On 2014/10/23 13:18, Bjorn Helgaas wrote:

On Wed, Oct 15, 2014 at 11:06:53AM +0800, Yijing Wang wrote:

quoted

Save msi chip in pci_sys_data instead of assign
msi chip to every pci bus in .add_bus().

Signed-off-by: Yijing Wang <redacted>
---
 drivers/pci/host/pci-tegra.c |   13 +++----------
 1 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index 3d43874..5af0525 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c

@@ -694,15 +694,6 @@ static int tegra_pcie_map_irq(const struct pci_dev *pdev, u8 slot, u8 pin)
 	return irq;
 }
 
-static void tegra_pcie_add_bus(struct pci_bus *bus)
-{
-	if (IS_ENABLED(CONFIG_PCI_MSI)) {
-		struct tegra_pcie *pcie = sys_to_pcie(bus->sysdata);
-
-		bus->msi = &pcie->msi.chip;
-	}
-}
-
 static struct pci_bus *tegra_pcie_scan_bus(int nr, struct pci_sys_data *sys)
 {
 	struct tegra_pcie *pcie = sys_to_pcie(sys);

@@ -1881,11 +1872,13 @@ static int tegra_pcie_enable(struct tegra_pcie *pcie)
 
 	memset(&hw, 0, sizeof(hw));
 
+#ifdef CONFIG_PCI_MSI
+	hw.msi_chip = &pcie->msi.chip;
+#endif

Why did you use "#ifdef CONFIG_PCI_MSI" instead of the
"IS_ENABLED(CONFIG_PCI_MSI)" used previously?

Just personal habit. :)

It's true that CONFIG_PCI_MSI will never be a tristate symbol, so we don't
really *need* the extra smarts of IS_ENABLED(), but I'm fairly sympathetic
to James' argument [1] that we should just use IS_ENABLED() all the time
because it's simpler overall.

If you want to change the #ifdef to IS_ENABLED(), that should be a separate
patch from your msi_chip change, and we can debate the merits of that by
itself.

[1] http://lkml.iu.edu//hypermail/linux/kernel/1204.3/00081.html

Hi Bjorn, thanks for your guidance. I will use IS_ENABLED() instead of #ifdef for simplification
in a separate patch.

quoted

 	hw.nr_controllers = 1;
 	hw.private_data = (void **)&pcie;
 	hw.setup = tegra_pcie_setup;
 	hw.map_irq = tegra_pcie_map_irq;
-	hw.add_bus = tegra_pcie_add_bus;
 	hw.scan = tegra_pcie_scan_bus;
 	hw.ops = &tegra_pcie_ops;
 
-- 
1.7.1

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.

-- 
Thanks!
Yijing