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linux/arch/mips/powertv/powertv_setup.c

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/*
* Carsten Langgaard, carstenl@mips.com
* Copyright (C) 2000 MIPS Technologies, Inc. All rights reserved.
* Portions copyright (C) 2009 Cisco Systems, Inc.
*
* This program is free software; you can distribute it and/or modify it
* under the terms of the GNU General Public License (Version 2) as
* published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
*/
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/pci.h>
#include <linux/screen_info.h>
#include <linux/notifier.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/ctype.h>
#include <linux/cpu.h>
#include <linux/time.h>
#include <asm/bootinfo.h>
#include <asm/irq.h>
#include <asm/mips-boards/generic.h>
#include <asm/mips-boards/prom.h>
#include <asm/dma.h>
#include <asm/asm.h>
#include <asm/traps.h>
#include <asm/asm-offsets.h>
#include "reset.h"
#define VAL(n) STR(n)
/*
* Macros for loading addresses and storing registers:
* LONG_L_ Stringified version of LONG_L for use in asm() statement
* LONG_S_ Stringified version of LONG_S for use in asm() statement
* PTR_LA_ Stringified version of PTR_LA for use in asm() statement
* REG_SIZE Number of 8-bit bytes in a full width register
*/
#define LONG_L_ VAL(LONG_L) " "
#define LONG_S_ VAL(LONG_S) " "
#define PTR_LA_ VAL(PTR_LA) " "
#ifdef CONFIG_64BIT
#warning TODO: 64-bit code needs to be verified
#define REG_SIZE "8" /* In bytes */
#endif
#ifdef CONFIG_32BIT
#define REG_SIZE "4" /* In bytes */
#endif
static void register_panic_notifier(void);
static int panic_handler(struct notifier_block *notifier_block,
unsigned long event, void *cause_string);
const char *get_system_type(void)
{
return "PowerTV";
}
void __init plat_mem_setup(void)
{
panic_on_oops = 1;
register_panic_notifier();
#if 0
mips_pcibios_init();
#endif
mips_reboot_setup();
}
/*
* Install a panic notifier for platform-specific diagnostics
*/
static void register_panic_notifier()
{
static struct notifier_block panic_notifier = {
.notifier_call = panic_handler,
.next = NULL,
.priority = INT_MAX
};
atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier);
}
static int panic_handler(struct notifier_block *notifier_block,
unsigned long event, void *cause_string)
{
struct pt_regs my_regs;
/* Save all of the registers */
{
unsigned long at, v0, v1; /* Must be on the stack */
/* Start by saving $at and v0 on the stack. We use $at
* ourselves, but it looks like the compiler may use v0 or v1
* to load the address of the pt_regs structure. We'll come
* back later to store the registers in the pt_regs
* structure. */
__asm__ __volatile__ (
".set noat\n"
LONG_S_ "$at, %[at]\n"
LONG_S_ "$2, %[v0]\n"
LONG_S_ "$3, %[v1]\n"
:
[at] "=m" (at),
[v0] "=m" (v0),
[v1] "=m" (v1)
:
: "at"
);
__asm__ __volatile__ (
".set noat\n"
"move $at, %[pt_regs]\n"
/* Argument registers */
LONG_S_ "$4, " VAL(PT_R4) "($at)\n"
LONG_S_ "$5, " VAL(PT_R5) "($at)\n"
LONG_S_ "$6, " VAL(PT_R6) "($at)\n"
LONG_S_ "$7, " VAL(PT_R7) "($at)\n"
/* Temporary regs */
LONG_S_ "$8, " VAL(PT_R8) "($at)\n"
LONG_S_ "$9, " VAL(PT_R9) "($at)\n"
LONG_S_ "$10, " VAL(PT_R10) "($at)\n"
LONG_S_ "$11, " VAL(PT_R11) "($at)\n"
LONG_S_ "$12, " VAL(PT_R12) "($at)\n"
LONG_S_ "$13, " VAL(PT_R13) "($at)\n"
LONG_S_ "$14, " VAL(PT_R14) "($at)\n"
LONG_S_ "$15, " VAL(PT_R15) "($at)\n"
/* "Saved" registers */
LONG_S_ "$16, " VAL(PT_R16) "($at)\n"
LONG_S_ "$17, " VAL(PT_R17) "($at)\n"
LONG_S_ "$18, " VAL(PT_R18) "($at)\n"
LONG_S_ "$19, " VAL(PT_R19) "($at)\n"
LONG_S_ "$20, " VAL(PT_R20) "($at)\n"
LONG_S_ "$21, " VAL(PT_R21) "($at)\n"
LONG_S_ "$22, " VAL(PT_R22) "($at)\n"
LONG_S_ "$23, " VAL(PT_R23) "($at)\n"
/* Add'l temp regs */
LONG_S_ "$24, " VAL(PT_R24) "($at)\n"
LONG_S_ "$25, " VAL(PT_R25) "($at)\n"
/* Kernel temp regs */
LONG_S_ "$26, " VAL(PT_R26) "($at)\n"
LONG_S_ "$27, " VAL(PT_R27) "($at)\n"
/* Global pointer, stack pointer, frame pointer and
* return address */
LONG_S_ "$gp, " VAL(PT_R28) "($at)\n"
LONG_S_ "$sp, " VAL(PT_R29) "($at)\n"
LONG_S_ "$fp, " VAL(PT_R30) "($at)\n"
LONG_S_ "$ra, " VAL(PT_R31) "($at)\n"
/* Now we can get the $at and v0 registers back and
* store them */
LONG_L_ "$8, %[at]\n"
LONG_S_ "$8, " VAL(PT_R1) "($at)\n"
LONG_L_ "$8, %[v0]\n"
LONG_S_ "$8, " VAL(PT_R2) "($at)\n"
LONG_L_ "$8, %[v1]\n"
LONG_S_ "$8, " VAL(PT_R3) "($at)\n"
:
:
[at] "m" (at),
[v0] "m" (v0),
[v1] "m" (v1),
[pt_regs] "r" (&my_regs)
: "at", "t0"
);
/* Set the current EPC value to be the current location in this
* function */
__asm__ __volatile__ (
".set noat\n"
"1:\n"
PTR_LA_ "$at, 1b\n"
LONG_S_ "$at, %[cp0_epc]\n"
:
[cp0_epc] "=m" (my_regs.cp0_epc)
:
: "at"
);
my_regs.cp0_cause = read_c0_cause();
my_regs.cp0_status = read_c0_status();
}
pr_crit("I'm feeling a bit sleepy. hmmmmm... perhaps a nap would... "
"zzzz... \n");
return NOTIFY_DONE;
}
/* Information about the RF MAC address, if one was supplied on the
* command line. */
static bool have_rfmac;
static u8 rfmac[ETH_ALEN];
static int rfmac_param(char *p)
{
u8 *q;
bool is_high_nibble;
int c;
/* Skip a leading "0x", if present */
if (*p == '0' && *(p+1) == 'x')
p += 2;
q = rfmac;
is_high_nibble = true;
for (c = (unsigned char) *p++;
isxdigit(c) && q - rfmac < ETH_ALEN;
c = (unsigned char) *p++) {
int nibble;
nibble = (isdigit(c) ? (c - '0') :
(isupper(c) ? c - 'A' + 10 : c - 'a' + 10));
if (is_high_nibble)
*q = nibble << 4;
else
*q++ |= nibble;
is_high_nibble = !is_high_nibble;
}
/* If we parsed all the way to the end of the parameter value and
* parsed all ETH_ALEN bytes, we have a usable RF MAC address */
have_rfmac = (c == '\0' && q - rfmac == ETH_ALEN);
return 0;
}
early_param("rfmac", rfmac_param);
/*
* Generate an Ethernet MAC address that has a good chance of being unique.
* @addr: Pointer to six-byte array containing the Ethernet address
* Generates an Ethernet MAC address that is highly likely to be unique for
* this particular system on a network with other systems of the same type.
*
* The problem we are solving is that, when random_ether_addr() is used to
* generate MAC addresses at startup, there isn't much entropy for the random
* number generator to use and the addresses it produces are fairly likely to
* be the same as those of other identical systems on the same local network.
* This is true even for relatively small numbers of systems (for the reason
* why, see the Wikipedia entry for "Birthday problem" at:
* http://en.wikipedia.org/wiki/Birthday_problem
*
* The good news is that we already have a MAC address known to be unique, the
* RF MAC address. The bad news is that this address is already in use on the
* RF interface. Worse, the obvious trick, taking the RF MAC address and
* turning on the locally managed bit, has already been used for other devices.
* Still, this does give us something to work with.
*
* The approach we take is:
* 1. If we can't get the RF MAC Address, just call random_ether_addr.
* 2. Use the 24-bit NIC-specific bits of the RF MAC address as the last 24
* bits of the new address. This is very likely to be unique, except for
* the current box.
* 3. To avoid using addresses already on the current box, we set the top
* six bits of the address with a value different from any currently
* registered Scientific Atlanta organizationally unique identifyer
* (OUI). This avoids duplication with any addresses on the system that
* were generated from valid Scientific Atlanta-registered address by
* simply flipping the locally managed bit.
* 4. We aren't generating a multicast address, so we leave the multicast
* bit off. Since we aren't using a registered address, we have to set
* the locally managed bit.
* 5. We then randomly generate the remaining 16-bits. This does two
* things:
* a. It allows us to call this function for more than one device
* in this system
* b. It ensures that things will probably still work even if
* some device on the device network has a locally managed
* address that matches the top six bits from step 2.
*/
void platform_random_ether_addr(u8 addr[ETH_ALEN])
{
const int num_random_bytes = 2;
const unsigned char non_sciatl_oui_bits = 0xc0u;
const unsigned char mac_addr_locally_managed = (1 << 1);
if (!have_rfmac) {
pr_warning("rfmac not available on command line; "
"generating random MAC address\n");
random_ether_addr(addr);
}
else {
int i;
/* Set the first byte to something that won't match a Scientific
* Atlanta OUI, is locally managed, and isn't a multicast
* address */
addr[0] = non_sciatl_oui_bits | mac_addr_locally_managed;
/* Get some bytes of random address information */
get_random_bytes(&addr[1], num_random_bytes);
/* Copy over the NIC-specific bits of the RF MAC address */
for (i = 1 + num_random_bytes; i < ETH_ALEN; i++)
addr[i] = rfmac[i];
}
}
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