diff options
Diffstat (limited to 'meta-egvirt')
4 files changed, 1235 insertions, 0 deletions
diff --git a/meta-egvirt/recipes-kernel/kernel-module-virtio-can/files/Kbuild b/meta-egvirt/recipes-kernel/kernel-module-virtio-can/files/Kbuild new file mode 100644 index 00000000..6d9712b8 --- /dev/null +++ b/meta-egvirt/recipes-kernel/kernel-module-virtio-can/files/Kbuild @@ -0,0 +1,7 @@ +# --dirty to mark version with uncommitted changes as dirty +GIT_VERSION = $(shell git -C "$(MODULE_GIT_REPOSITORY_DIR)" describe --tags --dirty | sed 's/^v//') +ccflags-y += -DDRIVER_VERSION=\"$(GIT_VERSION)\" + +ccflags-y += -Werror + +obj-m := virtio_can.o diff --git a/meta-egvirt/recipes-kernel/kernel-module-virtio-can/files/virtio_can.c b/meta-egvirt/recipes-kernel/kernel-module-virtio-can/files/virtio_can.c new file mode 100644 index 00000000..515b3d77 --- /dev/null +++ b/meta-egvirt/recipes-kernel/kernel-module-virtio-can/files/virtio_can.c @@ -0,0 +1,1139 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * CAN bus driver for the Virtio CAN controller + * Copyright (C) 2021 OpenSynergy GmbH + */ + +#include <linux/atomic.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/netdevice.h> +#include <linux/stddef.h> +#include <linux/can/dev.h> +#include <linux/virtio.h> +#include <linux/virtio_ring.h> +#include <linux/version.h> +#include "virtio_can.h" + +#ifndef VIRTIO_ID_CAN +#define VIRTIO_ID_CAN 36 +#endif + +/* CAN device queues */ +#define VIRTIO_CAN_QUEUE_TX 0u /* Driver side view! The device receives here */ +#define VIRTIO_CAN_QUEUE_RX 1u /* Driver side view! The device transmits here */ +#define VIRTIO_CAN_QUEUE_CONTROL 2u +#define VIRTIO_CAN_QUEUE_INDICATION 3u +#define VIRTIO_CAN_QUEUE_COUNT 4u + +#define CAN_KNOWN_FLAGS \ + (VIRTIO_CAN_FLAGS_EXTENDED |\ + VIRTIO_CAN_FLAGS_FD |\ + VIRTIO_CAN_FLAGS_RTR) + +/* napi related */ +#define VIRTIO_CAN_NAPI_WEIGHT NAPI_POLL_WEIGHT + +/* CAN TX message priorities (0 = normal priority) */ +#define VIRTIO_CAN_PRIO_COUNT 1 +/* Max. nummber of in flight TX messages */ +#define VIRTIO_CAN_ECHO_SKB_MAX 128u + +struct virtio_can_tx { + struct list_head list; + int prio; /* Currently always 0 "normal priority" */ + int putidx; + struct virtio_can_tx_out tx_out; + struct virtio_can_tx_in tx_in; +}; + +/* virtio_can private data structure */ +struct virtio_can_priv { + struct can_priv can; /* must be the first member */ + /* NAPI for RX messages */ + struct napi_struct napi; + /* NAPI for TX messages */ + struct napi_struct napi_tx; + /* The network device we're associated with */ + struct net_device *dev; + /* The virtio device we're associated with */ + struct virtio_device *vdev; + /* The virtqueues */ + struct virtqueue *vqs[VIRTIO_CAN_QUEUE_COUNT]; + /* I/O callback function pointers for the virtqueues */ + vq_callback_t *io_callbacks[VIRTIO_CAN_QUEUE_COUNT]; + /* Lock for TX operations */ + spinlock_t tx_lock; + /* Control queue lock. Defensive programming, may be not needed */ + struct mutex ctrl_lock; + /* Wait for control queue processing without polling */ + struct completion ctrl_done; + /* List of virtio CAN TX message */ + struct list_head tx_list; + /* Array of receive queue messages */ + struct virtio_can_rx rpkt[128u]; + /* Those control queue messages cannot live on the stack! */ + struct virtio_can_control_out cpkt_out; + struct virtio_can_control_in cpkt_in; + /* Indication queue message */ + struct virtio_can_event_ind ipkt[1u]; + /* Data to get and maintain the putidx for local TX echo */ + struct list_head tx_putidx_free; + struct list_head *tx_putidx_list; + /* In flight TX messages per prio */ + atomic_t tx_inflight[VIRTIO_CAN_PRIO_COUNT]; + /* Max. In flight TX messages per prio */ + u16 tx_limit[VIRTIO_CAN_PRIO_COUNT]; + /* BusOff pending. Reset after successful indication to upper layer */ + bool busoff_pending; +}; + +/* Function copied from virtio_net.c */ +static void virtqueue_napi_schedule(struct napi_struct *napi, + struct virtqueue *vq) +{ + if (napi_schedule_prep(napi)) { + virtqueue_disable_cb(vq); + __napi_schedule(napi); + } +} + +/* Function copied from virtio_net.c */ +static void virtqueue_napi_complete(struct napi_struct *napi, + struct virtqueue *vq, int processed) +{ + int opaque; + + opaque = virtqueue_enable_cb_prepare(vq); + if (napi_complete_done(napi, processed)) { + if (unlikely(virtqueue_poll(vq, opaque))) + virtqueue_napi_schedule(napi, vq); + } else { + virtqueue_disable_cb(vq); + } +} + +static void virtio_can_free_candev(struct net_device *ndev) +{ + struct virtio_can_priv *priv = netdev_priv(ndev); + + kfree(priv->tx_putidx_list); + free_candev(ndev); +} + +static int virtio_can_alloc_tx_idx(struct virtio_can_priv *priv, int prio) +{ + struct list_head *entry; + + BUG_ON(prio != 0); /* Currently only 1 priority */ + BUG_ON(atomic_read(&priv->tx_inflight[0]) >= priv->can.echo_skb_max); + atomic_add(1, &priv->tx_inflight[prio]); + + if (list_empty(&priv->tx_putidx_free)) + return -1; /* Not expected to happen */ + + entry = priv->tx_putidx_free.next; + list_del(entry); + + return entry - priv->tx_putidx_list; +} + +static void virtio_can_free_tx_idx(struct virtio_can_priv *priv, int prio, + int idx) +{ + BUG_ON(prio >= VIRTIO_CAN_PRIO_COUNT); + BUG_ON(idx >= priv->can.echo_skb_max); + BUG_ON(atomic_read(&priv->tx_inflight[prio]) == 0); + + list_add(&priv->tx_putidx_list[idx], &priv->tx_putidx_free); + atomic_sub(1, &priv->tx_inflight[prio]); +} + +/* Create a scatter-gather list representing our input buffer and put + * it in the queue. + * + * Callers should take appropriate locks. + */ +static int virtio_can_add_inbuf(struct virtqueue *vq, void *buf, + unsigned int size) +{ + struct scatterlist sg[1]; + int ret; + + sg_init_one(sg, buf, size); + + ret = virtqueue_add_inbuf(vq, sg, 1, buf, GFP_ATOMIC); + virtqueue_kick(vq); + if (ret == 0) + ret = vq->num_free; + return ret; +} + +/* Send a control message with message type either + * + * - VIRTIO_CAN_SET_CTRL_MODE_START or + * - VIRTIO_CAN_SET_CTRL_MODE_STOP. + * + * Unlike AUTOSAR CAN Driver Can_SetControllerMode() there is no requirement + * for this Linux driver to have an asynchronous implementation of the mode + * setting function so in order to keep things simple the function is + * implemented as synchronous function. Design pattern is + * virtio_console.c/__send_control_msg() & virtio_net.c/virtnet_send_command(). + */ +static u8 virtio_can_send_ctrl_msg(struct net_device *ndev, u16 msg_type) +{ + struct virtio_can_priv *priv = netdev_priv(ndev); + struct device *dev = &priv->vdev->dev; + struct virtqueue *vq = priv->vqs[VIRTIO_CAN_QUEUE_CONTROL]; + struct scatterlist sg_out[1u]; + struct scatterlist sg_in[1u]; + struct scatterlist *sgs[2u]; + int err; + unsigned int len; + + /* The function may be serialized by rtnl lock. Not sure. + * Better safe than sorry. + */ + mutex_lock(&priv->ctrl_lock); + + priv->cpkt_out.msg_type = cpu_to_le16(msg_type); + sg_init_one(&sg_out[0], &priv->cpkt_out, sizeof(priv->cpkt_out)); + sg_init_one(&sg_in[0], &priv->cpkt_in, sizeof(priv->cpkt_in)); + sgs[0] = sg_out; + sgs[1] = sg_in; + + err = virtqueue_add_sgs(vq, sgs, 1u, 1u, priv, GFP_ATOMIC); + if (err != 0) { + /* Not expected to happen */ + dev_err(dev, "%s(): virtqueue_add_sgs() failed\n", __func__); + } + + if (!virtqueue_kick(vq)) { + /* Not expected to happen */ + dev_err(dev, "%s(): Kick failed\n", __func__); + } + + while (!virtqueue_get_buf(vq, &len) && !virtqueue_is_broken(vq)) + wait_for_completion(&priv->ctrl_done); + + mutex_unlock(&priv->ctrl_lock); + + return priv->cpkt_in.result; +} + +static void virtio_can_start(struct net_device *ndev) +{ + struct virtio_can_priv *priv = netdev_priv(ndev); + u8 result; + + result = virtio_can_send_ctrl_msg(ndev, VIRTIO_CAN_SET_CTRL_MODE_START); + if (result != VIRTIO_CAN_RESULT_OK) { + /* Not expected to happen */ + netdev_err(ndev, "CAN controller start failed\n"); + } + + priv->busoff_pending = false; + priv->can.state = CAN_STATE_ERROR_ACTIVE; + + /* Switch carrier on if device was not connected to the bus */ + if (!netif_carrier_ok(ndev)) + netif_carrier_on(ndev); +} + +/* See also m_can.c/m_can_set_mode() + * + * It is interesting that not only the M-CAN implementation but also all other + * implementations I looked into only support CAN_MODE_START. + * That CAN_MODE_SLEEP is frequently not found to be supported anywhere did not + * come not as surprise but that CAN_MODE_STOP is also never supported was one. + * The function is accessible via the method pointer do_set_mode in + * struct can_priv. As ususal no documentation there. + * May not play any role as grepping through the code did not reveal any place + * from where the method is actually called. + */ +static int virtio_can_set_mode(struct net_device *dev, enum can_mode mode) +{ + switch (mode) { + case CAN_MODE_START: + virtio_can_start(dev); + netif_wake_queue(dev); + break; + default: + return -EOPNOTSUPP; + } + + return 0; +} + +/* Called by issuing "ip link set up can0" */ +static int virtio_can_open(struct net_device *dev) +{ + /* start the virtio_can controller */ + virtio_can_start(dev); + + /* RX and TX napi were already enabled in virtio_can_probe() */ + netif_start_queue(dev); + + return 0; +} + +static void virtio_can_stop(struct net_device *ndev) +{ + struct virtio_can_priv *priv = netdev_priv(ndev); + struct device *dev = &priv->vdev->dev; + u8 result; + + result = virtio_can_send_ctrl_msg(ndev, VIRTIO_CAN_SET_CTRL_MODE_STOP); + if (result != VIRTIO_CAN_RESULT_OK) + dev_err(dev, "CAN controller stop failed\n"); + + priv->busoff_pending = false; + priv->can.state = CAN_STATE_STOPPED; + + /* Switch carrier off if device was connected to the bus */ + if (netif_carrier_ok(ndev)) + netif_carrier_off(ndev); +} + +static int virtio_can_close(struct net_device *dev) +{ + netif_stop_queue(dev); + /* Keep RX napi active to allow dropping of pending RX CAN messages, + * keep TX napi active to allow processing of cancelled CAN messages + */ + virtio_can_stop(dev); + close_candev(dev); + + return 0; +} + +static netdev_tx_t virtio_can_start_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + struct virtio_can_priv *priv = netdev_priv(dev); + struct canfd_frame *cf = (struct canfd_frame *)skb->data; + struct virtio_can_tx *can_tx_msg; + struct virtqueue *vq = priv->vqs[VIRTIO_CAN_QUEUE_TX]; + struct scatterlist sg_out[1u]; + struct scatterlist sg_in[1u]; + struct scatterlist *sgs[2u]; + unsigned long flags; + size_t len; + u32 can_flags; + int err; + int prio = 0; /* Priority is always 0 "normal priority" */ + netdev_tx_t xmit_ret = NETDEV_TX_OK; + const unsigned int hdr_size = offsetof(struct virtio_can_tx_out, sdu); + + if (can_dropped_invalid_skb(dev, skb)) + goto kick; /* No way to return NET_XMIT_DROP here */ + + /* Virtio CAN does not support error message frames */ + if (cf->can_id & CAN_ERR_FLAG) { + kfree_skb(skb); + dev->stats.tx_dropped++; + goto kick; /* No way to return NET_XMIT_DROP here */ + } + + /* No local check for CAN_RTR_FLAG or FD frame against negotiated + * features. The device will reject those anyway if not supported. + */ + + can_tx_msg = kzalloc(sizeof(*can_tx_msg), GFP_ATOMIC); + if (!can_tx_msg) + goto kick; /* No way to return NET_XMIT_DROP here */ + + can_tx_msg->tx_out.msg_type = cpu_to_le16(VIRTIO_CAN_TX); + can_flags = 0u; + if (cf->can_id & CAN_EFF_FLAG) + can_flags |= VIRTIO_CAN_FLAGS_EXTENDED; + if (cf->can_id & CAN_RTR_FLAG) + can_flags |= VIRTIO_CAN_FLAGS_RTR; + if (can_is_canfd_skb(skb)) + can_flags |= VIRTIO_CAN_FLAGS_FD; + can_tx_msg->tx_out.flags = cpu_to_le32(can_flags); + can_tx_msg->tx_out.can_id = cpu_to_le32(cf->can_id & CAN_EFF_MASK); + len = cf->len; + if (len > sizeof(cf->data)) + len = sizeof(cf->data); + if (len > sizeof(can_tx_msg->tx_out.sdu)) + len = sizeof(can_tx_msg->tx_out.sdu); + if (!(can_flags & VIRTIO_CAN_FLAGS_RTR)) { + /* Copy if no RTR frame. RTR frames have a DLC but no payload */ + memcpy(can_tx_msg->tx_out.sdu, cf->data, len); + } + + /* Prepare sending of virtio message */ + sg_init_one(&sg_out[0], &can_tx_msg->tx_out, hdr_size + len); + sg_init_one(&sg_in[0], &can_tx_msg->tx_in, sizeof(can_tx_msg->tx_in)); + sgs[0] = sg_out; + sgs[1] = sg_in; + + /* Find free TX priority */ + if (atomic_read(&priv->tx_inflight[prio]) >= priv->tx_limit[prio]) { + /* May happen if + * - tx_limit[prio] > max # of TX queue messages + */ + netif_stop_queue(dev); + kfree(can_tx_msg); + netdev_dbg(dev, "TX: Stop queue, all prios full\n"); + xmit_ret = NETDEV_TX_BUSY; + goto kick; + } + + /* Normal queue stop when no transmission slots are left */ + if (atomic_read(&priv->tx_inflight[prio]) >= priv->tx_limit[prio]) { + netif_stop_queue(dev); + netdev_dbg(dev, "TX: Normal stop queue\n"); + } + + /* Protect list operations */ + spin_lock_irqsave(&priv->tx_lock, flags); + can_tx_msg->putidx = virtio_can_alloc_tx_idx(priv, prio); + list_add_tail(&can_tx_msg->list, &priv->tx_list); + spin_unlock_irqrestore(&priv->tx_lock, flags); + + BUG_ON(can_tx_msg->putidx < 0); + can_tx_msg->prio = prio; + + /* Push loopback echo. Will be looped back on TX interrupt/TX NAPI */ +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 12, 0) + can_put_echo_skb(skb, dev, can_tx_msg->putidx, 0); +#else + can_put_echo_skb(skb, dev, can_tx_msg->putidx); +#endif + + /* Protect queue and list operations */ + spin_lock_irqsave(&priv->tx_lock, flags); + err = virtqueue_add_sgs(vq, sgs, 1u, 1u, can_tx_msg, GFP_ATOMIC); + if (err != 0) { + list_del(&can_tx_msg->list); + virtio_can_free_tx_idx(priv, can_tx_msg->prio, + can_tx_msg->putidx); + spin_unlock_irqrestore(&priv->tx_lock, flags); + netif_stop_queue(dev); + kfree(can_tx_msg); + if (err == -ENOSPC) + netdev_dbg(dev, "TX: Stop queue, no space left\n"); + else + netdev_warn(dev, "TX: Stop queue, reason = %d\n", err); + xmit_ret = NETDEV_TX_BUSY; + goto kick; + } + spin_unlock_irqrestore(&priv->tx_lock, flags); + +kick: +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 2, 0) + if (netif_queue_stopped(dev) || !netdev_xmit_more()) +#endif + { + if (!virtqueue_kick(vq)) + netdev_err(dev, "%s(): Kick failed\n", __func__); + } + + return xmit_ret; +} + +static const struct net_device_ops virtio_can_netdev_ops = { + .ndo_open = virtio_can_open, + .ndo_stop = virtio_can_close, + .ndo_start_xmit = virtio_can_start_xmit, + .ndo_change_mtu = can_change_mtu, +}; + +static int register_virtio_can_dev(struct net_device *dev) +{ + dev->flags |= IFF_ECHO; /* we support local echo */ + dev->netdev_ops = &virtio_can_netdev_ops; + + return register_candev(dev); +} + +/* Compare with m_can.c/m_can_echo_tx_event() */ +static int virtio_can_read_tx_queue(struct virtqueue *vq) +{ + struct virtio_can_priv *can_priv = vq->vdev->priv; + struct net_device *dev = can_priv->dev; + struct net_device_stats *stats = &dev->stats; + struct virtio_can_tx *can_tx_msg; + unsigned long flags; + unsigned int len; + u8 result; + + /* Protect list and virtio queue operations */ + spin_lock_irqsave(&can_priv->tx_lock, flags); + + can_tx_msg = virtqueue_get_buf(vq, &len); + if (!can_tx_msg) { + spin_unlock_irqrestore(&can_priv->tx_lock, flags); + return 0; /* No more data */ + } + + if (unlikely(len < sizeof(struct virtio_can_tx_in))) { + netdev_err(dev, "TX ACK: Device sent no result code\n"); + result = VIRTIO_CAN_RESULT_NOT_OK; /* Keep things going */ + } else { + result = can_tx_msg->tx_in.result; + } + + if (can_priv->can.state < CAN_STATE_BUS_OFF) { + /* Here also frames with result != VIRTIO_CAN_RESULT_OK are + * echoed. Intentional to bring a waiting process in an upper + * layer to an end. + * TODO: Any better means to indicate a problem here? + */ + if (result != VIRTIO_CAN_RESULT_OK) + netdev_warn(dev, "TX ACK: Result = %u\n", result); + +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 12, 0) + stats->tx_bytes += can_get_echo_skb(dev, can_tx_msg->putidx, NULL); +#else + stats->tx_bytes += can_get_echo_skb(dev, can_tx_msg->putidx); +#endif + stats->tx_packets++; + } else { + netdev_dbg(dev, "TX ACK: Controller inactive, drop echo\n"); +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 13, 0) + can_free_echo_skb(dev, can_tx_msg->putidx, NULL); +#else + can_free_echo_skb(dev, can_tx_msg->putidx); +#endif + } + + list_del(&can_tx_msg->list); + virtio_can_free_tx_idx(can_priv, can_tx_msg->prio, can_tx_msg->putidx); + + spin_unlock_irqrestore(&can_priv->tx_lock, flags); + + kfree(can_tx_msg); + + /* Flow control */ + if (netif_queue_stopped(dev)) { + netdev_dbg(dev, "TX ACK: Wake up stopped queue\n"); + netif_wake_queue(dev); + } + + return 1; /* Queue was not emtpy so there may be more data */ +} + +/* Poll TX used queue for sent CAN messages + * See https://wiki.linuxfoundation.org/networking/napi function + * int (*poll)(struct napi_struct *napi, int budget); + */ +static int virtio_can_tx_poll(struct napi_struct *napi, int quota) +{ + struct net_device *dev = napi->dev; + struct virtio_can_priv *priv = netdev_priv(dev); + struct virtqueue *vq = priv->vqs[VIRTIO_CAN_QUEUE_TX]; + int work_done = 0; + + while (work_done < quota && virtio_can_read_tx_queue(vq) != 0) + work_done++; + + if (work_done < quota) + virtqueue_napi_complete(napi, vq, work_done); + + return work_done; +} + +static void virtio_can_tx_intr(struct virtqueue *vq) +{ + struct virtio_can_priv *can_priv = vq->vdev->priv; + + virtqueue_disable_cb(vq); + napi_schedule(&can_priv->napi_tx); +} + +/* This function is the NAPI RX poll function and NAPI guarantees that this + * function is not invoked simulataneously on multiply processors. + * Read a RX message from the used queue and sends it to the upper layer. + * (See also m_can.c / m_can_read_fifo()). + */ +static int virtio_can_read_rx_queue(struct virtqueue *vq) +{ + struct virtio_can_priv *priv = vq->vdev->priv; + struct net_device *dev = priv->dev; + struct net_device_stats *stats = &dev->stats; + struct virtio_can_rx *can_rx; + struct canfd_frame *cf; + struct sk_buff *skb; + unsigned int len; + const unsigned int header_size = offsetof(struct virtio_can_rx, sdu); + u16 msg_type; + u32 can_flags; + u32 can_id; + + can_rx = virtqueue_get_buf(vq, &len); + if (!can_rx) + return 0; /* No more data */ + + if (len < header_size) { + netdev_warn(dev, "RX: Message too small\n"); + goto putback; + } + + if (priv->can.state >= CAN_STATE_ERROR_PASSIVE) { + netdev_dbg(dev, "%s(): Controller not active\n", __func__); + goto putback; + } + + msg_type = le16_to_cpu(can_rx->msg_type); + if (msg_type != VIRTIO_CAN_RX) { + netdev_warn(dev, "RX: Got unknown msg_type %04x\n", msg_type); + goto putback; + } + + len -= header_size; /* Payload only now */ + can_flags = le32_to_cpu(can_rx->flags); + can_id = le32_to_cpu(can_rx->can_id); + + if (can_flags & ~CAN_KNOWN_FLAGS) { + stats->rx_dropped++; + netdev_warn(dev, "RX: CAN Id 0x%08x: Invalid flags 0x%x\n", + can_id, can_flags); + goto putback; + } + + if (can_flags & VIRTIO_CAN_FLAGS_EXTENDED) { + can_id &= CAN_EFF_MASK; + can_id |= CAN_EFF_FLAG; + } else { + can_id &= CAN_SFF_MASK; + } + + if (can_flags & VIRTIO_CAN_FLAGS_RTR) { + if (!virtio_has_feature(vq->vdev, VIRTIO_CAN_F_RTR_FRAMES)) { + stats->rx_dropped++; + netdev_warn(dev, "RX: CAN Id 0x%08x: RTR not negotiated\n", + can_id); + goto putback; + } + if (can_flags & VIRTIO_CAN_FLAGS_FD) { + stats->rx_dropped++; + netdev_warn(dev, "RX: CAN Id 0x%08x: RTR with FD not possible\n", + can_id); + goto putback; + } + + /* For RTR frames we have determined a len value here from a + * payload length while RTR frames have no payload. Could be + * reason enough to add a dlc field to virtio CAN RX and virtio + * CAN TX messages avoiding to have a dummy payload here. + */ + if (len > 0xF) { + stats->rx_dropped++; + netdev_warn(dev, "RX: CAN Id 0x%08x: RTR with len != 0\n", + can_id); + goto putback; + } + + if (len > 0x8) + len = 0x8; + + can_id |= CAN_RTR_FLAG; + } + + if (can_flags & VIRTIO_CAN_FLAGS_FD) { + if (!virtio_has_feature(vq->vdev, VIRTIO_CAN_F_CAN_FD)) { + stats->rx_dropped++; + netdev_warn(dev, "RX: CAN Id 0x%08x: FD not negotiated\n", + can_id); + goto putback; + } + + if (len > CANFD_MAX_DLEN) + len = CANFD_MAX_DLEN; + + skb = alloc_canfd_skb(priv->dev, &cf); + } else { + if (!virtio_has_feature(vq->vdev, VIRTIO_CAN_F_CAN_CLASSIC)) { + stats->rx_dropped++; + netdev_warn(dev, "RX: CAN Id 0x%08x: classic not negotiated\n", + can_id); + goto putback; + } + + if (len > CAN_MAX_DLEN) + len = CAN_MAX_DLEN; + + skb = alloc_can_skb(priv->dev, (struct can_frame **)&cf); + } + if (!skb) { + stats->rx_dropped++; + netdev_warn(dev, "RX: No skb available\n"); + goto putback; + } + + cf->can_id = can_id; + cf->len = len; + if (!(can_flags & VIRTIO_CAN_FLAGS_RTR)) { + /* RTR frames have a DLC but no payload */ + memcpy(cf->data, can_rx->sdu, len); + } + + if (netif_receive_skb(skb) == NET_RX_SUCCESS) { + stats->rx_packets++; + if (!(can_flags & VIRTIO_CAN_FLAGS_RTR)) + stats->rx_bytes += cf->len; + } + +putback: + /* Put processed RX buffer back into avail queue */ + virtio_can_add_inbuf(vq, can_rx, sizeof(struct virtio_can_rx)); + + return 1; /* Queue was not emtpy so there may be more data */ +} + +/* See m_can_poll() / m_can_handle_state_errors() m_can_handle_state_change() */ +static int virtio_can_handle_busoff(struct net_device *dev) +{ + struct virtio_can_priv *priv = netdev_priv(dev); + struct net_device_stats *stats = &dev->stats; + struct can_frame *cf; + struct sk_buff *skb; + u8 rx_bytes; + + if (!priv->busoff_pending) + return 0; + + if (priv->can.state < CAN_STATE_BUS_OFF) { + netdev_dbg(dev, "entered error bus off state\n"); + + /* bus-off state */ + priv->can.state = CAN_STATE_BUS_OFF; + priv->can.can_stats.bus_off++; + can_bus_off(dev); + } + + /* propagate the error condition to the CAN stack */ + skb = alloc_can_err_skb(dev, &cf); + if (unlikely(!skb)) + return 0; + + /* bus-off state */ + cf->can_id |= CAN_ERR_BUSOFF; + rx_bytes = cf->can_dlc; + + /* Ensure that the BusOff indication does not get lost */ + if (netif_receive_skb(skb) == NET_RX_SUCCESS) + priv->busoff_pending = false; + + stats->rx_packets++; + stats->rx_bytes += rx_bytes; + + return 1; +} + +/* Poll RX used queue for received CAN messages + * See https://wiki.linuxfoundation.org/networking/napi function + * int (*poll)(struct napi_struct *napi, int budget); + * Important: "The networking subsystem promises that poll() will not be + * invoked simultaneously (for the same napi_struct) on multiple processors" + */ +static int virtio_can_rx_poll(struct napi_struct *napi, int quota) +{ + struct net_device *dev = napi->dev; + struct virtio_can_priv *priv = netdev_priv(dev); + struct virtqueue *vq = priv->vqs[VIRTIO_CAN_QUEUE_RX]; + int work_done = 0; + + work_done += virtio_can_handle_busoff(dev); + + while (work_done < quota && virtio_can_read_rx_queue(vq) != 0) + work_done++; + + if (work_done < quota) + virtqueue_napi_complete(napi, vq, work_done); + + return work_done; +} + +static void virtio_can_rx_intr(struct virtqueue *vq) +{ + struct virtio_can_priv *can_priv = vq->vdev->priv; + + virtqueue_disable_cb(vq); + napi_schedule(&can_priv->napi); +} + +static void virtio_can_control_intr(struct virtqueue *vq) +{ + struct virtio_can_priv *can_priv = vq->vdev->priv; + + complete(&can_priv->ctrl_done); +} + +static void virtio_can_evind_intr(struct virtqueue *vq) +{ + struct virtio_can_priv *can_priv = vq->vdev->priv; + struct net_device *dev = can_priv->dev; + struct virtio_can_event_ind *evind; + unsigned int len; + u16 msg_type; + + for (;;) { + /* The interrupt function is not assumed to be interrupted by + * itself so locks should not be needed for queue operations. + */ + evind = virtqueue_get_buf(vq, &len); + if (!evind) + return; /* No more messages */ + + if (len < sizeof(struct virtio_can_event_ind)) { + netdev_warn(dev, "Evind: Message too small\n"); + goto putback; + } + + msg_type = le16_to_cpu(evind->msg_type); + if (msg_type != VIRTIO_CAN_BUSOFF_IND) { + netdev_warn(dev, "Evind: Got unknown msg_type %04x\n", + msg_type); + goto putback; + } + + if (!can_priv->busoff_pending && + can_priv->can.state < CAN_STATE_BUS_OFF) { + can_priv->busoff_pending = true; + napi_schedule(&can_priv->napi); + } + +putback: + /* Put processed event ind buffer back into avail queue */ + virtio_can_add_inbuf(vq, evind, + sizeof(struct virtio_can_event_ind)); + } +} + +static void virtio_can_populate_vqs(struct virtio_device *vdev) + +{ + struct virtio_can_priv *priv = vdev->priv; + struct virtqueue *vq; + unsigned int idx; + int ret; + + // TODO: Think again a moment if here locks already may be needed! + + /* Fill RX queue */ + vq = priv->vqs[VIRTIO_CAN_QUEUE_RX]; + for (idx = 0u; idx < ARRAY_SIZE(priv->rpkt); idx++) { + ret = virtio_can_add_inbuf(vq, &priv->rpkt[idx], + sizeof(struct virtio_can_rx)); + if (ret < 0) { + dev_dbg(&vdev->dev, "rpkt fill: ret=%d, idx=%u\n", + ret, idx); + break; + } + } + dev_dbg(&vdev->dev, "%u rpkt added\n", idx); + + /* Fill event indication queue */ + vq = priv->vqs[VIRTIO_CAN_QUEUE_INDICATION]; + for (idx = 0u; idx < ARRAY_SIZE(priv->ipkt); idx++) { + ret = virtio_can_add_inbuf(vq, &priv->ipkt[idx], + sizeof(struct virtio_can_event_ind)); + if (ret < 0) { + dev_dbg(&vdev->dev, "ipkt fill: ret=%d, idx=%u\n", + ret, idx); + break; + } + } + dev_dbg(&vdev->dev, "%u ipkt added\n", idx); +} + +static int virtio_can_find_vqs(struct virtio_can_priv *priv) +{ + /* The order of RX and TX is exactly the opposite as in console and + * network. Does not play any role but is a bad trap. + */ + static const char * const io_names[VIRTIO_CAN_QUEUE_COUNT] = { + "can-tx", + "can-rx", + "can-state-ctrl", + "can-event-ind" + }; + + priv->io_callbacks[VIRTIO_CAN_QUEUE_TX] = virtio_can_tx_intr; + priv->io_callbacks[VIRTIO_CAN_QUEUE_RX] = virtio_can_rx_intr; + priv->io_callbacks[VIRTIO_CAN_QUEUE_CONTROL] = virtio_can_control_intr; + priv->io_callbacks[VIRTIO_CAN_QUEUE_INDICATION] = virtio_can_evind_intr; + + /* Find the queues. */ + return virtio_find_vqs(priv->vdev, VIRTIO_CAN_QUEUE_COUNT, priv->vqs, + priv->io_callbacks, io_names, NULL); +} + +/* Function must not be called before virtio_can_find_vqs() has been run */ +static void virtio_can_del_vq(struct virtio_device *vdev) +{ + struct virtio_can_priv *priv = vdev->priv; + struct list_head *cursor, *next; + struct virtqueue *vq; + + /* Reset the device */ + if (vdev->config->reset) + vdev->config->reset(vdev); + + /* From here we have dead silence from the device side so no locks + * are needed to protect against device side events. + */ + + vq = priv->vqs[VIRTIO_CAN_QUEUE_INDICATION]; + while (virtqueue_detach_unused_buf(vq)) + ; /* Do nothing, content allocated statically */ + + vq = priv->vqs[VIRTIO_CAN_QUEUE_CONTROL]; + while (virtqueue_detach_unused_buf(vq)) + ; /* Do nothing, content allocated statically */ + + vq = priv->vqs[VIRTIO_CAN_QUEUE_RX]; + while (virtqueue_detach_unused_buf(vq)) + ; /* Do nothing, content allocated statically */ + + vq = priv->vqs[VIRTIO_CAN_QUEUE_TX]; + while (virtqueue_detach_unused_buf(vq)) + ; /* Do nothing, content to be de-allocated separately */ + + /* Is keeping track of allocated elements by an own linked list + * really necessary or may this be optimized using only + * virtqueue_detach_unused_buf()? + */ + list_for_each_safe(cursor, next, &priv->tx_list) { + struct virtio_can_tx *can_tx; + + can_tx = list_entry(cursor, struct virtio_can_tx, list); + list_del(cursor); + kfree(can_tx); + } + + if (vdev->config->del_vqs) + vdev->config->del_vqs(vdev); +} + +/* See virtio_net.c/virtnet_remove() and also m_can.c/m_can_plat_remove() */ +static void virtio_can_remove(struct virtio_device *vdev) +{ + struct virtio_can_priv *priv = vdev->priv; + struct net_device *dev = priv->dev; + + unregister_candev(dev); + + /* No calls of netif_napi_del() needed as free_candev() will do this */ + + virtio_can_del_vq(vdev); + + virtio_can_free_candev(dev); +} + +static int virtio_can_validate(struct virtio_device *vdev) +{ + /* CAN needs always access to the config space. + * Check that the driver can access the config space + */ + if (!vdev->config->get) { + dev_err(&vdev->dev, "%s failure: config access disabled\n", + __func__); + return -EINVAL; + } + + if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) { + dev_err(&vdev->dev, + "device does not comply with spec version 1.x\n"); + return -EINVAL; + } + + return 0; +} + +static int virtio_can_probe(struct virtio_device *vdev) +{ + struct net_device *dev; + struct virtio_can_priv *priv; + int err; + unsigned int echo_skb_max; + unsigned int idx; + u16 lo_tx = VIRTIO_CAN_ECHO_SKB_MAX; + + echo_skb_max = lo_tx; + dev = alloc_candev(sizeof(struct virtio_can_priv), echo_skb_max); + if (!dev) + return -ENOMEM; + + priv = netdev_priv(dev); + + priv->tx_putidx_list = + kcalloc(echo_skb_max, sizeof(struct list_head), GFP_KERNEL); + if (!priv->tx_putidx_list) { + free_candev(dev); + return -ENOMEM; + } + + INIT_LIST_HEAD(&priv->tx_putidx_free); + for (idx = 0u; idx < echo_skb_max; idx++) + list_add_tail(&priv->tx_putidx_list[idx], + &priv->tx_putidx_free); + + netif_napi_add(dev, &priv->napi, virtio_can_rx_poll, + VIRTIO_CAN_NAPI_WEIGHT); + netif_napi_add(dev, &priv->napi_tx, virtio_can_tx_poll, + VIRTIO_CAN_NAPI_WEIGHT); + + SET_NETDEV_DEV(dev, &vdev->dev); + + priv->dev = dev; + priv->vdev = vdev; + vdev->priv = priv; + + priv->can.do_set_mode = virtio_can_set_mode; + priv->can.state = CAN_STATE_STOPPED; + /* Set Virtio CAN supported operations */ + priv->can.ctrlmode_supported = CAN_CTRLMODE_BERR_REPORTING; + if (virtio_has_feature(vdev, VIRTIO_CAN_F_CAN_FD)) { +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 17, 0) + err = can_set_static_ctrlmode(dev, CAN_CTRLMODE_FD); + if (err != 0) + goto on_failure; +#else + can_set_static_ctrlmode(dev, CAN_CTRLMODE_FD); +#endif + } + + /* Initialize virtqueues */ + err = virtio_can_find_vqs(priv); + if (err != 0) + goto on_failure; + + /* It is possible to consider the number of TX queue places to + * introduce a stricter TX flow control. Question is if this should + * be done permanently this way in the Linux virtio CAN driver. + */ + if (true) { + struct virtqueue *vq = priv->vqs[VIRTIO_CAN_QUEUE_TX]; + unsigned int tx_slots = vq->num_free; + + if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) + tx_slots >>= 1; + if (lo_tx > tx_slots) + lo_tx = tx_slots; + } + + priv->tx_limit[0] = lo_tx; + + INIT_LIST_HEAD(&priv->tx_list); + + spin_lock_init(&priv->tx_lock); + mutex_init(&priv->ctrl_lock); + + init_completion(&priv->ctrl_done); + + virtio_can_populate_vqs(vdev); + + register_virtio_can_dev(dev); + + napi_enable(&priv->napi); + napi_enable(&priv->napi_tx); + + /* Request device going live */ + virtio_device_ready(vdev); /* Optionally done by virtio_dev_probe() */ + + return 0; + +on_failure: + virtio_can_free_candev(dev); + return err; +} + +#ifdef CONFIG_PM_SLEEP +/* Compare with m_can.c/m_can_suspend(), virtio_net.c/virtnet_freeze() and + * virtio_card.c/virtsnd_freeze() + */ +static int virtio_can_freeze(struct virtio_device *vdev) +{ + struct virtio_can_priv *priv = vdev->priv; + struct net_device *ndev = priv->dev; + + napi_disable(&priv->napi); + napi_disable(&priv->napi_tx); + + if (netif_running(ndev)) { + netif_stop_queue(ndev); + netif_device_detach(ndev); + virtio_can_stop(ndev); + } + + priv->can.state = CAN_STATE_SLEEPING; + + virtio_can_del_vq(vdev); + + return 0; +} + +/* Compare with m_can.c/m_can_resume(), virtio_net.c/virtnet_restore() and + * virtio_card.c/virtsnd_restore() + */ +static int virtio_can_restore(struct virtio_device *vdev) +{ + struct virtio_can_priv *priv = vdev->priv; + struct net_device *ndev = priv->dev; + int err; + + err = virtio_can_find_vqs(priv); + if (err != 0) + return err; + virtio_can_populate_vqs(vdev); + + priv->can.state = CAN_STATE_ERROR_ACTIVE; + + if (netif_running(ndev)) { + virtio_can_start(ndev); + netif_device_attach(ndev); + netif_start_queue(ndev); + } + + napi_enable(&priv->napi); + napi_enable(&priv->napi_tx); + + return 0; +} +#endif /* #ifdef CONFIG_PM_SLEEP */ + +static struct virtio_device_id virtio_can_id_table[] = { + { VIRTIO_ID_CAN, VIRTIO_DEV_ANY_ID }, + { 0 }, +}; + +static unsigned int features[] = { + VIRTIO_CAN_F_CAN_CLASSIC, + VIRTIO_CAN_F_CAN_FD, + VIRTIO_CAN_F_LATE_TX_ACK, + VIRTIO_CAN_F_RTR_FRAMES, +}; + +static struct virtio_driver virtio_can_driver = { + .feature_table = features, + .feature_table_size = ARRAY_SIZE(features), + .feature_table_legacy = NULL, + .feature_table_size_legacy = 0u, + .driver.name = KBUILD_MODNAME, + .driver.owner = THIS_MODULE, + .id_table = virtio_can_id_table, + .validate = virtio_can_validate, + .probe = virtio_can_probe, + .remove = virtio_can_remove, + .config_changed = NULL, +#ifdef CONFIG_PM_SLEEP + .freeze = virtio_can_freeze, + .restore = virtio_can_restore, +#endif +}; + +module_virtio_driver(virtio_can_driver); +MODULE_DEVICE_TABLE(virtio, virtio_can_id_table); + +MODULE_AUTHOR("OpenSynergy GmbH"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("CAN bus driver for Virtio CAN controller"); +MODULE_VERSION(DRIVER_VERSION); diff --git a/meta-egvirt/recipes-kernel/kernel-module-virtio-can/files/virtio_can.h b/meta-egvirt/recipes-kernel/kernel-module-virtio-can/files/virtio_can.h new file mode 100644 index 00000000..0ca75c7a --- /dev/null +++ b/meta-egvirt/recipes-kernel/kernel-module-virtio-can/files/virtio_can.h @@ -0,0 +1,69 @@ +/* SPDX-License-Identifier: BSD-3-Clause */ +/* + * Copyright (C) 2021 OpenSynergy GmbH + */ +#ifndef _LINUX_VIRTIO_VIRTIO_CAN_H +#define _LINUX_VIRTIO_VIRTIO_CAN_H + +#include <linux/types.h> +#include <linux/virtio_types.h> +#include <linux/virtio_ids.h> +#include <linux/virtio_config.h> + +/* Feature bit numbers */ +#define VIRTIO_CAN_F_CAN_CLASSIC 0u +#define VIRTIO_CAN_F_CAN_FD 1u +#define VIRTIO_CAN_F_LATE_TX_ACK 2u +#define VIRTIO_CAN_F_RTR_FRAMES 3u + +/* CAN Result Types */ +#define VIRTIO_CAN_RESULT_OK 0u +#define VIRTIO_CAN_RESULT_NOT_OK 1u + +/* CAN flags to determine type of CAN Id */ +#define VIRTIO_CAN_FLAGS_EXTENDED 0x8000u +#define VIRTIO_CAN_FLAGS_FD 0x4000u +#define VIRTIO_CAN_FLAGS_RTR 0x2000u + +/* TX queue message types */ +struct virtio_can_tx_out { +#define VIRTIO_CAN_TX 0x0001u + __le16 msg_type; + __le16 reserved; + __le32 flags; + __le32 can_id; + __u8 sdu[64u]; +}; + +struct virtio_can_tx_in { + __u8 result; +}; + +/* RX queue message types */ +struct virtio_can_rx { +#define VIRTIO_CAN_RX 0x0101u + __le16 msg_type; + __le16 reserved; + __le32 flags; + __le32 can_id; + __u8 sdu[64u]; +}; + +/* Control queue message types */ +struct virtio_can_control_out { +#define VIRTIO_CAN_SET_CTRL_MODE_START 0x0201u +#define VIRTIO_CAN_SET_CTRL_MODE_STOP 0x0202u + __le16 msg_type; +}; + +struct virtio_can_control_in { + __u8 result; +}; + +/* Indication queue message types */ +struct virtio_can_event_ind { +#define VIRTIO_CAN_BUSOFF_IND 0x0301u + __le16 msg_type; +}; + +#endif /* #ifndef _LINUX_VIRTIO_VIRTIO_CAN_H */ diff --git a/meta-egvirt/recipes-kernel/kernel-module-virtio-can/kernel-module-virtio-can.bb b/meta-egvirt/recipes-kernel/kernel-module-virtio-can/kernel-module-virtio-can.bb new file mode 100644 index 00000000..e8327de4 --- /dev/null +++ b/meta-egvirt/recipes-kernel/kernel-module-virtio-can/kernel-module-virtio-can.bb @@ -0,0 +1,20 @@ +SUMMARY = "VIRTIO CAN device driver" + +LICENSE = "BSD-3-Clause & GPL-2.0-only" +LIC_FILES_CHKSUM = " \ + file://virtio_can.h;endline=4;md5=d93ffb4ab090b382cbcda4cb2c0e5c9c \ + file://virtio_can.c;endline=5;md5=06e45bdf8cb26f6a72e240cb1b0c18c2 \ +" + +inherit module + +SRC_URI = " \ + file://Kbuild \ + file://virtio_can.c \ + file://virtio_can.h \ +" + +S = "${WORKDIR}" + +MAKE_TARGETS = "-C ${STAGING_KERNEL_DIR} M=${WORKDIR} MODULE_GIT_REPOSITORY_DIR=${METADIR}/meta-agl-devel" +MODULES_INSTALL_TARGET = "-C ${STAGING_KERNEL_DIR} M=${WORKDIR} modules_install" |