linux-kernel - [PATCH 2/4] serial: uartps: Use dynamic array for console port

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Date:   Mon, 23 Apr 2018 11:51:01 +0200
From:   Michal Simek <michal.simek@...inx.com>
To:     linux-kernel@...r.kernel.org, monstr@...str.eu,
        Alan Cox <gnomes@...rguk.ukuu.org.uk>, geert+renesas@...der.be
Cc:     Jiri Slaby <jslaby@...e.com>, linux-serial@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH 2/4] serial: uartps: Use dynamic array for console port

Driver console functions are using pointer to static array with fixed
size. There can be only one serial console at the time which is found
by register_console(). register_console() is filling cons->index to
port->line value.

Signed-off-by: Michal Simek <michal.simek@...inx.com>
Reviewed-by: Alan Cox <alan@...ux.intel.com>
---

 drivers/tty/serial/xilinx_uartps.c | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 932210331484..789423d081ed 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1206,6 +1206,10 @@ OF_EARLYCON_DECLARE(cdns, "cdns,uart-r1p8", cdns_early_console_setup);
 OF_EARLYCON_DECLARE(cdns, "cdns,uart-r1p12", cdns_early_console_setup);
 OF_EARLYCON_DECLARE(cdns, "xlnx,zynqmp-uart", cdns_early_console_setup);
 
+
+/* Static pointer to console port */
+static struct uart_port *console_port;
+
 /**
  * cdns_uart_console_write - perform write operation
  * @co: Console handle
@@ -1215,7 +1219,7 @@ OF_EARLYCON_DECLARE(cdns, "xlnx,zynqmp-uart", cdns_early_console_setup);
 static void cdns_uart_console_write(struct console *co, const char *s,
 				unsigned int count)
 {
-	struct uart_port *port = &cdns_uart_port[co->index];
+	struct uart_port *port = console_port;
 	unsigned long flags;
 	unsigned int imr, ctrl;
 	int locked = 1;
@@ -1261,15 +1265,13 @@ static void cdns_uart_console_write(struct console *co, const char *s,
  */
 static int __init cdns_uart_console_setup(struct console *co, char *options)
 {
-	struct uart_port *port = &cdns_uart_port[co->index];
+	struct uart_port *port = console_port;
+
 	int baud = 9600;
 	int bits = 8;
 	int parity = 'n';
 	int flow = 'n';
 
-	if (co->index < 0 || co->index >= CDNS_UART_NR_PORTS)
-		return -EINVAL;
-
 	if (!port->membase) {
 		pr_debug("console on " CDNS_UART_TTY_NAME "%i not present\n",
 			 co->index);
@@ -1565,6 +1567,17 @@ static int cdns_uart_probe(struct platform_device *pdev)
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
 
+#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
+	/*
+	 * If console hasn't been found yet try to assign this port
+	 * because it is required to be assigned for console setup function.
+	 * If register_console() don't assign value, then console_port pointer
+	 * is cleanup.
+	 */
+	if (cdns_uart_uart_driver.cons->index == -1)
+		console_port = port;
+#endif
+
 	rc = uart_add_one_port(&cdns_uart_uart_driver, port);
 	if (rc) {
 		dev_err(&pdev->dev,
@@ -1572,6 +1585,12 @@ static int cdns_uart_probe(struct platform_device *pdev)
 		goto err_out_pm_disable;
 	}
 
+#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
+	/* This is not port which is used for console that's why clean it up */
+	if (cdns_uart_uart_driver.cons->index == -1)
+		console_port = NULL;
+#endif
+
 	return 0;
 
 err_out_pm_disable:
-- 
2.17.0