Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 446 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c
new file mode 100644
index 000000000..d82acf1af
--- /dev/null
+++ b/drivers/rtc/rtc-snvs.c
@@ -0,0 +1,446 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Copyright (C) 2011-2012 Freescale Semiconductor, Inc.
+
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_wakeirq.h>
+#include <linux/rtc.h>
+#include <linux/clk.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+
+#define SNVS_LPREGISTER_OFFSET	0x34
+
+/* These register offsets are relative to LP (Low Power) range */
+#define SNVS_LPCR		0x04
+#define SNVS_LPSR		0x18
+#define SNVS_LPSRTCMR		0x1c
+#define SNVS_LPSRTCLR		0x20
+#define SNVS_LPTAR		0x24
+#define SNVS_LPPGDR		0x30
+
+#define SNVS_LPCR_SRTC_ENV	(1 << 0)
+#define SNVS_LPCR_LPTA_EN	(1 << 1)
+#define SNVS_LPCR_LPWUI_EN	(1 << 3)
+#define SNVS_LPSR_LPTA		(1 << 0)
+
+#define SNVS_LPPGDR_INIT	0x41736166
+#define CNTR_TO_SECS_SH		15
+
+/* The maximum RTC clock cycles that are allowed to pass between two
+ * consecutive clock counter register reads. If the values are corrupted a
+ * bigger difference is expected. The RTC frequency is 32kHz. With 320 cycles
+ * we end at 10ms which should be enough for most cases. If it once takes
+ * longer than expected we do a retry.
+ */
+#define MAX_RTC_READ_DIFF_CYCLES	320
+
+struct snvs_rtc_data {
+	struct rtc_device *rtc;
+	struct regmap *regmap;
+	int offset;
+	int irq;
+	struct clk *clk;
+};
+
+/* Read 64 bit timer register, which could be in inconsistent state */
+static u64 rtc_read_lpsrt(struct snvs_rtc_data *data)
+{
+	u32 msb, lsb;
+
+	regmap_read(data->regmap, data->offset + SNVS_LPSRTCMR, &msb);
+	regmap_read(data->regmap, data->offset + SNVS_LPSRTCLR, &lsb);
+	return (u64)msb << 32 | lsb;
+}
+
+/* Read the secure real time counter, taking care to deal with the cases of the
+ * counter updating while being read.
+ */
+static u32 rtc_read_lp_counter(struct snvs_rtc_data *data)
+{
+	u64 read1, read2;
+	s64 diff;
+	unsigned int timeout = 100;
+
+	/* As expected, the registers might update between the read of the LSB
+	 * reg and the MSB reg.  It's also possible that one register might be
+	 * in partially modified state as well.
+	 */
+	read1 = rtc_read_lpsrt(data);
+	do {
+		read2 = read1;
+		read1 = rtc_read_lpsrt(data);
+		diff = read1 - read2;
+	} while (((diff < 0) || (diff > MAX_RTC_READ_DIFF_CYCLES)) && --timeout);
+	if (!timeout)
+		dev_err(&data->rtc->dev, "Timeout trying to get valid LPSRT Counter read\n");
+
+	/* Convert 47-bit counter to 32-bit raw second count */
+	return (u32) (read1 >> CNTR_TO_SECS_SH);
+}
+
+/* Just read the lsb from the counter, dealing with inconsistent state */
+static int rtc_read_lp_counter_lsb(struct snvs_rtc_data *data, u32 *lsb)
+{
+	u32 count1, count2;
+	s32 diff;
+	unsigned int timeout = 100;
+
+	regmap_read(data->regmap, data->offset + SNVS_LPSRTCLR, &count1);
+	do {
+		count2 = count1;
+		regmap_read(data->regmap, data->offset + SNVS_LPSRTCLR, &count1);
+		diff = count1 - count2;
+	} while (((diff < 0) || (diff > MAX_RTC_READ_DIFF_CYCLES)) && --timeout);
+	if (!timeout) {
+		dev_err(&data->rtc->dev, "Timeout trying to get valid LPSRT Counter read\n");
+		return -ETIMEDOUT;
+	}
+
+	*lsb = count1;
+	return 0;
+}
+
+static int rtc_write_sync_lp(struct snvs_rtc_data *data)
+{
+	u32 count1, count2;
+	u32 elapsed;
+	unsigned int timeout = 1000;
+	int ret;
+
+	ret = rtc_read_lp_counter_lsb(data, &count1);
+	if (ret)
+		return ret;
+
+	/* Wait for 3 CKIL cycles, about 61.0-91.5 µs */
+	do {
+		ret = rtc_read_lp_counter_lsb(data, &count2);
+		if (ret)
+			return ret;
+		elapsed = count2 - count1; /* wrap around _is_ handled! */
+	} while (elapsed < 3 && --timeout);
+	if (!timeout) {
+		dev_err(&data->rtc->dev, "Timeout waiting for LPSRT Counter to change\n");
+		return -ETIMEDOUT;
+	}
+	return 0;
+}
+
+static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable)
+{
+	int timeout = 1000;
+	u32 lpcr;
+
+	regmap_update_bits(data->regmap, data->offset + SNVS_LPCR, SNVS_LPCR_SRTC_ENV,
+			   enable ? SNVS_LPCR_SRTC_ENV : 0);
+
+	while (--timeout) {
+		regmap_read(data->regmap, data->offset + SNVS_LPCR, &lpcr);
+
+		if (enable) {
+			if (lpcr & SNVS_LPCR_SRTC_ENV)
+				break;
+		} else {
+			if (!(lpcr & SNVS_LPCR_SRTC_ENV))
+				break;
+		}
+	}
+
+	if (!timeout)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static int snvs_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct snvs_rtc_data *data = dev_get_drvdata(dev);
+	unsigned long time;
+	int ret;
+
+	ret = clk_enable(data->clk);
+	if (ret)
+		return ret;
+
+	time = rtc_read_lp_counter(data);
+	rtc_time64_to_tm(time, tm);
+
+	clk_disable(data->clk);
+
+	return 0;
+}
+
+static int snvs_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct snvs_rtc_data *data = dev_get_drvdata(dev);
+	unsigned long time = rtc_tm_to_time64(tm);
+	int ret;
+
+	ret = clk_enable(data->clk);
+	if (ret)
+		return ret;
+
+	/* Disable RTC first */
+	ret = snvs_rtc_enable(data, false);
+	if (ret)
+		return ret;
+
+	/* Write 32-bit time to 47-bit timer, leaving 15 LSBs blank */
+	regmap_write(data->regmap, data->offset + SNVS_LPSRTCLR, time << CNTR_TO_SECS_SH);
+	regmap_write(data->regmap, data->offset + SNVS_LPSRTCMR, time >> (32 - CNTR_TO_SECS_SH));
+
+	/* Enable RTC again */
+	ret = snvs_rtc_enable(data, true);
+
+	clk_disable(data->clk);
+
+	return ret;
+}
+
+static int snvs_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct snvs_rtc_data *data = dev_get_drvdata(dev);
+	u32 lptar, lpsr;
+	int ret;
+
+	ret = clk_enable(data->clk);
+	if (ret)
+		return ret;
+
+	regmap_read(data->regmap, data->offset + SNVS_LPTAR, &lptar);
+	rtc_time64_to_tm(lptar, &alrm->time);
+
+	regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr);
+	alrm->pending = (lpsr & SNVS_LPSR_LPTA) ? 1 : 0;
+
+	clk_disable(data->clk);
+
+	return 0;
+}
+
+static int snvs_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
+{
+	struct snvs_rtc_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_enable(data->clk);
+	if (ret)
+		return ret;
+
+	regmap_update_bits(data->regmap, data->offset + SNVS_LPCR,
+			   (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN),
+			   enable ? (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN) : 0);
+
+	ret = rtc_write_sync_lp(data);
+
+	clk_disable(data->clk);
+
+	return ret;
+}
+
+static int snvs_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct snvs_rtc_data *data = dev_get_drvdata(dev);
+	unsigned long time = rtc_tm_to_time64(&alrm->time);
+	int ret;
+
+	ret = clk_enable(data->clk);
+	if (ret)
+		return ret;
+
+	regmap_update_bits(data->regmap, data->offset + SNVS_LPCR, SNVS_LPCR_LPTA_EN, 0);
+	ret = rtc_write_sync_lp(data);
+	if (ret)
+		return ret;
+	regmap_write(data->regmap, data->offset + SNVS_LPTAR, time);
+
+	/* Clear alarm interrupt status bit */
+	regmap_write(data->regmap, data->offset + SNVS_LPSR, SNVS_LPSR_LPTA);
+
+	clk_disable(data->clk);
+
+	return snvs_rtc_alarm_irq_enable(dev, alrm->enabled);
+}
+
+static const struct rtc_class_ops snvs_rtc_ops = {
+	.read_time = snvs_rtc_read_time,
+	.set_time = snvs_rtc_set_time,
+	.read_alarm = snvs_rtc_read_alarm,
+	.set_alarm = snvs_rtc_set_alarm,
+	.alarm_irq_enable = snvs_rtc_alarm_irq_enable,
+};
+
+static irqreturn_t snvs_rtc_irq_handler(int irq, void *dev_id)
+{
+	struct device *dev = dev_id;
+	struct snvs_rtc_data *data = dev_get_drvdata(dev);
+	u32 lpsr;
+	u32 events = 0;
+
+	clk_enable(data->clk);
+
+	regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr);
+
+	if (lpsr & SNVS_LPSR_LPTA) {
+		events |= (RTC_AF | RTC_IRQF);
+
+		/* RTC alarm should be one-shot */
+		snvs_rtc_alarm_irq_enable(dev, 0);
+
+		rtc_update_irq(data->rtc, 1, events);
+	}
+
+	/* clear interrupt status */
+	regmap_write(data->regmap, data->offset + SNVS_LPSR, lpsr);
+
+	clk_disable(data->clk);
+
+	return events ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static const struct regmap_config snvs_rtc_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};
+
+static void snvs_rtc_action(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
+static int snvs_rtc_probe(struct platform_device *pdev)
+{
+	struct snvs_rtc_data *data;
+	int ret;
+	void __iomem *mmio;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(data->rtc))
+		return PTR_ERR(data->rtc);
+
+	data->regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap");
+
+	if (IS_ERR(data->regmap)) {
+		dev_warn(&pdev->dev, "snvs rtc: you use old dts file, please update it\n");
+
+		mmio = devm_platform_ioremap_resource(pdev, 0);
+		if (IS_ERR(mmio))
+			return PTR_ERR(mmio);
+
+		data->regmap = devm_regmap_init_mmio(&pdev->dev, mmio, &snvs_rtc_config);
+	} else {
+		data->offset = SNVS_LPREGISTER_OFFSET;
+		of_property_read_u32(pdev->dev.of_node, "offset", &data->offset);
+	}
+
+	if (IS_ERR(data->regmap)) {
+		dev_err(&pdev->dev, "Can't find snvs syscon\n");
+		return -ENODEV;
+	}
+
+	data->irq = platform_get_irq(pdev, 0);
+	if (data->irq < 0)
+		return data->irq;
+
+	data->clk = devm_clk_get(&pdev->dev, "snvs-rtc");
+	if (IS_ERR(data->clk)) {
+		data->clk = NULL;
+	} else {
+		ret = clk_prepare_enable(data->clk);
+		if (ret) {
+			dev_err(&pdev->dev,
+				"Could not prepare or enable the snvs clock\n");
+			return ret;
+		}
+	}
+
+	ret = devm_add_action_or_reset(&pdev->dev, snvs_rtc_action, data->clk);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, data);
+
+	/* Initialize glitch detect */
+	regmap_write(data->regmap, data->offset + SNVS_LPPGDR, SNVS_LPPGDR_INIT);
+
+	/* Clear interrupt status */
+	regmap_write(data->regmap, data->offset + SNVS_LPSR, 0xffffffff);
+
+	/* Enable RTC */
+	ret = snvs_rtc_enable(data, true);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to enable rtc %d\n", ret);
+		return ret;
+	}
+
+	device_init_wakeup(&pdev->dev, true);
+	ret = dev_pm_set_wake_irq(&pdev->dev, data->irq);
+	if (ret)
+		dev_err(&pdev->dev, "failed to enable irq wake\n");
+
+	ret = devm_request_irq(&pdev->dev, data->irq, snvs_rtc_irq_handler,
+			       IRQF_SHARED, "rtc alarm", &pdev->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to request irq %d: %d\n",
+			data->irq, ret);
+		return ret;
+	}
+
+	data->rtc->ops = &snvs_rtc_ops;
+	data->rtc->range_max = U32_MAX;
+
+	return devm_rtc_register_device(data->rtc);
+}
+
+static int __maybe_unused snvs_rtc_suspend_noirq(struct device *dev)
+{
+	struct snvs_rtc_data *data = dev_get_drvdata(dev);
+
+	clk_disable(data->clk);
+
+	return 0;
+}
+
+static int __maybe_unused snvs_rtc_resume_noirq(struct device *dev)
+{
+	struct snvs_rtc_data *data = dev_get_drvdata(dev);
+
+	if (data->clk)
+		return clk_enable(data->clk);
+
+	return 0;
+}
+
+static const struct dev_pm_ops snvs_rtc_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(snvs_rtc_suspend_noirq, snvs_rtc_resume_noirq)
+};
+
+static const struct of_device_id snvs_dt_ids[] = {
+	{ .compatible = "fsl,sec-v4.0-mon-rtc-lp", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, snvs_dt_ids);
+
+static struct platform_driver snvs_rtc_driver = {
+	.driver = {
+		.name	= "snvs_rtc",
+		.pm	= &snvs_rtc_pm_ops,
+		.of_match_table = snvs_dt_ids,
+	},
+	.probe		= snvs_rtc_probe,
+};
+module_platform_driver(snvs_rtc_driver);
+
+MODULE_AUTHOR("Freescale Semiconductor, Inc.");
+MODULE_DESCRIPTION("Freescale SNVS RTC Driver");
+MODULE_LICENSE("GPL");