* [PATCH/RFC] usb: gadget: CONFIG_USB_S3C_HSOTG should depend on HAS_DMA
@ 2014-05-06 12:49 Geert Uytterhoeven
2014-05-06 13:17 ` David Laight
0 siblings, 1 reply; 3+ messages in thread
From: Geert Uytterhoeven @ 2014-05-06 12:49 UTC (permalink / raw)
To: Felipe Balbi, Greg Kroah-Hartman, Ben Dooks
Cc: linux-usb, linux-kernel, Geert Uytterhoeven
If NO_DMA=y:
drivers/built-in.o: In function `s3c_hsotg_map_dma':
s3c-hsotg.c:(.text+0x375b2c): undefined reference to `usb_gadget_map_request'
drivers/built-in.o: In function `s3c_hsotg_unmap_dma':
s3c-hsotg.c:(.text+0x376a32): undefined reference to `usb_gadget_unmap_request'
make[3]: *** [vmlinux] Error 1
Note that all callers of s3c_hsotg_map_dma()/s3c_hsotg_unmap_dma() are
protected by a call into the using_dma() checking function:
static inline bool using_dma(struct s3c_hsotg *hsotg)
{
return false; /* support is not complete */
}
but not all versions of gcc manage to optimize the check away, causing a
link error.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
Perhaps the DMA code should be removed completely, as its unused, or be
protected by #ifdef CONFIG_HAS_DMA instead?
drivers/usb/gadget/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 3557c7e5040d..0e9dead51a27 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -302,6 +302,7 @@ config USB_PXA27X
config USB_S3C_HSOTG
tristate "Designware/S3C HS/OtG USB Device controller"
+ depends on HAS_DMA
help
The Designware USB2.0 high-speed gadget controller
integrated into many SoCs.
--
1.7.9.5
^ permalink raw reply related [flat|nested] 3+ messages in thread
* RE: [PATCH/RFC] usb: gadget: CONFIG_USB_S3C_HSOTG should depend on HAS_DMA
2014-05-06 12:49 [PATCH/RFC] usb: gadget: CONFIG_USB_S3C_HSOTG should depend on HAS_DMA Geert Uytterhoeven
@ 2014-05-06 13:17 ` David Laight
2014-05-06 15:02 ` Geert Uytterhoeven
0 siblings, 1 reply; 3+ messages in thread
From: David Laight @ 2014-05-06 13:17 UTC (permalink / raw)
To: 'Geert Uytterhoeven',
Felipe Balbi, Greg Kroah-Hartman, Ben Dooks
Cc: linux-usb, linux-kernel
From: Geert Uytterhoeven
> If NO_DMA=y:
>
> drivers/built-in.o: In function `s3c_hsotg_map_dma':
> s3c-hsotg.c:(.text+0x375b2c): undefined reference to `usb_gadget_map_request'
> drivers/built-in.o: In function `s3c_hsotg_unmap_dma':
> s3c-hsotg.c:(.text+0x376a32): undefined reference to `usb_gadget_unmap_request'
> make[3]: *** [vmlinux] Error 1
>
> Note that all callers of s3c_hsotg_map_dma()/s3c_hsotg_unmap_dma() are
> protected by a call into the using_dma() checking function:
>
> static inline bool using_dma(struct s3c_hsotg *hsotg)
> {
> return false; /* support is not complete */
> }
>
> but not all versions of gcc manage to optimize the check away, causing a
> link error.
A have seen gcc optimise away a call, but leave the undefined symbol
in the symbol table.
That might be what is happening here.
I don't know a generic solution, I used 'objcopy -N__udivdi3' to remove
the explicit unwanted reference from my driver.
David
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH/RFC] usb: gadget: CONFIG_USB_S3C_HSOTG should depend on HAS_DMA
2014-05-06 13:17 ` David Laight
@ 2014-05-06 15:02 ` Geert Uytterhoeven
0 siblings, 0 replies; 3+ messages in thread
From: Geert Uytterhoeven @ 2014-05-06 15:02 UTC (permalink / raw)
To: David Laight
Cc: Felipe Balbi, Greg Kroah-Hartman, Ben Dooks, linux-usb, linux-kernel
Hi David,
On Tue, May 6, 2014 at 3:17 PM, David Laight <David.Laight@aculab.com> wrote:
>> If NO_DMA=y:
>>
>> drivers/built-in.o: In function `s3c_hsotg_map_dma':
>> s3c-hsotg.c:(.text+0x375b2c): undefined reference to `usb_gadget_map_request'
>> drivers/built-in.o: In function `s3c_hsotg_unmap_dma':
>> s3c-hsotg.c:(.text+0x376a32): undefined reference to `usb_gadget_unmap_request'
>> make[3]: *** [vmlinux] Error 1
>>
>> Note that all callers of s3c_hsotg_map_dma()/s3c_hsotg_unmap_dma() are
>> protected by a call into the using_dma() checking function:
>>
>> static inline bool using_dma(struct s3c_hsotg *hsotg)
>> {
>> return false; /* support is not complete */
>> }
>>
>> but not all versions of gcc manage to optimize the check away, causing a
>> link error.
>
> A have seen gcc optimise away a call, but leave the undefined symbol
> in the symbol table.
> That might be what is happening here.
Indeed, the unused functions s3c_hsotg_{,un}map_dma() are still there,
but the calls to them have been optimized away.
Marking s3c_hsotg_{,un}map_dma() inline fixes that. I'll send a new patch
doing that, as it's a bit silly to require "depends on HAS_DMA" for a driver
which has DMA disabled.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-05-06 12:49 [PATCH/RFC] usb: gadget: CONFIG_USB_S3C_HSOTG should depend on HAS_DMA Geert Uytterhoeven
2014-05-06 13:17 ` David Laight
2014-05-06 15:02 ` Geert Uytterhoeven
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