diff options
Diffstat (limited to 'bsps/powerpc/mvme5500/GT64260/GT64260TWSI.c')
| -rw-r--r-- | bsps/powerpc/mvme5500/GT64260/GT64260TWSI.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/bsps/powerpc/mvme5500/GT64260/GT64260TWSI.c b/bsps/powerpc/mvme5500/GT64260/GT64260TWSI.c new file mode 100644 index 0000000000..6b5b46e511 --- /dev/null +++ b/bsps/powerpc/mvme5500/GT64260/GT64260TWSI.c @@ -0,0 +1,214 @@ +/* + * Two-Wire Serial Interface (TWSI) support for the GT64260 + */ + +/* + * Copyright (c) 2004, Brookhaven National Laboratory and + * Shuchen Kate Feng <feng1@bnl.gov> + * All rights reserved. + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution. + * + * See section 24:TWSI interface of "the GT-64260B System Controller + * for powerPc Processors Data Sheet". + * + * For full TWSI protocol description look in Philips Semiconductor + * TWSI spec. + * + * We need it to read out I2C devices used for the MVME5500 + * (eg. the memory SPD and VPD). + */ + +#include <libcpu/spr.h> /*registers.h included here for rtems_bsp_delay()*/ +#include <libcpu/io.h> +#include <rtems/bspIo.h> + +#include "bsp/gtreg.h" +#include "bsp/GT64260TWSI.h" + +#define MAX_LOOP 100 + +#define TWSI_DEBUG 0 + +static int TWSI_initFlg = 0; /* TWSI Initialization Flag */ + +void GT64260TWSIinit(void) +{ + if ( !TWSI_initFlg ) { +#if TWSI_DEBUG + printk("GT64260TWSIinit("); +#endif + outl( 0, TWSI_SFT_RST); /* soft reset */ + rtems_bsp_delay(1000); + + /* See 24.2.5 : Assume bus speed is 133MHZ + * Try to be close to the default frequency : 62.5KHZ + * value 0x2c: 69.27 KHz TWSI bus clock + */ + outl(0x2c, TWSI_BAUDE_RATE); + rtems_bsp_delay(1000); + + /* Set Acknowledge and enable TWSI in the Control register */ + outl(0x44, TWSI_CTRL); + rtems_bsp_delay(4000); + TWSI_initFlg = 1; +#if TWSI_DEBUG + printk(")\n"); +#endif + } +} + +/* return the interrupt flag */ +static int GT64260TWSIintFlag(void) +{ + unsigned int loop; + + for (loop = 0; loop < MAX_LOOP; loop++ ) { + /* Return 1 if the interrupt flag is set */ + if (inl(TWSI_CTRL) & TWSI_INTFLG) + return(1); + rtems_bsp_delay(1000); + } + return(0); +} + +int GT64260TWSIstop(void) +{ + +#if TWSI_DEBUG + printk("GT64260TWSIstop("); +#endif + + outl((inl(TWSI_CTRL) | TWSI_STOP), TWSI_CTRL); + rtems_bsp_delay(1000); + + /* Check if interrupt flag bit is set*/ + if (GT64260TWSIintFlag()) { + outl((inl( TWSI_CTRL) & ~TWSI_INTFLG), TWSI_CTRL); + rtems_bsp_delay(1000); +#if TWSI_DEBUG + printk(")\n"); +#endif + return(0); + } +#if TWSI_DEBUG + printk("NoIntFlag\n"); +#endif + return(-1); +} + +int GT64260TWSIstart(void) +{ + unsigned int loop; + unsigned int status; + +#if TWSI_DEBUG + printk("GT64260TWSIstart("); +#endif + /* Initialize the TWSI interface */ + GT64260TWSIinit(); + + /* set the start bit */ + outl((TWSI_START | TWSI_TWSIEN), TWSI_CTRL); + rtems_bsp_delay(1000); + + if (GT64260TWSIintFlag()) { + /* Check for completion of START sequence */ + for (loop = 0; loop<MAX_LOOP; loop++ ) { + /* if (start condition transmitted) || + * (repeated start condition transmitted ) + */ + if (((status= inl( TWSI_STATUS)) == 8) || (status == 0x10)) { +#if TWSI_DEBUG + printk(")"); +#endif + return(0); + } + rtems_bsp_delay(1000); + } + } + /* if loop ends or intFlag ==0 */ + GT64260TWSIstop(); + return(-1); +} + +int GT64260TWSIread(unsigned char * pData, int lastByte) +{ + unsigned int loop; + +#if TWSI_DEBUG + printk("GT64260TWSIread("); +#endif + /* Clear INTFLG and set ACK and ENABLE bits */ + outl((TWSI_ACK | TWSI_TWSIEN), TWSI_CTRL); + rtems_bsp_delay(1000); + + if (GT64260TWSIintFlag()) { + for (loop = 0; loop< MAX_LOOP; loop++) { + /* if Master received read data, acknowledge transmitted */ + if ( (inl( TWSI_STATUS) == 0x50)) { + *pData = (unsigned char) inl( TWSI_DATA); + rtems_bsp_delay(1500); + + /* Clear INTFLAG and set Enable bit only */ + if (lastByte) + outl(TWSI_TWSIEN, TWSI_CTRL); + rtems_bsp_delay(1500); +#if TWSI_DEBUG + printk(")\n"); +#endif + return(0); + } + rtems_bsp_delay(1000); + } /* end for */ + } + /* if loop ends or intFlag ==0 */ + GT64260TWSIstop(); + return(-1); +} + +/* do a TWSI write cycle on the TWSI bus*/ +int GT64260TWSIwrite(unsigned char Data) +{ + unsigned int loop; + unsigned int status; + +#if TWSI_DEBUG + printk("GT64260TWSIwrite("); +#endif + /* Write data into the TWSI data register */ + outl(((unsigned int) Data), TWSI_DATA); + rtems_bsp_delay(1000); + + /* Clear INTFLG in the control register to drive data onto TWSI bus */ + outl(0, TWSI_CTRL); + rtems_bsp_delay(1000); + + if (GT64260TWSIintFlag() ) { + for (loop = 0; loop< MAX_LOOP; loop++) { + rtems_bsp_delay(1000); + /* if address + write bit transmitted, acknowledge not received */ + if ( (status = inl( TWSI_STATUS)) == 0x20) { + /* No device responding, generate STOP and return -1 */ + printk("no device responding\n"); + GT64260TWSIstop(); + return(-1); + } + /* if (address + write bit transmitted, acknowledge received) + * (Master transmmitted data byte, acknowledge received) + * (address + read bit transmitted, acknowledge received) + */ + if ((status == 0x18)||(status == 0x28)||(status == 0x40)) { +#if TWSI_DEBUG + printk(")\n"); +#endif + return(0); + } + rtems_bsp_delay(1000); + } /* end for */ + } + printk("No correct status, timeout\n"); + GT64260TWSIstop(); + return(-1); +} |