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tamper.c
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tamper.c
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/*
* Copyright (C) 2016 by Digi International Inc.
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version2 as published by
* the Free Software Foundation.
*/
#include <common.h>
#include <libfdt.h>
#include "../common/mca_registers.h"
#include "../common/tamper.h"
DECLARE_GLOBAL_DATA_PTR;
extern int mca_bulk_read(int reg, unsigned char *values, int len);
extern int mca_write_reg(int reg, unsigned char value);
__weak void mca_tamper_take_actions(int iface)
{
/* Override this function with a custom implementation... */
printf("\nTamper%d Event!!\n", iface);
printf("No specific action was implemented\n\n");
}
#ifdef MCA_TAMPER_USE_DT
static int mca_tamper_iface_enabled_in_dt(int iface)
{
const int *tamper_iface_prop;
int iface_enabled = 0, tamper_iface;
int node;
/* get the right fdt_blob from the global working_fdt */
gd->fdt_blob = working_fdt;
/* Get the node from FDT for mca tamper */
node = fdt_node_offset_by_compatible(gd->fdt_blob, -1,
"digi,mca-cc6ul-tamper");
if (node < 0) {
#ifdef MCA_TAMPER_DEBUG
printf("No mca tamper device node %d, force to disable\n", node);
#endif
return 0;
}
for (; node > 0; node = fdt_next_property_offset(gd->fdt_blob, node)) {
tamper_iface_prop = fdt_getprop(gd->fdt_blob, node,
"digi,tamper-if-list", NULL);
if (!tamper_iface_prop)
continue;
tamper_iface = fdt32_to_cpu(*tamper_iface_prop);
if (tamper_iface == iface) {
iface_enabled = 1;
break;
}
}
#ifdef MCA_TAMPER_DEBUG
printf("Tamper%d %s\n", iface, iface_enabled ? "enabled" : "disabled");
#endif
return iface_enabled;
}
#endif
static unsigned int get_tamper_base_reg(unsigned int iface)
{
switch (iface) {
case 0:
return MCA_CC6UL_TAMPER0_CFG0;
case 1:
return MCA_CC6UL_TAMPER1_CFG0;
case 2:
return MCA_CC6UL_TAMPER2_CFG0;
case 3:
return MCA_CC6UL_TAMPER3_CFG0;
default:
printf("MCA: tamper interface %d not supported\n", iface);
break;
}
return ~0;
}
static void mca_tamper_ack_event(int iface)
{
int ret;
unsigned int regaddr = get_tamper_base_reg(iface);
if (regaddr == ~0)
return;
/* Ack the tamper event */
ret = mca_write_reg(regaddr + MCA_CC6UL_TAMPER_EV_OFFSET,
MCA_CC6UL_TAMPER_ACKED);
if (ret)
printf("MCA: unable to write Tamper%d event register\n", iface);
mdelay(100);
}
static int mca_tamper_check_event(int iface)
{
unsigned char data[MCA_CC6UL_TAMPER_REG_LEN];
int ret;
unsigned int regaddr = get_tamper_base_reg(iface);
if (regaddr == ~0)
return 0;
ret = mca_bulk_read(regaddr, data, MCA_CC6UL_TAMPER_REG_LEN);
if (ret) {
printf("MCA: unable to read Tamper%d registers\n", iface);
/* Return a tamper condition as the MCA could have been tampered */
return 1;
}
/* Skip if tamper pin is not enabled */
if (!(data[MCA_CC6UL_TAMPER_CFG0_OFFSET] & MCA_CC6UL_TAMPER_DET_EN))
return 0;
/* Check if there is an event signaled that has not been acked */
if (data[MCA_CC6UL_TAMPER_EV_OFFSET] & MCA_CC6UL_TAMPER_SIGNALED &&
!(data[MCA_CC6UL_TAMPER_EV_OFFSET] & MCA_CC6UL_TAMPER_ACKED))
return 1;
return 0;
}
void mca_tamper_check_events(void)
{
int i;
for (i = 0; i < MCA_MAX_TAMPER_PINS; i++) {
#ifdef MCA_TAMPER_USE_DT
/* Check if interface is enabled in DT */
if (!mca_tamper_iface_enabled_in_dt(i))
continue;
#endif
/* Check if there is a tamper event signaled and not acked */
if (!mca_tamper_check_event(i))
continue;
/* Take the neccesary actions */
mca_tamper_take_actions(i);
/* And finally ack the event */
mca_tamper_ack_event(i);
}
}