Re: [PATCH] OMAP3 PM export chip IDCODE, Production ID and Die ID

[Tony Lindgren <tony@atomide.com>]

* Kevin Hilman <khilman@deeprootsystems.com> [091013 12:09]:
> "Peter 'p2' De Schrijver" <peter.de-schrijver@nokia.com> writes:
> 
> > From: De-Schrijver Peter (Nokia-D/Helsinki) <Peter.De-Schrijver@nokia.com>
> >
> > This patch exports the OMAP3 IDCODE, Production ID and Die ID to userspace via
> > sysfs. This can be used to track down silicon specific issues. The info is
> > exported via sysfs because it should be possible to include this in corematic
> > dumps.
> >
> > Signed-off-by: Peter 'p2' De Schrijver <peter.de-schrijver@nokia.com>
> 
> Please export these via debugfs. 

I don't think we want to export unique chip identifiers by default.

Please search "CPU serial number disabled" for some earlier handling
of things like these for x86, and see function
squash_the_stupid_serial_number(struct cpuinfo_x86 *c) in
arch/x86/kernel/cpu/common.c :)

Regards,

Tony

> 
> Kevin
> 
> > ---
> >  arch/arm/mach-omap2/id.c |   36 ++++++++++++++++++++++++++++++++++++
> >  1 files changed, 36 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/arm/mach-omap2/id.c b/arch/arm/mach-omap2/id.c
> > index 2c5e0a3..97670e2 100644
> > --- a/arch/arm/mach-omap2/id.c
> > +++ b/arch/arm/mach-omap2/id.c
> > @@ -70,6 +70,10 @@ EXPORT_SYMBOL(omap_type);
> >  /*----------------------------------------------------------------------------*/
> >  
> >  #define OMAP_TAP_IDCODE		0x0204
> > +#define OMAP_TAP_PROD_ID_0      0x0208
> > +#define OMAP_TAP_PROD_ID_1      0x020c
> > +#define OMAP_TAP_PROD_ID_2      0x0210
> > +#define OMAP_TAP_PROD_ID_3      0x0214
> >  #define OMAP_TAP_DIE_ID_0	0x0218
> >  #define OMAP_TAP_DIE_ID_1	0x021C
> >  #define OMAP_TAP_DIE_ID_2	0x0220
> > @@ -77,6 +81,10 @@ EXPORT_SYMBOL(omap_type);
> >  
> >  #define read_tap_reg(reg)	__raw_readl(tap_base  + (reg))
> >  
> > +static ssize_t idcode_show(struct kobject *, struct kobj_attribute *, char *);
> > +static struct kobj_attribute idcode_attr = __ATTR(idcode, 0444, idcode_show,
> > +							NULL);
> > +
> >  struct omap_id {
> >  	u16	hawkeye;	/* Silicon type (Hawkeye id) */
> >  	u8	dev;		/* Device type from production_id reg */
> > @@ -96,6 +104,23 @@ static struct omap_id omap_ids[] __initdata = {
> >  static void __iomem *tap_base;
> >  static u16 tap_prod_id;
> >  
> > +static ssize_t idcode_show(struct kobject *kobj, struct kobj_attribute *attr,
> > +				char *buf)
> > +{
> > +	return sprintf(buf, "IDCODE: %08x\nProduction ID: %08x %08x %08x %08x\n"
> > +				"Die ID: %08x %08x %08x %08x\n",
> > +			read_tap_reg(OMAP_TAP_IDCODE),
> > +			read_tap_reg(OMAP_TAP_PROD_ID_0),
> > +			read_tap_reg(OMAP_TAP_PROD_ID_1),
> > +			read_tap_reg(OMAP_TAP_PROD_ID_2),
> > +			read_tap_reg(OMAP_TAP_PROD_ID_3),
> > +			read_tap_reg(OMAP_TAP_DIE_ID_0),
> > +			read_tap_reg(OMAP_TAP_DIE_ID_1),
> > +			read_tap_reg(OMAP_TAP_DIE_ID_2),
> > +			read_tap_reg(OMAP_TAP_DIE_ID_3));
> > +
> > +}
> > +
> >  void __init omap24xx_check_revision(void)
> >  {
> >  	int i, j;
> > @@ -259,3 +284,14 @@ void __init omap2_set_globals_tap(struct omap_globals *omap2_globals)
> >  	else
> >  		tap_prod_id = 0x0208;
> >  }
> > +
> > +void __init export_omapid(void)
> > +{
> > +	int error;
> > +
> > +	error = sysfs_create_file(power_kobj, &idcode_attr.attr);
> > +	if (error)
> > +		printk(KERN_ERR "sysfs_create_file failed: %d\n", error);
> > +}
> > +
> > +late_initcall(export_omapid);
> > -- 
> > 1.6.2.4
> >
> > --
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