hw: xilinx-pcie: Add support for Xilinx AXI PCIe Controller

Add support for emulating the Xilinx AXI Root Port Bridge for PCI
Express as described by Xilinx' PG055 document. This is a PCIe
controller that can be used with certain series of Xilinx FPGAs, and is
used on the MIPS Boston board which will make use of this code.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
[yongbok.kim@imgtec.com:
  removed returning on !level,
  updated IRQ connection with GPIO logic,
  moved xilinx_pcie_init() to boston.c
  replaced stw_le_p() with pci_set_word()
  and other cosmetic changes]
Signed-off-by: Yongbok Kim <yongbok.kim@imgtec.com>

3 files changed, 397 insertions, 0 deletions

diff --git a/hw/pci-host/Makefile.objs b/hw/pci-host/Makefile.objs
index 45f1f0e..9c7909c 100644
--- a/hw/pci-host/Makefile.objs
+++ b/hw/pci-host/Makefile.objs
@@ -16,3 +16,4 @@ common-obj-$(CONFIG_FULONG) += bonito.o
 common-obj-$(CONFIG_PCI_PIIX) += piix.o
 common-obj-$(CONFIG_PCI_Q35) += q35.o
 common-obj-$(CONFIG_PCI_GENERIC) += gpex.o
+common-obj-$(CONFIG_PCI_XILINX) += xilinx-pcie.o
diff --git a/hw/pci-host/xilinx-pcie.c b/hw/pci-host/xilinx-pcie.c
new file mode 100644
index 0000000..8b71e2d
--- /dev/null
+++ b/hw/pci-host/xilinx-pcie.c
@@ -0,0 +1,328 @@
+/*
+ * Xilinx PCIe host controller emulation.
+ *
+ * Copyright (c) 2016 Imagination Technologies
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/pci/pci_bridge.h"
+#include "hw/pci-host/xilinx-pcie.h"
+
+enum root_cfg_reg {
+    /* Interrupt Decode Register */
+    ROOTCFG_INTDEC              = 0x138,
+
+    /* Interrupt Mask Register */
+    ROOTCFG_INTMASK             = 0x13c,
+    /* INTx Interrupt Received */
+#define ROOTCFG_INTMASK_INTX    (1 << 16)
+    /* MSI Interrupt Received */
+#define ROOTCFG_INTMASK_MSI     (1 << 17)
+
+    /* PHY Status/Control Register */
+    ROOTCFG_PSCR                = 0x144,
+    /* Link Up */
+#define ROOTCFG_PSCR_LINK_UP    (1 << 11)
+
+    /* Root Port Status/Control Register */
+    ROOTCFG_RPSCR               = 0x148,
+    /* Bridge Enable */
+#define ROOTCFG_RPSCR_BRIDGEEN  (1 << 0)
+    /* Interrupt FIFO Not Empty */
+#define ROOTCFG_RPSCR_INTNEMPTY (1 << 18)
+    /* Interrupt FIFO Overflow */
+#define ROOTCFG_RPSCR_INTOVF    (1 << 19)
+
+    /* Root Port Interrupt FIFO Read Register 1 */
+    ROOTCFG_RPIFR1              = 0x158,
+#define ROOTCFG_RPIFR1_INT_LANE_SHIFT   27
+#define ROOTCFG_RPIFR1_INT_ASSERT_SHIFT 29
+#define ROOTCFG_RPIFR1_INT_VALID_SHIFT  31
+    /* Root Port Interrupt FIFO Read Register 2 */
+    ROOTCFG_RPIFR2              = 0x15c,
+};
+
+static void xilinx_pcie_update_intr(XilinxPCIEHost *s,
+                                    uint32_t set, uint32_t clear)
+{
+    int level;
+
+    s->intr |= set;
+    s->intr &= ~clear;
+
+    if (s->intr_fifo_r != s->intr_fifo_w) {
+        s->intr |= ROOTCFG_INTMASK_INTX;
+    }
+
+    level = !!(s->intr & s->intr_mask);
+    qemu_set_irq(s->irq, level);
+}
+
+static void xilinx_pcie_queue_intr(XilinxPCIEHost *s,
+                                   uint32_t fifo_reg1, uint32_t fifo_reg2)
+{
+    XilinxPCIEInt *intr;
+    unsigned int new_w;
+
+    new_w = (s->intr_fifo_w + 1) % ARRAY_SIZE(s->intr_fifo);
+    if (new_w == s->intr_fifo_r) {
+        s->rpscr |= ROOTCFG_RPSCR_INTOVF;
+        return;
+    }
+
+    intr = &s->intr_fifo[s->intr_fifo_w];
+    s->intr_fifo_w = new_w;
+
+    intr->fifo_reg1 = fifo_reg1;
+    intr->fifo_reg2 = fifo_reg2;
+
+    xilinx_pcie_update_intr(s, ROOTCFG_INTMASK_INTX, 0);
+}
+
+static void xilinx_pcie_set_irq(void *opaque, int irq_num, int level)
+{
+    XilinxPCIEHost *s = XILINX_PCIE_HOST(opaque);
+
+    xilinx_pcie_queue_intr(s,
+       (irq_num << ROOTCFG_RPIFR1_INT_LANE_SHIFT) |
+           (level << ROOTCFG_RPIFR1_INT_ASSERT_SHIFT) |
+           (1 << ROOTCFG_RPIFR1_INT_VALID_SHIFT),
+       0);
+}
+
+static void xilinx_pcie_host_realize(DeviceState *dev, Error **errp)
+{
+    PCIHostState *pci = PCI_HOST_BRIDGE(dev);
+    XilinxPCIEHost *s = XILINX_PCIE_HOST(dev);
+    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+    PCIExpressHost *pex = PCIE_HOST_BRIDGE(dev);
+
+    snprintf(s->name, sizeof(s->name), "pcie%u", s->bus_nr);
+
+    /* PCI configuration space */
+    pcie_host_mmcfg_init(pex, s->cfg_size);
+
+    /* MMIO region */
+    memory_region_init(&s->mmio, OBJECT(s), "mmio", UINT64_MAX);
+    memory_region_set_enabled(&s->mmio, false);
+
+    /* dummy I/O region */
+    memory_region_init_ram(&s->io, OBJECT(s), "io", 16, NULL);
+    memory_region_set_enabled(&s->io, false);
+
+    /* interrupt out */
+    qdev_init_gpio_out_named(dev, &s->irq, "interrupt_out", 1);
+
+    sysbus_init_mmio(sbd, &pex->mmio);
+    sysbus_init_mmio(sbd, &s->mmio);
+
+    pci->bus = pci_register_bus(dev, s->name, xilinx_pcie_set_irq,
+                                pci_swizzle_map_irq_fn, s, &s->mmio,
+                                &s->io, 0, 4, TYPE_PCIE_BUS);
+
+    qdev_set_parent_bus(DEVICE(&s->root), BUS(pci->bus));
+    qdev_init_nofail(DEVICE(&s->root));
+}
+
+static const char *xilinx_pcie_host_root_bus_path(PCIHostState *host_bridge,
+                                                  PCIBus *rootbus)
+{
+    return "0000:00";
+}
+
+static void xilinx_pcie_host_init(Object *obj)
+{
+    XilinxPCIEHost *s = XILINX_PCIE_HOST(obj);
+    XilinxPCIERoot *root = &s->root;
+
+    object_initialize(root, sizeof(*root), TYPE_XILINX_PCIE_ROOT);
+    object_property_add_child(obj, "root", OBJECT(root), NULL);
+    qdev_prop_set_uint32(DEVICE(root), "addr", PCI_DEVFN(0, 0));
+    qdev_prop_set_bit(DEVICE(root), "multifunction", false);
+}
+
+static Property xilinx_pcie_host_props[] = {
+    DEFINE_PROP_UINT32("bus_nr", XilinxPCIEHost, bus_nr, 0),
+    DEFINE_PROP_SIZE("cfg_base", XilinxPCIEHost, cfg_base, 0),
+    DEFINE_PROP_SIZE("cfg_size", XilinxPCIEHost, cfg_size, 32 << 20),
+    DEFINE_PROP_SIZE("mmio_base", XilinxPCIEHost, mmio_base, 0),
+    DEFINE_PROP_SIZE("mmio_size", XilinxPCIEHost, mmio_size, 1 << 20),
+    DEFINE_PROP_BOOL("link_up", XilinxPCIEHost, link_up, true),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void xilinx_pcie_host_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    PCIHostBridgeClass *hc = PCI_HOST_BRIDGE_CLASS(klass);
+
+    hc->root_bus_path = xilinx_pcie_host_root_bus_path;
+    dc->realize = xilinx_pcie_host_realize;
+    set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
+    dc->fw_name = "pci";
+    dc->props = xilinx_pcie_host_props;
+}
+
+static const TypeInfo xilinx_pcie_host_info = {
+    .name       = TYPE_XILINX_PCIE_HOST,
+    .parent     = TYPE_PCIE_HOST_BRIDGE,
+    .instance_size = sizeof(XilinxPCIEHost),
+    .instance_init = xilinx_pcie_host_init,
+    .class_init = xilinx_pcie_host_class_init,
+};
+
+static uint32_t xilinx_pcie_root_config_read(PCIDevice *d,
+                                             uint32_t address, int len)
+{
+    XilinxPCIEHost *s = XILINX_PCIE_HOST(OBJECT(d)->parent);
+    uint32_t val;
+
+    switch (address) {
+    case ROOTCFG_INTDEC:
+        val = s->intr;
+        break;
+    case ROOTCFG_INTMASK:
+        val = s->intr_mask;
+        break;
+    case ROOTCFG_PSCR:
+        val = s->link_up ? ROOTCFG_PSCR_LINK_UP : 0;
+        break;
+    case ROOTCFG_RPSCR:
+        if (s->intr_fifo_r != s->intr_fifo_w) {
+            s->rpscr &= ~ROOTCFG_RPSCR_INTNEMPTY;
+        } else {
+            s->rpscr |= ROOTCFG_RPSCR_INTNEMPTY;
+        }
+        val = s->rpscr;
+        break;
+    case ROOTCFG_RPIFR1:
+        if (s->intr_fifo_w == s->intr_fifo_r) {
+            /* FIFO empty */
+            val = 0;
+        } else {
+            val = s->intr_fifo[s->intr_fifo_r].fifo_reg1;
+        }
+        break;
+    case ROOTCFG_RPIFR2:
+        if (s->intr_fifo_w == s->intr_fifo_r) {
+            /* FIFO empty */
+            val = 0;
+        } else {
+            val = s->intr_fifo[s->intr_fifo_r].fifo_reg2;
+        }
+        break;
+    default:
+        val = pci_default_read_config(d, address, len);
+        break;
+    }
+    return val;
+}
+
+static void xilinx_pcie_root_config_write(PCIDevice *d, uint32_t address,
+                                          uint32_t val, int len)
+{
+    XilinxPCIEHost *s = XILINX_PCIE_HOST(OBJECT(d)->parent);
+    switch (address) {
+    case ROOTCFG_INTDEC:
+        xilinx_pcie_update_intr(s, 0, val);
+        break;
+    case ROOTCFG_INTMASK:
+        s->intr_mask = val;
+        xilinx_pcie_update_intr(s, 0, 0);
+        break;
+    case ROOTCFG_RPSCR:
+        s->rpscr &= ~ROOTCFG_RPSCR_BRIDGEEN;
+        s->rpscr |= val & ROOTCFG_RPSCR_BRIDGEEN;
+        memory_region_set_enabled(&s->mmio, val & ROOTCFG_RPSCR_BRIDGEEN);
+
+        if (val & ROOTCFG_INTMASK_INTX) {
+            s->rpscr &= ~ROOTCFG_INTMASK_INTX;
+        }
+        break;
+    case ROOTCFG_RPIFR1:
+    case ROOTCFG_RPIFR2:
+        if (s->intr_fifo_w == s->intr_fifo_r) {
+            /* FIFO empty */
+            return;
+        } else {
+            s->intr_fifo_r = (s->intr_fifo_r + 1) % ARRAY_SIZE(s->intr_fifo);
+        }
+        break;
+    default:
+        pci_default_write_config(d, address, val, len);
+        break;
+    }
+}
+
+static int xilinx_pcie_root_init(PCIDevice *dev)
+{
+    BusState *bus = qdev_get_parent_bus(DEVICE(dev));
+    XilinxPCIEHost *s = XILINX_PCIE_HOST(bus->parent);
+
+    pci_set_word(dev->config + PCI_COMMAND,
+                 PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);
+    pci_set_word(dev->config + PCI_MEMORY_BASE, s->mmio_base >> 16);
+    pci_set_word(dev->config + PCI_MEMORY_LIMIT,
+                 ((s->mmio_base + s->mmio_size - 1) >> 16) & 0xfff0);
+
+    pci_bridge_initfn(dev, TYPE_PCI_BUS);
+
+    if (pcie_endpoint_cap_v1_init(dev, 0x80) < 0) {
+        hw_error("Failed to initialize PCIe capability");
+    }
+
+    return 0;
+}
+
+static void xilinx_pcie_root_class_init(ObjectClass *klass, void *data)
+{
+    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
+    dc->desc = "Xilinx AXI-PCIe Host Bridge";
+    k->vendor_id = PCI_VENDOR_ID_XILINX;
+    k->device_id = 0x7021;
+    k->revision = 0;
+    k->class_id = PCI_CLASS_BRIDGE_HOST;
+    k->is_express = true;
+    k->is_bridge = true;
+    k->init = xilinx_pcie_root_init;
+    k->exit = pci_bridge_exitfn;
+    dc->reset = pci_bridge_reset;
+    k->config_read = xilinx_pcie_root_config_read;
+    k->config_write = xilinx_pcie_root_config_write;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
+}
+
+static const TypeInfo xilinx_pcie_root_info = {
+    .name = TYPE_XILINX_PCIE_ROOT,
+    .parent = TYPE_PCI_BRIDGE,
+    .instance_size = sizeof(XilinxPCIERoot),
+    .class_init = xilinx_pcie_root_class_init,
+};
+
+static void xilinx_pcie_register(void)
+{
+    type_register_static(&xilinx_pcie_root_info);
+    type_register_static(&xilinx_pcie_host_info);
+}
+
+type_init(xilinx_pcie_register)
diff --git a/include/hw/pci-host/xilinx-pcie.h b/include/hw/pci-host/xilinx-pcie.h
new file mode 100644
index 0000000..bec66b2
--- /dev/null
+++ b/include/hw/pci-host/xilinx-pcie.h
@@ -0,0 +1,68 @@
+/*
+ * Xilinx PCIe host controller emulation.
+ *
+ * Copyright (c) 2016 Imagination Technologies
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef HW_XILINX_PCIE_H
+#define HW_XILINX_PCIE_H
+
+#include "hw/hw.h"
+#include "hw/sysbus.h"
+#include "hw/pci/pci.h"
+#include "hw/pci/pci_bus.h"
+#include "hw/pci/pcie_host.h"
+
+#define TYPE_XILINX_PCIE_HOST "xilinx-pcie-host"
+#define XILINX_PCIE_HOST(obj) \
+     OBJECT_CHECK(XilinxPCIEHost, (obj), TYPE_XILINX_PCIE_HOST)
+
+#define TYPE_XILINX_PCIE_ROOT "xilinx-pcie-root"
+#define XILINX_PCIE_ROOT(obj) \
+     OBJECT_CHECK(XilinxPCIERoot, (obj), TYPE_XILINX_PCIE_ROOT)
+
+typedef struct XilinxPCIERoot {
+    PCIBridge parent_obj;
+} XilinxPCIERoot;
+
+typedef struct XilinxPCIEInt {
+    uint32_t fifo_reg1;
+    uint32_t fifo_reg2;
+} XilinxPCIEInt;
+
+typedef struct XilinxPCIEHost {
+    PCIExpressHost parent_obj;
+
+    char name[16];
+
+    uint32_t bus_nr;
+    uint64_t cfg_base, cfg_size;
+    uint64_t mmio_base, mmio_size;
+    bool link_up;
+    qemu_irq irq;
+
+    MemoryRegion mmio, io;
+
+    XilinxPCIERoot root;
+
+    uint32_t intr;
+    uint32_t intr_mask;
+    XilinxPCIEInt intr_fifo[16];
+    unsigned int intr_fifo_r, intr_fifo_w;
+    uint32_t rpscr;
+} XilinxPCIEHost;
+
+#endif /* HW_XILINX_PCIE_H */