From: Dongjoo Seo <[email protected]>

Implement the Streamlined Virtual Channel (SVC) extended capability
for PCIe ports (Root, Upstream, and Downstream). This capability is
mandatory for enabling Unordered IO (UIO) traffic as per PCIe 6.4
specification [1].

UIO functionality depends on two key prerequisites:
  1. SVC support (SVC3 mandatory, SVC4 optional)
  2. 256-byte Flit mode support

This patch adds the following experimental properties to PCIe ports:
  - x-uio-svc: Enable UIO traffic via SVC3 (mandatory path)
  - x-uio-svc-opt: Enable UIO traffic via SVC4 (optional path)
  - x-256b-flit: Enable 256B flit mode required for UIO

Helper functions are included to manage UIO traffic gating and SVC
configuration. This change lays the groundwork for UIO emulation in
QEMU.

[1]: PCIe 6.4 Specification, Table 2-46 (Streamlined Virtual Channel)

Signed-off-by: Dongjoo Seo <[email protected]>
Signed-off-by: Shrihari E S <[email protected]>
---
 hw/pci-bridge/pcie_root_port.c     |  2 ++
 hw/pci-bridge/xio3130_downstream.c |  3 +++
 hw/pci-bridge/xio3130_upstream.c   |  8 ++++++++
 include/hw/pci/pcie_port.h         | 21 +++++++++++++++++++++
 4 files changed, 34 insertions(+)

diff --git a/hw/pci-bridge/pcie_root_port.c b/hw/pci-bridge/pcie_root_port.c
index eeee24e042..20554bd854 100644
--- a/hw/pci-bridge/pcie_root_port.c
+++ b/hw/pci-bridge/pcie_root_port.c
@@ -153,6 +153,8 @@ static const Property rp_props[] = {
                     QEMU_PCIE_SLTCAP_PCP_BITNR, true),
     DEFINE_PROP_BOOL("disable-acs", PCIESlot, disable_acs, false),
     DEFINE_PROP_BOOL("x-256b-flit", PCIEPort, flitmode, true),
+    DEFINE_PROP_BIT("x-uio-svc", PCIEPort, svc, UIO_MANDATORY_SVC, false),
+    DEFINE_PROP_BIT("x-uio-svc-opt", PCIEPort, svc, UIO_OPTIONAL_SVC, false),
 };
 
 static void rp_instance_post_init(Object *obj)
diff --git a/hw/pci-bridge/xio3130_downstream.c 
b/hw/pci-bridge/xio3130_downstream.c
index 0c3fed3053..b0b297bb53 100644
--- a/hw/pci-bridge/xio3130_downstream.c
+++ b/hw/pci-bridge/xio3130_downstream.c
@@ -137,6 +137,9 @@ static void xio3130_downstream_exitfn(PCIDevice *d)
 static const Property xio3130_downstream_props[] = {
     DEFINE_PROP_BIT(COMPAT_PROP_PCP, PCIDevice, cap_present,
                     QEMU_PCIE_SLTCAP_PCP_BITNR, true),
+    DEFINE_PROP_BIT("x-uio-svc", PCIEPort, svc, UIO_MANDATORY_SVC, false),
+    DEFINE_PROP_BIT("x-uio-svc-opt", PCIEPort, svc, UIO_OPTIONAL_SVC, false),
+    DEFINE_PROP_BOOL("x-256b-flit", PCIEPort, flitmode, false),
 };
 
 static const VMStateDescription vmstate_xio3130_downstream = {
diff --git a/hw/pci-bridge/xio3130_upstream.c b/hw/pci-bridge/xio3130_upstream.c
index 40057b749b..925df5add3 100644
--- a/hw/pci-bridge/xio3130_upstream.c
+++ b/hw/pci-bridge/xio3130_upstream.c
@@ -24,6 +24,7 @@
 #include "hw/pci/msi.h"
 #include "hw/pci/pcie.h"
 #include "hw/pci/pcie_port.h"
+#include "hw/core/qdev-properties.h"
 #include "migration/vmstate.h"
 #include "qemu/module.h"
 
@@ -123,6 +124,12 @@ static const VMStateDescription vmstate_xio3130_upstream = 
{
     }
 };
 
+static const Property xio3130_upstream_props[] = {
+    DEFINE_PROP_BIT("x-uio-svc", PCIEPort, svc, UIO_MANDATORY_SVC, false),
+    DEFINE_PROP_BIT("x-uio-svc-opt", PCIEPort, svc, UIO_OPTIONAL_SVC, false),
+    DEFINE_PROP_BOOL("x-256b-flit", PCIEPort, flitmode, false),
+};
+
 static void xio3130_upstream_class_init(ObjectClass *klass, const void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
@@ -138,6 +145,7 @@ static void xio3130_upstream_class_init(ObjectClass *klass, 
const void *data)
     dc->desc = "TI X3130 Upstream Port of PCI Express Switch";
     device_class_set_legacy_reset(dc, xio3130_upstream_reset);
     dc->vmsd = &vmstate_xio3130_upstream;
+    device_class_set_props(dc, xio3130_upstream_props);
 }
 
 static const TypeInfo xio3130_upstream_info = {
diff --git a/include/hw/pci/pcie_port.h b/include/hw/pci/pcie_port.h
index 1bcc734649..a6b1b8a6cf 100644
--- a/include/hw/pci/pcie_port.h
+++ b/include/hw/pci/pcie_port.h
@@ -37,8 +37,29 @@ struct PCIEPort {
 
     /* pci express switch port */
     uint8_t     port;
+
+    /*
+     * This field declares Streamlined Virtual Channel (SVC) capability.
+     * Per PCIe 6.4 specification section 7.9.29, a pcie port supports
+     * upto 8 SVCs, in that SVC0 is a default one, SVC3 is for UIO traffic
+     * and SVC 4 is shared by both UIO and non-UIO traffic.
+     */
+    uint32_t    svc;
 };
 
+#define UIO_MANDATORY_SVC 3
+#define UIO_OPTIONAL_SVC 4
+
+static inline bool get_uio_mandatory_svc(PCIEPort *port)
+{
+    return (port->svc >> UIO_MANDATORY_SVC) & 1;
+}
+
+static inline bool get_uio_optional_svc(PCIEPort *port)
+{
+    return (port->svc >> UIO_OPTIONAL_SVC) & 1;
+}
+
 void pcie_port_init_reg(PCIDevice *d);
 
 PCIDevice *pcie_find_port_by_pn(PCIBus *bus, uint8_t pn);
-- 
2.34.1


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