mehrdadh commented on a change in pull request #8021:
URL: https://github.com/apache/tvm/pull/8021#discussion_r641831869
##########
File path: apps/microtvm/zephyr/host_driven/src/main.c
##########
@@ -214,33 +216,37 @@ tvm_crt_error_t TVMPlatformTimerStop(double*
elapsed_time_seconds) {
}
// Ring buffer used to store data read from the UART on rx interrupt.
-#define RING_BUF_SIZE_BYTES 4 * 1024
-RING_BUF_DECLARE(uart_rx_rbuf, RING_BUF_SIZE_BYTES);
-
-// Small buffer used to read data from the UART into the ring buffer.
-static uint8_t uart_data[8];
+// TODO(mehrdadh): Explore why offset is required.
+#define RING_BUF_SIZE_BYTES (TVM_CRT_MAX_PACKET_SIZE_BYTES + 100)
+RING_BUF_ITEM_DECLARE_SIZE(uart_rx_rbuf, RING_BUF_SIZE_BYTES);
// UART interrupt callback.
void uart_irq_cb(const struct device* dev, void* user_data) {
- while (uart_irq_update(dev) && uart_irq_is_pending(dev)) {
+ uart_irq_update(dev);
+ if (uart_irq_is_pending(dev)) {
struct ring_buf* rbuf = (struct ring_buf*)user_data;
if (uart_irq_rx_ready(dev) != 0) {
- for (;;) {
- // Read a small chunk of data from the UART.
- int bytes_read = uart_fifo_read(dev, uart_data, sizeof(uart_data));
- if (bytes_read < 0) {
- TVMPlatformAbort((tvm_crt_error_t)0xbeef1);
- } else if (bytes_read == 0) {
- break;
- }
- // Write it into the ring buffer.
- int bytes_written = ring_buf_put(rbuf, uart_data, bytes_read);
- if (bytes_read != bytes_written) {
- TVMPlatformAbort((tvm_crt_error_t)0xbeef2);
- }
- // CHECK_EQ(bytes_read, bytes_written, "bytes_read: %d; bytes_written:
%d", bytes_read,
- // bytes_written);
+ uint8_t* data;
+ uint32_t size;
+ size = ring_buf_put_claim(rbuf, &data, RING_BUF_SIZE_BYTES);
Review comment:
This is because in this case we don't need to use an intermediate buffer
and we can read/write directly from/to the ring buffer. This is specially
important for reading from ring buffer, because before this we had to allocate
an extra array and do extra an extra copy of a large array.
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