lkml.org 
[lkml]   [2017]   [Mar]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v2 3/4] watchdog: iTCO_wdt: Fix PMC GCR memory mapping failure
    On Fri, Mar 17, 2017 at 10:24:35AM -0700, sathyanarayanan kuppuswamy wrote:
    >
    >
    > On 03/17/2017 06:40 AM, Guenter Roeck wrote:
    > >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.
    > >>
    > >>>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@linux.intel.com>
    > >>>---
    > >>> 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.
    > >>
    > >>>- 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 don't think I (or the watchdog mailing list) was copied on the original
    > >patch.
    > Sorry. Its my mistake. I will fix it in next series update.
    > >Major immediate concern is that this introduces a dependency on external
    > >code.
    > >The pmc_ipc driver's Kconfig entry states "This is not needed for PC-type
    > >machines". I don't know where the function is introduced, but I hope this
    > >change
    > >does not require the pmc_ipc code to be present on such machines for the
    > >watchdog
    > >to work. It would be bad if it does. If it doesn't, it appears that the
    > >function
    > >should not be declared in asm/intel_pmc_ipc.h.
    > It should not create any compile time dependency with INTEL_PMC_IPC config
    > option. If INTEL_PMC_IPC_CONFIG is disabled, we use
    > empty definitions for these calls defined in asm/intel_pmc_ipc.h
    >

    So the watchdog driver would get an error if CONFIG_INTEL_PMC_IPC
    is not defined ? And that is supposed to be acceptable ?

    > But iTCO_wdt driver already has runtime dependency with INTEL_PMIC_IPC if
    > its version iTCO_version >= 2.
    >
    Unless I am missing something, there is no explicit dependency. AFAICS
    the watchdog driver works just fine if INTEL_PMIC_IPC is not enabled,
    and/or if it is built as module and the module is not loaded.

    Maybe you mean that the watchdog driver doesn't load if the INTEL_PMIC_IPC
    driver is loaded. That would be a bug, not a dependency.

    Guenter

    \
     
     \ /
      Last update: 2017-03-17 18:53    [W:3.803 / U:0.292 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site