Messages in this thread | | | Date | Sat, 5 Jun 2010 23:08:46 +0800 | Subject | Re: [rtc-linux] [PATCH] rtc: driver for the DryIce block found in i.MX25 chips | From | Wan ZongShun <> |
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Hi Baruch ,
Some minor comments below:
2010/6/2 Baruch Siach <baruch@tkos.co.il>: > This driver is based on code from Freescale which accompanies their i.MX25 PDK > board, with some cleanup. > > Signed-off-by: Baruch Siach <baruch@tkos.co.il> > Cc: Alessandro Zummo <a.zummo@towertech.it> > --- > > I'm sending this to LKML also, since the RTC maintainer has been silent since I > sent v3 of this driver three months ago. If you know any better way to push > this driver upstream, please let me know. > > Changes v3 -> v4: > > Merge in a patch fixing an "irq: nobody cared" race. > > Changes v2 -> v3: > > Add spaces around the '+' operator as suggested by Alessandro Zummo and Lothar > Waßmann. > > Address other comments of Alessandro Zummo: > > * add implementation of the alarm_irq_enable rtc op > * use devres in .probe > * remove unneeded initializations > > Changes v1 -> v2: > > Address the comments of Alessandro Zummo: > > * remove the .ioctl implementation > * implement .set_mmss instead of .set_time > * reorder the .probe implementation > * make sure not to have enabled interrupts when registering or > unregistering the rtc device > * add MODULE_AUTHOR() with my email > > Address the comment of Lothar Waßmann: > > * return PTR_ERR on clk_get failure > > Slightly change MODULE_DESCRIPTION(). > Use timeout which is independent of HZ for wait_event_interruptible_timeout(). > > drivers/rtc/Kconfig | 10 + > drivers/rtc/Makefile | 1 + > drivers/rtc/rtc-imxdi.c | 520 +++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 531 insertions(+), 0 deletions(-) > create mode 100644 drivers/rtc/rtc-imxdi.c > > diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig > index 10ba12c..f7dab3b 100644 > --- a/drivers/rtc/Kconfig > +++ b/drivers/rtc/Kconfig > @@ -537,6 +537,16 @@ config RTC_DRV_MSM6242 > This driver can also be built as a module. If so, the module > will be called rtc-msm6242. > > +config RTC_DRV_IMXDI > + tristate "Freescale IMX DryIce Real Time Clock" > + depends on ARCH_MX25 > + depends on RTC_CLASS > + help > + Support for Freescale IMX DryIce RTC > + > + This driver can also be built as a module, if so, the module > + will be called "rtc-imxdi". > + > config RTC_MXC > tristate "Freescale MXC Real Time Clock" > depends on ARCH_MXC > diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile > index 5adbba7..e0f6fd5 100644 > --- a/drivers/rtc/Makefile > +++ b/drivers/rtc/Makefile > @@ -46,6 +46,7 @@ obj-$(CONFIG_RTC_DRV_EFI) += rtc-efi.o > obj-$(CONFIG_RTC_DRV_EP93XX) += rtc-ep93xx.o > obj-$(CONFIG_RTC_DRV_FM3130) += rtc-fm3130.o > obj-$(CONFIG_RTC_DRV_GENERIC) += rtc-generic.o > +obj-$(CONFIG_RTC_DRV_IMXDI) += rtc-imxdi.o > obj-$(CONFIG_RTC_DRV_ISL1208) += rtc-isl1208.o > obj-$(CONFIG_RTC_DRV_M41T80) += rtc-m41t80.o > obj-$(CONFIG_RTC_DRV_M41T94) += rtc-m41t94.o > diff --git a/drivers/rtc/rtc-imxdi.c b/drivers/rtc/rtc-imxdi.c > new file mode 100644 > index 0000000..7f207cd > --- /dev/null > +++ b/drivers/rtc/rtc-imxdi.c > @@ -0,0 +1,520 @@ > +/* > + * Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved. > + * Copyright 2010 Orex Computed Radiography > + */ > + > +/* > + * 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. > + */ > + > +#include <linux/io.h> > +#include <linux/clk.h> > +#include <linux/delay.h> > +#include <linux/module.h> > +#include <linux/platform_device.h> > +#include <linux/rtc.h> > +#include <linux/workqueue.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 */ > + > +/** > + * struct imxdi_dev - private imxdi rtc data > + * @pdev: pionter to platform dev > + * @rtc: pointer to rtc struct > + * @ioaddr: IO registers pointer > + * @irq: dryice normal interrupt > + * @clk: input reference clock > + * @dsr: copy of the DSR register > + * @irq_lock: interrupt enable register (DIER) lock > + * @write_wait: registers write complete queue > + * @write_mutex: serialize registers write > + * @work: schedule alarm work > + */ > +struct imxdi_dev { > + struct platform_device *pdev; > + struct rtc_device *rtc; > + void __iomem *ioaddr; > + int irq; > + struct clk *clk; > + u32 dsr; > + spinlock_t irq_lock; > + wait_queue_head_t write_wait; > + struct mutex write_mutex; > + struct work_struct work; > +}; > + > +/* > + * enable a dryice interrupt > + */ > +static inline void di_int_enable(struct imxdi_dev *imxdi, u32 intr) > +{ > + unsigned long flags; > + > + spin_lock_irqsave(&imxdi->irq_lock, flags); > + __raw_writel(__raw_readl(imxdi->ioaddr + DIER) | intr, > + imxdi->ioaddr + DIER); > + spin_unlock_irqrestore(&imxdi->irq_lock, flags); > +} > + > +/* > + * disable a dryice interrupt > + */ > +static inline void di_int_disable(struct imxdi_dev *imxdi, u32 intr) > +{ > + unsigned long flags; > + > + spin_lock_irqsave(&imxdi->irq_lock, flags); > + __raw_writel(__raw_readl(imxdi->ioaddr + DIER) & ~intr, > + imxdi->ioaddr + DIER); > + spin_unlock_irqrestore(&imxdi->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 imxdi_dev *imxdi) > +{ > + int cnt; > + > + dev_warn(&imxdi->pdev->dev, "WARNING: Register write error!\n"); > + > + for (;;) { > + /* clear the write error flag */ > + __raw_writel(DSR_WEF, imxdi->ioaddr + DSR); > + > + /* wait for it to take effect */ > + for (cnt = 0; cnt < 100; cnt++) { > + if ((__raw_readl(imxdi->ioaddr + DSR) & DSR_WEF) == 0) > + return; > + udelay(10); > + } > + dev_err(&imxdi->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 imxdi_dev *imxdi, u32 val, int reg) > +{ > + int ret; > + int rc = 0; > + > + /* serialize register writes */ > + mutex_lock(&imxdi->write_mutex); > + > + /* enable the write-complete interrupt */ > + di_int_enable(imxdi, DIER_WCIE); > + > + imxdi->dsr = 0; > + > + /* do the register write */ > + __raw_writel(val, imxdi->ioaddr + reg); > + > + /* wait for the write to finish */ > + ret = wait_event_interruptible_timeout(imxdi->write_wait, > + imxdi->dsr & (DSR_WCF | DSR_WEF), msecs_to_jiffies(1)); > + if (ret == 0) > + dev_warn(&imxdi->pdev->dev, > + "Write-wait timeout " > + "val = 0x%08x reg = 0x%08x\n", val, reg); > + > + /* check for write error */ > + if (imxdi->dsr & DSR_WEF) { > + clear_write_error(imxdi); > + rc = -EIO; > + } > + mutex_unlock(&imxdi->write_mutex); > + return rc; > +} > + > +/* > + * 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 imxdi_dev *imxdi = dev_get_drvdata(dev); > + unsigned long now; > + > + now = __raw_readl(imxdi->ioaddr + DTCMR); > + rtc_time_to_tm(now, tm); > +
When we want to return a tm value, call rtc_valid_tm() to check the tm that is a good habit.
> + return 0; > +} > + > +/* > + * set the seconds portion of dryice time counter and clear the > + * fractional part. > + */ > +static int dryice_rtc_set_mmss(struct device *dev, unsigned long secs) > +{ > + struct imxdi_dev *imxdi = dev_get_drvdata(dev); > + int rc; > + > + /* zero the fractional part first */ > + rc = di_write_wait(imxdi, 0, DTCLR); > + if (rc == 0) > + rc = di_write_wait(imxdi, secs, DTCMR); > + > + return rc; > +} > + > +static int dryice_rtc_alarm_irq_enable(struct device *dev, > + unsigned int enabled) > +{ > + struct imxdi_dev *imxdi = dev_get_drvdata(dev); > + > + if (enabled) > + di_int_enable(imxdi, DIER_CAIE); > + else > + di_int_disable(imxdi, DIER_CAIE); > + > + return 0; > +} > + > +/* > + * 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 imxdi_dev *imxdi = dev_get_drvdata(dev); > + u32 dcamr; > + > + dcamr = __raw_readl(imxdi->ioaddr + DCAMR); > + rtc_time_to_tm(dcamr, &alarm->time); > + > + /* alarm is enabled if the interrupt is enabled */ > + alarm->enabled = (__raw_readl(imxdi->ioaddr + DIER) & DIER_CAIE) != 0; > + > + /* don't allow the DSR read to mess up DSR_WCF */ > + mutex_lock(&imxdi->write_mutex); > + > + /* alarm is pending if the alarm flag is set */ > + alarm->pending = (__raw_readl(imxdi->ioaddr + DSR) & DSR_CAF) != 0; > + > + mutex_unlock(&imxdi->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 imxdi_dev *imxdi = dev_get_drvdata(dev); > + unsigned long now; > + unsigned long alarm_time; > + int rc; > + > + rc = rtc_tm_to_time(&alarm->time, &alarm_time); > + if (rc) > + return rc; > + > + /* don't allow setting alarm in the past */ > + now = __raw_readl(imxdi->ioaddr + DTCMR); > + if (alarm_time < now) > + return -EINVAL; > + > + /* write the new alarm time */ > + rc = di_write_wait(imxdi, (u32)alarm_time, DCAMR); > + if (rc) > + return rc; > + > + if (alarm->enabled) > + di_int_enable(imxdi, DIER_CAIE); /* enable alarm intr */ > + else > + di_int_disable(imxdi, DIER_CAIE); /* disable alarm intr */ > + > + return 0; > +} > + > +static struct rtc_class_ops dryice_rtc_ops = { > + .read_time = dryice_rtc_read_time, > + .set_mmss = dryice_rtc_set_mmss, > + .alarm_irq_enable = dryice_rtc_alarm_irq_enable, > + .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 imxdi_dev *imxdi = dev_id; > + u32 dsr, dier; > + irqreturn_t rc = IRQ_NONE; > + > + dier = __raw_readl(imxdi->ioaddr + 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(&imxdi->write_wait.task_list)) > + return rc; > + > + /* DSR_WCF clears itself on DSR read */ > + dsr = __raw_readl(imxdi->ioaddr + DSR); > + if ((dsr & (DSR_WCF | DSR_WEF))) { > + /* mask the interrupt */ > + di_int_disable(imxdi, DIER_WCIE); > + > + /* save the dsr value for the wait queue */ > + imxdi->dsr |= dsr; > + > + wake_up_interruptible(&imxdi->write_wait); > + rc = IRQ_HANDLED; > + } > + } > + > + /* handle the alarm case */ > + if ((dier & DIER_CAIE)) { > + /* DSR_WCF clears itself on DSR read */ > + dsr = __raw_readl(imxdi->ioaddr + DSR); > + if (dsr & DSR_CAF) { > + /* mask the interrupt */ > + di_int_disable(imxdi, DIER_CAIE); > + > + /* finish alarm in user context */ > + schedule_work(&imxdi->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 imxdi_dev *imxdi = container_of(work, > + struct imxdi_dev, work); > + > + /* dismiss the interrupt (ignore error) */ > + di_write_wait(imxdi, DSR_CAF, DSR); > + > + /* > + * 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(imxdi->rtc, 1, RTC_AF | RTC_IRQF); > + local_irq_enable();
Are local_irq_disable() and al_irq_enable() necessary?
RTC ‘rtc_update_irq’ seem to have called 'spin_lock_irqsave' , where local irq will be disable.
> +} > + > +/* > + * probe for dryice rtc device > + */ > +static int dryice_rtc_probe(struct platform_device *pdev) > +{ > + struct resource *res; > + struct imxdi_dev *imxdi; > + int rc; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + if (!res) > + return -ENODEV; > + > + imxdi = devm_kzalloc(&pdev->dev, sizeof(*imxdi), GFP_KERNEL); > + if (!imxdi) > + return -ENOMEM; > + > + imxdi->pdev = pdev; > + > + if (!devm_request_mem_region(&pdev->dev, res->start, resource_size(res), > + pdev->name)) > + return -EBUSY; > + > + imxdi->ioaddr = devm_ioremap(&pdev->dev, res->start, > + resource_size(res)); > + if (imxdi->ioaddr == NULL) > + return -ENOMEM; > + > + imxdi->irq = platform_get_irq(pdev, 0); > + if (imxdi->irq < 0) > + return imxdi->irq; > + > + init_waitqueue_head(&imxdi->write_wait); > + > + INIT_WORK(&imxdi->work, dryice_work); > + > + mutex_init(&imxdi->write_mutex); > + > + imxdi->clk = clk_get(&pdev->dev, NULL); > + if (IS_ERR(imxdi->clk)) > + return PTR_ERR(imxdi->clk); > + clk_enable(imxdi->clk); > + > + /* > + * Initialize dryice hardware > + */ > + > + /* mask all interrupts */ > + __raw_writel(0, imxdi->ioaddr + DIER); > + > + rc = devm_request_irq(&pdev->dev, imxdi->irq, dryice_norm_irq, > + IRQF_SHARED, pdev->name, imxdi); > + if (rc) { > + dev_warn(&pdev->dev, "interrupt not available.\n"); > + goto err; > + } > + > + /* put dryice into valid state */ > + if (__raw_readl(imxdi->ioaddr + DSR) & DSR_NVF) { > + rc = di_write_wait(imxdi, DSR_NVF | DSR_SVF, DSR); > + if (rc) > + goto err; > + } > + > + /* initialize alarm */ > + rc = di_write_wait(imxdi, DCAMR_UNSET, DCAMR); > + if (rc) > + goto err; > + rc = di_write_wait(imxdi, 0, DCALR); > + if (rc) > + goto err; > + > + /* clear alarm flag */ > + if (__raw_readl(imxdi->ioaddr + DSR) & DSR_CAF) { > + rc = di_write_wait(imxdi, DSR_CAF, DSR); > + if (rc) > + goto err; > + } > + > + /* the timer won't count if it has never been written to */ > + if (__raw_readl(imxdi->ioaddr + DTCMR) == 0) { > + rc = di_write_wait(imxdi, 0, DTCMR); > + if (rc) > + goto err; > + } > + > + /* start keeping time */ > + if (!(__raw_readl(imxdi->ioaddr + DCR) & DCR_TCE)) { > + rc = di_write_wait(imxdi, > + __raw_readl(imxdi->ioaddr + DCR) | DCR_TCE, > + DCR); > + if (rc) > + goto err; > + } > + > + imxdi->rtc = rtc_device_register(pdev->name, &pdev->dev, > + &dryice_rtc_ops, THIS_MODULE); > + if (IS_ERR(imxdi->rtc)) { > + rc = PTR_ERR(imxdi->rtc); > + goto err; > + } > + platform_set_drvdata(pdev, imxdi); > + > + return 0; > + > +err: > + clk_disable(imxdi->clk); > + clk_put(imxdi->clk); > + > + return rc; > +} > + > +static int __devexit dryice_rtc_remove(struct platform_device *pdev) > +{ > + struct imxdi_dev *imxdi = platform_get_drvdata(pdev); > + > + flush_scheduled_work(); > + > + /* mask all interrupts */ > + __raw_writel(0, imxdi->ioaddr + DIER); > + > + rtc_device_unregister(imxdi->rtc); > + > + clk_disable(imxdi->clk); > + clk_put(imxdi->clk); > + > + return 0; > +} > + > +static struct platform_driver dryice_rtc_driver = { > + .driver = { > + .name = "imxdi_rtc", > + .owner = THIS_MODULE, > + }, > + .probe = dryice_rtc_probe, > + .remove = __devexit_p(dryice_rtc_remove), > +}; > + > +static int __init dryice_rtc_init(void) > +{ > + return platform_driver_register(&dryice_rtc_driver);
platform_driver_probe will be much better here.
> +} > + > +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_AUTHOR("Baruch Siach <baruch@tkos.co.il>"); > +MODULE_DESCRIPTION("IMX DryIce Realtime Clock Driver (RTC)"); > +MODULE_LICENSE("GPL"); > -- > 1.7.1 > > -- > You received this message because you are subscribed to "rtc-linux". > Membership options at http://groups.google.com/group/rtc-linux . > Please read http://groups.google.com/group/rtc-linux/web/checklist > before submitting a driver.
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