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Commit 62ce94a7 authored by Sinan Kaya's avatar Sinan Kaya Committed by Bjorn Helgaas
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PCI: Mark Broadcom HT2100 Root Port Extended Tags as broken 

Per PCIe r3.1, sec 2.2.6.2 and 7.8.4, a Requester may not use 8-bit Tags
unless its Extended Tag Field Enable is set, but all Receivers/Completers
must handle 8-bit Tags correctly regardless of their Extended Tag Field
Enable.

Some devices do not handle 8-bit Tags as Completers, so add a quirk for
them.  If we find such a device, we disable Extended Tags for the entire
hierarchy to make peer-to-peer DMA possible.

The Broadcom HT2100 seems to have issues with handling 8-bit tags.  Mark it
as broken.

The pci_walk_bus() in the quirk handles devices we've enumerated in the
past, and pci_configure_device() handles devices we enumerate in the
future.

Fixes: 60db3a4d ("PCI: Enable PCIe Extended Tags if supported")
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1467674


Reported-and-tested-by: default avatarWim ten Have <wim.ten.have@oracle.com>
Signed-off-by: default avatarSinan Kaya <okaya@codeaurora.org>
[bhelgaas: changelog, tweak messages, rename bit and quirk]
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 16f73eb0

drivers/pci/pci.h

+1 −0
Original line number Diff line number Diff line
@@ -235,6 +235,7 @@ enum pci_bar_type { 
	pci_bar_mem64,		/* A 64-bit memory BAR */

};



int pci_configure_extended_tags(struct pci_dev *dev, void *ign);

bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *pl,

				int crs_timeout);

int pci_setup_device(struct pci_dev *dev);

drivers/pci/probe.c

+36 −7
Original line number Diff line number Diff line
@@ -1745,22 +1745,51 @@ static void program_hpp_type2(struct pci_dev *dev, struct hpp_type2 *hpp) 
	 */

}



static void pci_configure_extended_tags(struct pci_dev *dev)

int pci_configure_extended_tags(struct pci_dev *dev, void *ign)

{

	u32 dev_cap;

	struct pci_host_bridge *host;

	u32 cap;

	u16 ctl;

	int ret;



	if (!pci_is_pcie(dev))

		return;

		return 0;



	ret = pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &dev_cap);

	ret = pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);

	if (ret)

		return;

		return 0;



	if (!(cap & PCI_EXP_DEVCAP_EXT_TAG))

		return 0;



	ret = pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &ctl);

	if (ret)

		return 0;



	host = pci_find_host_bridge(dev->bus);

	if (!host)

		return 0;



	/*

	 * If some device in the hierarchy doesn't handle Extended Tags

	 * correctly, make sure they're disabled.

	 */

	if (host->no_ext_tags) {

		if (ctl & PCI_EXP_DEVCTL_EXT_TAG) {

			dev_info(&dev->dev, "disabling Extended Tags\n");

			pcie_capability_clear_word(dev, PCI_EXP_DEVCTL,

						   PCI_EXP_DEVCTL_EXT_TAG);

		}

		return 0;

	}



	if (dev_cap & PCI_EXP_DEVCAP_EXT_TAG)

	if (!(ctl & PCI_EXP_DEVCTL_EXT_TAG)) {

		dev_info(&dev->dev, "enabling Extended Tags\n");

		pcie_capability_set_word(dev, PCI_EXP_DEVCTL,

					 PCI_EXP_DEVCTL_EXT_TAG);

	}

	return 0;

}



static void pci_configure_device(struct pci_dev *dev)

{
@@ -1768,7 +1797,7 @@ static void pci_configure_device(struct pci_dev *dev) 
	int ret;



	pci_configure_mps(dev);

	pci_configure_extended_tags(dev);

	pci_configure_extended_tags(dev, NULL);



	memset(&hpp, 0, sizeof(hpp));

	ret = pci_get_hp_params(dev, &hpp);

drivers/pci/quirks.c

+16 −0
Original line number Diff line number Diff line
@@ -4681,3 +4681,19 @@ static void quirk_intel_no_flr(struct pci_dev *dev) 
}

DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1502, quirk_intel_no_flr);

DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1503, quirk_intel_no_flr);



static void quirk_no_ext_tags(struct pci_dev *pdev)

{

	struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->bus);



	if (!bridge)

		return;



	bridge->no_ext_tags = 1;

	dev_info(&pdev->dev, "disabling Extended Tags (this device can't handle them)\n");



	pci_walk_bus(bridge->bus, pci_configure_extended_tags, NULL);

}

DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SERVERWORKS, 0x0140, quirk_no_ext_tags);

DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SERVERWORKS, 0x0142, quirk_no_ext_tags);

DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SERVERWORKS, 0x0144, quirk_no_ext_tags);

include/linux/pci.h

+1 −0
Original line number Diff line number Diff line
@@ -451,6 +451,7 @@ struct pci_host_bridge { 
	void *release_data;

	struct msi_controller *msi;

	unsigned int ignore_reset_delay:1;	/* for entire hierarchy */

	unsigned int no_ext_tags:1;		/* no Extended Tags */

	/* Resource alignment requirements */

	resource_size_t (*align_resource)(struct pci_dev *dev,

			const struct resource *res,