Re: [PATCH v4 2/2] PCI: Rockchip: Add Rockchip PCIe controller support

From: Marc Zyngier
Date: Fri Jul 01 2016 - 06:46:46 EST


On 01/07/16 02:24, Shawn Lin wrote:
> This patch adds Rockchip PCIe controller support found
> on RK3399 Soc platform.
>
> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
>
> ---

[...]

> +static void rockchip_pcie_legacy_int_handler(struct irq_desc *desc)
> +{
> + struct irq_chip *chip = irq_desc_get_chip(desc);
> + struct rockchip_pcie_port *port;
> + u32 reg;
> +
> + chained_irq_enter(chip, desc);
> + port = irq_desc_get_handler_data(desc);
> +
> + reg = pcie_read(port, PCIE_CLIENT_INT_STATUS);
> + reg = (reg & ROCKCHIP_PCIE_RPIFR1_INTR_MASK) >>
> + ROCKCHIP_PCIE_RPIFR1_INTR_SHIFT;
> + if (reg)
> + generic_handle_irq(irq_find_mapping(port->irq_domain,
> + ffs(reg)));

Can't you get multiple pending interrupts at the same time? Here, you
seem to only process one interrupt at a time, which is going to be
pretty inefficient.

How about something like:

while (reg) {
int hwirq = ffs(reg);
int irq;

reg &= ~BIT(hwirq);
irq = irq_find_mapping(port->irq_domain, hwirq);
if (irq)
generic_handle_irq(irq);
}

> + chained_irq_exit(chip, desc);
> +}
> +

Thanks,

M.
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