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/*
* Copyright 2007-2019, Haiku, Inc. All rights reserved.
* Distributed under the terms of the MIT License.
*/
#include <Drivers.h>
#include <KernelExport.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#define DRIVER_NAME "mem"
#define DEVICE_NAME "misc/mem"
#define DEVMNT "/dev/"
/* also publish /dev/mem */
#define PUBLISH_DEV_MEM
static status_t mem_open(const char*, uint32, void**);
static status_t mem_close(void*);
static status_t mem_free(void*);
static status_t mem_read(void*, off_t, void*, size_t*);
static status_t mem_write(void*, off_t, const void*, size_t*);
static area_id mem_map_target(off_t position, size_t length, uint32 protection,
void **virtualAddress);
static const char* mem_name[] = {
DEVICE_NAME,
#ifdef PUBLISH_DEV_MEM
DRIVER_NAME,
#endif
NULL
};
device_hooks mem_hooks = {
mem_open,
mem_close,
mem_free,
NULL, /*mem_control,*/
mem_read,
mem_write,
};
int32 api_version = B_CUR_DRIVER_API_VERSION;
status_t
init_hardware(void)
{
return B_OK;
}
status_t
init_driver(void)
{
return B_OK;
}
void
uninit_driver(void)
{
}
const char**
publish_devices(void)
{
return mem_name;
}
device_hooks*
find_device(const char* name)
{
return &mem_hooks;
}
status_t
mem_open(const char* name, uint32 flags, void** cookie)
{
// not really needed.
*cookie = NULL;
return B_OK;
}
status_t
mem_close(void* cookie)
{
return B_OK;
}
status_t
mem_free(void* cookie)
{
return B_OK;
}
status_t
mem_read(void* cookie, off_t position, void* buffer, size_t* numBytes)
{
void *virtualAddress;
area_id area;
status_t status = B_OK;
/* check permissions */
if (getuid() != 0 && geteuid() != 0) {
*numBytes = 0;
return EPERM;
}
area = mem_map_target(position, *numBytes, B_READ_AREA, &virtualAddress);
if (area < 0) {
*numBytes = 0;
return area;
}
if (user_memcpy(buffer, virtualAddress, *numBytes) != B_OK)
status = B_BAD_ADDRESS;
delete_area(area);
return status;
}
status_t
mem_write(void* cookie, off_t position, const void* buffer, size_t* numBytes)
{
void *virtualAddress;
area_id area;
status_t status = B_OK;
/* check permissions */
if (getuid() != 0 && geteuid() != 0) {
*numBytes = 0;
return EPERM;
}
area = mem_map_target(position, *numBytes, B_WRITE_AREA, &virtualAddress);
if (area < 0) {
*numBytes = 0;
return area;
}
if (user_memcpy(virtualAddress, buffer, *numBytes) != B_OK)
status = B_BAD_ADDRESS;
delete_area(area);
return status;
}
area_id
mem_map_target(off_t position, size_t length, uint32 protection,
void **virtualAddress)
{
area_id area;
phys_addr_t physicalAddress;
size_t offset;
size_t size;
/* SIZE_MAX actually but 2G should be enough anyway */
if (length > SSIZE_MAX - B_PAGE_SIZE)
return EINVAL;
/* the first page address */
physicalAddress = (phys_addr_t)position & ~((off_t)B_PAGE_SIZE - 1);
/* offset of target into it */
offset = position - (off_t)physicalAddress;
/* size of the whole mapping (page rounded) */
size = (offset + length + B_PAGE_SIZE - 1) & ~((size_t)B_PAGE_SIZE - 1);
area = map_physical_memory("mem_driver_temp", physicalAddress, size,
B_ANY_KERNEL_ADDRESS, protection, virtualAddress);
if (area < 0)
return area;
*virtualAddress = (void*)((addr_t)(*virtualAddress) + offset);
return area;
}
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