ipmi:ssif: Improve detecting during probing

If an IPMI SSIF device is probed and there is something there, but
probably not an actual BMC, the code would just issue a lot of errors
before it failed.  We kind of need these errors to help with certain
issues, and some of the failure reports are non-fatal.

However, a get device id command should alway work.  If that fails,
nothing else is going to work and it's a pretty good indication that
there's no valid BMC there.  So issue and check that command and bail
if it fails.

Reported-by: Ivan T. Ivanov <iivanov@suse.de>
Signed-off-by: Corey Minyard <corey@minyard.net>

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index e8e7b832c060a3735ee7dab87efdcd5a16dd2964..4c403e7a9fc84ef1a15b904749448ab23b5aa1dd 100644 (file)
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -1368,8 +1368,20 @@ static int ssif_detect(struct i2c_client *client, struct i2c_board_info *info)
        rv = do_cmd(client, 2, msg, &len, resp);
        if (rv)
                rv = -ENODEV;
-       else
+       else {
+           if (len < 3) {
+               rv = -ENODEV;
+           } else {
+               struct ipmi_device_id id;
+
+               rv = ipmi_demangle_device_id(resp[0] >> 2, resp[1],
+                                            resp + 2, len - 2, &id);
+               if (rv)
+                   rv = -ENODEV; /* Error means a BMC probably isn't there. */
+           }
+           if (!rv && info)
                strscpy(info->type, DEVICE_NAME, I2C_NAME_SIZE);
+       }
        kfree(resp);
        return rv;
 }
@@ -1704,6 +1716,16 @@ static int ssif_probe(struct i2c_client *client)
                ipmi_addr_src_to_str(ssif_info->addr_source),
                client->addr, client->adapter->name, slave_addr);
 
+       /*
+        * Send a get device id command and validate its response to
+        * make sure a valid BMC is there.
+        */
+       rv = ssif_detect(client, NULL);
+       if (rv) {
+               dev_err(&client->dev, "Not present\n");
+               goto out;
+       }
+
        /* Now check for system interface capabilities */
        msg[0] = IPMI_NETFN_APP_REQUEST << 2;
        msg[1] = IPMI_GET_SYSTEM_INTERFACE_CAPABILITIES_CMD;