| Message ID | 1603902898-25233-2-git-send-email-loic.poulain@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | None | expand |
Hi Loic, On Wed, Oct 28, 2020 at 05:34:58PM +0100, Loic Poulain wrote: > This patch adds a new network driver implementing MHI transport for > network packets. Packets can be in any format, though QMAP (rmnet) > is the usual protocol (flow control + PDN mux). > > It support two MHI devices, IP_HW0 which is, the path to the IPA > (IP accelerator) on qcom modem, And IP_SW0 which is the software > driven IP path (to modem CPU). > This patch looks good to me. I just commented few nits inline. With those addressed, you can have my: Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Thanks, Mani > Signed-off-by: Loic Poulain <loic.poulain@linaro.org> > --- > v2: - rebase on net-next > - remove useless skb_linearize > - check error type on mhi_queue return > - rate limited errors > - Schedule RX refill only on 'low' buf level > - SET_NETDEV_DEV in probe > - reorder device remove sequence > v3: - Stop channels on net_register error > - Remove useles parentheses > - Add driver .owner > v4: - prevent potential cpu hog in rx-refill loop > - Access mtu via READ_ONCE > v5: - Fix access to u64 stats > v6: - Stop TX queue earlier if queue is full > - Preventing 'abnormal' NETDEV_TX_BUSY path > v7: - Stop dl/ul cb operations on channel resetting > v8: - remove premature comment about TX threading gain > - check rx_queued to determine queuing limits > - fix probe error path (unified goto usage) > > drivers/net/Kconfig | 7 ++ > drivers/net/Makefile | 1 + > drivers/net/mhi_net.c | 313 ++++++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 321 insertions(+) > create mode 100644 drivers/net/mhi_net.c > > diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig > index 1368d1d..11a6357 100644 > --- a/drivers/net/Kconfig > +++ b/drivers/net/Kconfig > @@ -426,6 +426,13 @@ config VSOCKMON > mostly intended for developers or support to debug vsock issues. If > unsure, say N. > > +config MHI_NET > + tristate "MHI network driver" > + depends on MHI_BUS > + help > + This is the network driver for MHI. It can be used with network driver for MHI bus. > + QCOM based WWAN modems (like SDX55). Say Y or M. > + > endif # NET_CORE > > config SUNGEM_PHY > diff --git a/drivers/net/Makefile b/drivers/net/Makefile > index 94b6080..8312037 100644 > --- a/drivers/net/Makefile > +++ b/drivers/net/Makefile > @@ -34,6 +34,7 @@ obj-$(CONFIG_GTP) += gtp.o > obj-$(CONFIG_NLMON) += nlmon.o > obj-$(CONFIG_NET_VRF) += vrf.o > obj-$(CONFIG_VSOCKMON) += vsockmon.o > +obj-$(CONFIG_MHI_NET) += mhi_net.o > > # > # Networking Drivers > diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c > new file mode 100644 > index 0000000..4ba146d > --- /dev/null > +++ b/drivers/net/mhi_net.c > @@ -0,0 +1,313 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* MHI Network driver - Network over MHI Network over MHI bus. > + * > + * Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org> > + */ > + > +#include <linux/if_arp.h> > +#include <linux/mhi.h> > +#include <linux/mod_devicetable.h> > +#include <linux/module.h> > +#include <linux/netdevice.h> > +#include <linux/skbuff.h> > +#include <linux/u64_stats_sync.h> > + > +#define MIN_MTU ETH_MIN_MTU > +#define MAX_MTU 0xffff > +#define DEFAULT_MTU 16384 Please add a prefix to avoid namespace issues in future... > + > +struct mhi_net_stats { > + u64_stats_t rx_packets; > + u64_stats_t rx_bytes; > + u64_stats_t rx_errors; > + u64_stats_t rx_dropped; > + u64_stats_t tx_packets; > + u64_stats_t tx_bytes; > + u64_stats_t tx_errors; > + u64_stats_t tx_dropped; > + atomic_t rx_queued; > + struct u64_stats_sync tx_syncp; > + struct u64_stats_sync rx_syncp; > +}; > + > +struct mhi_net_dev { > + struct mhi_device *mdev; > + struct net_device *ndev; > + struct delayed_work rx_refill; > + struct mhi_net_stats stats; > + u32 rx_queue_sz; > +}; > + [...] > +static void mhi_net_rx_refill_work(struct work_struct *work) > +{ > + struct mhi_net_dev *mhi_netdev = container_of(work, struct mhi_net_dev, > + rx_refill.work); > + struct net_device *ndev = mhi_netdev->ndev; > + struct mhi_device *mdev = mhi_netdev->mdev; > + int size = READ_ONCE(ndev->mtu); > + struct sk_buff *skb; > + int err; > + > + do { > + skb = netdev_alloc_skb(ndev, size); > + if (unlikely(!skb)) > + break; > + > + err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb, size, MHI_EOT); > + if (unlikely(err)) { > + net_err_ratelimited("%s: Failed to queue RX buf (%d)\n", > + ndev->name, err); > + kfree_skb(skb); > + break; > + } > + > + /* Do not hog the CPU if rx buffers are completed faster than > + * queued (unlikely). s/completed/consumed > + */ > + cond_resched(); > + } while (atomic_inc_return(&mhi_netdev->stats.rx_queued) < mhi_netdev->rx_queue_sz); > + > + /* If we're still starved of rx buffers, reschedule later */ > + if (unlikely(!atomic_read(&mhi_netdev->stats.rx_queued))) > + schedule_delayed_work(&mhi_netdev->rx_refill, HZ / 2); > +} > + > +static int mhi_net_probe(struct mhi_device *mhi_dev, > + const struct mhi_device_id *id) > +{ > + const char *netname = (char *)id->driver_data; > + struct mhi_net_dev *mhi_netdev; > + struct net_device *ndev; > + struct device *dev = &mhi_dev->dev; > + int err; Since this is a networking driver, please stick to reverse xmas tree order for local variables.
On Fri, 30 Oct 2020 at 09:14, Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> wrote: > > Hi Loic, > > On Wed, Oct 28, 2020 at 05:34:58PM +0100, Loic Poulain wrote: > > This patch adds a new network driver implementing MHI transport for > > network packets. Packets can be in any format, though QMAP (rmnet) > > is the usual protocol (flow control + PDN mux). > > > > It support two MHI devices, IP_HW0 which is, the path to the IPA > > (IP accelerator) on qcom modem, And IP_SW0 which is the software > > driven IP path (to modem CPU). > > > > This patch looks good to me. I just commented few nits inline. With those > addressed, you can have my: > > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Thanks for your review Mani, going to address that points in v9. > > Thanks, > Mani > > > Signed-off-by: Loic Poulain <loic.poulain@linaro.org> > > --- > > v2: - rebase on net-next > > - remove useless skb_linearize > > - check error type on mhi_queue return > > - rate limited errors > > - Schedule RX refill only on 'low' buf level > > - SET_NETDEV_DEV in probe > > - reorder device remove sequence > > v3: - Stop channels on net_register error > > - Remove useles parentheses > > - Add driver .owner > > v4: - prevent potential cpu hog in rx-refill loop > > - Access mtu via READ_ONCE > > v5: - Fix access to u64 stats > > v6: - Stop TX queue earlier if queue is full > > - Preventing 'abnormal' NETDEV_TX_BUSY path > > v7: - Stop dl/ul cb operations on channel resetting > > v8: - remove premature comment about TX threading gain > > - check rx_queued to determine queuing limits > > - fix probe error path (unified goto usage) > > > > drivers/net/Kconfig | 7 ++ > > drivers/net/Makefile | 1 + > > drivers/net/mhi_net.c | 313 ++++++++++++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 321 insertions(+) > > create mode 100644 drivers/net/mhi_net.c > > > > diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig > > index 1368d1d..11a6357 100644 > > --- a/drivers/net/Kconfig > > +++ b/drivers/net/Kconfig > > @@ -426,6 +426,13 @@ config VSOCKMON > > mostly intended for developers or support to debug vsock issues. If > > unsure, say N. > > > > +config MHI_NET > > + tristate "MHI network driver" > > + depends on MHI_BUS > > + help > > + This is the network driver for MHI. It can be used with > > network driver for MHI bus. > > > + QCOM based WWAN modems (like SDX55). Say Y or M. > > + > > endif # NET_CORE > > > > config SUNGEM_PHY > > diff --git a/drivers/net/Makefile b/drivers/net/Makefile > > index 94b6080..8312037 100644 > > --- a/drivers/net/Makefile > > +++ b/drivers/net/Makefile > > @@ -34,6 +34,7 @@ obj-$(CONFIG_GTP) += gtp.o > > obj-$(CONFIG_NLMON) += nlmon.o > > obj-$(CONFIG_NET_VRF) += vrf.o > > obj-$(CONFIG_VSOCKMON) += vsockmon.o > > +obj-$(CONFIG_MHI_NET) += mhi_net.o > > > > # > > # Networking Drivers > > diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c > > new file mode 100644 > > index 0000000..4ba146d > > --- /dev/null > > +++ b/drivers/net/mhi_net.c > > @@ -0,0 +1,313 @@ > > +// SPDX-License-Identifier: GPL-2.0-or-later > > +/* MHI Network driver - Network over MHI > > Network over MHI bus. > > > + * > > + * Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org> > > + */ > > + > > +#include <linux/if_arp.h> > > +#include <linux/mhi.h> > > +#include <linux/mod_devicetable.h> > > +#include <linux/module.h> > > +#include <linux/netdevice.h> > > +#include <linux/skbuff.h> > > +#include <linux/u64_stats_sync.h> > > + > > +#define MIN_MTU ETH_MIN_MTU > > +#define MAX_MTU 0xffff > > +#define DEFAULT_MTU 16384 > > Please add a prefix to avoid namespace issues in future... > > > + > > +struct mhi_net_stats { > > + u64_stats_t rx_packets; > > + u64_stats_t rx_bytes; > > + u64_stats_t rx_errors; > > + u64_stats_t rx_dropped; > > + u64_stats_t tx_packets; > > + u64_stats_t tx_bytes; > > + u64_stats_t tx_errors; > > + u64_stats_t tx_dropped; > > + atomic_t rx_queued; > > + struct u64_stats_sync tx_syncp; > > + struct u64_stats_sync rx_syncp; > > +}; > > + > > +struct mhi_net_dev { > > + struct mhi_device *mdev; > > + struct net_device *ndev; > > + struct delayed_work rx_refill; > > + struct mhi_net_stats stats; > > + u32 rx_queue_sz; > > +}; > > + > > [...] > > > +static void mhi_net_rx_refill_work(struct work_struct *work) > > +{ > > + struct mhi_net_dev *mhi_netdev = container_of(work, struct mhi_net_dev, > > + rx_refill.work); > > + struct net_device *ndev = mhi_netdev->ndev; > > + struct mhi_device *mdev = mhi_netdev->mdev; > > + int size = READ_ONCE(ndev->mtu); > > + struct sk_buff *skb; > > + int err; > > + > > + do { > > + skb = netdev_alloc_skb(ndev, size); > > + if (unlikely(!skb)) > > + break; > > + > > + err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb, size, MHI_EOT); > > + if (unlikely(err)) { > > + net_err_ratelimited("%s: Failed to queue RX buf (%d)\n", > > + ndev->name, err); > > + kfree_skb(skb); > > + break; > > + } > > + > > + /* Do not hog the CPU if rx buffers are completed faster than > > + * queued (unlikely). > > s/completed/consumed > > > + */ > > + cond_resched(); > > + } while (atomic_inc_return(&mhi_netdev->stats.rx_queued) < mhi_netdev->rx_queue_sz); > > + > > + /* If we're still starved of rx buffers, reschedule later */ > > + if (unlikely(!atomic_read(&mhi_netdev->stats.rx_queued))) > > + schedule_delayed_work(&mhi_netdev->rx_refill, HZ / 2); > > +} > > + > > +static int mhi_net_probe(struct mhi_device *mhi_dev, > > + const struct mhi_device_id *id) > > +{ > > + const char *netname = (char *)id->driver_data; > > + struct mhi_net_dev *mhi_netdev; > > + struct net_device *ndev; > > + struct device *dev = &mhi_dev->dev; > > + int err; > > Since this is a networking driver, please stick to reverse xmas tree order for > local variables.
On Wed, Oct 28, 2020 at 05:34:58PM +0100, Loic Poulain wrote: > This patch adds a new network driver implementing MHI transport for > network packets. Packets can be in any format, though QMAP (rmnet) > is the usual protocol (flow control + PDN mux). > > It support two MHI devices, IP_HW0 which is, the path to the IPA > (IP accelerator) on qcom modem, And IP_SW0 which is the software > driven IP path (to modem CPU). > > Signed-off-by: Loic Poulain <loic.poulain@linaro.org> > --- > v2: - rebase on net-next > - remove useless skb_linearize > - check error type on mhi_queue return > - rate limited errors > - Schedule RX refill only on 'low' buf level > - SET_NETDEV_DEV in probe > - reorder device remove sequence > v3: - Stop channels on net_register error > - Remove useles parentheses > - Add driver .owner > v4: - prevent potential cpu hog in rx-refill loop > - Access mtu via READ_ONCE > v5: - Fix access to u64 stats > v6: - Stop TX queue earlier if queue is full > - Preventing 'abnormal' NETDEV_TX_BUSY path > v7: - Stop dl/ul cb operations on channel resetting > v8: - remove premature comment about TX threading gain > - check rx_queued to determine queuing limits > - fix probe error path (unified goto usage) > > drivers/net/Kconfig | 7 ++ > drivers/net/Makefile | 1 + > drivers/net/mhi_net.c | 313 ++++++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 321 insertions(+) > create mode 100644 drivers/net/mhi_net.c > [...] > +static int mhi_net_probe(struct mhi_device *mhi_dev, > + const struct mhi_device_id *id) > +{ > + const char *netname = (char *)id->driver_data; > + struct mhi_net_dev *mhi_netdev; > + struct net_device *ndev; > + struct device *dev = &mhi_dev->dev; > + int err; > + > + ndev = alloc_netdev(sizeof(*mhi_netdev), netname, NET_NAME_PREDICTABLE, > + mhi_net_setup); > + if (!ndev) > + return -ENOMEM; > + > + mhi_netdev = netdev_priv(ndev); > + dev_set_drvdata(dev, mhi_netdev); > + mhi_netdev->ndev = ndev; > + mhi_netdev->mdev = mhi_dev; > + SET_NETDEV_DEV(ndev, &mhi_dev->dev); > + > + /* All MHI net channels have 128 ring elements (at least for now) */ > + mhi_netdev->rx_queue_sz = 128; > + > + INIT_DELAYED_WORK(&mhi_netdev->rx_refill, mhi_net_rx_refill_work); > + u64_stats_init(&mhi_netdev->stats.rx_syncp); > + u64_stats_init(&mhi_netdev->stats.tx_syncp); > + > + /* Start MHI channels */ > + err = mhi_prepare_for_transfer(mhi_dev); > + if (err) > + goto out_prep_err; > + > + err = register_netdev(ndev); > + if (err) > + goto out_register_err; > + > + return 0; > + > +out_register_err: > + mhi_unprepare_from_transfer(mhi_dev); Missed this one. MHI stack will do this for you incase of failure. Thanks, Mani
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index 1368d1d..11a6357 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -426,6 +426,13 @@ config VSOCKMON mostly intended for developers or support to debug vsock issues. If unsure, say N. +config MHI_NET + tristate "MHI network driver" + depends on MHI_BUS + help + This is the network driver for MHI. It can be used with + QCOM based WWAN modems (like SDX55). Say Y or M. + endif # NET_CORE config SUNGEM_PHY diff --git a/drivers/net/Makefile b/drivers/net/Makefile index 94b6080..8312037 100644 --- a/drivers/net/Makefile +++ b/drivers/net/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_GTP) += gtp.o obj-$(CONFIG_NLMON) += nlmon.o obj-$(CONFIG_NET_VRF) += vrf.o obj-$(CONFIG_VSOCKMON) += vsockmon.o +obj-$(CONFIG_MHI_NET) += mhi_net.o # # Networking Drivers diff --git a/drivers/net/mhi_net.c b/drivers/net/mhi_net.c new file mode 100644 index 0000000..4ba146d --- /dev/null +++ b/drivers/net/mhi_net.c @@ -0,0 +1,313 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* MHI Network driver - Network over MHI + * + * Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org> + */ + +#include <linux/if_arp.h> +#include <linux/mhi.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/netdevice.h> +#include <linux/skbuff.h> +#include <linux/u64_stats_sync.h> + +#define MIN_MTU ETH_MIN_MTU +#define MAX_MTU 0xffff +#define DEFAULT_MTU 16384 + +struct mhi_net_stats { + u64_stats_t rx_packets; + u64_stats_t rx_bytes; + u64_stats_t rx_errors; + u64_stats_t rx_dropped; + u64_stats_t tx_packets; + u64_stats_t tx_bytes; + u64_stats_t tx_errors; + u64_stats_t tx_dropped; + atomic_t rx_queued; + struct u64_stats_sync tx_syncp; + struct u64_stats_sync rx_syncp; +}; + +struct mhi_net_dev { + struct mhi_device *mdev; + struct net_device *ndev; + struct delayed_work rx_refill; + struct mhi_net_stats stats; + u32 rx_queue_sz; +}; + +static int mhi_ndo_open(struct net_device *ndev) +{ + struct mhi_net_dev *mhi_netdev = netdev_priv(ndev); + + /* Feed the rx buffer pool */ + schedule_delayed_work(&mhi_netdev->rx_refill, 0); + + /* Carrier is established via out-of-band channel (e.g. qmi) */ + netif_carrier_on(ndev); + + netif_start_queue(ndev); + + return 0; +} + +static int mhi_ndo_stop(struct net_device *ndev) +{ + struct mhi_net_dev *mhi_netdev = netdev_priv(ndev); + + netif_stop_queue(ndev); + netif_carrier_off(ndev); + cancel_delayed_work_sync(&mhi_netdev->rx_refill); + + return 0; +} + +static int mhi_ndo_xmit(struct sk_buff *skb, struct net_device *ndev) +{ + struct mhi_net_dev *mhi_netdev = netdev_priv(ndev); + struct mhi_device *mdev = mhi_netdev->mdev; + int err; + + err = mhi_queue_skb(mdev, DMA_TO_DEVICE, skb, skb->len, MHI_EOT); + if (unlikely(err)) { + net_err_ratelimited("%s: Failed to queue TX buf (%d)\n", + ndev->name, err); + + u64_stats_update_begin(&mhi_netdev->stats.tx_syncp); + u64_stats_inc(&mhi_netdev->stats.tx_dropped); + u64_stats_update_end(&mhi_netdev->stats.tx_syncp); + + /* drop the packet */ + kfree_skb(skb); + } + + if (mhi_queue_is_full(mdev, DMA_TO_DEVICE)) + netif_stop_queue(ndev); + + return NETDEV_TX_OK; +} + +static void mhi_ndo_get_stats64(struct net_device *ndev, + struct rtnl_link_stats64 *stats) +{ + struct mhi_net_dev *mhi_netdev = netdev_priv(ndev); + unsigned int start; + + do { + start = u64_stats_fetch_begin_irq(&mhi_netdev->stats.rx_syncp); + stats->rx_packets = u64_stats_read(&mhi_netdev->stats.rx_packets); + stats->rx_bytes = u64_stats_read(&mhi_netdev->stats.rx_bytes); + stats->rx_errors = u64_stats_read(&mhi_netdev->stats.rx_errors); + stats->rx_dropped = u64_stats_read(&mhi_netdev->stats.rx_dropped); + } while (u64_stats_fetch_retry_irq(&mhi_netdev->stats.rx_syncp, start)); + + do { + start = u64_stats_fetch_begin_irq(&mhi_netdev->stats.tx_syncp); + stats->tx_packets = u64_stats_read(&mhi_netdev->stats.tx_packets); + stats->tx_bytes = u64_stats_read(&mhi_netdev->stats.tx_bytes); + stats->tx_errors = u64_stats_read(&mhi_netdev->stats.tx_errors); + stats->tx_dropped = u64_stats_read(&mhi_netdev->stats.tx_dropped); + } while (u64_stats_fetch_retry_irq(&mhi_netdev->stats.tx_syncp, start)); +} + +static const struct net_device_ops mhi_netdev_ops = { + .ndo_open = mhi_ndo_open, + .ndo_stop = mhi_ndo_stop, + .ndo_start_xmit = mhi_ndo_xmit, + .ndo_get_stats64 = mhi_ndo_get_stats64, +}; + +static void mhi_net_setup(struct net_device *ndev) +{ + ndev->header_ops = NULL; /* No header */ + ndev->type = ARPHRD_NONE; /* QMAP... */ + ndev->hard_header_len = 0; + ndev->addr_len = 0; + ndev->flags = IFF_POINTOPOINT | IFF_NOARP; + ndev->netdev_ops = &mhi_netdev_ops; + ndev->mtu = DEFAULT_MTU; + ndev->min_mtu = MIN_MTU; + ndev->max_mtu = MAX_MTU; + ndev->tx_queue_len = 1000; +} + +static void mhi_net_dl_callback(struct mhi_device *mhi_dev, + struct mhi_result *mhi_res) +{ + struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev); + struct sk_buff *skb = mhi_res->buf_addr; + int remaining; + + remaining = atomic_dec_return(&mhi_netdev->stats.rx_queued); + + if (unlikely(mhi_res->transaction_status)) { + u64_stats_update_begin(&mhi_netdev->stats.rx_syncp); + u64_stats_inc(&mhi_netdev->stats.rx_errors); + u64_stats_update_end(&mhi_netdev->stats.rx_syncp); + + kfree_skb(skb); + + /* MHI layer resetting the DL channel */ + if (mhi_res->transaction_status == -ENOTCONN) + return; + } else { + u64_stats_update_begin(&mhi_netdev->stats.rx_syncp); + u64_stats_inc(&mhi_netdev->stats.rx_packets); + u64_stats_add(&mhi_netdev->stats.rx_bytes, mhi_res->bytes_xferd); + u64_stats_update_end(&mhi_netdev->stats.rx_syncp); + + skb->protocol = htons(ETH_P_MAP); + skb_put(skb, mhi_res->bytes_xferd); + netif_rx(skb); + } + + /* Refill if RX buffers queue becomes low */ + if (remaining <= mhi_netdev->rx_queue_sz / 2) + schedule_delayed_work(&mhi_netdev->rx_refill, 0); +} + +static void mhi_net_ul_callback(struct mhi_device *mhi_dev, + struct mhi_result *mhi_res) +{ + struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev); + struct net_device *ndev = mhi_netdev->ndev; + struct sk_buff *skb = mhi_res->buf_addr; + + /* Hardware has consumed the buffer, so free the skb (which is not + * freed by the MHI stack) and perform accounting. + */ + consume_skb(skb); + + u64_stats_update_begin(&mhi_netdev->stats.tx_syncp); + if (unlikely(mhi_res->transaction_status)) { + u64_stats_inc(&mhi_netdev->stats.tx_errors); + + /* MHI layer resetting the UL channel */ + if (mhi_res->transaction_status == -ENOTCONN) + return; + } else { + u64_stats_inc(&mhi_netdev->stats.tx_packets); + u64_stats_add(&mhi_netdev->stats.tx_bytes, mhi_res->bytes_xferd); + } + u64_stats_update_end(&mhi_netdev->stats.tx_syncp); + + if (netif_queue_stopped(ndev)) + netif_wake_queue(ndev); +} + +static void mhi_net_rx_refill_work(struct work_struct *work) +{ + struct mhi_net_dev *mhi_netdev = container_of(work, struct mhi_net_dev, + rx_refill.work); + struct net_device *ndev = mhi_netdev->ndev; + struct mhi_device *mdev = mhi_netdev->mdev; + int size = READ_ONCE(ndev->mtu); + struct sk_buff *skb; + int err; + + do { + skb = netdev_alloc_skb(ndev, size); + if (unlikely(!skb)) + break; + + err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb, size, MHI_EOT); + if (unlikely(err)) { + net_err_ratelimited("%s: Failed to queue RX buf (%d)\n", + ndev->name, err); + kfree_skb(skb); + break; + } + + /* Do not hog the CPU if rx buffers are completed faster than + * queued (unlikely). + */ + cond_resched(); + } while (atomic_inc_return(&mhi_netdev->stats.rx_queued) < mhi_netdev->rx_queue_sz); + + /* If we're still starved of rx buffers, reschedule later */ + if (unlikely(!atomic_read(&mhi_netdev->stats.rx_queued))) + schedule_delayed_work(&mhi_netdev->rx_refill, HZ / 2); +} + +static int mhi_net_probe(struct mhi_device *mhi_dev, + const struct mhi_device_id *id) +{ + const char *netname = (char *)id->driver_data; + struct mhi_net_dev *mhi_netdev; + struct net_device *ndev; + struct device *dev = &mhi_dev->dev; + int err; + + ndev = alloc_netdev(sizeof(*mhi_netdev), netname, NET_NAME_PREDICTABLE, + mhi_net_setup); + if (!ndev) + return -ENOMEM; + + mhi_netdev = netdev_priv(ndev); + dev_set_drvdata(dev, mhi_netdev); + mhi_netdev->ndev = ndev; + mhi_netdev->mdev = mhi_dev; + SET_NETDEV_DEV(ndev, &mhi_dev->dev); + + /* All MHI net channels have 128 ring elements (at least for now) */ + mhi_netdev->rx_queue_sz = 128; + + INIT_DELAYED_WORK(&mhi_netdev->rx_refill, mhi_net_rx_refill_work); + u64_stats_init(&mhi_netdev->stats.rx_syncp); + u64_stats_init(&mhi_netdev->stats.tx_syncp); + + /* Start MHI channels */ + err = mhi_prepare_for_transfer(mhi_dev); + if (err) + goto out_prep_err; + + err = register_netdev(ndev); + if (err) + goto out_register_err; + + return 0; + +out_register_err: + mhi_unprepare_from_transfer(mhi_dev); +out_prep_err: + free_netdev(ndev); + return err; +} + +static void mhi_net_remove(struct mhi_device *mhi_dev) +{ + struct mhi_net_dev *mhi_netdev = dev_get_drvdata(&mhi_dev->dev); + + unregister_netdev(mhi_netdev->ndev); + + mhi_unprepare_from_transfer(mhi_netdev->mdev); + + free_netdev(mhi_netdev->ndev); +} + +static const struct mhi_device_id mhi_net_id_table[] = { + { .chan = "IP_HW0", .driver_data = (kernel_ulong_t)"mhi_hwip%d" }, + { .chan = "IP_SW0", .driver_data = (kernel_ulong_t)"mhi_swip%d" }, + {} +}; +MODULE_DEVICE_TABLE(mhi, mhi_net_id_table); + +static struct mhi_driver mhi_net_driver = { + .probe = mhi_net_probe, + .remove = mhi_net_remove, + .dl_xfer_cb = mhi_net_dl_callback, + .ul_xfer_cb = mhi_net_ul_callback, + .id_table = mhi_net_id_table, + .driver = { + .name = "mhi_net", + .owner = THIS_MODULE, + }, +}; + +module_mhi_driver(mhi_net_driver); + +MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>"); +MODULE_DESCRIPTION("Network over MHI"); +MODULE_LICENSE("GPL v2");
This patch adds a new network driver implementing MHI transport for network packets. Packets can be in any format, though QMAP (rmnet) is the usual protocol (flow control + PDN mux). It support two MHI devices, IP_HW0 which is, the path to the IPA (IP accelerator) on qcom modem, And IP_SW0 which is the software driven IP path (to modem CPU). Signed-off-by: Loic Poulain <loic.poulain@linaro.org> --- v2: - rebase on net-next - remove useless skb_linearize - check error type on mhi_queue return - rate limited errors - Schedule RX refill only on 'low' buf level - SET_NETDEV_DEV in probe - reorder device remove sequence v3: - Stop channels on net_register error - Remove useles parentheses - Add driver .owner v4: - prevent potential cpu hog in rx-refill loop - Access mtu via READ_ONCE v5: - Fix access to u64 stats v6: - Stop TX queue earlier if queue is full - Preventing 'abnormal' NETDEV_TX_BUSY path v7: - Stop dl/ul cb operations on channel resetting v8: - remove premature comment about TX threading gain - check rx_queued to determine queuing limits - fix probe error path (unified goto usage) drivers/net/Kconfig | 7 ++ drivers/net/Makefile | 1 + drivers/net/mhi_net.c | 313 ++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 321 insertions(+) create mode 100644 drivers/net/mhi_net.c