Subject: Re: [PATCH 4/4] net: stmmac: add MSI support for Intel Quark X1000

From: Bryan O'Donoghue <[email-masked]>
Date: Wed, 01 Oct 2014 12:29:04 +0100

> Hi Guys,
>
> Just gently ping for the discussion to carry on before forgetting the context.
> Anyone have any better idea or comments or concern to this topic?
> Hope the above explanation clear out your doubt.
>
>
> Regards,
> Wilson

Hi Wilson.

Seeing you post now on the PCI emumeration suggestion from Dave Miller I see

I wasn't copied on this https://lkml.org/lkml/2014/8/27/190 thread so 
can only respond now....

What's missing from your MSI enabling code is the PVM mask/unmask 
required on the Quark X1000 bridge - for *all* downstream devices using MSI.

I realise it's not an upstreaming friendly piece of code - however - 
without the PVM mask operation all MSIs on Quark should be considered 
unreliable.

Maybe you guys have submitted patches to the PCI layer on this already ? 
If so feel free to ignore.

If not then please re-evaluate all MSI enabling code.

 From the original

http://downloadmirror.intel.com/23171/eng/Board_Support_Package_Sources_for_Intel_Quark_v1.0.0.7z

+#if defined(CONFIG_INTEL_QUARK_X1000_SOC)
+	#define mask_pvm(x) qrk_pci_pvm_mask(x)
+	#define unmask_pvm(x) qrk_pci_pvm_unmask(x)
+#else
+	#define mask_pvm(x)
+	#define unmask_pvm(x)
+#endif
+
  static irqreturn_t stmmac_interrupt(int irq, void *dev_id)
  {
  	struct net_device *dev = (struct net_device *)dev_id;
@@ -1601,10 +1686,12 @@ static irqreturn_t stmmac_interrupt(int irq, 
void *dev_id)
  		return IRQ_NONE;
  	}

+	mask_pvm(priv->pdev);
+
  	/* To handle GMAC own interrupts */
  	if (priv->plat->has_gmac) {
-		int status = priv->hw->mac->host_irq_status((void __iomem *)
-							    dev->base_addr);
+		int status = priv->hw->mac->host_irq_status(priv);
+
  		if (unlikely(status)) {
  			if (status & core_mmc_tx_irq)
  				priv->xstats.mmc_tx_irq_n++;
@@ -1634,6 +1721,8 @@ static irqreturn_t stmmac_interrupt(int irq, void 
*dev_id)
  	/* To handle DMA interrupts */
  	stmmac_dma_interrupt(priv);

+	unmask_pvm(priv->pdev);
+
  	return IRQ_HANDLED;
  }