* Stephen Warren wrote:

On 06/11/2012 09:05 AM, Thierry Reding wrote:

quoted

This commit adds support for message signaled interrupts to the Tegra
PCIe controller. Based on code by Krishna Kishore [off-list ref].

quoted

diff --git a/arch/arm/mach-tegra/pcie.c b/arch/arm/mach-tegra/pcie.c

quoted

+static irqreturn_t tegra_pcie_msi_irq(int irq, void *data)

...

quoted

+			irq = irq_find_mapping(pcie->msi->domain, index);
+			if (irq) {
+				if (test_bit(index, pcie->msi->used))
+					generic_handle_irq(irq);

This invokes the handler first ...

...

quoted

+			/* clear the interrupt */
+			afi_writel(pcie, 1 << offset, AFI_MSI_VEC0 + i * 4);
+			/* see if there's any more pending in this vector */
+			reg = afi_readl(pcie, AFI_MSI_VEC0 + i * 4);

... then clears the interrupt status in the PCIe controller. Won't that
lose interrupts if one is raised between when the handler clears the
root-cause, and when this code clears the received interrupt status?

It certainly doesn't follow the conventional way of clearing the interrupt
first. I carried this from the original MSI patch, but I'll move the
interrupt clearing up and retest.

quoted

+static int tegra_pcie_disable_msi(struct platform_device *pdev)

Should this free pcie->msi->pages?

Yes it should. I actually mention making that change in the changelog but
in fact didn't.

Why allocate pcie->msi separately; why not include the fields directly
into struct tegra_pcie_info *pcie?

For one I find this easier to read. If this wasn't a separate structure, each
of the individual fields would get an msi_ prefix anyway so there isn't much
to be gained from keeping them directly in tegra_pcie_info.

Second, and more importantly, this will keep the size of struct
tegra_pcie_info smaller if PCI_MSI is not selected because there is just one
unused pointer instead of five unused fields.

Thierry
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