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PCI: Add generic pcie_wait_for_link() interface

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Clients such as hotplug and Downstream Port Containment (DPC) both need to
wait until a link becomes active or inactive.

Add a generic pcie_wait_link_active() interface and use it instead of
duplicating the code.

Signed-off-by: Oza Pawandeep <poza@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
This commit is contained in:
Oza Pawandeep 2018-05-17 16:44:11 -05:00 committed by Bjorn Helgaas
parent 2af8641b2a
commit 9f5a70f18c
4 changed files with 34 additions and 28 deletions
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20
drivers/pci/hotplug/pciehp_hpc.c
View file

@ -231,25 +231,11 @@ bool pciehp_check_link_active(struct controller *ctrl)
return ret;
}
static void __pcie_wait_link_active(struct controller *ctrl, bool active)
{
int timeout = 1000;
if (pciehp_check_link_active(ctrl) == active)
return;
while (timeout > 0) {
msleep(10);
timeout -= 10;
if (pciehp_check_link_active(ctrl) == active)
return;
}
ctrl_dbg(ctrl, "Data Link Layer Link Active not %s in 1000 msec\n",
active ? "set" : "cleared");
}
static void pcie_wait_link_active(struct controller *ctrl)
{
__pcie_wait_link_active(ctrl, true);
struct pci_dev *pdev = ctrl_dev(ctrl);
pcie_wait_for_link(pdev, true);
}
static bool pci_bus_check_dev(struct pci_bus *bus, int devfn)

29
drivers/pci/pci.c
View file

@ -4138,6 +4138,35 @@ static int pci_pm_reset(struct pci_dev *dev, int probe)
return pci_dev_wait(dev, "PM D3->D0", PCIE_RESET_READY_POLL_MS);
}
/**
* pcie_wait_for_link - Wait until link is active or inactive
* @pdev: Bridge device
* @active: waiting for active or inactive?
*
* Use this to wait till link becomes active or inactive.
*/
bool pcie_wait_for_link(struct pci_dev *pdev, bool active)
{
int timeout = 1000;
bool ret;
u16 lnk_status;
for (;;) {
pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
if (ret == active)
return true;
if (timeout <= 0)
break;
msleep(10);
timeout -= 10;
}
pci_info(pdev, "Data Link Layer Link Active not %s in 1000 msec\n",
active ? "set" : "cleared");
return false;
}
void pci_reset_secondary_bus(struct pci_dev *dev)
{

1
drivers/pci/pci.h
View file

@ -353,6 +353,7 @@ static inline resource_size_t pci_resource_alignment(struct pci_dev *dev,
void pci_enable_acs(struct pci_dev *dev);
bool pcie_wait_for_link(struct pci_dev *pdev, bool active);
#ifdef CONFIG_PCIEASPM
void pcie_aspm_init_link_state(struct pci_dev *pdev);
void pcie_aspm_exit_link_state(struct pci_dev *pdev);

12
drivers/pci/pcie/dpc.c
View file

@ -68,19 +68,9 @@ static int dpc_wait_rp_inactive(struct dpc_dev *dpc)
static void dpc_wait_link_inactive(struct dpc_dev *dpc)
{
unsigned long timeout = jiffies + HZ;
struct pci_dev *pdev = dpc->dev->port;
struct device *dev = &dpc->dev->device;
u16 lnk_status;
pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
while (lnk_status & PCI_EXP_LNKSTA_DLLLA &&
!time_after(jiffies, timeout)) {
msleep(10);
pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
}
if (lnk_status & PCI_EXP_LNKSTA_DLLLA)
dev_warn(dev, "Link state not disabled for DPC event\n");
pcie_wait_for_link(pdev, false);
}
static void dpc_work(struct work_struct *work)