1 files changed, 37 insertions, 17 deletions

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index b0a377725d63..8a857bb34fbb 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -1327,14 +1327,15 @@ static void pl011_stop_tx(struct uart_port *port)
 	pl011_dma_tx_stop(uap);
 }
 
-static void pl011_tx_chars(struct uart_amba_port *uap, bool from_irq);
+static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq);
 
 /* Start TX with programmed I/O only (no DMA) */
 static void pl011_start_tx_pio(struct uart_amba_port *uap)
 {
-	uap->im |= UART011_TXIM;
-	pl011_write(uap->im, uap, REG_IMSC);
-	pl011_tx_chars(uap, false);
+	if (pl011_tx_chars(uap, false)) {
+		uap->im |= UART011_TXIM;
+		pl011_write(uap->im, uap, REG_IMSC);
+	}
 }
 
 static void pl011_start_tx(struct uart_port *port)
@@ -1414,25 +1415,26 @@ static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c,
 	return true;
 }
 
-static void pl011_tx_chars(struct uart_amba_port *uap, bool from_irq)
+/* Returns true if tx interrupts have to be (kept) enabled  */
+static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq)
 {
 	struct circ_buf *xmit = &uap->port.state->xmit;
 	int count = uap->fifosize >> 1;
 
 	if (uap->port.x_char) {
 		if (!pl011_tx_char(uap, uap->port.x_char, from_irq))
-			return;
+			return true;
 		uap->port.x_char = 0;
 		--count;
 	}
 	if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
 		pl011_stop_tx(&uap->port);
-		return;
+		return false;
 	}
 
 	/* If we are using DMA mode, try to send some characters. */
 	if (pl011_dma_tx_irq(uap))
-		return;
+		return true;
 
 	do {
 		if (likely(from_irq) && count-- == 0)
@@ -1447,8 +1449,11 @@ static void pl011_tx_chars(struct uart_amba_port *uap, bool from_irq)
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(&uap->port);
 
-	if (uart_circ_empty(xmit))
+	if (uart_circ_empty(xmit)) {
 		pl011_stop_tx(&uap->port);
+		return false;
+	}
+	return true;
 }
 
 static void pl011_modem_status(struct uart_amba_port *uap)
@@ -2470,19 +2475,34 @@ static int __init pl011_early_console_setup(struct earlycon_device *device,
 	if (!device->port.membase)
 		return -ENODEV;
 
-	/* 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;
+	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);
+
+/*
+ * On Qualcomm Datacenter Technologies QDF2400 SOCs affected by
+ * Erratum 44, traditional earlycon can be enabled by specifying
+ * "earlycon=qdf2400_e44,<address>".  Any options are ignored.
+ *
+ * Alternatively, you can just specify "earlycon", and the early console
+ * will be enabled with the information from the SPCR table.  In this
+ * case, the SPCR code will detect the need for the E44 work-around,
+ * and set the console name to "qdf2400_e44".
+ */
+static int __init
+qdf2400_e44_early_console_setup(struct earlycon_device *device,
+				const char *opt)
+{
+	if (!device->port.membase)
+		return -ENODEV;
+
+	device->con->write = qdf2400_e44_early_write;
+	return 0;
+}
+EARLYCON_DECLARE(qdf2400_e44, qdf2400_e44_early_console_setup);
 
 #else
 #define AMBA_CONSOLE	NULL