Patchwork [17/30] PCI: tegra: Use switch statements in tegra_pcie_isr()

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Submitter Manikanta Maddireddy
Date April 11, 2019, 5:03 p.m.
Message ID <20190411170355.6882-18-mmaddireddy@nvidia.com>
Download mbox | patch
Permalink /patch/770845/
State New
Headers show

Comments

Manikanta Maddireddy - April 11, 2019, 5:03 p.m.
Use switch statements in tegra_pcie_isr() for better code readability.

Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
---
 drivers/pci/controller/pci-tegra.c | 37 ++++++++++++++++--------------
 1 file changed, 20 insertions(+), 17 deletions(-)
Thierry Reding - April 15, 2019, 1:25 p.m.
On Thu, Apr 11, 2019 at 10:33:42PM +0530, Manikanta Maddireddy wrote:
> Use switch statements in tegra_pcie_isr() for better code readability.
> 
> Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
> ---
>  drivers/pci/controller/pci-tegra.c | 37 ++++++++++++++++--------------
>  1 file changed, 20 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
> index cdaaf13a9fd7..cf2715065a53 100644
> --- a/drivers/pci/controller/pci-tegra.c
> +++ b/drivers/pci/controller/pci-tegra.c
> @@ -842,36 +842,39 @@ static irqreturn_t tegra_pcie_isr(int irq, void *arg)
>  	};
>  	struct tegra_pcie *pcie = arg;
>  	struct device *dev = pcie->dev;
> -	u32 code, signature;
> +	u32 code, signature, fpci;
> +	u64 address;
>  
>  	code = afi_readl(pcie, AFI_INTR_CODE) & AFI_INTR_CODE_MASK;
>  	signature = afi_readl(pcie, AFI_INTR_SIGNATURE);
>  	afi_writel(pcie, 0, AFI_INTR_CODE);
>  
> -	if (code == AFI_INTR_LEGACY)
> -		return IRQ_NONE;
> -
>  	if (code >= ARRAY_SIZE(err_msg))
> -		code = 0;
> +		return IRQ_NONE;
>  
> +	switch (code) {
> +	case AFI_INTR_LEGACY:
> +		return IRQ_NONE;
>  	/*
>  	 * do not pollute kernel log with master abort reports since they
>  	 * happen a lot during enumeration
>  	 */
> -	if (code == AFI_INTR_MASTER_ABORT)
> +	case AFI_INTR_MASTER_ABORT:
>  		dev_dbg(dev, "%s, signature: %08x\n", err_msg[code], signature);
> -	else
> +		fpci = afi_readl(pcie, AFI_UPPER_FPCI_ADDRESS) & 0xff;
> +		address = (u64)fpci << 32 | (signature & 0xfffffffc);
> +		dev_dbg(dev, "  FPCI address: %10llx\n", address);
> +		break;
> +	case AFI_INTR_TARGET_ABORT:
> +	case AFI_INTR_FPCI_DECODE_ERROR:
>  		dev_err(dev, "%s, signature: %08x\n", err_msg[code], signature);
> -
> -	if (code == AFI_INTR_TARGET_ABORT || code == AFI_INTR_MASTER_ABORT ||
> -	    code == AFI_INTR_FPCI_DECODE_ERROR) {
> -		u32 fpci = afi_readl(pcie, AFI_UPPER_FPCI_ADDRESS) & 0xff;
> -		u64 address = (u64)fpci << 32 | (signature & 0xfffffffc);
> -
> -		if (code == AFI_INTR_MASTER_ABORT)
> -			dev_dbg(dev, "  FPCI address: %10llx\n", address);
> -		else
> -			dev_err(dev, "  FPCI address: %10llx\n", address);
> +		fpci = afi_readl(pcie, AFI_UPPER_FPCI_ADDRESS) & 0xff;
> +		address = (u64)fpci << 32 | (signature & 0xfffffffc);
> +		dev_err(dev, "  FPCI address: %10llx\n", address);
> +		break;
> +	default:
> +		dev_err(dev, "%s, signature: %08x\n", err_msg[code], signature);
> +		break;
>  	}
>  
>  	return IRQ_HANDLED;

I don't think this improves readability. It does duplicate some code and
is actually longer than the previous variant, so I don't think this adds
value.

Thierry
Manikanta Maddireddy - April 15, 2019, 3:25 p.m.
On 15-Apr-19 6:55 PM, Thierry Reding wrote:
> On Thu, Apr 11, 2019 at 10:33:42PM +0530, Manikanta Maddireddy wrote:
>> Use switch statements in tegra_pcie_isr() for better code readability.
>>
>> Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
>> ---
>>  drivers/pci/controller/pci-tegra.c | 37 ++++++++++++++++--------------
>>  1 file changed, 20 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
>> index cdaaf13a9fd7..cf2715065a53 100644
>> --- a/drivers/pci/controller/pci-tegra.c
>> +++ b/drivers/pci/controller/pci-tegra.c
>> @@ -842,36 +842,39 @@ static irqreturn_t tegra_pcie_isr(int irq, void *arg)
>>  	};
>>  	struct tegra_pcie *pcie = arg;
>>  	struct device *dev = pcie->dev;
>> -	u32 code, signature;
>> +	u32 code, signature, fpci;
>> +	u64 address;
>>  
>>  	code = afi_readl(pcie, AFI_INTR_CODE) & AFI_INTR_CODE_MASK;
>>  	signature = afi_readl(pcie, AFI_INTR_SIGNATURE);
>>  	afi_writel(pcie, 0, AFI_INTR_CODE);
>>  
>> -	if (code == AFI_INTR_LEGACY)
>> -		return IRQ_NONE;
>> -
>>  	if (code >= ARRAY_SIZE(err_msg))
>> -		code = 0;
>> +		return IRQ_NONE;
>>  
>> +	switch (code) {
>> +	case AFI_INTR_LEGACY:
>> +		return IRQ_NONE;
>>  	/*
>>  	 * do not pollute kernel log with master abort reports since they
>>  	 * happen a lot during enumeration
>>  	 */
>> -	if (code == AFI_INTR_MASTER_ABORT)
>> +	case AFI_INTR_MASTER_ABORT:
>>  		dev_dbg(dev, "%s, signature: %08x\n", err_msg[code], signature);
>> -	else
>> +		fpci = afi_readl(pcie, AFI_UPPER_FPCI_ADDRESS) & 0xff;
>> +		address = (u64)fpci << 32 | (signature & 0xfffffffc);
>> +		dev_dbg(dev, "  FPCI address: %10llx\n", address);
>> +		break;
>> +	case AFI_INTR_TARGET_ABORT:
>> +	case AFI_INTR_FPCI_DECODE_ERROR:
>>  		dev_err(dev, "%s, signature: %08x\n", err_msg[code], signature);
>> -
>> -	if (code == AFI_INTR_TARGET_ABORT || code == AFI_INTR_MASTER_ABORT ||
>> -	    code == AFI_INTR_FPCI_DECODE_ERROR) {
>> -		u32 fpci = afi_readl(pcie, AFI_UPPER_FPCI_ADDRESS) & 0xff;
>> -		u64 address = (u64)fpci << 32 | (signature & 0xfffffffc);
>> -
>> -		if (code == AFI_INTR_MASTER_ABORT)
>> -			dev_dbg(dev, "  FPCI address: %10llx\n", address);
>> -		else
>> -			dev_err(dev, "  FPCI address: %10llx\n", address);
>> +		fpci = afi_readl(pcie, AFI_UPPER_FPCI_ADDRESS) & 0xff;
>> +		address = (u64)fpci << 32 | (signature & 0xfffffffc);
>> +		dev_err(dev, "  FPCI address: %10llx\n", address);
>> +		break;
>> +	default:
>> +		dev_err(dev, "%s, signature: %08x\n", err_msg[code], signature);
>> +		break;
>>  	}
>>  
>>  	return IRQ_HANDLED;
> I don't think this improves readability. It does duplicate some code and
> is actually longer than the previous variant, so I don't think this adds
> value.
>
> Thierry
There is multiple conditions check in single "if" statement and there is if-else statement
inside "if", so I felt switch case makes it more clear. I agree there is duplicate code.

Manikanta

Patch

diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
index cdaaf13a9fd7..cf2715065a53 100644
--- a/drivers/pci/controller/pci-tegra.c
+++ b/drivers/pci/controller/pci-tegra.c
@@ -842,36 +842,39 @@  static irqreturn_t tegra_pcie_isr(int irq, void *arg)
 	};
 	struct tegra_pcie *pcie = arg;
 	struct device *dev = pcie->dev;
-	u32 code, signature;
+	u32 code, signature, fpci;
+	u64 address;
 
 	code = afi_readl(pcie, AFI_INTR_CODE) & AFI_INTR_CODE_MASK;
 	signature = afi_readl(pcie, AFI_INTR_SIGNATURE);
 	afi_writel(pcie, 0, AFI_INTR_CODE);
 
-	if (code == AFI_INTR_LEGACY)
-		return IRQ_NONE;
-
 	if (code >= ARRAY_SIZE(err_msg))
-		code = 0;
+		return IRQ_NONE;
 
+	switch (code) {
+	case AFI_INTR_LEGACY:
+		return IRQ_NONE;
 	/*
 	 * do not pollute kernel log with master abort reports since they
 	 * happen a lot during enumeration
 	 */
-	if (code == AFI_INTR_MASTER_ABORT)
+	case AFI_INTR_MASTER_ABORT:
 		dev_dbg(dev, "%s, signature: %08x\n", err_msg[code], signature);
-	else
+		fpci = afi_readl(pcie, AFI_UPPER_FPCI_ADDRESS) & 0xff;
+		address = (u64)fpci << 32 | (signature & 0xfffffffc);
+		dev_dbg(dev, "  FPCI address: %10llx\n", address);
+		break;
+	case AFI_INTR_TARGET_ABORT:
+	case AFI_INTR_FPCI_DECODE_ERROR:
 		dev_err(dev, "%s, signature: %08x\n", err_msg[code], signature);
-
-	if (code == AFI_INTR_TARGET_ABORT || code == AFI_INTR_MASTER_ABORT ||
-	    code == AFI_INTR_FPCI_DECODE_ERROR) {
-		u32 fpci = afi_readl(pcie, AFI_UPPER_FPCI_ADDRESS) & 0xff;
-		u64 address = (u64)fpci << 32 | (signature & 0xfffffffc);
-
-		if (code == AFI_INTR_MASTER_ABORT)
-			dev_dbg(dev, "  FPCI address: %10llx\n", address);
-		else
-			dev_err(dev, "  FPCI address: %10llx\n", address);
+		fpci = afi_readl(pcie, AFI_UPPER_FPCI_ADDRESS) & 0xff;
+		address = (u64)fpci << 32 | (signature & 0xfffffffc);
+		dev_err(dev, "  FPCI address: %10llx\n", address);
+		break;
+	default:
+		dev_err(dev, "%s, signature: %08x\n", err_msg[code], signature);
+		break;
 	}
 
 	return IRQ_HANDLED;