From 2731b2eadeaa141e6f305fa8086106608112bbaa Mon Sep 17 00:00:00 2001 From: Roshni Shah Date: Mon, 14 Mar 2011 06:49:42 -0400 Subject: Add support for the i.MX53 QSB This patch seems to have originated from the 11.01.00 release from Freescale, which is no longer available except through the gitweb interface from Freescale. http://opensource.freescale.com/git?p=imx/linux-2.6-imx.git;a=commit;h=27fdf7bae11978d21e8aba09bb635f49b07edd4a --- drivers/rtc/rtc-imxdi.c | 581 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 581 insertions(+) create mode 100644 drivers/rtc/rtc-imxdi.c (limited to 'drivers/rtc/rtc-imxdi.c') diff --git a/drivers/rtc/rtc-imxdi.c b/drivers/rtc/rtc-imxdi.c new file mode 100644 index 000000000000..599c525a9f66 --- /dev/null +++ b/drivers/rtc/rtc-imxdi.c @@ -0,0 +1,581 @@ +/* + * Copyright 2008-2010 Freescale Semiconductor, Inc. All Rights Reserved. + */ + +/* + * The code contained herein is licensed under the GNU General Public + * License. You may obtain a copy of the GNU General Public License + * Version 2 or later at the following locations: + * + * http://www.opensource.org/licenses/gpl-license.html + * http://www.gnu.org/copyleft/gpl.html + */ + +/* based on rtc-mc13892.c */ + +/* + * This driver uses the 47-bit 32 kHz counter in the Freescale DryIce block + * to implement a Linux RTC. Times and alarms are truncated to seconds. + * Since the RTC framework performs API locking via rtc->ops_lock the + * only simultaneous accesses we need to deal with is updating DryIce + * registers while servicing an alarm. + * + * Note that reading the DSR (DryIce Status Register) automatically clears + * the WCF (Write Complete Flag). All DryIce writes are synchronized to the + * LP (Low Power) domain and set the WCF upon completion. Writes to the + * DIER (DryIce Interrupt Enable Register) are the only exception. These + * occur at normal bus speeds and do not set WCF. Periodic interrupts are + * not supported by the hardware. + */ + +/* #define DEBUG */ +/* #define DI_DEBUG_REGIO */ + +#include +#include +#include +#include +#include +#include +#include +#include + +/* 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 */ + +#ifndef DI_DEBUG_REGIO +/* dryice read register */ +#define di_read(pdata, reg) __raw_readl((pdata)->ioaddr + (reg)) + +/* dryice write register */ +#define di_write(pdata, val, reg) __raw_writel((val), (pdata)->ioaddr + (reg)) +#else +/* dryice read register - debug version */ +static inline u32 di_read(struct rtc_drv_data *pdata, int reg) +{ + u32 val = __raw_readl(pdata->ioaddr + reg); + pr_info("di_read(0x%02x) = 0x%08x\n", reg, val); + return val; +} + +/* dryice write register - debug version */ +static inline void di_write(struct rtc_drv_data *pdata, u32 val, int reg) +{ + printk(KERN_INFO "di_write(0x%08x, 0x%02x)\n", val, reg); + __raw_writel(val, pdata->ioaddr + reg); +} +#endif + +/* + * dryice write register with wait and error handling. + * all registers, except for DIER, should use this method. + */ +#define di_write_wait_err(pdata, val, reg, rc, label) \ + do { \ + if (di_write_wait((pdata), (val), (reg))) { \ + rc = -EIO; \ + goto label; \ + } \ + } while (0) + +struct rtc_drv_data { + struct platform_device *pdev; /* pointer to platform dev */ + struct rtc_device *rtc; /* pointer to rtc struct */ + unsigned long baseaddr; /* physical bass address */ + void __iomem *ioaddr; /* virtual base address */ + int size; /* size of register region */ + int irq; /* dryice normal irq */ + struct clk *clk; /* dryice clock control */ + u32 dsr; /* copy of dsr reg from isr */ + spinlock_t irq_lock; /* irq resource lock */ + wait_queue_head_t write_wait; /* write-complete queue */ + struct mutex write_mutex; /* force reg writes to be sequential */ + struct work_struct work; /* schedule alarm work */ +}; + +/* + * enable a dryice interrupt + */ +static inline void di_int_enable(struct rtc_drv_data *pdata, u32 intr) +{ + unsigned long flags; + + spin_lock_irqsave(&pdata->irq_lock, flags); + di_write(pdata, di_read(pdata, DIER) | intr, DIER); + spin_unlock_irqrestore(&pdata->irq_lock, flags); +} + +/* + * disable a dryice interrupt + */ +static inline void di_int_disable(struct rtc_drv_data *pdata, u32 intr) +{ + unsigned long flags; + + spin_lock_irqsave(&pdata->irq_lock, flags); + di_write(pdata, di_read(pdata, DIER) & ~intr, DIER); + spin_unlock_irqrestore(&pdata->irq_lock, flags); +} + +/* + * 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(struct rtc_drv_data *pdata) +{ + int cnt; + + dev_warn(&pdata->pdev->dev, "WARNING: Register write error!\n"); + + for (;;) { + /* clear the write error flag */ + di_write(pdata, DSR_WEF, DSR); + + /* wait for it to take effect */ + for (cnt = 0; cnt < 100; cnt++) { + if ((di_read(pdata, DSR) & DSR_WEF) == 0) + return; + udelay(10); + } + dev_err(&pdata->pdev->dev, + "ERROR: Cannot clear write-error flag!\n"); + } +} + +/* + * Write a dryice register and wait until it completes. + * + * This function uses interrupts to determine when the + * write has completed. + */ +static int di_write_wait(struct rtc_drv_data *pdata, u32 val, int reg) +{ + int ret; + int rc = 0; + + /* serialize register writes */ + mutex_lock(&pdata->write_mutex); + + /* enable the write-complete interrupt */ + di_int_enable(pdata, DIER_WCIE); + + pdata->dsr = 0; + + /* do the register write */ + di_write(pdata, val, reg); + + /* wait for the write to finish */ + ret = wait_event_interruptible_timeout(pdata->write_wait, + pdata->dsr & (DSR_WCF | DSR_WEF), + 1 * HZ); + if (ret == 0) + dev_warn(&pdata->pdev->dev, "Write-wait timeout\n"); + + /* check for write error */ + if (pdata->dsr & DSR_WEF) { + clear_write_error(pdata); + rc = -EIO; + } + mutex_unlock(&pdata->write_mutex); + return rc; +} + +/* + * rtc device ioctl + * + * The rtc framework handles the basic rtc ioctls on behalf + * of the driver by calling the functions registered in the + * rtc_ops structure. + */ +static int dryice_rtc_ioctl(struct device *dev, unsigned int cmd, + unsigned long arg) +{ + struct rtc_drv_data *pdata = dev_get_drvdata(dev); + + dev_dbg(dev, "%s(0x%x)\n", __func__, cmd); + switch (cmd) { + case RTC_AIE_OFF: /* alarm disable */ + di_int_disable(pdata, DIER_CAIE); + return 0; + + case RTC_AIE_ON: /* alarm enable */ + di_int_enable(pdata, DIER_CAIE); + return 0; + } + return -ENOIOCTLCMD; +} + +/* + * read the seconds portion of the current time from the dryice time counter + */ +static int dryice_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct rtc_drv_data *pdata = dev_get_drvdata(dev); + unsigned long now; + + dev_dbg(dev, "%s\n", __func__); + now = di_read(pdata, DTCMR); + rtc_time_to_tm(now, tm); + + return 0; +} + +/* + * set the seconds portion of dryice time counter and clear the + * fractional part. + */ +static int dryice_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct rtc_drv_data *pdata = dev_get_drvdata(dev); + unsigned long now; + int rc; + + dev_dbg(dev, "%s\n", __func__); + rc = rtc_tm_to_time(tm, &now); + if (rc == 0) { + /* zero the fractional part first */ + di_write_wait_err(pdata, 0, DTCLR, rc, err); + di_write_wait_err(pdata, now, DTCMR, rc, err); + } +err: + return rc; +} + +/* + * read the seconds portion of the alarm register. + * the fractional part of the alarm register is always zero. + */ +static int dryice_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct rtc_drv_data *pdata = dev_get_drvdata(dev); + u32 dcamr; + + dev_dbg(dev, "%s\n", __func__); + dcamr = di_read(pdata, DCAMR); + rtc_time_to_tm(dcamr, &alarm->time); + + /* alarm is enabled if the interrupt is enabled */ + alarm->enabled = (di_read(pdata, DIER) & DIER_CAIE) != 0; + + /* don't allow the DSR read to mess up DSR_WCF */ + mutex_lock(&pdata->write_mutex); + + /* alarm is pending if the alarm flag is set */ + alarm->pending = (di_read(pdata, DSR) & DSR_CAF) != 0; + + mutex_unlock(&pdata->write_mutex); + + return 0; +} + +/* + * set the seconds portion of dryice alarm register + */ +static int dryice_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct rtc_drv_data *pdata = dev_get_drvdata(dev); + unsigned long now; + unsigned long alarm_time; + int rc; + + dev_dbg(dev, "%s\n", __func__); + rc = rtc_tm_to_time(&alarm->time, &alarm_time); + if (rc) + return rc; + + /* don't allow setting alarm in the past */ + now = di_read(pdata, DTCMR); + if (alarm_time < now) + return -EINVAL; + + /* write the new alarm time */ + di_write_wait_err(pdata, (u32)alarm_time, DCAMR, rc, err); + + if (alarm->enabled) + di_int_enable(pdata, DIER_CAIE); /* enable alarm intr */ + else + di_int_disable(pdata, DIER_CAIE); /* disable alarm intr */ +err: + return rc; +} + +static struct rtc_class_ops dryice_rtc_ops = { + .ioctl = dryice_rtc_ioctl, + .read_time = dryice_rtc_read_time, + .set_time = dryice_rtc_set_time, + .read_alarm = dryice_rtc_read_alarm, + .set_alarm = dryice_rtc_set_alarm, +}; + +/* + * dryice "normal" interrupt handler + */ +static irqreturn_t dryice_norm_irq(int irq, void *dev_id) +{ + struct rtc_drv_data *pdata = dev_id; + u32 dsr, dier; + irqreturn_t rc = IRQ_NONE; + + dier = di_read(pdata, DIER); + + /* handle write complete and write error cases */ + if ((dier & DIER_WCIE)) { + /*If the write wait queue is empty then there is no pending + operations. It means the interrupt is for DryIce -Security. + IRQ must be returned as none.*/ + if (list_empty_careful(&pdata->write_wait.task_list)) + return rc; + + /* DSR_WCF clears itself on DSR read */ + dsr = di_read(pdata, DSR); + if ((dsr & (DSR_WCF | DSR_WEF))) { + /* mask the interrupt */ + di_int_disable(pdata, DIER_WCIE); + + /* save the dsr value for the wait queue */ + pdata->dsr |= dsr; + + wake_up_interruptible(&pdata->write_wait); + rc = IRQ_HANDLED; + } + } + + /* handle the alarm case */ + if ((dier & DIER_CAIE)) { + /* DSR_WCF clears itself on DSR read */ + dsr = di_read(pdata, DSR); + if (dsr & DSR_CAF) { + /* mask the interrupt */ + di_int_disable(pdata, DIER_CAIE); + + /* finish alarm in user context */ + schedule_work(&pdata->work); + rc = IRQ_HANDLED; + } + } + return rc; +} + +/* + * post the alarm event from user context so it can sleep + * on the write completion. + */ +static void dryice_work(struct work_struct *work) +{ + struct rtc_drv_data *pdata = container_of(work, struct rtc_drv_data, + work); + int rc; + + /* dismiss the interrupt (ignore error) */ + di_write_wait_err(pdata, DSR_CAF, DSR, rc, err); +err: + /* + * pass the alarm event to the rtc framework. note that + * rtc_update_irq expects to be called with interrupts off. + */ + local_irq_disable(); + rtc_update_irq(pdata->rtc, 1, RTC_AF | RTC_IRQF); + local_irq_enable(); +} + +/* + * probe for dryice rtc device + */ +static int dryice_rtc_probe(struct platform_device *pdev) +{ + struct rtc_device *rtc; + struct resource *res; + struct rtc_drv_data *pdata = NULL; + void __iomem *ioaddr = NULL; + int rc = 0; + + dev_dbg(&pdev->dev, "%s\n", __func__); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENODEV; + + pdata = kzalloc(sizeof(*pdata), GFP_KERNEL); + if (!pdata) + return -ENOMEM; + + pdata->pdev = pdev; + pdata->irq = -1; + pdata->size = res->end - res->start + 1; + + if (!request_mem_region(res->start, pdata->size, pdev->name)) { + rc = -EBUSY; + goto err; + } + pdata->baseaddr = res->start; + ioaddr = ioremap(pdata->baseaddr, pdata->size); + if (!ioaddr) { + rc = -ENOMEM; + goto err; + } + pdata->ioaddr = ioaddr; + pdata->irq = platform_get_irq(pdev, 0); + + init_waitqueue_head(&pdata->write_wait); + + INIT_WORK(&pdata->work, dryice_work); + + mutex_init(&pdata->write_mutex); + + pdata->clk = clk_get(NULL, "dryice_clk"); + clk_enable(pdata->clk); + + if (pdata->irq >= 0) { + if (request_irq(pdata->irq, dryice_norm_irq, IRQF_SHARED, + pdev->name, pdata) < 0) { + dev_warn(&pdev->dev, "interrupt not available.\n"); + pdata->irq = -1; + goto err; + } + } + + /* + * Initialize dryice hardware + */ + + /* put dryice into valid state */ + if (di_read(pdata, DSR) & DSR_NVF) + di_write_wait_err(pdata, DSR_NVF | DSR_SVF, DSR, rc, err); + + /* mask alarm interrupt */ + di_int_disable(pdata, DIER_CAIE); + + /* initialize alarm */ + di_write_wait_err(pdata, DCAMR_UNSET, DCAMR, rc, err); + di_write_wait_err(pdata, 0, DCALR, rc, err); + + /* clear alarm flag */ + if (di_read(pdata, DSR) & DSR_CAF) + di_write_wait_err(pdata, DSR_CAF, DSR, rc, err); + + /* the timer won't count if it has never been written to */ + if (!di_read(pdata, DTCMR)) + di_write_wait_err(pdata, 0, DTCMR, rc, err); + + /* start keeping time */ + if (!(di_read(pdata, DCR) & DCR_TCE)) + di_write_wait_err(pdata, di_read(pdata, DCR) | DCR_TCE, DCR, + rc, err); + + rtc = rtc_device_register(pdev->name, &pdev->dev, + &dryice_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) { + rc = PTR_ERR(rtc); + goto err; + } + pdata->rtc = rtc; + platform_set_drvdata(pdev, pdata); + + return 0; +err: + if (pdata->rtc) + rtc_device_unregister(pdata->rtc); + + if (pdata->irq >= 0) + free_irq(pdata->irq, pdata); + + if (pdata->clk) { + clk_disable(pdata->clk); + clk_put(pdata->clk); + } + + if (pdata->ioaddr) + iounmap(pdata->ioaddr); + + if (pdata->baseaddr) + release_mem_region(pdata->baseaddr, pdata->size); + + kfree(pdata); + + return rc; +} + +static int __exit dryice_rtc_remove(struct platform_device *pdev) +{ + struct rtc_drv_data *pdata = platform_get_drvdata(pdev); + + flush_scheduled_work(); + + if (pdata->rtc) + rtc_device_unregister(pdata->rtc); + + /* mask alarm interrupt */ + di_int_disable(pdata, DIER_CAIE); + + if (pdata->irq >= 0) + free_irq(pdata->irq, pdata); + + if (pdata->clk) { + clk_disable(pdata->clk); + clk_put(pdata->clk); + } + + if (pdata->ioaddr) + iounmap(pdata->ioaddr); + + if (pdata->baseaddr) + release_mem_region(pdata->baseaddr, pdata->size); + + kfree(pdata); + + return 0; +} + +static struct platform_driver dryice_rtc_driver = { + .driver = { + .name = "imxdi_rtc", + .owner = THIS_MODULE, + }, + .probe = dryice_rtc_probe, + .remove = __exit_p(dryice_rtc_remove), +}; + +static int __init dryice_rtc_init(void) +{ + pr_info("IMXDI Realtime Clock Driver (RTC)\n"); + return platform_driver_register(&dryice_rtc_driver); +} + +static void __exit dryice_rtc_exit(void) +{ + platform_driver_unregister(&dryice_rtc_driver); +} + +module_init(dryice_rtc_init); +module_exit(dryice_rtc_exit); + +MODULE_AUTHOR("Freescale Semiconductor, Inc."); +MODULE_DESCRIPTION("IMXDI Realtime Clock Driver (RTC)"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3