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drivers: serial: emul: Make UART FIFO size realistic

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Real UARTs usually write 1 to a few bytes at a time through a
latch buffer. Add latch buffer property to binding for
uart_emul and limit fifo_read and fifo_fill to not exceed the
latch buffer.

Signed-off-by: Bjarki Arge Andreasen <bjarkix123@gmail.com>
This commit is contained in:
Bjarki Arge Andreasen 2023-11-02 17:31:05 +01:00 • committed by Carles Cufí
commit 27dfdd737e
2 changed files with 16 additions and 10 deletions
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20
drivers/serial/uart_emul.c
View file

@ -19,6 +19,7 @@ LOG_MODULE_REGISTER(uart_emul, CONFIG_UART_LOG_LEVEL);
struct uart_emul_config {
bool loopback;
size_t latch_buffer_size;
};
struct uart_emul_work {
@ -147,13 +148,14 @@ static int uart_emul_fifo_fill(const struct device *dev, const uint8_t *tx_data,
int ret;
struct uart_emul_data *data = dev->data;
const struct uart_emul_config *config = dev->config;
uint32_t put_size = MIN(config->latch_buffer_size, size);
K_SPINLOCK(&data->tx_lock) {
ret = ring_buf_put(data->tx_rb, tx_data, size);
ret = ring_buf_put(data->tx_rb, tx_data, put_size);
}
if (config->loopback) {
uart_emul_put_rx_data(dev, (uint8_t *)tx_data, ret);
uart_emul_put_rx_data(dev, (uint8_t *)tx_data, put_size);
}
if (data->tx_data_ready_cb) {
data->tx_data_ready_cb(dev, ring_buf_size_get(data->tx_rb), data->user_data);
@ -164,19 +166,16 @@ static int uart_emul_fifo_fill(const struct device *dev, const uint8_t *tx_data,
static int uart_emul_fifo_read(const struct device *dev, uint8_t *rx_data, int size)
{
int ret;
struct uart_emul_data *data = dev->data;
const struct uart_emul_config *config = dev->config;
uint32_t bytes_to_read;
K_SPINLOCK(&data->rx_lock) {
ret = MIN(size, ring_buf_size_get(data->rx_rb));
size = ret;
for (int n = 0; size > 0; size -= n, rx_data += n) {
n = ring_buf_get(data->rx_rb, rx_data, size);
}
bytes_to_read = MIN(config->latch_buffer_size, ring_buf_size_get(data->rx_rb));
ring_buf_get(data->rx_rb, rx_data, bytes_to_read);
}
return ret;
return bytes_to_read;
}
static int uart_emul_irq_tx_ready(const struct device *dev)
@ -450,6 +449,7 @@ void uart_emul_set_errors(const struct device *dev, int errors)
\
static struct uart_emul_config uart_emul_cfg_##inst = { \
.loopback = DT_INST_PROP(inst, loopback), \
.latch_buffer_size = DT_INST_PROP(inst, latch_buffer_size), \
}; \
static struct uart_emul_data uart_emul_data_##inst = { \
.rx_rb = &uart_emul_##inst##_rx_rb, \

6
dts/bindings/serial/zephyr,uart-emul.yaml
View file

@ -25,3 +25,9 @@ properties:
description: |
Connects TX to RX internally creating a loop back connection. Useful
for testing.
latch-buffer-size:
type: int
default: 1
description: |
Size of the virtual UART latch buffer.