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authorPali Rohár <pali@kernel.org>2022-06-28 13:09:22 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-07-29 18:14:09 +0300
commitc68f6e2e4fda5f36d403f64fa57a2804ec59a87d (patch)
tree6c6a43eede2de3f4824bf581cf3e3cae55dec62f /drivers
parent2230428fb866cb2a7a62e35b7aedfd43d3afa797 (diff)
downloadlinux-c68f6e2e4fda5f36d403f64fa57a2804ec59a87d.tar.xz
serial: mvebu-uart: correctly report configured baudrate value
commit 4f532c1e25319e42996ec18a1f473fd50c8e575d upstream. 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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/tty/serial/mvebu-uart.c25
1 files changed, 13 insertions, 12 deletions
diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
index 13db15118cb9..2ce0d05be368 100644
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -443,13 +443,13 @@ static void mvebu_uart_shutdown(struct uart_port *port)
}
}
-static int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
+static unsigned int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
{
unsigned int d_divisor, m_divisor;
u32 brdv, osamp;
if (!port->uartclk)
- return -EOPNOTSUPP;
+ return 0;
/*
* The baudrate is derived from the UART clock thanks to two divisors:
@@ -473,7 +473,7 @@ static int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
osamp &= ~OSAMP_DIVISORS_MASK;
writel(osamp, port->membase + UART_OSAMP);
- return 0;
+ return DIV_ROUND_CLOSEST(port->uartclk, d_divisor * m_divisor);
}
static void mvebu_uart_set_termios(struct uart_port *port,
@@ -510,15 +510,11 @@ static void mvebu_uart_set_termios(struct uart_port *port,
max_baud = 230400;
baud = uart_get_baud_rate(port, termios, old, min_baud, max_baud);
- if (mvebu_uart_baud_rate_set(port, baud)) {
- /* No clock available, baudrate cannot be changed */
- if (old)
- baud = uart_get_baud_rate(port, old, NULL,
- min_baud, max_baud);
- } else {
- tty_termios_encode_baud_rate(termios, baud, baud);
- uart_update_timeout(port, termios->c_cflag, baud);
- }
+ baud = mvebu_uart_baud_rate_set(port, baud);
+
+ /* In case baudrate cannot be changed, report previous old value */
+ if (baud == 0 && old)
+ baud = tty_termios_baud_rate(old);
/* Only the following flag changes are supported */
if (old) {
@@ -529,6 +525,11 @@ static void mvebu_uart_set_termios(struct uart_port *port,
termios->c_cflag |= CS8;
}
+ if (baud != 0) {
+ tty_termios_encode_baud_rate(termios, baud, baud);
+ uart_update_timeout(port, termios->c_cflag, baud);
+ }
+
spin_unlock_irqrestore(&port->lock, flags);
}