Messages in this thread | | | From | Muni Sekhar <> | Date | Thu, 3 May 2018 20:08:48 +0530 | Subject | serial: start_tx & buffer handling |
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Hi All,
I’m trying to understand how user mode buffer is written to low level serial hardware registers.
For this I read the kernel code and I came to know that from user mode write() API lands into kernel’s tty_write() ("drivers/tty/tty_io.c") and then it calls a uart_write() ("drivers/tty/serial/serial_core.c").
In uart_write(), the buffer is copied to circ_buf and then it calls low level serial hardware driver’s start_tx() (struct uart_ops .start_tx). But here I could not find how the buffer kept in circ_buf is copied to serial port’s TX_FIFO registers?
Can someone take a moment to explain me on this?
-- Thanks, Sekhar
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