Hi Ingo and Thomas,
One question inside on location.
On Sat, 2015-05-02 at 08:00 +0200, Ingo Molnar wrote:
> * Srinivas Pandruvada <srinivas.pandruv...@linux.intel.com> wrote:
> 
> > The patch adds a debug driver, which dumps the power states
> > of all the North complex (NC) devices. This debug interface is
> > useful to figure out the NC IPs which blocks the S0ix
> > transitions on the platform. This is extremely useful during
> > enabling PM on customer platforms and derivatives.
> 
> Looks useful.
> 
> > This submission not a complete rewrite from the original
> > submission from Kumar P, Mahesh <mahesh.kumar.p.intel.com>.
> > https://lkml.org/lkml/2014/11/5/367
> 
> This sentence does not parse. Did you mean 'is a complete rewrite'?
> 
> > +config PUNIT_ATOM_DEBUG
> > +   tristate "ATOM Punit debug driver"
> > +   depends on DEBUG_FS
> > +   select IOSF_MBI
> > +   ---help---
> > +     This is a debug driver, which gets the power states
> > +     of all Punit North Complex devices.The power states of
> > +     each IP is exposed as part of the debugfs interface.
> 
> What is an 'IP'?
> 
> Also:
> 
>       s/devices.The
>        /devices. The
> 
> > +
> >  endmenu
> > diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
> > index cdb1b70..2ecbd55 100644
> > --- a/arch/x86/kernel/Makefile
> > +++ b/arch/x86/kernel/Makefile
> > @@ -110,6 +110,7 @@ obj-$(CONFIG_PERF_EVENTS)               += perf_regs.o
> >  obj-$(CONFIG_TRACING)                      += tracepoint.o
> >  obj-$(CONFIG_IOSF_MBI)                     += iosf_mbi.o
> >  obj-$(CONFIG_PMC_ATOM)                     += pmc_atom.o
> > +obj-$(CONFIG_PUNIT_ATOM_DEBUG)             += punit_atom_debug.o
> >  
> >  ###
> >  # 64 bit specific files
> > diff --git a/arch/x86/kernel/punit_atom_debug.c 
> > b/arch/x86/kernel/punit_atom_debug.c
> 
> Please put this somewhere suitable in arch/x86/platform/.
I moved this to arch/x86/platform/intel-mid, but punit is much more part
of common core atom soc platform. This can have both mobile and PC like
platform. What about creating arch/x86/platform/intel-atom-common, and
add there?

Thanks,
Srinivas
> 
> > +/*
> > + * Intel SOC Punit device state debug driver
> > + * Copyright (c) 2015, Intel Corporation.
> 
> Would be nice to add a blurb about what 'Intel SOC Punit' systems are. 
> There doesn't seem to be anything in the kernel source about it, so 
> you have a golden opportunity here.
> 
> > +#define PUNIT_PORT         0x04
> > +#define PWRGT_STATUS               0x61 /* Power gate status reg */
> > +#define VED_SS_PM0         0x32 /* Subsystem config/status Video */
> > +#define ISP_SS_PM0         0x39 /* Subsystem config/status ISP */
> > +#define MIO_SS_PM          0x3B /* Subsystem config/status MIO */
> > +#define SSS_SHIFT          24
> > +#define RENDER_POS         0
> > +#define MEDIA_POS          2
> > +#define VLV_DISPLAY_POS            6
> > +#define CHT_DSP_SSS                0x36 /* Subsystem config/status DSP */
> > +#define CHT_DSP_SSS_POS            16
> 
> All the magic constants need some explanation for humans, not just 
> some.
> 
> > +static const struct punit_device punit_device_byt[] = {
> > +   { "GFX RENDER", PWRGT_STATUS, RENDER_POS },
> > +   { "GFX MEDIA", PWRGT_STATUS, MEDIA_POS },
> > +   { "DISPLAY", PWRGT_STATUS, VLV_DISPLAY_POS },
> > +   { "VED", VED_SS_PM0, SSS_SHIFT},
> > +   { "ISP", ISP_SS_PM0, SSS_SHIFT},
> > +   { "MIO", MIO_SS_PM, SSS_SHIFT},
> > +   { NULL}
> > +};
> > +
> > +static const struct punit_device punit_device_cht[] = {
> > +   { "GFX RENDER", PWRGT_STATUS, RENDER_POS },
> > +   { "GFX MEDIA", PWRGT_STATUS, MEDIA_POS },
> > +   { "DSP", CHT_DSP_SSS,  CHT_DSP_SSS_POS },
> > +   { "VED", VED_SS_PM0, SSS_SHIFT},
> > +   { "ISP", ISP_SS_PM0, SSS_SHIFT},
> > +   { "MIO", MIO_SS_PM, SSS_SHIFT},
> > +   { NULL}
> > +};
> 
> Please align such initialization tables vertically, like you did here:
> 
> > +static const struct file_operations punit_dev_state_ops = {
> > +   .open           = punit_dev_state_open,
> > +   .read           = seq_read,
> > +   .llseek         = seq_lseek,
> > +   .release        = single_release,
> > +};
> 
> 
> > +   punit_dbg_file = debugfs_create_dir("punit_atom", NULL);
> > +   if (!punit_dbg_file)
> > +           return -ENXIO;
> > +
> > +   dev_state = debugfs_create_file("dev_state", S_IFREG | S_IRUGO,
> > +                                    punit_dbg_file, NULL,
> > +                                    &punit_dev_state_ops);
> 
> So why isn't something that is declaradly a power state dump, called 
> "power_state" or "dev_power_state"?
> 
> > +MODULE_AUTHOR("Kumar P, Mahesh <mahesh.kumar.p.intel.com>");
> > +MODULE_DESCRIPTION("Driver for Punit devices states debugging");
> > +MODULE_LICENSE("GPL v2");
> 
> Btw., you can have multiple MODULE_AUTHOR() lines, so you can credit
> yourself as well. Take a look at drivers/net/wireless/at76c50x-usb.c's 
> MODULE_AUTHOR() for grins.
> 
> Thanks,
> 
>       Ingo


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