linux-kernel - Re: [RFC PATCH] serial: samsung: Re-factors UART IRQ resource for various Samsung SoC

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Date:   Mon, 15 Jun 2020 14:13:09 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     Tamseel Shams <m.shams@...sung.com>, kgene@...nel.org,
        krzk@...nel.org, gregkh@...uxfoundation.org, jslaby@...e.com
Cc:     linux-samsung-soc@...r.kernel.org, linux-serial@...r.kernel.org,
        linux-kernel@...r.kernel.org, alim.akhtar@...sung.com,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [RFC PATCH] serial: samsung: Re-factors UART IRQ resource for
 various Samsung SoC

On 2020-06-15 13:26, Tamseel Shams wrote:
> In few older Samsung SoCs like s3c2410, s3c2412
> and s3c2440, UART IP is having 2 interrupt lines.
> However, in other SoCs like s3c6400, s5pv210,
> exynos5433, and exynos4210 UART is having only 1
> interrupt line. Due to this, "platform_get_irq(platdev, 1)"
> call in the driver gives the following warning:
> "IRQ index 1 not found" on recent platforms.
> 
> This patch re-factors the IRQ resources handling for
> each platform and hence fixing the above warnings seen
> on some platforms.
> 
> Signed-off-by: Tamseel Shams <m.shams@...sung.com>
> ---
>   drivers/tty/serial/samsung_tty.c | 20 ++++++++++++++++----
>   1 file changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
> index 6ef614d8648c..078dcb3e316f 100644
> --- a/drivers/tty/serial/samsung_tty.c
> +++ b/drivers/tty/serial/samsung_tty.c
> @@ -60,6 +60,7 @@ struct s3c24xx_uart_info {
>   	char			*name;
>   	unsigned int		type;
>   	unsigned int		fifosize;
> +	unsigned int		irq_cnt;
>   	unsigned long		rx_fifomask;
>   	unsigned long		rx_fifoshift;
>   	unsigned long		rx_fifofull;
> @@ -1908,12 +1909,17 @@ static int s3c24xx_serial_init_port(struct s3c24xx_uart_port *ourport,
>   	else {
>   		port->irq = ret;
>   		ourport->rx_irq = ret;
> -		ourport->tx_irq = ret + 1;
> +		if (ourport->info->irq_cnt == 1)
> +			ourport->tx_irq = ret;
> +		else
> +			ourport->tx_irq = ret + 1;
>   	}
>   
> -	ret = platform_get_irq(platdev, 1);
> -	if (ret > 0)
> -		ourport->tx_irq = ret;
> +	if (ourport->info->irq_cnt != 1) {
> +		ret = platform_get_irq(platdev, 1);
> +		if (ret > 0)
> +			ourport->tx_irq = ret;

FWIW, if you're not going to do anything in the error case then you may 
as well just call platform_get_irq_optional() unconditionally.

Robin.

> +	}
>   	/*
>   	 * DMA is currently supported only on DT platforms, if DMA properties
>   	 * are specified.
> @@ -2387,6 +2393,7 @@ static struct s3c24xx_serial_drv_data s3c2410_serial_drv_data = {
>   		.name		= "Samsung S3C2410 UART",
>   		.type		= PORT_S3C2410,
>   		.fifosize	= 16,
> +		.irq_cnt	= 2,
>   		.rx_fifomask	= S3C2410_UFSTAT_RXMASK,
>   		.rx_fifoshift	= S3C2410_UFSTAT_RXSHIFT,
>   		.rx_fifofull	= S3C2410_UFSTAT_RXFULL,
> @@ -2414,6 +2421,7 @@ static struct s3c24xx_serial_drv_data s3c2412_serial_drv_data = {
>   		.name		= "Samsung S3C2412 UART",
>   		.type		= PORT_S3C2412,
>   		.fifosize	= 64,
> +		.irq_cnt	= 2,
>   		.has_divslot	= 1,
>   		.rx_fifomask	= S3C2440_UFSTAT_RXMASK,
>   		.rx_fifoshift	= S3C2440_UFSTAT_RXSHIFT,
> @@ -2443,6 +2451,7 @@ static struct s3c24xx_serial_drv_data s3c2440_serial_drv_data = {
>   		.name		= "Samsung S3C2440 UART",
>   		.type		= PORT_S3C2440,
>   		.fifosize	= 64,
> +		.irq_cnt	= 2,
>   		.has_divslot	= 1,
>   		.rx_fifomask	= S3C2440_UFSTAT_RXMASK,
>   		.rx_fifoshift	= S3C2440_UFSTAT_RXSHIFT,
> @@ -2471,6 +2480,7 @@ static struct s3c24xx_serial_drv_data s3c6400_serial_drv_data = {
>   		.name		= "Samsung S3C6400 UART",
>   		.type		= PORT_S3C6400,
>   		.fifosize	= 64,
> +		.irq_cnt	= 1,
>   		.has_divslot	= 1,
>   		.rx_fifomask	= S3C2440_UFSTAT_RXMASK,
>   		.rx_fifoshift	= S3C2440_UFSTAT_RXSHIFT,
> @@ -2498,6 +2508,7 @@ static struct s3c24xx_serial_drv_data s5pv210_serial_drv_data = {
>   	.info = &(struct s3c24xx_uart_info) {
>   		.name		= "Samsung S5PV210 UART",
>   		.type		= PORT_S3C6400,
> +		.irq_cnt	= 1,
>   		.has_divslot	= 1,
>   		.rx_fifomask	= S5PV210_UFSTAT_RXMASK,
>   		.rx_fifoshift	= S5PV210_UFSTAT_RXSHIFT,
> @@ -2526,6 +2537,7 @@ static struct s3c24xx_serial_drv_data s5pv210_serial_drv_data = {
>   	.info = &(struct s3c24xx_uart_info) {			\
>   		.name		= "Samsung Exynos UART",	\
>   		.type		= PORT_S3C6400,			\
> +		.irq_cnt	= 1,				\
>   		.has_divslot	= 1,				\
>   		.rx_fifomask	= S5PV210_UFSTAT_RXMASK,	\
>   		.rx_fifoshift	= S5PV210_UFSTAT_RXSHIFT,	\
>