blob: ba0c2d2c6bbe0b750f0babbb0773d918ea7d4221 [file] [log] [blame]
// 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 curr_seq;
u8 bmcaddr;
u32 retry_time_ms;
u32 max_retries;
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(iidev->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 <= iidev->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 device *dev = &client->dev;
struct ipmi_ipmb_dev *iidev;
int rv;
iidev = devm_kzalloc(&client->dev, sizeof(*iidev), GFP_KERNEL);
if (!iidev)
return -ENOMEM;
if (of_property_read_u8(dev->of_node, "bmcaddr", &iidev->bmcaddr) != 0)
iidev->bmcaddr = bmcaddr;
if (iidev->bmcaddr == 0 || iidev->bmcaddr & 1) {
/* Can't have the write bit set. */
dev_notice(&client->dev,
"Invalid bmc address value %2.2x\n", iidev->bmcaddr);
return -EINVAL;
}
if (of_property_read_u32(dev->of_node, "retry-time",
&iidev->retry_time_ms) != 0)
iidev->retry_time_ms = retry_time_ms;
if (of_property_read_u32(dev->of_node, "max-retries",
&iidev->max_retries) != 0)
iidev->max_retries = max_retries;
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;
}
#ifdef CONFIG_OF
static const struct of_device_id of_ipmi_ipmb_match[] = {
{ .type = "ipmi", .compatible = DEVICE_NAME },
{},
};
MODULE_DEVICE_TABLE(of, of_ipmi_ipmb_match);
#else
#define of_ipmi_ipmb_match NULL
#endif
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,
.of_match_table = of_ipmi_ipmb_match,
},
.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");