From patchwork Fri Oct 30 10:48:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Loic Poulain X-Patchwork-Id: 11869205 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F08E392C for ; Fri, 30 Oct 2020 10:42:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A7CF620723 for ; Fri, 30 Oct 2020 10:42:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="EHkwB/ec" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725808AbgJ3Kmc (ORCPT ); Fri, 30 Oct 2020 06:42:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725801AbgJ3Kmb (ORCPT ); Fri, 30 Oct 2020 06:42:31 -0400 Received: from mail-wm1-x343.google.com (mail-wm1-x343.google.com [IPv6:2a00:1450:4864:20::343]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 563E1C0613CF for ; Fri, 30 Oct 2020 03:42:31 -0700 (PDT) Received: by mail-wm1-x343.google.com with SMTP id k18so2487601wmj.5 for ; Fri, 30 Oct 2020 03:42:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id; bh=7SKRcpJBDvushs/+KG/I886TAzE11R66+iefP6d6//k=; b=EHkwB/eciqRteK4HAhD6P/7oTDJmvnFmSsaez+AhbmGfrRV9kULlnghrMcq+YP6q33 s5LOqOBhIrwzTlqyxfLKP6Ozf995HBZyN3Ulhg3PjzmvoOpms/EmJM/l/7xx/ERxAQ8o Gw6emh2q3TmCEtNtuqM7zaxSjJ2VNuM2UmLTL+A6rlGnfI36QxA8ShT/cQbiTm/WS7XL EbaWS17SLMPKi4rquG7OZVbqwYLzAJncV5oVsDt6zeZVJgIMnoyVSj0Dyakw7yY/LxOh CqmhA0nIaCFGJhP0mCmXTt7OYpaNCfikjcZA9N8Cma5RUVeSs4Uy/0rzx2TnXhHPUh/W SI/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=7SKRcpJBDvushs/+KG/I886TAzE11R66+iefP6d6//k=; b=mp8N2YvJ3lj+cBFfSJsQFVgcwRMpjXM40BEWRudcp7aeUFbwltXcwsPHnumXfchXh9 b+y8F03NCTp7twk5+X0liwLMWSnJ3btL90/B1j/t/JMnz/dsTvhQsHamopJJNv1AxX6p go03KkwTBodYZYQsAZBG3BjzbZ4Sx39T/QphYWod1uOrQ3lZHeUfKPKOotqvtzBoaJUk cL3LFx3nRYlsWBb8H/0CtZtZzWDYfNQCf1eY8B1XJ69830Cg7faKCetQVfG6jFvBBvWh aEuZpR0sjhe7CZQHpyRkmLL2xqJ+NhoV3pZMpam3cS7D8vNCqNZ4WcqyUCSChbEDC+/6 hIcQ== X-Gm-Message-State: AOAM532y7Yq0GLv8wOX2IDkfhuJIFwPivU08apHjffyAv7vMqbwtTBuJ jp599nnlPq83Sm5OdBidjG5jNQ== X-Google-Smtp-Source: ABdhPJx0Kj4GfYsccW1P4lggo0r5MHZGosTnyD2u8T618g+U7exPgFvDZLMpzVmO7D+5Dhp7qYQdDw== X-Received: by 2002:a1c:740f:: with SMTP id p15mr1898330wmc.106.1604054549973; Fri, 30 Oct 2020 03:42:29 -0700 (PDT) Received: from localhost.localdomain ([88.122.66.28]) by smtp.gmail.com with ESMTPSA id l26sm4060567wmi.39.2020.10.30.03.42.23 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 30 Oct 2020 03:42:29 -0700 (PDT) From: Loic Poulain To: kuba@kernel.org, davem@davemloft.net Cc: netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org, bbhatt@codeaurora.org, willemdebruijn.kernel@gmail.com, jhugo@codeaurora.org, manivannan.sadhasivam@linaro.org, hemantk@codeaurora.org, Loic Poulain Subject: [PATCH v9 2/2] net: Add mhi-net driver Date: Fri, 30 Oct 2020 11:48:15 +0100 Message-Id: <1604054895-29137-1-git-send-email-loic.poulain@linaro.org> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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 Reviewed-by: Manivannan Sadhasivam --- 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) v9: - fix coding style and comments for MHI bus - remove useless mhi_unprepare in probe (done by mhi core) drivers/net/Kconfig | 7 ++ drivers/net/Makefile | 1 + drivers/net/mhi_net.c | 311 ++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 319 insertions(+) create mode 100644 drivers/net/mhi_net.c diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index 1368d1d..ef830ed 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 bus. 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..9136085 --- /dev/null +++ b/drivers/net/mhi_net.c @@ -0,0 +1,311 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* MHI Network driver - Network over MHI bus + * + * Copyright (C) 2020 Linaro Ltd + */ + +#include +#include +#include +#include +#include +#include +#include + +#define MHI_NET_MIN_MTU ETH_MIN_MTU +#define MHI_NET_MAX_MTU 0xffff +#define MHI_NET_DEFAULT_MTU 0x4000 + +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 = MHI_NET_DEFAULT_MTU; + ndev->min_mtu = MHI_NET_MIN_MTU; + ndev->max_mtu = MHI_NET_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 consumed 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 device *dev = &mhi_dev->dev; + struct mhi_net_dev *mhi_netdev; + struct net_device *ndev; + 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_err; + + err = register_netdev(ndev); + if (err) + goto out_err; + + return 0; + +out_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 "); +MODULE_DESCRIPTION("Network over MHI"); +MODULE_LICENSE("GPL v2");