Re: [PATCH v7 5/9] misc: smpro-misc: Add Ampere's Altra SMpro misc driver

Greg Kroah-Hartman
2022-03-21T10:02:46Z

On Mon, Mar 21, 2022 at 04:46:50PM +0700, Quan Nguyen wrote:
>
>
> On 21/03/2022 15:21, Greg Kroah-Hartman wrote:
> > On Mon, Mar 21, 2022 at 03:13:51PM +0700, Quan Nguyen wrote:
> > > This commit adds driver support for accessing various information
> > > reported by Ampere's SMpro co-processor such as Boot Progress and
> > > other miscellaneous data.
> > >
> > > Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> >
> > No Documentation/ABI/ entries for your sysfs file?
> >
>
> Thank you, Greg, for a very quick review.
> I have put this file in other patch.
>
> > > +static ssize_t boot_progress_show(struct device *dev, struct device_attribute *da, char *buf)
> > > +{
> > > + struct smpro_misc *misc = dev_get_drvdata(dev);
> > > + u32 boot_progress;
> > > + u8 current_stage;
> > > + u8 boot_status;
> > > + u8 boot_stage;
> > > + u32 select;
> > > + u32 reg_lo;
> > > + u32 reg;
> > > + int ret;
> > > +
> > > + /* Read current boot stage */
> > > + ret = regmap_read(misc->regmap, BOOTSTAGE_CUR_STAGE, &reg);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + current_stage = reg & 0xff;
> > > +
> > > + /* Read the boot progress */
> > > + ret = regmap_read(misc->regmap, BOOTSTAGE_SELECT, &select);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + boot_stage = (select >> 8) & 0xff;
> > > + boot_status = select & 0xff;
> > > +
> > > + if (boot_stage > current_stage)
> > > + return -EINVAL;
> > > +
> > > + ret = regmap_read(misc->regmap, BOOTSTAGE_STATUS_LO, &reg_lo);
> > > + if (!ret)
> > > + ret = regmap_read(misc->regmap, BOOTSTAGE_STATUS_HI, &reg);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + boot_progress = swab16(reg) << 16 | swab16(reg_lo);
> > > +
> > > + /* Tell firmware to provide next boot stage next time */
> > > + if (boot_stage < current_stage) {
> > > + ret = regmap_write(misc->regmap, BOOTSTAGE_SELECT, ((select & 0xff00) | 0x1));
> > > + if (ret)
> > > + return ret;
> > > + }
> > > +
> > > + return snprintf(buf, PAGE_SIZE, "0x%02x 0x%02x 0x%08x\n",
> > > + boot_stage, boot_status, boot_progress);
> >
> > sysfs_emit() please.
> >
> Thanks, Greg.
>
> Will switch to sysfs_emit() in my next version.
>
> > Also, this is 3 different things, put all of these in different sysfs
> > files.
> >
> > thanks,
> >
> > greg k-h
>
> Actually, no. It is single value of boot stage.

You are displaying 3 things in a single line, those are 3 different
things.

> Let me explain:
> The boot progress consists of three things together: boot_stage, boot_status
> and boot_progress and they have no meaning if reported them as three
> separate values:
> + boot_stage is to indicate the boot stage
> + boot_status is to report the result of that boot_stage: started, complete
> or error.
> + boot_progress is to report more extra information for the stage other than
> the boot_stage/boot_status.

Why are these just not 3 different files? They describe three different
things, please do not EVER force userspace to parse a sysfs file other
than a single value.

thanks,

greg k-h