From:   Avri Altman <Avri.Altman@wdc.com>
To:     Nishad Kamdar <nishadkamdar@gmail.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Jens Axboe <axboe@kernel.dk>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Bean Huo <beanhuo@micron.com>,
        Shawn Lin <shawn.lin@rock-chips.com>,
        Stephen Boyd <swboyd@chromium.org>,
        Huijin Park <huijin.park@samsung.com>,
        Yue Hu <huyue2@yulong.com>,
        Wolfram Sang <wsa+renesas@sang-engineering.com>
CC:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] mmc: core: Add support for the eMMC RTC feature in
 mmc_ops
Thread-Topic: [PATCH] mmc: core: Add support for the eMMC RTC feature in
 mmc_ops
Thread-Index: AQHX6gvX/BT/iVXcEEKk0MhaGQh9w6wms6wQ
Date:   Tue, 7 Dec 2021 08:28:42 +0000
Message-ID: <DM6PR04MB657527FCF325EA9760032DA5FC6E9@DM6PR04MB6575.namprd04.prod.outlook.com>
References: <20211205191009.32454-1-nishadkamdar@gmail.com>
In-Reply-To: <20211205191009.32454-1-nishadkamdar@gmail.com>
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=20
> This patch adds support to set the RTC information in
> the eMMC device. This is based on the JEDEC specification.
>=20
> There is no way however, to read the RTC time from the
> device. Hence we rely on the response of the CMD49 to
> confirm the completion of the operation.
>=20
> This patch has been tested successfully with the ioctl
> interface. This patch has also been tested suceessfully
> with all the three RTC_INFO_TYPEs.
If this is triggered from user-space via ioctl anyway,
Why do we need this command to be implemented in the kernel?
Why not just add this to mmc-utils?

Thanks,
Avri

>=20
> Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
> ---
>  drivers/mmc/core/mmc_ops.c | 59
> ++++++++++++++++++++++++++++++++++++++
>  drivers/mmc/core/mmc_ops.h |  2 ++
>  include/linux/mmc/mmc.h    |  1 +
>  3 files changed, 62 insertions(+)
>=20
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index d63d1c735335..490372341b3b 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -1063,3 +1063,62 @@ int mmc_sanitize(struct mmc_card *card,
> unsigned int timeout_ms)
>         return err;
>  }
>  EXPORT_SYMBOL_GPL(mmc_sanitize);
> +
> +int mmc_set_time(struct mmc_card *card, struct mmc_host *host,
> +                u8 rtc_info_type, u64 seconds)
> +{
> +       struct mmc_request mrq =3D {};
> +       struct mmc_command cmd =3D {};
> +       struct mmc_data data =3D {};
> +       struct scatterlist sg;
> +       int err =3D 0;
> +       u8 *data_buf;
> +
> +       data_buf =3D kzalloc(512, GFP_KERNEL);
> +       if (!data_buf)
> +               return -ENOMEM;
> +
> +       if (rtc_info_type =3D=3D 0x01 || rtc_info_type =3D=3D 0x02 ||
> +           rtc_info_type =3D=3D 0x03) {
> +               data_buf[0] =3D 0x01;
> +               data_buf[1] =3D rtc_info_type;
> +               memcpy(&data_buf[2], &seconds, sizeof(u64));
> +       } else {
> +               pr_err("%s: invalid rtc_info_type %d\n",
> +                      mmc_hostname(host), rtc_info_type);
> +               kfree(data_buf);
> +               return -EINVAL;
> +       }
> +
> +       mrq.cmd =3D &cmd;
> +       mrq.data =3D &data;
> +
> +       cmd.opcode =3D MMC_SET_TIME;
> +       cmd.arg =3D 0;
> +       cmd.flags =3D MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> +
> +       data.blksz =3D 512;
> +       data.blocks =3D 1;
> +       data.flags =3D MMC_DATA_WRITE;
> +       data.sg =3D &sg;
> +       data.sg_len =3D 1;
> +       sg_init_one(&sg, data_buf, 512);
> +
> +       mmc_set_data_timeout(&data, card);
> +
> +       mmc_wait_for_req(host, &mrq);
> +
> +       if (cmd.error) {
> +               err =3D cmd.error;
> +               goto out;
> +       }
> +
> +       if (data.error) {
> +               err =3D data.error;
> +               goto out;
> +       }
> +out:
> +       kfree(data_buf);
> +       return err;
> +}
> +EXPORT_SYMBOL_GPL(mmc_set_time);
> diff --git a/drivers/mmc/core/mmc_ops.h b/drivers/mmc/core/mmc_ops.h
> index 9c813b851d0b..0c8695d1b363 100644
> --- a/drivers/mmc/core/mmc_ops.h
> +++ b/drivers/mmc/core/mmc_ops.h
> @@ -55,6 +55,8 @@ void mmc_run_bkops(struct mmc_card *card);
>  int mmc_cmdq_enable(struct mmc_card *card);
>  int mmc_cmdq_disable(struct mmc_card *card);
>  int mmc_sanitize(struct mmc_card *card, unsigned int timeout_ms);
> +int mmc_set_time(struct mmc_card *card, struct mmc_host *host,
> +                u8 rtc_info_type, u64 seconds);
>=20
>  #endif
>=20
> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
> index d9a65c6a8816..52a3bf873d50 100644
> --- a/include/linux/mmc/mmc.h
> +++ b/include/linux/mmc/mmc.h
> @@ -64,6 +64,7 @@
>  #define MMC_WRITE_MULTIPLE_BLOCK 25   /* adtc                    R1  */
>  #define MMC_PROGRAM_CID          26   /* adtc                    R1  */
>  #define MMC_PROGRAM_CSD          27   /* adtc                    R1  */
> +#define MMC_SET_TIME            49   /* adtc                    R1  */
>=20
>    /* class 6 */
>  #define MMC_SET_WRITE_PROT       28   /* ac   [31:0] data addr   R1b */
> --
> 2.17.1