File: [local] / prex / sys / kern / device.c (download)
Revision 1.1.1.1 (vendor branch), Tue Aug 19 12:46:56 2008 UTC (15 years, 10 months ago) by nbrk
Branch: MAIN, KOHSUKE
CVS Tags: PREX_0_8_BASE, HEAD Changes since 1.1: +0 -0 lines
Initial import of Prex, Portable Real-time Embedded POSIX microkernel system.
I have totally new directions in my development (more focused on real hardware, not virtual one).
Old hacks are available in prex-old module. They will be carefully re-designed and merged soon.
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/*-
* Copyright (c) 2005-2007, Kohsuke Ohtani
* All rights reserved.
*
* 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 of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
/*
* device.c - device I/O support routines
*/
/*
* The device_* system calls are interfaces for user mode
* applications to access the specific device object which is
* handled by the related device driver. A device driver is an
* execution module different from a kernel on Prex. The routines
* in this file have the following role to handle the device I/O.
*
* - Manage the name space for device objects.
* - Forward user I/O requests to the drivers after checking
* parameters.
*
* The driver module(s) and kernel are dynamically linked
* at system boot.
*/
#include <kernel.h>
#include <irq.h>
#include <page.h>
#include <kmem.h>
#include <task.h>
#include <timer.h>
#include <sched.h>
#include <exception.h>
#include <vm.h>
#include <device.h>
#include <system.h>
/* forward declarations */
static device_t device_create(struct devio *, const char *, int);
static int device_destroy(device_t);
static int device_broadcast(int, int);
static void machine_bootinfo(struct boot_info **);
static void _machine_reset(void);
static void _machine_idle(void);
static int _task_capable(cap_t);
static void *_phys_to_virt(void *);
static void *_virt_to_phys(void *);
#ifdef DEBUG
#define _debug_attach debug_attach
#define _debug_dump debug_dump
#define _printf printf
#define _panic panic
#else
#define _debug_attach nosys
#define _debug_dump nosys
#define _printf nosys
#define _panic machine_reset
static void nosys(void);
#endif
typedef void (*dkifn_t)(void);
#define DKIENT(func) (dkifn_t)(func)
/*
* Driver-Kernel Interface (DKI)
*/
static const dkifn_t driver_service[] = {
/* 0 */ DKIENT(device_create),
/* 1 */ DKIENT(device_destroy),
/* 2 */ DKIENT(device_broadcast),
/* 3 */ DKIENT(umem_copyin),
/* 4 */ DKIENT(umem_copyout),
/* 5 */ DKIENT(umem_strnlen),
/* 6 */ DKIENT(kmem_alloc),
/* 7 */ DKIENT(kmem_free),
/* 8 */ DKIENT(kmem_map),
/* 9 */ DKIENT(page_alloc),
/* 10 */ DKIENT(page_free),
/* 11 */ DKIENT(page_reserve),
/* 12 */ DKIENT(irq_attach),
/* 13 */ DKIENT(irq_detach),
/* 14 */ DKIENT(irq_lock),
/* 15 */ DKIENT(irq_unlock),
/* 16 */ DKIENT(timer_callout),
/* 17 */ DKIENT(timer_stop),
/* 18 */ DKIENT(timer_delay),
/* 19 */ DKIENT(timer_count),
/* 20 */ DKIENT(timer_hook),
/* 21 */ DKIENT(sched_lock),
/* 22 */ DKIENT(sched_unlock),
/* 23 */ DKIENT(sched_tsleep),
/* 24 */ DKIENT(sched_wakeup),
/* 25 */ DKIENT(sched_dpc),
/* 26 */ DKIENT(_task_capable),
/* 27 */ DKIENT(exception_post),
/* 28 */ DKIENT(machine_bootinfo),
/* 29 */ DKIENT(_machine_reset),
/* 30 */ DKIENT(_machine_idle),
/* 31 */ DKIENT(_phys_to_virt),
/* 32 */ DKIENT(_virt_to_phys),
/* 33 */ DKIENT(_debug_attach),
/* 34 */ DKIENT(_debug_dump),
/* 35 */ DKIENT(_printf),
/* 36 */ DKIENT(_panic),
};
static struct list device_list; /* list of the device objects */
/*
* Increment reference count on an active device.
* It returns 0 on success, or -1 if the device is invalid.
*/
static int
device_hold(device_t dev)
{
int err = -1;
sched_lock();
if (device_valid(dev)) {
dev->refcnt++;
err = 0;
}
sched_unlock();
return err;
}
/*
* Decrement the reference count on a device. If the
* reference count becomes zero, we can release the
* resource for the target device. Assumes the device
* is already validated by caller.
*/
static void
device_release(device_t dev)
{
sched_lock();
if (--dev->refcnt == 0) {
list_remove(&dev->link);
kmem_free(dev);
}
sched_unlock();
}
/*
* Look up a device object by device name.
* Return device ID on success, or NULL on failure.
* This must be called with scheduler locked.
*/
static device_t
device_lookup(const char *name)
{
list_t head, n;
device_t dev;
if (name == NULL)
return NULL;
head = &device_list;
for (n = list_first(head); n != head; n = list_next(n)) {
dev = list_entry(n, struct device, link);
if (!strncmp(dev->name, name, MAXDEVNAME))
return dev;
}
return NULL;
}
/*
* device_create - create new device object.
*
* A device object is created by the device driver to provide
* I/O services to applications.
* Returns device ID on success, or 0 on failure.
*/
static device_t
device_create(struct devio *io, const char *name, int flags)
{
device_t dev;
size_t len;
ASSERT(irq_level == 0);
len = strnlen(name, MAXDEVNAME);
if (len == 0 || len >= MAXDEVNAME) /* Invalid name? */
return 0;
sched_lock();
if ((dev = device_lookup(name)) != NULL) {
/*
* Error - the device name is already used.
*/
sched_unlock();
return 0;
}
if ((dev = kmem_alloc(sizeof(struct device))) == NULL) {
sched_unlock();
return 0;
}
strlcpy(dev->name, name, len + 1);
dev->devio = io;
dev->flags = flags;
dev->refcnt = 1;
dev->magic = DEVICE_MAGIC;
list_insert(&device_list, &dev->link);
sched_unlock();
return dev;
}
/*
* Destroy a device object. If some other threads still
* refer the target device, the destroy operating will be
* pending until its reference count becomes 0.
*/
static int
device_destroy(device_t dev)
{
int err = 0;
ASSERT(irq_level == 0);
sched_lock();
if (device_valid(dev))
device_release(dev);
else
err = ENODEV;
sched_unlock();
return err;
}
/*
* device_open - open the specified device.
*
* Even if the target driver does not have an open
* routine, this function does not return an error. By
* using this mechanism, an application can check whether
* the specific device exists or not. The open mode
* should be handled by an each device driver if it is
* needed.
*/
int
device_open(const char *name, int mode, device_t *devp)
{
char str[MAXDEVNAME];
device_t dev;
size_t len;
int err = 0;
if (!task_capable(CAP_DEVIO))
return EPERM;
if (umem_strnlen(name, MAXDEVNAME, &len))
return EFAULT;
if (len == 0)
return ENOENT;
if (len >= MAXDEVNAME)
return ENAMETOOLONG;
if (umem_copyin(name, str, len + 1))
return EFAULT;
sched_lock();
if ((dev = device_lookup(str)) == NULL) {
sched_unlock();
return ENXIO;
}
device_hold(dev);
sched_unlock();
if (dev->devio->open != NULL)
err = (*dev->devio->open)(dev, mode);
if (!err)
err = umem_copyout(&dev, devp, sizeof(dev));
device_release(dev);
return err;
}
/*
* device_close - close a device.
*
* Even if the target driver does not have close routine,
* this function does not return any errors.
*/
int
device_close(device_t dev)
{
int err = 0;
if (!task_capable(CAP_DEVIO))
return EPERM;
if (device_hold(dev))
return ENODEV;
if (dev->devio->close != NULL)
err = (*dev->devio->close)(dev);
device_release(dev);
return err;
}
/*
* device_read - read from a device.
*
* Actual read count is set in "nbyte" as return.
* Note: The size of one block is device dependent.
*/
int
device_read(device_t dev, void *buf, size_t *nbyte, int blkno)
{
size_t count;
int err;
if (!task_capable(CAP_DEVIO))
return EPERM;
if (device_hold(dev))
return ENODEV;
if (dev->devio->read == NULL) {
device_release(dev);
return EBADF;
}
if (umem_copyin(nbyte, &count, sizeof(count))) {
device_release(dev);
return EFAULT;
}
err = (*dev->devio->read)(dev, buf, &count, blkno);
if (err == 0)
err = umem_copyout(&count, nbyte, sizeof(count));
device_release(dev);
return err;
}
/*
* device_write - write to a device.
*
* Actual write count is set in "nbyte" as return.
*/
int
device_write(device_t dev, void *buf, size_t *nbyte, int blkno)
{
size_t count;
int err;
if (!task_capable(CAP_DEVIO))
return EPERM;
if (device_hold(dev))
return ENODEV;
if (dev->devio->write == NULL) {
device_release(dev);
return EBADF;
}
if (umem_copyin(nbyte, &count, sizeof(count))) {
device_release(dev);
return EFAULT;
}
err = (*dev->devio->write)(dev, buf, &count, blkno);
if (err == 0)
err = umem_copyout(&count, nbyte, sizeof(count));
device_release(dev);
return err;
}
/*
* device_ioctl - I/O control request.
*
* A command and an argument are completely device dependent.
* The ioctl routine of each driver must validate the user buffer
* pointed by the arg value.
*/
int
device_ioctl(device_t dev, u_long cmd, void *arg)
{
int err = EBADF;
if (!task_capable(CAP_DEVIO))
return EPERM;
if (device_hold(dev))
return ENODEV;
if (dev->devio->ioctl != NULL)
err = (*dev->devio->ioctl)(dev, cmd, arg);
device_release(dev);
return err;
}
/*
* device_broadcast - broadcast an event to all device objects.
*
* If "force" argument is true, a kernel will continue event
* notification even if some driver returns error. In this case,
* this routine returns EIO error if at least one driver returns
* an error.
*
* If force argument is false, a kernel stops the event processing
* when at least one driver returns an error. In this case,
* device_broadcast will return the error code which is returned
* by the driver.
*/
static int
device_broadcast(int event, int force)
{
device_t dev;
list_t head, n;
int err, ret = 0;
sched_lock();
head = &device_list;
for (n = list_first(head); n != head; n = list_next(n)) {
dev = list_entry(n, struct device, link);
if (dev->devio->event != NULL) {
/*
* Call driver's event routine.
*/
err = (*dev->devio->event)(event);
if (err) {
if (force)
ret = EIO;
else {
ret = err;
break;
}
}
}
}
sched_unlock();
return ret;
}
/*
* Return device information (for devfs).
*/
int
device_info(struct info_device *info)
{
u_long index, target = info->cookie;
device_t dev;
struct devio *io;
list_t head, n;
int err = ESRCH;
sched_lock();
index = 0;
head = &device_list;
for (n = list_first(head); n != head; n = list_next(n)) {
dev = list_entry(n, struct device, link);
io = dev->devio;
if (index == target) {
info->id = dev;
info->flags = dev->flags;
strlcpy(info->name, dev->name, MAXDEVNAME);
err = 0;
break;
}
index++;
}
sched_unlock();
return err;
}
#ifndef DEBUG
/*
* nonexistent driver service.
*/
static void
nosys(void)
{
}
#endif
/*
* Check the capability of the current task.
*/
static int
_task_capable(cap_t cap)
{
return task_capable(cap);
}
/*
* Return boot information
*/
static void
machine_bootinfo(struct boot_info **info)
{
ASSERT(info != NULL);
*info = boot_info;
}
static void
_machine_reset(void)
{
machine_reset();
}
static void
_machine_idle(void)
{
machine_idle();
}
/*
* Address translation (physical -> virtual)
*/
static void *
_phys_to_virt(void *phys)
{
return phys_to_virt(phys);
}
/*
* Address translation (virtual -> physical)
*/
static void *
_virt_to_phys(void *virt)
{
return virt_to_phys(virt);
}
/*
* Initialize device driver module.
*/
void
device_init(void)
{
struct module *mod;
void (*drv_entry)(const dkifn_t *);
list_init(&device_list);
mod = &boot_info->driver;
if (mod == NULL)
return;
drv_entry = (void (*)(const dkifn_t *))mod->entry;
if (drv_entry == NULL)
return;
/*
* Call all initialization functions in drivers.
*/
(*drv_entry)(driver_service);
}