diff options
Diffstat (limited to 'drivers/rtc/imxdi.c')
| -rw-r--r-- | drivers/rtc/imxdi.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/rtc/imxdi.c b/drivers/rtc/imxdi.c new file mode 100644 index 0000000000..985ce93acf --- /dev/null +++ b/drivers/rtc/imxdi.c @@ -0,0 +1,244 @@ +/* + * (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 |
