From 469daac0faff06209bc1d1390571b860d153a82b Mon Sep 17 00:00:00 2001
From: Yangbo Lu <yangbo.lu@nxp.com>
Date: Wed, 27 Sep 2017 10:33:47 +0800
Subject: [PATCH] tty: serial: support layerscape
This is a integrated patch for layerscape uart support.
Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Signed-off-by: Yuan Yao <yao.yuan@nxp.com>
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
---
drivers/tty/serial/fsl_lpuart.c | 66 ++++++++++++++++++++++++++++-------------
1 file changed, 46 insertions(+), 20 deletions(-)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -231,6 +231,8 @@
#define DEV_NAME "ttyLP"
#define UART_NR 6
+static DECLARE_BITMAP(linemap, UART_NR);
+
struct lpuart_port {
struct uart_port port;
struct clk *clk;
@@ -1348,6 +1350,18 @@ lpuart_set_termios(struct uart_port *por
/* ask the core to calculate the divisor */
baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 16);
+ /*
+ * Need to update the Ring buffer length according to the selected
+ * baud rate and restart Rx DMA path.
+ *
+ * Since timer function acqures sport->port.lock, need to stop before
+ * acquring same lock because otherwise del_timer_sync() can deadlock.
+ */
+ if (old && sport->lpuart_dma_rx_use) {
+ del_timer_sync(&sport->lpuart_timer);
+ lpuart_dma_rx_free(&sport->port);
+ }
+
spin_lock_irqsave(&sport->port.lock, flags);
sport->port.read_status_mask = 0;
@@ -1397,22 +1411,11 @@ lpuart_set_termios(struct uart_port *por
/* restore control register */
writeb(old_cr2, sport->port.membase + UARTCR2);
- /*
- * If new baud rate is set, we will also need to update the Ring buffer
- * length according to the selected baud rate and restart Rx DMA path.
- */
- if (old) {
- if (sport->lpuart_dma_rx_use) {
- del_timer_sync(&sport->lpuart_timer);
- lpuart_dma_rx_free(&sport->port);
- }
-
- if (sport->dma_rx_chan && !lpuart_start_rx_dma(sport)) {
- sport->lpuart_dma_rx_use = true;
+ if (old && sport->lpuart_dma_rx_use) {
+ if (!lpuart_start_rx_dma(sport))
rx_dma_timer_init(sport);
- } else {
+ else
sport->lpuart_dma_rx_use = false;
- }
}
spin_unlock_irqrestore(&sport->port.lock, flags);
@@ -1640,6 +1643,13 @@ lpuart_console_write(struct console *co,
{
struct lpuart_port *sport = lpuart_ports[co->index];
unsigned char old_cr2, cr2;
+ unsigned long flags;
+ int locked = 1;
+
+ if (sport->port.sysrq || oops_in_progress)
+ locked = spin_trylock_irqsave(&sport->port.lock, flags);
+ else
+ spin_lock_irqsave(&sport->port.lock, flags);
/* first save CR2 and then disable interrupts */
cr2 = old_cr2 = readb(sport->port.membase + UARTCR2);
@@ -1654,6 +1664,9 @@ lpuart_console_write(struct console *co,
barrier();
writeb(old_cr2, sport->port.membase + UARTCR2);
+
+ if (locked)
+ spin_unlock_irqrestore(&sport->port.lock, flags);
}
static void
@@ -1661,6 +1674,13 @@ lpuart32_console_write(struct console *c
{
struct lpuart_port *sport = lpuart_ports[co->index];
unsigned long old_cr, cr;
+ unsigned long flags;
+ int locked = 1;
+
+ if (sport->port.sysrq || oops_in_progress)
+ locked = spin_trylock_irqsave(&sport->port.lock, flags);
+ else
+ spin_lock_irqsave(&sport->port.lock, flags);
/* first save CR2 and then disable interrupts */
cr = old_cr = lpuart32_read(sport->port.membase + UARTCTRL);
@@ -1675,6 +1695,9 @@ lpuart32_console_write(struct console *c
barrier();
lpuart32_write(old_cr, sport->port.membase + UARTCTRL);
+
+ if (locked)
+ spin_unlock_irqrestore(&sport->port.lock, flags);
}
/*
@@ -1899,9 +1922,13 @@ static int lpuart_probe(struct platform_
ret = of_alias_get_id(np, "serial");
if (ret < 0) {
- dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
- return ret;
+ ret = find_first_zero_bit(linemap, UART_NR);
+ if (ret >= UART_NR) {
+ dev_err(&pdev->dev, "port line is full, add device failed\n");
+ return ret;
+ }
}
+ set_bit(ret, linemap);
sport->port.line = ret;
sport->lpuart32 = of_device_is_compatible(np, "fsl,ls1021a-lpuart");
@@ -1983,6 +2010,7 @@ static int lpuart_remove(struct platform
struct lpuart_port *sport = platform_get_drvdata(pdev);
uart_remove_one_port(&lpuart_reg, &sport->port);
+ clear_bit(sport->port.line, linemap);
clk_disable_unprepare(sport->clk);
@@ -2067,12 +2095,10 @@ static int lpuart_resume(struct device *
if (sport->lpuart_dma_rx_use) {
if (sport->port.irq_wake) {
- if (!lpuart_start_rx_dma(sport)) {
- sport->lpuart_dma_rx_use = true;
+ if (!lpuart_start_rx_dma(sport))
rx_dma_timer_init(sport);
- } else {
+ else
sport->lpuart_dma_rx_use = false;
- }
}
}