[v5,3/3] mctp: Add MCTP-over-KCS transport binding

Message ID	20231010122321.823-4-aladyshev22@gmail.com
State	Handled Elsewhere, archived
Headers	show Return-Path: <linux-aspeed-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org> From: Konstantin Aladyshev <aladyshev22@gmail.com> To: Subject: [PATCH v5 3/3] mctp: Add MCTP-over-KCS transport binding Date: Tue, 10 Oct 2023 15:23:21 +0300 Message-Id: <20231010122321.823-4-aladyshev22@gmail.com> In-Reply-To: <20231010122321.823-1-aladyshev22@gmail.com> References: <20231010122321.823-1-aladyshev22@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: list Cc: tmaimon77@gmail.com, linux-aspeed@lists.ozlabs.org, tali.perry1@gmail.com, edumazet@google.com, jk@codeconstruct.com.au, matt@codeconstruct.com.au, openbmc@lists.ozlabs.org, yuenn@google.com, kuba@kernel.org, pabeni@redhat.com, minyard@acm.org, aladyshev22@gmail.com, openipmi-developer@lists.sourceforge.net, linux-arm-kernel@lists.infradead.org, venture@google.com, linux-kernel@vger.kernel.org, avifishman70@gmail.com, netdev@vger.kernel.org, davem@davemloft.net Errors-To: linux-aspeed-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linux-aspeed" <linux-aspeed-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org>
Series	Add MCTP-over-KCS transport binding \| expand [v5,0/3] Add MCTP-over-KCS transport binding [v5,1/3] ipmi: Move KCS headers to common include folder [v5,2/3] ipmi: Create header with KCS interface defines [v5,3/3] mctp: Add MCTP-over-KCS transport binding

On Tue, 10 Oct 2023 15:23:21 +0300 Konstantin Aladyshev <aladyshev22@gmail.com> wrote: > This change adds a MCTP KCS transport binding, as defined by the DMTF > specification DSP0254 - "MCTP KCS Transport Binding". > A MCTP protocol network device is created for each KCS channel found in > the system. > The interrupt code for the KCS state machine is based on the current > IPMI KCS driver. > > Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com> Hi Konstantin. Many of the comments I have inline will be more about general KCS issues that need sorting out. Whether this can move forwards before that (or whether to take any noticed of this) is a question for relevant maintainers. BTW it's fine to propose fixes /cleanup to a subsystem alongside a new driver if you do fancy taking on some of the issues with managed allocations etc called out. Jonathan > diff --git a/drivers/net/mctp/mctp-kcs.c b/drivers/net/mctp/mctp-kcs.c > new file mode 100644 > index 000000000000..b0d903609c64 > --- /dev/null > +++ b/drivers/net/mctp/mctp-kcs.c > @@ -0,0 +1,600 @@ ... > + > +static DEFINE_SPINLOCK(kcs_bmc_mctp_instances_lock); > +static LIST_HEAD(kcs_bmc_mctp_instances); > + > +static int kcs_bmc_mctp_add_device(struct kcs_bmc_device *kcs_bmc) > +{ > + struct net_device *ndev; > + struct mctp_kcs *mkcs; > + char name[32]; > + int rc; > + > + snprintf(name, sizeof(name), "mctpkcs%d", kcs_bmc->channel); > + > + ndev = alloc_netdev(sizeof(*mkcs), name, NET_NAME_ENUM, mctp_kcs_setup); > + if (!ndev) { > + dev_err_probe(kcs_bmc->dev, -ENOMEM, > + "alloc_netdev failed for KCS channel %d\n", > + kcs_bmc->channel); > + return -ENOMEM; > + } > + > + mkcs = netdev_priv(ndev); > + mkcs->netdev = ndev; > + mkcs->client.dev = kcs_bmc; > + mkcs->client.ops = &kcs_bmc_mctp_client_ops; > + mkcs->data_in = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL); > + if (!mkcs->data_in) { > + dev_err_probe( > + kcs_bmc->dev, -ENOMEM, > + "failed to allocate data_in buffer for KCS channel %d\n", > + kcs_bmc->channel); > + rc = -ENOMEM; > + goto free_netdev; > + } > + mkcs->data_out = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL); > + if (!mkcs->data_out) { > + dev_err_probe( > + kcs_bmc->dev, -ENOMEM, > + "failed to allocate data_out buffer for KCS channel %d\n", > + kcs_bmc->channel); > + rc = -ENOMEM; > + goto free_netdev; > + } > + > + INIT_WORK(&mkcs->rx_work, mctp_kcs_rx_work); > + > + rc = register_netdev(ndev); > + if (rc) > + goto free_netdev; > + > + spin_lock_irq(&kcs_bmc_mctp_instances_lock); > + list_add(&mkcs->entry, &kcs_bmc_mctp_instances); > + spin_unlock_irq(&kcs_bmc_mctp_instances_lock); > + > + dev_info(kcs_bmc->dev, "Add MCTP client for the KCS channel %d", > + kcs_bmc->channel); > + return 0; > + > +free_netdev: > + free_netdev(ndev); Mixing devm and non devm is something you should not do. Very simple rule that must be kept to is that you stop using devm for any calls in an add_device / probe() function at the first line that needs manual cleanup. Use devm_add_action_or_reset() for this case as you can add a custom callback to the devm managed queue. The reason this all matters is that devm cleanup happens after error paths / remove_device() callbacks and as such it makes a reviewer have to reason about whether there are any dependencies that are a result of the reordering. Tearing down in exact reverse order of setup is a lot easier to do! > + > + return rc; > +} > + > +static int kcs_bmc_mctp_remove_device(struct kcs_bmc_device *kcs_bmc) > +{ > + struct mctp_kcs *mkcs = NULL, *pos; > + > + dev_info(kcs_bmc->dev, "Remove MCTP client for the KCS channel %d", > + kcs_bmc->channel); > + spin_lock_irq(&kcs_bmc_mctp_instances_lock); > + list_for_each_entry(pos, &kcs_bmc_mctp_instances, entry) { I've commented on this before, but this lookup should not be necessary. It should be possible to go directly from kcs_bmc entry as registered to the mctp_kcs structure. Typical approach being to embed the structure or using some drvdata type field that add has filled in with appropriate pointer. There is a need for the kcs subsystem to manage which devices it calls this on. Currently this also serves the purpose of filtering for that. If not going to do management at subsystem layer (some smaller subsystems don't) then use an enum to add a type to kcs_bmc and have each driver add a new one. You can check that in driver or in core code. Doesn't matter which as check will be trivial. > + if (pos->client.dev == kcs_bmc) { > + mkcs = pos; > + list_del(&pos->entry); > + break; > + } > + } > + spin_unlock_irq(&kcs_bmc_mctp_instances_lock); > + > + if (!mkcs) > + return -ENODEV; > + > + unregister_netdev(mkcs->netdev); > + free_netdev(mkcs->netdev); > + kcs_bmc_disable_device(kcs_bmc, &mkcs->client); > + devm_kfree(kcs_bmc->dev, mkcs->data_out); > + devm_kfree(kcs_bmc->dev, mkcs->data_in); I don't like mixture of letting devm delete these on remove and it being done manually here. Note that if you just didn't have these two calls, they'd be deleted soon after this exit anyway. If devm is any use when combined with kcs, these will be freed shortly after this anyway. If it isn't of use with this subsystem then then they won't do the right thing in the add_device callback error cases. I'd test if it does anything at all via each path where we'd expect it to (driver unbind, device removal, error in add_device callback) In all those cases the devm unwinding callbacks should be called. (add a bonus one for testing with devm_add_action_or_reset() and see if that one is called in each path). I'm very suspicious of this working as not setting the normal calls to make it happen. e.g. for I2c, it happens here: https://elixir.bootlin.com/linux/latest/source/drivers/i2c/i2c-core-base.c#L597 for the error path with a call to devres_release_group() in other subsystems it's handled by the bus_type logic which ultimately calls device_unbind_cleanup() in probe() failure. That calls devres_release_all() triggering the tear down paths. However I might be missing a route by which the cleanup happens. Anyhow, if that is fixed, these devm cleanup calls in remove_device() should not be here. The whole point of devm is to simplify this - if you manually have to unwind it the advantages go away and you should manage things explicitly. > + return 0; > +} > + > +static const struct kcs_bmc_driver_ops kcs_bmc_mctp_driver_ops = { > + .add_device = kcs_bmc_mctp_add_device, > + .remove_device = kcs_bmc_mctp_remove_device, > +}; > + > +static struct kcs_bmc_driver kcs_bmc_mctp_driver = { > + .ops = &kcs_bmc_mctp_driver_ops, > +}; > + > +static int __init mctp_kcs_init(void) > +{ > + kcs_bmc_register_driver(&kcs_bmc_mctp_driver); > + return 0; > +} > + > +static void __exit mctp_kcs_exit(void) > +{ > + kcs_bmc_unregister_driver(&kcs_bmc_mctp_driver); > +} > + > +module_init(mctp_kcs_init); > +module_exit(mctp_kcs_exit); > + > +MODULE_LICENSE("GPL"); > +MODULE_AUTHOR("Konstantin Aladyshev <aladyshev22@gmail.com>"); > +MODULE_DESCRIPTION("MCTP KCS transport");

diff --git a/drivers/net/mctp/Kconfig b/drivers/net/mctp/Kconfig index dc71657d9184..a37f7ba947c0 100644 --- a/drivers/net/mctp/Kconfig +++ b/drivers/net/mctp/Kconfig @@ -33,6 +33,14 @@ config MCTP_TRANSPORT_I2C from DMTF specification DSP0237. A MCTP protocol network device is created for each I2C bus that has been assigned a mctp-i2c device. +config MCTP_TRANSPORT_KCS + tristate "MCTP KCS transport" + depends on IPMI_KCS_BMC + help + Provides a driver to access MCTP devices over KCS transport, from + DMTF specification DSP0254. A MCTP protocol network device is + created for each KCS channel found in the system. + endmenu endif diff --git a/drivers/net/mctp/Makefile b/drivers/net/mctp/Makefile index 1ca3e6028f77..885339a40f22 100644 --- a/drivers/net/mctp/Makefile +++ b/drivers/net/mctp/Makefile @@ -1,2 +1,3 @@ obj-$(CONFIG_MCTP_SERIAL) += mctp-serial.o obj-$(CONFIG_MCTP_TRANSPORT_I2C) += mctp-i2c.o +obj-$(CONFIG_MCTP_TRANSPORT_KCS) += mctp-kcs.o diff --git a/drivers/net/mctp/mctp-kcs.c b/drivers/net/mctp/mctp-kcs.c new file mode 100644 index 000000000000..b0d903609c64 --- /dev/null +++ b/drivers/net/mctp/mctp-kcs.c @@ -0,0 +1,600 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Management Component Transport Protocol (MCTP) KCS transport binding. + * This driver is an implementation of the DMTF specification + * "DSP0254 - Management Component Transport Protocol (MCTP) KCS Transport + * Binding", available at: + * + * https://www.dmtf.org/sites/default/files/standards/documents/DSP0254_1.0.0.pdf + * + * This driver provides DSP0254-type MCTP-over-KCS transport using a Linux + * KCS client subsystem. + * + * Copyright (c) 2023 Konstantin Aladyshev <aladyshev22@gmail.com> + */ + +#include <linux/i2c.h> +#include <linux/if_arp.h> +#include <linux/ipmi_kcs.h> +#include <linux/kcs_bmc_client.h> +#include <linux/mctp.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/netdevice.h> +#include <net/mctp.h> +#include <net/mctpdevice.h> +#include <net/pkt_sched.h> + +#define MCTP_KCS_MTU 64 +#define KCS_MSG_BUFSIZ 1000 + +struct mctp_kcs { + struct list_head entry; + + /* protects rx & tx state machines */ + spinlock_t lock; + + struct kcs_bmc_client client; + struct net_device *netdev; + + enum kcs_ipmi_phases phase; + enum kcs_ipmi_errors error; + + unsigned int data_in_idx; + u8 *data_in; + + unsigned int data_out_idx; + unsigned int data_out_len; + u8 *data_out; + + struct work_struct rx_work; +}; + +struct mctp_kcs_header { + u8 netfn_lun; + u8 defining_body; + u8 len; +} __packed; + +struct mctp_kcs_trailer { + u8 pec; +} __packed; + +#define MCTP_KCS_NETFN_LUN 0xb0 +#define DEFINING_BODY_DMTF_PRE_OS_WORKING_GROUP 0x01 + +static int mctp_kcs_validate_data(struct mctp_kcs *mkcs, u8 *data, + unsigned int len) +{ + struct mctp_kcs_header *hdr = (struct mctp_kcs_header *)data; + struct net_device *ndev = mkcs->netdev; + struct mctp_kcs_trailer *tlr; + u8 pec; + + if (len < (sizeof(struct mctp_kcs_header) + + sizeof(struct mctp_kcs_trailer))) { + dev_err(mkcs->client.dev->dev, + "%s: error! Received data size (%d) is less than binding structs size (%d)", + __func__, len, + sizeof(struct mctp_kcs_header) + + sizeof(struct mctp_kcs_trailer)); + ndev->stats.rx_length_errors++; + return -EINVAL; + } + if (hdr->netfn_lun != MCTP_KCS_NETFN_LUN) { + dev_err(mkcs->client.dev->dev, + "%s: KCS binding header error! netfn_lun = 0x%02x, but should be 0x%02x", + __func__, hdr->netfn_lun, MCTP_KCS_NETFN_LUN); + ndev->stats.rx_dropped++; + return -EINVAL; + } + if (hdr->defining_body != DEFINING_BODY_DMTF_PRE_OS_WORKING_GROUP) { + dev_err(mkcs->client.dev->dev, + "%s: KCS binding header error! defining_body = 0x%02x, but should be 0x%02x", + __func__, hdr->defining_body, + DEFINING_BODY_DMTF_PRE_OS_WORKING_GROUP); + ndev->stats.rx_dropped++; + return -EINVAL; + } + if (hdr->len != (u8)(len - sizeof(struct mctp_kcs_header) - + sizeof(struct mctp_kcs_trailer))) { + dev_err(mkcs->client.dev->dev, + "%s: KCS binding header error! len = 0x%02x, but should be 0x%02x", + __func__, hdr->len, + (u8)(len - sizeof(struct mctp_kcs_header) - + sizeof(struct mctp_kcs_trailer))); + ndev->stats.rx_length_errors++; + return -EINVAL; + } + + pec = i2c_smbus_pec(0, (u8 *)(hdr + 1), hdr->len); + tlr = (struct mctp_kcs_trailer *)((u8 *)(hdr + 1) + hdr->len); + if (pec != tlr->pec) { + dev_err(mkcs->client.dev->dev, + "%s: PEC error! Packet value=0x%02x, calculated value=0x%02x", + __func__, tlr->pec, pec); + ndev->stats.rx_crc_errors++; + return -EINVAL; + } + return 0; +} + +static void mctp_kcs_rx_work(struct work_struct *work) +{ + struct mctp_kcs *mkcs = container_of(work, struct mctp_kcs, rx_work); + struct mctp_skb_cb *cb; + unsigned int data_len; + struct sk_buff *skb; + unsigned long flags; + unsigned int i; + int rc; + + spin_lock_irqsave(&mkcs->lock, flags); + for (i = 0; i < (mkcs->data_in_idx); i++) + dev_dbg(mkcs->client.dev->dev, "%s: data_in[%d]=0x%02x", + __func__, i, mkcs->data_in[i]); + + if (mkcs->phase != KCS_PHASE_WRITE_DONE) { + dev_err(mkcs->client.dev->dev, + "%s: error! Wrong KCS stage at the end of data read (phase=%d)", + __func__, mkcs->phase); + mkcs->netdev->stats.rx_dropped++; + goto unlock_irq; + } + + rc = mctp_kcs_validate_data(mkcs, mkcs->data_in, mkcs->data_in_idx); + if (rc) { + dev_err(mkcs->client.dev->dev, + "%s: error! Binding validation failed", __func__); + goto unlock_irq; + } + + data_len = mkcs->data_in_idx - sizeof(struct mctp_kcs_header) - + sizeof(struct mctp_kcs_trailer); + + skb = netdev_alloc_skb(mkcs->netdev, data_len); + if (!skb) { + mkcs->netdev->stats.rx_dropped++; + goto unlock_irq; + } + + skb->protocol = htons(ETH_P_MCTP); + skb_put_data(skb, mkcs->data_in + sizeof(struct mctp_kcs_header), + data_len); + skb_reset_network_header(skb); + + cb = __mctp_cb(skb); + cb->halen = 0; + + netif_rx(skb); + mkcs->netdev->stats.rx_packets++; + mkcs->netdev->stats.rx_bytes += data_len; + +unlock_irq: + mkcs->phase = KCS_PHASE_WAIT_READ; + mkcs->data_in_idx = 0; + spin_unlock_irqrestore(&mkcs->lock, flags); +} + +static netdev_tx_t mctp_kcs_start_xmit(struct sk_buff *skb, + struct net_device *ndev) +{ + struct mctp_kcs *mkcs = netdev_priv(ndev); + struct mctp_kcs_header *kcs_header; + unsigned long flags; + int i; + + if (skb->len > MCTP_KCS_MTU) { + dev_err(&ndev->dev, "%s: error! skb len is bigger than MTU", + __func__); + ndev->stats.tx_dropped++; + goto out; + } + + spin_lock_irqsave(&mkcs->lock, flags); + if (mkcs->phase != KCS_PHASE_WAIT_READ) { + dev_err(&ndev->dev, + "%s: error! Wrong KCS stage at the start of data write (phase=%d)", + __func__, mkcs->phase); + dev_kfree_skb(skb); + spin_unlock_irqrestore(&mkcs->lock, flags); + return NETDEV_TX_BUSY; + } + + netif_stop_queue(ndev); + mkcs->phase = KCS_PHASE_READ; + kcs_header = (struct mctp_kcs_header *)mkcs->data_out; + kcs_header->netfn_lun = MCTP_KCS_NETFN_LUN; + kcs_header->defining_body = DEFINING_BODY_DMTF_PRE_OS_WORKING_GROUP; + kcs_header->len = skb->len; + skb_copy_bits(skb, 0, kcs_header + 1, skb->len); + mkcs->data_out[sizeof(struct mctp_kcs_header) + skb->len] = + i2c_smbus_pec(0, (u8 *)(kcs_header + 1), skb->len); + mkcs->data_out_idx = 1; + mkcs->data_out_len = skb->len + sizeof(struct mctp_kcs_header) + + sizeof(struct mctp_kcs_trailer); + + for (i = 0; i < (mkcs->data_out_len); i++) + dev_dbg(&ndev->dev, "%s: data_out[%d]=0x%02x", __func__, i, + mkcs->data_out[i]); + + // Write first data byte to initialize transmission + kcs_bmc_write_data(mkcs->client.dev, mkcs->data_out[0]); + + spin_unlock_irqrestore(&mkcs->lock, flags); +out: + dev_kfree_skb(skb); + return NETDEV_TX_OK; +} + +static void set_state(struct mctp_kcs *mkcs, u8 state) +{ + dev_dbg(mkcs->client.dev->dev, "%s: state=0x%02x", __func__, state); + kcs_bmc_update_status(mkcs->client.dev, KCS_STATUS_STATE_MASK, + KCS_STATUS_STATE(state)); +} + +static int mctp_kcs_ndo_open(struct net_device *ndev) +{ + struct mctp_kcs *mkcs; + + mkcs = netdev_priv(ndev); + dev_info(&ndev->dev, "Open MCTP over KCS channel %d", + mkcs->client.dev->channel); + return kcs_bmc_enable_device(mkcs->client.dev, &mkcs->client); +} + +static int mctp_kcs_ndo_stop(struct net_device *ndev) +{ + struct mctp_kcs *mkcs; + + mkcs = netdev_priv(ndev); + dev_info(&ndev->dev, "Stop MCTP over KCS channel %d", + mkcs->client.dev->channel); + mkcs->data_in_idx = 0; + mkcs->data_out_idx = 0; + mkcs->data_out_len = 0; + mkcs->phase = KCS_PHASE_IDLE; + set_state(mkcs, IDLE_STATE); + kcs_bmc_disable_device(mkcs->client.dev, &mkcs->client); + return 0; +} + +static const struct net_device_ops mctp_kcs_netdev_ops = { + .ndo_start_xmit = mctp_kcs_start_xmit, + .ndo_open = mctp_kcs_ndo_open, + .ndo_stop = mctp_kcs_ndo_stop, +}; + +static void mctp_kcs_setup(struct net_device *ndev) +{ + ndev->type = ARPHRD_MCTP; + + /* we limit at the fixed MTU, which is also the MCTP-standard + * baseline MTU, so is also our minimum + */ + ndev->mtu = MCTP_KCS_MTU; + ndev->max_mtu = MCTP_KCS_MTU; + ndev->min_mtu = MCTP_KCS_MTU; + + ndev->hard_header_len = 0; + ndev->addr_len = 0; + ndev->tx_queue_len = DEFAULT_TX_QUEUE_LEN; + ndev->flags = IFF_NOARP; + ndev->netdev_ops = &mctp_kcs_netdev_ops; + ndev->needs_free_netdev = true; +} + +static void kcs_bmc_ipmi_force_abort(struct mctp_kcs *mkcs) +{ + dev_err(mkcs->client.dev->dev, + "Error! Force abort on KCS communication"); + set_state(mkcs, ERROR_STATE); + kcs_bmc_read_data(mkcs->client.dev); + kcs_bmc_write_data(mkcs->client.dev, KCS_ZERO_DATA); + mkcs->phase = KCS_PHASE_ERROR; + mkcs->data_in_idx = 0; +} + +static void kcs_bmc_ipmi_handle_data(struct mctp_kcs *mkcs) +{ + struct kcs_bmc_device *kcs_bmc = mkcs->client.dev; + u8 data; + + switch (mkcs->phase) { + case KCS_PHASE_WRITE_START: + dev_dbg(kcs_bmc->dev, "%s: KCS_PHASE_WRITE_START", __func__); + mkcs->phase = KCS_PHASE_WRITE_DATA; + fallthrough; + + case KCS_PHASE_WRITE_DATA: + dev_dbg(kcs_bmc->dev, "%s: KCS_PHASE_WRITE_DATA", __func__); + if (mkcs->data_in_idx < KCS_MSG_BUFSIZ) { + set_state(mkcs, WRITE_STATE); + kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA); + mkcs->data_in[mkcs->data_in_idx++] = + kcs_bmc_read_data(kcs_bmc); + dev_dbg(kcs_bmc->dev, + "%s: KCS_PHASE_WRITE_DATA: data_in[%d]=0x%02x", + __func__, mkcs->data_in_idx - 1, + mkcs->data_in[mkcs->data_in_idx - 1]); + } else { + kcs_bmc_ipmi_force_abort(mkcs); + mkcs->error = KCS_LENGTH_ERROR; + } + break; + + case KCS_PHASE_WRITE_END_CMD: + dev_dbg(kcs_bmc->dev, "%s: KCS_PHASE_WRITE_END_CMD", __func__); + if (mkcs->data_in_idx < KCS_MSG_BUFSIZ) { + set_state(mkcs, READ_STATE); + mkcs->data_in[mkcs->data_in_idx++] = + kcs_bmc_read_data(kcs_bmc); + dev_dbg(kcs_bmc->dev, + "%s: KCS_PHASE_WRITE_END_CMD: data_in[%d]=0x%02x", + __func__, mkcs->data_in_idx - 1, + mkcs->data_in[mkcs->data_in_idx - 1]); + mkcs->phase = KCS_PHASE_WRITE_DONE; + schedule_work(&mkcs->rx_work); + } else { + kcs_bmc_ipmi_force_abort(mkcs); + mkcs->error = KCS_LENGTH_ERROR; + } + break; + + case KCS_PHASE_READ: + dev_dbg(kcs_bmc->dev, + "%s: KCS_PHASE_READ, data_out_idx=%d, data_out_len=%d", + __func__, mkcs->data_out_idx, mkcs->data_out_len); + if (mkcs->data_out_idx == mkcs->data_out_len) + set_state(mkcs, IDLE_STATE); + + data = kcs_bmc_read_data(kcs_bmc); + if (data != KCS_CMD_READ_BYTE) { + dev_dbg(kcs_bmc->dev, + "%s: error! data is not equal to KCS_CMD_READ_BYTE", + __func__); + set_state(mkcs, ERROR_STATE); + kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA); + break; + } + + if (mkcs->data_out_idx == mkcs->data_out_len) { + kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA); + mkcs->netdev->stats.tx_bytes += mkcs->data_out_len; + mkcs->netdev->stats.tx_packets++; + mkcs->phase = KCS_PHASE_IDLE; + if (netif_queue_stopped(mkcs->netdev)) + netif_start_queue(mkcs->netdev); + break; + } + + dev_dbg(kcs_bmc->dev, "%s: KCS_PHASE_READ: data_out[%d]=0x%02x", + __func__, mkcs->data_out_idx, + mkcs->data_out[mkcs->data_out_idx]); + kcs_bmc_write_data(kcs_bmc, + mkcs->data_out[mkcs->data_out_idx++]); + break; + + case KCS_PHASE_ABORT_ERROR1: + dev_dbg(kcs_bmc->dev, "%s: KCS_PHASE_ABORT_ERROR1", __func__); + set_state(mkcs, READ_STATE); + kcs_bmc_read_data(kcs_bmc); + kcs_bmc_write_data(kcs_bmc, mkcs->error); + mkcs->phase = KCS_PHASE_ABORT_ERROR2; + break; + + case KCS_PHASE_ABORT_ERROR2: + dev_dbg(kcs_bmc->dev, "%s: KCS_PHASE_ABORT_ERROR2", __func__); + set_state(mkcs, IDLE_STATE); + kcs_bmc_read_data(kcs_bmc); + kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA); + mkcs->phase = KCS_PHASE_IDLE; + break; + + default: + dev_dbg(kcs_bmc->dev, "%s: unknown KCS phase", __func__); + kcs_bmc_ipmi_force_abort(mkcs); + break; + } +} + +static void kcs_bmc_ipmi_handle_cmd(struct mctp_kcs *mkcs) +{ + struct kcs_bmc_device *kcs_bmc = mkcs->client.dev; + + set_state(mkcs, WRITE_STATE); + kcs_bmc_write_data(kcs_bmc, KCS_ZERO_DATA); + + switch (kcs_bmc_read_data(kcs_bmc)) { + case KCS_CMD_WRITE_START: + dev_dbg(kcs_bmc->dev, "%s: KCS_CMD_WRITE_START", __func__); + mkcs->phase = KCS_PHASE_WRITE_START; + mkcs->error = KCS_NO_ERROR; + mkcs->data_in_idx = 0; + break; + + case KCS_CMD_WRITE_END: + dev_dbg(kcs_bmc->dev, "%s: KCS_CMD_WRITE_END", __func__); + if (mkcs->phase != KCS_PHASE_WRITE_DATA) { + kcs_bmc_ipmi_force_abort(mkcs); + break; + } + mkcs->phase = KCS_PHASE_WRITE_END_CMD; + break; + + case KCS_CMD_GET_STATUS_ABORT: + dev_dbg(kcs_bmc->dev, "%s: KCS_CMD_GET_STATUS_ABORT", __func__); + if (mkcs->error == KCS_NO_ERROR) + mkcs->error = KCS_ABORTED_BY_COMMAND; + + mkcs->phase = KCS_PHASE_ABORT_ERROR1; + mkcs->data_in_idx = 0; + break; + + default: + dev_dbg(kcs_bmc->dev, "%s: unknown KCS command", __func__); + kcs_bmc_ipmi_force_abort(mkcs); + mkcs->error = KCS_ILLEGAL_CONTROL_CODE; + break; + } +} + +static struct mctp_kcs *client_to_mctp_kcs(struct kcs_bmc_client *client) +{ + return container_of(client, struct mctp_kcs, client); +} + +static irqreturn_t kcs_bmc_mctp_event(struct kcs_bmc_client *client) +{ + struct mctp_kcs *mkcs; + u8 status; + int ret; + + mkcs = client_to_mctp_kcs(client); + if (!mkcs) { + dev_err(client->dev->dev, + "%s: error! can't find mctp_kcs from KCS client", + __func__); + return IRQ_NONE; + } + + spin_lock(&mkcs->lock); + + status = kcs_bmc_read_status(client->dev); + if (status & KCS_STATUS_IBF) { + if (status & KCS_STATUS_CMD_DAT) + kcs_bmc_ipmi_handle_cmd(mkcs); + else + kcs_bmc_ipmi_handle_data(mkcs); + + ret = IRQ_HANDLED; + } else { + ret = IRQ_NONE; + } + + spin_unlock(&mkcs->lock); + + return ret; +} + +static const struct kcs_bmc_client_ops kcs_bmc_mctp_client_ops = { + .event = kcs_bmc_mctp_event, +}; + +static DEFINE_SPINLOCK(kcs_bmc_mctp_instances_lock); +static LIST_HEAD(kcs_bmc_mctp_instances); + +static int kcs_bmc_mctp_add_device(struct kcs_bmc_device *kcs_bmc) +{ + struct net_device *ndev; + struct mctp_kcs *mkcs; + char name[32]; + int rc; + + snprintf(name, sizeof(name), "mctpkcs%d", kcs_bmc->channel); + + ndev = alloc_netdev(sizeof(*mkcs), name, NET_NAME_ENUM, mctp_kcs_setup); + if (!ndev) { + dev_err_probe(kcs_bmc->dev, -ENOMEM, + "alloc_netdev failed for KCS channel %d\n", + kcs_bmc->channel); + return -ENOMEM; + } + + mkcs = netdev_priv(ndev); + mkcs->netdev = ndev; + mkcs->client.dev = kcs_bmc; + mkcs->client.ops = &kcs_bmc_mctp_client_ops; + mkcs->data_in = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL); + if (!mkcs->data_in) { + dev_err_probe( + kcs_bmc->dev, -ENOMEM, + "failed to allocate data_in buffer for KCS channel %d\n", + kcs_bmc->channel); + rc = -ENOMEM; + goto free_netdev; + } + mkcs->data_out = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, GFP_KERNEL); + if (!mkcs->data_out) { + dev_err_probe( + kcs_bmc->dev, -ENOMEM, + "failed to allocate data_out buffer for KCS channel %d\n", + kcs_bmc->channel); + rc = -ENOMEM; + goto free_netdev; + } + + INIT_WORK(&mkcs->rx_work, mctp_kcs_rx_work); + + rc = register_netdev(ndev); + if (rc) + goto free_netdev; + + spin_lock_irq(&kcs_bmc_mctp_instances_lock); + list_add(&mkcs->entry, &kcs_bmc_mctp_instances); + spin_unlock_irq(&kcs_bmc_mctp_instances_lock); + + dev_info(kcs_bmc->dev, "Add MCTP client for the KCS channel %d", + kcs_bmc->channel); + return 0; + +free_netdev: + free_netdev(ndev); + + return rc; +} + +static int kcs_bmc_mctp_remove_device(struct kcs_bmc_device *kcs_bmc) +{ + struct mctp_kcs *mkcs = NULL, *pos; + + dev_info(kcs_bmc->dev, "Remove MCTP client for the KCS channel %d", + kcs_bmc->channel); + spin_lock_irq(&kcs_bmc_mctp_instances_lock); + list_for_each_entry(pos, &kcs_bmc_mctp_instances, entry) { + if (pos->client.dev == kcs_bmc) { + mkcs = pos; + list_del(&pos->entry); + break; + } + } + spin_unlock_irq(&kcs_bmc_mctp_instances_lock); + + if (!mkcs) + return -ENODEV; + + unregister_netdev(mkcs->netdev); + free_netdev(mkcs->netdev); + kcs_bmc_disable_device(kcs_bmc, &mkcs->client); + devm_kfree(kcs_bmc->dev, mkcs->data_out); + devm_kfree(kcs_bmc->dev, mkcs->data_in); + return 0; +} + +static const struct kcs_bmc_driver_ops kcs_bmc_mctp_driver_ops = { + .add_device = kcs_bmc_mctp_add_device, + .remove_device = kcs_bmc_mctp_remove_device, +}; + +static struct kcs_bmc_driver kcs_bmc_mctp_driver = { + .ops = &kcs_bmc_mctp_driver_ops, +}; + +static int __init mctp_kcs_init(void) +{ + kcs_bmc_register_driver(&kcs_bmc_mctp_driver); + return 0; +} + +static void __exit mctp_kcs_exit(void) +{ + kcs_bmc_unregister_driver(&kcs_bmc_mctp_driver); +} + +module_init(mctp_kcs_init); +module_exit(mctp_kcs_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Konstantin Aladyshev <aladyshev22@gmail.com>"); +MODULE_DESCRIPTION("MCTP KCS transport");

[v5,3/3] mctp: Add MCTP-over-KCS transport binding

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