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// SPDX-License-Identifier: GPL-2.0+
/*
* (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
*/
/*
* Date & Time support for Freescale i.MX DryIce RTC
*/
#include <common.h>
#include <command.h>
#include <linux/compat.h>
#include <rtc.h>
#include <linux/delay.h>
#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);
rtc_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 = rtc_mktime(tmp);
/* 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();
}
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