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

Shobhit Kumar
2015-02-09T11:16:10Z

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 ?

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