linux-kernel - Re: [PATCH net-next v1 3/4] net: stmmac: Add support for TX/RX channel interrupt

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Message-ID: <qyiveqz3egzctymkwflgw4u6ubnpiss2x244fsepop7t3ve7ev@7x24oaiferuy>
Date: Sat, 23 Dec 2023 00:49:10 +0300
From: Serge Semin <fancer.lancer@...il.com>
To: Leong Ching Swee <leong.ching.swee@...el.com>
Cc: Maxime Coquelin <mcoquelin.stm32@...il.com>, 
	Alexandre Torgue <alexandre.torgue@...s.st.com>, Jose Abreu <joabreu@...opsys.com>, 
	"David S . Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
	Rob Herring <robh+dt@...nel.org>, Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, 
	Conor Dooley <conor+dt@...nel.org>, Giuseppe Cavallaro <peppe.cavallaro@...com>, 
	linux-stm32@...md-mailman.stormreply.com, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org, devicetree@...r.kernel.org, 
	Teoh Ji Sheng <ji.sheng.teoh@...el.com>
Subject: Re: [PATCH net-next v1 3/4] net: stmmac: Add support for TX/RX
 channel interrupt

On Fri, Dec 22, 2023 at 01:44:50PM +0800, Leong Ching Swee wrote:
> From: Swee Leong Ching <leong.ching.swee@...el.com>
> 
> Enable TX/RX channel interrupt registration for MAC that interrupts CPU
> through shared peripheral interrupt (SPI).
> 
> Per channel interrupts and interrupt-names are registered through,
> Eg: 4 tx and 4 rx channels:
> interrupts = <GIC_SPI 100 IRQ_TYPE_LEVEL_HIGH>,
>              <GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>,
>              <GIC_SPI 102 IRQ_TYPE_LEVEL_HIGH>,
>              <GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>;
>              <GIC_SPI 104 IRQ_TYPE_LEVEL_HIGH>;
>              <GIC_SPI 105 IRQ_TYPE_LEVEL_HIGH>;
>              <GIC_SPI 106 IRQ_TYPE_LEVEL_HIGH>;
>              <GIC_SPI 107 IRQ_TYPE_LEVEL_HIGH>;
> interrupt-names = "dma_tx0",
>                   "dma_tx1",
>                   "dma_tx2",
>                   "dma_tx3",
>                   "dma_rx0",
>                   "dma_rx1",
>                   "dma_rx2",
>                   "dma_rx3";
> 
> Signed-off-by: Teoh Ji Sheng <ji.sheng.teoh@...el.com>
> Signed-off-by: Swee Leong Ching <leong.ching.swee@...el.com>
> ---
>  .../ethernet/stmicro/stmmac/stmmac_platform.c | 24 +++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> index 70eadc83ca68..f857907f13a0 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> @@ -710,6 +710,8 @@ EXPORT_SYMBOL_GPL(devm_stmmac_probe_config_dt);
>  int stmmac_get_platform_resources(struct platform_device *pdev,
>  				  struct stmmac_resources *stmmac_res)
>  {

> +	char irq_name[8];

By DW XGMAC v2.x IP-core design there can be up to 16 Tx channels and
12 Rx channels. Thus it's better to set irq_name size being at least
(strlen("dma_tx16") + 1) == 9 beforehand since you are adding this
code anyway and for some reason didn't consider to pick the Jisheng'
patch up which fixed the MTL_MAX_TX_QUEUES/MTL_MAX_RX_QUEUES macros.

> +	int i;

Please add an empty line between the variables declaration and the
next statement.

>  	memset(stmmac_res, 0, sizeof(*stmmac_res));
>  
>  	/* Get IRQ information early to have an ability to ask for deferred
> @@ -719,6 +721,28 @@ int stmmac_get_platform_resources(struct platform_device *pdev,
>  	if (stmmac_res->irq < 0)
>  		return stmmac_res->irq;
>  

> +	/* For RX Channel */
> +	for (i = 0; i < MTL_MAX_RX_QUEUES; i++) {
> +		snprintf(irq_name, sizeof(irq_name), "dma_rx%i", i);
> +		stmmac_res->rx_irq[i] = platform_get_irq_byname_optional(pdev, irq_name);
> +		if (stmmac_res->rx_irq[i] < 0) {
> +			if (stmmac_res->rx_irq[i] == -EPROBE_DEFER)
> +				return -EPROBE_DEFER;
> +			break;
> +		}
> +	}

What about:

+	/* Get optional Tx/Rx DMA per-channel IRQs, which otherwise
+	 * are supposed to be delivered via the common MAC IRQ line
+	 */
+	for (i = 0; i < MTL_MAX_RX_QUEUES; i++) {
+		snprintf(irq_name, sizeof(irq_name), "dma_rx%i", i);
+		irq = platform_get_irq_byname_optional(pdev, irq_name);
+		if (irq == -EPROBE_DEFER)
+			return irq;
+		else if (irq < 0)
+			break;
+
+		stmmac_res->rx_irq[i] = irq;
+	}

It's cleaner a bit with less indentations and doesn't pollute
rx_irq[]/tx_irq[] arrays with the error numbers.

> +
> +	/* For TX Channel */
> +	for (i = 0; i < MTL_MAX_TX_QUEUES; i++) {
> +		snprintf(irq_name, sizeof(irq_name), "dma_tx%i", i);
> +		stmmac_res->tx_irq[i] = platform_get_irq_byname_optional(pdev, irq_name);
> +		if (stmmac_res->tx_irq[i] < 0) {
> +			if (stmmac_res->rx_irq[i] == -EPROBE_DEFER)
> +				return -EPROBE_DEFER;
> +			break;
> +		}
> +	}
> +

Please move the Tx/Rx IRQs getting loops to the bottom of the
stmmac_get_platform_resources() method. Thus the order of the IRQs
getting would be the same as the order of the IRQs requests
implemented in the stmmac_request_irq_multi_msi() and
stmmac_request_irq_single() methods.

-Serge(y)

>  	/* On some platforms e.g. SPEAr the wake up irq differs from the mac irq
>  	 * The external wake up irq can be passed through the platform code
>  	 * named as "eth_wake_irq"
> -- 
> 2.34.1
> 
>