From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Masahisa Kojima <masahisa.kojima@linaro.org>
Cc: "edk2-devel@lists.01.org" <edk2-devel@lists.01.org>,
Leif Lindholm <leif.lindholm@linaro.org>,
Yoshitoyo Osaki <osaki.yoshitoyo@socionext.com>
Subject: Re: [PATCH] Silicon/NXP/Pcf8563RealTimeClockLib: add rtc device initialization
Date: Mon, 18 Jun 2018 15:03:50 +0200 [thread overview]
Message-ID: <CAKv+Gu-td9UQBx=LdCY7_erKusEUi0fsprAnJZB_mF7FavwTxg@mail.gmail.com> (raw)
In-Reply-To: <20180618123155.2141-1-masahisa.kojima@linaro.org>
On 18 June 2018 at 14:31, <masahisa.kojima@linaro.org> wrote:
> From: Masahisa Kojima <masahisa.kojima@linaro.org>
>
> BcdToDecimal8() in LibGetTime() asserts with the
> following condition.
> 1) RTC device has not been initialized yet, RTC device
> returns indeterminate value
> 2) DEBUG build
>
> UEFI shell commands "date/time" expect that getting time from
> RTC should success when user sets the time. ShellCommandRunTime()
> performs GetTime()->update time->SetTime(), if the first
> GetTime() fails, user can not set time.
>
> To avoid this situation, even if it only occurs in DEBUG build,
> RTC driver should check the VL bit in the VL_seconds register.
> This VL bit is voltage-low detector, it means integrity of the
> clock information is not guaranteed if it sets to 1. In this
> case, driver set dummy date/time(01/01/2000 00:00:00) to
> proceed succeeding SetTime process.
>
> linux driver also checks this bit when driver gets the time
> from RTC. If VL bit is 1, linux driver discard the retreived
> time data.
>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
> Signed-off-by: Yoshitoyo Osaki <osaki.yoshitoyo@socionext.com>
> ---
> .../Pcf8563RealTimeClockLib.c | 32 ++++++++++++++++------
> 1 file changed, 23 insertions(+), 9 deletions(-)
>
> diff --git a/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.c b/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.c
> index fb58e1feb4..7be0d23eea 100644
> --- a/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.c
> +++ b/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.c
> @@ -19,11 +19,13 @@
> #include <Library/UefiBootServicesTableLib.h>
> #include <Library/UefiLib.h>
> #include <Library/UefiRuntimeLib.h>
> +#include <Library/BaseMemoryLib.h>
> #include <Protocol/I2cMaster.h>
>
> #define SLAVE_ADDRESS (FixedPcdGet8 (PcdI2cSlaveAddress))
> #define PCF8563_DATA_REG_OFFSET 0x2
>
> +#define PCF8563_CLOCK_INVALID 0x80
> #define PCF8563_SECONDS_MASK 0x7f
> #define PCF8563_MINUTES_MASK 0x7f
> #define PCF8563_HOURS_MASK 0x3f
> @@ -95,6 +97,7 @@ LibGetTime (
> RTC_DATETIME DateTime;
> EFI_STATUS Status;
> UINT8 Reg;
> + EFI_TIME InitTime;
>
> if (Time == NULL) {
> return EFI_INVALID_PARAMETER;
> @@ -122,15 +125,26 @@ LibGetTime (
> return EFI_DEVICE_ERROR;
> }
>
> - Time->Second = BcdToDecimal8 (DateTime.VL_seconds & PCF8563_SECONDS_MASK);
> - Time->Minute = BcdToDecimal8 (DateTime.Minutes & PCF8563_MINUTES_MASK);
> - Time->Hour = BcdToDecimal8 (DateTime.Hours & PCF8563_HOURS_MASK);
> - Time->Day = BcdToDecimal8 (DateTime.Days & PCF8563_DAYS_MASK);
> - Time->Month = BcdToDecimal8 (DateTime.Century_months & PCF8563_MONTHS_MASK);
> - Time->Year = BcdToDecimal8 (DateTime.Years) + EPOCH_BASE;
> -
> - if (DateTime.Century_months & PCF8563_CENTURY_MASK) {
> - Time->Year += 100;
> + if ((DateTime.VL_seconds & PCF8563_CLOCK_INVALID) != 0) {
Wouldn't it be better to return EFI_DEVICE_ERROR in this case?
> + InitTime.Second = 0;
> + InitTime.Minute = 0;
> + InitTime.Hour = 0;
> + InitTime.Day = 1;
> + InitTime.Month = 1;
> + InitTime.Year = EPOCH_BASE;
> + (VOID)LibSetTime (&InitTime);
> + (VOID)CopyMem (Time, &InitTime, sizeof(EFI_TIME));
> + } else {
> + Time->Second = BcdToDecimal8 (DateTime.VL_seconds & PCF8563_SECONDS_MASK);
> + Time->Minute = BcdToDecimal8 (DateTime.Minutes & PCF8563_MINUTES_MASK);
> + Time->Hour = BcdToDecimal8 (DateTime.Hours & PCF8563_HOURS_MASK);
> + Time->Day = BcdToDecimal8 (DateTime.Days & PCF8563_DAYS_MASK);
> + Time->Month = BcdToDecimal8 (DateTime.Century_months & PCF8563_MONTHS_MASK);
> + Time->Year = BcdToDecimal8 (DateTime.Years) + EPOCH_BASE;
> +
> + if (DateTime.Century_months & PCF8563_CENTURY_MASK) {
> + Time->Year += 100;
> + }
> }
>
> if (Capabilities != NULL) {
> --
> 2.14.2
>
next prev parent reply other threads:[~2018-06-18 13:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-18 12:31 [PATCH] Silicon/NXP/Pcf8563RealTimeClockLib: add rtc device initialization masahisa.kojima
2018-06-18 13:03 ` Ard Biesheuvel [this message]
2018-06-18 14:29 ` Masahisa Kojima
2018-06-18 15:51 ` Ard Biesheuvel
2018-06-18 23:56 ` Masahisa Kojima
2018-06-19 1:09 ` Masahisa Kojima
2018-06-19 8:02 ` Ard Biesheuvel
2018-06-20 1:54 ` Masahisa Kojima
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