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    SubjectRe: [RFC PATCH] PCIe: Add PCIe runtime D3cold support
    On Fri, Apr 13, 2012 at 10:35:34AM +0800, Yan, Zheng wrote:
    > Hi all,
    >
    > This patch adds PCIe runtime D3cold support, namely cut power supply for functions
    > beneath a PCIe port when they all have entered D3. A device in D3cold can only
    > generate wake event through the WAKE# pin. Because we can not access to a device's
    > configure space while it's in D3cold, pme_poll is disabled for devices in D3cold.
    >
    > Any comment will be appreciated.
    >
    > Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
    > ---
    > diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
    > index 0f150f2..e210e8cb 100644
    > --- a/drivers/pci/pci-acpi.c
    > +++ b/drivers/pci/pci-acpi.c
    > @@ -224,7 +224,7 @@ static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
    > [PCI_D1] = ACPI_STATE_D1,
    > [PCI_D2] = ACPI_STATE_D2,
    > [PCI_D3hot] = ACPI_STATE_D3,
    > - [PCI_D3cold] = ACPI_STATE_D3
    > + [PCI_D3cold] = ACPI_STATE_D3_COLD
    > };
    > int error = -EINVAL;
    >
    > @@ -296,7 +296,8 @@ static void acpi_pci_propagate_run_wake(struct pci_bus *bus, bool enable)
    >
    > static int acpi_pci_run_wake(struct pci_dev *dev, bool enable)
    > {
    > - if (dev->pme_interrupt)
    > + /* PME interrupt isn't available in the D3cold case */
    > + if (dev->pme_interrupt && !dev->runtime_d3cold)
    > return 0;
    PCI BUS PM Interface spec says that PMEs can be support for D3COLD.
    Please check section 3.2.4 , 5.4.2 and 5.4.3.


    >
    > if (!acpi_pm_device_run_wake(&dev->dev, enable))
    > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
    > index 8156744..bc16869 100644
    > --- a/drivers/pci/pci.c
    > +++ b/drivers/pci/pci.c
    > @@ -731,8 +731,8 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
    > int error;
    >
    > /* bound the state we're entering */
    > - if (state > PCI_D3hot)
    > - state = PCI_D3hot;
    > + if (state > PCI_D3cold)
    > + state = PCI_D3cold;
    > else if (state < PCI_D0)
    > state = PCI_D0;
    > else if ((state == PCI_D1 || state == PCI_D2) && pci_no_d1d2(dev))
    > @@ -750,7 +750,8 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
    > if (state == PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3))
    > return 0;
    >
    > - error = pci_raw_set_power_state(dev, state);
    > + error = pci_raw_set_power_state(dev, state > PCI_D3hot ?
    > + PCI_D3hot : state);
    Do you want to set the pci device to D3hot if the state = D3Code through
    PMCSR register? I am agree if you realy want that but what is the meaninig
    to distingulish D3cold with D3hot in this patch. We can't put the PCI device
    through PMCSR register.

    >
    > if (!__pci_complete_power_transition(dev, state))
    > error = 0;
    > @@ -1482,6 +1483,17 @@ bool pci_pme_capable(struct pci_dev *dev, pci_power_t state)
    > return !!(dev->pme_support & (1 << state));
    > }
    >
    > +static void pci_pme_poll_wakeup(struct pci_dev *dev)
    > +{
    > + struct pci_dev *bridge = dev->bus->self;
    > +
    > + /* don't poll the pme bit if parent is in low power state */
    > + if (bridge && bridge->current_state != PCI_D0)
    > + return;
    > +
    > + pci_pme_wakeup(dev, NULL);
    > +}
    > +
    > static void pci_pme_list_scan(struct work_struct *work)
    > {
    > struct pci_pme_device *pme_dev, *n;
    > @@ -1490,7 +1502,7 @@ static void pci_pme_list_scan(struct work_struct *work)
    > if (!list_empty(&pci_pme_list)) {
    > list_for_each_entry_safe(pme_dev, n, &pci_pme_list, list) {
    > if (pme_dev->dev->pme_poll) {
    > - pci_pme_wakeup(pme_dev->dev, NULL);
    > + pci_pme_poll_wakeup(pme_dev->dev);
    > } else {
    > list_del(&pme_dev->list);
    > kfree(pme_dev);
    > @@ -1608,6 +1620,10 @@ int __pci_enable_wake(struct pci_dev *dev, pci_power_t state,
    > if (enable) {
    > int error;
    >
    > + if (runtime && state >= PCI_D3cold)
    > + dev->runtime_d3cold = true;
    > + else
    > + dev->runtime_d3cold = false;
    > if (pci_pme_capable(dev, state))
    > pci_pme_active(dev, true);
    > else
    > diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
    > index e0610bd..d66b7e9 100644
    > --- a/drivers/pci/pcie/portdrv_pci.c
    > +++ b/drivers/pci/pcie/portdrv_pci.c
    > @@ -11,11 +11,13 @@
    > #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>
    > #include <linux/dmi.h>
    > #include <linux/pci-aspm.h>
    > +#include <linux/delay.h>
    >
    > #include "portdrv.h"
    > #include "aer/aerdrv.h"
    > @@ -99,6 +101,25 @@ static int pcie_port_resume_noirq(struct device *dev)
    > return 0;
    > }
    >
    > +static int pcie_port_runtime_suspend(struct device *dev)
    > +{
    > + struct pci_dev *pdev = to_pci_dev(dev);
    > +
    > + pci_save_state(pdev);
    > + return 0;
    > +}
    > +
    > +static int pcie_port_runtime_resume(struct device *dev)
    > +{
    > + struct pci_dev *pdev = to_pci_dev(dev);
    > +
    > + pci_restore_state(pdev);
    > + if (pdev->runtime_d3cold)
    > + msleep(100);
    > +
    > + return 0;
    > +}
    > +
    > static const struct dev_pm_ops pcie_portdrv_pm_ops = {
    > .suspend = pcie_port_device_suspend,
    > .resume = pcie_port_device_resume,
    > @@ -107,6 +128,8 @@ static const struct dev_pm_ops pcie_portdrv_pm_ops = {
    > .poweroff = pcie_port_device_suspend,
    > .restore = pcie_port_device_resume,
    > .resume_noirq = pcie_port_resume_noirq,
    > + .runtime_suspend = pcie_port_runtime_suspend,
    > + .runtime_resume = pcie_port_runtime_resume,
    > };
    >
    > #define PCIE_PORTDRV_PM_OPS (&pcie_portdrv_pm_ops)
    > @@ -144,12 +167,14 @@ static int __devinit pcie_portdrv_probe(struct pci_dev *dev,
    > return status;
    >
    > pci_save_state(dev);
    > + pm_runtime_put_noidle(&dev->dev);
    >
    > return 0;
    > }
    >
    > static void pcie_portdrv_remove(struct pci_dev *dev)
    > {
    > + pm_runtime_get_noresume(&dev->dev);
    > pcie_port_device_remove(dev);
    > pci_disable_device(dev);
    > }
    > diff --git a/include/linux/pci.h b/include/linux/pci.h
    > index e444f5b..b41d9a1 100644
    > --- a/include/linux/pci.h
    > +++ b/include/linux/pci.h
    > @@ -281,6 +281,7 @@ struct pci_dev {
    > unsigned int no_d1d2:1; /* Only allow D0 and D3 */
    > unsigned int mmio_always_on:1; /* disallow turning off io/mem
    > decoding during bar sizing */
    > + unsigned int runtime_d3cold:1;
    > unsigned int wakeup_prepared:1;
    > unsigned int d3_delay; /* D3->D0 transition time in ms */
    >
    > --
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    > More majordomo info at http://vger.kernel.org/majordomo-info.html
    >



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