soc: imx-scu: Add SoC UID(unique identifier) support

Commit Message

Anson Huang June 26, 2019, 7:07 a.m. UTC

From: Anson Huang <[e-mail]>

Add i.MX SCU SoC's UID(unique identifier) support, user
can read it from sysfs:

root@imx8qxpmek:~# cat /sys/devices/soc0/soc_uid
7B64280B57AC1898

Signed-off-by: Anson Huang <[e-mail]>
---
 drivers/soc/imx/soc-imx-scu.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

Comments

Daniel Baluta June 26, 2019, 12:41 p.m. UTC | #1

On Wed, Jun 26, 2019 at 10:06 AM <[e-mail]> wrote:
>
> From: Anson Huang <[e-mail]>
>
> Add i.MX SCU SoC's UID(unique identifier) support, user
> can read it from sysfs:
>
> root@imx8qxpmek:~# cat /sys/devices/soc0/soc_uid
> 7B64280B57AC1898
>
> Signed-off-by: Anson Huang <[e-mail]>
> ---
>  drivers/soc/imx/soc-imx-scu.c | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
>
> diff --git a/drivers/soc/imx/soc-imx-scu.c b/drivers/soc/imx/soc-imx-scu.c
> index 676f612..8d322a1 100644
> --- a/drivers/soc/imx/soc-imx-scu.c
> +++ b/drivers/soc/imx/soc-imx-scu.c
> @@ -27,6 +27,36 @@ struct imx_sc_msg_misc_get_soc_id {
>         } data;
>  } __packed;
>
> +struct imx_sc_msg_misc_get_soc_uid {
> +       struct imx_sc_rpc_msg hdr;
> +       u32 uid_low;
> +       u32 uid_high;
> +} __packed;
> +
> +static ssize_t soc_uid_show(struct device *dev,
> +                           struct device_attribute *attr, char *buf)
> +{
> +       struct imx_sc_msg_misc_get_soc_uid msg;
> +       struct imx_sc_rpc_msg *hdr = &msg.hdr;
> +       u64 soc_uid;
> +
> +       hdr->ver = IMX_SC_RPC_VERSION;
> +       hdr->svc = IMX_SC_RPC_SVC_MISC;
> +       hdr->func = IMX_SC_MISC_FUNC_UNIQUE_ID;
> +       hdr->size = 1;
> +
> +       /* the return value of SCU FW is in correct, skip return value check */

Why do you mean by "in correct"?
> +       imx_scu_call_rpc(soc_ipc_handle, &msg, true);
> +
> +       soc_uid = msg.uid_high;
> +       soc_uid <<= 32;
> +       soc_uid |= msg.uid_low;
> +
> +       return sprintf(buf, "%016llX\n", soc_uid);

snprintf?

> +}
> +
> +static DEVICE_ATTR_RO(soc_uid);
> +
>  static int imx_scu_soc_id(void)
>  {
>         struct imx_sc_msg_misc_get_soc_id msg;
> @@ -102,6 +132,11 @@ static int imx_scu_soc_probe(struct platform_device *pdev)
>                 goto free_revision;
>         }
>
> +       ret = device_create_file(soc_device_to_device(soc_dev),
> +                                &dev_attr_soc_uid);
> +       if (ret)
> +               goto free_revision;
> +
>         return 0;
>
>  free_revision:
> --
> 2.7.4
>

Anson Huang June 27, 2019, 12:48 a.m. UTC | #2

Hi, Daniel

> -----Original Message-----
> From: Daniel Baluta <[e-mail]>
> Sent: Wednesday, June 26, 2019 8:42 PM
> To: Anson Huang <[e-mail]>
> Cc: Shawn Guo <[e-mail]>; Sascha Hauer
> <[e-mail]>; Pengutronix Kernel Team
> <[e-mail]>; Fabio Estevam <[e-mail]>; Aisheng
> Dong <[e-mail]>; Abel Vesa <[e-mail]>; linux-
> arm-kernel <[e-mail]>; Linux Kernel Mailing List
> <[e-mail]>; dl-linux-imx <[e-mail]>; Daniel
> Baluta <[e-mail]>
> Subject: Re: [PATCH] soc: imx-scu: Add SoC UID(unique identifier) support
> 
> On Wed, Jun 26, 2019 at 10:06 AM <[e-mail]> wrote:
> >
> > From: Anson Huang <[e-mail]>
> >
> > Add i.MX SCU SoC's UID(unique identifier) support, user can read it
> > from sysfs:
> >
> > root@imx8qxpmek:~# cat /sys/devices/soc0/soc_uid
> > 7B64280B57AC1898
> >
> > Signed-off-by: Anson Huang <[e-mail]>
> > ---
> >  drivers/soc/imx/soc-imx-scu.c | 35
> > +++++++++++++++++++++++++++++++++++
> >  1 file changed, 35 insertions(+)
> >
> > diff --git a/drivers/soc/imx/soc-imx-scu.c
> > b/drivers/soc/imx/soc-imx-scu.c index 676f612..8d322a1 100644
> > --- a/drivers/soc/imx/soc-imx-scu.c
> > +++ b/drivers/soc/imx/soc-imx-scu.c
> > @@ -27,6 +27,36 @@ struct imx_sc_msg_misc_get_soc_id {
> >         } data;
> >  } __packed;
> >
> > +struct imx_sc_msg_misc_get_soc_uid {
> > +       struct imx_sc_rpc_msg hdr;
> > +       u32 uid_low;
> > +       u32 uid_high;
> > +} __packed;
> > +
> > +static ssize_t soc_uid_show(struct device *dev,
> > +                           struct device_attribute *attr, char *buf)
> > +{
> > +       struct imx_sc_msg_misc_get_soc_uid msg;
> > +       struct imx_sc_rpc_msg *hdr = &msg.hdr;
> > +       u64 soc_uid;
> > +
> > +       hdr->ver = IMX_SC_RPC_VERSION;
> > +       hdr->svc = IMX_SC_RPC_SVC_MISC;
> > +       hdr->func = IMX_SC_MISC_FUNC_UNIQUE_ID;
> > +       hdr->size = 1;
> > +
> > +       /* the return value of SCU FW is in correct, skip return value
> > + check */
> 
> Why do you mean by "in correct"?

I made a mistake, it should be "incorrect", the existing SCFW of this API returns
an error value even this API is successfully called, to make it work with current
SCFW, I have to skip the return value check for this API for now. Will send V2 patch
to fix this typo.

> > +       imx_scu_call_rpc(soc_ipc_handle, &msg, true);
> > +
> > +       soc_uid = msg.uid_high;
> > +       soc_uid <<= 32;
> > +       soc_uid |= msg.uid_low;
> > +
> > +       return sprintf(buf, "%016llX\n", soc_uid);
> 
> snprintf?

The snprintf is to avoid buffer overflow, which in this case, I don't know the size
of "buf", and the value(u64) to be printed is with fixed length of 64, so I think
sprint is just OK.

Anson.
> 
> > +}
> > +
> > +static DEVICE_ATTR_RO(soc_uid);
> > +
> >  static int imx_scu_soc_id(void)
> >  {
> >         struct imx_sc_msg_misc_get_soc_id msg; @@ -102,6 +132,11 @@
> > static int imx_scu_soc_probe(struct platform_device *pdev)
> >                 goto free_revision;
> >         }
> >
> > +       ret = device_create_file(soc_device_to_device(soc_dev),
> > +                                &dev_attr_soc_uid);
> > +       if (ret)
> > +               goto free_revision;
> > +
> >         return 0;
> >
> >  free_revision:
> > --
> > 2.7.4
> >

Daniel Baluta June 27, 2019, 6:43 a.m. UTC | #3

On Thu, Jun 27, 2019 at 3:48 AM Anson Huang <[e-mail]> wrote:
>
> Hi, Daniel
>
> > -----Original Message-----
> > From: Daniel Baluta <[e-mail]>
> > Sent: Wednesday, June 26, 2019 8:42 PM
> > To: Anson Huang <[e-mail]>
> > Cc: Shawn Guo <[e-mail]>; Sascha Hauer
> > <[e-mail]>; Pengutronix Kernel Team
> > <[e-mail]>; Fabio Estevam <[e-mail]>; Aisheng
> > Dong <[e-mail]>; Abel Vesa <[e-mail]>; linux-
> > arm-kernel <[e-mail]>; Linux Kernel Mailing List
> > <[e-mail]>; dl-linux-imx <[e-mail]>; Daniel
> > Baluta <[e-mail]>
> > Subject: Re: [PATCH] soc: imx-scu: Add SoC UID(unique identifier) support
> >
> > On Wed, Jun 26, 2019 at 10:06 AM <[e-mail]> wrote:
> > >
> > > From: Anson Huang <[e-mail]>
> > >
> > > Add i.MX SCU SoC's UID(unique identifier) support, user can read it
> > > from sysfs:
> > >
> > > root@imx8qxpmek:~# cat /sys/devices/soc0/soc_uid
> > > 7B64280B57AC1898
> > >
> > > Signed-off-by: Anson Huang <[e-mail]>
> > > ---
> > >  drivers/soc/imx/soc-imx-scu.c | 35
> > > +++++++++++++++++++++++++++++++++++
> > >  1 file changed, 35 insertions(+)
> > >
> > > diff --git a/drivers/soc/imx/soc-imx-scu.c
> > > b/drivers/soc/imx/soc-imx-scu.c index 676f612..8d322a1 100644
> > > --- a/drivers/soc/imx/soc-imx-scu.c
> > > +++ b/drivers/soc/imx/soc-imx-scu.c
> > > @@ -27,6 +27,36 @@ struct imx_sc_msg_misc_get_soc_id {
> > >         } data;
> > >  } __packed;
> > >
> > > +struct imx_sc_msg_misc_get_soc_uid {
> > > +       struct imx_sc_rpc_msg hdr;
> > > +       u32 uid_low;
> > > +       u32 uid_high;
> > > +} __packed;
> > > +
> > > +static ssize_t soc_uid_show(struct device *dev,
> > > +                           struct device_attribute *attr, char *buf)
> > > +{
> > > +       struct imx_sc_msg_misc_get_soc_uid msg;
> > > +       struct imx_sc_rpc_msg *hdr = &msg.hdr;
> > > +       u64 soc_uid;
> > > +
> > > +       hdr->ver = IMX_SC_RPC_VERSION;
> > > +       hdr->svc = IMX_SC_RPC_SVC_MISC;
> > > +       hdr->func = IMX_SC_MISC_FUNC_UNIQUE_ID;
> > > +       hdr->size = 1;
> > > +
> > > +       /* the return value of SCU FW is in correct, skip return value
> > > + check */
> >
> > Why do you mean by "in correct"?
>
> I made a mistake, it should be "incorrect", the existing SCFW of this API returns
> an error value even this API is successfully called, to make it work with current
> SCFW, I have to skip the return value check for this API for now. Will send V2 patch
> to fix this typo.

Thanks Anson! It makes sense now. It is a little bit sad though because we won't
know when there is a "real" error :).

Lets update the comment to be more specific:

/* SCFW FW API always returns an error even the function is
successfully executed, so skip returned value */


> > > +       imx_scu_call_rpc(soc_ipc_handle, &msg, true);
> > > +
> > > +       soc_uid = msg.uid_high;
> > > +       soc_uid <<= 32;
> > > +       soc_uid |= msg.uid_low;
> > > +
> > > +       return sprintf(buf, "%016llX\n", soc_uid);
> >
> > snprintf?
>
> The snprintf is to avoid buffer overflow, which in this case, I don't know the size
> of "buf", and the value(u64) to be printed is with fixed length of 64, so I think
> sprint is just OK.

Ok.

Anson Huang June 27, 2019, 7:01 a.m. UTC | #4

Hi, Daniel

> -----Original Message-----
> From: Daniel Baluta <[e-mail]>
> Sent: Thursday, June 27, 2019 2:44 PM
> To: Anson Huang <[e-mail]>
> Cc: Shawn Guo <[e-mail]>; Sascha Hauer
> <[e-mail]>; Pengutronix Kernel Team
> <[e-mail]>; Fabio Estevam <[e-mail]>; Aisheng
> Dong <[e-mail]>; Abel Vesa <[e-mail]>; linux-
> arm-kernel <[e-mail]>; Linux Kernel Mailing List
> <[e-mail]>; dl-linux-imx <[e-mail]>; Daniel
> Baluta <[e-mail]>
> Subject: Re: [PATCH] soc: imx-scu: Add SoC UID(unique identifier) support
> 
> On Thu, Jun 27, 2019 at 3:48 AM Anson Huang <[e-mail]>
> wrote:
> >
> > Hi, Daniel
> >
> > > -----Original Message-----
> > > From: Daniel Baluta <[e-mail]>
> > > Sent: Wednesday, June 26, 2019 8:42 PM
> > > To: Anson Huang <[e-mail]>
> > > Cc: Shawn Guo <[e-mail]>; Sascha Hauer
> > > <[e-mail]>; Pengutronix Kernel Team
> > > <[e-mail]>; Fabio Estevam <[e-mail]>;
> Aisheng
> > > Dong <[e-mail]>; Abel Vesa <[e-mail]>; linux-
> > > arm-kernel <[e-mail]>; Linux Kernel
> > > Mailing List <[e-mail]>; dl-linux-imx
> > > <[e-mail]>; Daniel Baluta <[e-mail]>
> > > Subject: Re: [PATCH] soc: imx-scu: Add SoC UID(unique identifier)
> > > support
> > >
> > > On Wed, Jun 26, 2019 at 10:06 AM <[e-mail]> wrote:
> > > >
> > > > From: Anson Huang <[e-mail]>
> > > >
> > > > Add i.MX SCU SoC's UID(unique identifier) support, user can read
> > > > it from sysfs:
> > > >
> > > > root@imx8qxpmek:~# cat /sys/devices/soc0/soc_uid
> > > > 7B64280B57AC1898
> > > >
> > > > Signed-off-by: Anson Huang <[e-mail]>
> > > > ---
> > > >  drivers/soc/imx/soc-imx-scu.c | 35
> > > > +++++++++++++++++++++++++++++++++++
> > > >  1 file changed, 35 insertions(+)
> > > >
> > > > diff --git a/drivers/soc/imx/soc-imx-scu.c
> > > > b/drivers/soc/imx/soc-imx-scu.c index 676f612..8d322a1 100644
> > > > --- a/drivers/soc/imx/soc-imx-scu.c
> > > > +++ b/drivers/soc/imx/soc-imx-scu.c
> > > > @@ -27,6 +27,36 @@ struct imx_sc_msg_misc_get_soc_id {
> > > >         } data;
> > > >  } __packed;
> > > >
> > > > +struct imx_sc_msg_misc_get_soc_uid {
> > > > +       struct imx_sc_rpc_msg hdr;
> > > > +       u32 uid_low;
> > > > +       u32 uid_high;
> > > > +} __packed;
> > > > +
> > > > +static ssize_t soc_uid_show(struct device *dev,
> > > > +                           struct device_attribute *attr, char
> > > > +*buf) {
> > > > +       struct imx_sc_msg_misc_get_soc_uid msg;
> > > > +       struct imx_sc_rpc_msg *hdr = &msg.hdr;
> > > > +       u64 soc_uid;
> > > > +
> > > > +       hdr->ver = IMX_SC_RPC_VERSION;
> > > > +       hdr->svc = IMX_SC_RPC_SVC_MISC;
> > > > +       hdr->func = IMX_SC_MISC_FUNC_UNIQUE_ID;
> > > > +       hdr->size = 1;
> > > > +
> > > > +       /* the return value of SCU FW is in correct, skip return
> > > > + value check */
> > >
> > > Why do you mean by "in correct"?
> >
> > I made a mistake, it should be "incorrect", the existing SCFW of this
> > API returns an error value even this API is successfully called, to
> > make it work with current SCFW, I have to skip the return value check
> > for this API for now. Will send V2 patch to fix this typo.
> 
> Thanks Anson! It makes sense now. It is a little bit sad though because we
> won't know when there is a "real" error :).
> 
> Lets update the comment to be more specific:
> 
> /* SCFW FW API always returns an error even the function is successfully
> executed, so skip returned value */

OK, as for external users, the SCFW formally released has this issue, so for now
I have to skip the return value check for this API, once next SCFW release has this issue
fixed, I will add a patch to check the return value.

Thanks,
Anson.
> 
> 
> > > > +       imx_scu_call_rpc(soc_ipc_handle, &msg, true);
> > > > +
> > > > +       soc_uid = msg.uid_high;
> > > > +       soc_uid <<= 32;
> > > > +       soc_uid |= msg.uid_low;
> > > > +
> > > > +       return sprintf(buf, "%016llX\n", soc_uid);
> > >
> > > snprintf?
> >
> > The snprintf is to avoid buffer overflow, which in this case, I don't
> > know the size of "buf", and the value(u64) to be printed is with fixed
> > length of 64, so I think sprint is just OK.
> 
> Ok.

Marco Felsch July 2, 2019, 6:42 a.m. UTC | #5

Hi Anson,

On 19-06-27 07:01, Anson Huang wrote:
> Hi, Daniel
> 
> > -----Original Message-----
> > From: Daniel Baluta <[e-mail]>
> > Sent: Thursday, June 27, 2019 2:44 PM
> > To: Anson Huang <[e-mail]>
> > Cc: Shawn Guo <[e-mail]>; Sascha Hauer
> > <[e-mail]>; Pengutronix Kernel Team
> > <[e-mail]>; Fabio Estevam <[e-mail]>; Aisheng
> > Dong <[e-mail]>; Abel Vesa <[e-mail]>; linux-
> > arm-kernel <[e-mail]>; Linux Kernel Mailing List
> > <[e-mail]>; dl-linux-imx <[e-mail]>; Daniel
> > Baluta <[e-mail]>
> > Subject: Re: [PATCH] soc: imx-scu: Add SoC UID(unique identifier) support
> > 
> > On Thu, Jun 27, 2019 at 3:48 AM Anson Huang <[e-mail]>
> > wrote:
> > >
> > > Hi, Daniel
> > >
> > > > -----Original Message-----
> > > > From: Daniel Baluta <[e-mail]>
> > > > Sent: Wednesday, June 26, 2019 8:42 PM
> > > > To: Anson Huang <[e-mail]>
> > > > Cc: Shawn Guo <[e-mail]>; Sascha Hauer
> > > > <[e-mail]>; Pengutronix Kernel Team
> > > > <[e-mail]>; Fabio Estevam <[e-mail]>;
> > Aisheng
> > > > Dong <[e-mail]>; Abel Vesa <[e-mail]>; linux-
> > > > arm-kernel <[e-mail]>; Linux Kernel
> > > > Mailing List <[e-mail]>; dl-linux-imx
> > > > <[e-mail]>; Daniel Baluta <[e-mail]>
> > > > Subject: Re: [PATCH] soc: imx-scu: Add SoC UID(unique identifier)
> > > > support
> > > >
> > > > On Wed, Jun 26, 2019 at 10:06 AM <[e-mail]> wrote:
> > > > >
> > > > > From: Anson Huang <[e-mail]>
> > > > >
> > > > > Add i.MX SCU SoC's UID(unique identifier) support, user can read
> > > > > it from sysfs:
> > > > >
> > > > > root@imx8qxpmek:~# cat /sys/devices/soc0/soc_uid
> > > > > 7B64280B57AC1898
> > > > >
> > > > > Signed-off-by: Anson Huang <[e-mail]>
> > > > > ---
> > > > >  drivers/soc/imx/soc-imx-scu.c | 35
> > > > > +++++++++++++++++++++++++++++++++++
> > > > >  1 file changed, 35 insertions(+)
> > > > >
> > > > > diff --git a/drivers/soc/imx/soc-imx-scu.c
> > > > > b/drivers/soc/imx/soc-imx-scu.c index 676f612..8d322a1 100644
> > > > > --- a/drivers/soc/imx/soc-imx-scu.c
> > > > > +++ b/drivers/soc/imx/soc-imx-scu.c
> > > > > @@ -27,6 +27,36 @@ struct imx_sc_msg_misc_get_soc_id {
> > > > >         } data;
> > > > >  } __packed;
> > > > >
> > > > > +struct imx_sc_msg_misc_get_soc_uid {
> > > > > +       struct imx_sc_rpc_msg hdr;
> > > > > +       u32 uid_low;
> > > > > +       u32 uid_high;
> > > > > +} __packed;
> > > > > +
> > > > > +static ssize_t soc_uid_show(struct device *dev,
> > > > > +                           struct device_attribute *attr, char
> > > > > +*buf) {
> > > > > +       struct imx_sc_msg_misc_get_soc_uid msg;
> > > > > +       struct imx_sc_rpc_msg *hdr = &msg.hdr;
> > > > > +       u64 soc_uid;
> > > > > +
> > > > > +       hdr->ver = IMX_SC_RPC_VERSION;
> > > > > +       hdr->svc = IMX_SC_RPC_SVC_MISC;
> > > > > +       hdr->func = IMX_SC_MISC_FUNC_UNIQUE_ID;
> > > > > +       hdr->size = 1;
> > > > > +
> > > > > +       /* the return value of SCU FW is in correct, skip return
> > > > > + value check */
> > > >
> > > > Why do you mean by "in correct"?
> > >
> > > I made a mistake, it should be "incorrect", the existing SCFW of this
> > > API returns an error value even this API is successfully called, to
> > > make it work with current SCFW, I have to skip the return value check
> > > for this API for now. Will send V2 patch to fix this typo.
> > 
> > Thanks Anson! It makes sense now. It is a little bit sad though because we
> > won't know when there is a "real" error :).
> > 
> > Lets update the comment to be more specific:
> > 
> > /* SCFW FW API always returns an error even the function is successfully
> > executed, so skip returned value */
> 
> OK, as for external users, the SCFW formally released has this issue, so for now
> I have to skip the return value check for this API, once next SCFW release has this issue
> fixed, I will add a patch to check the return value.

Do you really keep track of that? Please can you add a FIXME: or TODO:
tag and add the firmware version containing that bug?

Regards,
  Marco

> Thanks,
> Anson.
> > 
> > 
> > > > > +       imx_scu_call_rpc(soc_ipc_handle, &msg, true);
> > > > > +
> > > > > +       soc_uid = msg.uid_high;
> > > > > +       soc_uid <<= 32;
> > > > > +       soc_uid |= msg.uid_low;
> > > > > +
> > > > > +       return sprintf(buf, "%016llX\n", soc_uid);
> > > >
> > > > snprintf?
> > >
> > > The snprintf is to avoid buffer overflow, which in this case, I don't
> > > know the size of "buf", and the value(u64) to be printed is with fixed
> > > length of 64, so I think sprint is just OK.
> > 
> > Ok.

Anson Huang July 2, 2019, 7:23 a.m. UTC | #6

Hi, Marco

> Hi Anson,
> 
> On 19-06-27 07:01, Anson Huang wrote:
> > Hi, Daniel
> >
> > > On Thu, Jun 27, 2019 at 3:48 AM Anson Huang <[e-mail]>
> > > wrote:
> > > >
> > > > Hi, Daniel
> > > >
> > > > > On Wed, Jun 26, 2019 at 10:06 AM <[e-mail]> wrote:
> > > > > >
> > > > > > From: Anson Huang <[e-mail]>
> > > > > >
> > > > > > Add i.MX SCU SoC's UID(unique identifier) support, user can
> > > > > > read it from sysfs:
> > > > > >
> > > > > > root@imx8qxpmek:~# cat /sys/devices/soc0/soc_uid
> > > > > > 7B64280B57AC1898
> > > > > >
> > > > > > Signed-off-by: Anson Huang <[e-mail]>
> > > > > > ---
> > > > > >  drivers/soc/imx/soc-imx-scu.c | 35
> > > > > > +++++++++++++++++++++++++++++++++++
> > > > > >  1 file changed, 35 insertions(+)
> > > > > >
> > > > > > diff --git a/drivers/soc/imx/soc-imx-scu.c
> > > > > > b/drivers/soc/imx/soc-imx-scu.c index 676f612..8d322a1 100644
> > > > > > --- a/drivers/soc/imx/soc-imx-scu.c
> > > > > > +++ b/drivers/soc/imx/soc-imx-scu.c
> > > > > > @@ -27,6 +27,36 @@ struct imx_sc_msg_misc_get_soc_id {
> > > > > >         } data;
> > > > > >  } __packed;
> > > > > >
> > > > > > +struct imx_sc_msg_misc_get_soc_uid {
> > > > > > +       struct imx_sc_rpc_msg hdr;
> > > > > > +       u32 uid_low;
> > > > > > +       u32 uid_high;
> > > > > > +} __packed;
> > > > > > +
> > > > > > +static ssize_t soc_uid_show(struct device *dev,
> > > > > > +                           struct device_attribute *attr,
> > > > > > +char
> > > > > > +*buf) {
> > > > > > +       struct imx_sc_msg_misc_get_soc_uid msg;
> > > > > > +       struct imx_sc_rpc_msg *hdr = &msg.hdr;
> > > > > > +       u64 soc_uid;
> > > > > > +
> > > > > > +       hdr->ver = IMX_SC_RPC_VERSION;
> > > > > > +       hdr->svc = IMX_SC_RPC_SVC_MISC;
> > > > > > +       hdr->func = IMX_SC_MISC_FUNC_UNIQUE_ID;
> > > > > > +       hdr->size = 1;
> > > > > > +
> > > > > > +       /* the return value of SCU FW is in correct, skip
> > > > > > + return value check */
> > > > >
> > > > > Why do you mean by "in correct"?
> > > >
> > > > I made a mistake, it should be "incorrect", the existing SCFW of
> > > > this API returns an error value even this API is successfully
> > > > called, to make it work with current SCFW, I have to skip the
> > > > return value check for this API for now. Will send V2 patch to fix this
> typo.
> > >
> > > Thanks Anson! It makes sense now. It is a little bit sad though
> > > because we won't know when there is a "real" error :).
> > >
> > > Lets update the comment to be more specific:
> > >
> > > /* SCFW FW API always returns an error even the function is
> > > successfully executed, so skip returned value */
> >
> > OK, as for external users, the SCFW formally released has this issue,
> > so for now I have to skip the return value check for this API, once
> > next SCFW release has this issue fixed, I will add a patch to check the return
> value.
> 
> Do you really keep track of that? Please can you add a FIXME: or TODO:
> tag and add the firmware version containing that bug?

Thanks for reminder, I just double checked the SCU FW code, it is actually a mistake, the SCU FW
API of sc_misc_unique_id() is actually a void function, which means it does NOT return anything.
While in our internal kernel tree, we make SCU IPC call to sc_misc_unique_id() with return value
check, and the return value is failure (-5) always. When I clean up the code for upstream, I did NOT notice it.
So the correct comment should be, this API does NOT return anything, no need to check the returned value.
I will fix the comment in next version.

void sc_misc_unique_id(sc_ipc_t ipc, uint32_t *id_l, uint32_t *id_h)

Thanks,
Anson

> 
> Regards,
>   Marco
> 
> > Thanks,
> > Anson.
> > >
> > >
> > > > > > +       imx_scu_call_rpc(soc_ipc_handle, &msg, true);
> > > > > > +
> > > > > > +       soc_uid = msg.uid_high;
> > > > > > +       soc_uid <<= 32;
> > > > > > +       soc_uid |= msg.uid_low;
> > > > > > +
> > > > > > +       return sprintf(buf, "%016llX\n", soc_uid);
> > > > >
> > > > > snprintf?
> > > >
> > > > The snprintf is to avoid buffer overflow, which in this case, I
> > > > don't know the size of "buf", and the value(u64) to be printed is
> > > > with fixed length of 64, so I think sprint is just OK.
> > >
> > > Ok.
> 
> --

Patch

diff --git a/drivers/soc/imx/soc-imx-scu.c b/drivers/soc/imx/soc-imx-scu.c
index 676f612..8d322a1 100644
--- a/drivers/soc/imx/soc-imx-scu.c
+++ b/drivers/soc/imx/soc-imx-scu.c
@@ -27,6 +27,36 @@  struct imx_sc_msg_misc_get_soc_id {
 	} data;
 } __packed;
 
+struct imx_sc_msg_misc_get_soc_uid {
+	struct imx_sc_rpc_msg hdr;
+	u32 uid_low;
+	u32 uid_high;
+} __packed;
+
+static ssize_t soc_uid_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct imx_sc_msg_misc_get_soc_uid msg;
+	struct imx_sc_rpc_msg *hdr = &msg.hdr;
+	u64 soc_uid;
+
+	hdr->ver = IMX_SC_RPC_VERSION;
+	hdr->svc = IMX_SC_RPC_SVC_MISC;
+	hdr->func = IMX_SC_MISC_FUNC_UNIQUE_ID;
+	hdr->size = 1;
+
+	/* the return value of SCU FW is in correct, skip return value check */
+	imx_scu_call_rpc(soc_ipc_handle, &msg, true);
+
+	soc_uid = msg.uid_high;
+	soc_uid <<= 32;
+	soc_uid |= msg.uid_low;
+
+	return sprintf(buf, "%016llX\n", soc_uid);
+}
+
+static DEVICE_ATTR_RO(soc_uid);
+
 static int imx_scu_soc_id(void)
 {
 	struct imx_sc_msg_misc_get_soc_id msg;
@@ -102,6 +132,11 @@  static int imx_scu_soc_probe(struct platform_device *pdev)
 		goto free_revision;
 	}
 
+	ret = device_create_file(soc_device_to_device(soc_dev),
+				 &dev_attr_soc_uid);
+	if (ret)
+		goto free_revision;
+
 	return 0;
 
 free_revision: