diff options
Diffstat (limited to 'arch/ppc/syslib/todc_time.c')
| -rw-r--r-- | arch/ppc/syslib/todc_time.c | 513 |
1 files changed, 513 insertions, 0 deletions
diff --git a/arch/ppc/syslib/todc_time.c b/arch/ppc/syslib/todc_time.c new file mode 100644 index 00000000000..1323c641c19 --- /dev/null +++ b/arch/ppc/syslib/todc_time.c @@ -0,0 +1,513 @@ +/* + * 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; +} |