[PATCH] mmc: core: Add support for the eMMC RTC feature in mmc_ops

[PATCH] mmc: core: Add support for the eMMC RTC feature in mmc_ops

[Nishad Kamdar]

This patch adds support to set the RTC information in
the eMMC device. This is based on the JEDEC specification.

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.

This patch has been tested successfully with the ioctl
interface. This patch has also been tested suceessfully
with all the three RTC_INFO_TYPEs.

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(+)

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 = {};
+	struct mmc_command cmd = {};
+	struct mmc_data data = {};
+	struct scatterlist sg;
+	int err = 0;
+	u8 *data_buf;
+
+	data_buf = kzalloc(512, GFP_KERNEL);
+	if (!data_buf)
+		return -ENOMEM;
+
+	if (rtc_info_type == 0x01 || rtc_info_type == 0x02 ||
+	    rtc_info_type == 0x03) {
+		data_buf[0] = 0x01;
+		data_buf[1] = 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 = &cmd;
+	mrq.data = &data;
+
+	cmd.opcode = MMC_SET_TIME;
+	cmd.arg = 0;
+	cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
+
+	data.blksz = 512;
+	data.blocks = 1;
+	data.flags = MMC_DATA_WRITE;
+	data.sg = &sg;
+	data.sg_len = 1;
+	sg_init_one(&sg, data_buf, 512);
+
+	mmc_set_data_timeout(&data, card);
+
+	mmc_wait_for_req(host, &mrq);
+
+	if (cmd.error) {
+		err = cmd.error;
+		goto out;
+	}
+
+	if (data.error) {
+		err = 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);
 
 #endif
 
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  */
 
   /* class 6 */
 #define MMC_SET_WRITE_PROT       28   /* ac   [31:0] data addr   R1b */
-- 
2.17.1

Re: [PATCH] mmc: core: Add support for the eMMC RTC feature in mmc_ops

[Stephen Boyd]

Quoting Nishad Kamdar (2021-12-05 11:10:08)
> 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 = {};
> +       struct mmc_command cmd = {};
> +       struct mmc_data data = {};
> +       struct scatterlist sg;
> +       int err = 0;
> +       u8 *data_buf;
> +
> +       data_buf = kzalloc(512, GFP_KERNEL);

Use some #define for 512 because it's used three times in here?

> +       if (!data_buf)
> +               return -ENOMEM;
> +
> +       if (rtc_info_type == 0x01 || rtc_info_type == 0x02 ||
> +           rtc_info_type == 0x03) {
> +               data_buf[0] = 0x01;
> +               data_buf[1] = rtc_info_type;
> +               memcpy(&data_buf[2], &seconds, sizeof(u64));

Use sizeof(seconds) instead?

> +       } else {
> +               pr_err("%s: invalid rtc_info_type %d\n",
> +                      mmc_hostname(host), rtc_info_type);
> +               kfree(data_buf);
> +               return -EINVAL;
> +       }
> +
> +       mrq.cmd = &cmd;
> +       mrq.data = &data;
> +
> +       cmd.opcode = MMC_SET_TIME;
> +       cmd.arg = 0;
> +       cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> +
> +       data.blksz = 512;
> +       data.blocks = 1;
> +       data.flags = MMC_DATA_WRITE;
> +       data.sg = &sg;
> +       data.sg_len = 1;
> +       sg_init_one(&sg, data_buf, 512);
> +
> +       mmc_set_data_timeout(&data, card);
> +
> +       mmc_wait_for_req(host, &mrq);
> +
> +       if (cmd.error) {
> +               err = cmd.error;
> +               goto out;
> +       }
> +
> +       if (data.error) {
> +               err = data.error;
> +               goto out;
> +       }

Why not

	if (cmd.error) {
		err = cmd.error;
	} else if (data.error) {
		err = data.error;
	} else {
		err = 0;
	}

> +out:

And then drop out: and the assignment of err to 0 up above?


> +       kfree(data_buf);
> +       return err;
> +}
> +EXPORT_SYMBOL_GPL(mmc_set_time);

Re: [PATCH] mmc: core: Add support for the eMMC RTC feature in mmc_ops

[Nishad Kamdar]

On Mon, Dec 06, 2021 at 12:44:14PM -0800, Stephen Boyd wrote:
> Quoting Nishad Kamdar (2021-12-05 11:10:08)
> > 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 = {};
> > +       struct mmc_command cmd = {};
> > +       struct mmc_data data = {};
> > +       struct scatterlist sg;
> > +       int err = 0;
> > +       u8 *data_buf;
> > +
> > +       data_buf = kzalloc(512, GFP_KERNEL);
> 
> Use some #define for 512 because it's used three times in here?
ok, but there is not #define for 512 as it is the variable block size
value. Hence, other functions in the same file like mmc_get_ext_csd() also use
the 512 value directly.

> > +       if (!data_buf)
> > +               return -ENOMEM;
> > +
> > +       if (rtc_info_type == 0x01 || rtc_info_type == 0x02 ||
> > +           rtc_info_type == 0x03) {
> > +               data_buf[0] = 0x01;
> > +               data_buf[1] = rtc_info_type;
> > +               memcpy(&data_buf[2], &seconds, sizeof(u64));
> 
> Use sizeof(seconds) instead?
> 
ok, I will do that.

> > +       } else {
> > +               pr_err("%s: invalid rtc_info_type %d\n",
> > +                      mmc_hostname(host), rtc_info_type);
> > +               kfree(data_buf);
> > +               return -EINVAL;
> > +       }
> > +
> > +       mrq.cmd = &cmd;
> > +       mrq.data = &data;
> > +
> > +       cmd.opcode = MMC_SET_TIME;
> > +       cmd.arg = 0;
> > +       cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> > +
> > +       data.blksz = 512;
> > +       data.blocks = 1;
> > +       data.flags = MMC_DATA_WRITE;
> > +       data.sg = &sg;
> > +       data.sg_len = 1;
> > +       sg_init_one(&sg, data_buf, 512);
> > +
> > +       mmc_set_data_timeout(&data, card);
> > +
> > +       mmc_wait_for_req(host, &mrq);
> > +
> > +       if (cmd.error) {
> > +               err = cmd.error;
> > +               goto out;
> > +       }
> > +
> > +       if (data.error) {
> > +               err = data.error;
> > +               goto out;
> > +       }
> 
> Why not
> 
> 	if (cmd.error) {
> 		err = cmd.error;
> 	} else if (data.error) {
> 		err = data.error;
> 	} else {
> 		err = 0;
> 	}
> 
> > +out:
> 
> And then drop out: and the assignment of err to 0 up above?
ok, I will do that.

> 
> > +       kfree(data_buf);
> > +       return err;
> > +}
> > +EXPORT_SYMBOL_GPL(mmc_set_time);

RE: [PATCH] mmc: core: Add support for the eMMC RTC feature in mmc_ops

[Avri Altman]

 
> This patch adds support to set the RTC information in
> the eMMC device. This is based on the JEDEC specification.
> 
> 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.
> 
> 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

> 
> 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(+)
> 
> 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 = {};
> +       struct mmc_command cmd = {};
> +       struct mmc_data data = {};
> +       struct scatterlist sg;
> +       int err = 0;
> +       u8 *data_buf;
> +
> +       data_buf = kzalloc(512, GFP_KERNEL);
> +       if (!data_buf)
> +               return -ENOMEM;
> +
> +       if (rtc_info_type == 0x01 || rtc_info_type == 0x02 ||
> +           rtc_info_type == 0x03) {
> +               data_buf[0] = 0x01;
> +               data_buf[1] = 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 = &cmd;
> +       mrq.data = &data;
> +
> +       cmd.opcode = MMC_SET_TIME;
> +       cmd.arg = 0;
> +       cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> +
> +       data.blksz = 512;
> +       data.blocks = 1;
> +       data.flags = MMC_DATA_WRITE;
> +       data.sg = &sg;
> +       data.sg_len = 1;
> +       sg_init_one(&sg, data_buf, 512);
> +
> +       mmc_set_data_timeout(&data, card);
> +
> +       mmc_wait_for_req(host, &mrq);
> +
> +       if (cmd.error) {
> +               err = cmd.error;
> +               goto out;
> +       }
> +
> +       if (data.error) {
> +               err = 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);
> 
>  #endif
> 
> 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  */
> 
>    /* class 6 */
>  #define MMC_SET_WRITE_PROT       28   /* ac   [31:0] data addr   R1b */
> --
> 2.17.1

Re: [PATCH] mmc: core: Add support for the eMMC RTC feature in mmc_ops

[Christian Löhle]

>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.

The spec does not mention anything special about error cases where the device can reject CMD49,
if you want some meaningful possibility of this anyway you should get the R1 of the command following on the CMD49, though,
as the raised error would likely be of detection mechanism type X, see table 68.
IMO it would likely only be bit 19 ("ERROR"), but maybe try it with some cards.
So CMD49->CMD13 would be an option.
You could also check if and how some cards reject CMD49 by e.g. setting 
Regards,
Christian

From: Nishad Kamdar <nishadkamdar@gmail.com>
Sent: Sunday, December 5, 2021 8:10 PM
To: Ulf Hansson; Jens Axboe; Adrian Hunter; Bean Huo; Shawn Lin; Avri Altman; Stephen Boyd; Huijin Park; Yue Hu; Wolfram Sang
Cc: Nishad Kamdar; Greg Kroah-Hartman; linux-mmc@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: [PATCH] mmc: core: Add support for the eMMC RTC feature in mmc_ops
    
This patch adds support to set the RTC information in
the eMMC device. This is based on the JEDEC specification.

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.

This patch has been tested successfully with the ioctl
interface. This patch has also been tested suceessfully
with all the three RTC_INFO_TYPEs.

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(+)

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 = {};
+       struct mmc_command cmd = {};
+       struct mmc_data data = {};
+       struct scatterlist sg;
+       int err = 0;
+       u8 *data_buf;
+
+       data_buf = kzalloc(512, GFP_KERNEL);
+       if (!data_buf)
+               return -ENOMEM;
+
+       if (rtc_info_type == 0x01 || rtc_info_type == 0x02 ||
+           rtc_info_type == 0x03) {
+               data_buf[0] = 0x01;
+               data_buf[1] = 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 = &cmd;
+       mrq.data = &data;
+
+       cmd.opcode = MMC_SET_TIME;
+       cmd.arg = 0;
+       cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
+
+       data.blksz = 512;
+       data.blocks = 1;
+       data.flags = MMC_DATA_WRITE;
+       data.sg = &sg;
+       data.sg_len = 1;
+       sg_init_one(&sg, data_buf, 512);
+
+       mmc_set_data_timeout(&data, card);
+
+       mmc_wait_for_req(host, &mrq);
+
+       if (cmd.error) {
+               err = cmd.error;
+               goto out;
+       }
+
+       if (data.error) {
+               err = 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);
 
 #endif
 
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  */
 
   /* class 6 */
 #define MMC_SET_WRITE_PROT       28   /* ac   [31:0] data addr   R1b */
-- 
2.17.1

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Re: [PATCH] mmc: core: Add support for the eMMC RTC feature in mmc_ops

[Nishad Kamdar]

On Tue, Dec 07, 2021 at 08:28:42AM +0000, Avri Altman wrote:
>  
> > This patch adds support to set the RTC information in
> > the eMMC device. This is based on the JEDEC specification.
> > 
> > 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.
> > 
> > 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
As per the spec, B51: Section 6.6.35:
Providing RTC info may be useful for internal maintainance operations.
And the host should send it on the following events:
- power-up
- wake-up
- Periodically
Hence IMO, the Kernel would be the right place of peforming this
operation.

Thanks for the response,
Nisha
> > 
> > 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(+)
> > 
> > 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 = {};
> > +       struct mmc_command cmd = {};
> > +       struct mmc_data data = {};
> > +       struct scatterlist sg;
> > +       int err = 0;
> > +       u8 *data_buf;
> > +
> > +       data_buf = kzalloc(512, GFP_KERNEL);
> > +       if (!data_buf)
> > +               return -ENOMEM;
> > +
> > +       if (rtc_info_type == 0x01 || rtc_info_type == 0x02 ||
> > +           rtc_info_type == 0x03) {
> > +               data_buf[0] = 0x01;
> > +               data_buf[1] = 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 = &cmd;
> > +       mrq.data = &data;
> > +
> > +       cmd.opcode = MMC_SET_TIME;
> > +       cmd.arg = 0;
> > +       cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> > +
> > +       data.blksz = 512;
> > +       data.blocks = 1;
> > +       data.flags = MMC_DATA_WRITE;
> > +       data.sg = &sg;
> > +       data.sg_len = 1;
> > +       sg_init_one(&sg, data_buf, 512);
> > +
> > +       mmc_set_data_timeout(&data, card);
> > +
> > +       mmc_wait_for_req(host, &mrq);
> > +
> > +       if (cmd.error) {
> > +               err = cmd.error;
> > +               goto out;
> > +       }
> > +
> > +       if (data.error) {
> > +               err = 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);
> > 
> >  #endif
> > 
> > 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  */
> > 
> >    /* class 6 */
> >  #define MMC_SET_WRITE_PROT       28   /* ac   [31:0] data addr   R1b */
> > --
> > 2.17.1
> 

RE: [PATCH] mmc: core: Add support for the eMMC RTC feature in mmc_ops

[Avri Altman]

> On Tue, Dec 07, 2021 at 08:28:42AM +0000, Avri Altman wrote:
> >
> > > This patch adds support to set the RTC information in the eMMC
> > > device. This is based on the JEDEC specification.
> > >
> > > 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.
> > >
> > > 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
> As per the spec, B51: Section 6.6.35:
> Providing RTC info may be useful for internal maintainance operations.
> And the host should send it on the following events:
> - power-up
> - wake-up
> - Periodically
> Hence IMO, the Kernel would be the right place of peforming this operation.
But your patch doesn't do that, is it?

Thanks,
Avri

Re: [PATCH] mmc: core: Add support for the eMMC RTC feature in mmc_ops

[Nishad Kamdar]

On Tue, Dec 07, 2021 at 09:33:46AM +0000, Avri Altman wrote:
> > On Tue, Dec 07, 2021 at 08:28:42AM +0000, Avri Altman wrote:
> > >
> > > > This patch adds support to set the RTC information in the eMMC
> > > > device. This is based on the JEDEC specification.
> > > >
> > > > 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.
> > > >
> > > > 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
> > As per the spec, B51: Section 6.6.35:
> > Providing RTC info may be useful for internal maintainance operations.
> > And the host should send it on the following events:
> > - power-up
> > - wake-up
> > - Periodically
> > Hence IMO, the Kernel would be the right place of peforming this operation.
> But your patch doesn't do that, is it?
>
Yes, That's because this operation may be device specific. In order to know when
to call this function may require eMMC firmware info.
This patch only adds support so that if the info is made available
in the future, a separate patch can be added to introduce the calling mechanism.

Thanks and Regards,
Nishad

> Thanks,
> Avri

Re: [PATCH] mmc: core: Add support for the eMMC RTC feature in mmc_ops

[Greg Kroah-Hartman]

On Tue, Dec 07, 2021 at 03:13:08PM +0530, Nishad Kamdar wrote:
> On Tue, Dec 07, 2021 at 09:33:46AM +0000, Avri Altman wrote:
> > > On Tue, Dec 07, 2021 at 08:28:42AM +0000, Avri Altman wrote:
> > > >
> > > > > This patch adds support to set the RTC information in the eMMC
> > > > > device. This is based on the JEDEC specification.
> > > > >
> > > > > 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.
> > > > >
> > > > > 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
> > > As per the spec, B51: Section 6.6.35:
> > > Providing RTC info may be useful for internal maintainance operations.
> > > And the host should send it on the following events:
> > > - power-up
> > > - wake-up
> > > - Periodically
> > > Hence IMO, the Kernel would be the right place of peforming this operation.
> > But your patch doesn't do that, is it?
> >
> Yes, That's because this operation may be device specific. In order to know when
> to call this function may require eMMC firmware info.
> This patch only adds support so that if the info is made available
> in the future, a separate patch can be added to introduce the calling mechanism.

We do not add code that is not actually used in the kernel tree.

Please submit a user of this new function, otherwise there is no need
for it at all.

thanks,

greg k-h