From 454593e54cac126a0f49d4b65f90a5e518c51404 Mon Sep 17 00:00:00 2001 From: Gavin Shan Date: Wed, 11 Jan 2017 11:50:08 +1100 Subject: [PATCH] drivers/pci/hotplug: Mask PDC interrupt if required We're supporting surprise hotplug on PCI slots behind root port or PCIe switch downstream ports, which don't claim the capability in hardware register (offset: PCIe cap + PCI_EXP_SLTCAP). PEX8718 is one of the examples. For those PCI slots, the PDC (Presence Detection Change) event isn't reliable and the underly (skiboot) firmware has best judgement. This masks the PDC event when skiboot requests by "ibm,slot-broken-pdc" property in PCI slot's device-tree node. Reported-by: Hank Chang Signed-off-by: Gavin Shan Tested-by: Willie Liauw Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/pnv-pci.h | 2 ++ drivers/pci/hotplug/pnv_php.c | 27 ++++++++++++++++++++++----- 2 files changed, 24 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/pnv-pci.h b/arch/powerpc/include/asm/pnv-pci.h index 696438f09aea..de9681034353 100644 --- a/arch/powerpc/include/asm/pnv-pci.h +++ b/arch/powerpc/include/asm/pnv-pci.h @@ -57,6 +57,8 @@ struct pnv_php_slot { uint64_t id; char *name; int slot_no; + unsigned int flags; +#define PNV_PHP_FLAG_BROKEN_PDC 0x1 struct kref kref; #define PNV_PHP_STATE_INITIALIZED 0 #define PNV_PHP_STATE_REGISTERED 1 diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c index 41304b313512..63cd9f354b79 100644 --- a/drivers/pci/hotplug/pnv_php.c +++ b/drivers/pci/hotplug/pnv_php.c @@ -717,7 +717,8 @@ static irqreturn_t pnv_php_interrupt(int irq, void *data) if (sts & PCI_EXP_SLTSTA_DLLSC) { pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lsts); added = !!(lsts & PCI_EXP_LNKSTA_DLLLA); - } else if (sts & PCI_EXP_SLTSTA_PDC) { + } else if (!(php_slot->flags & PNV_PHP_FLAG_BROKEN_PDC) && + (sts & PCI_EXP_SLTSTA_PDC)) { ret = pnv_pci_get_presence_state(php_slot->id, &presence); if (ret) { dev_warn(&pdev->dev, "PCI slot [%s] error %d getting presence (0x%04x), to retry the operation.\n", @@ -768,6 +769,7 @@ static irqreturn_t pnv_php_interrupt(int irq, void *data) static void pnv_php_init_irq(struct pnv_php_slot *php_slot, int irq) { struct pci_dev *pdev = php_slot->pdev; + u32 broken_pdc = 0; u16 sts, ctrl; int ret; @@ -779,9 +781,18 @@ static void pnv_php_init_irq(struct pnv_php_slot *php_slot, int irq) return; } + /* Check PDC (Presence Detection Change) is broken or not */ + ret = of_property_read_u32(php_slot->dn, "ibm,slot-broken-pdc", + &broken_pdc); + if (!ret && broken_pdc) + php_slot->flags |= PNV_PHP_FLAG_BROKEN_PDC; + /* Clear pending interrupts */ pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &sts); - sts |= (PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC); + if (php_slot->flags & PNV_PHP_FLAG_BROKEN_PDC) + sts |= PCI_EXP_SLTSTA_DLLSC; + else + sts |= (PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC); pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, sts); /* Request the interrupt */ @@ -795,9 +806,15 @@ static void pnv_php_init_irq(struct pnv_php_slot *php_slot, int irq) /* Enable the interrupts */ pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &ctrl); - ctrl |= (PCI_EXP_SLTCTL_HPIE | - PCI_EXP_SLTCTL_PDCE | - PCI_EXP_SLTCTL_DLLSCE); + if (php_slot->flags & PNV_PHP_FLAG_BROKEN_PDC) { + ctrl &= ~PCI_EXP_SLTCTL_PDCE; + ctrl |= (PCI_EXP_SLTCTL_HPIE | + PCI_EXP_SLTCTL_DLLSCE); + } else { + ctrl |= (PCI_EXP_SLTCTL_HPIE | + PCI_EXP_SLTCTL_PDCE | + PCI_EXP_SLTCTL_DLLSCE); + } pcie_capability_write_word(pdev, PCI_EXP_SLTCTL, ctrl); /* The interrupt is initialized successfully when @irq is valid */