PCI: Get rid of dev->has_secondary_link flag
In some systems, the Device/Port Type in the PCI Express Capabilities
register incorrectly identifies upstream ports as downstream ports.
d0751b98dfa3 ("PCI: Add dev->has_secondary_link to track downstream PCIe
links") addressed this by adding pci_dev.has_secondary_link, which is set
for downstream ports. But this is confusing because pci_pcie_type()
sometimes gives the wrong answer, and it's not obvious that we should use
pci_dev.has_secondary_link instead.
Reduce the confusion by correcting the type of the port itself so that
pci_pcie_type() returns the actual type regardless of what the Device/Port
Type register claims it is. Update the users to call pci_pcie_type() and
pcie_downstream_port() accordingly, and remove pci_dev.has_secondary_link
completely.
Link: https://lore.kernel.org/linux-pci/20190703133953.GK128603@google.com/
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20190822085553.62697-2-mika.westerberg@linux.intel.com
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 29ed5ec..97e7f6e 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3576,7 +3576,7 @@ int pci_enable_atomic_ops_to_root(struct pci_dev *dev, u32 cap_mask)
}
/* Ensure upstream ports don't block AtomicOps on egress */
- if (!bridge->has_secondary_link) {
+ if (pci_pcie_type(bridge) == PCI_EXP_TYPE_UPSTREAM) {
pcie_capability_read_dword(bridge, PCI_EXP_DEVCTL2,
&ctl2);
if (ctl2 & PCI_EXP_DEVCTL2_ATOMIC_EGRESS_BLOCK)
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index e44af7f..dcda968 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -913,10 +913,10 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
/*
* We allocate pcie_link_state for the component on the upstream
- * end of a Link, so there's nothing to do unless this device has a
- * Link on its secondary side.
+ * end of a Link, so there's nothing to do unless this device is
+ * downstream port.
*/
- if (!pdev->has_secondary_link)
+ if (!pcie_downstream_port(pdev))
return;
/* VIA has a strange chipset, root port is under a bridge */
@@ -1070,7 +1070,7 @@ static int __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem)
if (!pci_is_pcie(pdev))
return 0;
- if (pdev->has_secondary_link)
+ if (pcie_downstream_port(pdev))
parent = pdev;
if (!parent || !parent->link_state)
return -EINVAL;
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 773197a..b0e6048 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -166,7 +166,7 @@ static pci_ers_result_t reset_link(struct pci_dev *dev, u32 service)
driver = pcie_port_find_service(dev, service);
if (driver && driver->reset_link) {
status = driver->reset_link(dev);
- } else if (dev->has_secondary_link) {
+ } else if (pcie_downstream_port(dev)) {
status = default_reset_link(dev);
} else {
pci_printk(KERN_DEBUG, dev, "no link-reset support at upstream device %s\n",
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index cdf34a3c..3bfa57d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1431,26 +1431,38 @@ void set_pcie_port_type(struct pci_dev *pdev)
pci_read_config_word(pdev, pos + PCI_EXP_DEVCAP, ®16);
pdev->pcie_mpss = reg16 & PCI_EXP_DEVCAP_PAYLOAD;
+ parent = pci_upstream_bridge(pdev);
+ if (!parent)
+ return;
+
/*
- * A Root Port or a PCI-to-PCIe bridge is always the upstream end
- * of a Link. No PCIe component has two Links. Two Links are
- * connected by a Switch that has a Port on each Link and internal
- * logic to connect the two Ports.
+ * Some systems do not identify their upstream/downstream ports
+ * correctly so detect impossible configurations here and correct
+ * the port type accordingly.
*/
type = pci_pcie_type(pdev);
- if (type == PCI_EXP_TYPE_ROOT_PORT ||
- type == PCI_EXP_TYPE_PCIE_BRIDGE)
- pdev->has_secondary_link = 1;
- else if (type == PCI_EXP_TYPE_UPSTREAM ||
- type == PCI_EXP_TYPE_DOWNSTREAM) {
- parent = pci_upstream_bridge(pdev);
-
+ if (type == PCI_EXP_TYPE_DOWNSTREAM) {
/*
- * Usually there's an upstream device (Root Port or Switch
- * Downstream Port), but we can't assume one exists.
+ * If pdev claims to be downstream port but the parent
+ * device is also downstream port assume pdev is actually
+ * upstream port.
*/
- if (parent && !parent->has_secondary_link)
- pdev->has_secondary_link = 1;
+ if (pcie_downstream_port(parent)) {
+ pci_info(pdev, "claims to be downstream port but is acting as upstream port, correcting type\n");
+ pdev->pcie_flags_reg &= ~PCI_EXP_FLAGS_TYPE;
+ pdev->pcie_flags_reg |= PCI_EXP_TYPE_UPSTREAM;
+ }
+ } else if (type == PCI_EXP_TYPE_UPSTREAM) {
+ /*
+ * If pdev claims to be upstream port but the parent
+ * device is also upstream port assume pdev is actually
+ * downstream port.
+ */
+ if (pci_pcie_type(parent) == PCI_EXP_TYPE_UPSTREAM) {
+ pci_info(pdev, "claims to be upstream port but is acting as downstream port, correcting type\n");
+ pdev->pcie_flags_reg &= ~PCI_EXP_FLAGS_TYPE;
+ pdev->pcie_flags_reg |= PCI_EXP_TYPE_DOWNSTREAM;
+ }
}
}
@@ -2488,12 +2500,8 @@ static int only_one_child(struct pci_bus *bus)
* A PCIe Downstream Port normally leads to a Link with only Device
* 0 on it (PCIe spec r3.1, sec 7.3.1). As an optimization, scan
* only for Device 0 in that situation.
- *
- * Checking has_secondary_link is a hack to identify Downstream
- * Ports because sometimes Switches are configured such that the
- * PCIe Port Type labels are backwards.
*/
- if (bridge && pci_is_pcie(bridge) && bridge->has_secondary_link)
+ if (bridge && pci_is_pcie(bridge) && pcie_downstream_port(bridge))
return 1;
return 0;
diff --git a/drivers/pci/vc.c b/drivers/pci/vc.c
index 5acd9c0..9ae9fb9 100644
--- a/drivers/pci/vc.c
+++ b/drivers/pci/vc.c
@@ -13,6 +13,8 @@
#include <linux/pci_regs.h>
#include <linux/types.h>
+#include "pci.h"
+
/**
* pci_vc_save_restore_dwords - Save or restore a series of dwords
* @dev: device
@@ -105,7 +107,7 @@ static void pci_vc_enable(struct pci_dev *dev, int pos, int res)
struct pci_dev *link = NULL;
/* Enable VCs from the downstream device */
- if (!dev->has_secondary_link)
+ if (!pci_is_pcie(dev) || !pcie_downstream_port(dev))
return;
ctrl_pos = pos + PCI_VC_RES_CTRL + (res * PCI_CAP_VC_PER_VC_SIZEOF);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 9e700d9..0153ede 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -418,7 +418,6 @@ struct pci_dev {
unsigned int broken_intx_masking:1; /* INTx masking can't be used */
unsigned int io_window_1k:1; /* Intel bridge 1K I/O windows */
unsigned int irq_managed:1;
- unsigned int has_secondary_link:1;
unsigned int non_compliant_bars:1; /* Broken BARs; ignore them */
unsigned int is_probed:1; /* Device probing in progress */
unsigned int link_active_reporting:1;/* Device capable of reporting link active */
