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

[Quan Nguyen <quan@xxxxxxxxxxxxxxxxxxxxxx>]

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@xxxxxxxxxxxxxxxxxxxxxx>
>
> 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.

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.

There is more information in the Documentation/ABI/testing sysfs patch.

- Quan