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linux-stable-rt/arch/ppc/syslib/todc_time.c

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/*
* arch/ppc/syslib/todc_time.c
*
* Time of Day Clock support for the M48T35, M48T37, M48T59, and MC146818
* Real Time Clocks/Timekeepers.
*
* Author: Mark A. Greer
* mgreer@mvista.com
*
* 2001-2004 (c) MontaVista, Software, Inc. This file is licensed under
* the terms of the GNU General Public License version 2. This program
* is licensed "as is" without any warranty of any kind, whether express
* or implied.
*/
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/bcd.h>
#include <linux/mc146818rtc.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/time.h>
#include <asm/todc.h>
/*
* Depending on the hardware on your board and your board design, the
* RTC/NVRAM may be accessed either directly (like normal memory) or via
* address/data registers. If your board uses the direct method, set
* 'nvram_data' to the base address of your nvram and leave 'nvram_as0' and
* 'nvram_as1' NULL. If your board uses address/data regs to access nvram,
* set 'nvram_as0' to the address of the lower byte, set 'nvram_as1' to the
* address of the upper byte (leave NULL if using mc146818), and set
* 'nvram_data' to the address of the 8-bit data register.
*
* In order to break the assumption that the RTC and NVRAM are accessed by
* the same mechanism, you need to explicitly set 'ppc_md.rtc_read_val' and
* 'ppc_md.rtc_write_val', otherwise the values of 'ppc_md.rtc_read_val'
* and 'ppc_md.rtc_write_val' will be used.
*
* Note: Even though the documentation for the various RTC chips say that it
* take up to a second before it starts updating once the 'R' bit is
* cleared, they always seem to update even though we bang on it many
* times a second. This is true, except for the Dallas Semi 1746/1747
* (possibly others). Those chips seem to have a real problem whenever
* we set the 'R' bit before reading them, they basically stop counting.
* --MAG
*/
/*
* 'todc_info' should be initialized in your *_setup.c file to
* point to a fully initialized 'todc_info_t' structure.
* This structure holds all the register offsets for your particular
* TODC/RTC chip.
* TODC_ALLOC()/TODC_INIT() will allocate and initialize this table for you.
*/
#ifdef RTC_FREQ_SELECT
#undef RTC_FREQ_SELECT
#define RTC_FREQ_SELECT control_b /* Register A */
#endif
#ifdef RTC_CONTROL
#undef RTC_CONTROL
#define RTC_CONTROL control_a /* Register B */
#endif
#ifdef RTC_INTR_FLAGS
#undef RTC_INTR_FLAGS
#define RTC_INTR_FLAGS watchdog /* Register C */
#endif
#ifdef RTC_VALID
#undef RTC_VALID
#define RTC_VALID interrupts /* Register D */
#endif
/* Access routines when RTC accessed directly (like normal memory) */
u_char
todc_direct_read_val(int addr)
{
return readb((void __iomem *)(todc_info->nvram_data + addr));
}
void
todc_direct_write_val(int addr, unsigned char val)
{
writeb(val, (void __iomem *)(todc_info->nvram_data + addr));
return;
}
/* Access routines for accessing m48txx type chips via addr/data regs */
u_char
todc_m48txx_read_val(int addr)
{
outb(addr, todc_info->nvram_as0);
outb(addr>>todc_info->as0_bits, todc_info->nvram_as1);
return inb(todc_info->nvram_data);
}
void
todc_m48txx_write_val(int addr, unsigned char val)
{
outb(addr, todc_info->nvram_as0);
outb(addr>>todc_info->as0_bits, todc_info->nvram_as1);
outb(val, todc_info->nvram_data);
return;
}
/* Access routines for accessing mc146818 type chips via addr/data regs */
u_char
todc_mc146818_read_val(int addr)
{
outb_p(addr, todc_info->nvram_as0);
return inb_p(todc_info->nvram_data);
}
void
todc_mc146818_write_val(int addr, unsigned char val)
{
outb_p(addr, todc_info->nvram_as0);
outb_p(val, todc_info->nvram_data);
}
/*
* Routines to make RTC chips with NVRAM buried behind an addr/data pair
* have the NVRAM and clock regs appear at the same level.
* The NVRAM will appear to start at addr 0 and the clock regs will appear
* to start immediately after the NVRAM (actually, start at offset
* todc_info->nvram_size).
*/
static inline u_char
todc_read_val(int addr)
{
u_char val;
if (todc_info->sw_flags & TODC_FLAG_2_LEVEL_NVRAM) {
if (addr < todc_info->nvram_size) { /* NVRAM */
ppc_md.rtc_write_val(todc_info->nvram_addr_reg, addr);
val = ppc_md.rtc_read_val(todc_info->nvram_data_reg);
}
else { /* Clock Reg */
addr -= todc_info->nvram_size;
val = ppc_md.rtc_read_val(addr);
}
}
else {
val = ppc_md.rtc_read_val(addr);
}
return val;
}
static inline void
todc_write_val(int addr, u_char val)
{
if (todc_info->sw_flags & TODC_FLAG_2_LEVEL_NVRAM) {
if (addr < todc_info->nvram_size) { /* NVRAM */
ppc_md.rtc_write_val(todc_info->nvram_addr_reg, addr);
ppc_md.rtc_write_val(todc_info->nvram_data_reg, val);
}
else { /* Clock Reg */
addr -= todc_info->nvram_size;
ppc_md.rtc_write_val(addr, val);
}
}
else {
ppc_md.rtc_write_val(addr, val);
}
}
/*
* TODC routines
*
* There is some ugly stuff in that there are assumptions for the mc146818.
*
* Assumptions:
* - todc_info->control_a has the offset as mc146818 Register B reg
* - todc_info->control_b has the offset as mc146818 Register A reg
* - m48txx control reg's write enable or 'W' bit is same as
* mc146818 Register B 'SET' bit (i.e., 0x80)
*
* These assumptions were made to make the code simpler.
*/
long __init
todc_time_init(void)
{
u_char cntl_b;
if (!ppc_md.rtc_read_val)
ppc_md.rtc_read_val = ppc_md.nvram_read_val;
if (!ppc_md.rtc_write_val)
ppc_md.rtc_write_val = ppc_md.nvram_write_val;
cntl_b = todc_read_val(todc_info->control_b);
if (todc_info->rtc_type == TODC_TYPE_MC146818) {
if ((cntl_b & 0x70) != 0x20) {
printk(KERN_INFO "TODC %s %s\n",
"real-time-clock was stopped.",
"Now starting...");
cntl_b &= ~0x70;
cntl_b |= 0x20;
}
todc_write_val(todc_info->control_b, cntl_b);
} else if (todc_info->rtc_type == TODC_TYPE_DS17285) {
u_char mode;
mode = todc_read_val(TODC_TYPE_DS17285_CNTL_A);
/* Make sure countdown clear is not set */
mode &= ~0x40;
/* Enable oscillator, extended register set */
mode |= 0x30;
todc_write_val(TODC_TYPE_DS17285_CNTL_A, mode);
} else if (todc_info->rtc_type == TODC_TYPE_DS1501) {
u_char month;
todc_info->enable_read = TODC_DS1501_CNTL_B_TE;
todc_info->enable_write = TODC_DS1501_CNTL_B_TE;
month = todc_read_val(todc_info->month);
if ((month & 0x80) == 0x80) {
printk(KERN_INFO "TODC %s %s\n",
"real-time-clock was stopped.",
"Now starting...");
month &= ~0x80;
todc_write_val(todc_info->month, month);
}
cntl_b &= ~TODC_DS1501_CNTL_B_TE;
todc_write_val(todc_info->control_b, cntl_b);
} else { /* must be a m48txx type */
u_char cntl_a;
todc_info->enable_read = TODC_MK48TXX_CNTL_A_R;
todc_info->enable_write = TODC_MK48TXX_CNTL_A_W;
cntl_a = todc_read_val(todc_info->control_a);
/* Check & clear STOP bit in control B register */
if (cntl_b & TODC_MK48TXX_DAY_CB) {
printk(KERN_INFO "TODC %s %s\n",
"real-time-clock was stopped.",
"Now starting...");
cntl_a |= todc_info->enable_write;
cntl_b &= ~TODC_MK48TXX_DAY_CB;/* Start Oscil */
todc_write_val(todc_info->control_a, cntl_a);
todc_write_val(todc_info->control_b, cntl_b);
}
/* Make sure READ & WRITE bits are cleared. */
cntl_a &= ~(todc_info->enable_write |
todc_info->enable_read);
todc_write_val(todc_info->control_a, cntl_a);
}
return 0;
}
/*
* There is some ugly stuff in that there are assumptions that for a mc146818,
* the todc_info->control_a has the offset of the mc146818 Register B reg and
* that the register'ss 'SET' bit is the same as the m48txx's write enable
* bit in the control register of the m48txx (i.e., 0x80).
*
* It was done to make the code look simpler.
*/
ulong
todc_get_rtc_time(void)
{
uint year = 0, mon = 0, day = 0, hour = 0, min = 0, sec = 0;
uint limit, i;
u_char save_control, uip = 0;
spin_lock(&rtc_lock);
save_control = todc_read_val(todc_info->control_a);
if (todc_info->rtc_type != TODC_TYPE_MC146818) {
limit = 1;
switch (todc_info->rtc_type) {
case TODC_TYPE_DS1553:
case TODC_TYPE_DS1557:
case TODC_TYPE_DS1743:
case TODC_TYPE_DS1746: /* XXXX BAD HACK -> FIX */
case TODC_TYPE_DS1747:
case TODC_TYPE_DS17285:
break;
default:
todc_write_val(todc_info->control_a,
(save_control | todc_info->enable_read));
}
}
else {
limit = 100000000;
}
for (i=0; i<limit; i++) {
if (todc_info->rtc_type == TODC_TYPE_MC146818) {
uip = todc_read_val(todc_info->RTC_FREQ_SELECT);
}
sec = todc_read_val(todc_info->seconds) & 0x7f;
min = todc_read_val(todc_info->minutes) & 0x7f;
hour = todc_read_val(todc_info->hours) & 0x3f;
day = todc_read_val(todc_info->day_of_month) & 0x3f;
mon = todc_read_val(todc_info->month) & 0x1f;
year = todc_read_val(todc_info->year) & 0xff;
if (todc_info->rtc_type == TODC_TYPE_MC146818) {
uip |= todc_read_val(todc_info->RTC_FREQ_SELECT);
if ((uip & RTC_UIP) == 0) break;
}
}
if (todc_info->rtc_type != TODC_TYPE_MC146818) {
switch (todc_info->rtc_type) {
case TODC_TYPE_DS1553:
case TODC_TYPE_DS1557:
case TODC_TYPE_DS1743:
case TODC_TYPE_DS1746: /* XXXX BAD HACK -> FIX */
case TODC_TYPE_DS1747:
case TODC_TYPE_DS17285:
break;
default:
save_control &= ~(todc_info->enable_read);
todc_write_val(todc_info->control_a,
save_control);
}
}
spin_unlock(&rtc_lock);
if ((todc_info->rtc_type != TODC_TYPE_MC146818) ||
((save_control & RTC_DM_BINARY) == 0) ||
RTC_ALWAYS_BCD) {
BCD_TO_BIN(sec);
BCD_TO_BIN(min);
BCD_TO_BIN(hour);
BCD_TO_BIN(day);
BCD_TO_BIN(mon);
BCD_TO_BIN(year);
}
year = year + 1900;
if (year < 1970) {
year += 100;
}
return mktime(year, mon, day, hour, min, sec);
}
int
todc_set_rtc_time(unsigned long nowtime)
{
struct rtc_time tm;
u_char save_control, save_freq_select = 0;
spin_lock(&rtc_lock);
to_tm(nowtime, &tm);
save_control = todc_read_val(todc_info->control_a);
/* Assuming MK48T59_RTC_CA_WRITE & RTC_SET are equal */
todc_write_val(todc_info->control_a,
(save_control | todc_info->enable_write));
save_control &= ~(todc_info->enable_write); /* in case it was set */
if (todc_info->rtc_type == TODC_TYPE_MC146818) {
save_freq_select = todc_read_val(todc_info->RTC_FREQ_SELECT);
todc_write_val(todc_info->RTC_FREQ_SELECT,
save_freq_select | RTC_DIV_RESET2);
}
tm.tm_year = (tm.tm_year - 1900) % 100;
if ((todc_info->rtc_type != TODC_TYPE_MC146818) ||
((save_control & RTC_DM_BINARY) == 0) ||
RTC_ALWAYS_BCD) {
BIN_TO_BCD(tm.tm_sec);
BIN_TO_BCD(tm.tm_min);
BIN_TO_BCD(tm.tm_hour);
BIN_TO_BCD(tm.tm_mon);
BIN_TO_BCD(tm.tm_mday);
BIN_TO_BCD(tm.tm_year);
}
todc_write_val(todc_info->seconds, tm.tm_sec);
todc_write_val(todc_info->minutes, tm.tm_min);
todc_write_val(todc_info->hours, tm.tm_hour);
todc_write_val(todc_info->month, tm.tm_mon);
todc_write_val(todc_info->day_of_month, tm.tm_mday);
todc_write_val(todc_info->year, tm.tm_year);
todc_write_val(todc_info->control_a, save_control);
if (todc_info->rtc_type == TODC_TYPE_MC146818) {
todc_write_val(todc_info->RTC_FREQ_SELECT, save_freq_select);
}
spin_unlock(&rtc_lock);
return 0;
}
/*
* Manipulates read bit to reliably read seconds at a high rate.
*/
static unsigned char __init todc_read_timereg(int addr)
{
unsigned char save_control = 0, val;
switch (todc_info->rtc_type) {
case TODC_TYPE_DS1553:
case TODC_TYPE_DS1557:
case TODC_TYPE_DS1746: /* XXXX BAD HACK -> FIX */
case TODC_TYPE_DS1747:
case TODC_TYPE_DS17285:
case TODC_TYPE_MC146818:
break;
default:
save_control = todc_read_val(todc_info->control_a);
todc_write_val(todc_info->control_a,
(save_control | todc_info->enable_read));
}
val = todc_read_val(addr);
switch (todc_info->rtc_type) {
case TODC_TYPE_DS1553:
case TODC_TYPE_DS1557:
case TODC_TYPE_DS1746: /* XXXX BAD HACK -> FIX */
case TODC_TYPE_DS1747:
case TODC_TYPE_DS17285:
case TODC_TYPE_MC146818:
break;
default:
save_control &= ~(todc_info->enable_read);
todc_write_val(todc_info->control_a, save_control);
}
return val;
}
/*
* This was taken from prep_setup.c
* Use the NVRAM RTC to time a second to calibrate the decrementer.
*/
void __init
todc_calibrate_decr(void)
{
ulong freq;
ulong tbl, tbu;
long i, loop_count;
u_char sec;
todc_time_init();
/*
* Actually this is bad for precision, we should have a loop in
* which we only read the seconds counter. todc_read_val writes
* the address bytes on every call and this takes a lot of time.
* Perhaps an nvram_wait_change method returning a time
* stamp with a loop count as parameter would be the solution.
*/
/*
* Need to make sure the tbl doesn't roll over so if tbu increments
* during this test, we need to do it again.
*/
loop_count = 0;
sec = todc_read_timereg(todc_info->seconds) & 0x7f;
do {
tbu = get_tbu();
for (i = 0 ; i < 10000000 ; i++) {/* may take up to 1 second */
tbl = get_tbl();
if ((todc_read_timereg(todc_info->seconds) & 0x7f) != sec) {
break;
}
}
sec = todc_read_timereg(todc_info->seconds) & 0x7f;
for (i = 0 ; i < 10000000 ; i++) { /* Should take 1 second */
freq = get_tbl();
if ((todc_read_timereg(todc_info->seconds) & 0x7f) != sec) {
break;
}
}
freq -= tbl;
} while ((get_tbu() != tbu) && (++loop_count < 2));
printk("time_init: decrementer frequency = %lu.%.6lu MHz\n",
freq/1000000, freq%1000000);
tb_ticks_per_jiffy = freq / HZ;
tb_to_us = mulhwu_scale_factor(freq, 1000000);
return;
}
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