[PATCH -v4 1/2] PCIe: Add runtime PM support to PCIe port

Huang Ying
2012-05-18T01:49:03Z

From: "Yan, Zheng" <zheng.z.yan@intel.com>

This patch adds runtime PM support to PCIe port. This is needed by
PCIe D3cold support, where PCIe device without ACPI node may be
powered on/off by PCIe port.

Because runtime suspend is broken for some chipsets, a black list is
used to disable runtime PM support for these chipsets.

Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
---
drivers/pci/pci.c | 10 ++++++++++
drivers/pci/pcie/portdrv_pci.c | 24 ++++++++++++++++++++++++
2 files changed, 34 insertions(+)

--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1517,6 +1517,16 @@ static void pci_pme_list_scan(struct wor
if (!list_empty(&pci_pme_list)) {
list_for_each_entry_safe(pme_dev, n, &pci_pme_list, list) {
if (pme_dev->dev->pme_poll) {
+ struct pci_dev *bridge;
+
+ bridge = pme_dev->dev->bus->self;
+ /*
+ * If bridge is in low power state, the
+ * configuration space of subordinate devices
+ * may be not accessible
+ */
+ if (bridge && bridge->current_state != PCI_D0)
+ continue;
pci_pme_wakeup(pme_dev->dev, NULL);
} else {
list_del(&pme_dev->list);
--- a/drivers/pci/pcie/portdrv_pci.c
+++ b/drivers/pci/pcie/portdrv_pci.c
@@ -11,6 +11,7 @@
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/pm.h>
+#include <linux/pm_runtime.h>
#include <linux/init.h>
#include <linux/pcieport_if.h>
#include <linux/aer.h>
@@ -99,6 +100,15 @@ static int pcie_port_resume_noirq(struct
return 0;
}

+#ifdef CONFIG_PM_RUNTIME
+static int pcie_port_runtime_pm(struct device *dev)
+{
+ return 0;
+}
+#else
+#define pcie_port_runtime_pm NULL
+#endif
+
static const struct dev_pm_ops pcie_portdrv_pm_ops = {
.suspend = pcie_port_device_suspend,
.resume = pcie_port_device_resume,
@@ -107,6 +117,8 @@ static const struct dev_pm_ops pcie_port
.poweroff = pcie_port_device_suspend,
.restore = pcie_port_device_resume,
.resume_noirq = pcie_port_resume_noirq,
+ .runtime_suspend = pcie_port_runtime_pm,
+ .runtime_resume = pcie_port_runtime_pm,
};

#define PCIE_PORTDRV_PM_OPS (&pcie_portdrv_pm_ops)
@@ -117,6 +129,14 @@ static const struct dev_pm_ops pcie_port
#endif /* !PM */

/*
+ * PCIe port runtime suspend is broken for some chipsets, so use a
+ * black list to disable runtime PM for these chipsets.
+ */
+static const struct pci_device_id port_runtime_pm_black_list[] = {
+ { /* end: all zeroes */ }
+};
+
+/*
* pcie_portdrv_probe - Probe PCI-Express port devices
* @dev: PCI-Express port device being probed
*
@@ -144,12 +164,16 @@ static int __devinit pcie_portdrv_probe(
return status;

pci_save_state(dev);
+ if (!pci_match_id(port_runtime_pm_black_list, dev))
+ pm_runtime_put_noidle(&dev->dev);

return 0;
}

static void pcie_portdrv_remove(struct pci_dev *dev)
{
+ if (!pci_match_id(port_runtime_pm_black_list, dev))
+ pm_runtime_get_noresume(&dev->dev);
pcie_port_device_remove(dev);
pci_disable_device(dev);
}