[PATCH] Add vhost-user-spi and vhost-user-spi-pci devices

[Haixu Cui]

This work is based on the virtio-spi spec, virtio-spi driver introduced by
the following patch series:
- https://github.com/oasis-tcs/virtio-spec/tree/virtio-1.4/device-types/spi
- https://lwn.net/Articles/966715/

To test with rust-vmm vhost-user-spi daemon, start the vhost-daemon firstly:
    vhost-device-spi --socket-path=vspi.sock --socket-count=1 --device 
"/dev/spidev0.0"

Then invoke qemu with the following parameters:
    qemu-system-aarch64 -m 1G \
        -chardev socket,path=/home/root/vspi.sock0,id=vspi \
        -device vhost-user-spi-pci,chardev=vspi,id=spi \
        -object memory-backend-file,id=mem,size=1G,mem-path=/dev/shm,share=on \
        -numa node,memdev=mem
        ...

Signed-off-by: Haixu Cui <quic_haixcui@quicinc.com>
---
 hw/virtio/Kconfig                           |   5 +
 hw/virtio/meson.build                       |   3 +
 hw/virtio/vhost-user-spi-pci.c              |  69 ++++++++
 hw/virtio/vhost-user-spi.c                  |  66 +++++++
 hw/virtio/virtio.c                          |   4 +-
 include/hw/virtio/vhost-user-spi.h          |  25 +++
 include/standard-headers/linux/virtio_ids.h |   1 +
 include/standard-headers/linux/virtio_spi.h | 186 ++++++++++++++++++++
 8 files changed, 358 insertions(+), 1 deletion(-)
 create mode 100644 hw/virtio/vhost-user-spi-pci.c
 create mode 100644 hw/virtio/vhost-user-spi.c
 create mode 100644 include/hw/virtio/vhost-user-spi.h
 create mode 100644 include/standard-headers/linux/virtio_spi.h

diff --git a/hw/virtio/Kconfig b/hw/virtio/Kconfig
index aa63ff7fd4..d5857651e5 100644
--- a/hw/virtio/Kconfig
+++ b/hw/virtio/Kconfig
@@ -110,3 +110,8 @@ config VHOST_USER_SCMI
     bool
     default y
     depends on VIRTIO && VHOST_USER
+
+config VHOST_USER_SPI
+    bool
+    default y
+    depends on VIRTIO && VHOST_USER
diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
index 621fc65454..42296219e5 100644
--- a/hw/virtio/meson.build
+++ b/hw/virtio/meson.build
@@ -26,6 +26,7 @@ if have_vhost
     system_virtio_ss.add(when: 'CONFIG_VHOST_USER_RNG', if_true: 
files('vhost-user-rng.c'))
     system_virtio_ss.add(when: 'CONFIG_VHOST_USER_SND', if_true: 
files('vhost-user-snd.c'))
     system_virtio_ss.add(when: 'CONFIG_VHOST_USER_INPUT', if_true: 
files('vhost-user-input.c'))
+    system_virtio_ss.add(when: 'CONFIG_VHOST_USER_SPI', if_true: 
files('vhost-user-spi.c'))
 
     # PCI Stubs
     system_virtio_ss.add(when: 'CONFIG_VIRTIO_PCI', if_true: 
files('vhost-user-device-pci.c'))
@@ -39,6 +40,8 @@ if have_vhost
                          if_true: files('vhost-user-snd-pci.c'))
     system_virtio_ss.add(when: ['CONFIG_VIRTIO_PCI', 
'CONFIG_VHOST_USER_INPUT'],
                          if_true: files('vhost-user-input-pci.c'))
+    system_virtio_ss.add(when: ['CONFIG_VIRTIO_PCI', 'CONFIG_VHOST_USER_SPI'],
+                         if_true: files('vhost-user-spi-pci.c'))
   endif
   if have_vhost_vdpa
     system_virtio_ss.add(files('vhost-vdpa.c'))
diff --git a/hw/virtio/vhost-user-spi-pci.c b/hw/virtio/vhost-user-spi-pci.c
new file mode 100644
index 0000000000..3565d526af
--- /dev/null
+++ b/hw/virtio/vhost-user-spi-pci.c
@@ -0,0 +1,69 @@
+/*
+ * Vhost-user spi virtio device PCI glue
+ *
+ * Copyright(c) 2024 Qualcomm Innovation Center, Inc. All Rights Reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "hw/qdev-properties.h"
+#include "hw/virtio/vhost-user-spi.h"
+#include "hw/virtio/virtio-pci.h"
+
+struct VHostUserSPIPCI {
+    VirtIOPCIProxy parent_obj;
+    VHostUserSPI vdev;
+};
+
+typedef struct VHostUserSPIPCI VHostUserSPIPCI;
+
+#define TYPE_VHOST_USER_SPI_PCI "vhost-user-spi-pci-base"
+
+DECLARE_INSTANCE_CHECKER(VHostUserSPIPCI, VHOST_USER_SPI_PCI,
+                         TYPE_VHOST_USER_SPI_PCI)
+
+static void vhost_user_spi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
+{
+    VHostUserSPIPCI *dev = VHOST_USER_SPI_PCI(vpci_dev);
+    DeviceState *vdev = DEVICE(&dev->vdev);
+
+    vpci_dev->nvectors = 1;
+    qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
+}
+
+static void vhost_user_spi_pci_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtioPCIClass *k = VIRTIO_PCI_CLASS(klass);
+    PCIDeviceClass *pcidev_k = PCI_DEVICE_CLASS(klass);
+    k->realize = vhost_user_spi_pci_realize;
+    set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
+    pcidev_k->vendor_id = PCI_VENDOR_ID_REDHAT_QUMRANET;
+    pcidev_k->device_id = 0; /* Set by virtio-pci based on virtio id */
+    pcidev_k->revision = 0x00;
+    pcidev_k->class_id = PCI_CLASS_COMMUNICATION_OTHER;
+}
+
+static void vhost_user_spi_pci_instance_init(Object *obj)
+{
+    VHostUserSPIPCI *dev = VHOST_USER_SPI_PCI(obj);
+
+    virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
+                                TYPE_VHOST_USER_SPI);
+}
+
+static const VirtioPCIDeviceTypeInfo vhost_user_spi_pci_info = {
+    .base_name = TYPE_VHOST_USER_SPI_PCI,
+    .non_transitional_name = "vhost-user-spi-pci",
+    .instance_size = sizeof(VHostUserSPIPCI),
+    .instance_init = vhost_user_spi_pci_instance_init,
+    .class_init = vhost_user_spi_pci_class_init,
+};
+
+static void vhost_user_spi_pci_register(void)
+{
+    virtio_pci_types_register(&vhost_user_spi_pci_info);
+}
+
+type_init(vhost_user_spi_pci_register);
diff --git a/hw/virtio/vhost-user-spi.c b/hw/virtio/vhost-user-spi.c
new file mode 100644
index 0000000000..e138b8b53b
--- /dev/null
+++ b/hw/virtio/vhost-user-spi.c
@@ -0,0 +1,66 @@
+/*
+ * Vhost-user spi virtio device
+ *
+ * Copyright(c) 2024 Qualcomm Innovation Center, Inc. All Rights Reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "hw/qdev-properties.h"
+#include "hw/virtio/virtio-bus.h"
+#include "hw/virtio/vhost-user-spi.h"
+#include "qemu/error-report.h"
+#include "standard-headers/linux/virtio_ids.h"
+#include "standard-headers/linux/virtio_spi.h"
+
+static Property vspi_properties[] = {
+    DEFINE_PROP_CHR("chardev", VHostUserBase, chardev),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void vspi_realize(DeviceState *dev, Error **errp)
+{
+    VHostUserBase *vub = VHOST_USER_BASE(dev);
+    VHostUserBaseClass *vubc = VHOST_USER_BASE_GET_CLASS(dev);
+
+    /* Fixed for SPI */
+    vub->virtio_id = VIRTIO_ID_SPI;
+    vub->num_vqs = 1;
+    vub->vq_size = 4;
+    vub->config_size = sizeof(struct virtio_spi_config);
+
+    vubc->parent_realize(dev, errp);
+}
+
+static const VMStateDescription vu_spi_vmstate = {
+    .name = "vhost-user-spi",
+    .unmigratable = 1,
+};
+
+static void vu_spi_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VHostUserBaseClass *vubc = VHOST_USER_BASE_CLASS(klass);
+
+    dc->vmsd = &vu_spi_vmstate;
+    device_class_set_props(dc, vspi_properties);
+    device_class_set_parent_realize(dc, vspi_realize,
+                                    &vubc->parent_realize);
+    set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
+}
+
+static const TypeInfo vu_spi_info = {
+    .name = TYPE_VHOST_USER_SPI,
+    .parent = TYPE_VHOST_USER_BASE,
+    .instance_size = sizeof(VHostUserSPI),
+    .class_init = vu_spi_class_init,
+};
+
+static void vu_spi_register_types(void)
+{
+    type_register_static(&vu_spi_info);
+}
+
+type_init(vu_spi_register_types)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 583a224163..689e2e21e7 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -46,6 +46,7 @@
 #include "standard-headers/linux/virtio_iommu.h"
 #include "standard-headers/linux/virtio_mem.h"
 #include "standard-headers/linux/virtio_vsock.h"
+#include "standard-headers/linux/virtio_spi.h"
 
 /*
  * Maximum size of virtio device config space
@@ -194,7 +195,8 @@ const char *virtio_device_names[] = {
     [VIRTIO_ID_PARAM_SERV] = "virtio-param-serv",
     [VIRTIO_ID_AUDIO_POLICY] = "virtio-audio-pol",
     [VIRTIO_ID_BT] = "virtio-bluetooth",
-    [VIRTIO_ID_GPIO] = "virtio-gpio"
+    [VIRTIO_ID_GPIO] = "virtio-gpio",
+    [VIRTIO_ID_SPI] = "virtio-spi"
 };
 
 static const char *virtio_id_to_name(uint16_t device_id)
diff --git a/include/hw/virtio/vhost-user-spi.h 
b/include/hw/virtio/vhost-user-spi.h
new file mode 100644
index 0000000000..d6967d8431
--- /dev/null
+++ b/include/hw/virtio/vhost-user-spi.h
@@ -0,0 +1,25 @@
+/*
+ * Vhost-user spi virtio device
+ *
+ * Copyright(c) 2024 Qualcomm Innovation Center, Inc. All Rights Reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef QEMU_VHOST_USER_SPI_H
+#define QEMU_VHOST_USER_SPI_H
+
+#include "hw/virtio/virtio.h"
+#include "hw/virtio/vhost.h"
+#include "hw/virtio/vhost-user.h"
+#include "hw/virtio/vhost-user-base.h"
+
+#define TYPE_VHOST_USER_SPI "vhost-user-spi-device"
+
+OBJECT_DECLARE_SIMPLE_TYPE(VHostUserSPI, VHOST_USER_SPI)
+
+struct VHostUserSPI {
+    VHostUserBase parent_obj;
+};
+
+#endif /* QEMU_VHOST_USER_SPI_H */
diff --git a/include/standard-headers/linux/virtio_ids.h 
b/include/standard-headers/linux/virtio_ids.h
index 7aa2eb7662..601d387c5a 100644
--- a/include/standard-headers/linux/virtio_ids.h
+++ b/include/standard-headers/linux/virtio_ids.h
@@ -68,6 +68,7 @@
 #define VIRTIO_ID_AUDIO_POLICY         39 /* virtio audio policy */
 #define VIRTIO_ID_BT                   40 /* virtio bluetooth */
 #define VIRTIO_ID_GPIO                 41 /* virtio gpio */
+#define VIRTIO_ID_SPI                   45 /* virtio spi */
 
 /*
  * Virtio Transitional IDs
diff --git a/include/standard-headers/linux/virtio_spi.h 
b/include/standard-headers/linux/virtio_spi.h
new file mode 100644
index 0000000000..6631827bfa
--- /dev/null
+++ b/include/standard-headers/linux/virtio_spi.h
@@ -0,0 +1,186 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later WITH Linux-syscall-note */
+/*
+ * Definitions for virtio SPI Controller
+ *
+ * Copyright (c) 2021 Intel Corporation. All rights reserved.
+ */
+
+#ifndef _LINUX_VIRTIO_SPI_H
+#define _LINUX_VIRTIO_SPI_H
+
+#include "standard-headers/linux/const.h"
+#include "standard-headers/linux/types.h"
+
+/* Sample data on trailing clock edge */
+#define VIRTIO_SPI_CPHA (1 << 0)
+/* Clock is high when IDLE */
+#define VIRTIO_SPI_CPOL (1 << 1)
+/* Chip Select is active high */
+#define VIRTIO_SPI_CS_HIGH (1 << 2)
+/* Transmit LSB first */
+#define VIRTIO_SPI_MODE_LSB_FIRST (1 << 3)
+/* Loopback mode */
+#define VIRTIO_SPI_MODE_LOOP (1 << 4)
+
+/*
+ * All config fields are read-only for the Virtio SPI driver
+ *
+ * @cs_max_number: maximum number of chipselect the host SPI controller
+ *   supports.
+ * @cs_change_supported: indicates if the host SPI controller supports to 
toggle
+ * chipselect after each transfer in one message:
+ *   0: unsupported, chipselect will be kept in active state throughout the
+ *      message transaction;
+ *   1: supported.
+ *   Note: Message here contains a sequence of SPI transfers.
+ * @tx_nbits_supported: indicates the supported number of bit for writing:
+ *   bit 0: DUAL (2-bit transfer), 1 for supported
+ *   bit 1: QUAD (4-bit transfer), 1 for supported
+ *   bit 2: OCTAL (8-bit transfer), 1 for supported
+ *   other bits are reserved as 0, 1-bit transfer is always supported.
+ * @rx_nbits_supported: indicates the supported number of bit for reading:
+ *   bit 0: DUAL (2-bit transfer), 1 for supported
+ *   bit 1: QUAD (4-bit transfer), 1 for supported
+ *   bit 2: OCTAL (8-bit transfer), 1 for supported
+ *   other bits are reserved as 0, 1-bit transfer is always supported.
+ * @bits_per_word_mask: mask indicating which values of bits_per_word are
+ *   supported. If not set, no limitation for bits_per_word.
+ * @mode_func_supported: indicates the following features are supported or not:
+ *   bit 0-1: CPHA feature
+ *     0b00: invalid, should support as least one CPHA setting
+ *     0b01: supports CPHA=0 only
+ *     0b10: supports CPHA=1 only
+ *     0b11: supports CPHA=0 and CPHA=1.
+ *   bit 2-3: CPOL feature
+ *     0b00: invalid, should support as least one CPOL setting
+ *     0b01: supports CPOL=0 only
+ *     0b10: supports CPOL=1 only
+ *     0b11: supports CPOL=0 and CPOL=1.
+ *   bit 4: chipselect active high feature, 0 for unsupported and 1 for
+ *     supported, chipselect active low should always be supported.
+ *   bit 5: LSB first feature, 0 for unsupported and 1 for supported,
+ *     MSB first should always be supported.
+ *   bit 6: loopback mode feature, 0 for unsupported and 1 for supported,
+ *     normal mode should always be supported.
+ * @max_freq_hz: the maximum clock rate supported in Hz unit, 0 means no
+ *   limitation for transfer speed.
+ * @max_word_delay_ns: the maximum word delay supported in ns unit,
+ *   0 means word delay feature is unsupported.
+ *   Note: Just as one message contains a sequence of transfers,
+ *         one transfer may contain a sequence of words.
+ * @max_cs_setup_ns: the maximum delay supported after chipselect is asserted,
+ *   in ns unit, 0 means delay is not supported to introduce after chipselect 
is
+ *   asserted.
+ * @max_cs_hold_ns: the maximum delay supported before chipselect is 
deasserted,
+ *   in ns unit, 0 means delay is not supported to introduce before chipselect
+ *   is deasserted.
+ * @max_cs_incative_ns: maximum delay supported after chipselect is deasserted,
+ *   in ns unit, 0 means delay is not supported to introduce after chipselect 
is
+ *   deasserted.
+ */
+struct virtio_spi_config {
+       /* # of /dev/spidev<bus_num>.CS with CS=0..chip_select_max_number -1 */
+        uint8_t cs_max_number;
+        uint8_t cs_change_supported;
+#define VIRTIO_SPI_RX_TX_SUPPORT_DUAL (1 << 0)
+#define VIRTIO_SPI_RX_TX_SUPPORT_QUAD (1 << 1)
+#define VIRTIO_SPI_RX_TX_SUPPORT_OCTAL (1 << 2)
+        uint8_t tx_nbits_supported;
+        uint8_t rx_nbits_supported;
+        uint32_t bits_per_word_mask;
+#define VIRTIO_SPI_MF_SUPPORT_CPHA_0 (1 << 0)
+#define VIRTIO_SPI_MF_SUPPORT_CPHA_1 (1 << 1)
+#define VIRTIO_SPI_MF_SUPPORT_CPOL_0 (1 << 2)
+#define VIRTIO_SPI_MF_SUPPORT_CPOL_1 (1 << 3)
+#define VIRTIO_SPI_MF_SUPPORT_CS_HIGH (1 << 4)
+#define VIRTIO_SPI_MF_SUPPORT_LSB_FIRST (1 << 5)
+#define VIRTIO_SPI_MF_SUPPORT_LOOPBACK (1 << 6)
+        uint32_t mode_func_supported;
+        uint32_t max_freq_hz;
+        uint32_t max_word_delay_ns;
+        uint32_t max_cs_setup_ns;
+        uint32_t max_cs_hold_ns;
+        uint32_t max_cs_inactive_ns;
+};
+
+/*
+ * @chip_select_id: chipselect index the SPI transfer used.
+ *
+ * @bits_per_word: the number of bits in each SPI transfer word.
+ *
+ * @cs_change: whether to deselect device after finishing this transfer
+ *     before starting the next transfer, 0 means cs keep asserted and
+ *     1 means cs deasserted then asserted again.
+ *
+ * @tx_nbits: bus width for write transfer.
+ *     0,1: bus width is 1, also known as SINGLE
+ *     2  : bus width is 2, also known as DUAL
+ *     4  : bus width is 4, also known as QUAD
+ *     8  : bus width is 8, also known as OCTAL
+ *     other values are invalid.
+ *
+ * @rx_nbits: bus width for read transfer.
+ *     0,1: bus width is 1, also known as SINGLE
+ *     2  : bus width is 2, also known as DUAL
+ *     4  : bus width is 4, also known as QUAD
+ *     8  : bus width is 8, also known as OCTAL
+ *     other values are invalid.
+ *
+ * @reserved: for future use.
+ *
+ * @mode: SPI transfer mode.
+ *     bit 0: CPHA, determines the timing (i.e. phase) of the data
+ *         bits relative to the clock pulses.For CPHA=0, the
+ *         "out" side changes the data on the trailing edge of the
+ *         preceding clock cycle, while the "in" side captures the data
+ *         on (or shortly after) the leading edge of the clock cycle.
+ *         For CPHA=1, the "out" side changes the data on the leading
+ *         edge of the current clock cycle, while the "in" side
+ *         captures the data on (or shortly after) the trailing edge of
+ *         the clock cycle.
+ *     bit 1: CPOL, determines the polarity of the clock. CPOL=0 is a
+ *         clock which idles at 0, and each cycle consists of a pulse
+ *         of 1. CPOL=1 is a clock which idles at 1, and each cycle
+ *         consists of a pulse of 0.
+ *     bit 2: CS_HIGH, if 1, chip select active high, else active low.
+ *     bit 3: LSB_FIRST, determines per-word bits-on-wire, if 0, MSB
+ *         first, else LSB first.
+ *     bit 4: LOOP, loopback mode.
+ *
+ * @freq: the transfer speed in Hz.
+ *
+ * @word_delay_ns: delay to be inserted between consecutive words of a
+ *     transfer, in ns unit.
+ *
+ * @cs_setup_ns: delay to be introduced after CS is asserted, in ns
+ *     unit.
+ *
+ * @cs_delay_hold_ns: delay to be introduced before CS is deasserted
+ *     for each transfer, in ns unit.
+ *
+ * @cs_change_delay_inactive_ns: delay to be introduced after CS is
+ *     deasserted and before next asserted, in ns unit.
+ */
+struct spi_transfer_head {
+        uint8_t chip_select_id;
+        uint8_t bits_per_word;
+        uint8_t cs_change;
+        uint8_t tx_nbits;
+        uint8_t rx_nbits;
+        uint8_t reserved[3];
+        uint32_t mode;
+        uint32_t freq;
+        uint32_t word_delay_ns;
+        uint32_t cs_setup_ns;
+        uint32_t cs_delay_hold_ns;
+        uint32_t cs_change_delay_inactive_ns;
+};
+
+struct spi_transfer_result {
+#define VIRTIO_SPI_TRANS_OK 0
+#define VIRTIO_SPI_PARAM_ERR 1
+#define VIRTIO_SPI_TRANS_ERR 2
+       uint8_t status;
+};
+
+#endif /* _LINUX_VIRTIO_SPI_H */
-- 
2.34.1