Merge tag 'tty-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver updates from Greg KH:
 "Here is the "big" set of tty/serial driver changes for 6.2-rc1.

  As in previous kernel releases, nothing big here at all, just some
  small incremental serial/tty layer cleanups and some individual driver
  additions and fixes. Highlights are:

   - serial helper macros from Jiri Slaby to reduce the amount of
     duplicated code in serial drivers

   - api cleanups and consolidations from Ilpo Järvinen in lots of
     serial drivers

   - the usual set of n_gsm fixes from Daniel Starke as that code gets
     exercised more

   - TIOCSTI is finally able to be disabled if requested (security
     hardening feature from Kees Cook)

   - fsl_lpuart driver fixes and features added

   - other small serial driver additions and fixes

  All of these have been in linux-next for a while with no reported
  problems"

* tag 'tty-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (97 commits)
  serial: atmel: don't stop the transmitter when doing PIO
  serial: atmel: cleanup atmel_start+stop_tx()
  tty: serial: fsl_lpuart: switch to new dmaengine_terminate_* API
  serial: sunsab: Fix error handling in sunsab_init()
  serial: altera_uart: fix locking in polling mode
  serial: pch: Fix PCI device refcount leak in pch_request_dma()
  tty: serial: fsl_lpuart: Use pm_ptr() to avoid need to make pm __maybe_unused
  tty: serial: fsl_lpuart: Add runtime pm support
  tty: serial: fsl_lpuart: enable wakeup source for lpuart
  serdev: Replace poll loop by readx_poll_timeout() macro
  tty: synclink_gt: unwind actions in error path of net device open
  serial: stm32: move dma_request_chan() before clk_prepare_enable()
  dt-bindings: serial: xlnx,opb-uartlite: Drop 'contains' from 'xlnx,use-parity'
  serial: pl011: Do not clear RX FIFO & RX interrupt in unthrottle.
  serial: amba-pl011: avoid SBSA UART accessing DMACR register
  tty: serial: altera_jtaguart: remove struct altera_jtaguart
  tty: serial: altera_jtaguart: use uart_port::read_status_mask
  tty: serial: altera_jtaguart: remove unused altera_jtaguart::sigs
  tty: serial: altera_jtaguart: remove flag from altera_jtaguart_rx_chars()
  n_tty: Rename tail to old_tail in n_tty_read()
  ...

include/linux/serdev.h

@@ -7,6 +7,7 @@
 
 #include <linux/types.h>
 #include <linux/device.h>
+#include <linux/iopoll.h>
 #include <linux/uaccess.h>
 #include <linux/termios.h>
 #include <linux/delay.h>
@@ -279,18 +280,10 @@ static inline bool serdev_device_get_cts(struct serdev_device *serdev)
 
 static inline int serdev_device_wait_for_cts(struct serdev_device *serdev, bool state, int timeout_ms)
 {
-	unsigned long timeout;
 	bool signal;
 
-	timeout = jiffies + msecs_to_jiffies(timeout_ms);
-	while (time_is_after_jiffies(timeout)) {
-		signal = serdev_device_get_cts(serdev);
-		if (signal == state)
-			return 0;
-		usleep_range(1000, 2000);
-	}
-
-	return -ETIMEDOUT;
+	return readx_poll_timeout(serdev_device_get_cts, serdev, signal, signal == state,
+				  2000, timeout_ms * 1000);
 }
 
 static inline int serdev_device_set_rts(struct serdev_device *serdev, bool enable)

include/linux/serial_core.h

@@ -664,6 +664,86 @@ struct uart_driver {
 
 void uart_write_wakeup(struct uart_port *port);
 
+#define __uart_port_tx(uport, ch, tx_ready, put_char, tx_done, for_test,      \
+		for_post)						      \
+({									      \
+	struct uart_port *__port = (uport);				      \
+	struct circ_buf *xmit = &__port->state->xmit;			      \
+	unsigned int pending;						      \
+									      \
+	for (; (for_test) && (tx_ready); (for_post), __port->icount.tx++) {   \
+		if (__port->x_char) {					      \
+			(ch) = __port->x_char;				      \
+			(put_char);					      \
+			__port->x_char = 0;				      \
+			continue;					      \
+		}							      \
+									      \
+		if (uart_circ_empty(xmit) || uart_tx_stopped(__port))	      \
+			break;						      \
+									      \
+		(ch) = xmit->buf[xmit->tail];				      \
+		(put_char);						      \
+		xmit->tail = (xmit->tail + 1) % UART_XMIT_SIZE;		      \
+	}								      \
+									      \
+	(tx_done);							      \
+									      \
+	pending = uart_circ_chars_pending(xmit);			      \
+	if (pending < WAKEUP_CHARS) {					      \
+		uart_write_wakeup(__port);				      \
+									      \
+		if (pending == 0)					      \
+			__port->ops->stop_tx(__port);			      \
+	}								      \
+									      \
+	pending;							      \
+})
+
+/**
+ * uart_port_tx_limited -- transmit helper for uart_port with count limiting
+ * @port: uart port
+ * @ch: variable to store a character to be written to the HW
+ * @count: a limit of characters to send
+ * @tx_ready: can HW accept more data function
+ * @put_char: function to write a character
+ * @tx_done: function to call after the loop is done
+ *
+ * This helper transmits characters from the xmit buffer to the hardware using
+ * @put_char(). It does so until @count characters are sent and while @tx_ready
+ * evaluates to true.
+ *
+ * Returns: the number of characters in the xmit buffer when done.
+ *
+ * The expression in macro parameters shall be designed as follows:
+ *  * **tx_ready:** should evaluate to true if the HW can accept more data to
+ *    be sent. This parameter can be %true, which means the HW is always ready.
+ *  * **put_char:** shall write @ch to the device of @port.
+ *  * **tx_done:** when the write loop is done, this can perform arbitrary
+ *    action before potential invocation of ops->stop_tx() happens. If the
+ *    driver does not need to do anything, use e.g. ({}).
+ *
+ * For all of them, @port->lock is held, interrupts are locally disabled and
+ * the expressions must not sleep.
+ */
+#define uart_port_tx_limited(port, ch, count, tx_ready, put_char, tx_done) ({ \
+	unsigned int __count = (count);					      \
+	__uart_port_tx(port, ch, tx_ready, put_char, tx_done, __count,	      \
+			__count--);					      \
+})
+
+/**
+ * uart_port_tx -- transmit helper for uart_port
+ * @port: uart port
+ * @ch: variable to store a character to be written to the HW
+ * @tx_ready: can HW accept more data function
+ * @put_char: function to write a character
+ *
+ * See uart_port_tx_limited() for more details.
+ */
+#define uart_port_tx(port, ch, tx_ready, put_char)			\
+	__uart_port_tx(port, ch, tx_ready, put_char, ({}), true, ({}))
+
 /*
  * Baud rate helpers.
  */

include/linux/tty_buffer.h

@@ -17,14 +17,11 @@ struct tty_buffer {
 	int commit;
 	int lookahead;		/* Lazy update on recv, can become less than "read" */
 	int read;
-	int flags;
+	bool flags;
 	/* Data points here */
 	unsigned long data[];
 };
 
-/* Values for .flags field of tty_buffer */
-#define TTYB_NORMAL	1	/* buffer has no flags buffer */
-
 static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs)
 {
 	return ((unsigned char *)b->data) + ofs;

include/linux/tty_flip.h

@@ -25,9 +25,9 @@ static inline int tty_insert_flip_char(struct tty_port *port,
 	struct tty_buffer *tb = port->buf.tail;
 	int change;
 
-	change = (tb->flags & TTYB_NORMAL) && (flag != TTY_NORMAL);
+	change = !tb->flags && (flag != TTY_NORMAL);
 	if (!change && tb->used < tb->size) {
-		if (~tb->flags & TTYB_NORMAL)
+		if (tb->flags)
 			*flag_buf_ptr(tb, tb->used) = flag;
 		*char_buf_ptr(tb, tb->used++) = ch;
 		return 1;