/* primeCellSio.c - ARM AMBA UART tty driver *//* * Copyright (c) 1997-2005 Wind River Systems, Inc. * * The right to copy, distribute or otherwise make use of this software * may be licensed only pursuant to the terms of an applicable Wind River * license agreement. *//*modification history--------------------01e,08jul05,h_k  added minimal poll driver feature.01d,02may05,mdo  SPR#10793001c,21feb00,jpd  renamed primecell... symbols to primeCell...01b,25jan00,jpd  renamed primeCellSio.c.01a,10nov99,ajb  copied from ambaSio.c, adding support for 1 interrupt per UART.*//*DESCRIPTIONThis is the device driver for the Advanced RISC Machines (ARM) AMBAUART. This is a generic design of UART used within a number of chipscontaining (or for use with) ARM CPUs such as in the Digital Semiconductor21285 chip as used in the EBSA-285 BSP.This design contains a universal asynchronous receiver/transmitter, abaud-rate generator, and an InfraRed Data Association (IrDa) SerialInfraRed (SiR) protocol encoder. The Sir encoder is not supported bythis driver. The UART contains two 16-entry deep FIFOs for receive andtransmit: if a framing, overrun or parity error occurs duringreception, the appropriate error bits are stored in the receive FIFOalong with the received data. The FIFOs can be programmed to be onebyte deep only, like a conventional UART with double buffering, but theonly mode of operation supported is with the FIFOs enabled.The UART design does not support the modem control output signals: DTR,RI and RTS. Moreover, the implementation in the 21285 chip does notsupport the modem control inputs: DCD, CTS and DSR.The UART design can generate four interrupts: Rx, Tx, modem statuschange and a UART disabled interrupt (which is asserted when a startbit is detected on the receive line when the UART is disabled). Theimplementation in the 21285 chip has only two interrupts: Rx and Tx,but the Rx interrupt is a combination of the normal Rx interrupt statusand the UART disabled interrupt status.Only asynchronous serial operation is supported by the UART whichsupports 5 to 8 bit word lengths with or without parity and withone or two stop bits. The only serial word format supported by thedriver is 8 data bits, 1 stop bit, no parity,  The default baud rate isdetermined by the BSP by filling in the AMBA_CHAN structure beforecalling ambaDevInit().The exact baud rates supported by this driver will depend on thecrystal fitted (and consequently the input clock to the baud-rategenerator), but in general, baud rates from about 300 to about 115200are possible.In theory, any number of UART channels could be implemented within achip. This driver has been designed to cope with an arbitrary number ofchannels, but at the time of writing, has only ever been tested withone channel.DATA STRUCTURESAn AMBA_CHAN data structure is used to describe each channel, thisstructure is described in h/drv/sio/ambaSio.h.CALLBACKSServicing a "transmitter ready" interrupt involves making a callback toa higher level library in order to get a character to transmit.  Bydefault, this driver installs dummy callback routines which do nothing.A higher layer library that wants to use this driver (e.g. ttyDrv)will install its own callback routine using the SIO_INSTALL_CALLBACKioctl command.  Likewise, a receiver interrupt handler makes a callbackto pass the character to the higher layer library. MODESThis driver supports both polled and interrupt modes.USAGEThe driver is typically only called by the BSP. The directly callableroutines in this modules are ambaDevInit(), ambaIntTx() andambaIntRx().The BSP's sysHwInit() routine typically calls sysSerialHwInit(), whichinitialises the hardware-specific fields in the AMBA_CHAN structure(e.g. register I/O addresses etc) before calling ambaDevInit() whichresets the device and installs the driver function pointers.  Afterthis the UART will be enabled and ready to generate interrupts, butthose interrupts will be disabled in the interrupt controller.The following example shows the first parts of the initialisation:\cs#include "primeCellSio.h"LOCAL AMBA_CHAN ambaChan[N_AMBA_UART_CHANS];void sysSerialHwInit (void)    {    int i;    for (i = 0; i < N_AMBA_UART_CHANS; i++)	{	ambaChan[i].regs = devParas[i].baseAdrs;	ambaChan[i].baudRate = CONSOLE_BAUD_RATE;	ambaChan[i].xtal = UART_XTAL_FREQ; 	ambaChan[i].levelRx = devParas[i].intLevelRx;	ambaChan[i].levelTx = devParas[i].intLevelTx;	/@	 * Initialise driver functions, getTxChar, putRcvChar and	 * channelMode, then initialise UART	 @/	ambaDevInit(&ambaChan[i]);	}    }\ceThe BSP's sysHwInit2() routine typically calls sysSerialHwInit2(),which connects the chips interrupts via intConnect() (the twointerrupts `ambaIntTx' and `ambaIntRx') and enables those interrupts,as shown in the following example:\csvoid sysSerialHwInit2 (void)    {    /@ connect and enable Rx interrupt @/    (void) intConnect (INUM_TO_IVEC(devParas[0].vectorRx),		       ambaIntRx, (int) &ambaChan[0]);    intEnable (devParas[0].intLevelRx);    /@ connect Tx interrupt @/    (void) intConnect (INUM_TO_IVEC(devParas[0].vectorTx),		       ambaIntTx, (int) &ambaChan[0]);    /@     * There is no point in enabling the Tx interrupt, as it will     * interrupt immediately and then be disabled.     @/    }\ceBSPBy convention all the BSP-specific serial initialisation is performedin a file called sysSerial.c, which is #include'ed by sysLib.c.sysSerial.c implements at least four functions, sysSerialHwInit()sysSerialHwInit2(), sysSerialChanGet(), and sysSerialReset(). The firsttwo have been described above, the others work as follows:sysSerialChanGet is called by usrRoot to get the serial channeldescriptor associated with a serial channel number. The routine takes asingle parameter which is a channel number ranging between zero andNUM_TTY. It returns a pointer to the corresponding channel descriptor,SIO_CHAN *, which is just the address of the AMBA_CHAN structure. sysSerialReset is called from sysToMonitor() and should reset theserial devices to an inactive state (prevent them from generating anyinterrupts).INCLUDE FILES:drv/sio/ambaSio.h sioLib.hSEE ALSO:\tb Advanced RISC Machines AMBA UART (AP13) Data Sheet, \tb Digital Semiconductor 21285 Core Logic for SA-110 Microprocessor Data Sheet,"\tb Digital Semiconductor EBSA-285 Evaluation Board Reference Manual. */#include <vxWorks.h>#include <intLib.h>#include <errnoLib.h>#include <errno.h>#include <sioLib.h>#include "primeCellSio.h"/* local defines  */#ifndef AMBA_UART_REG#define AMBA_UART_REG(pChan, reg) \	(*(volatile UINT32 *)((UINT32)(pChan)->regs + (reg)))#endif#ifndef AMBA_UART_REG_READ#define AMBA_UART_REG_READ(pChan, reg, result) \	(result) = (AMBA_UART_REG(pChan, reg))#endif#ifndef AMBA_UART_REG_WRITE#define AMBA_UART_REG_WRITE(pChan, reg, data) \	(AMBA_UART_REG(pChan, reg)) = (data)#endif#ifndef AMBA_UART_REG_BIT_SET#define AMBA_UART_REG_BIT_SET(pChan, reg, data) \	(AMBA_UART_REG(pChan, reg)) |= (data)#endif#ifndef AMBA_UART_REG_BIT_CLR#define AMBA_UART_REG_BIT_CLR(pChan, reg, data) \	(AMBA_UART_REG(pChan, reg)) &= ~(data)#endif/* locals *//* function prototypes */LOCAL STATUS ambaDummyCallback (void);LOCAL void   ambaInitChannel (AMBA_CHAN * pChan);LOCAL STATUS ambaIoctl (SIO_CHAN * pSioChan, int request, int arg);#ifdef	INCLUDE_TTY_DEVLOCAL int    ambaTxStartup (SIO_CHAN * pSioChan);LOCAL int    ambaCallbackInstall (SIO_CHAN * pSioChan, int callbackType,			       STATUS (*callback)(), void * callbackArg);#endif	/* INCLUDE_TTY_DEV */LOCAL int    ambaPollInput (SIO_CHAN * pSioChan, char *);LOCAL int    ambaPollOutput (SIO_CHAN * pSioChan, char);/* driver functions */LOCAL SIO_DRV_FUNCS ambaSioDrvFuncs =    {    (int (*)())                 ambaIoctl,#ifdef	INCLUDE_TTY_DEV    (int (*)())                 ambaTxStartup,    (int (*)())                 ambaCallbackInstall,#else	/* INCLUDE_TTY_DEV */    (int (*)())                 NULL,    (int (*)())                 NULL,#endif	/* INCLUDE_TTY_DEV */    (int (*)())                 ambaPollInput,    (int (*)(SIO_CHAN *,char))  ambaPollOutput    };/********************************************************************************* ambaDummyCallback - dummy callback routine.** This routine does nothing.** RETURNS: ERROR, always.** ERRNO*/LOCAL STATUS ambaDummyCallback (void)    {    return ERROR;    }/********************************************************************************* primeCellSioDevInit - initialise an AMBA channel** This routine initialises some SIO_CHAN function pointers and then resets* the chip to a quiescent state.  Before this routine is called, the BSP* must already have initialised all the device addresses, etc. in the* AMBA_CHAN structure.** RETURNS: N/A** ERRNO*/void primeCellSioDevInit    (    AMBA_CHAN *	pChan	/* ptr to AMBA_CHAN describing this channel */    )    {    int oldlevel = intLock();    /* initialise the driver function pointers in the SIO_CHAN */    pChan->sio.pDrvFuncs = &ambaSioDrvFuncs;    /* set the non BSP-specific constants */    pChan->getTxChar = ambaDummyCallback;    pChan->putRcvChar = ambaDummyCallback;    pChan->channelMode = 0;    /* undefined */    /* initialise the chip */    ambaInitChannel (pChan);    intUnlock (oldlevel);    }/********************************************************************************* ambaInitChannel - initialise UART** This routine performs hardware initialisation of the UART channel.** RETURNS: N/A** ERRNO*/LOCAL void ambaInitChannel    (    AMBA_CHAN *	pChan	/* ptr to AMBA_CHAN describing this channel */    )    {    int		i;    UINT32	discard;    /* Fill Tx FIFO with nulls (data sheet specifies this) */    for (i = 0; i < 16; i++)        AMBA_UART_REG_WRITE(pChan, UARTDR, 0);    /* Program UART control register */    AMBA_UART_REG_WRITE(pChan, UARTCON, 0);    AMBA_UART_REG_WRITE(pChan, UARTCON, UART_ENABLE);    /* Ensure that only Receive ints are generated. */    AMBA_UART_REG_BIT_CLR(pChan, 			  UARTCON, 			  UART_RTIE | UART_TIE | 			  UART_RIE | UART_MSIE );    AMBA_UART_REG_BIT_SET(pChan, UARTCON, UART_RIE | UART_RTIE);    /* Set baud rate divisor */    AMBA_UART_REG_WRITE(pChan, L_UBRLCR,		    (pChan->xtal / (16 * pChan->baudRate) - 1) & 0xFF);    AMBA_UART_REG_WRITE(pChan, M_UBRLCR,		    ((pChan->xtal / (16 * pChan->baudRate) - 1) >> 8) & 0xF);    /*     * Set word format, enable FIFOs: set 8 bits, 1 stop bit, no parity.     * This also latches the writes to the two (sub)registers above.     */    AMBA_UART_REG_WRITE(pChan, H_UBRLCR,	(UINT8)(WORD_LEN_8 | ONE_STOP | PARITY_NONE | FIFO_ENABLE));     /* Clear Rx FIFO (data sheet specifies this) */    for (i = 0; i < 16; i++)        AMBA_UART_REG_READ(pChan, RXSTAT, discard);    }/********************************************************************************* ambaIoctl - special device control** This routine handles the IOCTL messages from the user.** RETURNS: OK on success** ERRNO:  ENOSYS on unsupported request, EIO on failed request.*/LOCAL STATUS ambaIoctl    (    SIO_CHAN *	pSioChan,	/* ptr to SIO_CHAN describing this channel */    int		request,	/* request code */    int		arg		/* some argument */    )    {    int		oldlevel;	/* current interrupt level mask */    STATUS	status;		/* status to return */    UINT32	brd;		/* baud rate divisor */    AMBA_CHAN * pChan = (AMBA_CHAN *)pSioChan;    status = OK;	/* preset to return OK */    switch (request)        {        case SIO_BAUD_SET:            /*             * Set the baud rate. Return EIO for an invalid baud rate, or             * OK on success.             */            /*             * baudrate divisor must be non-zero and must fit in a 12-bit             * register.