On Thu, Jun 27, 2019 at 3:48 AM Anson Huang <[email protected]> wrote: > > Hi, Daniel > > > -----Original Message----- > > From: Daniel Baluta <[email protected]> > > Sent: Wednesday, June 26, 2019 8:42 PM > > To: Anson Huang <[email protected]> > > Cc: Shawn Guo <[email protected]>; Sascha Hauer > > <[email protected]>; Pengutronix Kernel Team > > <[email protected]>; Fabio Estevam <[email protected]>; Aisheng > > Dong <[email protected]>; Abel Vesa <[email protected]>; linux- > > arm-kernel <[email protected]>; Linux Kernel Mailing List > > <[email protected]>; dl-linux-imx <[email protected]>; Daniel > > Baluta <[email protected]> > > Subject: Re: [PATCH] soc: imx-scu: Add SoC UID(unique identifier) support > > > > On Wed, Jun 26, 2019 at 10:06 AM <[email protected]> wrote: > > > > > > From: Anson Huang <[email protected]> > > > > > > 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 <[email protected]> > > > --- > > > 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.
