// SPDX-License-Identifier: GPL-2.0 /* * Management Controller Transport Protocol (MCTP) * Implements DMTF specification * "DSP0237 Management Component Transport Protocol (MCTP) SMBus/I2C * Transport Binding" * https://www.dmtf.org/sites/default/files/standards/documents/DSP0237_1.2.0.pdf * * A netdev is created for each I2C bus that handles MCTP. In the case of an I2C * mux topology a single I2C client is attached to the root of the mux topology, * shared between all mux I2C busses underneath. For non-mux cases an I2C client * is attached per netdev. * * mctp-i2c-controller.yml devicetree binding has further details. * * Copyright (c) 2022 Code Construct * Copyright (c) 2022 Google */ #include <linux/module.h> #include <linux/netdevice.h> #include <linux/i2c.h> #include <linux/i2c-mux.h> #include <linux/if_arp.h> #include <net/mctp.h> #include <net/mctpdevice.h> /* byte_count is limited to u8 */ #define MCTP_I2C_MAXBLOCK … /* One byte is taken by source_slave */ #define MCTP_I2C_MAXMTU … #define MCTP_I2C_MINMTU … /* Allow space for dest_address, command, byte_count, data, PEC */ #define MCTP_I2C_BUFSZ … #define MCTP_I2C_MINLEN … #define MCTP_I2C_COMMANDCODE … #define MCTP_I2C_TX_WORK_LEN … /* Sufficient for 64kB at min mtu */ #define MCTP_I2C_TX_QUEUE_LEN … #define MCTP_I2C_OF_PROP … enum { … }; /* List of all struct mctp_i2c_client * Lock protects driver_clients and also prevents adding/removing adapters * during mctp_i2c_client probe/remove. */ static DEFINE_MUTEX(driver_clients_lock); static LIST_HEAD(driver_clients); struct mctp_i2c_client; /* The netdev structure. One of these per I2C adapter. */ struct mctp_i2c_dev { … }; /* The i2c client structure. One per hardware i2c bus at the top of the * mux tree, shared by multiple netdevs */ struct mctp_i2c_client { … }; /* Header on the wire. */ struct mctp_i2c_hdr { … }; static int mctp_i2c_recv(struct mctp_i2c_dev *midev); static int mctp_i2c_slave_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val); static void mctp_i2c_ndo_uninit(struct net_device *dev); static int mctp_i2c_ndo_open(struct net_device *dev); static struct i2c_adapter *mux_root_adapter(struct i2c_adapter *adap) { … } /* Creates a new i2c slave device attached to the root adapter. * Sets up the slave callback. * Must be called with a client on a root adapter. */ static struct mctp_i2c_client *mctp_i2c_new_client(struct i2c_client *client) { … } static void mctp_i2c_free_client(struct mctp_i2c_client *mcli) { … } /* Switch the mctp i2c device to receive responses. * Call with sel_lock held */ static void __mctp_i2c_device_select(struct mctp_i2c_client *mcli, struct mctp_i2c_dev *midev) { … } /* Switch the mctp i2c device to receive responses */ static void mctp_i2c_device_select(struct mctp_i2c_client *mcli, struct mctp_i2c_dev *midev) { … } static int mctp_i2c_slave_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val) { … } /* Processes incoming data that has been accumulated by the slave cb */ static int mctp_i2c_recv(struct mctp_i2c_dev *midev) { … } enum mctp_i2c_flow_state { … }; static enum mctp_i2c_flow_state mctp_i2c_get_tx_flow_state(struct mctp_i2c_dev *midev, struct sk_buff *skb) { … } /* We're not contending with ourselves here; we only need to exclude other * i2c clients from using the bus. refcounts are simply to prevent * recursive locking. */ static void mctp_i2c_lock_nest(struct mctp_i2c_dev *midev) { … } static void mctp_i2c_unlock_nest(struct mctp_i2c_dev *midev) { … } /* Unlocks the bus if was previously locked, used for cleanup */ static void mctp_i2c_unlock_reset(struct mctp_i2c_dev *midev) { … } static void mctp_i2c_invalidate_tx_flow(struct mctp_i2c_dev *midev, struct sk_buff *skb) { … } static void mctp_i2c_xmit(struct mctp_i2c_dev *midev, struct sk_buff *skb) { … } static void mctp_i2c_flow_release(struct mctp_i2c_dev *midev) { … } static int mctp_i2c_header_create(struct sk_buff *skb, struct net_device *dev, unsigned short type, const void *daddr, const void *saddr, unsigned int len) { … } static int mctp_i2c_tx_thread(void *data) { … } static netdev_tx_t mctp_i2c_start_xmit(struct sk_buff *skb, struct net_device *dev) { … } static void mctp_i2c_release_flow(struct mctp_dev *mdev, struct mctp_sk_key *key) { … } static const struct net_device_ops mctp_i2c_ops = …; static const struct header_ops mctp_i2c_headops = …; static const struct mctp_netdev_ops mctp_i2c_mctp_ops = …; static void mctp_i2c_net_setup(struct net_device *dev) { … } /* Populates the mctp_i2c_dev priv struct for a netdev. * Returns an error pointer on failure. */ static struct mctp_i2c_dev *mctp_i2c_midev_init(struct net_device *dev, struct mctp_i2c_client *mcli, struct i2c_adapter *adap) { … } /* Counterpart of mctp_i2c_midev_init */ static void mctp_i2c_midev_free(struct mctp_i2c_dev *midev) { … } /* Stops, unregisters, and frees midev */ static void mctp_i2c_unregister(struct mctp_i2c_dev *midev) { … } static void mctp_i2c_ndo_uninit(struct net_device *dev) { … } static int mctp_i2c_ndo_open(struct net_device *dev) { … } static int mctp_i2c_add_netdev(struct mctp_i2c_client *mcli, struct i2c_adapter *adap) { … } /* Removes any netdev for adap. mcli is the parent root i2c client */ static void mctp_i2c_remove_netdev(struct mctp_i2c_client *mcli, struct i2c_adapter *adap) { … } /* Determines whether a device is an i2c adapter. * Optionally returns the root i2c_adapter */ static struct i2c_adapter *mctp_i2c_get_adapter(struct device *dev, struct i2c_adapter **ret_root) { … } /* Determines whether a device is an i2c adapter with the "mctp-controller" * devicetree property set. If adap is not an OF node, returns match_no_of */ static bool mctp_i2c_adapter_match(struct i2c_adapter *adap, bool match_no_of) { … } /* Called for each existing i2c device (adapter or client) when a * new mctp-i2c client is probed. */ static int mctp_i2c_client_try_attach(struct device *dev, void *data) { … } static void mctp_i2c_notify_add(struct device *dev) { … } static void mctp_i2c_notify_del(struct device *dev) { … } static int mctp_i2c_probe(struct i2c_client *client) { … } static void mctp_i2c_remove(struct i2c_client *client) { … } /* We look for a 'mctp-controller' property on I2C busses as they are * added/deleted, creating/removing netdevs as required. */ static int mctp_i2c_notifier_call(struct notifier_block *nb, unsigned long action, void *data) { … } static struct notifier_block mctp_i2c_notifier = …; static const struct i2c_device_id mctp_i2c_id[] = …; MODULE_DEVICE_TABLE(i2c, mctp_i2c_id); static const struct of_device_id mctp_i2c_of_match[] = …; MODULE_DEVICE_TABLE(of, mctp_i2c_of_match); static struct i2c_driver mctp_i2c_driver = …; static __init int mctp_i2c_mod_init(void) { … } static __exit void mctp_i2c_mod_exit(void) { … } module_init(…) …; module_exit(mctp_i2c_mod_exit); MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …; MODULE_AUTHOR(…) …;
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