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/* Copyright 2016 IBM Corp.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _LARGEFILE64_SOURCE
#define _LARGEFILE64_SOURCE
#endif
#define _GNU_SOURCE
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <assert.h>
#include <errno.h>
#include <err.h>
#include <inttypes.h>
#include "bitutils.h"
#include "operations.h"
#include "hwunit.h"
#define XSCOM_BASE_PATH "/sys/kernel/debug/powerpc/scom"
static uint64_t xscom_mangle_addr(uint64_t addr)
{
uint64_t tmp;
/*
* Shift the top 4 bits (indirect mode) down by 4 bits so we
* don't lose going through the debugfs interfaces.
*/
tmp = (addr & 0xf000000000000000) >> 4;
addr &= 0x00ffffffffffffff;
addr |= tmp;
/* Shift up by 3 for debugfs */
return addr << 3;
}
static int xscom_read(struct pib *pib, uint64_t addr, uint64_t *val)
{
int rc;
int fd = pib->fd;
addr = xscom_mangle_addr(addr);
lseek64(fd, addr, SEEK_SET);
rc = read(fd, val, 8);
if (rc != 8)
return -1;
return 0;
}
static int xscom_write(struct pib *pib, uint64_t addr, uint64_t val)
{
int rc;
int fd = pib->fd;
addr = xscom_mangle_addr(addr);
lseek64(fd, addr, SEEK_SET);
rc = write(fd, &val, 8);
if (rc != 8)
return -1;
return 0;
}
static int host_pib_probe(struct pdbg_target *target)
{
struct pib *pib = target_to_pib(target);
int fd;
char *access_fn;
uint32_t chip;
if (pdbg_target_u32_property(target, "reg", &chip))
return -1;
/* This check should probably be done earlier */
if (access(XSCOM_BASE_PATH, F_OK) == -1)
{
PR_ERROR("Can not access %s. ", XSCOM_BASE_PATH);
PR_ERROR("Is CONFIG_SCOM_DEBUGFS set? ");
PR_ERROR("You may need to re-run the command as root.\n");
}
if (asprintf(&access_fn, "%s/%08x/access", XSCOM_BASE_PATH, chip) < 0)
return -1;
fd = open(access_fn, O_RDWR);
free(access_fn);
if (fd < 0)
return -1;
pib->fd = fd;
return 0;
}
static struct pib host_pib = {
.target = {
.name = "Host based debugfs SCOM",
.compatible = "ibm,host-pib",
.class = "pib",
.probe = host_pib_probe,
},
.read = xscom_read,
.write = xscom_write,
.fd = -1,
};
DECLARE_HW_UNIT(host_pib);
__attribute__((constructor))
static void register_host(void)
{
pdbg_hwunit_register(PDBG_DEFAULT_BACKEND, &host_pib_hw_unit);
}
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