From c35aec61e5bb0faafb2847a0d750ebd7345a4b0f Mon Sep 17 00:00:00 2001 From: Yangbo Lu Date: Wed, 17 Jan 2018 15:40:24 +0800 Subject: [PATCH 28/30] tty: serial: support layerscape This is an integrated patch for layerscape uart support. Signed-off-by: Nikita Yushchenko Signed-off-by: Yuan Yao Signed-off-by: Stefan Agner Signed-off-by: Yangbo Lu --- 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; @@ -1351,6 +1353,18 @@ 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; @@ -1400,22 +1414,11 @@ 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); @@ -1645,6 +1648,13 @@ 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); @@ -1659,6 +1669,9 @@ 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 @@ -1666,6 +1679,13 @@ 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); @@ -1680,6 +1700,9 @@ lpuart32_console_write(struct console *c barrier(); lpuart32_write(old_cr, sport->port.membase + UARTCTRL); + + if (locked) + spin_unlock_irqrestore(&sport->port.lock, flags); } /* @@ -1904,13 +1927,13 @@ 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; - } - if (ret >= ARRAY_SIZE(lpuart_ports)) { - dev_err(&pdev->dev, "serial%d out of range\n", ret); - return -EINVAL; + 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"); @@ -1992,6 +2015,7 @@ 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); @@ -2076,12 +2100,10 @@ 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; - } } }