Add RTC driver for ST variant of pl031

The RTC implemented on the dbx500 SoCs is a derivative of the
pl031. This driver supports the STv2 date/time layout.
It is based on Linux drivers/rtc/rtc-pl031.c

Change-Id: Iebe5973ba0627670f138631664748386b60f2b11
Signed-off-by: Michael Brandt <michael.brandt@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/6331
Reviewed-by: Carl-Johan IREKVIST <carl-johan.irekvist@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/7718
Reviewed-by: Mian Yousaf KAUKAB <mian.yousaf.kaukab@stericsson.com>

2 files changed, 213 insertions, 0 deletions

diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 772a49a90..4ae47c75e 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -56,6 +56,7 @@ COBJS-$(CONFIG_RTC_MPC5200) += mpc5xxx.o
 COBJS-$(CONFIG_RTC_MPC8xx) += mpc8xx.o
 COBJS-$(CONFIG_RTC_PCF8563) += pcf8563.o
 COBJS-$(CONFIG_RTC_PL031) += pl031.o
+COBJS-$(CONFIG_RTC_PL031_ST) += pl031_st.o
 COBJS-$(CONFIG_RTC_RS5C372A) += rs5c372.o
 COBJS-$(CONFIG_RTC_RTC4543) += rtc4543.o
 COBJS-$(CONFIG_RTC_RX8025) += rx8025.o
diff --git a/drivers/rtc/pl031_st.c b/drivers/rtc/pl031_st.c
new file mode 100644
index 000000000..c1b163de3
--- /dev/null
+++ b/drivers/rtc/pl031_st.c
@@ -0,0 +1,212 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * based on Linux drivers/rtc/rtc-pl031.c:
+ *
+ * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC
+ *
+ * Author: Deepak Saxena <dsaxena@plexity.net>
+ *
+ * Copyright 2006 (c) MontaVista Software, Inc.
+ *
+ * Author: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
+ * Copyright 2010 (c) ST-Ericsson AB
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <common.h>
+#include <command.h>
+#include <asm/io.h>
+#include <rtc.h>
+
+#if defined(CONFIG_CMD_DATE)
+
+#ifndef CONFIG_SYS_RTC_PL031_BASE
+#error CONFIG_SYS_RTC_PL031_BASE is not defined!
+#endif
+
+/*
+ * Register definitions
+ */
+#define	RTC_DR		0x00	/* Data read register */
+#define	RTC_MR		0x04	/* Match register */
+#define	RTC_LR		0x08	/* Data load register */
+#define	RTC_CR		0x0c	/* Control register */
+#define	RTC_IMSC	0x10	/* Interrupt mask and set register */
+#define	RTC_RIS		0x14	/* Raw interrupt status register */
+#define	RTC_MIS		0x18	/* Masked interrupt status register */
+#define	RTC_ICR		0x1c	/* Interrupt clear register */
+/* ST variants have additional timer functionality */
+#define RTC_TDR		0x20	/* Timer data read register */
+#define RTC_TLR		0x24	/* Timer data load register */
+#define RTC_TCR		0x28	/* Timer control register */
+#define RTC_YDR		0x30	/* Year data read register */
+#define RTC_YMR		0x34	/* Year match register */
+#define RTC_YLR		0x38	/* Year data load register */
+
+#define RTC_CR_CWEN	(1 << 26)	/* Clockwatch enable bit */
+
+/* Common bit definations for ST v2 for reading/writing time */
+#define RTC_SEC_SHIFT 0
+#define RTC_SEC_MASK (0x3F << RTC_SEC_SHIFT) /* Second [0-59] */
+#define RTC_MIN_SHIFT 6
+#define RTC_MIN_MASK (0x3F << RTC_MIN_SHIFT) /* Minute [0-59] */
+#define RTC_HOUR_SHIFT 12
+#define RTC_HOUR_MASK (0x1F << RTC_HOUR_SHIFT) /* Hour [0-23] */
+#define RTC_WDAY_SHIFT 17
+#define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */
+#define RTC_MDAY_SHIFT 20
+#define RTC_MDAY_MASK (0x1F << RTC_MDAY_SHIFT) /* Day of Month [1-31] */
+#define RTC_MON_SHIFT 25
+#define RTC_MON_MASK (0xF << RTC_MON_SHIFT) /* Month [1-12] 1=January */
+
+static int pl031_initted = 0;
+
+/*
+ * Convert Gregorian date to ST v2 RTC format.
+ */
+static int pl031_stv2_tm_to_time(struct rtc_time *tm, unsigned long *st_time,
+	unsigned long *bcd_year)
+{
+	int year = tm->tm_year;
+	int wday = tm->tm_wday;
+
+	/* wday masking is not working in hardware so wday must be valid */
+	if (wday < -1 || wday > 6) {
+		printf("invalid wday value %d\n", tm->tm_wday);
+		return -1;
+	} else if (wday == -1) {
+		/* wday is not provided, calculate it here */
+		GregorianDay(tm);
+		wday = tm->tm_wday;
+	}
+
+	*bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8);
+
+	*st_time = (tm->tm_mon << RTC_MON_SHIFT)
+			|	(tm->tm_mday << RTC_MDAY_SHIFT)
+			|	((wday + 1) << RTC_WDAY_SHIFT)
+			|	(tm->tm_hour << RTC_HOUR_SHIFT)
+			|	(tm->tm_min << RTC_MIN_SHIFT)
+			|	(tm->tm_sec << RTC_SEC_SHIFT);
+
+	return 0;
+}
+
+/*
+ * Convert ST v2 RTC format to Gregorian date.
+ */
+static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year,
+	struct rtc_time *tm)
+{
+	tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100);
+	tm->tm_mon  = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT);
+	tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT);
+	tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
+	tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT);
+	tm->tm_min  = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT);
+	tm->tm_sec  = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT);
+
+	return 0;
+}
+
+static int pl031_stv2_read_time(struct rtc_time *tm)
+{
+
+	pl031_stv2_time_to_tm(readl(CONFIG_SYS_RTC_PL031_BASE + RTC_DR),
+			readl(CONFIG_SYS_RTC_PL031_BASE + RTC_YDR), tm);
+
+	return 0;
+}
+
+static int pl031_stv2_set_time(struct rtc_time *tm)
+{
+	unsigned long time;
+	unsigned long bcd_year;
+	int ret;
+
+	ret = pl031_stv2_tm_to_time(tm, &time, &bcd_year);
+	if (ret == 0) {
+		writel(bcd_year, CONFIG_SYS_RTC_PL031_BASE + RTC_YLR);
+		writel(time, CONFIG_SYS_RTC_PL031_BASE + RTC_LR);
+	}
+	/*
+	 * The new setting is transferred to the ClockWatch counters on the
+	 * next CLK1HZ rising edge after RTC_CWDLR register has been written.
+	 */
+	udelay(1000 * 1000);
+
+	return ret;
+}
+
+/* Enable RTC Start in Control register*/
+void rtc_init(void)
+{
+	writel(readl(CONFIG_SYS_RTC_PL031_BASE + RTC_CR) | RTC_CR_CWEN,
+			CONFIG_SYS_RTC_PL031_BASE + RTC_CR);
+
+	pl031_initted = 1;
+}
+
+/*
+ * Reset the RTC. We set the date back to 1970-01-01.
+ */
+void rtc_reset(void)
+{
+	if (!pl031_initted)
+		rtc_init();
+	/* POR value, 2000-01-01 Sun */
+	writel(0x02120000, CONFIG_SYS_RTC_PL031_BASE + RTC_LR);
+	writel(0x2000, CONFIG_SYS_RTC_PL031_BASE + RTC_YLR);
+	/*
+	 * The new setting is transferred to the ClockWatch counters on the
+	 * next CLK1HZ rising edge after RTC_CWDLR register has been written.
+	 */
+	udelay(1000 * 1000);
+}
+
+/*
+ * Set the RTC
+ */
+int rtc_set(struct rtc_time *tm)
+{
+
+	if (!pl031_initted)
+		rtc_init();
+
+	if (tm == NULL) {
+		puts("Error setting the date/time\n");
+		return -1;
+	}
+
+	return pl031_stv2_set_time(tm);
+}
+
+
+/*
+ * Get the current time from the RTC
+ */
+int rtc_get(struct rtc_time *tm)
+{
+
+	if (!pl031_initted)
+		rtc_init();
+
+	if (tm == NULL) {
+		puts("Error getting the date/time\n");
+		return -1;
+	}
+
+	pl031_stv2_read_time(tm);
+
+	debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
+		tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
+		tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+	return 0;
+}
+#endif