drivers/net/mctp/Kconfig | 10 + drivers/net/mctp/Makefile | 1 + drivers/net/mctp/mctp-pcie-vdm.c | 673 +++++++++++++++++++++++++++++++ include/linux/mctp-pcie-vdm.h | 42 ++ 4 files changed, 726 insertions(+) create mode 100644 drivers/net/mctp/mctp-pcie-vdm.c create mode 100644 include/linux/mctp-pcie-vdm.h
Add an implementation for DMTF DSP0238 MCTP PCIe VDM transport spec.
Introduce struct mctp_pcie_vdm_dev to represent each PCIe VDM
interface and its send/receive operations. Register a
net_device with the MCTP core so packets traverse the standard
networking socket API.
Because there is no generic PCIe VDM bus framework in-tree, this
driver provides a transport interface for lower layers to
implement vendor-specific read/write callbacks.
TX path uses a dedicated kernel thread and ptr_ring: skbs queued by the
MCTP stack are enqueued on the ring and processed in-thread context.
RX path employs a workqueue; the lower layer notifies availability, and
the work handler drains packets until the receive callback returns an
ERR_PTR, avoiding per-packet notifications.
Signed-off-by: aspeedyh <yh_chung@aspeedtech.com>
---
drivers/net/mctp/Kconfig | 10 +
drivers/net/mctp/Makefile | 1 +
drivers/net/mctp/mctp-pcie-vdm.c | 673 +++++++++++++++++++++++++++++++
include/linux/mctp-pcie-vdm.h | 42 ++
4 files changed, 726 insertions(+)
create mode 100644 drivers/net/mctp/mctp-pcie-vdm.c
create mode 100644 include/linux/mctp-pcie-vdm.h
diff --git a/drivers/net/mctp/Kconfig b/drivers/net/mctp/Kconfig
index cf325ab0b1ef..3355613bb04b 100644
--- a/drivers/net/mctp/Kconfig
+++ b/drivers/net/mctp/Kconfig
@@ -57,6 +57,16 @@ config MCTP_TRANSPORT_USB
MCTP-over-USB interfaces are peer-to-peer, so each interface
represents a physical connection to one remote MCTP endpoint.
+config MCTP_TRANSPORT_PCIE_VDM
+ tristate "MCTP PCIe VDM transport"
+ depends on PCI
+ select MCTP_FLOWS
+ help
+ Provides a driver to access MCTP devices over PCIe VDM transport,
+ from DMTF specification DSP0238.
+ A MCTP protocol network device is created for each PCIe VDM device
+ that registers to this driver.
+
endmenu
endif
diff --git a/drivers/net/mctp/Makefile b/drivers/net/mctp/Makefile
index c36006849a1e..4acd04d7eb32 100644
--- a/drivers/net/mctp/Makefile
+++ b/drivers/net/mctp/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_MCTP_SERIAL) += mctp-serial.o
obj-$(CONFIG_MCTP_TRANSPORT_I2C) += mctp-i2c.o
obj-$(CONFIG_MCTP_TRANSPORT_I3C) += mctp-i3c.o
obj-$(CONFIG_MCTP_TRANSPORT_USB) += mctp-usb.o
+obj-$(CONFIG_MCTP_TRANSPORT_PCIE_VDM) += mctp-pcie-vdm.o
diff --git a/drivers/net/mctp/mctp-pcie-vdm.c b/drivers/net/mctp/mctp-pcie-vdm.c
new file mode 100644
index 000000000000..7ac4d3f55992
--- /dev/null
+++ b/drivers/net/mctp/mctp-pcie-vdm.c
@@ -0,0 +1,673 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * mctp-pcie-vdm.c - MCTP-over-PCIe-VDM (DMTF DSP0238) transport binding driver.
+ *
+ * DSP0238 is available at:
+ * https://www.dmtf.org/sites/default/files/standards/documents/DSP0238_1.2.0.pdf
+ *
+ */
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/byteorder/generic.h>
+#include <linux/dynamic_debug.h>
+#include <linux/fs.h>
+#include <linux/hashtable.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/kthread.h>
+#include <linux/list.h>
+#include <linux/mctp-pcie-vdm.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/netdevice.h>
+#include <linux/notifier.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/printk.h>
+#include <linux/ptr_ring.h>
+#include <linux/skbuff.h>
+#include <linux/stddef.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+#include <net/mctp.h>
+#include <net/mctpdevice.h>
+
+#define MCTP_PCIE_VDM_MIN_MTU 64
+#define MCTP_PCIE_VDM_MAX_MTU 512
+/* 16byte */
+#define MCTP_PCIE_VDM_HDR_SIZE 16
+#define MCTP_PAYLOAD_IC_TYPE_SIZE 1
+#define MCTP_RECEIVE_PKT_TIMEOUT_MS 5
+
+#define MCTP_PCIE_VDM_NET_DEV_TX_QUEUE_LEN 1100
+#define MCTP_PCIE_VDM_DEV_TX_QUEUE_SIZE 64
+
+#define MCTP_PCIE_VDM_FMT_4DW 0x3
+#define MCTP_PCIE_VDM_TYPE_MSG 0x10
+#define MCTP_PCIE_VDM_CODE 0x0
+/* PCIe VDM message code */
+#define MCTP_PCIE_VDM_MSG_CODE 0x7F
+#define MCTP_PCIE_VDM_VENDOR_ID 0x1AB4
+/* MCTP message type */
+#define MCTP_MSG_TYPE_MASK GENMASK(6, 0)
+#define MCTP_PCIE_VDM_MSG_TYPE 0x7E
+#define MCTP_CONTROL_MSG_TYPE 0x00
+
+#define MCTP_CTRL_MSG_RQDI_REQ 0x80
+#define MCTP_CTRL_MSG_RQDI_RSP 0x00
+
+#define MCTP_CTRL_MSG_RQDI_REQ_DATA_OFFSET 3
+#define MCTP_CTRL_MSG_RQDI_RSP_DATA_OFFSET 4
+
+#define MCTP_PCIE_SWAP_NET_ENDIAN(arr, len) \
+ do { \
+ u32 *p = (u32 *)(arr); \
+ for (int i = 0; i < (len); i++) { \
+ p[i] = htonl(p[i]); \
+ } \
+ } while (0)
+
+#define MCTP_PCIE_SWAP_LITTLE_ENDIAN(arr, len) \
+ do { \
+ u32 *p = (u32 *)(arr); \
+ for (int i = 0; i < (len); i++) { \
+ p[i] = ntohl(p[i]); \
+ p[i] = cpu_to_le32(p[i]); \
+ } \
+ } while (0)
+
+enum mctp_pcie_vdm_route_type {
+ MCTP_PCIE_VDM_ROUTE_TO_RC = 0,
+ MCTP_PCIE_VDM_ROUTE_BY_ID = 2,
+ MCTP_PCIE_VDM_BROADCAST_FROM_RC = 3,
+};
+
+enum mctp_ctrl_command_code {
+ MCTP_CTRL_CMD_SET_ENDPOINT_ID = 0x01,
+ MCTP_CTRL_CMD_GET_ENDPOINT_ID = 0x02,
+ MCTP_CTRL_CMD_PREPARE_ENDPOINT_DISCOVERY = 0x0B,
+ MCTP_CTRL_CMD_ENDPOINT_DISCOVERY = 0x0C,
+ MCTP_CTRL_CMD_DISCOVERY_NOTIFY = 0x0D
+};
+
+struct mctp_ctrl_msg_hdr {
+ u8 ctrl_msg_class;
+ u8 command_code;
+};
+
+struct mctp_pcie_vdm_hdr {
+ u32 length : 10, rsvd0 : 2, attr : 2, ep : 1, td : 1, rsvd1 : 4, tc : 3,
+ rsvd2 : 1, route_type : 5, fmt : 2, rsvd3 : 1;
+ u8 msg_code;
+ u8 tag_vdm_code : 4, tag_pad_len : 2, tag_rsvd : 2;
+ u16 pci_req_id;
+ u16 pci_vendor_id;
+ u16 pci_target_id;
+};
+
+struct mctp_pcie_vdm_route_info {
+ u8 eid;
+ u8 dirty;
+ u16 bdf_addr;
+ struct hlist_node hnode;
+};
+
+struct mctp_pcie_vdm_dev {
+ struct device *dev;
+ struct net_device *ndev;
+ struct task_struct *tx_thread;
+ wait_queue_head_t tx_wait;
+ struct work_struct rx_work;
+ struct ptr_ring tx_queue;
+ struct list_head list;
+ /* each network may have at most 256 EIDs */
+ DECLARE_HASHTABLE(route_table, 8);
+ const struct mctp_pcie_vdm_ops *callback_ops;
+};
+
+/* mutex for vdm_devs add/delete */
+DEFINE_MUTEX(mctp_pcie_vdm_dev_mutex);
+LIST_HEAD(mctp_pcie_vdm_devs);
+struct workqueue_struct *mctp_pcie_vdm_wq;
+
+static const struct mctp_pcie_vdm_hdr mctp_pcie_vdm_hdr_template = {
+ .fmt = MCTP_PCIE_VDM_FMT_4DW,
+ .route_type = MCTP_PCIE_VDM_TYPE_MSG | MCTP_PCIE_VDM_ROUTE_BY_ID,
+ .tag_vdm_code = MCTP_PCIE_VDM_CODE,
+ .msg_code = MCTP_PCIE_VDM_MSG_CODE,
+ .pci_vendor_id = MCTP_PCIE_VDM_VENDOR_ID,
+ .attr = 0,
+};
+
+static void mctp_pcie_vdm_display_skb_buff_data(struct sk_buff *skb)
+{
+ int i = 0;
+
+ while ((i + 4) < skb->len) {
+ pr_debug("%02x %02x %02x %02x\n", skb->data[i],
+ skb->data[i + 1], skb->data[i + 2], skb->data[i + 3]);
+ i += 4;
+ }
+
+ char buf[16] = { 0 };
+ char *p = buf;
+
+ while (i < skb->len) {
+ p += snprintf(p, sizeof(buf) - (p - buf), "%02x ",
+ skb->data[i]);
+ i++;
+ }
+ pr_debug("%s\n", buf);
+}
+
+static void mctp_pcie_vdm_update_route_table(struct mctp_pcie_vdm_dev *vdm_dev,
+ u8 eid, u16 bdf)
+{
+ if (eid == 0x00 || eid == 0xFF)
+ return;
+
+ bool exist = false;
+ struct mctp_pcie_vdm_route_info *route;
+
+ hash_for_each_possible(vdm_dev->route_table, route, hnode, eid) {
+ pr_debug("%s: route table eid %d maps to %d", __func__,
+ route->eid, route->bdf_addr);
+ if (route->eid == eid) {
+ exist = true;
+ route->bdf_addr = bdf;
+ break;
+ }
+ }
+
+ if (!exist) {
+ route = kmalloc(sizeof(*route), GFP_KERNEL);
+ route->bdf_addr = bdf;
+ route->eid = eid;
+ route->dirty = 0;
+
+ hash_add(vdm_dev->route_table, &route->hnode, route->eid);
+ pr_debug("%s: not found, add map eid %d to bdf 0x%x", __func__,
+ eid, bdf);
+ }
+}
+
+static void mctp_pcie_vdm_ctrl_msg_handler(struct mctp_pcie_vdm_dev *vdm_dev,
+ u8 *packet)
+{
+ u8 message_type =
+ FIELD_GET(MCTP_MSG_TYPE_MASK, packet[MCTP_PCIE_VDM_HDR_SIZE]);
+
+ if (message_type != MCTP_CONTROL_MSG_TYPE)
+ return;
+
+ struct mctp_ctrl_msg_hdr *ctrl_hdr =
+ (struct mctp_ctrl_msg_hdr *)(&packet[MCTP_PCIE_VDM_HDR_SIZE + 1]);
+
+ /* host endian expected */
+ struct mctp_pcie_vdm_hdr *hdr = (struct mctp_pcie_vdm_hdr *)packet;
+
+ switch (ctrl_hdr->command_code) {
+ case MCTP_CTRL_CMD_SET_ENDPOINT_ID:
+ if (ctrl_hdr->ctrl_msg_class == MCTP_CTRL_MSG_RQDI_REQ) {
+ /* EID placed at byte2 of SET EID REQ DATA */
+ u8 dst_eid =
+ packet[MCTP_PCIE_VDM_HDR_SIZE +
+ MCTP_CTRL_MSG_RQDI_REQ_DATA_OFFSET + 1];
+ u16 dst_bdf = hdr->pci_target_id;
+
+ mctp_pcie_vdm_update_route_table(vdm_dev, dst_eid,
+ dst_bdf);
+ }
+ break;
+ case MCTP_CTRL_CMD_GET_ENDPOINT_ID:
+ if (ctrl_hdr->ctrl_msg_class == MCTP_CTRL_MSG_RQDI_RSP) {
+ /* EID placed at byte2 of GET EID RSP DATA */
+ u8 target_eid =
+ packet[MCTP_PCIE_VDM_HDR_SIZE +
+ MCTP_CTRL_MSG_RQDI_RSP_DATA_OFFSET + 1];
+ u16 src_bdf = hdr->pci_req_id;
+
+ mctp_pcie_vdm_update_route_table(vdm_dev, target_eid,
+ src_bdf);
+ }
+ break;
+ case MCTP_CTRL_CMD_DISCOVERY_NOTIFY:
+ hdr->pci_target_id = 0x0000;
+ /* default use MCTP_PCIE_VDM_ROUTE_BY_ID, so no need to handle RSP class */
+ if (ctrl_hdr->ctrl_msg_class == MCTP_CTRL_MSG_RQDI_REQ) {
+ hdr->route_type = MCTP_PCIE_VDM_TYPE_MSG |
+ MCTP_PCIE_VDM_ROUTE_TO_RC;
+ }
+ break;
+ case MCTP_CTRL_CMD_PREPARE_ENDPOINT_DISCOVERY:
+ case MCTP_CTRL_CMD_ENDPOINT_DISCOVERY:
+ if (ctrl_hdr->ctrl_msg_class == MCTP_CTRL_MSG_RQDI_REQ) {
+ hdr->route_type = MCTP_PCIE_VDM_TYPE_MSG |
+ MCTP_PCIE_VDM_BROADCAST_FROM_RC;
+ hdr->pci_target_id = 0xFFFF;
+ } else if (ctrl_hdr->ctrl_msg_class == MCTP_CTRL_MSG_RQDI_RSP) {
+ hdr->route_type = MCTP_PCIE_VDM_TYPE_MSG |
+ MCTP_PCIE_VDM_ROUTE_TO_RC;
+ }
+ break;
+ default:
+ /* Unknown command code or not supported currently */
+ break;
+ }
+}
+
+static netdev_tx_t mctp_pcie_vdm_start_xmit(struct sk_buff *skb,
+ struct net_device *ndev)
+{
+ struct mctp_pcie_vdm_dev *vdm_dev = netdev_priv(ndev);
+
+ pr_debug("%s: skb len %u\n", __func__, skb->len);
+
+ netdev_tx_t ret;
+
+ if (ptr_ring_full(&vdm_dev->tx_queue)) {
+ pr_debug("%s: failed to send packet, buffer full\n", __func__);
+ netif_stop_queue(ndev);
+
+ ret = NETDEV_TX_BUSY;
+ } else {
+ int reason = ptr_ring_produce_bh(&vdm_dev->tx_queue, skb);
+
+ if (reason) {
+ pr_err("%s: failed to produce skb to tx queue, reason %d\n",
+ __func__, reason);
+ ret = NETDEV_TX_BUSY;
+ } else {
+ ret = NETDEV_TX_OK;
+ }
+ }
+
+ wake_up(&vdm_dev->tx_wait);
+
+ return ret;
+}
+
+static void mctp_pcie_vdm_xmit(struct mctp_pcie_vdm_dev *vdm_dev,
+ struct sk_buff *skb)
+{
+ struct net_device_stats *stats;
+ struct mctp_pcie_vdm_hdr *hdr;
+ u8 *hdr_byte;
+ u8 message_type;
+ u16 payload_len_dw;
+ u16 payload_len_byte;
+ int rc;
+
+ stats = &vdm_dev->ndev->stats;
+ hdr = (struct mctp_pcie_vdm_hdr *)skb->data;
+ hdr_byte = skb->data;
+ payload_len_dw = (ALIGN(skb->len, sizeof(u32)) - MCTP_PCIE_VDM_HDR_SIZE) / sizeof(u32);
+ payload_len_byte = skb->len - MCTP_PCIE_VDM_HDR_SIZE;
+ message_type = FIELD_GET(MCTP_MSG_TYPE_MASK, hdr_byte[MCTP_PCIE_VDM_HDR_SIZE]);
+
+ if (message_type == MCTP_CONTROL_MSG_TYPE) {
+ mctp_pcie_vdm_ctrl_msg_handler(vdm_dev, hdr_byte);
+ } else {
+ if (hdr->route_type ==
+ (MCTP_PCIE_VDM_TYPE_MSG | MCTP_PCIE_VDM_ROUTE_BY_ID)) {
+ struct mctp_pcie_vdm_route_info *route;
+ bool exist = false;
+ u16 bdf = 0x00;
+ u8 dst_eid =
+ FIELD_GET(GENMASK(15, 8),
+ *((u32 *)skb->data +
+ sizeof(struct mctp_pcie_vdm_hdr) /
+ sizeof(u32)));
+
+ hash_for_each_possible(vdm_dev->route_table, route,
+ hnode, dst_eid) {
+ if (route->eid == dst_eid) {
+ exist = true;
+ bdf = route->bdf_addr;
+ hdr->pci_target_id = bdf;
+ break;
+ }
+ }
+ if (exist)
+ pr_debug("%s fill bdf 0x%x to eid %d", __func__,
+ bdf, dst_eid);
+ }
+ }
+
+ hdr->length = payload_len_dw;
+ hdr->tag_pad_len =
+ ALIGN(payload_len_byte, sizeof(u32)) - payload_len_byte;
+ pr_debug("%s: skb len %d pad len %d\n", __func__, skb->len,
+ hdr->tag_pad_len);
+ MCTP_PCIE_SWAP_NET_ENDIAN((u32 *)hdr,
+ sizeof(struct mctp_pcie_vdm_hdr) / sizeof(u32));
+
+ mctp_pcie_vdm_display_skb_buff_data(skb);
+ rc = vdm_dev->callback_ops->send_packet(vdm_dev->dev, skb->data,
+ payload_len_dw * sizeof(u32));
+
+ if (rc) {
+ pr_err("%s: failed to send packet, rc %d\n", __func__, rc);
+ stats->tx_errors++;
+ return;
+ }
+ stats->tx_packets++;
+ stats->tx_bytes += (skb->len - sizeof(struct mctp_pcie_vdm_hdr));
+}
+
+static int mctp_pcie_vdm_tx_thread(void *data)
+{
+ struct mctp_pcie_vdm_dev *vdm_dev = data;
+
+ for (;;) {
+ wait_event_idle(vdm_dev->tx_wait,
+ __ptr_ring_peek(&vdm_dev->tx_queue) ||
+ kthread_should_stop());
+
+ if (kthread_should_stop())
+ break;
+
+ while (__ptr_ring_peek(&vdm_dev->tx_queue)) {
+ struct sk_buff *skb;
+
+ skb = ptr_ring_consume(&vdm_dev->tx_queue);
+
+ if (skb) {
+ mctp_pcie_vdm_xmit(vdm_dev, skb);
+ kfree_skb(skb);
+ }
+ }
+ if (netif_queue_stopped(vdm_dev->ndev))
+ netif_wake_queue(vdm_dev->ndev);
+ }
+
+ pr_debug("%s stopping\n", __func__);
+ return 0;
+}
+
+static void mctp_pcie_vdm_rx_work_handler(struct work_struct *work)
+{
+ struct mctp_pcie_vdm_dev *vdm_dev;
+ u8 *packet;
+
+ vdm_dev = container_of(work, struct mctp_pcie_vdm_dev, rx_work);
+ packet = vdm_dev->callback_ops->recv_packet(vdm_dev->dev);
+
+ while (!IS_ERR(packet)) {
+ MCTP_PCIE_SWAP_LITTLE_ENDIAN((u32 *)packet,
+ sizeof(struct mctp_pcie_vdm_hdr) / sizeof(u32));
+ struct mctp_pcie_vdm_hdr *vdm_hdr = (struct mctp_pcie_vdm_hdr *)packet;
+ struct mctp_skb_cb *cb;
+ struct net_device_stats *stats;
+ struct sk_buff *skb;
+ u16 len;
+ int net_status;
+
+ stats = &vdm_dev->ndev->stats;
+ len = vdm_hdr->length * sizeof(u32) -
+ vdm_hdr->tag_pad_len;
+ len += MCTP_PCIE_VDM_HDR_SIZE;
+ skb = netdev_alloc_skb(vdm_dev->ndev, len);
+ pr_debug("%s: received packet size: %d\n", __func__,
+ len);
+
+ if (!skb) {
+ stats->rx_errors++;
+ pr_err("%s: failed to alloc skb\n", __func__);
+ continue;
+ }
+
+ skb->protocol = htons(ETH_P_MCTP);
+ /* put data into tail sk buff */
+ skb_put_data(skb, packet, len);
+ /* remove first 12bytes PCIe VDM header */
+ skb_pull(skb, sizeof(struct mctp_pcie_vdm_hdr));
+ mctp_pcie_vdm_display_skb_buff_data(skb);
+
+ cb = __mctp_cb(skb);
+ cb->halen = 2; // BDF size is 2 bytes
+ memcpy(cb->haddr, &vdm_hdr->pci_req_id, cb->halen);
+
+ net_status = netif_rx(skb);
+ if (net_status == NET_RX_SUCCESS) {
+ stats->rx_packets++;
+ stats->rx_bytes += skb->len;
+ } else {
+ stats->rx_dropped++;
+ }
+
+ mctp_pcie_vdm_ctrl_msg_handler(vdm_dev, packet);
+
+ if (vdm_hdr->route_type ==
+ (MCTP_PCIE_VDM_TYPE_MSG |
+ MCTP_PCIE_VDM_ROUTE_BY_ID)) {
+ u32 mctp_hdr;
+ u16 bdf;
+ u8 src_eid;
+
+ bdf = vdm_hdr->pci_req_id;
+ mctp_hdr = *((u32 *)packet +
+ sizeof(struct mctp_pcie_vdm_hdr) /
+ sizeof(u32));
+ MCTP_PCIE_SWAP_LITTLE_ENDIAN(&mctp_hdr, 1);
+ src_eid = FIELD_GET(GENMASK(15, 8), mctp_hdr);
+
+ mctp_pcie_vdm_update_route_table(vdm_dev,
+ src_eid, bdf);
+ }
+
+ vdm_dev->callback_ops->free_packet(packet);
+ packet = vdm_dev->callback_ops->recv_packet(vdm_dev->dev);
+ }
+}
+
+static int mctp_pcie_vdm_add_mctp_dev(struct mctp_pcie_vdm_dev *vdm_dev)
+{
+ hash_init(vdm_dev->route_table);
+ INIT_LIST_HEAD(&vdm_dev->list);
+ init_waitqueue_head(&vdm_dev->tx_wait);
+ ptr_ring_init(&vdm_dev->tx_queue, MCTP_PCIE_VDM_DEV_TX_QUEUE_SIZE,
+ GFP_KERNEL);
+ vdm_dev->tx_thread = kthread_run(mctp_pcie_vdm_tx_thread, vdm_dev,
+ "mctp_pcie_vdm_tx_thread");
+ INIT_WORK(&vdm_dev->rx_work, mctp_pcie_vdm_rx_work_handler);
+
+ mutex_lock(&mctp_pcie_vdm_dev_mutex);
+ list_add_tail(&vdm_dev->list, &mctp_pcie_vdm_devs);
+ mutex_unlock(&mctp_pcie_vdm_dev_mutex);
+ return 0;
+}
+
+static void mctp_pcie_vdm_uninit(struct net_device *ndev)
+{
+ struct mctp_pcie_vdm_dev *vdm_dev;
+
+ struct mctp_pcie_vdm_route_info *route;
+ struct hlist_node *tmp;
+ int bkt;
+
+ pr_debug("%s: uninitializing vdm_dev %s\n", __func__,
+ vdm_dev->ndev->name);
+
+ vdm_dev = netdev_priv(ndev);
+ vdm_dev->callback_ops->uninit(vdm_dev->dev);
+
+ hash_for_each_safe(vdm_dev->route_table, bkt, tmp, route, hnode) {
+ hash_del(&route->hnode);
+ kfree(route);
+ }
+
+ if (vdm_dev->tx_thread) {
+ kthread_stop(vdm_dev->tx_thread);
+ vdm_dev->tx_thread = NULL;
+ }
+
+ if (mctp_pcie_vdm_wq) {
+ cancel_work_sync(&vdm_dev->rx_work);
+ flush_workqueue(mctp_pcie_vdm_wq);
+ destroy_workqueue(mctp_pcie_vdm_wq);
+ mctp_pcie_vdm_wq = NULL;
+ }
+
+ while (__ptr_ring_peek(&vdm_dev->tx_queue)) {
+ struct sk_buff *skb;
+
+ skb = ptr_ring_consume(&vdm_dev->tx_queue);
+
+ if (skb)
+ kfree_skb(skb);
+ }
+
+ mutex_lock(&mctp_pcie_vdm_dev_mutex);
+ list_del(&vdm_dev->list);
+ mutex_unlock(&mctp_pcie_vdm_dev_mutex);
+}
+
+static int mctp_pcie_vdm_hdr_create(struct sk_buff *skb,
+ struct net_device *ndev,
+ unsigned short type, const void *daddr,
+ const void *saddr, unsigned int len)
+{
+ struct mctp_pcie_vdm_hdr *hdr =
+ (struct mctp_pcie_vdm_hdr *)skb_push(skb, sizeof(*hdr));
+
+ pr_debug("%s type %d len %d\n", __func__, type, len);
+ memcpy(hdr, &mctp_pcie_vdm_hdr_template, sizeof(*hdr));
+ if (daddr) {
+ pr_debug("%s dst addr %d\n", __func__, *(u16 *)daddr);
+ hdr->pci_target_id = *(u16 *)daddr;
+ }
+
+ if (saddr) {
+ pr_debug("%s src addr %d\n", __func__, *(u16 *)saddr);
+ hdr->pci_req_id = *(u16 *)saddr;
+ }
+
+ return 0;
+}
+
+static const struct net_device_ops mctp_pcie_vdm_net_ops = {
+ .ndo_start_xmit = mctp_pcie_vdm_start_xmit,
+ .ndo_uninit = mctp_pcie_vdm_uninit,
+};
+
+static const struct header_ops mctp_pcie_vdm_net_hdr_ops = {
+ .create = mctp_pcie_vdm_hdr_create,
+};
+
+static void mctp_pcie_vdm_net_setup(struct net_device *ndev)
+{
+ ndev->type = ARPHRD_MCTP;
+
+ ndev->mtu = MCTP_PCIE_VDM_MIN_MTU;
+ ndev->min_mtu = MCTP_PCIE_VDM_MIN_MTU;
+ ndev->max_mtu = MCTP_PCIE_VDM_MAX_MTU;
+ ndev->tx_queue_len = MCTP_PCIE_VDM_NET_DEV_TX_QUEUE_LEN;
+ ndev->addr_len = 2; //PCIe bdf is 2 bytes
+ ndev->hard_header_len = sizeof(struct mctp_pcie_vdm_hdr);
+
+ ndev->netdev_ops = &mctp_pcie_vdm_net_ops;
+ ndev->header_ops = &mctp_pcie_vdm_net_hdr_ops;
+}
+
+static int mctp_pcie_vdm_add_net_dev(struct net_device **dev)
+{
+ struct net_device *ndev = alloc_netdev(sizeof(struct mctp_pcie_vdm_dev),
+ "mctppci%d", NET_NAME_UNKNOWN,
+ mctp_pcie_vdm_net_setup);
+
+ if (!ndev) {
+ pr_err("%s: failed to allocate net device\n", __func__);
+ return -ENOMEM;
+ }
+ dev_net_set(ndev, current->nsproxy->net_ns);
+
+ *dev = ndev;
+ int rc;
+
+ rc = mctp_register_netdev(ndev, NULL, MCTP_PHYS_BINDING_PCIE_VDM);
+ if (rc) {
+ pr_err("%s: failed to register net device\n", __func__);
+ free_netdev(ndev);
+ return rc;
+ }
+ return rc;
+}
+
+struct mctp_pcie_vdm_dev *mctp_pcie_vdm_add_dev(struct device *dev,
+ const struct mctp_pcie_vdm_ops *ops)
+{
+ struct net_device *ndev;
+ int rc;
+
+ rc = mctp_pcie_vdm_add_net_dev(&ndev);
+ if (rc) {
+ pr_err("%s: failed to add net device\n", __func__);
+ return ERR_PTR(rc);
+ }
+
+ struct mctp_pcie_vdm_dev *vdm_dev;
+
+ vdm_dev = netdev_priv(ndev);
+ vdm_dev->ndev = ndev;
+ vdm_dev->dev = dev;
+ vdm_dev->callback_ops = ops;
+
+ rc = mctp_pcie_vdm_add_mctp_dev(vdm_dev);
+ if (rc) {
+ pr_err("%s: failed to add mctp device\n", __func__);
+ unregister_netdev(ndev);
+ free_netdev(ndev);
+ return ERR_PTR(rc);
+ }
+ return vdm_dev;
+}
+EXPORT_SYMBOL_GPL(mctp_pcie_vdm_add_dev);
+
+void mctp_pcie_vdm_remove_dev(struct mctp_pcie_vdm_dev *vdm_dev)
+{
+ pr_debug("%s: removing vdm_dev %s\n", __func__, vdm_dev->ndev->name);
+ struct net_device *ndev = vdm_dev->ndev;
+
+ if (ndev) {
+ // objects in vdm_dev will be released in net_dev uninit operator
+ mctp_unregister_netdev(ndev);
+ free_netdev(ndev);
+ }
+}
+EXPORT_SYMBOL_GPL(mctp_pcie_vdm_remove_dev);
+
+void mctp_pcie_vdm_notify_rx(struct mctp_pcie_vdm_dev *vdm_dev)
+{
+ queue_work(mctp_pcie_vdm_wq, &vdm_dev->rx_work);
+}
+EXPORT_SYMBOL_GPL(mctp_pcie_vdm_notify_rx);
+
+static __init int mctp_pcie_vdm_mod_init(void)
+{
+ mctp_pcie_vdm_wq = alloc_workqueue("mctp_pcie_vdm_wq", WQ_UNBOUND, 1);
+ if (!mctp_pcie_vdm_wq) {
+ pr_err("Failed to create mctp pcie vdm workqueue\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static __exit void mctp_pcie_vdm_mod_exit(void)
+{
+ struct mctp_pcie_vdm_dev *vdm_dev;
+ struct mctp_pcie_vdm_dev *tmp;
+
+ list_for_each_entry_safe(vdm_dev, tmp, &mctp_pcie_vdm_devs, list) {
+ mctp_pcie_vdm_remove_dev(vdm_dev);
+ }
+}
+
+module_init(mctp_pcie_vdm_mod_init);
+module_exit(mctp_pcie_vdm_mod_exit);
+
+MODULE_DESCRIPTION("MCTP PCIe VDM transport");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("YH <yh_chung@aspeedtech.com>");
diff --git a/include/linux/mctp-pcie-vdm.h b/include/linux/mctp-pcie-vdm.h
new file mode 100644
index 000000000000..da3fad7929b2
--- /dev/null
+++ b/include/linux/mctp-pcie-vdm.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * mctp-pcie-vdm.h - MCTP-over-PCIe-VDM (DMTF DSP0238) transport binding Interface
+ * for PCIe VDM devices to register and implement.
+ *
+ */
+
+#ifndef __LINUX_MCTP_PCIE_VDM_H
+#define __LINUX_MCTP_PCIE_VDM_H
+
+#include <linux/device.h>
+#include <linux/notifier.h>
+
+struct mctp_pcie_vdm_dev;
+
+/**
+ * @send_packet: referenced to send packets with PCIe VDM header packed.
+ * @recv_packet: referenced multiple times until no RX packet to be handled.
+ * received pointer shall start from the PCIe VDM header.
+ * @free_packet: referenced when the packet is processed and okay to be freed.
+ * @uninit: uninitialize the device.
+ */
+struct mctp_pcie_vdm_ops {
+ int (*send_packet)(struct device *dev, u8 *data, size_t len);
+ u8 *(*recv_packet)(struct device *dev);
+ void (*free_packet)(void *packet);
+ void (*uninit)(struct device *dev);
+};
+
+struct mctp_pcie_vdm_dev *mctp_pcie_vdm_add_dev(struct device *dev,
+ const struct mctp_pcie_vdm_ops *ops);
+void mctp_pcie_vdm_remove_dev(struct mctp_pcie_vdm_dev *vdm_dev);
+
+/**
+ * Notify mctp-pcie-vdm that packets are received and ready to be processed.
+ * After notified, mctp-pcie-vdm will call recv_packet() multiple times
+ * until no more packets to be processed. The lower layer driver can keep receiving
+ * packets while the upper layer is processing the received packets.
+ */
+void mctp_pcie_vdm_notify_rx(struct mctp_pcie_vdm_dev *vdm_dev);
+
+#endif /* __LINUX_MCTP_PCIE_VDM_H */
--
2.34.1Hi aspeedyh, kernel test robot noticed the following build warnings: [auto build test WARNING on net-next/main] [also build test WARNING on net/main linus/master v6.16-rc6 next-20250716] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/aspeedyh/net-mctp-Add-MCTP-PCIe-VDM-transport-driver/20250714-142656 base: net-next/main patch link: https://lore.kernel.org/r/20250714062544.2612693-1-yh_chung%40aspeedtech.com patch subject: [PATCH] net: mctp: Add MCTP PCIe VDM transport driver config: powerpc64-randconfig-r122-20250717 (https://download.01.org/0day-ci/archive/20250717/202507171855.3WJVpX2l-lkp@intel.com/config) compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project 16534d19bf50bde879a83f0ae62875e2c5120e64) reproduce: (https://download.01.org/0day-ci/archive/20250717/202507171855.3WJVpX2l-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202507171855.3WJVpX2l-lkp@intel.com/ sparse warnings: (new ones prefixed by >>) >> drivers/net/mctp/mctp-pcie-vdm.c:130:1: sparse: sparse: symbol 'mctp_pcie_vdm_dev_mutex' was not declared. Should it be static? >> drivers/net/mctp/mctp-pcie-vdm.c:131:1: sparse: sparse: symbol 'mctp_pcie_vdm_devs' was not declared. Should it be static? >> drivers/net/mctp/mctp-pcie-vdm.c:132:25: sparse: sparse: symbol 'mctp_pcie_vdm_wq' was not declared. Should it be static? >> drivers/net/mctp/mctp-pcie-vdm.c:343:9: sparse: sparse: incorrect type in assignment (different base types) @@ expected unsigned int [usertype] @@ got restricted __be32 [usertype] @@ drivers/net/mctp/mctp-pcie-vdm.c:343:9: sparse: expected unsigned int [usertype] drivers/net/mctp/mctp-pcie-vdm.c:343:9: sparse: got restricted __be32 [usertype] >> drivers/net/mctp/mctp-pcie-vdm.c:398:17: sparse: sparse: cast to restricted __be32 >> drivers/net/mctp/mctp-pcie-vdm.c:398:17: sparse: sparse: incorrect type in assignment (different base types) @@ expected unsigned int [usertype] @@ got restricted __le32 [usertype] @@ drivers/net/mctp/mctp-pcie-vdm.c:398:17: sparse: expected unsigned int [usertype] drivers/net/mctp/mctp-pcie-vdm.c:398:17: sparse: got restricted __le32 [usertype] drivers/net/mctp/mctp-pcie-vdm.c:453:25: sparse: sparse: cast to restricted __be32 drivers/net/mctp/mctp-pcie-vdm.c:453:25: sparse: sparse: incorrect type in assignment (different base types) @@ expected unsigned int [usertype] @@ got restricted __le32 [usertype] @@ drivers/net/mctp/mctp-pcie-vdm.c:453:25: sparse: expected unsigned int [usertype] drivers/net/mctp/mctp-pcie-vdm.c:453:25: sparse: got restricted __le32 [usertype] vim +/mctp_pcie_vdm_dev_mutex +130 drivers/net/mctp/mctp-pcie-vdm.c 128 129 /* mutex for vdm_devs add/delete */ > 130 DEFINE_MUTEX(mctp_pcie_vdm_dev_mutex); > 131 LIST_HEAD(mctp_pcie_vdm_devs); > 132 struct workqueue_struct *mctp_pcie_vdm_wq; 133 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
Hi aspeedyh,
kernel test robot noticed the following build warnings:
[auto build test WARNING on net-next/main]
[also build test WARNING on net/main linus/master v6.16-rc6 next-20250714]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/aspeedyh/net-mctp-Add-MCTP-PCIe-VDM-transport-driver/20250714-142656
base: net-next/main
patch link: https://lore.kernel.org/r/20250714062544.2612693-1-yh_chung%40aspeedtech.com
patch subject: [PATCH] net: mctp: Add MCTP PCIe VDM transport driver
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20250715/202507151015.GPkeA21H-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250715/202507151015.GPkeA21H-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507151015.GPkeA21H-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> drivers/net/mctp/mctp-pcie-vdm.c:491:4: warning: variable 'vdm_dev' is uninitialized when used here [-Wuninitialized]
491 | vdm_dev->ndev->name);
| ^~~~~~~
include/linux/printk.h:631:26: note: expanded from macro 'pr_debug'
631 | dynamic_pr_debug(fmt, ##__VA_ARGS__)
| ^~~~~~~~~~~
include/linux/dynamic_debug.h:270:22: note: expanded from macro 'dynamic_pr_debug'
270 | pr_fmt(fmt), ##__VA_ARGS__)
| ^~~~~~~~~~~
include/linux/dynamic_debug.h:250:59: note: expanded from macro '_dynamic_func_call'
250 | _dynamic_func_call_cls(_DPRINTK_CLASS_DFLT, fmt, func, ##__VA_ARGS__)
| ^~~~~~~~~~~
include/linux/dynamic_debug.h:248:65: note: expanded from macro '_dynamic_func_call_cls'
248 | __dynamic_func_call_cls(__UNIQUE_ID(ddebug), cls, fmt, func, ##__VA_ARGS__)
| ^~~~~~~~~~~
include/linux/dynamic_debug.h:224:15: note: expanded from macro '__dynamic_func_call_cls'
224 | func(&id, ##__VA_ARGS__); \
| ^~~~~~~~~~~
drivers/net/mctp/mctp-pcie-vdm.c:484:35: note: initialize the variable 'vdm_dev' to silence this warning
484 | struct mctp_pcie_vdm_dev *vdm_dev;
| ^
| = NULL
1 warning generated.
vim +/vdm_dev +491 drivers/net/mctp/mctp-pcie-vdm.c
481
482 static void mctp_pcie_vdm_uninit(struct net_device *ndev)
483 {
484 struct mctp_pcie_vdm_dev *vdm_dev;
485
486 struct mctp_pcie_vdm_route_info *route;
487 struct hlist_node *tmp;
488 int bkt;
489
490 pr_debug("%s: uninitializing vdm_dev %s\n", __func__,
> 491 vdm_dev->ndev->name);
492
493 vdm_dev = netdev_priv(ndev);
494 vdm_dev->callback_ops->uninit(vdm_dev->dev);
495
496 hash_for_each_safe(vdm_dev->route_table, bkt, tmp, route, hnode) {
497 hash_del(&route->hnode);
498 kfree(route);
499 }
500
501 if (vdm_dev->tx_thread) {
502 kthread_stop(vdm_dev->tx_thread);
503 vdm_dev->tx_thread = NULL;
504 }
505
506 if (mctp_pcie_vdm_wq) {
507 cancel_work_sync(&vdm_dev->rx_work);
508 flush_workqueue(mctp_pcie_vdm_wq);
509 destroy_workqueue(mctp_pcie_vdm_wq);
510 mctp_pcie_vdm_wq = NULL;
511 }
512
513 while (__ptr_ring_peek(&vdm_dev->tx_queue)) {
514 struct sk_buff *skb;
515
516 skb = ptr_ring_consume(&vdm_dev->tx_queue);
517
518 if (skb)
519 kfree_skb(skb);
520 }
521
522 mutex_lock(&mctp_pcie_vdm_dev_mutex);
523 list_del(&vdm_dev->list);
524 mutex_unlock(&mctp_pcie_vdm_dev_mutex);
525 }
526
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi YH,
[+CC Khang]
I have some overall questions before we get into a full review of the
series, inline below.
> Add an implementation for DMTF DSP0238 MCTP PCIe VDM transport spec.
>
> Introduce struct mctp_pcie_vdm_dev to represent each PCIe VDM
> interface and its send/receive operations. Register a
> net_device with the MCTP core so packets traverse the standard
> networking socket API.
>
> Because there is no generic PCIe VDM bus framework in-tree, this
> driver provides a transport interface for lower layers to
> implement vendor-specific read/write callbacks.
Do we really need an abstraction for MCTP VDM drivers? How many are you
expecting? Can you point us to a client of the VDM abstraction?
There is some value in keeping consistency for the MCTP lladdr formats
across PCIe transports, but I'm not convinced we need a whole
abstraction layer for this.
> TX path uses a dedicated kernel thread and ptr_ring: skbs queued by the
> MCTP stack are enqueued on the ring and processed in-thread context.
Is this somehow more suitable than the existing netdev queues?
> +struct mctp_pcie_vdm_route_info {
> + u8 eid;
> + u8 dirty;
> + u16 bdf_addr;
> + struct hlist_node hnode;
> +};
Why are you keeping your own routing table in the transport driver? We
already have the route and neighbour tables in the MCTP core code.
Your assumption that you can intercept MCTP control messages to keep a
separate routing table will not work.
> +static void mctp_pcie_vdm_net_setup(struct net_device *ndev)
> +{
> + ndev->type = ARPHRD_MCTP;
> +
> + ndev->mtu = MCTP_PCIE_VDM_MIN_MTU;
> + ndev->min_mtu = MCTP_PCIE_VDM_MIN_MTU;
> + ndev->max_mtu = MCTP_PCIE_VDM_MAX_MTU;
> + ndev->tx_queue_len = MCTP_PCIE_VDM_NET_DEV_TX_QUEUE_LEN;
> + ndev->addr_len = 2; //PCIe bdf is 2 bytes
One of the critical things to get right is the lladdr format for PCIe
VDM devices, as it will be visible to userspace. While the PCIe b/d/fn
data is indeed two bytes, the MCTP addressing format for VDM data is not
entirely representable in two bytes: we also have the routing type to
encode. DSP0238 requires us to use Route to Root Complex and Broadcast
from Root Complex for certain messages, so we need some way to represent
that in your proposed lladdr format.
For this reason, you may want to encode this as [type, bdfn] data.
Also, in flit mode, we also have the segment byte to encode.
Cheers,
Jeremy
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