Re: [PATCH 1/2] rtc/ia64: remove legacy efirtc driver

From: Alexandre Belloni
Date: Wed Oct 23 2019 - 11:23:08 EST

On 23/10/2019 17:01:58+0200, Arnd Bergmann wrote:
> There are two EFI RTC drivers, the original drivers/char/efirtc.c
> driver and the more modern drivers/rtc/rtc-efi.c.
>
> Both implement the same interface, but the new one does so
> in a more portable way.
>
> Move everything over to that one and remove the old one.
>
> Cc: linux-ia64@xxxxxxxxxxxxxxx
> Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
> Cc: Tony Luck <tony.luck@xxxxxxxxx>
> Cc: Stephane Eranian <eranian@xxxxxxxxxx>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Acked-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>

> ---
> This was last discussed in early 2018 in
> https://lore.kernel.org/lkml/CAK8P3a0QZNY+K+V1HG056xCerz=_L2jh5UfZ+2LWkDqkw5Zznw@xxxxxxxxxxxxxx/
>
> Nobody ever replied there, so let's try this instead.
> If there is any reason to keep the driver after all,
> please let us know.
> ---
> arch/ia64/configs/bigsur_defconfig | 3 +-
> arch/ia64/configs/generic_defconfig | 3 +-
> arch/ia64/configs/gensparse_defconfig | 3 +-
> arch/ia64/configs/tiger_defconfig | 3 +-
> arch/ia64/configs/zx1_defconfig | 3 +-
> drivers/char/Kconfig | 4 -
> drivers/char/Makefile | 1 -
> drivers/char/efirtc.c | 366 --------------------------
> include/linux/miscdevice.h | 2 +-
> 9 files changed, 11 insertions(+), 377 deletions(-)
> delete mode 100644 drivers/char/efirtc.c
>
> diff --git a/arch/ia64/configs/bigsur_defconfig b/arch/ia64/configs/bigsur_defconfig
> index b630bd7351c4..f3ba813a5b80 100644
> --- a/arch/ia64/configs/bigsur_defconfig
> +++ b/arch/ia64/configs/bigsur_defconfig
> @@ -57,7 +57,8 @@ CONFIG_SERIAL_8250_CONSOLE=y
> CONFIG_SERIAL_8250_EXTENDED=y
> CONFIG_SERIAL_8250_SHARE_IRQ=y
> # CONFIG_HW_RANDOM is not set
> -CONFIG_EFI_RTC=y
> +CONFIG_RTC_CLASS=y
> +CONFIG_RTC_DRV_EFI=y
> CONFIG_I2C=y
> CONFIG_I2C_CHARDEV=y
> CONFIG_AGP=m
> diff --git a/arch/ia64/configs/generic_defconfig b/arch/ia64/configs/generic_defconfig
> index 661d90b3e148..cb267a07c57f 100644
> --- a/arch/ia64/configs/generic_defconfig
> +++ b/arch/ia64/configs/generic_defconfig
> @@ -94,7 +94,8 @@ CONFIG_SERIAL_8250_NR_UARTS=6
> CONFIG_SERIAL_8250_EXTENDED=y
> CONFIG_SERIAL_8250_SHARE_IRQ=y
> # CONFIG_HW_RANDOM is not set
> -CONFIG_EFI_RTC=y
> +CONFIG_RTC_CLASS=y
> +CONFIG_RTC_DRV_EFI=y
> CONFIG_RAW_DRIVER=m
> CONFIG_HPET=y
> CONFIG_AGP=m
> diff --git a/arch/ia64/configs/gensparse_defconfig b/arch/ia64/configs/gensparse_defconfig
> index 7844e6a956a4..7e25f2f031b6 100644
> --- a/arch/ia64/configs/gensparse_defconfig
> +++ b/arch/ia64/configs/gensparse_defconfig
> @@ -82,7 +82,8 @@ CONFIG_SERIAL_8250_NR_UARTS=6
> CONFIG_SERIAL_8250_EXTENDED=y
> CONFIG_SERIAL_8250_SHARE_IRQ=y
> # CONFIG_HW_RANDOM is not set
> -CONFIG_EFI_RTC=y
> +CONFIG_RTC_CLASS=y
> +CONFIG_RTC_DRV_EFI=y
> CONFIG_RAW_DRIVER=m
> CONFIG_HPET=y
> CONFIG_AGP=m
> diff --git a/arch/ia64/configs/tiger_defconfig b/arch/ia64/configs/tiger_defconfig
> index 1d6e2a01452b..3f486d5bdc2d 100644
> --- a/arch/ia64/configs/tiger_defconfig
> +++ b/arch/ia64/configs/tiger_defconfig
> @@ -86,7 +86,8 @@ CONFIG_SERIAL_8250_NR_UARTS=6
> CONFIG_SERIAL_8250_EXTENDED=y
> CONFIG_SERIAL_8250_SHARE_IRQ=y
> # CONFIG_HW_RANDOM is not set
> -CONFIG_EFI_RTC=y
> +CONFIG_RTC_CLASS=y
> +CONFIG_RTC_DRV_EFI=y
> CONFIG_RAW_DRIVER=m
> CONFIG_HPET=y
> CONFIG_AGP=m
> diff --git a/arch/ia64/configs/zx1_defconfig b/arch/ia64/configs/zx1_defconfig
> index 8c92e095f8bb..70788a500448 100644
> --- a/arch/ia64/configs/zx1_defconfig
> +++ b/arch/ia64/configs/zx1_defconfig
> @@ -69,7 +69,8 @@ CONFIG_SERIAL_8250_NR_UARTS=8
> CONFIG_SERIAL_8250_EXTENDED=y
> CONFIG_SERIAL_8250_SHARE_IRQ=y
> # CONFIG_HW_RANDOM is not set
> -CONFIG_EFI_RTC=y
> +CONFIG_RTC_CLASS=y
> +CONFIG_RTC_DRV_EFI=y
> CONFIG_I2C_CHARDEV=y
> CONFIG_AGP=y
> CONFIG_AGP_HP_ZX1=y
> diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
> index df0fc997dc3e..dabbf3f519c6 100644
> --- a/drivers/char/Kconfig
> +++ b/drivers/char/Kconfig
> @@ -297,10 +297,6 @@ config JS_RTC
> To compile this driver as a module, choose M here: the
> module will be called js-rtc.
>
> -config EFI_RTC
> - bool "EFI Real Time Clock Services"
> - depends on IA64
> -
> endif # RTC_LIB
>
> config DTLK
> diff --git a/drivers/char/Makefile b/drivers/char/Makefile
> index 7c5ea6f9df14..abe3138b1f5a 100644
> --- a/drivers/char/Makefile
> +++ b/drivers/char/Makefile
> @@ -22,7 +22,6 @@ obj-$(CONFIG_APPLICOM) += applicom.o
> obj-$(CONFIG_SONYPI) += sonypi.o
> obj-$(CONFIG_RTC) += rtc.o
> obj-$(CONFIG_HPET) += hpet.o
> -obj-$(CONFIG_EFI_RTC) += efirtc.o
> obj-$(CONFIG_XILINX_HWICAP) += xilinx_hwicap/
> obj-$(CONFIG_NVRAM) += nvram.o
> obj-$(CONFIG_TOSHIBA) += toshiba.o
> diff --git a/drivers/char/efirtc.c b/drivers/char/efirtc.c
> deleted file mode 100644
> index 4f73064d0c6f..000000000000
> --- a/drivers/char/efirtc.c
> +++ /dev/null
> @@ -1,366 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/*
> - * EFI Time Services Driver for Linux
> - *
> - * Copyright (C) 1999 Hewlett-Packard Co
> - * Copyright (C) 1999 Stephane Eranian <eranian@xxxxxxxxxx>
> - *
> - * Based on skeleton from the drivers/char/rtc.c driver by P. Gortmaker
> - *
> - * This code provides an architected & portable interface to the real time
> - * clock by using EFI instead of direct bit fiddling. The functionalities are
> - * quite different from the rtc.c driver. The only way to talk to the device
> - * is by using ioctl(). There is a /proc interface which provides the raw
> - * information.
> - *
> - * Please note that we have kept the API as close as possible to the
> - * legacy RTC. The standard /sbin/hwclock program should work normally
> - * when used to get/set the time.
> - *
> - * NOTES:
> - * - Locking is required for safe execution of EFI calls with regards
> - * to interrupts and SMP.
> - *
> - * TODO (December 1999):
> - * - provide the API to set/get the WakeUp Alarm (different from the
> - * rtc.c alarm).
> - * - SMP testing
> - * - Add module support
> - */
> -
> -#include <linux/types.h>
> -#include <linux/errno.h>
> -#include <linux/miscdevice.h>
> -#include <linux/init.h>
> -#include <linux/rtc.h>
> -#include <linux/proc_fs.h>
> -#include <linux/seq_file.h>
> -#include <linux/efi.h>
> -#include <linux/uaccess.h>
> -
> -
> -#define EFI_RTC_VERSION "0.4"
> -
> -#define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT)
> -/*
> - * EFI Epoch is 1/1/1998
> - */
> -#define EFI_RTC_EPOCH 1998
> -
> -static DEFINE_SPINLOCK(efi_rtc_lock);
> -
> -static long efi_rtc_ioctl(struct file *file, unsigned int cmd,
> - unsigned long arg);
> -
> -#define is_leap(year) \
> - ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
> -
> -static const unsigned short int __mon_yday[2][13] =
> -{
> - /* Normal years. */
> - { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
> - /* Leap years. */
> - { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
> -};
> -
> -/*
> - * returns day of the year [0-365]
> - */
> -static inline int
> -compute_yday(efi_time_t *eft)
> -{
> - /* efi_time_t.month is in the [1-12] so, we need -1 */
> - return __mon_yday[is_leap(eft->year)][eft->month-1]+ eft->day -1;
> -}
> -/*
> - * returns day of the week [0-6] 0=Sunday
> - *
> - * Don't try to provide a year that's before 1998, please !
> - */
> -static int
> -compute_wday(efi_time_t *eft)
> -{
> - int y;
> - int ndays = 0;
> -
> - if ( eft->year < 1998 ) {
> - printk(KERN_ERR "efirtc: EFI year < 1998, invalid date\n");
> - return -1;
> - }
> -
> - for(y=EFI_RTC_EPOCH; y < eft->year; y++ ) {
> - ndays += 365 + (is_leap(y) ? 1 : 0);
> - }
> - ndays += compute_yday(eft);
> -
> - /*
> - * 4=1/1/1998 was a Thursday
> - */
> - return (ndays + 4) % 7;
> -}
> -
> -static void
> -convert_to_efi_time(struct rtc_time *wtime, efi_time_t *eft)
> -{
> -
> - eft->year = wtime->tm_year + 1900;
> - eft->month = wtime->tm_mon + 1;
> - eft->day = wtime->tm_mday;
> - eft->hour = wtime->tm_hour;
> - eft->minute = wtime->tm_min;
> - eft->second = wtime->tm_sec;
> - eft->nanosecond = 0;
> - eft->daylight = wtime->tm_isdst ? EFI_ISDST: 0;
> - eft->timezone = EFI_UNSPECIFIED_TIMEZONE;
> -}
> -
> -static void
> -convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
> -{
> - memset(wtime, 0, sizeof(*wtime));
> - wtime->tm_sec = eft->second;
> - wtime->tm_min = eft->minute;
> - wtime->tm_hour = eft->hour;
> - wtime->tm_mday = eft->day;
> - wtime->tm_mon = eft->month - 1;
> - wtime->tm_year = eft->year - 1900;
> -
> - /* day of the week [0-6], Sunday=0 */
> - wtime->tm_wday = compute_wday(eft);
> -
> - /* day in the year [1-365]*/
> - wtime->tm_yday = compute_yday(eft);
> -
> -
> - switch (eft->daylight & EFI_ISDST) {
> - case EFI_ISDST:
> - wtime->tm_isdst = 1;
> - break;
> - case EFI_TIME_ADJUST_DAYLIGHT:
> - wtime->tm_isdst = 0;
> - break;
> - default:
> - wtime->tm_isdst = -1;
> - }
> -}
> -
> -static long efi_rtc_ioctl(struct file *file, unsigned int cmd,
> - unsigned long arg)
> -{
> -
> - efi_status_t status;
> - unsigned long flags;
> - efi_time_t eft;
> - efi_time_cap_t cap;
> - struct rtc_time wtime;
> - struct rtc_wkalrm __user *ewp;
> - unsigned char enabled, pending;
> -
> - switch (cmd) {
> - case RTC_UIE_ON:
> - case RTC_UIE_OFF:
> - case RTC_PIE_ON:
> - case RTC_PIE_OFF:
> - case RTC_AIE_ON:
> - case RTC_AIE_OFF:
> - case RTC_ALM_SET:
> - case RTC_ALM_READ:
> - case RTC_IRQP_READ:
> - case RTC_IRQP_SET:
> - case RTC_EPOCH_READ:
> - case RTC_EPOCH_SET:
> - return -EINVAL;
> -
> - case RTC_RD_TIME:
> - spin_lock_irqsave(&efi_rtc_lock, flags);
> -
> - status = efi.get_time(&eft, &cap);
> -
> - spin_unlock_irqrestore(&efi_rtc_lock,flags);
> -
> - if (status != EFI_SUCCESS) {
> - /* should never happen */
> - printk(KERN_ERR "efitime: can't read time\n");
> - return -EINVAL;
> - }
> -
> - convert_from_efi_time(&eft, &wtime);
> -
> - return copy_to_user((void __user *)arg, &wtime,
> - sizeof (struct rtc_time)) ? - EFAULT : 0;
> -
> - case RTC_SET_TIME:
> -
> - if (!capable(CAP_SYS_TIME)) return -EACCES;
> -
> - if (copy_from_user(&wtime, (struct rtc_time __user *)arg,
> - sizeof(struct rtc_time)) )
> - return -EFAULT;
> -
> - convert_to_efi_time(&wtime, &eft);
> -
> - spin_lock_irqsave(&efi_rtc_lock, flags);
> -
> - status = efi.set_time(&eft);
> -
> - spin_unlock_irqrestore(&efi_rtc_lock,flags);
> -
> - return status == EFI_SUCCESS ? 0 : -EINVAL;
> -
> - case RTC_WKALM_SET:
> -
> - if (!capable(CAP_SYS_TIME)) return -EACCES;
> -
> - ewp = (struct rtc_wkalrm __user *)arg;
> -
> - if ( get_user(enabled, &ewp->enabled)
> - || copy_from_user(&wtime, &ewp->time, sizeof(struct rtc_time)) )
> - return -EFAULT;
> -
> - convert_to_efi_time(&wtime, &eft);
> -
> - spin_lock_irqsave(&efi_rtc_lock, flags);
> - /*
> - * XXX Fixme:
> - * As of EFI 0.92 with the firmware I have on my
> - * machine this call does not seem to work quite
> - * right
> - */
> - status = efi.set_wakeup_time((efi_bool_t)enabled, &eft);
> -
> - spin_unlock_irqrestore(&efi_rtc_lock,flags);
> -
> - return status == EFI_SUCCESS ? 0 : -EINVAL;
> -
> - case RTC_WKALM_RD:
> -
> - spin_lock_irqsave(&efi_rtc_lock, flags);
> -
> - status = efi.get_wakeup_time((efi_bool_t *)&enabled, (efi_bool_t *)&pending, &eft);
> -
> - spin_unlock_irqrestore(&efi_rtc_lock,flags);
> -
> - if (status != EFI_SUCCESS) return -EINVAL;
> -
> - ewp = (struct rtc_wkalrm __user *)arg;
> -
> - if ( put_user(enabled, &ewp->enabled)
> - || put_user(pending, &ewp->pending)) return -EFAULT;
> -
> - convert_from_efi_time(&eft, &wtime);
> -
> - return copy_to_user(&ewp->time, &wtime,
> - sizeof(struct rtc_time)) ? -EFAULT : 0;
> - }
> - return -ENOTTY;
> -}
> -
> -/*
> - * The various file operations we support.
> - */
> -
> -static const struct file_operations efi_rtc_fops = {
> - .owner = THIS_MODULE,
> - .unlocked_ioctl = efi_rtc_ioctl,
> - .llseek = no_llseek,
> -};
> -
> -static struct miscdevice efi_rtc_dev= {
> - EFI_RTC_MINOR,
> - "efirtc",
> - &efi_rtc_fops
> -};
> -
> -/*
> - * We export RAW EFI information to /proc/driver/efirtc
> - */
> -static int efi_rtc_proc_show(struct seq_file *m, void *v)
> -{
> - efi_time_t eft, alm;
> - efi_time_cap_t cap;
> - efi_bool_t enabled, pending;
> - unsigned long flags;
> -
> - memset(&eft, 0, sizeof(eft));
> - memset(&alm, 0, sizeof(alm));
> - memset(&cap, 0, sizeof(cap));
> -
> - spin_lock_irqsave(&efi_rtc_lock, flags);
> -
> - efi.get_time(&eft, &cap);
> - efi.get_wakeup_time(&enabled, &pending, &alm);
> -
> - spin_unlock_irqrestore(&efi_rtc_lock,flags);
> -
> - seq_printf(m,
> - "Time : %u:%u:%u.%09u\n"
> - "Date : %u-%u-%u\n"
> - "Daylight : %u\n",
> - eft.hour, eft.minute, eft.second, eft.nanosecond,
> - eft.year, eft.month, eft.day,
> - eft.daylight);
> -
> - if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
> - seq_puts(m, "Timezone : unspecified\n");
> - else
> - /* XXX fixme: convert to string? */
> - seq_printf(m, "Timezone : %u\n", eft.timezone);
> -
> -
> - seq_printf(m,
> - "Alarm Time : %u:%u:%u.%09u\n"
> - "Alarm Date : %u-%u-%u\n"
> - "Alarm Daylight : %u\n"
> - "Enabled : %s\n"
> - "Pending : %s\n",
> - alm.hour, alm.minute, alm.second, alm.nanosecond,
> - alm.year, alm.month, alm.day,
> - alm.daylight,
> - enabled == 1 ? "yes" : "no",
> - pending == 1 ? "yes" : "no");
> -
> - if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
> - seq_puts(m, "Timezone : unspecified\n");
> - else
> - /* XXX fixme: convert to string? */
> - seq_printf(m, "Timezone : %u\n", alm.timezone);
> -
> - /*
> - * now prints the capabilities
> - */
> - seq_printf(m,
> - "Resolution : %u\n"
> - "Accuracy : %u\n"
> - "SetstoZero : %u\n",
> - cap.resolution, cap.accuracy, cap.sets_to_zero);
> -
> - return 0;
> -}
> -static int __init
> -efi_rtc_init(void)
> -{
> - int ret;
> - struct proc_dir_entry *dir;
> -
> - printk(KERN_INFO "EFI Time Services Driver v%s\n", EFI_RTC_VERSION);
> -
> - ret = misc_register(&efi_rtc_dev);
> - if (ret) {
> - printk(KERN_ERR "efirtc: can't misc_register on minor=%d\n",
> - EFI_RTC_MINOR);
> - return ret;
> - }
> -
> - dir = proc_create_single("driver/efirtc", 0, NULL, efi_rtc_proc_show);
> - if (dir == NULL) {
> - printk(KERN_ERR "efirtc: can't create /proc/driver/efirtc.\n");
> - misc_deregister(&efi_rtc_dev);
> - return -1;
> - }
> - return 0;
> -}
> -device_initcall(efi_rtc_init);
> -
> -/*
> -MODULE_LICENSE("GPL");
> -*/
> diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
> index 3247a3dc7934..4ab05916046c 100644
> --- a/include/linux/miscdevice.h
> +++ b/include/linux/miscdevice.h
> @@ -25,7 +25,7 @@
> #define TEMP_MINOR 131 /* Temperature Sensor */
> #define APM_MINOR_DEV 134
> #define RTC_MINOR 135
> -#define EFI_RTC_MINOR 136 /* EFI Time services */
> +/*#define EFI_RTC_MINOR 136 was EFI Time services */
> #define VHCI_MINOR 137
> #define SUN_OPENPROM_MINOR 139
> #define DMAPI_MINOR 140 /* unused */
> --
> 2.20.0
>

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