hw/arm/fsl-imx8mp: Add PCIe support

Linux checks for the PLLs in the PHY to be locked, so implement a model
emulating that.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Message-id: 20250223114708.1780-9-shentey@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

3 files changed, 102 insertions, 0 deletions

diff --git a/hw/pci-host/Kconfig b/hw/pci-host/Kconfig
index c91880b237..35c0415242 100644
--- a/hw/pci-host/Kconfig
+++ b/hw/pci-host/Kconfig
@@ -99,6 +99,9 @@ config ASTRO
     bool
     select PCI
 
+config PCI_EXPRESS_FSL_IMX8M_PHY
+    bool
+
 config GT64120
     bool
     select PCI
diff --git a/hw/pci-host/fsl_imx8m_phy.c b/hw/pci-host/fsl_imx8m_phy.c
new file mode 100644
index 0000000000..aa304b102b
--- /dev/null
+++ b/hw/pci-host/fsl_imx8m_phy.c
@@ -0,0 +1,98 @@
+/*
+ * i.MX8 PCIe PHY emulation
+ *
+ * Copyright (c) 2025 Bernhard Beschow <shentey@gmail.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "hw/pci-host/fsl_imx8m_phy.h"
+#include "hw/resettable.h"
+#include "migration/vmstate.h"
+
+#define CMN_REG075 0x1d4
+#define ANA_PLL_LOCK_DONE BIT(1)
+#define ANA_PLL_AFC_DONE BIT(0)
+
+static uint64_t fsl_imx8m_pcie_phy_read(void *opaque, hwaddr offset,
+                                        unsigned size)
+{
+    FslImx8mPciePhyState *s = opaque;
+
+    if (offset == CMN_REG075) {
+        return s->data[offset] | ANA_PLL_LOCK_DONE | ANA_PLL_AFC_DONE;
+    }
+
+    return s->data[offset];
+}
+
+static void fsl_imx8m_pcie_phy_write(void *opaque, hwaddr offset,
+                                     uint64_t value, unsigned size)
+{
+    FslImx8mPciePhyState *s = opaque;
+
+    s->data[offset] = value;
+}
+
+static const MemoryRegionOps fsl_imx8m_pcie_phy_ops = {
+    .read = fsl_imx8m_pcie_phy_read,
+    .write = fsl_imx8m_pcie_phy_write,
+    .impl = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 8,
+    },
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static void fsl_imx8m_pcie_phy_realize(DeviceState *dev, Error **errp)
+{
+    FslImx8mPciePhyState *s = FSL_IMX8M_PCIE_PHY(dev);
+
+    memory_region_init_io(&s->iomem, OBJECT(s), &fsl_imx8m_pcie_phy_ops, s,
+                          TYPE_FSL_IMX8M_PCIE_PHY, ARRAY_SIZE(s->data));
+    sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
+}
+
+static void fsl_imx8m_pcie_phy_reset_hold(Object *obj, ResetType type)
+{
+    FslImx8mPciePhyState *s = FSL_IMX8M_PCIE_PHY(obj);
+
+    memset(s->data, 0, sizeof(s->data));
+}
+
+static const VMStateDescription fsl_imx8m_pcie_phy_vmstate = {
+    .name = "fsl-imx8m-pcie-phy",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (const VMStateField[]) {
+        VMSTATE_UINT8_ARRAY(data, FslImx8mPciePhyState,
+                            FSL_IMX8M_PCIE_PHY_DATA_SIZE),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void fsl_imx8m_pcie_phy_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    ResettableClass *rc = RESETTABLE_CLASS(klass);
+
+    dc->realize = fsl_imx8m_pcie_phy_realize;
+    dc->vmsd = &fsl_imx8m_pcie_phy_vmstate;
+    rc->phases.hold = fsl_imx8m_pcie_phy_reset_hold;
+}
+
+static const TypeInfo fsl_imx8m_pcie_phy_types[] = {
+    {
+        .name = TYPE_FSL_IMX8M_PCIE_PHY,
+        .parent = TYPE_SYS_BUS_DEVICE,
+        .instance_size = sizeof(FslImx8mPciePhyState),
+        .class_init = fsl_imx8m_pcie_phy_class_init,
+    }
+};
+
+DEFINE_TYPES(fsl_imx8m_pcie_phy_types)
diff --git a/hw/pci-host/meson.build b/hw/pci-host/meson.build
index 3001e93a43..937a0f72ac 100644
--- a/hw/pci-host/meson.build
+++ b/hw/pci-host/meson.build
@@ -28,6 +28,7 @@ pci_ss.add(when: 'CONFIG_ARTICIA', if_true: files('articia.c'))
 pci_ss.add(when: 'CONFIG_MV64361', if_true: files('mv64361.c'))
 
 # ARM devices
+pci_ss.add(when: 'CONFIG_PCI_EXPRESS_FSL_IMX8M_PHY', if_true: files('fsl_imx8m_phy.c'))
 pci_ss.add(when: 'CONFIG_VERSATILE_PCI', if_true: files('versatile.c'))
 
 # HPPA devices