From 293f8995948330e1df9228519535593618b5ec0e Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Thu, 19 Dec 2019 15:51:09 +0100 Subject: [PATCH] tty: serial: 21285: stop using the unused[] variable from struct uart_port Much like the samsung_tty driver (now I know where they copied the idea from), the 21285 uart driver uses 2 bytes from the "unused" array of struct uart_port to keep tx/rx enabled/disabled state. Those fields are going away (they were never really needed in the first place), so fix up the 21285 driver by another horrible hack. Instead of creating a whole structure for just 2 bytes, just use two bits from the private_data pointer instead, as that pointer is never used. The two bits reflect if tx/rx is now enabled/disabled. Astute readers will note that once rx is disabled, nothing ever seems to turn it back on, making one wonder if anyone has ever done this. Reported-by: kbuild test robot Cc: Dmitry Safonov Cc: Russell King Cc: Jiri Slaby Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Link: https://lore.kernel.org/r/20191219145109.GA1962496@kroah.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/21285.c | 55 +++++++++++++++++++++++++++++++++++++--------- 1 file changed, 45 insertions(+), 10 deletions(-) diff --git a/drivers/tty/serial/21285.c b/drivers/tty/serial/21285.c index 32b3acf..718e010 100644 --- a/drivers/tty/serial/21285.c +++ b/drivers/tty/serial/21285.c @@ -41,8 +41,43 @@ static const char serial21285_name[] = "Footbridge UART"; -#define tx_enabled(port) ((port)->unused[0]) -#define rx_enabled(port) ((port)->unused[1]) +/* + * We only need 2 bits of data, so instead of creating a whole structure for + * this, use bits of the private_data pointer of the uart port structure. + */ +#define tx_enabled_bit 0 +#define rx_enabled_bit 1 + +static bool is_enabled(struct uart_port *port, int bit) +{ + unsigned long private_data = (unsigned long)port->private_data; + + if (test_bit(bit, &private_data)) + return true; + return false; +} + +static void enable(struct uart_port *port, int bit) +{ + unsigned long private_data = (unsigned long)port->private_data; + + set_bit(bit, &private_data); +} + +static void disable(struct uart_port *port, int bit) +{ + unsigned long private_data = (unsigned long)port->private_data; + + clear_bit(bit, &private_data); +} + +#define is_tx_enabled(port) is_enabled(port, tx_enabled_bit) +#define tx_enable(port) enable(port, tx_enabled_bit) +#define tx_disable(port) disable(port, tx_enabled_bit) + +#define is_rx_enabled(port) is_enabled(port, rx_enabled_bit) +#define rx_enable(port) enable(port, rx_enabled_bit) +#define rx_disable(port) disable(port, rx_enabled_bit) /* * The documented expression for selecting the divisor is: @@ -57,25 +92,25 @@ static const char serial21285_name[] = "Footbridge UART"; static void serial21285_stop_tx(struct uart_port *port) { - if (tx_enabled(port)) { + if (is_tx_enabled(port)) { disable_irq_nosync(IRQ_CONTX); - tx_enabled(port) = 0; + tx_disable(port); } } static void serial21285_start_tx(struct uart_port *port) { - if (!tx_enabled(port)) { + if (!is_tx_enabled(port)) { enable_irq(IRQ_CONTX); - tx_enabled(port) = 1; + tx_enable(port); } } static void serial21285_stop_rx(struct uart_port *port) { - if (rx_enabled(port)) { + if (is_rx_enabled(port)) { disable_irq_nosync(IRQ_CONRX); - rx_enabled(port) = 0; + rx_disable(port); } } @@ -185,8 +220,8 @@ static int serial21285_startup(struct uart_port *port) { int ret; - tx_enabled(port) = 1; - rx_enabled(port) = 1; + tx_enable(port); + rx_enable(port); ret = request_irq(IRQ_CONRX, serial21285_rx_chars, 0, serial21285_name, port); -- 2.7.4