.Disable()
if UART0.sent {
if UART0.waitTxc {
if (getEPINTFLAG(usb_CDC_ENDPOINT_IN) & sam.USB_DEVICE_ENDPOINT_EPINTFLAG_TRCPT1) != 0 {
setEPSTATUSCLR(usb_CDC_ENDPOINT_IN, sam.USB_DEVICE_ENDPOINT_EPSTATUSCLR_BK1RDY)
setEPINTFLAG(usb_CDC_ENDPOINT_IN, sam.USB_DEVICE_ENDPOINT_EPINTFLAG_TRCPT1)
UART0.waitTxc = false
UART0.Flush()
}
} else {
UART0.Flush()
}
}
interrupt.Restore(mask)
}
}
}
Expand Down Expand Up @@ -1971,9 +2029,15 @@ func handleUSBIRQ(interrupt.Interrupt) {
case usb_CDC_ENDPOINT_IN, usb_CDC_ENDPOINT_ACM:
setEPSTATUSCLR(i, sam.USB_DEVICE_ENDPOINT_EPSTATUSCLR_BK1RDY)
setEPINTFLAG(i, sam.USB_DEVICE_ENDPOINT_EPINTFLAG_TRCPT1)

if i == usb_CDC_ENDPOINT_IN {
UART0.waitTxc = false
}
}
}
}

UART0.Flush()
}

func initEndpoint(ep, config uint32) {
Expand Down