Re: [PATCH v1] rtc: mrst: Remove driver for deprecated platform

[Alexandre Belloni <alexandre.belloni@bootlin.com>]

On 22/01/2021 14:22:26+0200, Andy Shevchenko wrote:
> Intel Moorestown and Medfield are quite old Intel Atom based
> 32-bit platforms, which were in limited use in some Android phones,
> tablets and consumer electronics more than eight years ago.
> 
> There are no bugs or problems ever reported outside from Intel
> for breaking any of that platforms for years. It seems no real
> users exists who run more or less fresh kernel on it. The commit
> 05f4434bc130 ("ASoC: Intel: remove mfld_machine") also in align
> with this theory.
> 
> Due to above and to reduce a burden of supporting outdated drivers
> we remove the support of outdated platforms completely.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

> ---
>  drivers/rtc/Kconfig    |  12 -
>  drivers/rtc/Makefile   |   1 -
>  drivers/rtc/rtc-mrst.c | 521 -----------------------------------------
>  3 files changed, 534 deletions(-)
>  delete mode 100644 drivers/rtc/rtc-mrst.c
> 
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 6123f9f4fbc9..2a402c10f8f1 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -973,18 +973,6 @@ config RTC_DRV_ALPHA
>  	  Direct support for the real-time clock found on every Alpha
>  	  system, specifically MC146818 compatibles.  If in doubt, say Y.
>  
> -config RTC_DRV_VRTC
> -	tristate "Virtual RTC for Intel MID platforms"
> -	depends on X86_INTEL_MID
> -	default y if X86_INTEL_MID
> -
> -	help
> -	Say "yes" here to get direct support for the real time clock
> -	found on Moorestown platforms. The VRTC is a emulated RTC that
> -	derives its clock source from a real RTC in the PMIC. The MC146818
> -	style programming interface is mostly conserved, but any
> -	updates are done via IPC calls to the system controller FW.
> -
>  config RTC_DRV_DS1216
>  	tristate "Dallas DS1216"
>  	depends on SNI_RM
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index bb8f319b09fb..f8ac4f574522 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -174,7 +174,6 @@ obj-$(CONFIG_RTC_DRV_TWL4030)	+= rtc-twl.o
>  obj-$(CONFIG_RTC_DRV_TX4939)	+= rtc-tx4939.o
>  obj-$(CONFIG_RTC_DRV_V3020)	+= rtc-v3020.o
>  obj-$(CONFIG_RTC_DRV_VR41XX)	+= rtc-vr41xx.o
> -obj-$(CONFIG_RTC_DRV_VRTC)	+= rtc-mrst.o
>  obj-$(CONFIG_RTC_DRV_VT8500)	+= rtc-vt8500.o
>  obj-$(CONFIG_RTC_DRV_WILCO_EC)	+= rtc-wilco-ec.o
>  obj-$(CONFIG_RTC_DRV_WM831X)	+= rtc-wm831x.o
> diff --git a/drivers/rtc/rtc-mrst.c b/drivers/rtc/rtc-mrst.c
> deleted file mode 100644
> index 421b3b6071b6..000000000000
> --- a/drivers/rtc/rtc-mrst.c
> +++ /dev/null
> @@ -1,521 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/*
> - * rtc-mrst.c: Driver for Moorestown virtual RTC
> - *
> - * (C) Copyright 2009 Intel Corporation
> - * Author: Jacob Pan (jacob.jun.pan@intel.com)
> - *	   Feng Tang (feng.tang@intel.com)
> - *
> - * Note:
> - * VRTC is emulated by system controller firmware, the real HW
> - * RTC is located in the PMIC device. SCU FW shadows PMIC RTC
> - * in a memory mapped IO space that is visible to the host IA
> - * processor.
> - *
> - * This driver is based upon drivers/rtc/rtc-cmos.c
> - */
> -
> -/*
> - * Note:
> - *  * vRTC only supports binary mode and 24H mode
> - *  * vRTC only support PIE and AIE, no UIE, and its PIE only happens
> - *    at 23:59:59pm everyday, no support for adjustable frequency
> - *  * Alarm function is also limited to hr/min/sec.
> - */
> -
> -#include <linux/mod_devicetable.h>
> -#include <linux/platform_device.h>
> -#include <linux/interrupt.h>
> -#include <linux/spinlock.h>
> -#include <linux/kernel.h>
> -#include <linux/mc146818rtc.h>
> -#include <linux/module.h>
> -#include <linux/init.h>
> -#include <linux/sfi.h>
> -
> -#include <asm/intel_scu_ipc.h>
> -#include <asm/intel-mid.h>
> -#include <asm/intel_mid_vrtc.h>
> -
> -struct mrst_rtc {
> -	struct rtc_device	*rtc;
> -	struct device		*dev;
> -	int			irq;
> -
> -	u8			enabled_wake;
> -	u8			suspend_ctrl;
> -};
> -
> -static const char driver_name[] = "rtc_mrst";
> -
> -#define	RTC_IRQMASK	(RTC_PF | RTC_AF)
> -
> -static inline int is_intr(u8 rtc_intr)
> -{
> -	if (!(rtc_intr & RTC_IRQF))
> -		return 0;
> -	return rtc_intr & RTC_IRQMASK;
> -}
> -
> -static inline unsigned char vrtc_is_updating(void)
> -{
> -	unsigned char uip;
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&rtc_lock, flags);
> -	uip = (vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP);
> -	spin_unlock_irqrestore(&rtc_lock, flags);
> -	return uip;
> -}
> -
> -/*
> - * rtc_time's year contains the increment over 1900, but vRTC's YEAR
> - * register can't be programmed to value larger than 0x64, so vRTC
> - * driver chose to use 1972 (1970 is UNIX time start point) as the base,
> - * and does the translation at read/write time.
> - *
> - * Why not just use 1970 as the offset? it's because using 1972 will
> - * make it consistent in leap year setting for both vrtc and low-level
> - * physical rtc devices. Then why not use 1960 as the offset? If we use
> - * 1960, for a device's first use, its YEAR register is 0 and the system
> - * year will be parsed as 1960 which is not a valid UNIX time and will
> - * cause many applications to fail mysteriously.
> - */
> -static int mrst_read_time(struct device *dev, struct rtc_time *time)
> -{
> -	unsigned long flags;
> -
> -	if (vrtc_is_updating())
> -		msleep(20);
> -
> -	spin_lock_irqsave(&rtc_lock, flags);
> -	time->tm_sec = vrtc_cmos_read(RTC_SECONDS);
> -	time->tm_min = vrtc_cmos_read(RTC_MINUTES);
> -	time->tm_hour = vrtc_cmos_read(RTC_HOURS);
> -	time->tm_mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
> -	time->tm_mon = vrtc_cmos_read(RTC_MONTH);
> -	time->tm_year = vrtc_cmos_read(RTC_YEAR);
> -	spin_unlock_irqrestore(&rtc_lock, flags);
> -
> -	/* Adjust for the 1972/1900 */
> -	time->tm_year += 72;
> -	time->tm_mon--;
> -	return 0;
> -}
> -
> -static int mrst_set_time(struct device *dev, struct rtc_time *time)
> -{
> -	int ret;
> -	unsigned long flags;
> -	unsigned char mon, day, hrs, min, sec;
> -	unsigned int yrs;
> -
> -	yrs = time->tm_year;
> -	mon = time->tm_mon + 1;   /* tm_mon starts at zero */
> -	day = time->tm_mday;
> -	hrs = time->tm_hour;
> -	min = time->tm_min;
> -	sec = time->tm_sec;
> -
> -	if (yrs < 72 || yrs > 172)
> -		return -EINVAL;
> -	yrs -= 72;
> -
> -	spin_lock_irqsave(&rtc_lock, flags);
> -
> -	vrtc_cmos_write(yrs, RTC_YEAR);
> -	vrtc_cmos_write(mon, RTC_MONTH);
> -	vrtc_cmos_write(day, RTC_DAY_OF_MONTH);
> -	vrtc_cmos_write(hrs, RTC_HOURS);
> -	vrtc_cmos_write(min, RTC_MINUTES);
> -	vrtc_cmos_write(sec, RTC_SECONDS);
> -
> -	spin_unlock_irqrestore(&rtc_lock, flags);
> -
> -	ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETTIME);
> -	return ret;
> -}
> -
> -static int mrst_read_alarm(struct device *dev, struct rtc_wkalrm *t)
> -{
> -	struct mrst_rtc	*mrst = dev_get_drvdata(dev);
> -	unsigned char rtc_control;
> -
> -	if (mrst->irq <= 0)
> -		return -EIO;
> -
> -	/* vRTC only supports binary mode */
> -	spin_lock_irq(&rtc_lock);
> -	t->time.tm_sec = vrtc_cmos_read(RTC_SECONDS_ALARM);
> -	t->time.tm_min = vrtc_cmos_read(RTC_MINUTES_ALARM);
> -	t->time.tm_hour = vrtc_cmos_read(RTC_HOURS_ALARM);
> -
> -	rtc_control = vrtc_cmos_read(RTC_CONTROL);
> -	spin_unlock_irq(&rtc_lock);
> -
> -	t->enabled = !!(rtc_control & RTC_AIE);
> -	t->pending = 0;
> -
> -	return 0;
> -}
> -
> -static void mrst_checkintr(struct mrst_rtc *mrst, unsigned char rtc_control)
> -{
> -	unsigned char	rtc_intr;
> -
> -	/*
> -	 * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
> -	 * allegedly some older rtcs need that to handle irqs properly
> -	 */
> -	rtc_intr = vrtc_cmos_read(RTC_INTR_FLAGS);
> -	rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
> -	if (is_intr(rtc_intr))
> -		rtc_update_irq(mrst->rtc, 1, rtc_intr);
> -}
> -
> -static void mrst_irq_enable(struct mrst_rtc *mrst, unsigned char mask)
> -{
> -	unsigned char	rtc_control;
> -
> -	/*
> -	 * Flush any pending IRQ status, notably for update irqs,
> -	 * before we enable new IRQs
> -	 */
> -	rtc_control = vrtc_cmos_read(RTC_CONTROL);
> -	mrst_checkintr(mrst, rtc_control);
> -
> -	rtc_control |= mask;
> -	vrtc_cmos_write(rtc_control, RTC_CONTROL);
> -
> -	mrst_checkintr(mrst, rtc_control);
> -}
> -
> -static void mrst_irq_disable(struct mrst_rtc *mrst, unsigned char mask)
> -{
> -	unsigned char	rtc_control;
> -
> -	rtc_control = vrtc_cmos_read(RTC_CONTROL);
> -	rtc_control &= ~mask;
> -	vrtc_cmos_write(rtc_control, RTC_CONTROL);
> -	mrst_checkintr(mrst, rtc_control);
> -}
> -
> -static int mrst_set_alarm(struct device *dev, struct rtc_wkalrm *t)
> -{
> -	struct mrst_rtc	*mrst = dev_get_drvdata(dev);
> -	unsigned char hrs, min, sec;
> -	int ret = 0;
> -
> -	if (!mrst->irq)
> -		return -EIO;
> -
> -	hrs = t->time.tm_hour;
> -	min = t->time.tm_min;
> -	sec = t->time.tm_sec;
> -
> -	spin_lock_irq(&rtc_lock);
> -	/* Next rtc irq must not be from previous alarm setting */
> -	mrst_irq_disable(mrst, RTC_AIE);
> -
> -	/* Update alarm */
> -	vrtc_cmos_write(hrs, RTC_HOURS_ALARM);
> -	vrtc_cmos_write(min, RTC_MINUTES_ALARM);
> -	vrtc_cmos_write(sec, RTC_SECONDS_ALARM);
> -
> -	spin_unlock_irq(&rtc_lock);
> -
> -	ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETALARM);
> -	if (ret)
> -		return ret;
> -
> -	spin_lock_irq(&rtc_lock);
> -	if (t->enabled)
> -		mrst_irq_enable(mrst, RTC_AIE);
> -
> -	spin_unlock_irq(&rtc_lock);
> -
> -	return 0;
> -}
> -
> -/* Currently, the vRTC doesn't support UIE ON/OFF */
> -static int mrst_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
> -{
> -	struct mrst_rtc	*mrst = dev_get_drvdata(dev);
> -	unsigned long	flags;
> -
> -	spin_lock_irqsave(&rtc_lock, flags);
> -	if (enabled)
> -		mrst_irq_enable(mrst, RTC_AIE);
> -	else
> -		mrst_irq_disable(mrst, RTC_AIE);
> -	spin_unlock_irqrestore(&rtc_lock, flags);
> -	return 0;
> -}
> -
> -
> -#if IS_ENABLED(CONFIG_RTC_INTF_PROC)
> -
> -static int mrst_procfs(struct device *dev, struct seq_file *seq)
> -{
> -	unsigned char	rtc_control;
> -
> -	spin_lock_irq(&rtc_lock);
> -	rtc_control = vrtc_cmos_read(RTC_CONTROL);
> -	spin_unlock_irq(&rtc_lock);
> -
> -	seq_printf(seq,
> -		   "periodic_IRQ\t: %s\n"
> -		   "alarm\t\t: %s\n"
> -		   "BCD\t\t: no\n"
> -		   "periodic_freq\t: daily (not adjustable)\n",
> -		   (rtc_control & RTC_PIE) ? "on" : "off",
> -		   (rtc_control & RTC_AIE) ? "on" : "off");
> -
> -	return 0;
> -}
> -
> -#else
> -#define	mrst_procfs	NULL
> -#endif
> -
> -static const struct rtc_class_ops mrst_rtc_ops = {
> -	.read_time	= mrst_read_time,
> -	.set_time	= mrst_set_time,
> -	.read_alarm	= mrst_read_alarm,
> -	.set_alarm	= mrst_set_alarm,
> -	.proc		= mrst_procfs,
> -	.alarm_irq_enable = mrst_rtc_alarm_irq_enable,
> -};
> -
> -static struct mrst_rtc	mrst_rtc;
> -
> -/*
> - * When vRTC IRQ is captured by SCU FW, FW will clear the AIE bit in
> - * Reg B, so no need for this driver to clear it
> - */
> -static irqreturn_t mrst_rtc_irq(int irq, void *p)
> -{
> -	u8 irqstat;
> -
> -	spin_lock(&rtc_lock);
> -	/* This read will clear all IRQ flags inside Reg C */
> -	irqstat = vrtc_cmos_read(RTC_INTR_FLAGS);
> -	spin_unlock(&rtc_lock);
> -
> -	irqstat &= RTC_IRQMASK | RTC_IRQF;
> -	if (is_intr(irqstat)) {
> -		rtc_update_irq(p, 1, irqstat);
> -		return IRQ_HANDLED;
> -	}
> -	return IRQ_NONE;
> -}
> -
> -static int vrtc_mrst_do_probe(struct device *dev, struct resource *iomem,
> -			      int rtc_irq)
> -{
> -	int retval = 0;
> -	unsigned char rtc_control;
> -
> -	/* There can be only one ... */
> -	if (mrst_rtc.dev)
> -		return -EBUSY;
> -
> -	if (!iomem)
> -		return -ENODEV;
> -
> -	iomem = devm_request_mem_region(dev, iomem->start, resource_size(iomem),
> -					driver_name);
> -	if (!iomem) {
> -		dev_dbg(dev, "i/o mem already in use.\n");
> -		return -EBUSY;
> -	}
> -
> -	mrst_rtc.irq = rtc_irq;
> -	mrst_rtc.dev = dev;
> -	dev_set_drvdata(dev, &mrst_rtc);
> -
> -	mrst_rtc.rtc = devm_rtc_allocate_device(dev);
> -	if (IS_ERR(mrst_rtc.rtc))
> -		return PTR_ERR(mrst_rtc.rtc);
> -
> -	mrst_rtc.rtc->ops = &mrst_rtc_ops;
> -
> -	rename_region(iomem, dev_name(&mrst_rtc.rtc->dev));
> -
> -	spin_lock_irq(&rtc_lock);
> -	mrst_irq_disable(&mrst_rtc, RTC_PIE | RTC_AIE);
> -	rtc_control = vrtc_cmos_read(RTC_CONTROL);
> -	spin_unlock_irq(&rtc_lock);
> -
> -	if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY)))
> -		dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n");
> -
> -	if (rtc_irq) {
> -		retval = devm_request_irq(dev, rtc_irq, mrst_rtc_irq,
> -					  0, dev_name(&mrst_rtc.rtc->dev),
> -					  mrst_rtc.rtc);
> -		if (retval < 0) {
> -			dev_dbg(dev, "IRQ %d is already in use, err %d\n",
> -				rtc_irq, retval);
> -			goto cleanup0;
> -		}
> -	}
> -
> -	retval = devm_rtc_register_device(mrst_rtc.rtc);
> -	if (retval)
> -		goto cleanup0;
> -
> -	dev_dbg(dev, "initialised\n");
> -	return 0;
> -
> -cleanup0:
> -	mrst_rtc.dev = NULL;
> -	dev_err(dev, "rtc-mrst: unable to initialise\n");
> -	return retval;
> -}
> -
> -static void rtc_mrst_do_shutdown(void)
> -{
> -	spin_lock_irq(&rtc_lock);
> -	mrst_irq_disable(&mrst_rtc, RTC_IRQMASK);
> -	spin_unlock_irq(&rtc_lock);
> -}
> -
> -static void rtc_mrst_do_remove(struct device *dev)
> -{
> -	struct mrst_rtc	*mrst = dev_get_drvdata(dev);
> -
> -	rtc_mrst_do_shutdown();
> -
> -	mrst->rtc = NULL;
> -	mrst->dev = NULL;
> -}
> -
> -#ifdef CONFIG_PM_SLEEP
> -static int mrst_suspend(struct device *dev)
> -{
> -	struct mrst_rtc	*mrst = dev_get_drvdata(dev);
> -	unsigned char	tmp;
> -
> -	/* Only the alarm might be a wakeup event source */
> -	spin_lock_irq(&rtc_lock);
> -	mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL);
> -	if (tmp & (RTC_PIE | RTC_AIE)) {
> -		unsigned char	mask;
> -
> -		if (device_may_wakeup(dev))
> -			mask = RTC_IRQMASK & ~RTC_AIE;
> -		else
> -			mask = RTC_IRQMASK;
> -		tmp &= ~mask;
> -		vrtc_cmos_write(tmp, RTC_CONTROL);
> -
> -		mrst_checkintr(mrst, tmp);
> -	}
> -	spin_unlock_irq(&rtc_lock);
> -
> -	if (tmp & RTC_AIE) {
> -		mrst->enabled_wake = 1;
> -		enable_irq_wake(mrst->irq);
> -	}
> -
> -	dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n",
> -			(tmp & RTC_AIE) ? ", alarm may wake" : "",
> -			tmp);
> -
> -	return 0;
> -}
> -
> -/*
> - * We want RTC alarms to wake us from the deep power saving state
> - */
> -static inline int mrst_poweroff(struct device *dev)
> -{
> -	return mrst_suspend(dev);
> -}
> -
> -static int mrst_resume(struct device *dev)
> -{
> -	struct mrst_rtc	*mrst = dev_get_drvdata(dev);
> -	unsigned char tmp = mrst->suspend_ctrl;
> -
> -	/* Re-enable any irqs previously active */
> -	if (tmp & RTC_IRQMASK) {
> -		unsigned char	mask;
> -
> -		if (mrst->enabled_wake) {
> -			disable_irq_wake(mrst->irq);
> -			mrst->enabled_wake = 0;
> -		}
> -
> -		spin_lock_irq(&rtc_lock);
> -		do {
> -			vrtc_cmos_write(tmp, RTC_CONTROL);
> -
> -			mask = vrtc_cmos_read(RTC_INTR_FLAGS);
> -			mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
> -			if (!is_intr(mask))
> -				break;
> -
> -			rtc_update_irq(mrst->rtc, 1, mask);
> -			tmp &= ~RTC_AIE;
> -		} while (mask & RTC_AIE);
> -		spin_unlock_irq(&rtc_lock);
> -	}
> -
> -	dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp);
> -
> -	return 0;
> -}
> -
> -static SIMPLE_DEV_PM_OPS(mrst_pm_ops, mrst_suspend, mrst_resume);
> -#define MRST_PM_OPS (&mrst_pm_ops)
> -
> -#else
> -#define MRST_PM_OPS NULL
> -
> -static inline int mrst_poweroff(struct device *dev)
> -{
> -	return -ENOSYS;
> -}
> -
> -#endif
> -
> -static int vrtc_mrst_platform_probe(struct platform_device *pdev)
> -{
> -	return vrtc_mrst_do_probe(&pdev->dev,
> -			platform_get_resource(pdev, IORESOURCE_MEM, 0),
> -			platform_get_irq(pdev, 0));
> -}
> -
> -static int vrtc_mrst_platform_remove(struct platform_device *pdev)
> -{
> -	rtc_mrst_do_remove(&pdev->dev);
> -	return 0;
> -}
> -
> -static void vrtc_mrst_platform_shutdown(struct platform_device *pdev)
> -{
> -	if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev))
> -		return;
> -
> -	rtc_mrst_do_shutdown();
> -}
> -
> -MODULE_ALIAS("platform:vrtc_mrst");
> -
> -static struct platform_driver vrtc_mrst_platform_driver = {
> -	.probe		= vrtc_mrst_platform_probe,
> -	.remove		= vrtc_mrst_platform_remove,
> -	.shutdown	= vrtc_mrst_platform_shutdown,
> -	.driver = {
> -		.name	= driver_name,
> -		.pm	= MRST_PM_OPS,
> -	}
> -};
> -
> -module_platform_driver(vrtc_mrst_platform_driver);
> -
> -MODULE_AUTHOR("Jacob Pan; Feng Tang");
> -MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
> -MODULE_LICENSE("GPL");
> -- 
> 2.29.2
> 

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com