--- /dev/null
+/*
+ * (C) Copyright 2009-2012 ADVANSEE
+ * Benoît Thébaudeau <benoit.thebaudeau@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 <linux/compat.h>
+#include <rtc.h>
+
+#if defined(CONFIG_CMD_DATE)
+
+#include <asm/io.h>
+#include <asm/arch/imx-regs.h>
+
+/* DryIce Register Definitions */
+
+struct imxdi_regs {
+ u32 dtcmr; /* Time Counter MSB Reg */
+ u32 dtclr; /* Time Counter LSB Reg */
+ u32 dcamr; /* Clock Alarm MSB Reg */
+ u32 dcalr; /* Clock Alarm LSB Reg */
+ u32 dcr; /* Control Reg */
+ u32 dsr; /* Status Reg */
+ u32 dier; /* Interrupt Enable Reg */
+};
+
+#define DCAMR_UNSET 0xFFFFFFFF /* doomsday - 1 sec */
+
+#define DCR_TCE (1 << 3) /* Time Counter Enable */
+
+#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_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 */
+
+/* Driver Private Data */
+
+struct imxdi_data {
+ struct imxdi_regs __iomem *regs;
+ int init_done;
+};
+
+static struct imxdi_data data;
+
+/*
+ * 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, &data.regs->dsr);
+
+ /* wait for it to take effect */
+ for (cnt = 0; cnt < 1000; cnt++) {
+ if ((__raw_readl(&data.regs->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.
+ *
+ * Use interrupt flags to determine when the write has completed.
+ */
+#define DI_WRITE_WAIT(val, reg) \
+( \
+ /* do the register write */ \
+ __raw_writel((val), &data.regs->reg), \
+ \
+ di_write_wait((val), #reg) \
+)
+static int di_write_wait(u32 val, const char *reg)
+{
+ int cnt;
+ int ret = 0;
+ int rc = 0;
+
+ /* wait for the write to finish */
+ for (cnt = 0; cnt < 100; cnt++) {
+ if ((__raw_readl(&data.regs->dsr) & (DSR_WCF | DSR_WEF)) != 0) {
+ ret = 1;
+ break;
+ }
+ udelay(10);
+ }
+ if (ret == 0)
+ printf("### Warning: RTC - Write-wait timeout "
+ "val = 0x%.8x reg = %s\n", val, reg);
+
+ /* check for write error */
+ if (__raw_readl(&data.regs->dsr) & DSR_WEF) {
+ clear_write_error();
+ rc = -1;
+ }
+
+ return rc;
+}
+
+/*
+ * Initialize dryice hardware
+ */
+static int di_init(void)
+{
+ int rc = 0;
+
+ data.regs = (struct imxdi_regs __iomem *)IMX_DRYICE_BASE;
+
+ /* mask all interrupts */
+ __raw_writel(0, &data.regs->dier);
+
+ /* put dryice into valid state */
+ if (__raw_readl(&data.regs->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(&data.regs->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(&data.regs->dtcmr) == 0) {
+ rc = DI_WRITE_WAIT(0, dtcmr);
+ if (rc)
+ goto err;
+ }
+
+ /* start keeping time */
+ if (!(__raw_readl(&data.regs->dcr) & DCR_TCE)) {
+ rc = DI_WRITE_WAIT(__raw_readl(&data.regs->dcr) | DCR_TCE, dcr);
+ if (rc)
+ goto err;
+ }
+
+ data.init_done = 1;
+ return 0;
+
+err:
+ return rc;
+}
+
+int rtc_get(struct rtc_time *tmp)
+{
+ unsigned long now;
+ int rc = 0;
+
+ if (!data.init_done) {
+ rc = di_init();
+ if (rc)
+ goto err;
+ }
+
+ now = __raw_readl(&data.regs->dtcmr);
+ to_tm(now, tmp);
+
+err:
+ return rc;
+}
+
+int rtc_set(struct rtc_time *tmp)
+{
+ unsigned long now;
+ int rc;
+
+ if (!data.init_done) {
+ 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
projects / karo-tx-uboot.git / commitdiff