From ec063899b7b308019afa9f5eb32f0a58a6c6ee53 Mon Sep 17 00:00:00 2001 From: Alexander Shiyan Date: Mon, 3 Dec 2012 22:23:31 +0400 Subject: [PATCH] serial: sccnxp: Implement polling mode This patch adds support for polling work mode, i.e. system is perform periodical check chip status when IRQ-line is not connected to CPU. Signed-off-by: Alexander Shiyan Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sccnxp.c | 148 +++++++++++++++++++-------- include/linux/platform_data/sccnxp.h | 2 + 2 files changed, 105 insertions(+), 45 deletions(-) diff --git a/drivers/tty/serial/sccnxp.c b/drivers/tty/serial/sccnxp.c index 2ced871becff..3a4c57e6ea1e 100644 --- a/drivers/tty/serial/sccnxp.c +++ b/drivers/tty/serial/sccnxp.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include @@ -106,6 +107,7 @@ enum { struct sccnxp_port { struct uart_driver uart; struct uart_port port[SCCNXP_MAX_UARTS]; + bool opened[SCCNXP_MAX_UARTS]; const char *name; int irq; @@ -122,7 +124,10 @@ struct sccnxp_port { struct console console; #endif - struct mutex sccnxp_mutex; + spinlock_t lock; + + bool poll; + struct timer_list timer; struct sccnxp_pdata pdata; }; @@ -371,31 +376,48 @@ static void sccnxp_handle_tx(struct uart_port *port) uart_write_wakeup(port); } -static irqreturn_t sccnxp_ist(int irq, void *dev_id) +static void sccnxp_handle_events(struct sccnxp_port *s) { int i; u8 isr; - struct sccnxp_port *s = (struct sccnxp_port *)dev_id; - - mutex_lock(&s->sccnxp_mutex); - for (;;) { + do { isr = sccnxp_read(&s->port[0], SCCNXP_ISR_REG); isr &= s->imr; if (!isr) break; - dev_dbg(s->port[0].dev, "IRQ status: 0x%02x\n", isr); - for (i = 0; i < s->uart.nr; i++) { - if (isr & ISR_RXRDY(i)) + if (s->opened[i] && (isr & ISR_RXRDY(i))) sccnxp_handle_rx(&s->port[i]); - if (isr & ISR_TXRDY(i)) + if (s->opened[i] && (isr & ISR_TXRDY(i))) sccnxp_handle_tx(&s->port[i]); } - } + } while (1); +} + +static void sccnxp_timer(unsigned long data) +{ + struct sccnxp_port *s = (struct sccnxp_port *)data; + unsigned long flags; - mutex_unlock(&s->sccnxp_mutex); + spin_lock_irqsave(&s->lock, flags); + sccnxp_handle_events(s); + spin_unlock_irqrestore(&s->lock, flags); + + if (!timer_pending(&s->timer)) + mod_timer(&s->timer, jiffies + + usecs_to_jiffies(s->pdata.poll_time_us)); +} + +static irqreturn_t sccnxp_ist(int irq, void *dev_id) +{ + struct sccnxp_port *s = (struct sccnxp_port *)dev_id; + unsigned long flags; + + spin_lock_irqsave(&s->lock, flags); + sccnxp_handle_events(s); + spin_unlock_irqrestore(&s->lock, flags); return IRQ_HANDLED; } @@ -403,8 +425,9 @@ static irqreturn_t sccnxp_ist(int irq, void *dev_id) static void sccnxp_start_tx(struct uart_port *port) { struct sccnxp_port *s = dev_get_drvdata(port->dev); + unsigned long flags; - mutex_lock(&s->sccnxp_mutex); + spin_lock_irqsave(&s->lock, flags); /* Set direction to output */ if (s->flags & SCCNXP_HAVE_IO) @@ -412,7 +435,7 @@ static void sccnxp_start_tx(struct uart_port *port) sccnxp_enable_irq(port, IMR_TXRDY); - mutex_unlock(&s->sccnxp_mutex); + spin_unlock_irqrestore(&s->lock, flags); } static void sccnxp_stop_tx(struct uart_port *port) @@ -423,20 +446,22 @@ static void sccnxp_stop_tx(struct uart_port *port) static void sccnxp_stop_rx(struct uart_port *port) { struct sccnxp_port *s = dev_get_drvdata(port->dev); + unsigned long flags; - mutex_lock(&s->sccnxp_mutex); + spin_lock_irqsave(&s->lock, flags); sccnxp_port_write(port, SCCNXP_CR_REG, CR_RX_DISABLE); - mutex_unlock(&s->sccnxp_mutex); + spin_unlock_irqrestore(&s->lock, flags); } static unsigned int sccnxp_tx_empty(struct uart_port *port) { u8 val; + unsigned long flags; struct sccnxp_port *s = dev_get_drvdata(port->dev); - mutex_lock(&s->sccnxp_mutex); + spin_lock_irqsave(&s->lock, flags); val = sccnxp_port_read(port, SCCNXP_SR_REG); - mutex_unlock(&s->sccnxp_mutex); + spin_unlock_irqrestore(&s->lock, flags); return (val & SR_TXEMT) ? TIOCSER_TEMT : 0; } @@ -449,28 +474,30 @@ static void sccnxp_enable_ms(struct uart_port *port) static void sccnxp_set_mctrl(struct uart_port *port, unsigned int mctrl) { struct sccnxp_port *s = dev_get_drvdata(port->dev); + unsigned long flags; if (!(s->flags & SCCNXP_HAVE_IO)) return; - mutex_lock(&s->sccnxp_mutex); + spin_lock_irqsave(&s->lock, flags); sccnxp_set_bit(port, DTR_OP, mctrl & TIOCM_DTR); sccnxp_set_bit(port, RTS_OP, mctrl & TIOCM_RTS); - mutex_unlock(&s->sccnxp_mutex); + spin_unlock_irqrestore(&s->lock, flags); } static unsigned int sccnxp_get_mctrl(struct uart_port *port) { u8 bitmask, ipr; + unsigned long flags; struct sccnxp_port *s = dev_get_drvdata(port->dev); unsigned int mctrl = TIOCM_DSR | TIOCM_CTS | TIOCM_CAR; if (!(s->flags & SCCNXP_HAVE_IO)) return mctrl; - mutex_lock(&s->sccnxp_mutex); + spin_lock_irqsave(&s->lock, flags); ipr = ~sccnxp_read(port, SCCNXP_IPCR_REG); @@ -499,7 +526,7 @@ static unsigned int sccnxp_get_mctrl(struct uart_port *port) mctrl |= (ipr & bitmask) ? TIOCM_RNG : 0; } - mutex_unlock(&s->sccnxp_mutex); + spin_unlock_irqrestore(&s->lock, flags); return mctrl; } @@ -507,21 +534,23 @@ static unsigned int sccnxp_get_mctrl(struct uart_port *port) static void sccnxp_break_ctl(struct uart_port *port, int break_state) { struct sccnxp_port *s = dev_get_drvdata(port->dev); + unsigned long flags; - mutex_lock(&s->sccnxp_mutex); + spin_lock_irqsave(&s->lock, flags); sccnxp_port_write(port, SCCNXP_CR_REG, break_state ? CR_CMD_START_BREAK : CR_CMD_STOP_BREAK); - mutex_unlock(&s->sccnxp_mutex); + spin_unlock_irqrestore(&s->lock, flags); } static void sccnxp_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { struct sccnxp_port *s = dev_get_drvdata(port->dev); + unsigned long flags; u8 mr1, mr2; int baud; - mutex_lock(&s->sccnxp_mutex); + spin_lock_irqsave(&s->lock, flags); /* Mask termios capabilities we don't support */ termios->c_cflag &= ~CMSPAR; @@ -588,20 +617,22 @@ static void sccnxp_set_termios(struct uart_port *port, /* Update timeout according to new baud rate */ uart_update_timeout(port, termios->c_cflag, baud); + /* Report actual baudrate back to core */ if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); /* Enable RX & TX */ sccnxp_port_write(port, SCCNXP_CR_REG, CR_RX_ENABLE | CR_TX_ENABLE); - mutex_unlock(&s->sccnxp_mutex); + spin_unlock_irqrestore(&s->lock, flags); } static int sccnxp_startup(struct uart_port *port) { struct sccnxp_port *s = dev_get_drvdata(port->dev); + unsigned long flags; - mutex_lock(&s->sccnxp_mutex); + spin_lock_irqsave(&s->lock, flags); if (s->flags & SCCNXP_HAVE_IO) { /* Outputs are controlled manually */ @@ -620,7 +651,9 @@ static int sccnxp_startup(struct uart_port *port) /* Enable RX interrupt */ sccnxp_enable_irq(port, IMR_RXRDY); - mutex_unlock(&s->sccnxp_mutex); + s->opened[port->line] = 1; + + spin_unlock_irqrestore(&s->lock, flags); return 0; } @@ -628,8 +661,11 @@ static int sccnxp_startup(struct uart_port *port) static void sccnxp_shutdown(struct uart_port *port) { struct sccnxp_port *s = dev_get_drvdata(port->dev); + unsigned long flags; + + spin_lock_irqsave(&s->lock, flags); - mutex_lock(&s->sccnxp_mutex); + s->opened[port->line] = 0; /* Disable interrupts */ sccnxp_disable_irq(port, IMR_TXRDY | IMR_RXRDY); @@ -641,7 +677,7 @@ static void sccnxp_shutdown(struct uart_port *port) if (s->flags & SCCNXP_HAVE_IO) sccnxp_set_bit(port, DIR_OP, 0); - mutex_unlock(&s->sccnxp_mutex); + spin_unlock_irqrestore(&s->lock, flags); } static const char *sccnxp_type(struct uart_port *port) @@ -715,10 +751,11 @@ static void sccnxp_console_write(struct console *co, const char *c, unsigned n) { struct sccnxp_port *s = (struct sccnxp_port *)co->data; struct uart_port *port = &s->port[co->index]; + unsigned long flags; - mutex_lock(&s->sccnxp_mutex); + spin_lock_irqsave(&s->lock, flags); uart_console_write(port, c, n, sccnxp_console_putchar); - mutex_unlock(&s->sccnxp_mutex); + spin_unlock_irqrestore(&s->lock, flags); } static int sccnxp_console_setup(struct console *co, char *options) @@ -757,7 +794,7 @@ static int sccnxp_probe(struct platform_device *pdev) } platform_set_drvdata(pdev, s); - mutex_init(&s->sccnxp_mutex); + spin_lock_init(&s->lock); /* Individual chip settings */ switch (chiptype) { @@ -854,11 +891,19 @@ static int sccnxp_probe(struct platform_device *pdev) } else memcpy(&s->pdata, pdata, sizeof(struct sccnxp_pdata)); - s->irq = platform_get_irq(pdev, 0); - if (s->irq <= 0) { - dev_err(&pdev->dev, "Missing irq resource data\n"); - ret = -ENXIO; - goto err_out; + if (pdata->poll_time_us) { + dev_info(&pdev->dev, "Using poll mode, resolution %u usecs\n", + pdata->poll_time_us); + s->poll = 1; + } + + if (!s->poll) { + s->irq = platform_get_irq(pdev, 0); + if (s->irq < 0) { + dev_err(&pdev->dev, "Missing irq resource data\n"); + ret = -ENXIO; + goto err_out; + } } /* Check input frequency */ @@ -923,13 +968,23 @@ static int sccnxp_probe(struct platform_device *pdev) if (s->pdata.init) s->pdata.init(); - ret = devm_request_threaded_irq(&pdev->dev, s->irq, NULL, sccnxp_ist, - IRQF_TRIGGER_FALLING | IRQF_ONESHOT, - dev_name(&pdev->dev), s); - if (!ret) + if (!s->poll) { + ret = devm_request_threaded_irq(&pdev->dev, s->irq, NULL, + sccnxp_ist, + IRQF_TRIGGER_FALLING | + IRQF_ONESHOT, + dev_name(&pdev->dev), s); + if (!ret) + return 0; + + dev_err(&pdev->dev, "Unable to reguest IRQ %i\n", s->irq); + } else { + init_timer(&s->timer); + setup_timer(&s->timer, sccnxp_timer, (unsigned long)s); + mod_timer(&s->timer, jiffies + + usecs_to_jiffies(s->pdata.poll_time_us)); return 0; - - dev_err(&pdev->dev, "Unable to reguest IRQ %i\n", s->irq); + } err_out: platform_set_drvdata(pdev, NULL); @@ -942,7 +997,10 @@ static int sccnxp_remove(struct platform_device *pdev) int i; struct sccnxp_port *s = platform_get_drvdata(pdev); - devm_free_irq(&pdev->dev, s->irq, s); + if (!s->poll) + devm_free_irq(&pdev->dev, s->irq, s); + else + del_timer_sync(&s->timer); for (i = 0; i < s->uart.nr; i++) uart_remove_one_port(&s->uart, &s->port[i]); diff --git a/include/linux/platform_data/sccnxp.h b/include/linux/platform_data/sccnxp.h index 7311ccd3217f..096de90cf848 100644 --- a/include/linux/platform_data/sccnxp.h +++ b/include/linux/platform_data/sccnxp.h @@ -84,6 +84,8 @@ struct sccnxp_pdata { const u8 reg_shift; /* Modem control lines configuration */ const u32 mctrl_cfg[SCCNXP_MAX_UARTS]; + /* Timer value for polling mode (usecs) */ + const unsigned int poll_time_us; /* Called during startup */ void (*init)(void); /* Called before finish */ -- 2.20.1