Merge tag 'for-linus-5.6-1' of https://github.com/cminyard/linux-ipmi

Pull IPMI update from Corey Minyard:
"Minor bug fixes for IPMI

I know this is late; I've been travelling and, well, I've been
distracted.

This is just a few bug fixes and adding i2c support to the IPMB
driver, which is something I wanted from the beginning for it"

* tag 'for-linus-5.6-1' of https://github.com/cminyard/linux-ipmi:
drivers: ipmi: fix off-by-one bounds check that leads to a out-of-bounds write
ipmi:ssif: Handle a possible NULL pointer reference
drivers: ipmi: Modify max length of IPMB packet
drivers: ipmi: Support raw i2c packet in IPMB

Documentation/driver-api/ipmb.rst

···
             ipmb@10 {
                     compatible = "ipmb-dev";
                     reg = <0x10>;
+                    i2c-protocol;
             };
      };
+
+If xmit of data to be done using raw i2c block vs smbus
+then "i2c-protocol" needs to be defined as above.
 
 2) Manually from Linux::
 

drivers/char/ipmi/ipmb_dev_int.c

···
 #include <linux/spinlock.h>
 #include <linux/wait.h>
 
-#define MAX_MSG_LEN		128
+#define MAX_MSG_LEN		240
 #define IPMB_REQUEST_LEN_MIN	7
 #define NETFN_RSP_BIT_MASK	0x4
 #define REQUEST_QUEUE_MAX_LEN	256
···
 	spinlock_t lock;
 	wait_queue_head_t wait_queue;
 	struct mutex file_mutex;
+	bool is_i2c_protocol;
 };
 
 static inline struct ipmb_dev *to_ipmb_dev(struct file *file)
···
 	return ret < 0 ? ret : count;
 }
 
+static int ipmb_i2c_write(struct i2c_client *client, u8 *msg, u8 addr)
+{
+	struct i2c_msg i2c_msg;
+
+	/*
+	 * subtract 1 byte (rq_sa) from the length of the msg passed to
+	 * raw i2c_transfer
+	 */
+	i2c_msg.len = msg[IPMB_MSG_LEN_IDX] - 1;
+
+	/* Assign message to buffer except first 2 bytes (length and address) */
+	i2c_msg.buf = msg + 2;
+
+	i2c_msg.addr = addr;
+	i2c_msg.flags = client->flags & I2C_CLIENT_PEC;
+
+	return i2c_transfer(client->adapter, &i2c_msg, 1);
+}
+
 static ssize_t ipmb_write(struct file *file, const char __user *buf,
 			size_t count, loff_t *ppos)
 {
···
 
 	rq_sa = GET_7BIT_ADDR(msg[RQ_SA_8BIT_IDX]);
 	netf_rq_lun = msg[NETFN_LUN_IDX];
+
+	/* Check i2c block transfer vs smbus */
+	if (ipmb_dev->is_i2c_protocol) {
+		ret = ipmb_i2c_write(ipmb_dev->client, msg, rq_sa);
+		return (ret == 1) ? count : ret;
+	}
 
 	/*
 	 * subtract rq_sa and netf_rq_lun from the length of the msg passed to
···
 		break;
 
 	case I2C_SLAVE_WRITE_RECEIVED:
-		if (ipmb_dev->msg_idx >= sizeof(struct ipmb_msg))
+		if (ipmb_dev->msg_idx >= sizeof(struct ipmb_msg) - 1)
 			break;
 
 		buf[++ipmb_dev->msg_idx] = *val;
···
 	ret = misc_register(&ipmb_dev->miscdev);
 	if (ret)
 		return ret;
+
+	ipmb_dev->is_i2c_protocol
+		= device_property_read_bool(&client->dev, "i2c-protocol");
 
 	ipmb_dev->client = client;
 	i2c_set_clientdata(client, ipmb_dev);

drivers/char/ipmi/ipmi_ssif.c

···
 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
 	msg = ssif_info->curr_msg;
 	if (msg) {
+		if (data) {
+			if (len > IPMI_MAX_MSG_LENGTH)
+				len = IPMI_MAX_MSG_LENGTH;
+			memcpy(msg->rsp, data, len);
+		} else {
+			len = 0;
+		}
 		msg->rsp_size = len;
-		if (msg->rsp_size > IPMI_MAX_MSG_LENGTH)
-			msg->rsp_size = IPMI_MAX_MSG_LENGTH;
-		memcpy(msg->rsp, data, msg->rsp_size);
 		ssif_info->curr_msg = NULL;
 	}