From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- drivers/rtc/rtc-pl031.c | 470 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 470 insertions(+) create mode 100644 drivers/rtc/rtc-pl031.c (limited to 'drivers/rtc/rtc-pl031.c') diff --git a/drivers/rtc/rtc-pl031.c b/drivers/rtc/rtc-pl031.c new file mode 100644 index 000000000..eab39dfa4 --- /dev/null +++ b/drivers/rtc/rtc-pl031.c @@ -0,0 +1,470 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * drivers/rtc/rtc-pl031.c + * + * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC + * + * Author: Deepak Saxena + * + * Copyright 2006 (c) MontaVista Software, Inc. + * + * Author: Mian Yousaf Kaukab + * Copyright 2010 (c) ST-Ericsson AB + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * Register definitions + */ +#define RTC_DR 0x00 /* Data read register */ +#define RTC_MR 0x04 /* Match register */ +#define RTC_LR 0x08 /* Data load register */ +#define RTC_CR 0x0c /* Control register */ +#define RTC_IMSC 0x10 /* Interrupt mask and set register */ +#define RTC_RIS 0x14 /* Raw interrupt status register */ +#define RTC_MIS 0x18 /* Masked interrupt status register */ +#define RTC_ICR 0x1c /* Interrupt clear register */ +/* ST variants have additional timer functionality */ +#define RTC_TDR 0x20 /* Timer data read register */ +#define RTC_TLR 0x24 /* Timer data load register */ +#define RTC_TCR 0x28 /* Timer control register */ +#define RTC_YDR 0x30 /* Year data read register */ +#define RTC_YMR 0x34 /* Year match register */ +#define RTC_YLR 0x38 /* Year data load register */ + +#define RTC_CR_EN (1 << 0) /* counter enable bit */ +#define RTC_CR_CWEN (1 << 26) /* Clockwatch enable bit */ + +#define RTC_TCR_EN (1 << 1) /* Periodic timer enable bit */ + +/* Common bit definitions for Interrupt status and control registers */ +#define RTC_BIT_AI (1 << 0) /* Alarm interrupt bit */ +#define RTC_BIT_PI (1 << 1) /* Periodic interrupt bit. ST variants only. */ + +/* Common bit definations for ST v2 for reading/writing time */ +#define RTC_SEC_SHIFT 0 +#define RTC_SEC_MASK (0x3F << RTC_SEC_SHIFT) /* Second [0-59] */ +#define RTC_MIN_SHIFT 6 +#define RTC_MIN_MASK (0x3F << RTC_MIN_SHIFT) /* Minute [0-59] */ +#define RTC_HOUR_SHIFT 12 +#define RTC_HOUR_MASK (0x1F << RTC_HOUR_SHIFT) /* Hour [0-23] */ +#define RTC_WDAY_SHIFT 17 +#define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */ +#define RTC_MDAY_SHIFT 20 +#define RTC_MDAY_MASK (0x1F << RTC_MDAY_SHIFT) /* Day of Month [1-31] */ +#define RTC_MON_SHIFT 25 +#define RTC_MON_MASK (0xF << RTC_MON_SHIFT) /* Month [1-12] 1=January */ + +#define RTC_TIMER_FREQ 32768 + +/** + * struct pl031_vendor_data - per-vendor variations + * @ops: the vendor-specific operations used on this silicon version + * @clockwatch: if this is an ST Microelectronics silicon version with a + * clockwatch function + * @st_weekday: if this is an ST Microelectronics silicon version that need + * the weekday fix + * @irqflags: special IRQ flags per variant + * @range_min: minimum date/time supported by the RTC + * @range_max: maximum date/time supported by the RTC + */ +struct pl031_vendor_data { + struct rtc_class_ops ops; + bool clockwatch; + bool st_weekday; + unsigned long irqflags; + time64_t range_min; + timeu64_t range_max; +}; + +struct pl031_local { + struct pl031_vendor_data *vendor; + struct rtc_device *rtc; + void __iomem *base; +}; + +static int pl031_alarm_irq_enable(struct device *dev, + unsigned int enabled) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + unsigned long imsc; + + /* Clear any pending alarm interrupts. */ + writel(RTC_BIT_AI, ldata->base + RTC_ICR); + + imsc = readl(ldata->base + RTC_IMSC); + + if (enabled == 1) + writel(imsc | RTC_BIT_AI, ldata->base + RTC_IMSC); + else + writel(imsc & ~RTC_BIT_AI, ldata->base + RTC_IMSC); + + return 0; +} + +/* + * Convert Gregorian date to ST v2 RTC format. + */ +static int pl031_stv2_tm_to_time(struct device *dev, + struct rtc_time *tm, unsigned long *st_time, + unsigned long *bcd_year) +{ + int year = tm->tm_year + 1900; + int wday = tm->tm_wday; + + /* wday masking is not working in hardware so wday must be valid */ + if (wday < -1 || wday > 6) { + dev_err(dev, "invalid wday value %d\n", tm->tm_wday); + return -EINVAL; + } else if (wday == -1) { + /* wday is not provided, calculate it here */ + struct rtc_time calc_tm; + + rtc_time64_to_tm(rtc_tm_to_time64(tm), &calc_tm); + wday = calc_tm.tm_wday; + } + + *bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8); + + *st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT) + | (tm->tm_mday << RTC_MDAY_SHIFT) + | ((wday + 1) << RTC_WDAY_SHIFT) + | (tm->tm_hour << RTC_HOUR_SHIFT) + | (tm->tm_min << RTC_MIN_SHIFT) + | (tm->tm_sec << RTC_SEC_SHIFT); + + return 0; +} + +/* + * Convert ST v2 RTC format to Gregorian date. + */ +static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year, + struct rtc_time *tm) +{ + tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100); + tm->tm_mon = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1; + tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT); + tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1; + tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT); + tm->tm_min = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT); + tm->tm_sec = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT); + + tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); + tm->tm_year -= 1900; + + return 0; +} + +static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + + pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR), + readl(ldata->base + RTC_YDR), tm); + + return 0; +} + +static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm) +{ + unsigned long time; + unsigned long bcd_year; + struct pl031_local *ldata = dev_get_drvdata(dev); + int ret; + + ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year); + if (ret == 0) { + writel(bcd_year, ldata->base + RTC_YLR); + writel(time, ldata->base + RTC_LR); + } + + return ret; +} + +static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + int ret; + + ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR), + readl(ldata->base + RTC_YMR), &alarm->time); + + alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI; + alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI; + + return ret; +} + +static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + unsigned long time; + unsigned long bcd_year; + int ret; + + ret = pl031_stv2_tm_to_time(dev, &alarm->time, + &time, &bcd_year); + if (ret == 0) { + writel(bcd_year, ldata->base + RTC_YMR); + writel(time, ldata->base + RTC_MR); + + pl031_alarm_irq_enable(dev, alarm->enabled); + } + + return ret; +} + +static irqreturn_t pl031_interrupt(int irq, void *dev_id) +{ + struct pl031_local *ldata = dev_id; + unsigned long rtcmis; + unsigned long events = 0; + + rtcmis = readl(ldata->base + RTC_MIS); + if (rtcmis & RTC_BIT_AI) { + writel(RTC_BIT_AI, ldata->base + RTC_ICR); + events |= (RTC_AF | RTC_IRQF); + rtc_update_irq(ldata->rtc, 1, events); + + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static int pl031_read_time(struct device *dev, struct rtc_time *tm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + + rtc_time64_to_tm(readl(ldata->base + RTC_DR), tm); + + return 0; +} + +static int pl031_set_time(struct device *dev, struct rtc_time *tm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + + writel(rtc_tm_to_time64(tm), ldata->base + RTC_LR); + + return 0; +} + +static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + + rtc_time64_to_tm(readl(ldata->base + RTC_MR), &alarm->time); + + alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI; + alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI; + + return 0; +} + +static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + + writel(rtc_tm_to_time64(&alarm->time), ldata->base + RTC_MR); + pl031_alarm_irq_enable(dev, alarm->enabled); + + return 0; +} + +static void pl031_remove(struct amba_device *adev) +{ + struct pl031_local *ldata = dev_get_drvdata(&adev->dev); + + if (adev->irq[0]) + free_irq(adev->irq[0], ldata); + amba_release_regions(adev); +} + +static int pl031_probe(struct amba_device *adev, const struct amba_id *id) +{ + int ret; + struct pl031_local *ldata; + struct pl031_vendor_data *vendor = id->data; + struct rtc_class_ops *ops; + unsigned long time, data; + + ret = amba_request_regions(adev, NULL); + if (ret) + goto err_req; + + ldata = devm_kzalloc(&adev->dev, sizeof(struct pl031_local), + GFP_KERNEL); + ops = devm_kmemdup(&adev->dev, &vendor->ops, sizeof(vendor->ops), + GFP_KERNEL); + if (!ldata || !ops) { + ret = -ENOMEM; + goto out; + } + + ldata->vendor = vendor; + ldata->base = devm_ioremap(&adev->dev, adev->res.start, + resource_size(&adev->res)); + if (!ldata->base) { + ret = -ENOMEM; + goto out; + } + + amba_set_drvdata(adev, ldata); + + dev_dbg(&adev->dev, "designer ID = 0x%02x\n", amba_manf(adev)); + dev_dbg(&adev->dev, "revision = 0x%01x\n", amba_rev(adev)); + + data = readl(ldata->base + RTC_CR); + /* Enable the clockwatch on ST Variants */ + if (vendor->clockwatch) + data |= RTC_CR_CWEN; + else + data |= RTC_CR_EN; + writel(data, ldata->base + RTC_CR); + + /* + * On ST PL031 variants, the RTC reset value does not provide correct + * weekday for 2000-01-01. Correct the erroneous sunday to saturday. + */ + if (vendor->st_weekday) { + if (readl(ldata->base + RTC_YDR) == 0x2000) { + time = readl(ldata->base + RTC_DR); + if ((time & + (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK)) + == 0x02120000) { + time = time | (0x7 << RTC_WDAY_SHIFT); + writel(0x2000, ldata->base + RTC_YLR); + writel(time, ldata->base + RTC_LR); + } + } + } + + devm_device_init_wakeup(&adev->dev); + ldata->rtc = devm_rtc_allocate_device(&adev->dev); + if (IS_ERR(ldata->rtc)) { + ret = PTR_ERR(ldata->rtc); + goto out; + } + + if (!adev->irq[0]) + clear_bit(RTC_FEATURE_ALARM, ldata->rtc->features); + + ldata->rtc->ops = ops; + ldata->rtc->range_min = vendor->range_min; + ldata->rtc->range_max = vendor->range_max; + + ret = devm_rtc_register_device(ldata->rtc); + if (ret) + goto out; + + if (adev->irq[0]) { + ret = request_irq(adev->irq[0], pl031_interrupt, + vendor->irqflags, "rtc-pl031", ldata); + if (ret) + goto out; + devm_pm_set_wake_irq(&adev->dev, adev->irq[0]); + } + return 0; + +out: + amba_release_regions(adev); +err_req: + + return ret; +} + +/* Operations for the original ARM version */ +static struct pl031_vendor_data arm_pl031 = { + .ops = { + .read_time = pl031_read_time, + .set_time = pl031_set_time, + .read_alarm = pl031_read_alarm, + .set_alarm = pl031_set_alarm, + .alarm_irq_enable = pl031_alarm_irq_enable, + }, + .range_max = U32_MAX, +}; + +/* The First ST derivative */ +static struct pl031_vendor_data stv1_pl031 = { + .ops = { + .read_time = pl031_read_time, + .set_time = pl031_set_time, + .read_alarm = pl031_read_alarm, + .set_alarm = pl031_set_alarm, + .alarm_irq_enable = pl031_alarm_irq_enable, + }, + .clockwatch = true, + .st_weekday = true, + .range_max = U32_MAX, +}; + +/* And the second ST derivative */ +static struct pl031_vendor_data stv2_pl031 = { + .ops = { + .read_time = pl031_stv2_read_time, + .set_time = pl031_stv2_set_time, + .read_alarm = pl031_stv2_read_alarm, + .set_alarm = pl031_stv2_set_alarm, + .alarm_irq_enable = pl031_alarm_irq_enable, + }, + .clockwatch = true, + .st_weekday = true, + /* + * This variant shares the IRQ with another block and must not + * suspend that IRQ line. + * TODO check if it shares with IRQF_NO_SUSPEND user, else we can + * remove IRQF_COND_SUSPEND + */ + .irqflags = IRQF_SHARED | IRQF_COND_SUSPEND, + .range_min = RTC_TIMESTAMP_BEGIN_0000, + .range_max = RTC_TIMESTAMP_END_9999, +}; + +static const struct amba_id pl031_ids[] = { + { + .id = 0x00041031, + .mask = 0x000fffff, + .data = &arm_pl031, + }, + /* ST Micro variants */ + { + .id = 0x00180031, + .mask = 0x00ffffff, + .data = &stv1_pl031, + }, + { + .id = 0x00280031, + .mask = 0x00ffffff, + .data = &stv2_pl031, + }, + {0, 0}, +}; + +MODULE_DEVICE_TABLE(amba, pl031_ids); + +static struct amba_driver pl031_driver = { + .drv = { + .name = "rtc-pl031", + }, + .id_table = pl031_ids, + .probe = pl031_probe, + .remove = pl031_remove, +}; + +module_amba_driver(pl031_driver); + +MODULE_AUTHOR("Deepak Saxena "); +MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1