static int tb_switch_add_dma_port()

in switch.c [2413:2505]

• 56 lines of code
• 19 McCabe index (conditional complexity)

static int tb_switch_add_dma_port(struct tb_switch *sw)
{
	u32 status;
	int ret;

	switch (sw->generation) {
	case 2:
		/* Only root switch can be upgraded */
		if (tb_route(sw))
			return 0;

		fallthrough;
	case 3:
	case 4:
		ret = tb_switch_set_uuid(sw);
		if (ret)
			return ret;
		break;

	default:
		/*
		 * DMA port is the only thing available when the switch
		 * is in safe mode.
		 */
		if (!sw->safe_mode)
			return 0;
		break;
	}

	if (sw->no_nvm_upgrade)
		return 0;

	if (tb_switch_is_usb4(sw)) {
		ret = usb4_switch_nvm_authenticate_status(sw, &status);
		if (ret)
			return ret;

		if (status) {
			tb_sw_info(sw, "switch flash authentication failed\n");
			nvm_set_auth_status(sw, status);
		}

		return 0;
	}

	/* Root switch DMA port requires running firmware */
	if (!tb_route(sw) && !tb_switch_is_icm(sw))
		return 0;

	sw->dma_port = dma_port_alloc(sw);
	if (!sw->dma_port)
		return 0;

	/*
	 * If there is status already set then authentication failed
	 * when the dma_port_flash_update_auth() returned. Power cycling
	 * is not needed (it was done already) so only thing we do here
	 * is to unblock runtime PM of the root port.
	 */
	nvm_get_auth_status(sw, &status);
	if (status) {
		if (!tb_route(sw))
			nvm_authenticate_complete_dma_port(sw);
		return 0;
	}

	/*
	 * Check status of the previous flash authentication. If there
	 * is one we need to power cycle the switch in any case to make
	 * it functional again.
	 */
	ret = dma_port_flash_update_auth_status(sw->dma_port, &status);
	if (ret <= 0)
		return ret;

	/* Now we can allow root port to suspend again */
	if (!tb_route(sw))
		nvm_authenticate_complete_dma_port(sw);

	if (status) {
		tb_sw_info(sw, "switch flash authentication failed\n");
		nvm_set_auth_status(sw, status);
	}

	tb_sw_info(sw, "power cycling the switch now\n");
	dma_port_power_cycle(sw->dma_port);

	/*
	 * We return error here which causes the switch adding failure.
	 * It should appear back after power cycle is complete.
	 */
	return -ESHUTDOWN;
}