diff options
Diffstat (limited to 'drivers/tty/serial/sh-sci.c')
| -rw-r--r-- | drivers/tty/serial/sh-sci.c | 124 |
1 files changed, 104 insertions, 20 deletions
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index df523c744423..b1ea48f38248 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -157,6 +157,7 @@ struct sci_port { bool has_rtscts; bool autorts; + bool tx_occurred; }; #define SCI_NPORTS CONFIG_SERIAL_SH_SCI_NR_UARTS @@ -164,6 +165,8 @@ struct sci_port { static struct sci_port sci_ports[SCI_NPORTS]; static unsigned long sci_ports_in_use; static struct uart_driver sci_uart_driver; +static bool sci_uart_earlycon; +static bool sci_uart_earlycon_dev_probing; static inline struct sci_port * to_sci_port(struct uart_port *uart) @@ -850,6 +853,7 @@ static void sci_transmit_chars(struct uart_port *port) { struct tty_port *tport = &port->state->port; unsigned int stopped = uart_tx_stopped(port); + struct sci_port *s = to_sci_port(port); unsigned short status; unsigned short ctrl; int count; @@ -885,6 +889,7 @@ static void sci_transmit_chars(struct uart_port *port) } sci_serial_out(port, SCxTDR, c); + s->tx_occurred = true; port->icount.tx++; } while (--count > 0); @@ -1241,6 +1246,8 @@ static void sci_dma_tx_complete(void *arg) if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) uart_write_wakeup(port); + s->tx_occurred = true; + if (!kfifo_is_empty(&tport->xmit_fifo)) { s->cookie_tx = 0; schedule_work(&s->work_tx); @@ -1731,6 +1738,19 @@ static void sci_flush_buffer(struct uart_port *port) s->cookie_tx = -EINVAL; } } + +static void sci_dma_check_tx_occurred(struct sci_port *s) +{ + struct dma_tx_state state; + enum dma_status status; + + if (!s->chan_tx) + return; + + status = dmaengine_tx_status(s->chan_tx, s->cookie_tx, &state); + if (status == DMA_COMPLETE || status == DMA_IN_PROGRESS) + s->tx_occurred = true; +} #else /* !CONFIG_SERIAL_SH_SCI_DMA */ static inline void sci_request_dma(struct uart_port *port) { @@ -1740,6 +1760,10 @@ static inline void sci_free_dma(struct uart_port *port) { } +static void sci_dma_check_tx_occurred(struct sci_port *s) +{ +} + #define sci_flush_buffer NULL #endif /* !CONFIG_SERIAL_SH_SCI_DMA */ @@ -2076,6 +2100,12 @@ static unsigned int sci_tx_empty(struct uart_port *port) { unsigned short status = sci_serial_in(port, SCxSR); unsigned short in_tx_fifo = sci_txfill(port); + struct sci_port *s = to_sci_port(port); + + sci_dma_check_tx_occurred(s); + + if (!s->tx_occurred) + return TIOCSER_TEMT; return (status & SCxSR_TEND(port)) && !in_tx_fifo ? TIOCSER_TEMT : 0; } @@ -2247,6 +2277,7 @@ static int sci_startup(struct uart_port *port) dev_dbg(port->dev, "%s(%d)\n", __func__, port->line); + s->tx_occurred = false; sci_request_dma(port); ret = sci_request_irq(s); @@ -3027,10 +3058,6 @@ static int sci_init_single(struct platform_device *dev, ret = sci_init_clocks(sci_port, &dev->dev); if (ret < 0) return ret; - - port->dev = &dev->dev; - - pm_runtime_enable(&dev->dev); } port->type = p->type; @@ -3057,11 +3084,6 @@ static int sci_init_single(struct platform_device *dev, return 0; } -static void sci_cleanup_single(struct sci_port *port) -{ - pm_runtime_disable(port->port.dev); -} - #if defined(CONFIG_SERIAL_SH_SCI_CONSOLE) || \ defined(CONFIG_SERIAL_SH_SCI_EARLYCON) static void serial_console_putchar(struct uart_port *port, unsigned char ch) @@ -3231,8 +3253,6 @@ static void sci_remove(struct platform_device *dev) sci_ports_in_use &= ~BIT(port->port.line); uart_remove_one_port(&sci_uart_driver, &port->port); - sci_cleanup_single(port); - if (port->port.fifosize > 1) device_remove_file(&dev->dev, &dev_attr_rx_fifo_trigger); if (type == PORT_SCIFA || type == PORT_SCIFB || type == PORT_HSCIF) @@ -3367,7 +3387,8 @@ static struct plat_sci_port *sci_parse_dt(struct platform_device *pdev, static int sci_probe_single(struct platform_device *dev, unsigned int index, struct plat_sci_port *p, - struct sci_port *sciport) + struct sci_port *sciport, + struct resource *sci_res) { int ret; @@ -3396,6 +3417,11 @@ static int sci_probe_single(struct platform_device *dev, if (ret) return ret; + sciport->port.dev = &dev->dev; + ret = devm_pm_runtime_enable(&dev->dev); + if (ret) + return ret; + sciport->gpios = mctrl_gpio_init(&sciport->port, 0); if (IS_ERR(sciport->gpios)) return PTR_ERR(sciport->gpios); @@ -3409,18 +3435,37 @@ static int sci_probe_single(struct platform_device *dev, sciport->port.flags |= UPF_HARD_FLOW; } - ret = uart_add_one_port(&sci_uart_driver, &sciport->port); - if (ret) { - sci_cleanup_single(sciport); - return ret; + if (sci_uart_earlycon && sci_ports[0].port.mapbase == sci_res->start) { + /* + * In case: + * - this is the earlycon port (mapped on index 0 in sci_ports[]) and + * - it now maps to an alias other than zero and + * - the earlycon is still alive (e.g., "earlycon keep_bootcon" is + * available in bootargs) + * + * we need to avoid disabling clocks and PM domains through the runtime + * PM APIs called in __device_attach(). For this, increment the runtime + * PM reference counter (the clocks and PM domains were already enabled + * by the bootloader). Otherwise the earlycon may access the HW when it + * has no clocks enabled leading to failures (infinite loop in + * sci_poll_put_char()). + */ + pm_runtime_get_noresume(&dev->dev); + + /* + * Skip cleanup the sci_port[0] in early_console_exit(), this + * port is the same as the earlycon one. + */ + sci_uart_earlycon_dev_probing = true; } - return 0; + return uart_add_one_port(&sci_uart_driver, &sciport->port); } static int sci_probe(struct platform_device *dev) { struct plat_sci_port *p; + struct resource *res; struct sci_port *sp; unsigned int dev_id; int ret; @@ -3450,9 +3495,29 @@ static int sci_probe(struct platform_device *dev) } sp = &sci_ports[dev_id]; + + /* + * In case: + * - the probed port alias is zero (as the one used by earlycon), and + * - the earlycon is still active (e.g., "earlycon keep_bootcon" in + * bootargs) + * + * defer the probe of this serial. This is a debug scenario and the user + * must be aware of it. + * + * Except when the probed port is the same as the earlycon port. + */ + + res = platform_get_resource(dev, IORESOURCE_MEM, 0); + if (!res) + return -ENODEV; + + if (sci_uart_earlycon && sp == &sci_ports[0] && sp->port.mapbase != res->start) + return dev_err_probe(&dev->dev, -EBUSY, "sci_port[0] is used by earlycon!\n"); + platform_set_drvdata(dev, sp); - ret = sci_probe_single(dev, dev_id, p, sp); + ret = sci_probe_single(dev, dev_id, p, sp, res); if (ret) return ret; @@ -3533,7 +3598,23 @@ sh_early_platform_init_buffer("earlyprintk", &sci_driver, early_serial_buf, ARRAY_SIZE(early_serial_buf)); #endif #ifdef CONFIG_SERIAL_SH_SCI_EARLYCON -static struct plat_sci_port port_cfg __initdata; +static struct plat_sci_port port_cfg; + +static int early_console_exit(struct console *co) +{ + struct sci_port *sci_port = &sci_ports[0]; + + /* + * Clean the slot used by earlycon. A new SCI device might + * map to this slot. + */ + if (!sci_uart_earlycon_dev_probing) { + memset(sci_port, 0, sizeof(*sci_port)); + sci_uart_earlycon = false; + } + + return 0; +} static int __init early_console_setup(struct earlycon_device *device, int type) @@ -3542,15 +3623,18 @@ static int __init early_console_setup(struct earlycon_device *device, return -ENODEV; device->port.type = type; - memcpy(&sci_ports[0].port, &device->port, sizeof(struct uart_port)); + sci_ports[0].port = device->port; port_cfg.type = type; sci_ports[0].cfg = &port_cfg; sci_ports[0].params = sci_probe_regmap(&port_cfg); + sci_uart_earlycon = true; port_cfg.scscr = sci_serial_in(&sci_ports[0].port, SCSCR); sci_serial_out(&sci_ports[0].port, SCSCR, SCSCR_RE | SCSCR_TE | port_cfg.scscr); device->con->write = serial_console_write; + device->con->exit = early_console_exit; + return 0; } static int __init sci_early_console_setup(struct earlycon_device *device, |