static irqreturn_t interrupt_handler()

in nozomi.c [1108:1231]

• 108 lines of code
• 27 McCabe index (conditional complexity)

static irqreturn_t interrupt_handler(int irq, void *dev_id)
{
	struct nozomi *dc = dev_id;
	unsigned int a;
	u16 read_iir;

	if (!dc)
		return IRQ_NONE;

	spin_lock(&dc->spin_mutex);
	read_iir = readw(dc->reg_iir);

	/* Card removed */
	if (read_iir == (u16)-1)
		goto none;
	/*
	 * Just handle interrupt enabled in IER
	 * (by masking with dc->last_ier)
	 */
	read_iir &= dc->last_ier;

	if (read_iir == 0)
		goto none;


	DBG4("%s irq:0x%04X, prev:0x%04X", interrupt2str(read_iir), read_iir,
		dc->last_ier);

	if (read_iir & RESET) {
		if (unlikely(!nozomi_read_config_table(dc))) {
			dc->last_ier = 0x0;
			writew(dc->last_ier, dc->reg_ier);
			dev_err(&dc->pdev->dev, "Could not read status from "
				"card, we should disable interface\n");
		} else {
			writew(RESET, dc->reg_fcr);
		}
		/* No more useful info if this was the reset interrupt. */
		goto exit_handler;
	}
	if (read_iir & CTRL_UL) {
		DBG1("CTRL_UL");
		dc->last_ier &= ~CTRL_UL;
		writew(dc->last_ier, dc->reg_ier);
		if (send_flow_control(dc)) {
			writew(CTRL_UL, dc->reg_fcr);
			dc->last_ier = dc->last_ier | CTRL_UL;
			writew(dc->last_ier, dc->reg_ier);
		}
	}
	if (read_iir & CTRL_DL) {
		receive_flow_control(dc);
		writew(CTRL_DL, dc->reg_fcr);
	}
	if (read_iir & MDM_DL) {
		if (!handle_data_dl(dc, PORT_MDM,
				&(dc->port[PORT_MDM].toggle_dl), read_iir,
				MDM_DL1, MDM_DL2)) {
			dev_err(&dc->pdev->dev, "MDM_DL out of sync!\n");
			goto exit_handler;
		}
	}
	if (read_iir & MDM_UL) {
		if (!handle_data_ul(dc, PORT_MDM, read_iir)) {
			dev_err(&dc->pdev->dev, "MDM_UL out of sync!\n");
			goto exit_handler;
		}
	}
	if (read_iir & DIAG_DL) {
		if (!handle_data_dl(dc, PORT_DIAG,
				&(dc->port[PORT_DIAG].toggle_dl), read_iir,
				DIAG_DL1, DIAG_DL2)) {
			dev_err(&dc->pdev->dev, "DIAG_DL out of sync!\n");
			goto exit_handler;
		}
	}
	if (read_iir & DIAG_UL) {
		dc->last_ier &= ~DIAG_UL;
		writew(dc->last_ier, dc->reg_ier);
		if (send_data(PORT_DIAG, dc)) {
			writew(DIAG_UL, dc->reg_fcr);
			dc->last_ier = dc->last_ier | DIAG_UL;
			writew(dc->last_ier, dc->reg_ier);
		}
	}
	if (read_iir & APP1_DL) {
		if (receive_data(PORT_APP1, dc))
			writew(APP1_DL, dc->reg_fcr);
	}
	if (read_iir & APP1_UL) {
		dc->last_ier &= ~APP1_UL;
		writew(dc->last_ier, dc->reg_ier);
		if (send_data(PORT_APP1, dc)) {
			writew(APP1_UL, dc->reg_fcr);
			dc->last_ier = dc->last_ier | APP1_UL;
			writew(dc->last_ier, dc->reg_ier);
		}
	}
	if (read_iir & APP2_DL) {
		if (receive_data(PORT_APP2, dc))
			writew(APP2_DL, dc->reg_fcr);
	}
	if (read_iir & APP2_UL) {
		dc->last_ier &= ~APP2_UL;
		writew(dc->last_ier, dc->reg_ier);
		if (send_data(PORT_APP2, dc)) {
			writew(APP2_UL, dc->reg_fcr);
			dc->last_ier = dc->last_ier | APP2_UL;
			writew(dc->last_ier, dc->reg_ier);
		}
	}

exit_handler:
	spin_unlock(&dc->spin_mutex);

	for (a = 0; a < NOZOMI_MAX_PORTS; a++)
		if (test_and_clear_bit(a, &dc->flip))
			tty_flip_buffer_push(&dc->port[a].port);

	return IRQ_HANDLED;
none:
	spin_unlock(&dc->spin_mutex);
	return IRQ_NONE;
}