[U-Boot] [PATCH] rtc: imxdi: Initial support
Benoît Thébaudeau
benoit.thebaudeau at advansee.com
Fri Jul 20 16:24:38 CEST 2012
Add support for Freescale's i.MX DryIce RTC, present on i.MX25.
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau at advansee.com>
Cc: Wolfgang Denk <wd at denx.de>
Cc: Stefano Babic <sbabic at denx.de>
---
.../drivers/rtc/Makefile | 1 +
/dev/null => u-boot-66714b1/drivers/rtc/imxdi.c | 224 ++++++++++++++++++++
2 files changed, 225 insertions(+)
create mode 100644 u-boot-66714b1/drivers/rtc/imxdi.c
diff --git u-boot-66714b1.orig/drivers/rtc/Makefile u-boot-66714b1/drivers/rtc/Makefile
index faf4fcd..aeeea37 100644
--- u-boot-66714b1.orig/drivers/rtc/Makefile
+++ u-boot-66714b1/drivers/rtc/Makefile
@@ -43,6 +43,7 @@ COBJS-$(CONFIG_RTC_DS164x) += ds164x.o
COBJS-$(CONFIG_RTC_DS174x) += ds174x.o
COBJS-$(CONFIG_RTC_DS3231) += ds3231.o
COBJS-$(CONFIG_RTC_FTRTC010) += ftrtc010.o
+COBJS-$(CONFIG_RTC_IMXDI) += imxdi.o
COBJS-$(CONFIG_RTC_ISL1208) += isl1208.o
COBJS-$(CONFIG_RTC_M41T11) += m41t11.o
COBJS-$(CONFIG_RTC_M41T60) += m41t60.o
diff --git u-boot-66714b1/drivers/rtc/imxdi.c u-boot-66714b1/drivers/rtc/imxdi.c
new file mode 100644
index 0000000..c2be842
--- /dev/null
+++ u-boot-66714b1/drivers/rtc/imxdi.c
@@ -0,0 +1,224 @@
+/*
+ * (C) Copyright 2009-2012 ADVANSEE
+ * Benoît Thébaudeau <benoit.thebaudeau at advansee.com>
+ *
+ * Based on the Linux rtc-imxdi.c driver, which is:
+ * Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2010 Orex Computed Radiography
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that 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
+ */
+
+/*
+ * Date & Time support for Freescale i.MX DryIce RTC
+ */
+
+#include <common.h>
+#include <command.h>
+#include <rtc.h>
+
+#if defined(CONFIG_CMD_DATE)
+
+#include <asm/io.h>
+#include <asm/arch/imx-regs.h>
+
+/* DryIce Register Definitions */
+
+#define DTCMR 0x00 /* Time Counter MSB Reg */
+#define DTCLR 0x04 /* Time Counter LSB Reg */
+
+#define DCAMR 0x08 /* Clock Alarm MSB Reg */
+#define DCALR 0x0c /* Clock Alarm LSB Reg */
+#define DCAMR_UNSET 0xFFFFFFFF /* doomsday - 1 sec */
+
+#define DCR 0x10 /* Control Reg */
+#define DCR_TCE (1 << 3) /* Time Counter Enable */
+
+#define DSR 0x14 /* Status Reg */
+#define DSR_WBF (1 << 10) /* Write Busy Flag */
+#define DSR_WNF (1 << 9) /* Write Next Flag */
+#define DSR_WCF (1 << 8) /* Write Complete Flag */
+#define DSR_WEF (1 << 7) /* Write Error Flag */
+#define DSR_CAF (1 << 4) /* Clock Alarm Flag */
+#define DSR_NVF (1 << 1) /* Non-Valid Flag */
+#define DSR_SVF (1 << 0) /* Security Violation Flag */
+
+#define DIER 0x18 /* Interrupt Enable Reg */
+#define DIER_WNIE (1 << 9) /* Write Next Interrupt Enable */
+#define DIER_WCIE (1 << 8) /* Write Complete Interrupt Enable */
+#define DIER_WEIE (1 << 7) /* Write Error Interrupt Enable */
+#define DIER_CAIE (1 << 4) /* Clock Alarm Interrupt Enable */
+
+/*
+ * This function attempts to clear the dryice write-error flag.
+ *
+ * A dryice write error is similar to a bus fault and should not occur in
+ * normal operation. Clearing the flag requires another write, so the root
+ * cause of the problem may need to be fixed before the flag can be cleared.
+ */
+static void clear_write_error(void)
+{
+ int cnt;
+
+ puts("### Warning: RTC - Register write error!\n");
+
+ /* clear the write error flag */
+ __raw_writel(DSR_WEF, IMX_DRYICE_BASE + DSR);
+
+ /* wait for it to take effect */
+ for (cnt = 0; cnt < 1000; cnt++) {
+ if ((__raw_readl(IMX_DRYICE_BASE + DSR) & DSR_WEF) == 0)
+ return;
+ udelay(10);
+ }
+ puts("### Error: RTC - Cannot clear write-error flag!\n");
+}
+
+/*
+ * Write a dryice register and wait until it completes.
+ *
+ * This function uses interrupt flags to determine when the
+ * write has completed.
+ */
+static int di_write_wait(u32 val, int reg)
+{
+ int cnt;
+ int ret = 0;
+ int rc = 0;
+
+ /* do the register write */
+ __raw_writel(val, IMX_DRYICE_BASE + reg);
+
+ /* wait for the write to finish */
+ for (cnt = 0; cnt < 100; cnt++) {
+ if ((__raw_readl(IMX_DRYICE_BASE + DSR) &
+ (DSR_WCF | DSR_WEF)) != 0) {
+ ret = 1;
+ break;
+ }
+ udelay(10);
+ }
+ if (ret == 0)
+ printf("### Warning: RTC - Write-wait timeout "
+ "val = 0x%.8x reg = 0x%.8x\n", val, reg);
+
+ /* check for write error */
+ if (__raw_readl(IMX_DRYICE_BASE + DSR) & DSR_WEF) {
+ clear_write_error();
+ rc = -1;
+ }
+
+ return rc;
+}
+
+/*
+ * Initialize dryice hardware
+ */
+static int di_init(void)
+{
+ int rc = 0;
+
+ /* mask all interrupts */
+ __raw_writel(0, IMX_DRYICE_BASE + DIER);
+
+ /* put dryice into valid state */
+ if (__raw_readl(IMX_DRYICE_BASE + DSR) & DSR_NVF) {
+ rc = di_write_wait(DSR_NVF | DSR_SVF, DSR);
+ if (rc)
+ goto err;
+ }
+
+ /* initialize alarm */
+ rc = di_write_wait(DCAMR_UNSET, DCAMR);
+ if (rc)
+ goto err;
+ rc = di_write_wait(0, DCALR);
+ if (rc)
+ goto err;
+
+ /* clear alarm flag */
+ if (__raw_readl(IMX_DRYICE_BASE + DSR) & DSR_CAF) {
+ rc = di_write_wait(DSR_CAF, DSR);
+ if (rc)
+ goto err;
+ }
+
+ /* the timer won't count if it has never been written to */
+ if (__raw_readl(IMX_DRYICE_BASE + DTCMR) == 0) {
+ rc = di_write_wait(0, DTCMR);
+ if (rc)
+ goto err;
+ }
+
+ /* start keeping time */
+ if (!(__raw_readl(IMX_DRYICE_BASE + DCR) & DCR_TCE)) {
+ rc = di_write_wait(__raw_readl(IMX_DRYICE_BASE + DCR) | DCR_TCE,
+ DCR);
+ if (rc)
+ goto err;
+ }
+
+ return 0;
+
+err:
+ return rc;
+}
+
+int rtc_get(struct rtc_time *tmp)
+{
+ unsigned long now;
+ int rc;
+
+ rc = di_init();
+ if (rc)
+ goto err;
+
+ now = __raw_readl(IMX_DRYICE_BASE + DTCMR);
+ to_tm(now, tmp);
+
+err:
+ return rc;
+}
+
+int rtc_set(struct rtc_time *tmp)
+{
+ unsigned long now;
+ int rc;
+
+ rc = di_init();
+ if (rc)
+ goto err;
+
+ now = mktime(tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
+ tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+ /* zero the fractional part first */
+ rc = di_write_wait(0, DTCLR);
+ if (rc == 0)
+ rc = di_write_wait(now, DTCMR);
+
+err:
+ return rc;
+}
+
+void rtc_reset(void)
+{
+ di_init();
+}
+
+#endif
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