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Commit d92a208d authored by Gavin Shan's avatar Gavin Shan Committed by Benjamin Herrenschmidt
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powerpc/pci: Mask linkDown on resetting PCI bus 



The problem was initially reported by Wendy who tried pass through
IPR adapter, which was connected to PHB root port directly, to KVM
based guest. When doing that, pci_reset_bridge_secondary_bus() was
called by VFIO driver and linkDown was detected by the root port.
That caused all PEs to be frozen.

The patch fixes the issue by routing the reset for the secondary bus
of root port to underly firmware. For that, one more weak function
pci_reset_secondary_bus() is introduced so that the individual platforms
can override that and do specific reset for bridge's secondary bus.

Reported-by: default avatarWendy Xiong <wenxiong@linux.vnet.ibm.com>
Signed-off-by: default avatarGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 26833a50

arch/powerpc/include/asm/machdep.h

+3 −0
Original line number Diff line number Diff line
@@ -241,6 +241,9 @@ struct machdep_calls { 
	/* Called during PCI resource reassignment */

	resource_size_t (*pcibios_window_alignment)(struct pci_bus *, unsigned long type);



	/* Reset the secondary bus of bridge */

	void  (*pcibios_reset_secondary_bus)(struct pci_dev *dev);



	/* Called to shutdown machine specific hardware not already controlled

	 * by other drivers.

	 */

arch/powerpc/kernel/pci-common.c

+20 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/string.h>

#include <linux/init.h>

#include <linux/bootmem.h>

#include <linux/delay.h>

#include <linux/export.h>

#include <linux/of_address.h>

#include <linux/of_pci.h>
@@ -120,6 +121,25 @@ resource_size_t pcibios_window_alignment(struct pci_bus *bus, 
	return 1;

}



void pcibios_reset_secondary_bus(struct pci_dev *dev)

{

	u16 ctrl;



	if (ppc_md.pcibios_reset_secondary_bus) {

		ppc_md.pcibios_reset_secondary_bus(dev);

		return;

	}



	pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &ctrl);

	ctrl |= PCI_BRIDGE_CTL_BUS_RESET;

	pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);

	msleep(2);



	ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;

	pci_write_config_word(dev, PCI_BRIDGE_CONTROL, ctrl);

	ssleep(1);

}



static resource_size_t pcibios_io_size(const struct pci_controller *hose)

{

#ifdef CONFIG_PPC64

arch/powerpc/platforms/powernv/eeh-ioda.c

+36 −2
Original line number Diff line number Diff line
@@ -474,6 +474,8 @@ static int ioda_eeh_bridge_reset(struct pci_dev *dev, int option) 


{

	struct device_node *dn = pci_device_to_OF_node(dev);

	struct eeh_dev *edev = of_node_to_eeh_dev(dn);

	int aer = edev ? edev->aer_cap : 0;

	u32 ctrl;



	pr_debug("%s: Reset PCI bus %04x:%02x with option %d\n",
@@ -483,24 +485,56 @@ static int ioda_eeh_bridge_reset(struct pci_dev *dev, int option) 
	switch (option) {

	case EEH_RESET_FUNDAMENTAL:

	case EEH_RESET_HOT:

		/* Don't report linkDown event */

		if (aer) {

			eeh_ops->read_config(dn, aer + PCI_ERR_UNCOR_MASK,

					     4, &ctrl);

			ctrl |= PCI_ERR_UNC_SURPDN;

                        eeh_ops->write_config(dn, aer + PCI_ERR_UNCOR_MASK,

					      4, ctrl);

                }



		eeh_ops->read_config(dn, PCI_BRIDGE_CONTROL, 2, &ctrl);

		ctrl |= PCI_BRIDGE_CTL_BUS_RESET;

		eeh_ops->write_config(dn, PCI_BRIDGE_CONTROL, 2, ctrl);



		msleep(EEH_PE_RST_HOLD_TIME);



		break;

	case EEH_RESET_DEACTIVATE:

		eeh_ops->read_config(dn, PCI_BRIDGE_CONTROL, 2, &ctrl);

		ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;

		eeh_ops->write_config(dn, PCI_BRIDGE_CONTROL, 2, ctrl);



		msleep(EEH_PE_RST_SETTLE_TIME);



		/* Continue reporting linkDown event */

		if (aer) {

			eeh_ops->read_config(dn, aer + PCI_ERR_UNCOR_MASK,

					     4, &ctrl);

			ctrl &= ~PCI_ERR_UNC_SURPDN;

			eeh_ops->write_config(dn, aer + PCI_ERR_UNCOR_MASK,

					      4, ctrl);

		}



		break;

	}



	return 0;

}



void pnv_pci_reset_secondary_bus(struct pci_dev *dev)

{

	struct pci_controller *hose;



	if (pci_is_root_bus(dev->bus)) {

		hose = pci_bus_to_host(dev->bus);

		ioda_eeh_root_reset(hose, EEH_RESET_HOT);

		ioda_eeh_root_reset(hose, EEH_RESET_DEACTIVATE);

	} else {

		ioda_eeh_bridge_reset(dev, EEH_RESET_HOT);

		ioda_eeh_bridge_reset(dev, EEH_RESET_DEACTIVATE);

	}

}



/**

 * ioda_eeh_reset - Reset the indicated PE

 * @pe: EEH PE

arch/powerpc/platforms/powernv/pci-ioda.c

+1 −0
Original line number Diff line number Diff line
@@ -1386,6 +1386,7 @@ void __init pnv_pci_init_ioda_phb(struct device_node *np, 
	ppc_md.pcibios_fixup = pnv_pci_ioda_fixup;

	ppc_md.pcibios_enable_device_hook = pnv_pci_enable_device_hook;

	ppc_md.pcibios_window_alignment = pnv_pci_window_alignment;

	ppc_md.pcibios_reset_secondary_bus = pnv_pci_reset_secondary_bus;

	pci_add_flags(PCI_REASSIGN_ALL_RSRC);



	/* Reset IODA tables to a clean state */

arch/powerpc/platforms/powernv/pci.h

+1 −0
Original line number Diff line number Diff line
@@ -204,5 +204,6 @@ extern void pnv_pci_init_ioda_hub(struct device_node *np); 
extern void pnv_pci_init_ioda2_phb(struct device_node *np);

extern void pnv_pci_ioda_tce_invalidate(struct iommu_table *tbl,

					__be64 *startp, __be64 *endp, bool rm);

extern void pnv_pci_reset_secondary_bus(struct pci_dev *dev);



#endif /* __POWERNV_PCI_H */