static int xgene_hwmon_probe()

in xgene-hwmon.c [615:758]

• 110 lines of code
• 14 McCabe index (conditional complexity)

static int xgene_hwmon_probe(struct platform_device *pdev)
{
	struct xgene_hwmon_dev *ctx;
	struct mbox_client *cl;
	int rc;

	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
	if (!ctx)
		return -ENOMEM;

	ctx->dev = &pdev->dev;
	platform_set_drvdata(pdev, ctx);
	cl = &ctx->mbox_client;

	spin_lock_init(&ctx->kfifo_lock);
	mutex_init(&ctx->rd_mutex);

	rc = kfifo_alloc(&ctx->async_msg_fifo,
			 sizeof(struct slimpro_resp_msg) * ASYNC_MSG_FIFO_SIZE,
			 GFP_KERNEL);
	if (rc)
		return -ENOMEM;

	INIT_WORK(&ctx->workq, xgene_hwmon_evt_work);

	/* Request mailbox channel */
	cl->dev = &pdev->dev;
	cl->tx_done = xgene_hwmon_tx_done;
	cl->tx_block = false;
	cl->tx_tout = MBOX_OP_TIMEOUTMS;
	cl->knows_txdone = false;
	if (acpi_disabled) {
		cl->rx_callback = xgene_hwmon_rx_cb;
		ctx->mbox_chan = mbox_request_channel(cl, 0);
		if (IS_ERR(ctx->mbox_chan)) {
			dev_err(&pdev->dev,
				"SLIMpro mailbox channel request failed\n");
			rc = -ENODEV;
			goto out_mbox_free;
		}
	} else {
		struct pcc_mbox_chan *pcc_chan;
		const struct acpi_device_id *acpi_id;
		int version;

		acpi_id = acpi_match_device(pdev->dev.driver->acpi_match_table,
					    &pdev->dev);
		if (!acpi_id) {
			rc = -EINVAL;
			goto out_mbox_free;
		}

		version = (int)acpi_id->driver_data;

		if (device_property_read_u32(&pdev->dev, "pcc-channel",
					     &ctx->mbox_idx)) {
			dev_err(&pdev->dev, "no pcc-channel property\n");
			rc = -ENODEV;
			goto out_mbox_free;
		}

		cl->rx_callback = xgene_hwmon_pcc_rx_cb;
		pcc_chan = pcc_mbox_request_channel(cl, ctx->mbox_idx);
		if (IS_ERR(pcc_chan)) {
			dev_err(&pdev->dev,
				"PPC channel request failed\n");
			rc = -ENODEV;
			goto out_mbox_free;
		}

		ctx->pcc_chan = pcc_chan;
		ctx->mbox_chan = pcc_chan->mchan;

		if (!ctx->mbox_chan->mbox->txdone_irq) {
			dev_err(&pdev->dev, "PCC IRQ not supported\n");
			rc = -ENODEV;
			goto out;
		}

		/*
		 * This is the shared communication region
		 * for the OS and Platform to communicate over.
		 */
		ctx->comm_base_addr = pcc_chan->shmem_base_addr;
		if (ctx->comm_base_addr) {
			if (version == XGENE_HWMON_V2)
				ctx->pcc_comm_addr = (void __force *)ioremap(
							ctx->comm_base_addr,
							pcc_chan->shmem_size);
			else
				ctx->pcc_comm_addr = memremap(
							ctx->comm_base_addr,
							pcc_chan->shmem_size,
							MEMREMAP_WB);
		} else {
			dev_err(&pdev->dev, "Failed to get PCC comm region\n");
			rc = -ENODEV;
			goto out;
		}

		if (!ctx->pcc_comm_addr) {
			dev_err(&pdev->dev,
				"Failed to ioremap PCC comm region\n");
			rc = -ENOMEM;
			goto out;
		}

		/*
		 * 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.
		 */
		ctx->usecs_lat = PCC_NUM_RETRIES * pcc_chan->latency;
	}

	ctx->hwmon_dev = hwmon_device_register_with_groups(ctx->dev,
							   "apm_xgene",
							   ctx,
							   xgene_hwmon_groups);
	if (IS_ERR(ctx->hwmon_dev)) {
		dev_err(&pdev->dev, "Failed to register HW monitor device\n");
		rc = PTR_ERR(ctx->hwmon_dev);
		goto out;
	}

	/*
	 * Schedule the bottom handler if there is a pending message.
	 */
	schedule_work(&ctx->workq);

	dev_info(&pdev->dev, "APM X-Gene SoC HW monitor driver registered\n");

	return 0;

out:
	if (acpi_disabled)
		mbox_free_channel(ctx->mbox_chan);
	else
		pcc_mbox_free_channel(ctx->pcc_chan);
out_mbox_free:
	kfifo_free(&ctx->async_msg_fifo);

	return rc;
}