2022-10-06 05:56:22

by Christophe Leroy

[permalink] [raw]
Subject: [PATCH] usb: Replace NO_IRQ by 0

NO_IRQ is used to check the return of irq_of_parse_and_map().

On some architecture NO_IRQ is 0, on other architectures it is -1.

irq_of_parse_and_map() returns 0 on error, independent of NO_IRQ.

So use 0 instead of using NO_IRQ.

Signed-off-by: Christophe Leroy <[email protected]>
---
drivers/usb/host/ehci-grlib.c | 2 +-
drivers/usb/host/ehci-ppc-of.c | 2 +-
drivers/usb/host/fhci-hcd.c | 2 +-
drivers/usb/host/ohci-ppc-of.c | 2 +-
drivers/usb/host/uhci-grlib.c | 2 +-
5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/host/ehci-grlib.c b/drivers/usb/host/ehci-grlib.c
index a2c3b4ec8a8b..0717f2ccf49d 100644
--- a/drivers/usb/host/ehci-grlib.c
+++ b/drivers/usb/host/ehci-grlib.c
@@ -99,7 +99,7 @@ static int ehci_hcd_grlib_probe(struct platform_device *op)
hcd->rsrc_len = resource_size(&res);

irq = irq_of_parse_and_map(dn, 0);
- if (irq == NO_IRQ) {
+ if (!irq) {
dev_err(&op->dev, "%s: irq_of_parse_and_map failed\n",
__FILE__);
rv = -EBUSY;
diff --git a/drivers/usb/host/ehci-ppc-of.c b/drivers/usb/host/ehci-ppc-of.c
index 28a19693c19f..62a0a193798c 100644
--- a/drivers/usb/host/ehci-ppc-of.c
+++ b/drivers/usb/host/ehci-ppc-of.c
@@ -119,7 +119,7 @@ static int ehci_hcd_ppc_of_probe(struct platform_device *op)
hcd->rsrc_len = resource_size(&res);

irq = irq_of_parse_and_map(dn, 0);
- if (irq == NO_IRQ) {
+ if (!irq) {
dev_err(&op->dev, "%s: irq_of_parse_and_map failed\n",
__FILE__);
rv = -EBUSY;
diff --git a/drivers/usb/host/fhci-hcd.c b/drivers/usb/host/fhci-hcd.c
index 2ba09c3fbc2f..6d3215a3ef81 100644
--- a/drivers/usb/host/fhci-hcd.c
+++ b/drivers/usb/host/fhci-hcd.c
@@ -693,7 +693,7 @@ static int of_fhci_probe(struct platform_device *ofdev)

/* USB Host interrupt. */
usb_irq = irq_of_parse_and_map(node, 0);
- if (usb_irq == NO_IRQ) {
+ if (!usb_irq) {
dev_err(dev, "could not get usb irq\n");
ret = -EINVAL;
goto err_usb_irq;
diff --git a/drivers/usb/host/ohci-ppc-of.c b/drivers/usb/host/ohci-ppc-of.c
index 591f675cc930..f2f6c832ec98 100644
--- a/drivers/usb/host/ohci-ppc-of.c
+++ b/drivers/usb/host/ohci-ppc-of.c
@@ -120,7 +120,7 @@ static int ohci_hcd_ppc_of_probe(struct platform_device *op)
}

irq = irq_of_parse_and_map(dn, 0);
- if (irq == NO_IRQ) {
+ if (!irq) {
dev_err(&op->dev, "%s: irq_of_parse_and_map failed\n",
__FILE__);
rv = -EBUSY;
diff --git a/drivers/usb/host/uhci-grlib.c b/drivers/usb/host/uhci-grlib.c
index 3ef6d52839e5..907d5f01edfd 100644
--- a/drivers/usb/host/uhci-grlib.c
+++ b/drivers/usb/host/uhci-grlib.c
@@ -116,7 +116,7 @@ static int uhci_hcd_grlib_probe(struct platform_device *op)
hcd->rsrc_len = resource_size(&res);

irq = irq_of_parse_and_map(dn, 0);
- if (irq == NO_IRQ) {
+ if (!irq) {
printk(KERN_ERR "%s: irq_of_parse_and_map failed\n", __FILE__);
rv = -EBUSY;
goto err_usb;
--
2.37.1


2022-10-06 14:08:35

by Christophe Leroy

[permalink] [raw]
Subject: Re: [PATCH] usb: Replace NO_IRQ by 0



Le 06/10/2022 à 15:50, Alan Stern a écrit :
> On Thu, Oct 06, 2022 at 07:15:44AM +0200, Christophe Leroy wrote:
>> NO_IRQ is used to check the return of irq_of_parse_and_map().
>>
>> On some architecture NO_IRQ is 0, on other architectures it is -1.
>>
>> irq_of_parse_and_map() returns 0 on error, independent of NO_IRQ.
>
> This isn't clear. Does absence of an irq count as an error? In other
> words, will irq_of_parse_and_map() sometimes return 0 and other times
> return NO_IRQ? What about architectures on which 0 is a valid irq
> number?

NO_IRQ doesn't exist anywhere in core functions. Only some drivers and
some architectures have relics of it.

irq_of_parse_and_map() will always return 0 on error.

0 can't be a valid logical IRQ number. It may only be a valid hwirq
number but it will always be translated to a non-zero logical irq number.

I'm trying to get rid of NO_IRQ completely in powerpc code, therefore
trying to clean-up all drivers used by powerpc architecture.

Long time ago Linus advocated for not using NO_IRQ, see
https://lkml.org/lkml/2005/11/21/221

Thanks
Christophe

>
>> So use 0 instead of using NO_IRQ.
>>
>> Signed-off-by: Christophe Leroy <[email protected]>
>> ---
>> drivers/usb/host/ehci-grlib.c | 2 +-
>> drivers/usb/host/ehci-ppc-of.c | 2 +-
>> drivers/usb/host/fhci-hcd.c | 2 +-
>> drivers/usb/host/ohci-ppc-of.c | 2 +-
>> drivers/usb/host/uhci-grlib.c | 2 +-
>> 5 files changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/usb/host/ehci-grlib.c b/drivers/usb/host/ehci-grlib.c
>> index a2c3b4ec8a8b..0717f2ccf49d 100644
>> --- a/drivers/usb/host/ehci-grlib.c
>> +++ b/drivers/usb/host/ehci-grlib.c
>> @@ -99,7 +99,7 @@ static int ehci_hcd_grlib_probe(struct platform_device *op)
>> hcd->rsrc_len = resource_size(&res);
>>
>> irq = irq_of_parse_and_map(dn, 0);
>> - if (irq == NO_IRQ) {
>> + if (!irq) {
>> dev_err(&op->dev, "%s: irq_of_parse_and_map failed\n",
>> __FILE__);
>> rv = -EBUSY;
>
> Since NO_IRQ is sometimes set to -1, shouldn't this test (and all the
> other ones you changed) really be doing:
>
> if (!irq || irq == NO_IRQ) { ...
>
> ?
>
> Alan Stern

2022-10-06 14:17:11

by Alan Stern

[permalink] [raw]
Subject: Re: [PATCH] usb: Replace NO_IRQ by 0

On Thu, Oct 06, 2022 at 07:15:44AM +0200, Christophe Leroy wrote:
> NO_IRQ is used to check the return of irq_of_parse_and_map().
>
> On some architecture NO_IRQ is 0, on other architectures it is -1.
>
> irq_of_parse_and_map() returns 0 on error, independent of NO_IRQ.

This isn't clear. Does absence of an irq count as an error? In other
words, will irq_of_parse_and_map() sometimes return 0 and other times
return NO_IRQ? What about architectures on which 0 is a valid irq
number?

> So use 0 instead of using NO_IRQ.
>
> Signed-off-by: Christophe Leroy <[email protected]>
> ---
> drivers/usb/host/ehci-grlib.c | 2 +-
> drivers/usb/host/ehci-ppc-of.c | 2 +-
> drivers/usb/host/fhci-hcd.c | 2 +-
> drivers/usb/host/ohci-ppc-of.c | 2 +-
> drivers/usb/host/uhci-grlib.c | 2 +-
> 5 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/usb/host/ehci-grlib.c b/drivers/usb/host/ehci-grlib.c
> index a2c3b4ec8a8b..0717f2ccf49d 100644
> --- a/drivers/usb/host/ehci-grlib.c
> +++ b/drivers/usb/host/ehci-grlib.c
> @@ -99,7 +99,7 @@ static int ehci_hcd_grlib_probe(struct platform_device *op)
> hcd->rsrc_len = resource_size(&res);
>
> irq = irq_of_parse_and_map(dn, 0);
> - if (irq == NO_IRQ) {
> + if (!irq) {
> dev_err(&op->dev, "%s: irq_of_parse_and_map failed\n",
> __FILE__);
> rv = -EBUSY;

Since NO_IRQ is sometimes set to -1, shouldn't this test (and all the
other ones you changed) really be doing:

if (!irq || irq == NO_IRQ) { ...

?

Alan Stern

2022-10-06 14:45:05

by Christophe Leroy

[permalink] [raw]
Subject: Re: [PATCH] usb: Replace NO_IRQ by 0



Le 06/10/2022 à 15:50, Alan Stern a écrit :
> On Thu, Oct 06, 2022 at 07:15:44AM +0200, Christophe Leroy wrote:
>> diff --git a/drivers/usb/host/ehci-grlib.c b/drivers/usb/host/ehci-grlib.c
>> index a2c3b4ec8a8b..0717f2ccf49d 100644
>> --- a/drivers/usb/host/ehci-grlib.c
>> +++ b/drivers/usb/host/ehci-grlib.c
>> @@ -99,7 +99,7 @@ static int ehci_hcd_grlib_probe(struct platform_device *op)
>> hcd->rsrc_len = resource_size(&res);
>>
>> irq = irq_of_parse_and_map(dn, 0);
>> - if (irq == NO_IRQ) {
>> + if (!irq) {
>> dev_err(&op->dev, "%s: irq_of_parse_and_map failed\n",
>> __FILE__);
>> rv = -EBUSY;
>
> Since NO_IRQ is sometimes set to -1, shouldn't this test (and all the
> other ones you changed) really be doing:
>
> if (!irq || irq == NO_IRQ) { ...
>

No, because irq_of_parse_and_map() will never return -1 as an error. It
will always be 0.

The below call gives no result.

git grep -w NO_IRQ drivers/of/ include/

2022-10-06 14:46:39

by Alan Stern

[permalink] [raw]
Subject: Re: [PATCH] usb: Replace NO_IRQ by 0

On Thu, Oct 06, 2022 at 02:01:57PM +0000, Christophe Leroy wrote:
>
>
> Le 06/10/2022 ? 15:50, Alan Stern a ?crit?:
> > On Thu, Oct 06, 2022 at 07:15:44AM +0200, Christophe Leroy wrote:
> >> NO_IRQ is used to check the return of irq_of_parse_and_map().
> >>
> >> On some architecture NO_IRQ is 0, on other architectures it is -1.
> >>
> >> irq_of_parse_and_map() returns 0 on error, independent of NO_IRQ.
> >
> > This isn't clear. Does absence of an irq count as an error? In other
> > words, will irq_of_parse_and_map() sometimes return 0 and other times
> > return NO_IRQ? What about architectures on which 0 is a valid irq
> > number?
>
> NO_IRQ doesn't exist anywhere in core functions. Only some drivers and
> some architectures have relics of it.
>
> irq_of_parse_and_map() will always return 0 on error.
>
> 0 can't be a valid logical IRQ number. It may only be a valid hwirq
> number but it will always be translated to a non-zero logical irq number.
>
> I'm trying to get rid of NO_IRQ completely in powerpc code, therefore
> trying to clean-up all drivers used by powerpc architecture.
>
> Long time ago Linus advocated for not using NO_IRQ, see
> https://lkml.org/lkml/2005/11/21/221

Okay, good. Please resubmit the patch and include some of these things
in the patch description.

Alan Stern

2022-11-10 18:53:02

by Christophe Leroy

[permalink] [raw]
Subject: Re: [PATCH] usb: Replace NO_IRQ by 0

Le 06/10/2022 à 16:24, Alan Stern a écrit :
> On Thu, Oct 06, 2022 at 02:01:57PM +0000, Christophe Leroy wrote:
>>
>>
>> Le 06/10/2022 à 15:50, Alan Stern a écrit :
>>> On Thu, Oct 06, 2022 at 07:15:44AM +0200, Christophe Leroy wrote:
>>>> NO_IRQ is used to check the return of irq_of_parse_and_map().
>>>>
>>>> On some architecture NO_IRQ is 0, on other architectures it is -1.
>>>>
>>>> irq_of_parse_and_map() returns 0 on error, independent of NO_IRQ.
>>>
>>> This isn't clear. Does absence of an irq count as an error? In other
>>> words, will irq_of_parse_and_map() sometimes return 0 and other times
>>> return NO_IRQ? What about architectures on which 0 is a valid irq
>>> number?
>>
>> NO_IRQ doesn't exist anywhere in core functions. Only some drivers and
>> some architectures have relics of it.
>>
>> irq_of_parse_and_map() will always return 0 on error.
>>
>> 0 can't be a valid logical IRQ number. It may only be a valid hwirq
>> number but it will always be translated to a non-zero logical irq number.
>>
>> I'm trying to get rid of NO_IRQ completely in powerpc code, therefore
>> trying to clean-up all drivers used by powerpc architecture.
>>
>> Long time ago Linus advocated for not using NO_IRQ, see
>> https://lkml.org/lkml/2005/11/21/221
>
> Okay, good. Please resubmit the patch and include some of these things
> in the patch description.

I sent v2 with more details in the commit message.

Thanks
Christophe