ACPI: PCC: Setup PCC Opregion handler only if platform interrupt is available

Currently, PCC OpRegion handler depends on the availability of platform
interrupt to be functional currently. If it is not available, the OpRegion
can't be executed successfully or the desired outcome won't be possible.
So let's reject setting up the PCC OpRegion handler on the platform if
it doesn't support or have platform interrupt available.

Signed-off-by: Huisong Li <[e-mail]>
Reviewed-by: Sudeep Holla <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/acpi/acpi_pcc.c

···
 	struct pcc_data *data;
 	struct acpi_pcc_info *ctx = handler_context;
 	struct pcc_mbox_chan *pcc_chan;
+	static acpi_status ret;
 
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
···
 	if (IS_ERR(data->pcc_chan)) {
 		pr_err("Failed to find PCC channel for subspace %d\n",
 		       ctx->subspace_id);
-		kfree(data);
-		return AE_NOT_FOUND;
+		ret = AE_NOT_FOUND;
+		goto err_free_data;
 	}
 
 	pcc_chan = data->pcc_chan;
+	if (!pcc_chan->mchan->mbox->txdone_irq) {
+		pr_err("This channel-%d does not support interrupt.\n",
+		       ctx->subspace_id);
+		ret = AE_SUPPORT;
+		goto err_free_channel;
+	}
 	data->pcc_comm_addr = acpi_os_ioremap(pcc_chan->shmem_base_addr,
 					      pcc_chan->shmem_size);
 	if (!data->pcc_comm_addr) {
 		pr_err("Failed to ioremap PCC comm region mem for %d\n",
 		       ctx->subspace_id);
-		pcc_mbox_free_channel(data->pcc_chan);
-		kfree(data);
-		return AE_NO_MEMORY;
+		ret = AE_NO_MEMORY;
+		goto err_free_channel;
 	}
 
 	*region_context = data;
 	return AE_OK;
+
+err_free_channel:
+	pcc_mbox_free_channel(data->pcc_chan);
+err_free_data:
+	kfree(data);
+
+	return ret;
 }
 
 static acpi_status
···
 	if (ret < 0)
 		return AE_ERROR;
 
-	if (data->pcc_chan->mchan->mbox->txdone_irq) {
-		/*
-		 * pcc_chan->latency is just a Nominal value. In reality the remote
-		 * processor could be much slower to reply. So add an arbitrary
-		 * amount of wait on top of Nominal.
-		 */
-		usecs_lat = PCC_CMD_WAIT_RETRIES_NUM * data->pcc_chan->latency;
-		ret = wait_for_completion_timeout(&data->done,
-						  usecs_to_jiffies(usecs_lat));
-		if (ret == 0) {
-			pr_err("PCC command executed timeout!\n");
-			return AE_TIME;
-		}
+	/*
+	 * pcc_chan->latency is just a Nominal value. In reality the remote
+	 * processor could be much slower to reply. So add an arbitrary
+	 * amount of wait on top of Nominal.
+	 */
+	usecs_lat = PCC_CMD_WAIT_RETRIES_NUM * data->pcc_chan->latency;
+	ret = wait_for_completion_timeout(&data->done,
+						usecs_to_jiffies(usecs_lat));
+	if (ret == 0) {
+		pr_err("PCC command executed timeout!\n");
+		return AE_TIME;
 	}
 
 	mbox_chan_txdone(data->pcc_chan->mchan, ret);