mei: vsc: Improve error logging in vsc_identify_silicon()

vsc_identify_silicon() returns -EINVAL in various places without logging
what is going on.

And there are several bug reports about mei_vsc_hw_reset() failing with
-EINVAL before the "silicon stepping version is %u:%u" message get logged,
indicating this is coming from vsc_identify_silicon():

[   10.949657] intel_vsc intel_vsc: hw_reset failed ret = -22
[   10.988899] intel_vsc intel_vsc: hw_reset failed ret = -22
[   11.027140] intel_vsc intel_vsc: hw_reset failed ret = -22
[   11.027151] intel_vsc intel_vsc: reset: reached maximal consecutive resets: disabling the device
[   11.027155] intel_vsc intel_vsc: reset failed ret = -19
[   11.027157] intel_vsc intel_vsc: link layer initialization failed.
[   11.027159] intel_vsc intel_vsc: error -ENODEV: init hw failed

Add proper error logging to mei_vsc_hw_reset() so that it will be clear
why it is failing when it fails.

Link: intel/ivsc-driver#51
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20241108151234.36884-1-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: jwrdegoede

drivers/misc/mei/vsc-fw-loader.c

@@ -317,28 +317,34 @@ static int vsc_identify_silicon(struct vsc_fw_loader *fw_loader)
 	cmd->data.dump_mem.addr = cpu_to_le32(VSC_EFUSE_ADDR);
 	cmd->data.dump_mem.len = cpu_to_le16(sizeof(__le32));
 	ret = vsc_tp_rom_xfer(fw_loader->tp, cmd, ack, VSC_ROM_PKG_SIZE);
-	if (ret)
-		return ret;
-	if (ack->token == VSC_TOKEN_ERROR)
-		return -EINVAL;
+	if (ret || ack->token == VSC_TOKEN_ERROR) {
+		dev_err(fw_loader->dev, "CMD_DUMP_MEM error %d token %d\n", ret, ack->token);
+		return ret ?: -EINVAL;
+	}
 
 	cmd->magic = cpu_to_le32(VSC_MAGIC_NUM);
 	cmd->cmd_id = VSC_CMD_GET_CONT;
 	ret = vsc_tp_rom_xfer(fw_loader->tp, cmd, ack, VSC_ROM_PKG_SIZE);
-	if (ret)
-		return ret;
-	if (ack->token != VSC_TOKEN_DUMP_RESP)
-		return -EINVAL;
+	if (ret || ack->token != VSC_TOKEN_DUMP_RESP) {
+		dev_err(fw_loader->dev, "CMD_GETCONT error %d token %d\n", ret, ack->token);
+		return ret ?: -EINVAL;
+	}
 
 	version = FIELD_GET(VSC_MAINSTEPPING_VERSION_MASK, ack->payload[0]);
 	sub_version = FIELD_GET(VSC_SUBSTEPPING_VERSION_MASK, ack->payload[0]);
 
-	if (version != VSC_MAINSTEPPING_VERSION_A)
+	if (version != VSC_MAINSTEPPING_VERSION_A) {
+		dev_err(fw_loader->dev, "maintstepping mismatch expected %d got %d\n",
+			VSC_MAINSTEPPING_VERSION_A, version);
 		return -EINVAL;
+	}
 
 	if (sub_version != VSC_SUBSTEPPING_VERSION_0 &&
-	    sub_version != VSC_SUBSTEPPING_VERSION_1)
+	    sub_version != VSC_SUBSTEPPING_VERSION_1) {
+		dev_err(fw_loader->dev, "substepping %d is out of supported range %d - %d\n",
+			sub_version, VSC_SUBSTEPPING_VERSION_0, VSC_SUBSTEPPING_VERSION_1);
 		return -EINVAL;
+	}
 
 	dev_info(fw_loader->dev, "silicon stepping version is %u:%u\n",
 		 version, sub_version);