Re: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping failure

[sathyanarayanan kuppuswamy]

Hi Rajneesh,


On 03/17/2017 04:43 AM, Rajneesh Bhardwaj wrote:
> On Thu, Mar 16, 2017 at 05:41:35PM -0700, Kuppuswamy Sathyanarayanan wrote:
> > Currently, iTCO watchdog driver uses memory map to access
> > PMC_CFG GCR register. But the entire GCR address space is
> > already mapped in intel_scu_ipc driver. So remapping the
> intel_pmc_ipc driver.
Will fix it in next series.
> > GCR register in this driver causes the mem request failure in
> > iTCO_wdt probe function. This patch fixes this issue by
> > using PMC GCR read/write API's to access PMC_CFG register.
> >
> > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> > ---
> >   drivers/watchdog/iTCO_wdt.c | 31 +++++++------------------------
> >   1 file changed, 7 insertions(+), 24 deletions(-)
> >
> > diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
> > index 3d0abc0..31abfc5 100644
> > --- a/drivers/watchdog/iTCO_wdt.c
> > +++ b/drivers/watchdog/iTCO_wdt.c
> > @@ -68,6 +68,8 @@
> >   #include <linux/io.h>			/* For inb/outb/... */
> >   #include <linux/platform_data/itco_wdt.h>
> >   
> > +#include <asm/intel_pmc_ipc.h>
> > +
> >   #include "iTCO_vendor.h"
> >   
> >   /* Address definitions for the TCO */
> > @@ -94,12 +96,6 @@ struct iTCO_wdt_private {
> >   	unsigned int iTCO_version;
> >   	struct resource *tco_res;
> >   	struct resource *smi_res;
> > -	/*
> > -	 * NO_REBOOT flag is Memory-Mapped GCS register bit 5 (TCO version 2),
> > -	 * or memory-mapped PMC register bit 4 (TCO version 3).
> > -	 */
> Better to retain this comment elsewhere.
no_reboot_bit() function might be better place for this comment.
> > -	struct resource *gcs_pmc_res;
> > -	unsigned long __iomem *gcs_pmc;
> >   	/* the lock for io operations */
> >   	spinlock_t io_lock;
> >   	/* the PCI-device */
> > @@ -176,9 +172,9 @@ static void iTCO_wdt_set_NO_REBOOT_bit(struct iTCO_wdt_private *p)
> >   
> >   	/* Set the NO_REBOOT bit: this disables reboots */
> >   	if (p->iTCO_version >= 2) {
> > -		val32 = readl(p->gcs_pmc);
> > +		val32 = intel_pmc_gcr_read(PMC_GCR_PMC_CFG_REG);
> better to have protection and error handling, discussed in v2, 2/4.
>
> compiled and tested this on APL and i see iTCO_WDT driver loads fine. Since
> it impacts core WDT functionality, need to be thoroughly tested on various
> platforms.
I have tested it in Joule and it works fine. it would be nice if some 
one can verify it in non-atom platforms.
> > --
> > 2.7.4

--
Sathyanarayanan Kuppuswamy
Android kernel developer