[PATCH v1 5/5] pci: keystone: add pcie driver based on designware core driver

On Thu, May 15, 2014 at 08:20:13PM +0200, Arnd Bergmann wrote:

On Thursday 15 May 2014 13:45:08 Murali Karicheri wrote:

quoted

quoted

quoted

+#ifdef CONFIG_PCI_KEYSTONE
+/*
+ * The KeyStone PCIe controller has maximum read request size of 256 bytes.
+ */
+static void quirk_limit_readrequest(struct pci_dev *dev)
+{
+    int readrq = pcie_get_readrq(dev);
+
+    if (readrq > 256)
+            pcie_set_readrq(dev, 256);
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, quirk_limit_readrequest);
+#endif /* CONFIG_PCI_KEYSTONE */

This doesn't work: you can't just limit do this for all devices just based
on PCI_KEYSTONE being enabled, you have to check if you are actually using
this controller.

      Arnd

  I assume, I need to check if PCI controller's vendor ID/ device ID 
match with the keystone
  PCI controller's ID and call pcie_set_readrq() for all of the slave 
PCI devices and do this fixup.
Is this correct understanding?  If you can point me to an example code 
for this that will be
really helpful so that I can avoid re-inventing the wheel.

I think it would be best to move the quirk into the keystone pci driver
and compare compare the dev->driver pointer of the PCI controller device.

The PCI core handles setting the maximum read request size already,
can you figure out why the core code isn't doing what you need and
correct the root problem?

I'm guessing the values in the root port bridge config space are not
correct or something like that??

Jason