TTY/Serial driver fixes for 6.0-rc7

Here are some small, and late, serial driver fixes for 6.0-rc7 to
 resolve some reported problems.
 
 Included in here are:
 	- tegra icount accounting fixes, including a framework function
 	  that other drivers will be converted over to using in 6.1-rc1.
 	- fsl_lpuart reset bugfix
 	- 8250 omap 485 bugfix
 	- sifive serial clock bugfix
 
 The last 3 patches have not shown up in linux-next due to them being
 added to my tree only 2 days ago, but they are tiny and self-contained
 and the developers say they resolve issues that they have with 6.0-rc.
 The other 3 have been in linux-next for a while with no reported issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 -----BEGIN PGP SIGNATURE-----
 
 iG0EABECAC0WIQT0tgzFv3jCIUoxPcsxR9QN2y37KQUCYy6+Tg8cZ3JlZ0Brcm9h
 aC5jb20ACgkQMUfUDdst+yl31wCfSm1SDCziRBj3FuNX4nA7STcn/Q4AnAoyI/wW
 pjm7ZbpcxH8N3CzTAO/n
 =JRNq
 -----END PGP SIGNATURE-----

Merge tag 'tty-6.0-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver fixes from Greg KH:
 "Here are some small, and late, serial driver fixes for 6.0-rc7 to
  resolve some reported problems.

  Included in here are:

   - tegra icount accounting fixes, including a framework function that
     other drivers will be converted over to using in 6.1-rc1.

   - fsl_lpuart reset bugfix

   - 8250 omap 485 bugfix

   - sifive serial clock bugfix

  The last three patches have not shown up in linux-next due to them
  being added to my tree only 2 days ago, but they are tiny and
  self-contained and the developers say they resolve issues that they
  have with 6.0-rc. The other three have been in linux-next for a while
  with no reported issues"

* tag 'tty-6.0-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: sifive: enable clocks for UART when probed
  serial: 8250: omap: Use serial8250_em485_supported
  serial: fsl_lpuart: Reset prior to registration
  serial: tegra-tcu: Use uart_xmit_advance(), fixes icount.tx accounting
  serial: tegra: Use uart_xmit_advance(), fixes icount.tx accounting
  serial: Create uart_xmit_advance()

drivers/tty/serial/8250/8250_omap.c

@@ -1334,6 +1334,7 @@ static int omap8250_probe(struct platform_device *pdev)
 	up.port.throttle = omap_8250_throttle;
 	up.port.unthrottle = omap_8250_unthrottle;
 	up.port.rs485_config = serial8250_em485_config;
+	up.port.rs485_supported = serial8250_em485_supported;
 	up.rs485_start_tx = serial8250_em485_start_tx;
 	up.rs485_stop_tx = serial8250_em485_stop_tx;
 	up.port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);

drivers/tty/serial/fsl_lpuart.c

@@ -2724,14 +2724,15 @@ static int lpuart_probe(struct platform_device *pdev)
 		lpuart_reg.cons = LPUART_CONSOLE;
 		handler = lpuart_int;
 	}
-	ret = uart_add_one_port(&lpuart_reg, &sport->port);
-	if (ret)
-		goto failed_attach_port;
 
 	ret = lpuart_global_reset(sport);
 	if (ret)
 		goto failed_reset;
 
+	ret = uart_add_one_port(&lpuart_reg, &sport->port);
+	if (ret)
+		goto failed_attach_port;
+
 	ret = uart_get_rs485_mode(&sport->port);
 	if (ret)
 		goto failed_get_rs485;
@@ -2747,9 +2748,9 @@ static int lpuart_probe(struct platform_device *pdev)
 
 failed_irq_request:
 failed_get_rs485:
-failed_reset:
 	uart_remove_one_port(&lpuart_reg, &sport->port);
 failed_attach_port:
+failed_reset:
 	lpuart_disable_clks(sport);
 	return ret;
 }

drivers/tty/serial/serial-tegra.c

@@ -525,7 +525,7 @@ static void tegra_uart_tx_dma_complete(void *args)
 	count = tup->tx_bytes_requested - state.residue;
 	async_tx_ack(tup->tx_dma_desc);
 	spin_lock_irqsave(&tup->uport.lock, flags);
-	xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
+	uart_xmit_advance(&tup->uport, count);
 	tup->tx_in_progress = 0;
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(&tup->uport);
@@ -613,7 +613,6 @@ static unsigned int tegra_uart_tx_empty(struct uart_port *u)
 static void tegra_uart_stop_tx(struct uart_port *u)
 {
 	struct tegra_uart_port *tup = to_tegra_uport(u);
-	struct circ_buf *xmit = &tup->uport.state->xmit;
 	struct dma_tx_state state;
 	unsigned int count;
 
@@ -624,7 +623,7 @@ static void tegra_uart_stop_tx(struct uart_port *u)
 	dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
 	count = tup->tx_bytes_requested - state.residue;
 	async_tx_ack(tup->tx_dma_desc);
-	xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
+	uart_xmit_advance(&tup->uport, count);
 	tup->tx_in_progress = 0;
 }
 

drivers/tty/serial/sifive.c

@@ -945,7 +945,7 @@ static int sifive_serial_probe(struct platform_device *pdev)
 		return PTR_ERR(base);
 	}
 
-	clk = devm_clk_get(&pdev->dev, NULL);
+	clk = devm_clk_get_enabled(&pdev->dev, NULL);
 	if (IS_ERR(clk)) {
 		dev_err(&pdev->dev, "unable to find controller clock\n");
 		return PTR_ERR(clk);

drivers/tty/serial/tegra-tcu.c

@@ -101,7 +101,7 @@ static void tegra_tcu_uart_start_tx(struct uart_port *port)
 			break;
 
 		tegra_tcu_write(tcu, &xmit->buf[xmit->tail], count);
-		xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
+		uart_xmit_advance(port, count);
 	}
 
 	uart_write_wakeup(port);

include/linux/serial_core.h

@@ -624,6 +624,23 @@ struct uart_state {
 /* number of characters left in xmit buffer before we ask for more */
 #define WAKEUP_CHARS		256
 
+/**
+ * uart_xmit_advance - Advance xmit buffer and account Tx'ed chars
+ * @up: uart_port structure describing the port
+ * @chars: number of characters sent
+ *
+ * This function advances the tail of circular xmit buffer by the number of
+ * @chars transmitted and handles accounting of transmitted bytes (into
+ * @up's icount.tx).
+ */
+static inline void uart_xmit_advance(struct uart_port *up, unsigned int chars)
+{
+	struct circ_buf *xmit = &up->state->xmit;
+
+	xmit->tail = (xmit->tail + chars) & (UART_XMIT_SIZE - 1);
+	up->icount.tx += chars;
+}
+
 struct module;
 struct tty_driver;