Merge tag 'tty-4.11-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial fixes from Greg KH:
 "Here are some small fixes for some serial drivers and Kconfig help
  text for 4.11-rc5. Nothing major here at all, a few things resolving
  reported bugs in some random serial drivers.

  I don't think these made the last linux-next due to me getting to them
  yesterday, but I am not sure, they might have snuck in. The patches
  only affect drivers that the maintainers of sent me these patches for,
  so we should be safe here :)"

* tag 'tty-4.11-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: pl011: fix earlycon work-around for QDF2400 erratum 44
  serial: 8250_EXAR: fix duplicate Kconfig text and add missing help text
  tty/serial: atmel: fix TX path in atmel_console_write()
  tty/serial: atmel: fix race condition (TX+DMA)
  serial: mxs-auart: Fix baudrate calculation

4 files changed, 36 insertions, 5 deletions

diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index a65fb8197aec..0e3f529d50e9 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -128,9 +128,13 @@ config SERIAL_8250_PCI
 	  by the parport_serial driver, enabled with CONFIG_PARPORT_SERIAL.
 
 config SERIAL_8250_EXAR
-        tristate "8250/16550 PCI device support"
-        depends on SERIAL_8250_PCI
+	tristate "8250/16550 Exar/Commtech PCI/PCIe device support"
+	depends on SERIAL_8250_PCI
 	default SERIAL_8250
+	help
+	  This builds support for XR17C1xx, XR17V3xx and some Commtech
+	  422x PCIe serial cards that are not covered by the more generic
+	  SERIAL_8250_PCI option.
 
 config SERIAL_8250_HP300
 	tristate
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 56f92d7348bf..b0a377725d63 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2452,18 +2452,37 @@ static void pl011_early_write(struct console *con, const char *s, unsigned n)
 	uart_console_write(&dev->port, s, n, pl011_putc);
 }
 
+/*
+ * On non-ACPI systems, earlycon is enabled by specifying
+ * "earlycon=pl011,<address>" on the kernel command line.
+ *
+ * On ACPI ARM64 systems, an "early" console is enabled via the SPCR table,
+ * by specifying only "earlycon" on the command line.  Because it requires
+ * SPCR, the console starts after ACPI is parsed, which is later than a
+ * traditional early console.
+ *
+ * To get the traditional early console that starts before ACPI is parsed,
+ * specify the full "earlycon=pl011,<address>" option.
+ */
 static int __init pl011_early_console_setup(struct earlycon_device *device,
 					    const char *opt)
 {
 	if (!device->port.membase)
 		return -ENODEV;
 
-	device->con->write = qdf2400_e44_present ?
-				qdf2400_e44_early_write : pl011_early_write;
+	/* On QDF2400 SOCs affected by Erratum 44, the "qdf2400_e44" must
+	 * also be specified, e.g. "earlycon=pl011,<address>,qdf2400_e44".
+	 */
+	if (!strcmp(device->options, "qdf2400_e44"))
+		device->con->write = qdf2400_e44_early_write;
+	else
+		device->con->write = pl011_early_write;
+
 	return 0;
 }
 OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup);
 OF_EARLYCON_DECLARE(pl011, "arm,sbsa-uart", pl011_early_console_setup);
+EARLYCON_DECLARE(qdf2400_e44, pl011_early_console_setup);
 
 #else
 #define AMBA_CONSOLE	NULL
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index dcebb28ffbc4..1f50a83ef958 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -1951,6 +1951,11 @@ static void atmel_flush_buffer(struct uart_port *port)
 		atmel_uart_writel(port, ATMEL_PDC_TCR, 0);
 		atmel_port->pdc_tx.ofs = 0;
 	}
+	/*
+	 * in uart_flush_buffer(), the xmit circular buffer has just
+	 * been cleared, so we have to reset tx_len accordingly.
+	 */
+	atmel_port->tx_len = 0;
 }
 
 /*
@@ -2483,6 +2488,9 @@ static void atmel_console_write(struct console *co, const char *s, u_int count)
 	pdc_tx = atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN;
 	atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
 
+	/* Make sure that tx path is actually able to send characters */
+	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN);
+
 	uart_console_write(port, s, count, atmel_console_putchar);
 
 	/*
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 6989b227d134..be94246b6fcc 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -1088,7 +1088,7 @@ static void mxs_auart_settermios(struct uart_port *u,
 					AUART_LINECTRL_BAUD_DIV_MAX);
 		baud_max = u->uartclk * 32 / AUART_LINECTRL_BAUD_DIV_MIN;
 		baud = uart_get_baud_rate(u, termios, old, baud_min, baud_max);
-		div = u->uartclk * 32 / baud;
+		div = DIV_ROUND_CLOSEST(u->uartclk * 32, baud);
 	}
 
 	ctrl |= AUART_LINECTRL_BAUD_DIVFRAC(div & 0x3F);