PCI: don't enable ASPM on devices with mixed PCIe/PCI functions

The Slot 03:00.* of JMicron controller has two functions, but one is
PCIE endpoint the other isn't PCIE device, very strange. PCIE spec
defines all functions should have the same config for ASPM, so disable
ASPM for the whole slot in this case.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 61fedb24..f824955 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -506,6 +506,23 @@ static void free_link_state(struct pci_dev *pdev)
 	pdev->link_state = NULL;
 }
 
+static int pcie_aspm_sanity_check(struct pci_dev *pdev)
+{
+	struct pci_dev *child_dev;
+	int child_pos;
+
+	/*
+	 * Some functions in a slot might not all be PCIE functions, very
+	 * strange. Disable ASPM for the whole slot
+	 */
+	list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
+		child_pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
+		if (!child_pos)
+			return -EINVAL;
+	}
+	return 0;
+}
+
 /*
  * pcie_aspm_init_link_state: Initiate PCI express link state.
  * It is called after the pcie and its children devices are scaned.
@@ -526,6 +543,9 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
 	if (list_empty(&pdev->subordinate->devices))
 		goto out;
 
+	if (pcie_aspm_sanity_check(pdev))
+		goto out;
+
 	mutex_lock(&aspm_lock);
 
 	link_state = kzalloc(sizeof(*link_state), GFP_KERNEL);