--- /dev/null
+/*
+ * Copyright (C) 2011 Freescale Semiconductor, Inc.
+ */
+
+/*
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+/*
+ * Implementation based on rtc-ds1553.c
+ */
+
+/*!
+ * @defgroup RTC Real Time Clock (RTC) Driver
+ */
+/*!
+ * @file rtc-snvs.c
+ * @brief Secure Real Time Clock (SRTC) interface in Freescale's SNVS module
+ *
+ * This file contains Real Time Clock interface for Linux. The Freescale
+ * SNVS module's Low Power (LP) SRTC functionality is utilized in this driver,
+ * in non-secure mode.
+ *
+ * @ingroup RTC
+ */
+
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/rtc.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/sched.h>
+
+/* Register definitions */
+#define SNVS_HPSR 0x14 /* HP Status Register */
+#define SNVS_LPCR 0x38 /* LP Control Register */
+#define SNVS_LPSR 0x4C /* LP Status Register */
+#define SNVS_LPSRTCMR 0x50 /* LP Secure Real Time Counter MSB Register */
+#define SNVS_LPSRTCLR 0x54 /* LP Secure Real Time Counter LSB Register */
+#define SNVS_LPTAR 0x58 /* LP Time Alarm Register */
+#define SNVS_LPSMCMR 0x5C /* LP Secure Monotonic Counter MSB Register */
+#define SNVS_LPSMCLR 0x60 /* LP Secure Monotonic Counter LSB Register */
+#define SNVS_LPPGDR 0x64 /* LP Power Glitch Detector Register */
+#define SNVS_LPGPR 0x68 /* LP General Purpose Register */
+
+/* Bit Definitions */
+#define SNVS_HPSR_SSM_ST_MASK 0x00000F00
+#define SNVS_HPSR_SSM_ST_SHIFT 8
+
+#define SNVS_LPCR_SRTC_ENV (1 << 0)
+#define SNVS_LPCR_LPTA_EN (1 << 1)
+#define SNVS_LPCR_LPWUI_EN (1 << 3)
+
+#define SNVS_LPCR_ALL_INT_EN (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN)
+
+#define SNVS_LPSR_LPTA (1 << 0)
+
+#define SNVS_LPPGDR_INIT 0x41736166
+
+/* Other defines */
+#define SSM_ST_CHECK 0x9
+#define SSM_ST_NON_SECURE 0xB
+#define CNTR_TO_SECS_SH 15 /* Converts 47-bit counter to 32-bit seconds */
+
+struct rtc_drv_data {
+ struct rtc_device *rtc;
+ void __iomem *ioaddr;
+ unsigned long baseaddr;
+ int irq;
+ bool irq_enable;
+};
+
+static unsigned long rtc_status;
+
+static DEFINE_SPINLOCK(rtc_lock);
+
+/*!
+ * LP counter register reads should always use this function.
+ * This function reads 2 consective times from LP counter register
+ * until the 2 values match. This is to avoid reading corrupt
+ * value if the counter is in the middle of updating
+ */
+static inline u32 rtc_read_lp_counter(void __iomem *counter_reg)
+{
+ u64 read1, read2;
+ u32 counter_sec;
+
+ do {
+ /* MSB */
+ read1 = __raw_readl(counter_reg);
+ read1 <<= 32;
+ /* LSB */
+ read1 |= __raw_readl(counter_reg + 4);
+
+ /* MSB */
+ read2 = __raw_readl(counter_reg);
+ read2 <<= 32;
+ /* LSB */
+ read2 |= __raw_readl(counter_reg + 4);
+ } while (read1 != read2);
+
+ /* Convert 47-bit counter to 32-bit raw second count */
+ counter_sec = (u32) (read1 >> CNTR_TO_SECS_SH);
+ return counter_sec;
+}
+
+/*!
+ * This function does write synchronization for writes to the lp srtc block.
+ * To take care of the asynchronous CKIL clock, all writes from the IP domain
+ * will be synchronized to the CKIL domain.
+ */
+static inline void rtc_write_sync_lp(void __iomem *ioaddr)
+{
+ unsigned int i, count1, count2, count3;
+
+ /* Wait for 3 CKIL cycles */
+ for (i = 0; i < 3; i++) {
+
+ /* Do consective reads of LSB of counter to ensure integrity */
+ do {
+ count1 = __raw_readl(ioaddr + SNVS_LPSRTCLR);
+ count2 = __raw_readl(ioaddr + SNVS_LPSRTCLR);
+ } while (count1 != count2);
+
+ /* Now wait until counter value changes */
+ do {
+ do {
+ count2 = __raw_readl(ioaddr + SNVS_LPSRTCLR);
+ count3 = __raw_readl(ioaddr + SNVS_LPSRTCLR);
+ } while (count2 != count3);
+ } while (count3 == count1);
+ }
+}
+
+/*!
+ * This function updates the RTC alarm registers and then clears all the
+ * interrupt status bits.
+ *
+ * @param alrm the new alarm value to be updated in the RTC
+ *
+ * @return 0 if successful; non-zero otherwise.
+ */
+static int rtc_update_alarm(struct device *dev, struct rtc_time *alrm)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ void __iomem *ioaddr = pdata->ioaddr;
+ struct rtc_time alarm_tm, now_tm;
+ unsigned long now, time, lp_cr;
+ int ret;
+
+ now = rtc_read_lp_counter(ioaddr + SNVS_LPSRTCMR);
+ rtc_time_to_tm(now, &now_tm);
+
+ alarm_tm.tm_year = now_tm.tm_year;
+ alarm_tm.tm_mon = now_tm.tm_mon;
+ alarm_tm.tm_mday = now_tm.tm_mday;
+
+ alarm_tm.tm_hour = alrm->tm_hour;
+ alarm_tm.tm_min = alrm->tm_min;
+ alarm_tm.tm_sec = alrm->tm_sec;
+
+ rtc_tm_to_time(&now_tm, &now);
+ rtc_tm_to_time(&alarm_tm, &time);
+
+ if (time < now) {
+ time += 60 * 60 * 24;
+ rtc_time_to_tm(time, &alarm_tm);
+ }
+ ret = rtc_tm_to_time(&alarm_tm, &time);
+
+ /* Have to clear LPTA_EN before programming new alarm time in LPTAR */
+ lp_cr = __raw_readl(ioaddr + SNVS_LPCR);
+ __raw_writel(lp_cr & ~SNVS_LPCR_LPTA_EN, ioaddr + SNVS_LPCR);
+ rtc_write_sync_lp(ioaddr);
+
+ __raw_writel(time, ioaddr + SNVS_LPTAR);
+
+ /* clear alarm interrupt status bit */
+ __raw_writel(SNVS_LPSR_LPTA, ioaddr + SNVS_LPSR);
+
+ return ret;
+}
+
+/*!
+ * This function is the RTC interrupt service routine.
+ *
+ * @param irq RTC IRQ number
+ * @param dev_id device ID which is not used
+ *
+ * @return IRQ_HANDLED as defined in the include/linux/interrupt.h file.
+ */
+static irqreturn_t snvs_rtc_interrupt(int irq, void *dev_id)
+{
+ struct platform_device *pdev = dev_id;
+ struct rtc_drv_data *pdata = platform_get_drvdata(pdev);
+ void __iomem *ioaddr = pdata->ioaddr;
+ u32 lp_status, lp_cr;
+ u32 events = 0;
+
+ lp_status = __raw_readl(ioaddr + SNVS_LPSR);
+ lp_cr = __raw_readl(ioaddr + SNVS_LPCR);
+
+ /* update irq data & counter */
+ if (lp_status & SNVS_LPSR_LPTA) {
+ if (lp_cr & SNVS_LPCR_LPTA_EN)
+ events |= (RTC_AF | RTC_IRQF);
+
+ /* disable further lp alarm interrupts */
+ lp_cr &= ~(SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN);
+ }
+
+ /* Update interrupt enables */
+ __raw_writel(lp_cr, ioaddr + SNVS_LPCR);
+
+ /* If no interrupts are enabled, turn off interrupts in kernel */
+ if (((lp_cr & SNVS_LPCR_ALL_INT_EN) == 0) && (pdata->irq_enable)) {
+ disable_irq_nosync(pdata->irq);
+ pdata->irq_enable = false;
+ }
+
+ /* clear interrupt status */
+ __raw_writel(lp_status, ioaddr + SNVS_LPSR);
+
+ rtc_write_sync_lp(ioaddr);
+ rtc_update_irq(pdata->rtc, 1, events);
+ return IRQ_HANDLED;
+}
+
+/*!
+ * This function is used to open the RTC driver.
+ *
+ * @return 0 if successful; non-zero otherwise.
+ */
+static int snvs_rtc_open(struct device *dev)
+{
+ if (test_and_set_bit(1, &rtc_status))
+ return -EBUSY;
+ return 0;
+}
+
+/*!
+ * clear all interrupts and release the IRQ
+ */
+static void snvs_rtc_release(struct device *dev)
+{
+ rtc_status = 0;
+}
+
+/*!
+ * This function reads the current RTC time into tm in Gregorian date.
+ *
+ * @param tm contains the RTC time value upon return
+ *
+ * @return 0 if successful; non-zero otherwise.
+ */
+static int snvs_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ void __iomem *ioaddr = pdata->ioaddr;
+
+ rtc_time_to_tm(rtc_read_lp_counter(ioaddr + SNVS_LPSRTCMR), tm);
+ return 0;
+}
+
+/*!
+ * This function sets the internal RTC time based on tm in Gregorian date.
+ *
+ * @param tm the time value to be set in the RTC
+ *
+ * @return 0 if successful; non-zero otherwise.
+ */
+static int snvs_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ void __iomem *ioaddr = pdata->ioaddr;
+ unsigned long time;
+ int ret;
+ u32 lp_cr;
+
+ ret = rtc_tm_to_time(tm, &time);
+ if (ret != 0)
+ return ret;
+
+ /* Disable RTC first */
+ lp_cr = __raw_readl(ioaddr + SNVS_LPCR) & ~SNVS_LPCR_SRTC_ENV;
+ __raw_writel(lp_cr, ioaddr + SNVS_LPCR);
+ while (__raw_readl(ioaddr + SNVS_LPCR) & SNVS_LPCR_SRTC_ENV)
+ ;
+
+ /* Write 32-bit time to 47-bit timer, leaving 15 LSBs blank */
+ __raw_writel(time << CNTR_TO_SECS_SH, ioaddr + SNVS_LPSRTCLR);
+ __raw_writel(time >> (32 - CNTR_TO_SECS_SH), ioaddr + SNVS_LPSRTCMR);
+
+ /* Enable RTC again */
+ __raw_writel(lp_cr | SNVS_LPCR_SRTC_ENV, ioaddr + SNVS_LPCR);
+ while (!(__raw_readl(ioaddr + SNVS_LPCR) & SNVS_LPCR_SRTC_ENV))
+ ;
+
+ return 0;
+}
+
+/*!
+ * This function reads the current alarm value into the passed in \b alrm
+ * argument. It updates the \b alrm's pending field value based on the whether
+ * an alarm interrupt occurs or not.
+ *
+ * @param alrm contains the RTC alarm value upon return
+ *
+ * @return 0 if successful; non-zero otherwise.
+ */
+static int snvs_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ void __iomem *ioaddr = pdata->ioaddr;
+
+ rtc_time_to_tm(__raw_readl(ioaddr + SNVS_LPTAR), &alrm->time);
+ alrm->pending =
+ ((__raw_readl(ioaddr + SNVS_LPSR) & SNVS_LPSR_LPTA) != 0) ? 1 : 0;
+
+ return 0;
+}
+
+/*!
+ * This function sets the RTC alarm based on passed in alrm.
+ *
+ * @param alrm the alarm value to be set in the RTC
+ *
+ * @return 0 if successful; non-zero otherwise.
+ */
+static int snvs_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ void __iomem *ioaddr = pdata->ioaddr;
+ unsigned long lock_flags = 0;
+ u32 lp_cr;
+ int ret;
+
+ if (rtc_valid_tm(&alrm->time)) {
+ if (alrm->time.tm_sec > 59 ||
+ alrm->time.tm_hour > 23 || alrm->time.tm_min > 59) {
+ return -EINVAL;
+ }
+ }
+
+ spin_lock_irqsave(&rtc_lock, lock_flags);
+
+ ret = rtc_update_alarm(dev, &alrm->time);
+ if (ret)
+ goto out;
+
+ lp_cr = __raw_readl(ioaddr + SNVS_LPCR);
+
+ if (alrm->enabled)
+ lp_cr |= (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN);
+ else
+ lp_cr &= ~(SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN);
+
+ if (lp_cr & SNVS_LPCR_ALL_INT_EN) {
+ if (!pdata->irq_enable) {
+ enable_irq(pdata->irq);
+ pdata->irq_enable = true;
+ }
+ } else {
+ if (pdata->irq_enable) {
+ disable_irq(pdata->irq);
+ pdata->irq_enable = false;
+ }
+ }
+
+ __raw_writel(lp_cr, ioaddr + SNVS_LPCR);
+
+out:
+ rtc_write_sync_lp(ioaddr);
+ spin_unlock_irqrestore(&rtc_lock, lock_flags);
+ return ret;
+}
+
+/*!
+ * This function is used to provide the content for the /proc/driver/rtc
+ * file.
+ *
+ * @param seq buffer to hold the information that the driver wants to write
+ *
+ * @return The number of bytes written into the rtc file.
+ */
+static int snvs_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ void __iomem *ioaddr = pdata->ioaddr;
+
+ seq_printf(seq, "alarm_IRQ\t: %s\n",
+ (((__raw_readl(ioaddr + SNVS_LPCR)) & SNVS_LPCR_LPTA_EN) !=
+ 0) ? "yes" : "no");
+
+ return 0;
+}
+
+static int snvs_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ void __iomem *ioaddr = pdata->ioaddr;
+ u32 lp_cr;
+ unsigned long lock_flags = 0;
+
+ spin_lock_irqsave(&rtc_lock, lock_flags);
+
+ if (enable) {
+ if (!pdata->irq_enable) {
+ enable_irq(pdata->irq);
+ pdata->irq_enable = true;
+ }
+ lp_cr = __raw_readl(ioaddr + SNVS_LPCR);
+ lp_cr |= (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN);
+ __raw_writel(lp_cr, ioaddr + SNVS_LPCR);
+ } else {
+ lp_cr = __raw_readl(ioaddr + SNVS_LPCR);
+ lp_cr &= ~(SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN);
+ if (((lp_cr & SNVS_LPCR_ALL_INT_EN) == 0)
+ && (pdata->irq_enable)) {
+ disable_irq(pdata->irq);
+ pdata->irq_enable = false;
+ }
+ __raw_writel(lp_cr, ioaddr + SNVS_LPCR);
+ }
+
+ rtc_write_sync_lp(ioaddr);
+ spin_unlock_irqrestore(&rtc_lock, lock_flags);
+ return 0;
+}
+
+/*!
+ * The RTC driver structure
+ */
+static struct rtc_class_ops snvs_rtc_ops = {
+ .open = snvs_rtc_open,
+ .release = snvs_rtc_release,
+ .read_time = snvs_rtc_read_time,
+ .set_time = snvs_rtc_set_time,
+ .read_alarm = snvs_rtc_read_alarm,
+ .set_alarm = snvs_rtc_set_alarm,
+ .proc = snvs_rtc_proc,
+ .alarm_irq_enable = snvs_rtc_alarm_irq_enable,
+};
+
+/*! SNVS RTC Power management control */
+static int snvs_rtc_probe(struct platform_device *pdev)
+{
+ struct timespec tv;
+ struct resource *res;
+ struct rtc_device *rtc;
+ struct rtc_drv_data *pdata = NULL;
+ void __iomem *ioaddr;
+ u32 lp_cr;
+ int ret = 0;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+
+ pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return -ENOMEM;
+
+ pdata->baseaddr = res->start;
+ pdata->ioaddr = ioremap(pdata->baseaddr, 0xC00);
+ ioaddr = pdata->ioaddr;
+
+ /* Configure and enable the RTC */
+ pdata->irq = platform_get_irq(pdev, 0);
+ if (pdata->irq >= 0) {
+ if (request_irq(pdata->irq, snvs_rtc_interrupt, IRQF_SHARED,
+ pdev->name, pdev) < 0) {
+ dev_warn(&pdev->dev, "interrupt not available.\n");
+ pdata->irq = -1;
+ } else {
+ disable_irq(pdata->irq);
+ pdata->irq_enable = false;
+ }
+ }
+
+ /* initialize glitch detect */
+ __raw_writel(SNVS_LPPGDR_INIT, ioaddr + SNVS_LPPGDR);
+ udelay(100);
+
+ /* clear lp interrupt status */
+ __raw_writel(0xFFFFFFFF, ioaddr + SNVS_LPSR);
+
+ /* Enable RTC */
+ lp_cr = __raw_readl(ioaddr + SNVS_LPCR);
+ if ((lp_cr & SNVS_LPCR_SRTC_ENV) == 0)
+ __raw_writel(lp_cr | SNVS_LPCR_SRTC_ENV, ioaddr + SNVS_LPCR);
+
+ udelay(100);
+
+ __raw_writel(0xFFFFFFFF, ioaddr + SNVS_LPSR);
+ udelay(100);
+
+ rtc = rtc_device_register(pdev->name, &pdev->dev,
+ &snvs_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc)) {
+ ret = PTR_ERR(rtc);
+ goto err_out;
+ }
+
+ pdata->rtc = rtc;
+ platform_set_drvdata(pdev, pdata);
+
+ tv.tv_nsec = 0;
+ tv.tv_sec = rtc_read_lp_counter(ioaddr + SNVS_LPSRTCMR);
+
+ /* By default, devices should wakeup if they can */
+ /* So snvs is set as "should wakeup" as it can */
+ device_init_wakeup(&pdev->dev, 1);
+
+ return ret;
+
+err_out:
+ iounmap(ioaddr);
+ if (pdata->irq >= 0)
+ free_irq(pdata->irq, pdev);
+ kfree(pdata);
+ return ret;
+}
+
+static int __exit snvs_rtc_remove(struct platform_device *pdev)
+{
+ struct rtc_drv_data *pdata = platform_get_drvdata(pdev);
+ rtc_device_unregister(pdata->rtc);
+ if (pdata->irq >= 0)
+ free_irq(pdata->irq, pdev);
+
+ kfree(pdata);
+ return 0;
+}
+
+/*!
+ * This function is called to save the system time delta relative to
+ * the SNVS RTC when enterring a low power state. This time delta is
+ * then used on resume to adjust the system time to account for time
+ * loss while suspended.
+ *
+ * @param pdev not used
+ * @param state Power state to enter.
+ *
+ * @return The function always returns 0.
+ */
+static int snvs_rtc_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ struct rtc_drv_data *pdata = platform_get_drvdata(pdev);
+
+ if (device_may_wakeup(&pdev->dev)) {
+ enable_irq_wake(pdata->irq);
+ } else {
+ if (pdata->irq_enable)
+ disable_irq(pdata->irq);
+ }
+
+ return 0;
+}
+
+/*!
+ * This function is called to correct the system time based on the
+ * current SNVS RTC time relative to the time delta saved during
+ * suspend.
+ *
+ * @param pdev not used
+ *
+ * @return The function always returns 0.
+ */
+static int snvs_rtc_resume(struct platform_device *pdev)
+{
+ struct rtc_drv_data *pdata = platform_get_drvdata(pdev);
+
+ if (device_may_wakeup(&pdev->dev)) {
+ disable_irq_wake(pdata->irq);
+ } else {
+ if (pdata->irq_enable)
+ enable_irq(pdata->irq);
+ }
+
+ return 0;
+}
+
+/*!
+ * Contains pointers to the power management callback functions.
+ */
+static struct platform_driver snvs_rtc_driver = {
+ .driver = {
+ .name = "snvs_rtc",
+ },
+ .probe = snvs_rtc_probe,
+ .remove = __exit_p(snvs_rtc_remove),
+ .suspend = snvs_rtc_suspend,
+ .resume = snvs_rtc_resume,
+};
+
+/*!
+ * This function creates the /proc/driver/rtc file and registers the device RTC
+ * in the /dev/misc directory. It also reads the RTC value from external source
+ * and setup the internal RTC properly.
+ *
+ * @return -1 if RTC is failed to initialize; 0 is successful.
+ */
+static int __init snvs_rtc_init(void)
+{
+ return platform_driver_register(&snvs_rtc_driver);
+}
+
+/*!
+ * This function removes the /proc/driver/rtc file and un-registers the
+ * device RTC from the /dev/misc directory.
+ */
+static void __exit snvs_rtc_exit(void)
+{
+ platform_driver_unregister(&snvs_rtc_driver);
+
+}
+
+module_init(snvs_rtc_init);
+module_exit(snvs_rtc_exit);
+
+MODULE_AUTHOR("Freescale Semiconductor, Inc.");
+MODULE_DESCRIPTION("SNVS Realtime Clock Driver (RTC)");
+MODULE_LICENSE("GPL");
projects / karo-tx-linux.git / commitdiff