diff options
Diffstat (limited to 'cpukit/libi2c/libi2c.c')
| -rw-r--r-- | cpukit/libi2c/libi2c.c | 778 |
1 files changed, 778 insertions, 0 deletions
diff --git a/cpukit/libi2c/libi2c.c b/cpukit/libi2c/libi2c.c new file mode 100644 index 0000000000..1f88968aab --- /dev/null +++ b/cpukit/libi2c/libi2c.c @@ -0,0 +1,778 @@ +/* $Id$ */ + +/* libi2c Implementation */ + +/* + * Authorship + * ---------- + * This software was created by + * Till Straumann <strauman@slac.stanford.edu>, 2005, + * Stanford Linear Accelerator Center, Stanford University. + * + * Acknowledgement of sponsorship + * ------------------------------ + * This software was produced by + * the Stanford Linear Accelerator Center, Stanford University, + * under Contract DE-AC03-76SFO0515 with the Department of Energy. + * + * Government disclaimer of liability + * ---------------------------------- + * Neither the United States nor the United States Department of Energy, + * nor any of their employees, makes any warranty, express or implied, or + * assumes any legal liability or responsibility for the accuracy, + * completeness, or usefulness of any data, apparatus, product, or process + * disclosed, or represents that its use would not infringe privately owned + * rights. + * + * Stanford disclaimer of liability + * -------------------------------- + * Stanford University makes no representations or warranties, express or + * implied, nor assumes any liability for the use of this software. + * + * Stanford disclaimer of copyright + * -------------------------------- + * Stanford University, owner of the copyright, hereby disclaims its + * copyright and all other rights in this software. Hence, anyone may + * freely use it for any purpose without restriction. + * + * Maintenance of notices + * ---------------------- + * In the interest of clarity regarding the origin and status of this + * SLAC software, this and all the preceding Stanford University notices + * are to remain affixed to any copy or derivative of this software made + * or distributed by the recipient and are to be affixed to any copy of + * software made or distributed by the recipient that contains a copy or + * derivative of this software. + * + * ------------------ SLAC Software Notices, Set 4 OTT.002a, 2004 FEB 03 + */ +/* + * adaptations to also handle SPI devices + * by Thomas Doerfler, embedded brains GmbH, Puchheim, Germany + */ +#if HAVE_CONFIG_H +#include "config.h" +#endif + +#include <string.h> +#include <stdio.h> +#include <stdlib.h> +#include <errno.h> +#include <assert.h> +#include <stdarg.h> + +#include <rtems.h> +#include <rtems/error.h> +#include <rtems/bspIo.h> +#include <rtems/libio.h> + +#include <rtems/libi2c.h> + +#define DRVNM "libi2c: " + +#define MAX_NO_BUSSES 8 /* Also limited by the macro building minor numbers */ +#define MAX_NO_DRIVERS 16 /* Number of high level drivers we support */ + +#define MINOR2ADDR(minor) ((minor)&((1<<10)-1)) +#define MINOR2BUS(minor) (((minor)>>10)&7) +#define MINOR2DRV(minor) ((minor)>>13) + +/* Check the 'minor' argument, i.e., verify that + * we have a driver connected + */ +#define DECL_CHECKED_BH(b, bh, m, s)\ + unsigned b = MINOR2BUS(m); \ + rtems_libi2c_bus_t *bh; \ + if ( b >= MAX_NO_BUSSES || 0 == (bh=busses[b].bush) ) { \ + return s RTEMS_INVALID_NUMBER; \ + } + +#define DECL_CHECKED_DRV(d, b, m) \ + unsigned d = MINOR2DRV(m); \ + unsigned b = MINOR2BUS(m); \ + if ( b >= MAX_NO_BUSSES || 0 == busses[b].bush \ + || d > MAX_NO_DRIVERS || (d && 0 == drvs[d-1].drv )) {\ + return RTEMS_INVALID_NUMBER; \ + } + +#define DISPATCH(rval, entry, dflt) \ + do { \ + const rtems_driver_address_table *ops = drvs[--drv].drv->ops; \ + rval = ops->entry ? ops->entry(major,minor,arg) : dflt; \ + } while (0) + + +rtems_device_major_number rtems_libi2c_major; + +static bool is_initialized = false; + +static struct i2cbus +{ + rtems_libi2c_bus_t *bush; + volatile rtems_id mutex; /* lock this across start -> stop */ + volatile bool started; + char *name; +} busses[MAX_NO_BUSSES] = { { NULL, RTEMS_ID_NONE, false, NULL } }; + +static struct +{ + rtems_libi2c_drv_t *drv; +} drvs[MAX_NO_DRIVERS] = { { NULL } }; + +static rtems_id libmutex = RTEMS_ID_NONE; + +#define LOCK(m) assert(!rtems_semaphore_obtain((m), RTEMS_WAIT, RTEMS_NO_TIMEOUT)) +#define UNLOCK(m) rtems_semaphore_release((m)) + +#define LIBLOCK() LOCK(libmutex) +#define LIBUNLOCK() UNLOCK(libmutex) + +#define MUTEX_ATTS \ + ( RTEMS_PRIORITY \ + | RTEMS_BINARY_SEMAPHORE \ + |RTEMS_INHERIT_PRIORITY \ + |RTEMS_NO_PRIORITY_CEILING \ + |RTEMS_LOCAL ) + +/* During early stages of life, stdio is not available */ + +static void +safe_printf (const char *fmt, ...) +{ +va_list ap; + + va_start(ap, fmt); + if ( _System_state_Is_up( _System_state_Get() ) ) + vfprintf( stderr, fmt, ap ); + else + vprintk( fmt, ap ); + va_end(ap); +} + +static rtems_status_code +mutexCreate (rtems_name nm, rtems_id *pm) +{ + rtems_status_code sc; + + if (RTEMS_SUCCESSFUL != + (sc = rtems_semaphore_create (nm, 1, MUTEX_ATTS, 0, pm))) { + if ( _System_state_Is_up( _System_state_Get() ) ) + rtems_error (sc, DRVNM "Unable to create mutex\n"); + else + printk (DRVNM "Unable to create mutex (status code %i)\n", sc); + } + return sc; +} + +/* Lock a bus avoiding to have a mutex, which is mostly + * unused, hanging around all the time. We just create + * and delete it on the fly... + * + * ASSUMES: argument checked by caller + */ + +static void +lock_bus (int busno) +{ + struct i2cbus *bus = &busses[busno]; + + if (bus->mutex == RTEMS_ID_NONE) { + /* + * Nobody is holding the bus mutex - it's not there. Create it on the fly. + */ + LIBLOCK (); + if (bus->mutex == RTEMS_ID_NONE) { + rtems_id m = RTEMS_ID_NONE; + rtems_status_code sc = mutexCreate ( + rtems_build_name ('i', '2', 'c', '0' + busno), + &m + ); + if (sc != RTEMS_SUCCESSFUL) { + LIBUNLOCK (); + rtems_panic (DRVNM "Unable to create bus lock"); + return; + } + bus->mutex = m; + } + LIBUNLOCK (); + } + + /* Now lock this bus */ + LOCK (bus->mutex); +} + +static void +unlock_bus (int busno) +{ + struct i2cbus *bus = &busses[busno]; + UNLOCK (bus->mutex); +} + +/* Note that 'arg' is always passed in as NULL */ +rtems_status_code +rtems_i2c_init (rtems_device_major_number major, rtems_device_minor_number minor, + void *arg) +{ + rtems_status_code rval; + /* No busses or drivers can be registered at this point; + * avoid the macro aborting with an error + DECL_CHECKED_DRV (drv, busno, minor) + */ + + rval = mutexCreate (rtems_build_name ('l', 'I', '2', 'C'), &libmutex); + + if ( RTEMS_SUCCESSFUL == rval ) { + is_initialized = true; + rtems_libi2c_major = major; + } else { + libmutex = RTEMS_ID_NONE; + } + return rval; +} + +rtems_status_code +rtems_i2c_open (rtems_device_major_number major, rtems_device_minor_number minor, + void *arg) +{ + rtems_status_code rval; + DECL_CHECKED_DRV (drv, busno, minor) + + if (0 == drv) { + rval = RTEMS_SUCCESSFUL; + } else { + DISPATCH (rval, open_entry, RTEMS_SUCCESSFUL); + } + return rval; +} + +rtems_status_code +rtems_i2c_close (rtems_device_major_number major, rtems_device_minor_number minor, + void *arg) +{ + rtems_status_code rval; + DECL_CHECKED_DRV (drv, busno, minor) + + if (0 == drv) { + rval = RTEMS_SUCCESSFUL; + } else { + DISPATCH (rval, close_entry, RTEMS_SUCCESSFUL); + } + return rval; +} + +rtems_status_code +rtems_i2c_read (rtems_device_major_number major, rtems_device_minor_number minor, + void *arg) +{ + int rval; /* int so we can check for negative value */ + rtems_libio_rw_args_t *rwargs = arg; + DECL_CHECKED_DRV (drv, busno, minor) + + if (0 == rwargs->count) { + rwargs->bytes_moved = 0; + return RTEMS_SUCCESSFUL; + } + + if (0 == drv) { + rval = + rtems_libi2c_start_read_bytes (minor, (unsigned char *) rwargs->buffer, + rwargs->count); + if (rval >= 0) { + rwargs->bytes_moved = rval; + rtems_libi2c_send_stop (minor); + rval = RTEMS_SUCCESSFUL; + } else { + rval = -rval; + } + } else { + DISPATCH (rval, read_entry, RTEMS_NOT_IMPLEMENTED); + } + return rval; +} + +rtems_status_code +rtems_i2c_write (rtems_device_major_number major, rtems_device_minor_number minor, + void *arg) +{ + int rval; /* int so we can check for negative value */ + rtems_libio_rw_args_t *rwargs = arg; + DECL_CHECKED_DRV (drv, busno, minor) + + if (0 == rwargs->count) { + rwargs->bytes_moved = 0; + return RTEMS_SUCCESSFUL; + } + + if (0 == drv) { + rval = + rtems_libi2c_start_write_bytes (minor, (unsigned char *) rwargs->buffer, + rwargs->count); + if (rval >= 0) { + rwargs->bytes_moved = rval; + rtems_libi2c_send_stop (minor); + rval = RTEMS_SUCCESSFUL; + } else { + rval = -rval; + } + } else { + DISPATCH (rval, write_entry, RTEMS_NOT_IMPLEMENTED); + } + return rval; +} + +rtems_status_code +rtems_i2c_ioctl (rtems_device_major_number major, rtems_device_minor_number minor, + void *arg) +{ + rtems_status_code rval; + DECL_CHECKED_DRV (drv, busno, minor) + + if (0 == drv) { + rval = RTEMS_NOT_IMPLEMENTED; + } else { + DISPATCH (rval, control_entry, RTEMS_NOT_IMPLEMENTED); + } + return rval; +} + + +/* Our ops just dispatch to the registered drivers */ +const rtems_driver_address_table rtems_libi2c_io_ops = { + initialization_entry: rtems_i2c_init, + open_entry: rtems_i2c_open, + close_entry: rtems_i2c_close, + read_entry: rtems_i2c_read, + write_entry: rtems_i2c_write, + control_entry: rtems_i2c_ioctl, +}; + +int +rtems_libi2c_initialize (void) +{ + rtems_status_code sc; + + if (is_initialized) { + /* + * already called before? then skip this step + */ + return 0; + } + + /* rtems_io_register_driver does NOT currently check nor report back + * the return code of the 'init' operation, so we cannot + * rely on return code since it may seem OK even if the driver 'init; + * op failed. + * Let 'init' handle 'is_initialized'... + */ + sc = rtems_io_register_driver (0, &rtems_libi2c_io_ops, &rtems_libi2c_major); + if (RTEMS_SUCCESSFUL != sc) { + safe_printf( + DRVNM "Claiming driver slot failed (rtems status code %i)\n", + sc); + if (libmutex != RTEMS_ID_NONE) { + rtems_semaphore_delete (libmutex); + } + libmutex = RTEMS_ID_NONE; + is_initialized = false; + return -1; + } + + return 0; +} + +int +rtems_libi2c_register_bus (const char *name, rtems_libi2c_bus_t * bus) +{ + int i; + rtems_status_code err; + size_t length = (name ? strlen (name) + 1 : 20); + char *nmcpy = malloc(length); + char tmp, *chpt; + struct stat sbuf; + + if (nmcpy == NULL) { + safe_printf ( DRVNM "No memory\n"); + return -RTEMS_NO_MEMORY; + } + + strncpy (nmcpy, name ? name : "/dev/i2c", length); + + /* check */ + if ('/' != *nmcpy) { + safe_printf ( DRVNM "Bad name: must be an absolute path starting with '/'\n"); + free( nmcpy ); + return -RTEMS_INVALID_NAME; + } + /* file must not exist */ + if (!stat (nmcpy, &sbuf)) { + safe_printf ( DRVNM "Bad name: file exists already\n"); + free( nmcpy ); + return -RTEMS_INVALID_NAME; + } + + /* we already verified that there is at least one '/' */ + chpt = strrchr (nmcpy, '/') + 1; + tmp = *chpt; + *chpt = 0; + i = stat (nmcpy, &sbuf); + *chpt = tmp; + if (i) { + safe_printf ( DRVNM "Get %s status failed: %s\n", + nmcpy, strerror(errno)); + free( nmcpy ); + return -RTEMS_INVALID_NAME; + } + /* should be a directory since name terminates in '/' */ + + + if (libmutex == RTEMS_ID_NONE) { + safe_printf ( DRVNM "Library not initialized\n"); + free( nmcpy ); + return -RTEMS_NOT_DEFINED; + } + + if (bus == NULL || bus->size < sizeof (*bus)) { + safe_printf ( DRVNM "No bus-ops or size too small -- misconfiguration?\n"); + free( nmcpy ); + return -RTEMS_NOT_CONFIGURED; + } + + LIBLOCK (); + for (i = 0; i < MAX_NO_BUSSES; i++) { + if (!busses[i].bush) { + /* found a free slot */ + busses[i].bush = bus; + busses[i].mutex = RTEMS_ID_NONE; + busses[i].started = false; + + if (!name) + sprintf (nmcpy + strlen (nmcpy), "%i", i); + + if ((err = busses[i].bush->ops->init (busses[i].bush))) { + /* initialization failed */ + i = -err; + } else { + busses[i].name = nmcpy;; + nmcpy = 0; + } + + break; + } + } + LIBUNLOCK (); + + if (i >= MAX_NO_BUSSES) { + i = -RTEMS_TOO_MANY; + } + + free (nmcpy); + + return i; +} + +static int +not_started (int busno) +{ + int rval; + lock_bus (busno); + rval = !busses[busno].started; + unlock_bus (busno); + return rval; +} + +rtems_status_code +rtems_libi2c_send_start (rtems_device_minor_number minor) +{ + int rval; + DECL_CHECKED_BH (busno, bush, minor, +) + + lock_bus (busno); + rval = bush->ops->send_start (bush); + + /* if this failed or is not the first start, unlock */ + if (rval || busses[busno].started) { + /* HMM - what to do if the 1st start failed ? + * try to reset... + */ + if (!busses[busno].started) { + /* just in case the bus driver fiddles with errno */ + int errno_saved = errno; + bush->ops->init (bush); + errno = errno_saved; + } else if (rval) { + /* failed restart */ + rtems_libi2c_send_stop (minor); + } + unlock_bus (busno); + } else { + /* successful 1st start; keep bus locked until stop is sent */ + busses[busno].started = true; + } + return rval; +} + +rtems_status_code +rtems_libi2c_send_stop (rtems_device_minor_number minor) +{ + rtems_status_code rval; + DECL_CHECKED_BH (busno, bush, minor, +) + + if (not_started (busno)) + return RTEMS_NOT_OWNER_OF_RESOURCE; + + rval = bush->ops->send_stop (bush); + + busses[busno].started = false; + + unlock_bus (busno); + return rval; +} + +rtems_status_code +rtems_libi2c_send_addr (rtems_device_minor_number minor, int rw) +{ + rtems_status_code sc; + DECL_CHECKED_BH (busno, bush, minor, +) + + if (not_started (busno)) + return RTEMS_NOT_OWNER_OF_RESOURCE; + + sc = bush->ops->send_addr (bush, MINOR2ADDR (minor), rw); + if (RTEMS_SUCCESSFUL != sc) + rtems_libi2c_send_stop (minor); + return sc; +} + +int +rtems_libi2c_read_bytes (rtems_device_minor_number minor, + unsigned char *bytes, + int nbytes) +{ + int sc; + DECL_CHECKED_BH (busno, bush, minor, -) + + if (not_started (busno)) + return -RTEMS_NOT_OWNER_OF_RESOURCE; + + sc = bush->ops->read_bytes (bush, bytes, nbytes); + if (sc < 0) + rtems_libi2c_send_stop (minor); + return sc; +} + +int +rtems_libi2c_write_bytes (rtems_device_minor_number minor, + const unsigned char *bytes, + int nbytes) +{ + int sc; + DECL_CHECKED_BH (busno, bush, minor, -) + + if (not_started (busno)) + return -RTEMS_NOT_OWNER_OF_RESOURCE; + + sc = bush->ops->write_bytes (bush, (unsigned char *)bytes, nbytes); + if (sc < 0) + rtems_libi2c_send_stop (minor); + return sc; +} + +int +rtems_libi2c_ioctl (rtems_device_minor_number minor, + int cmd, + ...) +{ + va_list ap; + int sc = 0; + void *args; + bool is_started = false; + DECL_CHECKED_BH (busno, bush, minor, -) + + va_start(ap, cmd); + args = va_arg(ap, void *); + + switch(cmd) { + /* + * add ioctls defined for this level here: + */ + + case RTEMS_LIBI2C_IOCTL_GET_DRV_T: + /* + * query driver table entry + */ + *(rtems_libi2c_drv_t **)args = (drvs[MINOR2DRV(minor)-1].drv); + break; + + case RTEMS_LIBI2C_IOCTL_START_TFM_READ_WRITE: + if (not_started (busno)) { + va_end(ap); + return -RTEMS_NOT_OWNER_OF_RESOURCE; + } + + /* + * address device, then set transfer mode and perform read_write transfer + */ + /* + * perform start/address + */ + if (sc == 0) { + sc = rtems_libi2c_send_start (minor); + is_started = (sc == 0); + } + /* + * set tfr mode + */ + if (sc == 0) { + sc = bush->ops->ioctl + (bush, + RTEMS_LIBI2C_IOCTL_SET_TFRMODE, + &((rtems_libi2c_tfm_read_write_t *)args)->tfr_mode); + } + /* + * perform read_write + */ + if (sc == 0) { + sc = bush->ops->ioctl + (bush, + RTEMS_LIBI2C_IOCTL_READ_WRITE, + &((rtems_libi2c_tfm_read_write_t *)args)->rd_wr); + } + if ((sc < 0) && (is_started)) { + rtems_libi2c_send_stop (minor); + } + break; + default: + sc = bush->ops->ioctl (bush, cmd, args); + break; + } + va_end(ap); + return sc; +} + +static int +do_s_rw (rtems_device_minor_number minor, + unsigned char *bytes, + int nbytes, + int rw) +{ + rtems_status_code sc; + rtems_libi2c_bus_t *bush; + int status; + + if ((sc = rtems_libi2c_send_start (minor))) + return -sc; + + /* at this point, we hold the bus and are sure the minor number is valid */ + bush = busses[MINOR2BUS (minor)].bush; + + if ((sc = bush->ops->send_addr (bush, MINOR2ADDR (minor), rw))) { + rtems_libi2c_send_stop (minor); + return -sc; + } + + if (rw) + status = bush->ops->read_bytes (bush, bytes, nbytes); + else + status = bush->ops->write_bytes (bush, bytes, nbytes); + + if (status < 0) { + rtems_libi2c_send_stop (minor); + } + return status; +} + +int +rtems_libi2c_start_read_bytes (rtems_device_minor_number minor, + unsigned char *bytes, + int nbytes) +{ + return do_s_rw (minor, bytes, nbytes, 1); +} + +int +rtems_libi2c_start_write_bytes (rtems_device_minor_number minor, + const unsigned char *bytes, + int nbytes) +{ + return do_s_rw (minor, (unsigned char *)bytes, nbytes, 0); +} + +int +rtems_libi2c_register_drv (const char *name, rtems_libi2c_drv_t * drvtbl, + unsigned busno, unsigned i2caddr) +{ + int i; + rtems_status_code err; + rtems_device_minor_number minor; + + if (libmutex == RTEMS_ID_NONE) { + safe_printf ( DRVNM "Library not initialized\n"); + return -RTEMS_NOT_DEFINED; + } + + if (name && strchr (name, '/')) { + safe_printf ( DRVNM "Invalid name: '%s' -- must not contain '/'\n", name); + return -RTEMS_INVALID_NAME; + } + + if (busno >= MAX_NO_BUSSES || !busses[busno].bush || i2caddr >= 1 << 10) { + errno = EINVAL; + return -RTEMS_INVALID_NUMBER; + } + + if (drvtbl == NULL || drvtbl->size < sizeof (*drvtbl)) { + safe_printf ( DRVNM "No driver table or size too small -- misconfiguration?\n"); + return -RTEMS_NOT_CONFIGURED; + } + + /* allocate slot */ + LIBLOCK (); + for (i = 0; i < MAX_NO_DRIVERS; i++) { + /* driver # 0 is special, it is the built-in raw driver */ + if (!drvs[i].drv) { + char *str; + dev_t dev; + uint32_t mode; + + /* found a free slot; encode slot + 1 ! */ + minor = ((i + 1) << 13) | RTEMS_LIBI2C_MAKE_MINOR (busno, i2caddr); + + if (name) { + size_t length = strlen (busses[busno].name) + strlen (name) + 2; + str = malloc (length); + snprintf (str, length, "%s.%s", busses[busno].name, name); + + dev = rtems_filesystem_make_dev_t (rtems_libi2c_major, minor); + + mode = 0111 | S_IFCHR; + if (drvtbl->ops->read_entry) + mode |= 0444; + if (drvtbl->ops->write_entry) + mode |= 0222; + + /* note that 'umask' is applied to 'mode' */ + if (mknod (str, mode, dev)) { + safe_printf( DRVNM + "Creating device node failed: %s; you can try to do it manually...\n", + strerror (errno)); + } + + free (str); + } + + drvs[i].drv = drvtbl; + + if (drvtbl->ops->initialization_entry) + err = + drvs[i].drv->ops->initialization_entry (rtems_libi2c_major, minor, + 0); + else + err = RTEMS_SUCCESSFUL; + + LIBUNLOCK (); + return err ? -err : minor; + } + } + LIBUNLOCK (); + return -RTEMS_TOO_MANY; +} |