/**************************************************************************** * arch/arm/src/lpc31xx/lpc31_serial.c * * Copyright (C) 2009, 2012 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include "up_arch.h" #include "os_internal.h" #include "up_internal.h" #include "lpc31_cgudrvr.h" #include "lpc31_uart.h" #ifdef USE_SERIALDRIVER /**************************************************************************** * Definitions ****************************************************************************/ /**************************************************************************** * Private Types ****************************************************************************/ struct up_dev_s { uint8_t ier; /* Saved IER value */ }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static inline void up_disableuartint(struct up_dev_s *priv, uint8_t *ier); static inline void up_restoreuartint(struct up_dev_s *priv, uint8_t ier); static inline void up_enablebreaks(void); static inline void up_disablebreaks(void); static inline void up_configbaud(void); static int up_setup(struct uart_dev_s *dev); static void up_shutdown(struct uart_dev_s *dev); static int up_attach(struct uart_dev_s *dev); static void up_detach(struct uart_dev_s *dev); static int up_interrupt(int irq, void *context); static int up_ioctl(struct file *filep, int cmd, unsigned long arg); static int up_receive(struct uart_dev_s *dev, uint32_t *status); static void up_rxint(struct uart_dev_s *dev, bool enable); static bool up_rxavailable(struct uart_dev_s *dev); static void up_send(struct uart_dev_s *dev, int ch); static void up_txint(struct uart_dev_s *dev, bool enable); static bool up_txready(struct uart_dev_s *dev); static bool up_txempty(struct uart_dev_s *dev); /**************************************************************************** * Private Variables ****************************************************************************/ struct uart_ops_s g_uart_ops = { .setup = up_setup, .shutdown = up_shutdown, .attach = up_attach, .detach = up_detach, .ioctl = up_ioctl, .receive = up_receive, .rxint = up_rxint, .rxavailable = up_rxavailable, .send = up_send, .txint = up_txint, .txready = up_txready, .txempty = up_txempty, }; /* I/O buffers */ static char g_rxbuffer[CONFIG_UART_RXBUFSIZE]; static char g_txbuffer[CONFIG_UART_TXBUFSIZE]; /* This describes the state of the single LPC313XX uart port. */ static struct up_dev_s g_uartpriv; static uart_dev_t g_uartport = { .recv = { .size = CONFIG_UART_RXBUFSIZE, .buffer = g_rxbuffer, }, .xmit = { .size = CONFIG_UART_TXBUFSIZE, .buffer = g_txbuffer, }, .ops = &g_uart_ops, .priv = &g_uartpriv, }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: up_disableuartint ****************************************************************************/ static inline void up_disableuartint(struct up_dev_s *priv, uint8_t *ier) { if (ier) { *ier = priv->ier & UART_IER_ALLINTS; } priv->ier &= ~UART_IER_ALLINTS; putreg32((uint32_t)priv->ier, LPC31_UART_IER); } /**************************************************************************** * Name: up_restoreuartint ****************************************************************************/ static inline void up_restoreuartint(struct up_dev_s *priv, uint8_t ier) { priv->ier |= ier & UART_IER_ALLINTS; putreg32((uint32_t)priv->ier, LPC31_UART_IER); } /**************************************************************************** * Name: up_enablebreaks ****************************************************************************/ static inline void up_enablebreaks(void) { uint32_t lcr = getreg32(LPC31_UART_LCR); lcr |= UART_LCR_BRKCTRL; putreg32(lcr, LPC31_UART_LCR); } /**************************************************************************** * Name: up_disablebreaks ****************************************************************************/ static inline void up_disablebreaks(void) { uint32_t lcr = getreg32(LPC31_UART_LCR); lcr &= ~UART_LCR_BRKCTRL; putreg32(lcr, LPC31_UART_LCR); } /**************************************************************************** * Name: up_configbaud ****************************************************************************/ static inline void up_configbaud(void) { /* In a buckled-up, embedded system, there is no reason to constantly * calculate the following. The calculation can be skipped if the * MULVAL, DIVADDVAL, and DIVISOR values are provided in the configuration * file. */ #ifndef CONFIG_LPC31_UART_MULVAL uint32_t qtrclk; uint32_t regval; /* Test values calculated for every multiplier/divisor combination */ uint32_t tdiv; uint32_t terr; int tmulval; int tdivaddval; /* Optimal multiplier/divider values */ uint32_t div = 0; uint32_t err = 100000; int mulval = 1; int divaddval = 0; /* Baud is generated using FDR and DLL-DLM registers * * baud = clock * (mulval/(mulval+divaddval) / (16 * div) * * Or * * div = (clock/16) * (mulval/(mulval+divaddval) / baud * * Where mulval = Fractional divider multiplier * divaddval = Fractional divider pre-scale div * div = DLL-DLM divisor */ /* Get UART block clock divided by 16 */ qtrclk = lpc31_clkfreq(CLKID_UARTUCLK, DOMAINID_UART) >> 4; /* Try every valid multiplier, tmulval (or until a perfect * match is found). */ for (tmulval = 1 ; tmulval <= 15 && err > 0; tmulval++) { /* Try every valid pre-scale div, tdivaddval (or until a perfect * match is found). */ for (tdivaddval = 0 ; tdivaddval <= 15 && err > 0; tdivaddval++) { /* Calculate the divisor with these fractional divider settings */ uint32_t tmp = (tmulval * qtrclk) / ((tmulval + tdivaddval)); tdiv = (tmp + (CONFIG_UART_BAUD>>1)) / CONFIG_UART_BAUD; /* Check if this candidate divisor is within a valid range */ if (tdiv > 2 && tdiv < 0x10000) { /* Calculate the actual baud and the error */ uint32_t actualbaud = tmp / tdiv; if (actualbaud <= CONFIG_UART_BAUD) { terr = CONFIG_UART_BAUD - actualbaud; } else { terr = actualbaud - CONFIG_UART_BAUD; } /* Is this the smallest error we have encountered? */ if (terr < err) { /* Yes, save these settings as the new, candidate optimal settings */ mulval = tmulval ; divaddval = tdivaddval; div = tdiv; err = terr; } } } } /* Set the Divisor Latch Access Bit (DLAB) to enable DLL/DLM access */ regval = getreg32(LPC31_UART_LCR); regval |= UART_LCR_DLAB; putreg32(regval, LPC31_UART_LCR); /* Configure the MS and LS DLAB registers */ putreg32(div & UART_DLL_MASK, LPC31_UART_DLL); putreg32((div >> 8) & UART_DLL_MASK, LPC31_UART_DLM); regval &= ~UART_LCR_DLAB; putreg32(regval, LPC31_UART_LCR); /* Configure the Fractional Divider Register (FDR) */ putreg32((mulval << UART_FDR_MULVAL_SHIFT) | (divaddval << UART_FDR_DIVADDVAL_SHIFT), LPC31_UART_FDR); #else /* Set the Divisor Latch Access Bit (DLAB) to enable DLL/DLM access */ regval = getreg32(LPC31_UART_LCR); regval |= UART_LCR_DLAB; putreg32(regval, LPC31_UART_LCR); /* Configure the MS and LS DLAB registers */ putreg32(CONFIG_LPC31_UART_DIVISOR & UART_DLL_MASK, LPC31_UART_DLL); putreg32((CONFIG_LPC31_UART_DIVISOR >> 8) & UART_DLL_MASK, LPC31_UART_DLM); regval &= ~UART_LCR_DLAB; putreg32(regval, LPC31_UART_LCR); /* Configure the Fractional Divider Register (FDR) */ putreg32((CONFIG_LPC31_UART_MULVAL << UART_FDR_MULVAL_SHIFT) | (CONFIG_LPC31_UART_DIVADDVAL << UART_FDR_DIVADDVAL_SHIFT), LPC31_UART_FDR); #endif } /**************************************************************************** * Name: up_setup * * Description: * Configure the UART baud, bits, parity, fifos, etc. This method is called * the first time that the serial port is opened. * ****************************************************************************/ static int up_setup(struct uart_dev_s *dev) { #ifndef CONFIG_SUPPRESS_LPC31_UART_CONFIG struct up_dev_s *priv = (struct up_dev_s*)dev->priv; uint32_t regval; /* Clear fifos */ putreg32((UART_FCR_RXFIFORST|UART_FCR_TXFIFORST), LPC31_UART_FCR); /* Set trigger */ putreg32((UART_FCR_FIFOENABLE|UART_FCR_RXTRIGLEVEL_16), LPC31_UART_FCR); /* Set up the IER */ priv->ier = getreg32(LPC31_UART_IER); /* Set up the LCR */ regval = 0; #if CONFIG_UART_BITS == 5 regval |= UART_LCR_WDLENSEL_5BITS; #elif CONFIG_UART_BITS == 6 regval |= UART_LCR_WDLENSEL_6BITS; #elif CONFIG_UART_BITS == 7 regval |= UART_LCR_WDLENSEL_7BITS; #else regval |= UART_LCR_WDLENSEL_8BITS; #endif #if CONFIG_UART_2STOP > 0 regval |= UART_LCR_NSTOPBITS; #endif #if CONFIG_UART_PARITY == 1 regval |= UART_LCR_PAREN; #elif CONFIG_UART_PARITY == 2 regval |= (UART_LCR_PAREVEN|UART_LCR_PAREN); #endif putreg32(regval, LPC31_UART_LCR); /* Set the BAUD divisor */ up_configbaud(); /* Configure the FIFOs */ putreg32((UART_FCR_RXTRIGLEVEL_16|UART_FCR_TXFIFORST| UART_FCR_RXFIFORST|UART_FCR_FIFOENABLE), LPC31_UART_FCR); /* The NuttX serial driver waits for the first THRE interrrupt before * sending serial data... However, it appears that the lpc313x hardware * does not generate that interrupt until a transition from not-empty * to empty. So, the current kludge here is to send one NULL at * startup to kick things off. */ putreg32('\0', LPC31_UART_THR); #endif return OK; } /**************************************************************************** * Name: up_shutdown * * Description: * Disable the UART. This method is called when the serial port is closed * ****************************************************************************/ static void up_shutdown(struct uart_dev_s *dev) { struct up_dev_s *priv = (struct up_dev_s*)dev->priv; up_disableuartint(priv, NULL); } /**************************************************************************** * Name: up_attach * * Description: * Configure the UART to operation in interrupt driven mode. This method * is called when the serial port is opened. Normally, this is just after * he the setup() method is called, however, the serial console may operate in * in a non-interrupt driven mode during the boot phase. * * RX and TX interrupts are not enabled when by the attach method (unless * the hardware supports multiple levels of interrupt enabling). The RX and TX * and TX interrupts are not enabled until the txint() and rxint() methods * are called. * ****************************************************************************/ static int up_attach(struct uart_dev_s *dev) { int ret; /* Attach and enable the IRQ */ ret = irq_attach(LPC31_IRQ_UART, up_interrupt); if (ret == OK) { /* Enable the interrupt (RX and TX interrupts are still disabled * in the UART */ up_enable_irq(LPC31_IRQ_UART); } return ret; } /**************************************************************************** * Name: up_detach * * Description: * Detach UART interrupts. This method is called when the serial port is * closed normally just before the shutdown method is called. The * exception is the serial console which is never shutdown. * ****************************************************************************/ static void up_detach(struct uart_dev_s *dev) { up_disable_irq(LPC31_IRQ_UART); irq_detach(LPC31_IRQ_UART); } /**************************************************************************** * Name: up_interrupt * * Description: * This is the UART interrupt handler. It will be invoked when an * interrupt received on the UART irq. It should call uart_transmitchars * or uart_receivechar to perform the appropriate data transfers. * ****************************************************************************/ static int up_interrupt(int irq, void *context) { struct uart_dev_s *dev = &g_uartport; uint8_t status; int passes; /* Loop until there are no characters to be transferred or, * until we have been looping for a long time. */ for (passes = 0; passes < 256; passes++) { /* Get the current UART status and check for loop * termination conditions */ status = getreg32(LPC31_UART_IIR); /* The NO INTERRUPT should be zero if there are pending * interrupts */ if ((status & UART_IIR_NOINT) != 0) { /* Break out of the loop when there is no longer a pending * interrupt */ break; } /* Handle the interrupt by its interrupt ID field */ switch (status & UART_IIR_INTID_MASK) { /* Handle incoming, receive bytes (with or without timeout) */ case UART_IIR_INTID_RDA: /* Received Data Available */ case UART_IIR_INTID_TIMEOUT: /* Character time-out */ { uart_recvchars(dev); break; } /* Handle outgoing, transmit bytes */ case UART_IIR_INTID_THRE: /* Transmitter Holding Register empty */ { uart_xmitchars(dev); break; } /* Just clear modem status interrupts */ case UART_IIR_INTID_MS: /* Modem status */ { /* Read the modem status register (MSR) to clear */ status = getreg32(LPC31_UART_MSR); fvdbg("MSR: %02x\n", status); break; } /* Just clear any line status interrupts */ case UART_IIR_INTID_RLS: /* Receiver Line Status */ { /* Read the line status register (LSR) to clear */ status = getreg32(LPC31_UART_LSR); fvdbg("LSR: %02x\n", status); break; } /* There should be no other values */ default: { dbg("Unexpected IIR: %02x\n", status); break; } } } return OK; } /**************************************************************************** * Name: up_ioctl * * Description: * All ioctl calls will be routed through this method * ****************************************************************************/ static int up_ioctl(struct file *filep, int cmd, unsigned long arg) { struct inode *inode = filep->f_inode; struct uart_dev_s *dev = inode->i_private; int ret = OK; switch (cmd) { case TIOCSERGSTRUCT: { struct up_dev_s *user = (struct up_dev_s*)arg; if (!user) { ret = -EINVAL; } else { memcpy(user, dev, sizeof(struct up_dev_s)); } } break; case TIOCSBRK: /* BSD compatibility: Turn break on, unconditionally */ { irqstate_t flags = irqsave(); up_enablebreaks(); irqrestore(flags); } break; case TIOCCBRK: /* BSD compatibility: Turn break off, unconditionally */ { irqstate_t flags; flags = irqsave(); up_disablebreaks(); irqrestore(flags); } break; default: errno = ENOTTY; ret = ERROR; break; } return ret; } /**************************************************************************** * Name: up_receive * * Description: * Called (usually) from the interrupt level to receive one character from * the UART. Error bits associated with the receipt are provided in the * return 'status'. * ****************************************************************************/ static int up_receive(struct uart_dev_s *dev, uint32_t *status) { uint32_t rbr; *status = getreg32(LPC31_UART_LSR); rbr = getreg32(LPC31_UART_RBR); return rbr & 0xff; } /**************************************************************************** * Name: up_rxint * * Description: * Call to enable or disable RX interrupts * ****************************************************************************/ static void up_rxint(struct uart_dev_s *dev, bool enable) { struct up_dev_s *priv = (struct up_dev_s*)dev->priv; if (enable) { #ifndef CONFIG_SUPPRESS_SERIAL_INTS priv->ier |= UART_IER_RDAINTEN; #endif } else { priv->ier &= ~UART_IER_RDAINTEN; } putreg32(priv->ier, LPC31_UART_IER); } /**************************************************************************** * Name: up_rxavailable * * Description: * Return true if the receive fifo is not empty * ****************************************************************************/ static bool up_rxavailable(struct uart_dev_s *dev) { return ((getreg32(LPC31_UART_LSR) & UART_LSR_RDR) != 0); } /**************************************************************************** * Name: up_send * * Description: * This method will send one byte on the UART * ****************************************************************************/ static void up_send(struct uart_dev_s *dev, int ch) { putreg32((uint32_t)ch, LPC31_UART_THR); } /**************************************************************************** * Name: up_txint * * Description: * Call to enable or disable TX interrupts * ****************************************************************************/ static void up_txint(struct uart_dev_s *dev, bool enable) { struct up_dev_s *priv = (struct up_dev_s*)dev->priv; if (enable) { #ifndef CONFIG_SUPPRESS_SERIAL_INTS priv->ier |= UART_IER_THREINTEN; #endif } else { priv->ier &= ~UART_IER_THREINTEN; } putreg32(priv->ier, LPC31_UART_IER); } /**************************************************************************** * Name: up_txready * * Description: * Return true if the tranmsit fifo is not full * ****************************************************************************/ static bool up_txready(struct uart_dev_s *dev) { return ((getreg32(LPC31_UART_LSR) & UART_LSR_THRE) != 0); } /**************************************************************************** * Name: up_txempty * * Description: * Return true if the transmit fifo is empty * ****************************************************************************/ static bool up_txempty(struct uart_dev_s *dev) { return ((getreg32(LPC31_UART_LSR) & UART_LSR_TEMT) != 0); } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: up_earlyserialinit * * Description: * Performs the low level UART initialization early in debug so that the * serial console will be available during bootup (via up_putc). This must * be called before up_serialinit. * ****************************************************************************/ void up_earlyserialinit(void) { /* Enable UART system clock */ lpc31_enableclock(CLKID_UARTAPBCLK); lpc31_enableclock(CLKID_UARTUCLK); /* Disable UART interrupts */ up_disableuartint(g_uartport.priv, NULL); /* Configuration the serial console */ #if defined(CONFIG_UART_SERIAL_CONSOLE) g_uartport.isconsole = true; up_setup(&g_uartport); #endif } /**************************************************************************** * Name: up_serialinit * * Description: * Register serial console and serial ports. This assumes that * up_earlyserialinit was called previously. * ****************************************************************************/ void up_serialinit(void) { #if defined(CONFIG_UART_SERIAL_CONSOLE) (void)uart_register("/dev/console", &g_uartport); #endif (void)uart_register("/dev/ttyS0", &g_uartport); } /**************************************************************************** * Name: up_putc * * Description: * Provide priority, low-level access to support OS debug writes * ****************************************************************************/ int up_putc(int ch) { struct up_dev_s *priv = &g_uartpriv; uint8_t ier; /* Keep UART interrupts disabled so that we do not interfere with the * serial driver. */ up_disableuartint(priv, &ier); /* Check for LF */ if (ch == '\n') { /* Add CR */ up_lowputc('\r'); } /* Output the character */ up_lowputc(ch); up_restoreuartint(priv, ier); return ch; } #else /* USE_SERIALDRIVER */ /**************************************************************************** * Name: up_putc * * Description: * Provide priority, low-level access to support OS debug writes * ****************************************************************************/ int up_putc(int ch) { /* Check for LF */ if (ch == '\n') { /* Add CR */ up_lowputc('\r'); } /* Output the character */ up_lowputc(ch); return ch; } #endif /* USE_SERIALDRIVER */