[PATCH v8 43/46] pci-bridge/cxl_upstream: Add a CXL switch upstream port

[Jonathan Cameron via <qemu-devel@nongnu.org>]

An initial simple upstream port emulation to allow the creation
of CXL switches. The Device ID has been allocated for this use.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 hw/pci-bridge/cxl_upstream.c | 205 +++++++++++++++++++++++++++++++++++
 hw/pci-bridge/meson.build    |   2 +-
 include/hw/cxl/cxl.h         |   4 +
 3 files changed, 210 insertions(+), 1 deletion(-)

diff --git a/hw/pci-bridge/cxl_upstream.c b/hw/pci-bridge/cxl_upstream.c
new file mode 100644
index 0000000000..f95e01b373
--- /dev/null
+++ b/hw/pci-bridge/cxl_upstream.c
@@ -0,0 +1,205 @@
+/*
+ * Emulated CXL Switch Upstream Port
+ *
+ * Copyright (c) 2022 Huawei Technologies.
+ *
+ * Based on xio31130_upstream.c
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "hw/pci/msi.h"
+#include "hw/pci/pcie.h"
+#include "hw/pci/pcie_port.h"
+
+#define CXL_UPSTREAM_PORT_MSI_NR_VECTOR 1
+
+#define CXL_UPSTREAM_PORT_MSI_OFFSET 0x70
+#define CXL_UPSTREAM_PORT_PCIE_CAP_OFFSET 0x90
+#define CXL_UPSTREAM_PORT_AER_OFFSET 0x100
+#define CXL_UPSTREAM_PORT_DVSEC_OFFSET \
+    (CXL_UPSTREAM_PORT_AER_OFFSET + PCI_ERR_SIZEOF)
+
+typedef struct CXLUpstreamPort {
+    /*< private >*/
+    PCIEPort parent_obj;
+
+    /*< public >*/
+    CXLComponentState cxl_cstate;
+} CXLUpstreamPort;
+
+CXLComponentState *cxl_usp_to_cstate(CXLUpstreamPort *usp)
+{
+    return &usp->cxl_cstate;
+}
+
+static void cxl_usp_dvsec_write_config(PCIDevice *dev, uint32_t addr,
+                                       uint32_t val, int len)
+{
+    CXLUpstreamPort *usp = CXL_USP(dev);
+
+    if (range_contains(&usp->cxl_cstate.dvsecs[EXTENSIONS_PORT_DVSEC], addr)) {
+        uint8_t *reg = &dev->config[addr];
+        addr -= usp->cxl_cstate.dvsecs[EXTENSIONS_PORT_DVSEC].lob;
+        if (addr == PORT_CONTROL_OFFSET) {
+            if (pci_get_word(reg) & PORT_CONTROL_UNMASK_SBR) {
+                /* unmask SBR */
+            }
+            if (pci_get_word(reg) & PORT_CONTROL_ALT_MEMID_EN) {
+                /* Alt Memory & ID Space Enable */
+            }
+        }
+    }
+}
+
+static void cxl_usp_write_config(PCIDevice *d, uint32_t address,
+                                 uint32_t val, int len)
+{
+    pci_bridge_write_config(d, address, val, len);
+    pcie_cap_flr_write_config(d, address, val, len);
+    pcie_aer_write_config(d, address, val, len);
+
+    cxl_usp_dvsec_write_config(d, address, val, len);
+}
+
+static void latch_registers(CXLUpstreamPort *usp)
+{
+    uint32_t *reg_state = usp->cxl_cstate.crb.cache_mem_registers;
+
+    cxl_component_register_init_common(reg_state, CXL2_UPSTREAM_PORT);
+    ARRAY_FIELD_DP32(reg_state, CXL_HDM_DECODER_CAPABILITY, TARGET_COUNT, 8);
+}
+
+static void cxl_usp_reset(DeviceState *qdev)
+{
+    PCIDevice *d = PCI_DEVICE(qdev);
+    CXLUpstreamPort *usp = CXL_USP(qdev);
+
+    pci_bridge_reset(qdev);
+    pcie_cap_deverr_reset(d);
+    latch_registers(usp);
+}
+
+static void build_dvsecs(CXLComponentState *cxl)
+{
+    uint8_t *dvsec;
+
+    dvsec = (uint8_t *)&(struct cxl_dvsec_port_extensions){ 0 };
+    cxl_component_create_dvsec(cxl, EXTENSIONS_PORT_DVSEC_LENGTH,
+                               EXTENSIONS_PORT_DVSEC,
+                               EXTENSIONS_PORT_DVSEC_REVID, dvsec);
+    dvsec = (uint8_t *)&(struct cxl_dvsec_port_flexbus){
+        .cap                     = 0x26, /* IO, Mem, non-MLD */
+        .ctrl                    = 0,
+        .status                  = 0x26, /* same */
+        .rcvd_mod_ts_data_phase1 = 0xef, /* WTF? */
+    };
+    cxl_component_create_dvsec(cxl, PCIE_FLEXBUS_PORT_DVSEC_LENGTH_2_0,
+                               PCIE_FLEXBUS_PORT_DVSEC,
+                               PCIE_FLEXBUS_PORT_DVSEC_REVID_2_0, dvsec);
+
+    dvsec = (uint8_t *)&(struct cxl_dvsec_register_locator){
+        .rsvd         = 0,
+        .reg0_base_lo = RBI_COMPONENT_REG | CXL_COMPONENT_REG_BAR_IDX,
+        .reg0_base_hi = 0,
+    };
+    cxl_component_create_dvsec(cxl, REG_LOC_DVSEC_LENGTH, REG_LOC_DVSEC,
+                               REG_LOC_DVSEC_REVID, dvsec);
+}
+
+static void cxl_usp_realize(PCIDevice *d, Error **errp)
+{
+    PCIEPort *p = PCIE_PORT(d);
+    CXLUpstreamPort *usp = CXL_USP(d);
+    CXLComponentState *cxl_cstate = &usp->cxl_cstate;
+    ComponentRegisters *cregs = &cxl_cstate->crb;
+    MemoryRegion *component_bar = &cregs->component_registers;
+    int rc;
+
+    pci_bridge_initfn(d, TYPE_PCIE_BUS);
+    pcie_port_init_reg(d);
+
+    rc = msi_init(d, CXL_UPSTREAM_PORT_MSI_OFFSET,
+                  CXL_UPSTREAM_PORT_MSI_NR_VECTOR, true, true, errp);
+    if (rc) {
+        assert(rc == -ENOTSUP);
+        goto err_bridge;
+    }
+
+    rc = pcie_cap_init(d, CXL_UPSTREAM_PORT_PCIE_CAP_OFFSET,
+                       PCI_EXP_TYPE_UPSTREAM, p->port, errp);
+    if (rc < 0) {
+        goto err_msi;
+    }
+
+    pcie_cap_flr_init(d);
+    pcie_cap_deverr_init(d);
+    rc = pcie_aer_init(d, PCI_ERR_VER, CXL_UPSTREAM_PORT_AER_OFFSET,
+                       PCI_ERR_SIZEOF, errp);
+    if (rc) {
+        goto err_cap;
+    }
+
+    cxl_cstate->dvsec_offset = CXL_UPSTREAM_PORT_DVSEC_OFFSET;
+    cxl_cstate->pdev = d;
+    build_dvsecs(cxl_cstate);
+    cxl_component_register_block_init(OBJECT(d), cxl_cstate, TYPE_CXL_USP);
+    pci_register_bar(d, CXL_COMPONENT_REG_BAR_IDX,
+                     PCI_BASE_ADDRESS_SPACE_MEMORY |
+                     PCI_BASE_ADDRESS_MEM_TYPE_64,
+                     component_bar);
+
+    return;
+
+err_cap:
+    pcie_cap_exit(d);
+err_msi:
+    msi_uninit(d);
+err_bridge:
+    pci_bridge_exitfn(d);
+}
+
+static void cxl_usp_exitfn(PCIDevice *d)
+{
+    pcie_aer_exit(d);
+    pcie_cap_exit(d);
+    msi_uninit(d);
+    pci_bridge_exitfn(d);
+}
+
+static void cxl_upstream_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+    PCIDeviceClass *k = PCI_DEVICE_CLASS(oc);
+
+    k->is_bridge = true;
+    k->config_write = cxl_usp_write_config;
+    k->realize = cxl_usp_realize;
+    k->exit = cxl_usp_exitfn;
+    k->vendor_id = 0x19e5; /* Huawei */
+    k->device_id = 0xa128; /* Emulated CXL Switch Upstream Port */
+    k->revision = 0;
+    set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
+    dc->desc = "CXL Switch Upstream Port";
+    dc->reset = cxl_usp_reset;
+}
+
+static const TypeInfo cxl_usp_info = {
+    .name = TYPE_CXL_USP,
+    .parent = TYPE_PCIE_PORT,
+    .instance_size = sizeof(CXLUpstreamPort),
+    .class_init = cxl_upstream_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        { INTERFACE_PCIE_DEVICE },
+        { INTERFACE_CXL_DEVICE },
+        { }
+    },
+};
+
+static void cxl_usp_register_type(void)
+{
+    type_register_static(&cxl_usp_info);
+}
+
+type_init(cxl_usp_register_type);
diff --git a/hw/pci-bridge/meson.build b/hw/pci-bridge/meson.build
index b6d26a03d5..4a8c26b5a1 100644
--- a/hw/pci-bridge/meson.build
+++ b/hw/pci-bridge/meson.build
@@ -5,7 +5,7 @@ pci_ss.add(when: 'CONFIG_IOH3420', if_true: files('ioh3420.c'))
 pci_ss.add(when: 'CONFIG_PCIE_PORT', if_true: files('pcie_root_port.c', 'gen_pcie_root_port.c', 'pcie_pci_bridge.c'))
 pci_ss.add(when: 'CONFIG_PXB', if_true: files('pci_expander_bridge.c'))
 pci_ss.add(when: 'CONFIG_XIO3130', if_true: files('xio3130_upstream.c', 'xio3130_downstream.c'))
-pci_ss.add(when: 'CONFIG_CXL', if_true: files('cxl_root_port.c'))
+pci_ss.add(when: 'CONFIG_CXL', if_true: files('cxl_root_port.c', 'cxl_upstream.c'))
 
 # NewWorld PowerMac
 pci_ss.add(when: 'CONFIG_DEC_PCI', if_true: files('dec.c'))
diff --git a/include/hw/cxl/cxl.h b/include/hw/cxl/cxl.h
index 14194acead..a9a2e6c405 100644
--- a/include/hw/cxl/cxl.h
+++ b/include/hw/cxl/cxl.h
@@ -46,5 +46,9 @@ void cxl_fixed_memory_window_options_set(MachineState *ms,
 void cxl_fixed_memory_window_link_targets(Error **errp);
 
 extern const MemoryRegionOps cfmws_ops;
+#define TYPE_CXL_USP "cxl-upstream"
 
+typedef struct CXLUpstreamPort CXLUpstreamPort;
+DECLARE_INSTANCE_CHECKER(CXLUpstreamPort, CXL_USP, TYPE_CXL_USP)
+CXLComponentState *cxl_usp_to_cstate(CXLUpstreamPort *usp);
 #endif
-- 
2.32.0