serial: mvebu-uart: correctly report configured baudrate value
Functions tty_termios_encode_baud_rate() and uart_update_timeout() should be called with the baudrate value which was set to hardware. Linux then report exact values via ioctl(TCGETS2) to userspace. Change mvebu_uart_baud_rate_set() function to return baudrate value which was set to hardware and propagate this value to above mentioned functions. With this change userspace would see precise value in termios c_ospeed field. Fixes: 68a0db1d7da2 ("serial: mvebu-uart: add function to change baudrate") Cc: stable <stable@kernel.org> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Pali Rohár <pali@kernel.org> Link: https://lore.kernel.org/r/20220628100922.10717-1-pali@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -470,14 +470,14 @@ static void mvebu_uart_shutdown(struct uart_port *port)
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}
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}
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static int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
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static unsigned int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
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{
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unsigned int d_divisor, m_divisor;
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unsigned long flags;
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u32 brdv, osamp;
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if (!port->uartclk)
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return -EOPNOTSUPP;
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return 0;
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/*
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* The baudrate is derived from the UART clock thanks to divisors:
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@ -548,7 +548,7 @@ static int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
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(m_divisor << 16) | (m_divisor << 24);
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writel(osamp, port->membase + UART_OSAMP);
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return 0;
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return DIV_ROUND_CLOSEST(port->uartclk, d_divisor * m_divisor);
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}
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static void mvebu_uart_set_termios(struct uart_port *port,
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@ -587,15 +587,11 @@ static void mvebu_uart_set_termios(struct uart_port *port,
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max_baud = port->uartclk / 80;
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baud = uart_get_baud_rate(port, termios, old, min_baud, max_baud);
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if (mvebu_uart_baud_rate_set(port, baud)) {
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/* No clock available, baudrate cannot be changed */
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if (old)
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baud = uart_get_baud_rate(port, old, NULL,
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min_baud, max_baud);
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} else {
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tty_termios_encode_baud_rate(termios, baud, baud);
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uart_update_timeout(port, termios->c_cflag, baud);
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}
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baud = mvebu_uart_baud_rate_set(port, baud);
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/* In case baudrate cannot be changed, report previous old value */
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if (baud == 0 && old)
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baud = tty_termios_baud_rate(old);
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/* Only the following flag changes are supported */
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if (old) {
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@ -606,6 +602,11 @@ static void mvebu_uart_set_termios(struct uart_port *port,
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termios->c_cflag |= CS8;
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}
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if (baud != 0) {
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tty_termios_encode_baud_rate(termios, baud, baud);
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uart_update_timeout(port, termios->c_cflag, baud);
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}
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spin_unlock_irqrestore(&port->lock, flags);
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}
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