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    SubjectRe: [RFC PATCH] PCIe: Add PCIe runtime D3cold support
    On 04/13/2012 02:06 PM, Alex He wrote:
    > 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.
    >
    I can't make PME interrupt work in mint spring platform. Our internal RTD3 document say:
    "A device in RTD3 is prohibited from generating any activity other than wake event, through the WAKE# pin"

    >>
    >> 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.

    To set a device to D3cold. We first set device to D3hot through PMCSR register,
    then cut the power supply through ACPI.

    Regards
    Yan, Zheng

    >
    >>
    >> 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 */
    >>
    >> --
    >> To unsubscribe from this list: send the line "unsubscribe linux-pm" in
    >> the body of a message to majordomo@vger.kernel.org
    >> More majordomo info at http://vger.kernel.org/majordomo-info.html
    >>
    >



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