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-rw-r--r--ports/stm32/usbd_cdc_interface.c72
-rw-r--r--ports/stm32/usbd_cdc_interface.h4
2 files changed, 47 insertions, 29 deletions
diff --git a/ports/stm32/usbd_cdc_interface.c b/ports/stm32/usbd_cdc_interface.c
index a0e19de97..7a0912852 100644
--- a/ports/stm32/usbd_cdc_interface.c
+++ b/ports/stm32/usbd_cdc_interface.c
@@ -171,32 +171,56 @@ int8_t usbd_cdc_control(usbd_cdc_state_t *cdc_in, uint8_t cmd, uint8_t *pbuf, ui
return USBD_OK;
}
+static inline uint16_t usbd_cdc_tx_buffer_mask(uint16_t val) {
+ return val & (USBD_CDC_TX_DATA_SIZE - 1);
+}
+
+static inline uint16_t usbd_cdc_tx_buffer_size(usbd_cdc_itf_t *cdc) {
+ return cdc->tx_buf_ptr_in - cdc->tx_buf_ptr_out;
+}
+
+static inline bool usbd_cdc_tx_buffer_empty(usbd_cdc_itf_t *cdc) {
+ return cdc->tx_buf_ptr_out == cdc->tx_buf_ptr_in;
+}
+
+static inline bool usbd_cdc_tx_buffer_will_be_empty(usbd_cdc_itf_t *cdc) {
+ return cdc->tx_buf_ptr_out_next == cdc->tx_buf_ptr_in;
+}
+
+static inline bool usbd_cdc_tx_buffer_full(usbd_cdc_itf_t *cdc) {
+ return usbd_cdc_tx_buffer_size(cdc) == USBD_CDC_TX_DATA_SIZE;
+}
+
+static uint16_t usbd_cdc_tx_send_length(usbd_cdc_itf_t *cdc) {
+ uint16_t to_end = USBD_CDC_TX_DATA_SIZE - usbd_cdc_tx_buffer_mask(cdc->tx_buf_ptr_out);
+ return MIN(usbd_cdc_tx_buffer_size(cdc), to_end);
+}
+
+static void usbd_cdc_tx_buffer_put(usbd_cdc_itf_t *cdc, uint8_t data) {
+ cdc->tx_buf[usbd_cdc_tx_buffer_mask(cdc->tx_buf_ptr_in)] = data;
+ cdc->tx_buf_ptr_in++;
+}
+
+static uint8_t *usbd_cdc_tx_buffer_getp(usbd_cdc_itf_t *cdc, uint16_t len) {
+ cdc->tx_buf_ptr_out_next += len;
+ return &cdc->tx_buf[usbd_cdc_tx_buffer_mask(cdc->tx_buf_ptr_out)];
+}
+
// Called when the USB IN endpoint is ready to receive more data
// (cdc.base.tx_in_progress must be 0)
void usbd_cdc_tx_ready(usbd_cdc_state_t *cdc_in) {
usbd_cdc_itf_t *cdc = (usbd_cdc_itf_t *)cdc_in;
- cdc->tx_buf_ptr_out = cdc->tx_buf_ptr_out_shadow;
+ cdc->tx_buf_ptr_out = cdc->tx_buf_ptr_out_next;
- if (cdc->tx_buf_ptr_out == cdc->tx_buf_ptr_in && !cdc->tx_need_empty_packet) {
+ if (usbd_cdc_tx_buffer_empty(cdc) && !cdc->tx_need_empty_packet) {
// No outstanding data to send
return;
}
-
- uint32_t len;
- if (cdc->tx_buf_ptr_out > cdc->tx_buf_ptr_in) { // rollback
- len = USBD_CDC_TX_DATA_SIZE - cdc->tx_buf_ptr_out;
- } else {
- len = cdc->tx_buf_ptr_in - cdc->tx_buf_ptr_out;
- }
-
+ uint16_t len = usbd_cdc_tx_send_length(cdc);
// Should always succeed because cdc.base.tx_in_progress==0
- USBD_CDC_TransmitPacket(&cdc->base, len, &cdc->tx_buf[cdc->tx_buf_ptr_out]);
+ USBD_CDC_TransmitPacket(&cdc->base, len, usbd_cdc_tx_buffer_getp(cdc, len));
- cdc->tx_buf_ptr_out_shadow += len;
- if (cdc->tx_buf_ptr_out_shadow == USBD_CDC_TX_DATA_SIZE) {
- cdc->tx_buf_ptr_out_shadow = 0;
- }
// According to the USB specification, a packet size of 64 bytes (CDC_DATA_FS_MAX_PACKET_SIZE)
// gets held at the USB host until the next packet is sent. This is because a
@@ -204,7 +228,7 @@ void usbd_cdc_tx_ready(usbd_cdc_state_t *cdc_in) {
// the host waits for all data to arrive (ie, waits for a packet < max packet size).
// To flush a packet of exactly max packet size, we need to send a zero-size packet.
// See eg http://www.cypress.com/?id=4&rID=92719
- cdc->tx_need_empty_packet = (len > 0 && len % usbd_cdc_max_packet(cdc->base.usbd->pdev) == 0 && cdc->tx_buf_ptr_out_shadow == cdc->tx_buf_ptr_in);
+ cdc->tx_need_empty_packet = (len > 0 && len % usbd_cdc_max_packet(cdc->base.usbd->pdev) == 0 && usbd_cdc_tx_buffer_will_be_empty(cdc));
}
// Attempt to queue data on the USB IN endpoint
@@ -291,10 +315,7 @@ int8_t usbd_cdc_receive(usbd_cdc_state_t *cdc_in, size_t len) {
}
int usbd_cdc_tx_half_empty(usbd_cdc_itf_t *cdc) {
- int32_t tx_waiting = (int32_t)cdc->tx_buf_ptr_in - (int32_t)cdc->tx_buf_ptr_out;
- if (tx_waiting < 0) {
- tx_waiting += USBD_CDC_TX_DATA_SIZE;
- }
+ int32_t tx_waiting = usbd_cdc_tx_buffer_size(cdc);
return tx_waiting <= USBD_CDC_TX_DATA_SIZE / 2;
}
@@ -317,8 +338,7 @@ int usbd_cdc_tx(usbd_cdc_itf_t *cdc, const uint8_t *buf, uint32_t len, uint32_t
for (uint32_t i = 0; i < len; i++) {
// Wait until the device is connected and the buffer has space, with a given timeout
uint32_t start = HAL_GetTick();
- while (cdc->connect_state == USBD_CDC_CONNECT_STATE_DISCONNECTED
- || ((cdc->tx_buf_ptr_in + 1) & (USBD_CDC_TX_DATA_SIZE - 1)) == cdc->tx_buf_ptr_out) {
+ while (cdc->connect_state == USBD_CDC_CONNECT_STATE_DISCONNECTED || usbd_cdc_tx_buffer_full(cdc)) {
usbd_cdc_try_tx(cdc);
// Wraparound of tick is taken care of by 2's complement arithmetic.
if (HAL_GetTick() - start >= timeout) {
@@ -333,8 +353,7 @@ int usbd_cdc_tx(usbd_cdc_itf_t *cdc, const uint8_t *buf, uint32_t len, uint32_t
}
// Write data to device buffer
- cdc->tx_buf[cdc->tx_buf_ptr_in] = buf[i];
- cdc->tx_buf_ptr_in = (cdc->tx_buf_ptr_in + 1) & (USBD_CDC_TX_DATA_SIZE - 1);
+ usbd_cdc_tx_buffer_put(cdc, buf[i]);
}
usbd_cdc_try_tx(cdc);
@@ -357,7 +376,7 @@ void usbd_cdc_tx_always(usbd_cdc_itf_t *cdc, const uint8_t *buf, uint32_t len) {
// If the buffer is full, wait until it gets drained, with a timeout of 500ms
// (wraparound of tick is taken care of by 2's complement arithmetic).
uint32_t start = HAL_GetTick();
- while (((cdc->tx_buf_ptr_in + 1) & (USBD_CDC_TX_DATA_SIZE - 1)) == cdc->tx_buf_ptr_out && HAL_GetTick() - start <= 500) {
+ while (usbd_cdc_tx_buffer_full(cdc) && HAL_GetTick() - start <= 500) {
usbd_cdc_try_tx(cdc);
if (query_irq() == IRQ_STATE_DISABLED) {
// IRQs disabled so buffer will never be drained; exit loop
@@ -367,8 +386,7 @@ void usbd_cdc_tx_always(usbd_cdc_itf_t *cdc, const uint8_t *buf, uint32_t len) {
}
}
- cdc->tx_buf[cdc->tx_buf_ptr_in] = buf[i];
- cdc->tx_buf_ptr_in = (cdc->tx_buf_ptr_in + 1) & (USBD_CDC_TX_DATA_SIZE - 1);
+ usbd_cdc_tx_buffer_put(cdc, buf[i]);
}
usbd_cdc_try_tx(cdc);
}
diff --git a/ports/stm32/usbd_cdc_interface.h b/ports/stm32/usbd_cdc_interface.h
index 1847b3a6b..d0509b09f 100644
--- a/ports/stm32/usbd_cdc_interface.h
+++ b/ports/stm32/usbd_cdc_interface.h
@@ -35,7 +35,7 @@
#define USBD_CDC_RX_DATA_SIZE (1024) // this must be 2 or greater, and a power of 2
#endif
#ifndef USBD_CDC_TX_DATA_SIZE
-#define USBD_CDC_TX_DATA_SIZE (1024) // I think this can be any value (was 2048)
+#define USBD_CDC_TX_DATA_SIZE (1024) // This must be a power of 2 and no greater than 16384
#endif
// Values for connect_state
@@ -60,7 +60,7 @@ typedef struct _usbd_cdc_itf_t {
uint8_t tx_buf[USBD_CDC_TX_DATA_SIZE]; // data for USB IN endpoind is stored in this buffer
uint16_t tx_buf_ptr_in; // increment this pointer modulo USBD_CDC_TX_DATA_SIZE when new data is available
volatile uint16_t tx_buf_ptr_out; // increment this pointer modulo USBD_CDC_TX_DATA_SIZE when data is drained
- uint16_t tx_buf_ptr_out_shadow; // shadow of above
+ uint16_t tx_buf_ptr_out_next; // next position of above once transmission finished
uint8_t tx_need_empty_packet; // used to flush the USB IN endpoint if the last packet was exactly the endpoint packet size
volatile uint8_t connect_state; // indicates if we are connected
generated by cgit v1.2.3 (git 2.46.0) at 2025-08-28 16:50:46 +0000