On Fri, Jun 2, 2023 at 5:51 PM Binbin Zhou <zhoubinbin@xxxxxxxxxxx> wrote:
>
> The Loongson family chips use an on-chip counter 0 (Time Of Year
> counter) as the RTC. We will refer to them as rtc-loongson.
>
> Cc: Keguang Zhang <keguang.zhang@xxxxxxxxx>
> Cc: Yang Ling <gnaygnil@xxxxxxxxx>
> Cc: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
> Signed-off-by: Binbin Zhou <zhoubinbin@xxxxxxxxxxx>
> Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxx>
> Signed-off-by: WANG Xuerui <git@xxxxxxxxxx>
Reviewed-by: Keguang Zhang <keguang.zhang@xxxxxxxxx>
Tested-by: Keguang Zhang <keguang.zhang@xxxxxxxxx>
> ---
> drivers/rtc/Kconfig | 13 ++
> drivers/rtc/Makefile | 1 +
> drivers/rtc/rtc-loongson.c | 397 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 411 insertions(+)
> create mode 100644 drivers/rtc/rtc-loongson.c
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 599f5110a251..9f5b0afdbad0 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -1685,6 +1685,19 @@ config RTC_DRV_JZ4740
> This driver can also be built as a module. If so, the module
> will be called rtc-jz4740.
>
> +config RTC_DRV_LOONGSON
> + tristate "Loongson On-chip RTC"
> + depends on MACH_LOONGSON32 || MACH_LOONGSON64 || COMPILE_TEST
> + select REGMAP_MMIO
> + help
> + This is a driver for the Loongson on-chip Counter0 (Time-Of-Year
> + counter) to be used as a RTC.
> + It can be found on Loongson-1 series cpu, Loongson-2K series cpu
> + and Loongson LS7A bridge chips.
> +
> + This driver can also be built as a module. If so, the module
> + will be called rtc-loongson.
> +
> config RTC_DRV_LPC24XX
> tristate "NXP RTC for LPC178x/18xx/408x/43xx"
> depends on ARCH_LPC18XX || COMPILE_TEST
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index c50afd8fb9f4..fd209883ee2e 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -78,6 +78,7 @@ obj-$(CONFIG_RTC_DRV_ISL12022) += rtc-isl12022.o
> obj-$(CONFIG_RTC_DRV_ISL12026) += rtc-isl12026.o
> obj-$(CONFIG_RTC_DRV_ISL1208) += rtc-isl1208.o
> obj-$(CONFIG_RTC_DRV_JZ4740) += rtc-jz4740.o
> +obj-$(CONFIG_RTC_DRV_LOONGSON) += rtc-loongson.o
> obj-$(CONFIG_RTC_DRV_LP8788) += rtc-lp8788.o
> obj-$(CONFIG_RTC_DRV_LPC24XX) += rtc-lpc24xx.o
> obj-$(CONFIG_RTC_DRV_LPC32XX) += rtc-lpc32xx.o
> diff --git a/drivers/rtc/rtc-loongson.c b/drivers/rtc/rtc-loongson.c
> new file mode 100644
> index 000000000000..e8ffc1ab90b0
> --- /dev/null
> +++ b/drivers/rtc/rtc-loongson.c
> @@ -0,0 +1,397 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Loongson RTC driver
> + *
> + * Maintained out-of-tree by Huacai Chen <chenhuacai@xxxxxxxxxx>.
> + * Rewritten for mainline by WANG Xuerui <git@xxxxxxxxxx>.
> + * Binbin Zhou <zhoubinbin@xxxxxxxxxxx>
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/rtc.h>
> +#include <linux/acpi.h>
> +
> +/* Time Of Year(TOY) counters registers */
> +#define TOY_TRIM_REG 0x20 /* Must be initialized to 0 */
> +#define TOY_WRITE0_REG 0x24 /* TOY low 32-bits value (write-only) */
> +#define TOY_WRITE1_REG 0x28 /* TOY high 32-bits value (write-only) */
> +#define TOY_READ0_REG 0x2c /* TOY low 32-bits value (read-only) */
> +#define TOY_READ1_REG 0x30 /* TOY high 32-bits value (read-only) */
> +#define TOY_MATCH0_REG 0x34 /* TOY timing interrupt 0 */
> +#define TOY_MATCH1_REG 0x38 /* TOY timing interrupt 1 */
> +#define TOY_MATCH2_REG 0x3c /* TOY timing interrupt 2 */
> +
> +/* RTC counters registers */
> +#define RTC_CTRL_REG 0x40 /* TOY and RTC control register */
> +#define RTC_TRIM_REG 0x60 /* Must be initialized to 0 */
> +#define RTC_WRITE0_REG 0x64 /* RTC counters value (write-only) */
> +#define RTC_READ0_REG 0x68 /* RTC counters value (read-only) */
> +#define RTC_MATCH0_REG 0x6c /* RTC timing interrupt 0 */
> +#define RTC_MATCH1_REG 0x70 /* RTC timing interrupt 1 */
> +#define RTC_MATCH2_REG 0x74 /* RTC timing interrupt 2 */
> +
> +/* bitmask of TOY_WRITE0_REG */
> +#define TOY_MON GENMASK(31, 26)
> +#define TOY_DAY GENMASK(25, 21)
> +#define TOY_HOUR GENMASK(20, 16)
> +#define TOY_MIN GENMASK(15, 10)
> +#define TOY_SEC GENMASK(9, 4)
> +#define TOY_MSEC GENMASK(3, 0)
> +
> +/* bitmask of TOY_MATCH0/1/2_REG */
> +#define TOY_MATCH_YEAR GENMASK(31, 26)
> +#define TOY_MATCH_MON GENMASK(25, 22)
> +#define TOY_MATCH_DAY GENMASK(21, 17)
> +#define TOY_MATCH_HOUR GENMASK(16, 12)
> +#define TOY_MATCH_MIN GENMASK(11, 6)
> +#define TOY_MATCH_SEC GENMASK(5, 0)
> +
> +/* bitmask of RTC_CTRL_REG */
> +#define RTC_ENABLE BIT(13) /* 1: RTC counters enable */
> +#define TOY_ENABLE BIT(11) /* 1: TOY counters enable */
> +#define OSC_ENABLE BIT(8) /* 1: 32.768k crystal enable */
> +#define TOY_ENABLE_MASK (TOY_ENABLE | OSC_ENABLE)
> +
> +/* PM domain registers */
> +#define PM1_STS_REG 0x0c /* Power management 1 status register */
> +#define RTC_STS BIT(10) /* RTC status */
> +#define PM1_EN_REG 0x10 /* Power management 1 enable register */
> +#define RTC_EN BIT(10) /* RTC event enable */
> +
> +/*
> + * According to the LS1C manual, RTC_CTRL and alarm-related registers are not defined.
> + * Accessing the relevant registers will cause the system to hang.
> + */
> +#define LS1C_RTC_CTRL_WORKAROUND BIT(0)
> +
> +struct loongson_rtc_config {
> + u32 pm_offset; /* Offset of PM domain, for RTC alarm wakeup */
> + u32 flags; /* Workaround bits */
> +};
> +
> +struct loongson_rtc_priv {
> + spinlock_t lock; /* protects PM registers access */
> + u32 fix_year; /* RTC alarm year compensation value */
> + struct rtc_device *rtcdev;
> + struct regmap *regmap;
> + void __iomem *pm_base; /* PM domain base, for RTC alarm wakeup */
> + const struct loongson_rtc_config *config;
> +};
> +
> +static const struct loongson_rtc_config ls1b_rtc_config = {
> + .pm_offset = 0,
> + .flags = 0,
> +};
> +
> +static const struct loongson_rtc_config ls1c_rtc_config = {
> + .pm_offset = 0,
> + .flags = LS1C_RTC_CTRL_WORKAROUND,
> +};
> +
> +static const struct loongson_rtc_config generic_rtc_config = {
> + .pm_offset = 0x100,
> + .flags = 0,
> +};
> +
> +static const struct loongson_rtc_config ls2k1000_rtc_config = {
> + .pm_offset = 0x800,
> + .flags = 0,
> +};
> +
> +static const struct regmap_config loongson_rtc_regmap_config = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4,
> +};
> +
> +/* RTC alarm irq handler */
> +static irqreturn_t loongson_rtc_isr(int irq, void *id)
> +{
> + struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
> +
> + rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
> + return IRQ_HANDLED;
> +}
> +
> +/* For ACPI fixed event handler */
> +static u32 loongson_rtc_handler(void *id)
> +{
> + struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
> +
> + spin_lock(&priv->lock);
> + /* Disable RTC alarm wakeup and interrupt */
> + writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
> + priv->pm_base + PM1_EN_REG);
> +
> + /* Clear RTC interrupt status */
> + writel(RTC_STS, priv->pm_base + PM1_STS_REG);
> + spin_unlock(&priv->lock);
> +
> + /*
> + * The TOY_MATCH0_REG should be cleared 0 here,
> + * otherwise the interrupt cannot be cleared.
> + */
> + return regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
> +}
> +
> +static int loongson_rtc_set_enabled(struct device *dev)
> +{
> + struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
> +
> + if (priv->config->flags & LS1C_RTC_CTRL_WORKAROUND)
> + return 0;
> +
> + /* Enable RTC TOY counters and crystal */
> + return regmap_update_bits(priv->regmap, RTC_CTRL_REG, TOY_ENABLE_MASK,
> + TOY_ENABLE_MASK);
> +}
> +
> +static bool loongson_rtc_get_enabled(struct device *dev)
> +{
> + int ret;
> + u32 ctrl_data;
> + struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
> +
> + if (priv->config->flags & LS1C_RTC_CTRL_WORKAROUND)
> + return true;
> +
> + ret = regmap_read(priv->regmap, RTC_CTRL_REG, &ctrl_data);
> + if (ret < 0)
> + return false;
> +
> + return ctrl_data & TOY_ENABLE_MASK;
> +}
> +
> +static int loongson_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> + int ret;
> + u32 rtc_data[2];
> + struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
> +
> + if (!loongson_rtc_get_enabled(dev))
> + return -EINVAL;
> +
> + ret = regmap_bulk_read(priv->regmap, TOY_READ0_REG, rtc_data,
> + ARRAY_SIZE(rtc_data));
> + if (ret < 0)
> + return ret;
> +
> + tm->tm_sec = FIELD_GET(TOY_SEC, rtc_data[0]);
> + tm->tm_min = FIELD_GET(TOY_MIN, rtc_data[0]);
> + tm->tm_hour = FIELD_GET(TOY_HOUR, rtc_data[0]);
> + tm->tm_mday = FIELD_GET(TOY_DAY, rtc_data[0]);
> + tm->tm_mon = FIELD_GET(TOY_MON, rtc_data[0]) - 1;
> + tm->tm_year = rtc_data[1];
> +
> + /* Prepare for RTC alarm year compensation value. */
> + priv->fix_year = tm->tm_year / 64 * 64;
> + return 0;
> +}
> +
> +static int loongson_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> + int ret;
> + u32 rtc_data[2];
> + struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
> +
> + rtc_data[0] = FIELD_PREP(TOY_SEC, tm->tm_sec)
> + | FIELD_PREP(TOY_MIN, tm->tm_min)
> + | FIELD_PREP(TOY_HOUR, tm->tm_hour)
> + | FIELD_PREP(TOY_DAY, tm->tm_mday)
> + | FIELD_PREP(TOY_MON, tm->tm_mon + 1);
> + rtc_data[1] = tm->tm_year;
> +
> + ret = regmap_bulk_write(priv->regmap, TOY_WRITE0_REG, rtc_data,
> + ARRAY_SIZE(rtc_data));
> + if (ret < 0)
> + return ret;
> +
> + return loongson_rtc_set_enabled(dev);
> +}
> +
> +static int loongson_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> + int ret;
> + u32 alarm_data;
> + struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
> +
> + ret = regmap_read(priv->regmap, TOY_MATCH0_REG, &alarm_data);
> + if (ret < 0)
> + return ret;
> +
> + alrm->time.tm_sec = FIELD_GET(TOY_MATCH_SEC, alarm_data);
> + alrm->time.tm_min = FIELD_GET(TOY_MATCH_MIN, alarm_data);
> + alrm->time.tm_hour = FIELD_GET(TOY_MATCH_HOUR, alarm_data);
> + alrm->time.tm_mday = FIELD_GET(TOY_MATCH_DAY, alarm_data);
> + alrm->time.tm_mon = FIELD_GET(TOY_MATCH_MON, alarm_data) - 1;
> + /*
> + * This is a hardware bug: the year field of SYS_TOYMATCH is only 6 bits,
> + * making it impossible to save year values larger than 64.
> + *
> + * SYS_TOYMATCH is used to match the alarm time value and determine if
> + * an alarm is triggered, so we must keep the lower 6 bits of the year
> + * value constant during the value conversion.
> + *
> + * In summary, we need to manually add 64(or a multiple of 64) to the
> + * year value to avoid the invalid alarm prompt at startup.
> + */
> + alrm->time.tm_year = FIELD_GET(TOY_MATCH_YEAR, alarm_data) + priv->fix_year;
> +
> + alrm->enabled = !!(readl(priv->pm_base + PM1_EN_REG) & RTC_EN);
> + return 0;
> +}
> +
> +static int loongson_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
> +{
> + u32 val;
> + struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
> +
> + spin_lock(&priv->lock);
> + val = readl(priv->pm_base + PM1_EN_REG);
> + /* Enable RTC alarm wakeup */
> + writel(enabled ? val | RTC_EN : val & ~RTC_EN,
> + priv->pm_base + PM1_EN_REG);
> + spin_unlock(&priv->lock);
> +
> + return 0;
> +}
> +
> +static int loongson_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> + int ret;
> + u32 alarm_data;
> + struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
> +
> + alarm_data = FIELD_PREP(TOY_MATCH_SEC, alrm->time.tm_sec)
> + | FIELD_PREP(TOY_MATCH_MIN, alrm->time.tm_min)
> + | FIELD_PREP(TOY_MATCH_HOUR, alrm->time.tm_hour)
> + | FIELD_PREP(TOY_MATCH_DAY, alrm->time.tm_mday)
> + | FIELD_PREP(TOY_MATCH_MON, alrm->time.tm_mon + 1)
> + | FIELD_PREP(TOY_MATCH_YEAR, alrm->time.tm_year - priv->fix_year);
> +
> + ret = regmap_write(priv->regmap, TOY_MATCH0_REG, alarm_data);
> + if (ret < 0)
> + return ret;
> +
> + return loongson_rtc_alarm_irq_enable(dev, alrm->enabled);
> +}
> +
> +static const struct rtc_class_ops loongson_rtc_ops = {
> + .read_time = loongson_rtc_read_time,
> + .set_time = loongson_rtc_set_time,
> + .read_alarm = loongson_rtc_read_alarm,
> + .set_alarm = loongson_rtc_set_alarm,
> + .alarm_irq_enable = loongson_rtc_alarm_irq_enable,
> +};
> +
> +static int loongson_rtc_probe(struct platform_device *pdev)
> +{
> + int ret, alarm_irq;
> + void __iomem *regs;
> + struct loongson_rtc_priv *priv;
> + struct device *dev = &pdev->dev;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + regs = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(regs))
> + return dev_err_probe(dev, PTR_ERR(regs),
> + "devm_platform_ioremap_resource failed\n");
> +
> + priv->regmap = devm_regmap_init_mmio(dev, regs,
> + &loongson_rtc_regmap_config);
> + if (IS_ERR(priv->regmap))
> + return dev_err_probe(dev, PTR_ERR(priv->regmap),
> + "devm_regmap_init_mmio failed\n");
> +
> + priv->config = device_get_match_data(dev);
> + spin_lock_init(&priv->lock);
> + platform_set_drvdata(pdev, priv);
> +
> + priv->rtcdev = devm_rtc_allocate_device(dev);
> + if (IS_ERR(priv->rtcdev))
> + return dev_err_probe(dev, PTR_ERR(priv->rtcdev),
> + "devm_rtc_allocate_device failed\n");
> +
> + /* Get RTC alarm irq */
> + alarm_irq = platform_get_irq(pdev, 0);
> + if (alarm_irq > 0) {
> + ret = devm_request_irq(dev, alarm_irq, loongson_rtc_isr,
> + 0, "loongson-alarm", priv);
> + if (ret < 0)
> + return dev_err_probe(dev, ret, "Unable to request irq %d\n",
> + alarm_irq);
> +
> + priv->pm_base = regs - priv->config->pm_offset;
> + device_init_wakeup(dev, 1);
> +
> + if (has_acpi_companion(dev))
> + acpi_install_fixed_event_handler(ACPI_EVENT_RTC,
> + loongson_rtc_handler, priv);
> + } else {
> + /* Loongson-1C RTC does not support alarm */
> + clear_bit(RTC_FEATURE_ALARM, priv->rtcdev->features);
> + }
> +
> + /* Loongson RTC does not support UIE */
> + clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, priv->rtcdev->features);
> + priv->rtcdev->ops = &loongson_rtc_ops;
> + priv->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000;
> + priv->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
> +
> + return devm_rtc_register_device(priv->rtcdev);
> +}
> +
> +static void loongson_rtc_remove(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
> +
> + if (!test_bit(RTC_FEATURE_ALARM, priv->rtcdev->features))
> + return;
> +
> + if (has_acpi_companion(dev))
> + acpi_remove_fixed_event_handler(ACPI_EVENT_RTC,
> + loongson_rtc_handler);
> +
> + device_init_wakeup(dev, 0);
> + loongson_rtc_alarm_irq_enable(dev, 0);
> +}
> +
> +static const struct of_device_id loongson_rtc_of_match[] = {
> + { .compatible = "loongson,ls1b-rtc", .data = &ls1b_rtc_config },
> + { .compatible = "loongson,ls1c-rtc", .data = &ls1c_rtc_config },
> + { .compatible = "loongson,ls7a-rtc", .data = &generic_rtc_config },
> + { .compatible = "loongson,ls2k1000-rtc", .data = &ls2k1000_rtc_config },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, loongson_rtc_of_match);
> +
> +static const struct acpi_device_id loongson_rtc_acpi_match[] = {
> + { "LOON0001", .driver_data = (kernel_ulong_t)&generic_rtc_config },
> + { }
> +};
> +MODULE_DEVICE_TABLE(acpi, loongson_rtc_acpi_match);
> +
> +static struct platform_driver loongson_rtc_driver = {
> + .probe = loongson_rtc_probe,
> + .remove_new = loongson_rtc_remove,
> + .driver = {
> + .name = "loongson-rtc",
> + .of_match_table = loongson_rtc_of_match,
> + .acpi_match_table = loongson_rtc_acpi_match,
> + },
> +};
> +module_platform_driver(loongson_rtc_driver);
> +
> +MODULE_DESCRIPTION("Loongson RTC driver");
> +MODULE_AUTHOR("Binbin Zhou <zhoubinbin@xxxxxxxxxxx>");
> +MODULE_AUTHOR("WANG Xuerui <git@xxxxxxxxxx>");
> +MODULE_AUTHOR("Huacai Chen <chenhuacai@xxxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> --
> 2.39.1
>
--
Best regards,
Keguang Zhang
