linux-kernel - Re: [PATCH v6] arm pl011 serial: support multi-irq request

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Message-ID: <YRYc9nCcpGOs4SaJ@kroah.com>
Date:   Fri, 13 Aug 2021 09:19:18 +0200
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Bing Fan <hptsfb@...il.com>
Cc:     linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6] arm pl011 serial: support multi-irq request

On Fri, Aug 13, 2021 at 11:31:30AM +0800, Bing Fan wrote:
> From: Bing Fan <tombinfan@...cent.com>
> 
> In order to make pl011 work better, multiple interrupts are
> required, such as TXIM, RXIM, RTIM, error interrupt(FE/PE/BE/OE);
> at the same time, pl011 to GIC does not merge the interrupt
> lines(each serial-interrupt corresponding to different GIC hardware
> interrupt), so need to enable and request multiple gic interrupt
> numbers in the driver.
> 
> Signed-off-by: Bing Fan <tombinfan@...cent.com>
> ---
>  drivers/tty/serial/amba-pl011.c | 39 +++++++++++++++++++++++++++++++--
>  1 file changed, 37 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
> index e14f3378b8a0..eaac3431459c 100644
> --- a/drivers/tty/serial/amba-pl011.c
> +++ b/drivers/tty/serial/amba-pl011.c
> @@ -1701,6 +1701,41 @@ static void pl011_write_lcr_h(struct uart_amba_port *uap, unsigned int lcr_h)
>  	}
>  }
>  
> +static void pl011_release_multi_irqs(struct uart_amba_port *uap, unsigned int max_cnt)
> +{
> +	struct amba_device *amba_dev = container_of(uap->port.dev, struct amba_device, dev);
> +	int i;
> +
> +	for (i = 0; i < max_cnt; i++)
> +		if (amba_dev->irq[i])
> +			free_irq(amba_dev->irq[i], uap);
> +}
> +
> +static int pl011_allocate_multi_irqs(struct uart_amba_port *uap)
> +{
> +	int ret = 0;
> +	int i;
> +	unsigned int virq;
> +	struct amba_device *amba_dev = container_of(uap->port.dev, struct amba_device, dev);
> +
> +	pl011_write(uap->im, uap, REG_IMSC);
> +
> +	for (i = 0; i < AMBA_NR_IRQS; i++) {
> +		virq = amba_dev->irq[i];
> +		if (virq == 0)
> +			break;
> +
> +		ret = request_irq(virq, pl011_int, IRQF_SHARED, dev_name(&amba_dev->dev), uap);
> +		if (ret) {
> +			dev_err(uap->port.dev, "request %u interrupt failed\n", virq);
> +			pl011_release_multi_irqs(uap, i - 1);
> +			break;
> +		}
> +	}
> +
> +	return ret;
> +}

This function looks identical to pl011_allocate_irq(), so what is the
difference here?  Why is this still needed at all?  What does it do that
is different from pl011_allocate_irq()?

confused,

greg k-h