Re: [PATCH v9 5/9] misc: smpro-misc: Add Ampere's Altra SMpro misc driver

[Quan Nguyen]

On 29/09/2022 16:55, Greg Kroah-Hartman wrote:
> On Thu, Sep 29, 2022 at 04:43:17PM +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>
> > ---
> > Changes in v9:
> >    + Update SPDX licence                                     [Greg]
> >    + Use ATTRIBUTE_GROUPS()                                  [Greg]
> >    + Use dev_groups instead of sysfs_create_group() to avoid
> >    racing issue with user space                              [Greg]
> >    + Refactor code to avoid clever encoding issue            [Quan]
> >
> > Changes in v8:
> >    + Update wording for SMPRO_MISC in Kconfig file           [Quan]
> >    + Switch to use sysfs_emit()                              [Quan]
> >
> > Changes in v7:
> >    + Fix wrong return type of *_show/store()
> >    functions                                    [kernel robot test]
> >    + Adjust patch order to remove dependence with
> >    smpro-mfd                                            [Lee Jones]
> >
> > Changes in v6:
> >    + First introduced in v6 [Quan]
> >
> >   drivers/misc/Kconfig      |  10 +++
> >   drivers/misc/Makefile     |   1 +
> >   drivers/misc/smpro-misc.c | 145 ++++++++++++++++++++++++++++++++++++++
> >   3 files changed, 156 insertions(+)
> >   create mode 100644 drivers/misc/smpro-misc.c
> >
> > diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> > index b9ceee949dab..9947b7892bd5 100644
> > --- a/drivers/misc/Kconfig
> > +++ b/drivers/misc/Kconfig
> > @@ -188,6 +188,16 @@ config SMPRO_ERRMON
> >   	  To compile this driver as a module, say M here. The driver will be
> >   	  called smpro-errmon.
> >   
> > +config SMPRO_MISC
> > +	tristate "Ampere Computing SMPro miscellaneous driver"
> > +	depends on MFD_SMPRO || COMPILE_TEST
> > +	help
> > +	  Say Y here to get support for the SMpro error miscellalenous function
> > +	  provided by Ampere Computing's Altra and Altra Max SoCs.
> > +
> > +	  To compile this driver as a module, say M here. The driver will be
> > +	  called smpro-misc.
> > +
> >   config CS5535_MFGPT
> >   	tristate "CS5535/CS5536 Geode Multi-Function General Purpose Timer (MFGPT) support"
> >   	depends on MFD_CS5535
> > diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> > index bbe24d4511a3..87b54a4a4422 100644
> > --- a/drivers/misc/Makefile
> > +++ b/drivers/misc/Makefile
> > @@ -24,6 +24,7 @@ obj-$(CONFIG_KGDB_TESTS)	+= kgdbts.o
> >   obj-$(CONFIG_SGI_XP)		+= sgi-xp/
> >   obj-$(CONFIG_SGI_GRU)		+= sgi-gru/
> >   obj-$(CONFIG_SMPRO_ERRMON)	+= smpro-errmon.o
> > +obj-$(CONFIG_SMPRO_MISC)	+= smpro-misc.o
> >   obj-$(CONFIG_CS5535_MFGPT)	+= cs5535-mfgpt.o
> >   obj-$(CONFIG_GEHC_ACHC)		+= gehc-achc.o
> >   obj-$(CONFIG_HP_ILO)		+= hpilo.o
> > diff --git a/drivers/misc/smpro-misc.c b/drivers/misc/smpro-misc.c
> > new file mode 100644
> > index 000000000000..6c427141e51b
> > --- /dev/null
> > +++ b/drivers/misc/smpro-misc.c
> > @@ -0,0 +1,145 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Ampere Computing SoC's SMpro Misc Driver
> > + *
> > + * Copyright (c) 2022, Ampere Computing LLC
> > + */
> > +#include <linux/mod_devicetable.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +
> > +/* Boot Stage/Progress Registers */
> > +#define BOOTSTAGE	0xB0
> > +#define BOOTSTAGE_LO	0xB1
> > +#define CUR_BOOTSTAGE	0xB2
> > +#define BOOTSTAGE_HI	0xB3
> > +
> > +/* SOC State Registers */
> > +#define SOC_POWER_LIMIT		0xE5
> > +
> > +struct smpro_misc {
> > +	struct regmap *regmap;
> > +};
> > +
> > +static ssize_t boot_progress_show(struct device *dev, struct device_attribute *da, char *buf)
> > +{
> > +	struct smpro_misc *misc = dev_get_drvdata(dev);
> > +	u16 boot_progress[3] = { 0 };
> > +	u32 bootstage;
> > +	u8 boot_stage;
> > +	u8 cur_stage;
> > +	u32 reg_lo;
> > +	u32 reg;
> > +	int ret;
> > +
> > +	/* Read current boot stage */
> > +	ret = regmap_read(misc->regmap, CUR_BOOTSTAGE, &reg);
> > +	if (ret)
> > +		return ret;
> > +
> > +	cur_stage = reg & 0xff;
> > +
> > +	ret = regmap_read(misc->regmap, BOOTSTAGE, &bootstage);
> > +	if (ret)
> > +		return ret;
> > +
> > +	boot_stage = (bootstage >> 8) & 0xff;
> > +
> > +	if (boot_stage > cur_stage)
> > +		return -EINVAL;
> > +
> > +	ret = regmap_read(misc->regmap,	BOOTSTAGE_LO, &reg_lo);
> > +	if (!ret)
> > +		ret = regmap_read(misc->regmap, BOOTSTAGE_HI, &reg);
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* Firmware to report new boot stage next time */
> > +	if (boot_stage < cur_stage) {
> > +		ret = regmap_write(misc->regmap, BOOTSTAGE, ((bootstage & 0xff00) | 0x1));
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	boot_progress[0] = bootstage;
> > +	boot_progress[1] = swab16(reg);
> > +	boot_progress[2] = swab16(reg_lo);
> > +
> > +	return sysfs_emit(buf, "%*phN\n", (int)sizeof(boot_progress), boot_progress);
> > +}
>
> Again, please put the Documentation/ABI/ entries in this commit so that
> we can verify they are all correct.  Putting them at the end of the
> series makes it pretty impossible to review.  Would you want to have to
> match them all up the way you sent them?
Will do in next version.

Thanks,
- Quan