Re: [PATCH 2/4] PCI: mvebu: Implement support for interrupts on emulated bridge

[Andrew Lunn <andrew@lunn.ch>]

> -static irqreturn_t mvebu_pcie_irq_handler(int irq, void *arg)
> +static irqreturn_t mvebu_pcie_error_irq_handler(int irq, void *arg)
> +{
> +	struct mvebu_pcie_port *port = arg;
> +	struct device *dev = &port->pcie->pdev->dev;
> +	u32 cause, unmask, status;
> +
> +	cause = mvebu_readl(port, PCIE_INT_CAUSE_OFF);
> +	unmask = mvebu_readl(port, PCIE_INT_UNMASK_OFF);
> +	status = cause & unmask;
> +
> +	/* "error" interrupt handler does not process INTX interrupts */
> +	status &= ~(PCIE_INT_INTX(0) | PCIE_INT_INTX(1) |
> +		    PCIE_INT_INTX(2) | PCIE_INT_INTX(3));

Just for my understanding...

There are two interrupts, but the status information what those
interrupts actually mean are all packed into one register? I assume
reading the clause register does not clear set bits? Otherwise there
would be a race condition. Are these actually level interrupts, and in
order to clear them you need to poke some other register?

> +	/*
> +	 * Old DT bindings do not contain "error" interrupt
> +	 * so do not fail probing driver when interrupt does not exist.
> +	 */
> +	port->error_irq = of_irq_get_byname(child, "error");
> +	if (port->error_irq == -EPROBE_DEFER) {
> +		ret = port->error_irq;
> +		goto err;
> +	}
> +	if (port->error_irq <= 0) {
> +		dev_warn(dev, "%s: interrupts on Root Port are unsupported, "

Maybe that should be "Error interrupts on Root..." ?

      Andrew