UART_FIFO_REG
bcm_uart0_writel(c, UART_FIFO_REG);
cstat = c = bcm_uart_readl(port, UART_FIFO_REG);
bcm_uart_writel(port, ch, UART_FIFO_REG),
(void)bcm_uart_readl(port, UART_FIFO_REG);
return bcm_uart_readl(port, UART_FIFO_REG);
bcm_uart_writel(port, c, UART_FIFO_REG);
bcm_uart_writel(port, ch, UART_FIFO_REG);
u32 rx = esp32_uart_read(port, UART_FIFO_REG);
esp32_uart_write(port, UART_FIFO_REG, c);
return esp32_uart_read(port, UART_FIFO_REG);