Re: [PATCH] drm/i915: Correct the IOSF Dev_FN field for IOSF transfers

Jani Nikula
2015-02-09T12:26:54Z

On Mon, 09 Feb 2015, Shobhit Kumar <shobhit.kumar@linux.intel.com> wrote:
> On 02/05/2015 10:44 PM, Ville Syrjälä wrote:
>> On Thu, Feb 05, 2015 at 05:10:56PM +0530, Shobhit Kumar wrote:
>>> As per the specififcation, the SB_DevFn is the PCI_DEVFN of the target
>>> device and not the source. So PCI_DEVFN(2,0) is not correct. Further the
>>> port ID should be enough to identify devices unless they are MFD. The
>>> SB_DevFn was intended to remove ambiguity in case of these MFD devices.
>>>
>>> For non MFD devices the recommendation for the target device IP was to
>>> ignore these fields, but not all of them followed the recommendation.
>>> Some like CCK ignore these fields and hence PCI_DEVFN(2, 0) works and so
>>> does PCI_DEVFN(0, 0) as it works for DPIO. The issue came to light because
>>> of GPIONC which was not getting programmed correctly with PCI_DEVFN(2, 0).
>>> It turned out that this did not follow the recommendation and expected 0
>>> in this field.
>>>
>>> In general the recommendation is to use SB_DevFn as PCI_DEVFN(0, 0) for
>>> all devices except target PCI devices.
>>>
>>> Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
>>
>> Yep, confirmed on my BYT that GPIONC doesn't like the devfn 2.0. On BSW
>> GPIONC seems to have become more relaxed and accepts devfn 2.0 as well.
>>
>> I also tried to poke at all the other sideband units we care about and
>> they appear to work just as well with 2.0 and 0.0. But being consistent
>> seems like a good idea, so 0.0 it is for everyone.
>>
>> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Thanks Ville. Daniel this needs more testing/reviews to merge ?

Pushed to drm-intel-next-fixes with cc: stable, thanks for the patch and
review.

BR,
Jani.

>
> Regards
> Shobhit
>
>>
>>> ---
>>> drivers/gpu/drm/i915/intel_sideband.c | 26 +++++++++++++-------------
>>> 1 file changed, 13 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_sideband.c b/drivers/gpu/drm/i915/intel_sideband.c
>>> index 01d841e..731b10a 100644
>>> --- a/drivers/gpu/drm/i915/intel_sideband.c
>>> +++ b/drivers/gpu/drm/i915/intel_sideband.c
>>> @@ -82,7 +82,7 @@ u32 vlv_punit_read(struct drm_i915_private *dev_priv, u8 addr)
>>> WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
>>>
>>> mutex_lock(&dev_priv->dpio_lock);
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_PUNIT,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_PUNIT,
>>> SB_CRRDDA_NP, addr, &val);
>>> mutex_unlock(&dev_priv->dpio_lock);
>>>
>>> @@ -94,7 +94,7 @@ void vlv_punit_write(struct drm_i915_private *dev_priv, u8 addr, u32 val)
>>> WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
>>>
>>> mutex_lock(&dev_priv->dpio_lock);
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_PUNIT,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_PUNIT,
>>> SB_CRWRDA_NP, addr, &val);
>>> mutex_unlock(&dev_priv->dpio_lock);
>>> }
>>> @@ -103,7 +103,7 @@ u32 vlv_bunit_read(struct drm_i915_private *dev_priv, u32 reg)
>>> {
>>> u32 val = 0;
>>>
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_BUNIT,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_BUNIT,
>>> SB_CRRDDA_NP, reg, &val);
>>>
>>> return val;
>>> @@ -111,7 +111,7 @@ u32 vlv_bunit_read(struct drm_i915_private *dev_priv, u32 reg)
>>>
>>> void vlv_bunit_write(struct drm_i915_private *dev_priv, u32 reg, u32 val)
>>> {
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_BUNIT,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_BUNIT,
>>> SB_CRWRDA_NP, reg, &val);
>>> }
>>>
>>> @@ -122,7 +122,7 @@ u32 vlv_nc_read(struct drm_i915_private *dev_priv, u8 addr)
>>> WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
>>>
>>> mutex_lock(&dev_priv->dpio_lock);
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_NC,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_NC,
>>> SB_CRRDDA_NP, addr, &val);
>>> mutex_unlock(&dev_priv->dpio_lock);
>>>
>>> @@ -132,56 +132,56 @@ u32 vlv_nc_read(struct drm_i915_private *dev_priv, u8 addr)
>>> u32 vlv_gpio_nc_read(struct drm_i915_private *dev_priv, u32 reg)
>>> {
>>> u32 val = 0;
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_GPIO_NC,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_GPIO_NC,
>>> SB_CRRDDA_NP, reg, &val);
>>> return val;
>>> }
>>>
>>> void vlv_gpio_nc_write(struct drm_i915_private *dev_priv, u32 reg, u32 val)
>>> {
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_GPIO_NC,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_GPIO_NC,
>>> SB_CRWRDA_NP, reg, &val);
>>> }
>>>
>>> u32 vlv_cck_read(struct drm_i915_private *dev_priv, u32 reg)
>>> {
>>> u32 val = 0;
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_CCK,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_CCK,
>>> SB_CRRDDA_NP, reg, &val);
>>> return val;
>>> }
>>>
>>> void vlv_cck_write(struct drm_i915_private *dev_priv, u32 reg, u32 val)
>>> {
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_CCK,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_CCK,
>>> SB_CRWRDA_NP, reg, &val);
>>> }
>>>
>>> u32 vlv_ccu_read(struct drm_i915_private *dev_priv, u32 reg)
>>> {
>>> u32 val = 0;
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_CCU,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_CCU,
>>> SB_CRRDDA_NP, reg, &val);
>>> return val;
>>> }
>>>
>>> void vlv_ccu_write(struct drm_i915_private *dev_priv, u32 reg, u32 val)
>>> {
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_CCU,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_CCU,
>>> SB_CRWRDA_NP, reg, &val);
>>> }
>>>
>>> u32 vlv_gps_core_read(struct drm_i915_private *dev_priv, u32 reg)
>>> {
>>> u32 val = 0;
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_GPS_CORE,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_GPS_CORE,
>>> SB_CRRDDA_NP, reg, &val);
>>> return val;
>>> }
>>>
>>> void vlv_gps_core_write(struct drm_i915_private *dev_priv, u32 reg, u32 val)
>>> {
>>> - vlv_sideband_rw(dev_priv, PCI_DEVFN(2, 0), IOSF_PORT_GPS_CORE,
>>> + vlv_sideband_rw(dev_priv, PCI_DEVFN(0, 0), IOSF_PORT_GPS_CORE,
>>> SB_CRWRDA_NP, reg, &val);
>>> }
>>>
>>> --
>>> 1.9.1
>>

--
Jani Nikula, Intel Open Source Technology Center