diff options
Diffstat (limited to 'drivers/tty/serial/imx.c')
| -rw-r--r-- | drivers/tty/serial/imx.c | 100 |
1 files changed, 80 insertions, 20 deletions
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index f4f40c9373c2..67d4a72eda77 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -120,6 +120,7 @@ #define UCR4_OREN (1<<1) /* Receiver overrun interrupt enable */ #define UCR4_DREN (1<<0) /* Recv data ready interrupt enable */ #define UFCR_RXTL_SHF 0 /* Receiver trigger level shift */ +#define UFCR_RXTL_MASK 0x3F /* Receiver trigger 6 bits wide */ #define UFCR_DCEDTE (1<<6) /* DCE/DTE mode select */ #define UFCR_RFDIV (7<<7) /* Reference freq divider mask */ #define UFCR_RFDIV_REG(x) (((x) < 7 ? 6 - (x) : 6) << 7) @@ -264,6 +265,11 @@ static const struct of_device_id imx_uart_dt_ids[] = { }; MODULE_DEVICE_TABLE(of, imx_uart_dt_ids); +static inline struct imx_port *to_imx_port(struct uart_port *port) +{ + return container_of(port, struct imx_port, port); +} + static inline void imx_uart_writel(struct imx_port *sport, u32 val, u32 offset) { writel(val, sport->port.membase + offset); @@ -377,7 +383,7 @@ static void imx_uart_disable_loopback_rs485(struct imx_port *sport) /* called with port.lock taken and irqs off */ static void imx_uart_start_rx(struct uart_port *port) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); unsigned int ucr1, ucr2; ucr1 = imx_uart_readl(sport, UCR1); @@ -401,7 +407,7 @@ static void imx_uart_start_rx(struct uart_port *port) /* called with port.lock taken and irqs off */ static void imx_uart_stop_tx(struct uart_port *port) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); u32 ucr1, ucr4, usr2; if (sport->tx_state == OFF) @@ -466,7 +472,7 @@ static void imx_uart_stop_tx(struct uart_port *port) static void imx_uart_stop_rx_with_loopback_ctrl(struct uart_port *port, bool loopback) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); u32 ucr1, ucr2, ucr4, uts; ucr1 = imx_uart_readl(sport, UCR1); @@ -511,7 +517,7 @@ static void imx_uart_stop_rx(struct uart_port *port) /* called with port.lock taken and irqs off */ static void imx_uart_enable_ms(struct uart_port *port) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); mod_timer(&sport->timer, jiffies); @@ -662,7 +668,7 @@ static void imx_uart_dma_tx(struct imx_port *sport) /* called with port.lock taken and irqs off */ static void imx_uart_start_tx(struct uart_port *port) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); struct tty_port *tport = &sport->port.state->port; u32 ucr1; @@ -1043,7 +1049,7 @@ static irqreturn_t imx_uart_int(int irq, void *dev_id) */ static unsigned int imx_uart_tx_empty(struct uart_port *port) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); unsigned int ret; ret = (imx_uart_readl(sport, USR2) & USR2_TXDC) ? TIOCSER_TEMT : 0; @@ -1058,7 +1064,7 @@ static unsigned int imx_uart_tx_empty(struct uart_port *port) /* called with port.lock taken and irqs off */ static unsigned int imx_uart_get_mctrl(struct uart_port *port) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); unsigned int ret = imx_uart_get_hwmctrl(sport); mctrl_gpio_get(sport->gpios, &ret); @@ -1069,7 +1075,7 @@ static unsigned int imx_uart_get_mctrl(struct uart_port *port) /* called with port.lock taken and irqs off */ static void imx_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); u32 ucr3, uts; if (!(port->rs485.flags & SER_RS485_ENABLED)) { @@ -1112,7 +1118,7 @@ static void imx_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) */ static void imx_uart_break_ctl(struct uart_port *port, int break_state) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); unsigned long flags; u32 ucr1; @@ -1434,7 +1440,7 @@ static void imx_uart_disable_dma(struct imx_port *sport) static int imx_uart_startup(struct uart_port *port) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); int retval; unsigned long flags; int dma_is_inited = 0; @@ -1548,9 +1554,10 @@ static int imx_uart_startup(struct uart_port *port) static void imx_uart_shutdown(struct uart_port *port) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); unsigned long flags; u32 ucr1, ucr2, ucr4, uts; + int loops; if (sport->dma_is_enabled) { dmaengine_terminate_sync(sport->dma_chan_tx); @@ -1613,6 +1620,56 @@ static void imx_uart_shutdown(struct uart_port *port) ucr4 &= ~UCR4_TCEN; imx_uart_writel(sport, ucr4, UCR4); + /* + * We have to ensure the tx state machine ends up in OFF. This + * is especially important for rs485 where we must not leave + * the RTS signal high, blocking the bus indefinitely. + * + * All interrupts are now disabled, so imx_uart_stop_tx() will + * no longer be called from imx_uart_transmit_buffer(). It may + * still be called via the hrtimers, and if those are in play, + * we have to honour the delays. + */ + if (sport->tx_state == WAIT_AFTER_RTS || sport->tx_state == SEND) + imx_uart_stop_tx(port); + + /* + * In many cases (rs232 mode, or if tx_state was + * WAIT_AFTER_RTS, or if tx_state was SEND and there is no + * delay_rts_after_send), this will have moved directly to + * OFF. In rs485 mode, tx_state might already have been + * WAIT_AFTER_SEND and the hrtimer thus already started, or + * the above imx_uart_stop_tx() call could have started it. In + * those cases, we have to wait for the hrtimer to fire and + * complete the transition to OFF. + */ + loops = port->rs485.flags & SER_RS485_ENABLED ? + port->rs485.delay_rts_after_send : 0; + while (sport->tx_state != OFF && loops--) { + uart_port_unlock_irqrestore(&sport->port, flags); + msleep(1); + uart_port_lock_irqsave(&sport->port, &flags); + } + + if (sport->tx_state != OFF) { + dev_warn(sport->port.dev, "unexpected tx_state %d\n", + sport->tx_state); + /* + * This machine may be busted, but ensure the RTS + * signal is inactive in order not to block other + * devices. + */ + if (port->rs485.flags & SER_RS485_ENABLED) { + ucr2 = imx_uart_readl(sport, UCR2); + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) + imx_uart_rts_active(sport, &ucr2); + else + imx_uart_rts_inactive(sport, &ucr2); + imx_uart_writel(sport, ucr2, UCR2); + } + sport->tx_state = OFF; + } + uart_port_unlock_irqrestore(&sport->port, flags); clk_disable_unprepare(sport->clk_per); @@ -1622,7 +1679,7 @@ static void imx_uart_shutdown(struct uart_port *port) /* called with port.lock taken and irqs off */ static void imx_uart_flush_buffer(struct uart_port *port) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); struct scatterlist *sgl = &sport->tx_sgl[0]; if (!sport->dma_chan_tx) @@ -1649,7 +1706,7 @@ static void imx_uart_set_termios(struct uart_port *port, struct ktermios *termios, const struct ktermios *old) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); unsigned long flags; u32 ucr2, old_ucr2, ufcr; unsigned int baud, quot; @@ -1852,7 +1909,7 @@ imx_uart_verify_port(struct uart_port *port, struct serial_struct *ser) static int imx_uart_poll_init(struct uart_port *port) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); unsigned long flags; u32 ucr1, ucr2; int retval; @@ -1901,7 +1958,7 @@ static int imx_uart_poll_init(struct uart_port *port) static int imx_uart_poll_get_char(struct uart_port *port) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); if (!(imx_uart_readl(sport, USR2) & USR2_RDR)) return NO_POLL_CHAR; @@ -1910,7 +1967,7 @@ static int imx_uart_poll_get_char(struct uart_port *port) static void imx_uart_poll_put_char(struct uart_port *port, unsigned char c) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); unsigned int status; /* drain */ @@ -1932,8 +1989,8 @@ static void imx_uart_poll_put_char(struct uart_port *port, unsigned char c) static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termios, struct serial_rs485 *rs485conf) { - struct imx_port *sport = (struct imx_port *)port; - u32 ucr2; + struct imx_port *sport = to_imx_port(port); + u32 ucr2, ufcr; if (rs485conf->flags & SER_RS485_ENABLED) { /* Enable receiver if low-active RTS signal is requested */ @@ -1953,7 +2010,10 @@ static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termio /* Make sure Rx is enabled in case Tx is active with Rx disabled */ if (!(rs485conf->flags & SER_RS485_ENABLED) || rs485conf->flags & SER_RS485_RX_DURING_TX) { - imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); + /* If the receiver trigger is 0, set it to a default value */ + ufcr = imx_uart_readl(sport, UFCR); + if ((ufcr & UFCR_RXTL_MASK) == 0) + imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); imx_uart_start_rx(port); } @@ -1988,7 +2048,7 @@ static struct imx_port *imx_uart_ports[UART_NR]; #if IS_ENABLED(CONFIG_SERIAL_IMX_CONSOLE) static void imx_uart_console_putchar(struct uart_port *port, unsigned char ch) { - struct imx_port *sport = (struct imx_port *)port; + struct imx_port *sport = to_imx_port(port); while (imx_uart_readl(sport, imx_uart_uts_reg(sport)) & UTS_TXFULL) barrier(); |