[RESEND PATCH v2] mfd: twl6030: Fix endianness problem in IRQ handler

[RESEND PATCH v2] mfd: twl6030: Fix endianness problem in IRQ handler

[Taras Kondratiuk]

From: Danke Xie <d.xie@sta.samsung.com>

The current TWL 6030 IRQ handler assumes little endianness.
This change makes it endian-neutral.

Signed-off-by: Danke Xie <d.xie@sta.samsung.com>
Signed-off-by: Taras Kondratiuk <taras.kondratiuk@linaro.org>
---
v2: fixed sparse warning
v1: https://patchwork.kernel.org/patch/2974331/

drivers/mfd/twl6030-irq.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/mfd/twl6030-irq.c b/drivers/mfd/twl6030-irq.c
index 517eda8..18a607e 100644
--- a/drivers/mfd/twl6030-irq.c
+++ b/drivers/mfd/twl6030-irq.c
@@ -176,8 +176,9 @@ static irqreturn_t twl6030_irq_thread(int irq, void *data)
 	int i, ret;
 	union {
 		u8 bytes[4];
-		u32 int_sts;
+		__le32 int_sts;
 	} sts;
+	u32 int_sts; /* sts.int_sts converted to CPU endianness */
 	struct twl6030_irq *pdata = data;
 
 	/* read INT_STS_A, B and C in one shot using a burst read */
@@ -196,8 +197,9 @@ static irqreturn_t twl6030_irq_thread(int irq, void *data)
 	if (sts.bytes[2] & 0x10)
 		sts.bytes[2] |= 0x08;
 
-	for (i = 0; sts.int_sts; sts.int_sts >>= 1, i++)
-		if (sts.int_sts & 0x1) {
+	int_sts = le32_to_cpu(sts.int_sts);
+	for (i = 0; int_sts; int_sts >>= 1, i++)
+		if (int_sts & 0x1) {
 			int module_irq =
 				irq_find_mapping(pdata->irq_domain,
 						 pdata->irq_mapping_tbl[i]);
-- 
1.7.9.5

Re: [RESEND PATCH v2] mfd: twl6030: Fix endianness problem in IRQ handler

[Joe Perches]

On Mon, 2013-12-23 at 19:11 +0200, Taras Kondratiuk wrote:
> From: Danke Xie <d.xie@sta.samsung.com>
> 
> The current TWL 6030 IRQ handler assumes little endianness.
> This change makes it endian-neutral.
[]
> diff --git a/drivers/mfd/twl6030-irq.c b/drivers/mfd/twl6030-irq.c
[]
> @@ -196,8 +197,9 @@ static irqreturn_t twl6030_irq_thread(int irq, void *data)
>  	if (sts.bytes[2] & 0x10)
>  		sts.bytes[2] |= 0x08;
>  
> -	for (i = 0; sts.int_sts; sts.int_sts >>= 1, i++)
> -		if (sts.int_sts & 0x1) {
> +	int_sts = le32_to_cpu(sts.int_sts);
> +	for (i = 0; int_sts; int_sts >>= 1, i++)
> +		if (int_sts & 0x1) {
>  			int module_irq =
>  				irq_find_mapping(pdata->irq_domain,
>  						 pdata->irq_mapping_tbl[i]);

instead of the

	for (...) {
		if (foo & 1) {
		

maybe using ffs would be better/faster

	while ((bit = ffs(int_sts))) {

etc...

Re: [RESEND PATCH v2] mfd: twl6030: Fix endianness problem in IRQ handler

[Taras Kondratiuk]

On 23 December 2013 19:20, Joe Perches <joe@perches.com> wrote:
> On Mon, 2013-12-23 at 19:11 +0200, Taras Kondratiuk wrote:
>> From: Danke Xie <d.xie@sta.samsung.com>
>>
>> The current TWL 6030 IRQ handler assumes little endianness.
>> This change makes it endian-neutral.
> []
>> diff --git a/drivers/mfd/twl6030-irq.c b/drivers/mfd/twl6030-irq.c
> []
>> @@ -196,8 +197,9 @@ static irqreturn_t twl6030_irq_thread(int irq, void *data)
>>       if (sts.bytes[2] & 0x10)
>>               sts.bytes[2] |= 0x08;
>>
>> -     for (i = 0; sts.int_sts; sts.int_sts >>= 1, i++)
>> -             if (sts.int_sts & 0x1) {
>> +     int_sts = le32_to_cpu(sts.int_sts);
>> +     for (i = 0; int_sts; int_sts >>= 1, i++)
>> +             if (int_sts & 0x1) {
>>                       int module_irq =
>>                               irq_find_mapping(pdata->irq_domain,
>>                                                pdata->irq_mapping_tbl[i]);
>
> instead of the
>
>         for (...) {
>                 if (foo & 1) {
>
>
> maybe using ffs would be better/faster
>
>         while ((bit = ffs(int_sts))) {
>
> etc...

Makes sense, but the aim of this patch is to fix endianness issue.
This micro-optimisation can be done as a separate patch.

-- 
Regards,
Taras Kondratiuk

Re: [RESEND PATCH v2] mfd: twl6030: Fix endianness problem in IRQ handler

[Lee Jones]

On Mon, 23 Dec 2013, Taras Kondratiuk wrote:

> From: Danke Xie <d.xie@sta.samsung.com>
> 
> The current TWL 6030 IRQ handler assumes little endianness.
> This change makes it endian-neutral.
> 
> Signed-off-by: Danke Xie <d.xie@sta.samsung.com>
> Signed-off-by: Taras Kondratiuk <taras.kondratiuk@linaro.org>
> ---
> v2: fixed sparse warning
> v1: https://patchwork.kernel.org/patch/2974331/
> 
> drivers/mfd/twl6030-irq.c |    8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)

Applied, thanks.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
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