[PATCH v3 04/10] PCI/RCEC: Add pcie_walk_rcec() to walk associated RCiEPs

Sean V Kelley
2020-08-12T16:48:04Z

From: Qiuxu Zhuo <qiuxu.zhuo@intel.com>

When an RCEC device signals error(s) to a CPU core, the CPU core
needs to walk all the RCiEPs associated with that RCEC to check
errors. So add the function pcie_walk_rcec() to walk all RCiEPs
associated with the RCEC device.

Co-developed-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
drivers/pci/pci.h | 4 +++
drivers/pci/pcie/rcec.c | 76 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 80 insertions(+)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index bd25e6047b54..8bd7528d6977 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -473,9 +473,13 @@ static inline void pci_dpc_init(struct pci_dev *pdev) {}
#ifdef CONFIG_PCIEPORTBUS
void pci_rcec_init(struct pci_dev *dev);
void pci_rcec_exit(struct pci_dev *dev);
+void pcie_walk_rcec(struct pci_dev *rcec, int (*cb)(struct pci_dev *, void *),
+ void *userdata);
#else
static inline void pci_rcec_init(struct pci_dev *dev) {}
static inline void pci_rcec_exit(struct pci_dev *dev) {}
+static inline void pcie_walk_rcec(struct pci_dev *rcec, int (*cb)(struct pci_dev *, void *),
+ void *userdata) {}
#endif

#ifdef CONFIG_PCI_ATS
diff --git a/drivers/pci/pcie/rcec.c b/drivers/pci/pcie/rcec.c
index 519ae086ff41..405f92fcdf7f 100644
--- a/drivers/pci/pcie/rcec.c
+++ b/drivers/pci/pcie/rcec.c
@@ -17,6 +17,82 @@

#include "../pci.h"

+static int pcie_walk_rciep_devfn(struct pci_bus *bus, int (*cb)(struct pci_dev *, void *),
+ void *userdata, const unsigned long bitmap)
+{
+ unsigned int devn, fn;
+ struct pci_dev *dev;
+ int retval;
+
+ for_each_set_bit(devn, &bitmap, 32) {
+ for (fn = 0; fn < 8; fn++) {
+ dev = pci_get_slot(bus, PCI_DEVFN(devn, fn));
+
+ if (!dev)
+ continue;
+
+ if (pci_pcie_type(dev) != PCI_EXP_TYPE_RC_END) {
+ pci_dev_put(dev);
+ continue;
+ }
+
+ retval = cb(dev, userdata);
+ pci_dev_put(dev);
+ if (retval)
+ return retval;
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * pcie_walk_rcec - Walk RCiEP devices associating with RCEC and call callback.
+ * @rcec RCEC whose RCiEP devices should be walked.
+ * @cb Callback to be called for each RCiEP device found.
+ * @userdata Arbitrary pointer to be passed to callback.
+ *
+ * Walk the given RCEC. Call the provided callback on each RCiEP device found.
+ *
+ * We check the return of @cb each time. If it returns anything
+ * other than 0, we break out.
+ */
+void pcie_walk_rcec(struct pci_dev *rcec, int (*cb)(struct pci_dev *, void *),
+ void *userdata)
+{
+ u8 nextbusn, lastbusn;
+ struct pci_bus *bus;
+ unsigned int bnr;
+
+ if (!rcec->rcec_cap)
+ return;
+
+ /* Find RCiEP devices on the same bus as the RCEC */
+ if (pcie_walk_rciep_devfn(rcec->bus, cb, userdata, rcec->rcec_ext->bitmap))
+ return;
+
+ /* Check whether RCEC BUSN register is present */
+ if (rcec->rcec_ext->ver < PCI_RCEC_BUSN_REG_VER)
+ return;
+
+ nextbusn = rcec->rcec_ext->nextbusn;
+ lastbusn = rcec->rcec_ext->lastbusn;
+
+ /* All RCiEP devices are on the same bus as the RCEC */
+ if (nextbusn == 0xff && lastbusn == 0x00)
+ return;
+
+ for (bnr = nextbusn; bnr <= lastbusn; bnr++) {
+ bus = pci_find_bus(pci_domain_nr(rcec->bus), bnr);
+ if (!bus)
+ continue;
+
+ /* Find RCiEP devices on the given bus */
+ if (pcie_walk_rciep_devfn(bus, cb, userdata, 0xffffffff))
+ return;
+ }
+}
+
void pci_rcec_init(struct pci_dev *dev)
{
u32 rcec, hdr, busn;
--
2.28.0