--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Driver to talk to a remote management controller on IPMB.
+ */
+
+#include <linux/acpi.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/semaphore.h>
+#include <linux/kthread.h>
+#include <linux/wait.h>
+#include <linux/ipmi_msgdefs.h>
+#include <linux/ipmi_smi.h>
+
+#define DEVICE_NAME "ipmi-ipmb"
+
+static int bmcaddr = 0x20;
+module_param(bmcaddr, int, 0644);
+MODULE_PARM_DESC(bmcaddr, "Address to use for BMC.");
+
+static unsigned int retry_time_ms = 250;
+module_param(retry_time_ms, uint, 0644);
+MODULE_PARM_DESC(max_retries, "Timeout time between retries, in milliseconds.");
+
+static unsigned int max_retries = 1;
+module_param(max_retries, uint, 0644);
+MODULE_PARM_DESC(max_retries, "Max resends of a command before timing out.");
+
+/* Add room for the two slave addresses, two checksums, and rqSeq. */
+#define IPMB_MAX_MSG_LEN (IPMI_MAX_MSG_LENGTH + 5)
+
+struct ipmi_ipmb_dev {
+ struct ipmi_smi *intf;
+ struct i2c_client *client;
+
+ struct ipmi_smi_handlers handlers;
+
+ bool ready;
+
+ u8 bmcaddr;
+
+ u8 curr_seq;
+
+ struct ipmi_smi_msg *next_msg;
+ struct ipmi_smi_msg *working_msg;
+
+ /* Transmit thread. */
+ struct task_struct *thread;
+ struct semaphore wake_thread;
+ struct semaphore got_rsp;
+ spinlock_t lock;
+ bool stopping;
+
+ u8 xmitmsg[IPMB_MAX_MSG_LEN];
+ unsigned int xmitlen;
+
+ u8 rcvmsg[IPMB_MAX_MSG_LEN];
+ unsigned int rcvlen;
+ bool overrun;
+};
+
+static bool valid_ipmb(struct ipmi_ipmb_dev *iidev)
+{
+ u8 *msg = iidev->rcvmsg;
+ u8 netfn;
+
+ if (iidev->overrun)
+ return false;
+
+ /* Minimum message size. */
+ if (iidev->rcvlen < 7)
+ return false;
+
+ /* Is it a response? */
+ netfn = msg[1] >> 2;
+ if (netfn & 1) {
+ /* Response messages have an added completion code. */
+ if (iidev->rcvlen < 8)
+ return false;
+ }
+
+ if (ipmb_checksum(msg, 3) != 0)
+ return false;
+ if (ipmb_checksum(msg + 3, iidev->rcvlen - 3) != 0)
+ return false;
+
+ return true;
+}
+
+static void ipmi_ipmb_check_msg_done(struct ipmi_ipmb_dev *iidev)
+{
+ struct ipmi_smi_msg *imsg = NULL;
+ u8 *msg = iidev->rcvmsg;
+ bool is_cmd;
+ unsigned long flags;
+
+ if (iidev->rcvlen == 0)
+ return;
+ if (!valid_ipmb(iidev))
+ goto done;
+
+ is_cmd = ((msg[1] >> 2) & 1) == 0;
+
+ if (is_cmd) {
+ /* Ignore commands until we are up. */
+ if (!iidev->ready)
+ goto done;
+
+ /* It's a command, allocate a message for it. */
+ imsg = ipmi_alloc_smi_msg();
+ if (!imsg)
+ goto done;
+ imsg->type = IPMI_SMI_MSG_TYPE_IPMB_DIRECT;
+ imsg->data_size = 0;
+ } else {
+ spin_lock_irqsave(&iidev->lock, flags);
+ if (iidev->working_msg) {
+ u8 seq = msg[4] >> 2;
+ bool xmit_rsp = (iidev->working_msg->data[0] >> 2) & 1;
+
+ /*
+ * Responses should carry the sequence we sent
+ * them with. If it's a transmitted response,
+ * ignore it. And if the message hasn't been
+ * transmitted, ignore it.
+ */
+ if (!xmit_rsp && seq == iidev->curr_seq) {
+ iidev->curr_seq = (iidev->curr_seq + 1) & 0x3f;
+
+ imsg = iidev->working_msg;
+ iidev->working_msg = NULL;
+ }
+ }
+ spin_unlock_irqrestore(&iidev->lock, flags);
+ }
+
+ if (!imsg)
+ goto done;
+
+ if (imsg->type == IPMI_SMI_MSG_TYPE_IPMB_DIRECT) {
+ imsg->rsp[0] = msg[1]; /* NetFn/LUN */
+ /*
+ * Keep the source address, rqSeq. Drop the trailing
+ * checksum.
+ */
+ memcpy(imsg->rsp + 1, msg + 3, iidev->rcvlen - 4);
+ imsg->rsp_size = iidev->rcvlen - 3;
+ } else {
+ imsg->rsp[0] = msg[1]; /* NetFn/LUN */
+ /*
+ * Skip the source address, rqSeq. Drop the trailing
+ * checksum.
+ */
+ memcpy(imsg->rsp + 1, msg + 5, iidev->rcvlen - 6);
+ imsg->rsp_size = iidev->rcvlen - 5;
+ }
+ ipmi_smi_msg_received(iidev->intf, imsg);
+ if (!is_cmd)
+ up(&iidev->got_rsp);
+
+done:
+ iidev->overrun = false;
+ iidev->rcvlen = 0;
+}
+
+/*
+ * The IPMB protocol only supports i2c writes so there is no need to
+ * support I2C_SLAVE_READ* events, except to know if the other end has
+ * issued a read without going to stop mode.
+ */
+static int ipmi_ipmb_slave_cb(struct i2c_client *client,
+ enum i2c_slave_event event, u8 *val)
+{
+ struct ipmi_ipmb_dev *iidev = i2c_get_clientdata(client);
+
+ switch (event) {
+ case I2C_SLAVE_WRITE_REQUESTED:
+ ipmi_ipmb_check_msg_done(iidev);
+ /*
+ * First byte is the slave address, to ease the checksum
+ * calculation.
+ */
+ iidev->rcvmsg[0] = client->addr << 1;
+ iidev->rcvlen = 1;
+ break;
+
+ case I2C_SLAVE_WRITE_RECEIVED:
+ if (iidev->rcvlen > sizeof(iidev->rcvmsg))
+ iidev->overrun = true;
+ else
+ iidev->rcvmsg[iidev->rcvlen++] = *val;
+ break;
+
+ case I2C_SLAVE_READ_REQUESTED:
+ case I2C_SLAVE_STOP:
+ ipmi_ipmb_check_msg_done(iidev);
+ break;
+
+ case I2C_SLAVE_READ_PROCESSED:
+ break;
+ }
+
+ return 0;
+}
+
+static void ipmi_ipmb_send_response(struct ipmi_ipmb_dev *iidev,
+ struct ipmi_smi_msg *msg, u8 cc)
+{
+ if ((msg->data[0] >> 2) & 1) {
+ /*
+ * It's a response being sent, we needto return a
+ * response response. Fake a send msg command
+ * response with channel 0. This will always be ipmb
+ * direct.
+ */
+ msg->data[0] = (IPMI_NETFN_APP_REQUEST | 1) << 2;
+ msg->data[3] = IPMI_SEND_MSG_CMD;
+ msg->data[4] = cc;
+ msg->data_size = 5;
+ }
+ msg->rsp[0] = msg->data[0] | (1 << 2);
+ if (msg->type == IPMI_SMI_MSG_TYPE_IPMB_DIRECT) {
+ msg->rsp[1] = msg->data[1];
+ msg->rsp[2] = msg->data[2];
+ msg->rsp[3] = msg->data[3];
+ msg->rsp[4] = cc;
+ msg->rsp_size = 5;
+ } else {
+ msg->rsp[1] = msg->data[1];
+ msg->rsp[2] = cc;
+ msg->rsp_size = 3;
+ }
+ ipmi_smi_msg_received(iidev->intf, msg);
+}
+
+static void ipmi_ipmb_format_for_xmit(struct ipmi_ipmb_dev *iidev,
+ struct ipmi_smi_msg *msg)
+{
+ if (msg->type == IPMI_SMI_MSG_TYPE_IPMB_DIRECT) {
+ iidev->xmitmsg[0] = msg->data[1];
+ iidev->xmitmsg[1] = msg->data[0];
+ memcpy(iidev->xmitmsg + 4, msg->data + 2, msg->data_size - 2);
+ iidev->xmitlen = msg->data_size + 2;
+ } else {
+ iidev->xmitmsg[0] = iidev->bmcaddr;
+ iidev->xmitmsg[1] = msg->data[0];
+ iidev->xmitmsg[4] = 0;
+ memcpy(iidev->xmitmsg + 5, msg->data + 1, msg->data_size - 1);
+ iidev->xmitlen = msg->data_size + 4;
+ }
+ iidev->xmitmsg[3] = iidev->client->addr << 1;
+ if (((msg->data[0] >> 2) & 1) == 0)
+ /* If it's a command, put in our own sequence number. */
+ iidev->xmitmsg[4] = ((iidev->xmitmsg[4] & 0x03) |
+ (iidev->curr_seq << 2));
+
+ /* Now add on the final checksums. */
+ iidev->xmitmsg[2] = ipmb_checksum(iidev->xmitmsg, 2);
+ iidev->xmitmsg[iidev->xmitlen] =
+ ipmb_checksum(iidev->xmitmsg + 3, iidev->xmitlen - 3);
+ iidev->xmitlen++;
+}
+
+static int ipmi_ipmb_thread(void *data)
+{
+ struct ipmi_ipmb_dev *iidev = data;
+
+ while (!kthread_should_stop()) {
+ long ret;
+ struct i2c_msg i2c_msg;
+ struct ipmi_smi_msg *msg = NULL;
+ unsigned long flags;
+ unsigned int retries = 0;
+
+ /* Wait for a message to send */
+ ret = down_interruptible(&iidev->wake_thread);
+ if (iidev->stopping)
+ break;
+ if (ret)
+ continue;
+
+ spin_lock_irqsave(&iidev->lock, flags);
+ if (iidev->next_msg) {
+ msg = iidev->next_msg;
+ iidev->next_msg = NULL;
+ }
+ spin_unlock_irqrestore(&iidev->lock, flags);
+ if (!msg)
+ continue;
+
+ ipmi_ipmb_format_for_xmit(iidev, msg);
+
+retry:
+ i2c_msg.len = iidev->xmitlen - 1;
+ if (i2c_msg.len > 32) {
+ ipmi_ipmb_send_response(iidev, msg,
+ IPMI_REQ_LEN_EXCEEDED_ERR);
+ continue;
+ }
+
+ i2c_msg.addr = iidev->xmitmsg[0] >> 1;
+ i2c_msg.flags = 0;
+ i2c_msg.buf = iidev->xmitmsg + 1;
+
+ /* Rely on i2c_transfer for a barrier. */
+ iidev->working_msg = msg;
+
+ ret = i2c_transfer(iidev->client->adapter, &i2c_msg, 1);
+
+ if ((msg->data[0] >> 2) & 1) {
+ /*
+ * It's a response, nothing will be returned
+ * by the other end.
+ */
+
+ iidev->working_msg = NULL;
+ ipmi_ipmb_send_response(iidev, msg,
+ ret < 0 ? IPMI_BUS_ERR : 0);
+ continue;
+ }
+ if (ret < 0) {
+ iidev->working_msg = NULL;
+ ipmi_ipmb_send_response(iidev, msg, IPMI_BUS_ERR);
+ continue;
+ }
+
+ /* A command was sent, wait for its response. */
+ ret = down_timeout(&iidev->got_rsp,
+ msecs_to_jiffies(retry_time_ms));
+
+ /*
+ * Grab the message if we can. If the handler hasn't
+ * already handled it, the message will still be there.
+ */
+ spin_lock_irqsave(&iidev->lock, flags);
+ msg = iidev->working_msg;
+ iidev->working_msg = NULL;
+ spin_unlock_irqrestore(&iidev->lock, flags);
+
+ if (!msg && ret) {
+ /*
+ * If working_msg is not set and we timed out,
+ * that means the message grabbed by
+ * check_msg_done before we could grab it
+ * here. Wait again for check_msg_done to up
+ * the semaphore.
+ */
+ down(&iidev->got_rsp);
+ } else if (msg && ++retries <= max_retries) {
+ spin_lock_irqsave(&iidev->lock, flags);
+ iidev->working_msg = msg;
+ spin_unlock_irqrestore(&iidev->lock, flags);
+ goto retry;
+ }
+
+ if (msg)
+ ipmi_ipmb_send_response(iidev, msg, IPMI_TIMEOUT_ERR);
+ }
+
+ if (iidev->next_msg)
+ /* Return an unspecified error. */
+ ipmi_ipmb_send_response(iidev, iidev->next_msg, 0xff);
+
+ return 0;
+}
+
+static int ipmi_ipmb_start_processing(void *send_info,
+ struct ipmi_smi *new_intf)
+{
+ struct ipmi_ipmb_dev *iidev = send_info;
+
+ iidev->intf = new_intf;
+ iidev->ready = true;
+ return 0;
+}
+
+static void ipmi_ipmb_stop_thread(struct ipmi_ipmb_dev *iidev)
+{
+ if (iidev->thread) {
+ struct task_struct *t = iidev->thread;
+
+ iidev->thread = NULL;
+ iidev->stopping = true;
+ up(&iidev->wake_thread);
+ up(&iidev->got_rsp);
+ kthread_stop(t);
+ }
+}
+
+static void ipmi_ipmb_shutdown(void *send_info)
+{
+ struct ipmi_ipmb_dev *iidev = send_info;
+
+ ipmi_ipmb_stop_thread(iidev);
+}
+
+static void ipmi_ipmb_sender(void *send_info,
+ struct ipmi_smi_msg *msg)
+{
+ struct ipmi_ipmb_dev *iidev = send_info;
+ unsigned long flags;
+
+ spin_lock_irqsave(&iidev->lock, flags);
+ BUG_ON(iidev->next_msg);
+
+ iidev->next_msg = msg;
+ spin_unlock_irqrestore(&iidev->lock, flags);
+
+ up(&iidev->wake_thread);
+}
+
+static void ipmi_ipmb_request_events(void *send_info)
+{
+ /* We don't fetch events here. */
+}
+
+static int ipmi_ipmb_remove(struct i2c_client *client)
+{
+ struct ipmi_ipmb_dev *iidev = i2c_get_clientdata(client);
+
+ if (iidev->client) {
+ iidev->client = NULL;
+ i2c_slave_unregister(client);
+ }
+ ipmi_ipmb_stop_thread(iidev);
+
+ return 0;
+}
+
+static int ipmi_ipmb_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct ipmi_ipmb_dev *iidev;
+ int rv;
+
+ iidev = devm_kzalloc(&client->dev, sizeof(*iidev), GFP_KERNEL);
+ if (!iidev)
+ return -ENOMEM;
+
+ iidev->bmcaddr = bmcaddr;
+
+ i2c_set_clientdata(client, iidev);
+ client->flags |= I2C_CLIENT_SLAVE;
+
+ rv = i2c_slave_register(client, ipmi_ipmb_slave_cb);
+ if (rv)
+ return rv;
+
+ iidev->client = client;
+
+ iidev->handlers.flags = IPMI_SMI_CAN_HANDLE_IPMB_DIRECT;
+ iidev->handlers.start_processing = ipmi_ipmb_start_processing;
+ iidev->handlers.shutdown = ipmi_ipmb_shutdown;
+ iidev->handlers.sender = ipmi_ipmb_sender;
+ iidev->handlers.request_events = ipmi_ipmb_request_events;
+
+ spin_lock_init(&iidev->lock);
+ sema_init(&iidev->wake_thread, 0);
+ sema_init(&iidev->got_rsp, 0);
+
+ iidev->thread = kthread_run(ipmi_ipmb_thread, iidev,
+ "kipmb%4.4x", client->addr);
+ if (IS_ERR(iidev->thread)) {
+ rv = PTR_ERR(iidev->thread);
+ dev_notice(&client->dev,
+ "Could not start kernel thread: error %d\n", rv);
+ goto out_err;
+ }
+
+ rv = ipmi_register_smi(&iidev->handlers,
+ iidev,
+ &client->dev,
+ iidev->bmcaddr);
+ if (rv)
+ goto out_err;
+
+ return 0;
+
+out_err:
+ ipmi_ipmb_remove(client);
+ return rv;
+}
+
+static const struct i2c_device_id ipmi_ipmb_id[] = {
+ { DEVICE_NAME, 0 },
+ {},
+};
+MODULE_DEVICE_TABLE(i2c, ipmi_ipmb_id);
+
+static struct i2c_driver ipmi_ipmb_driver = {
+ .class = I2C_CLASS_HWMON,
+ .driver = {
+ .name = DEVICE_NAME,
+ },
+ .probe = ipmi_ipmb_probe,
+ .remove = ipmi_ipmb_remove,
+ .id_table = ipmi_ipmb_id,
+};
+module_i2c_driver(ipmi_ipmb_driver);
+
+MODULE_AUTHOR("Corey Minyard");
+MODULE_DESCRIPTION("IPMI IPMB driver");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-starfive.git / commitdiff