[POWERPC] todc: add support for Time-Of-Day-Clock

This is a resubmit with a proper subject and with all comments addressed.
Applies cleanly to powerpc.git 649e85797259162f7fdc696420e7492f20226f2d

Mark
--

The todc code from arch/ppc supports many todc/rtc chips and is needed
in arch/powerpc.  This patch adds the todc code to arch/powerpc.

Signed-off-by: Mark A. Greer <mgreer@mvista.com>
--

 arch/powerpc/Kconfig         |    7
 arch/powerpc/sysdev/Makefile |    1
 arch/powerpc/sysdev/todc.c   |  392 ++++++++++++++++++++++++++++++++++
 include/asm-powerpc/todc.h   |  487 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 887 insertions(+)
--
Signed-off-by: Paul Mackerras <paulus@samba.org>

3 files changed, 400 insertions, 0 deletions

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 0b5e225..e898da2 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -563,6 +563,13 @@ config TAU_AVERAGE
 	  /proc/cpuinfo.
 
 	  If in doubt, say N here.
+
+config PPC_TODC
+	depends on EMBEDDED6xx
+	bool "Generic Time-of-day Clock (TODC) support"
+	---help---
+	  This adds support for many TODC/RTC chips.
+
 endmenu
 
 source arch/powerpc/platforms/embedded6xx/Kconfig
diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index 63e81e7..054bd8b 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -12,4 +12,5 @@ obj-$(CONFIG_U3_DART)		+= dart_iommu.o
 obj-$(CONFIG_MMIO_NVRAM)	+= mmio_nvram.o
 obj-$(CONFIG_PPC_83xx)		+= ipic.o
 obj-$(CONFIG_FSL_SOC)		+= fsl_soc.o
+obj-$(CONFIG_PPC_TODC)		+= todc.o
 obj-$(CONFIG_TSI108_BRIDGE)	+= tsi108_pci.o tsi108_dev.o
diff --git a/arch/powerpc/sysdev/todc.c b/arch/powerpc/sysdev/todc.c
new file mode 100644
index 0000000..0a65980
--- /dev/null
+++ b/arch/powerpc/sysdev/todc.c
@@ -0,0 +1,392 @@
+/*
+ * 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.
+ *
+ * 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 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.
+ */
+void
+todc_get_rtc_time(struct rtc_time *tm)
+{
+	uint	year = 0, mon = 0, mday = 0, hour = 0, min = 0, sec = 0;
+	uint	limit, i;
+	u_char	save_control, uip = 0;
+	extern void GregorianDay(struct rtc_time *);
+
+	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;
+		mday = 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(mday);
+		BCD_TO_BIN(mon);
+		BCD_TO_BIN(year);
+	}
+
+	if ((year + 1900) < 1970) {
+		year += 100;
+	}
+
+	tm->tm_sec = sec;
+	tm->tm_min = min;
+	tm->tm_hour = hour;
+	tm->tm_mday = mday;
+	tm->tm_mon = mon;
+	tm->tm_year = year;
+
+	GregorianDay(tm);
+}
+
+int
+todc_set_rtc_time(struct rtc_time *tm)
+{
+	u_char save_control, save_freq_select = 0;
+
+	spin_lock(&rtc_lock);
+	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);
+	}
+
+	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;
+}