[PATCH] net: ethernet: mediatek: Fix overlapping capability bits.

[PATCH] net: ethernet: mediatek: Fix overlapping capability bits.

[René van Dorst]

Both MTK_TRGMII_MT7621_CLK and MTK_PATH_BIT are defined as bit 10.

This causes issues on non-MT7621 devices which has the
MTK_PATH_BIT(MTK_ETH_PATH_GMAC1_RGMII) capability set.
The wrong TRGMII setup code is executed.

Moving the MTK_PATH_BIT to bit 11 fixes the issue.

Fixes: 8efaa653a8a5 ("net: ethernet: mediatek: Add MT7621 TRGMII mode
support")
Signed-off-by: René van Dorst <opensource@vdorst.com>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index 876ce6798709..2cb8a915731c 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -626,7 +626,7 @@ enum mtk_eth_path {
 #define MTK_TRGMII_MT7621_CLK		BIT(10)
 
 /* Supported path present on SoCs */
-#define MTK_PATH_BIT(x)         BIT((x) + 10)
+#define MTK_PATH_BIT(x)         BIT((x) + 11)
 
 #define MTK_GMAC1_RGMII \
 	(MTK_PATH_BIT(MTK_ETH_PATH_GMAC1_RGMII) | MTK_RGMII)
-- 
2.20.1

Re: [PATCH] net: ethernet: mediatek: Fix overlapping capability bits.

[Willem de Bruijn]

On Sat, Jun 29, 2019 at 8:24 AM René van Dorst <opensource@vdorst.com> wrote:
>
> Both MTK_TRGMII_MT7621_CLK and MTK_PATH_BIT are defined as bit 10.
>
> This causes issues on non-MT7621 devices which has the
> MTK_PATH_BIT(MTK_ETH_PATH_GMAC1_RGMII) capability set.
> The wrong TRGMII setup code is executed.
>
> Moving the MTK_PATH_BIT to bit 11 fixes the issue.
>
> Fixes: 8efaa653a8a5 ("net: ethernet: mediatek: Add MT7621 TRGMII mode
> support")
> Signed-off-by: René van Dorst <opensource@vdorst.com>

This targets net? Please mark networking patches [PATCH net] or [PATCH
net-next].

> ---
>  drivers/net/ethernet/mediatek/mtk_eth_soc.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> index 876ce6798709..2cb8a915731c 100644
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> @@ -626,7 +626,7 @@ enum mtk_eth_path {
>  #define MTK_TRGMII_MT7621_CLK          BIT(10)
>
>  /* Supported path present on SoCs */
> -#define MTK_PATH_BIT(x)         BIT((x) + 10)
>
> +#define MTK_PATH_BIT(x)         BIT((x) + 11)
>

To avoid this happening again, perhaps make the reserved range more explicit?

For instance

#define MTK_FIXED_BIT_LAST 10
#define MTK_TRGMII_MT7621_CLK  BIT(MTK_FIXED_BIT_LAST)

#define MTK_PATH_BIT_FIRST  (MTK_FIXED_BIT_LAST + 1)
#define MTK_PATH_BIT_LAST (MTK_FIXED_BIT_LAST + 7)
#define MTK_MUX_BIT_FIRST (MTK_PATH_BIT_LAST + 1)

Though I imagine there are cleaner approaches. Perhaps define all
fields as enum instead of just mtk_eth_mux and mtk_eth_path. Then
there can be no accidental collision.

Re: [PATCH] net: ethernet: mediatek: Fix overlapping capability bits.

[René van Dorst]

Quoting Willem de Bruijn <willemdebruijn.kernel@gmail.com>:

> On Sat, Jun 29, 2019 at 8:24 AM René van Dorst <opensource@vdorst.com> wrote:
>>
>> Both MTK_TRGMII_MT7621_CLK and MTK_PATH_BIT are defined as bit 10.
>>
>> This causes issues on non-MT7621 devices which has the
>> MTK_PATH_BIT(MTK_ETH_PATH_GMAC1_RGMII) capability set.
>> The wrong TRGMII setup code is executed.
>>
>> Moving the MTK_PATH_BIT to bit 11 fixes the issue.
>>
>> Fixes: 8efaa653a8a5 ("net: ethernet: mediatek: Add MT7621 TRGMII mode
>> support")
>> Signed-off-by: René van Dorst <opensource@vdorst.com>
>
> This targets net? Please mark networking patches [PATCH net] or [PATCH
> net-next].

Hi Willem,

Thanks for you input.

This patch was for net-next.

>
>> ---
>>  drivers/net/ethernet/mediatek/mtk_eth_soc.h | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h  
>> b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
>> index 876ce6798709..2cb8a915731c 100644
>> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
>> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
>> @@ -626,7 +626,7 @@ enum mtk_eth_path {
>>  #define MTK_TRGMII_MT7621_CLK          BIT(10)
>>
>>  /* Supported path present on SoCs */
>> -#define MTK_PATH_BIT(x)         BIT((x) + 10)
>>
>> +#define MTK_PATH_BIT(x)         BIT((x) + 11)
>>
>
> To avoid this happening again, perhaps make the reserved range more explicit?
>
> For instance
>
> #define MTK_FIXED_BIT_LAST 10
> #define MTK_TRGMII_MT7621_CLK  BIT(MTK_FIXED_BIT_LAST)
>
> #define MTK_PATH_BIT_FIRST  (MTK_FIXED_BIT_LAST + 1)
> #define MTK_PATH_BIT_LAST (MTK_FIXED_BIT_LAST + 7)
> #define MTK_MUX_BIT_FIRST (MTK_PATH_BIT_LAST + 1)
>
> Though I imagine there are cleaner approaches. Perhaps define all
> fields as enum instead of just mtk_eth_mux and mtk_eth_path. Then
> there can be no accidental collision.

You mean in a similar way as done in the ethtool.h [0]?

Use a enum to define the unique bits.

enum mtk_bits {
	MTK_RGMII_BIT = 0,
	MTK_SGMII_BIT,
	MTK_TRGMII_BIT,
	AND SO ON ....
};

Also move the mtk_eth_mux and mtk_eth_path in to this enum.

Then use defines to convert bits to values.

#define MTK_RGMII  BIT(MTK_RGMII_BIT)
#define MTK_TRGMII BIT(MTK_TRGMII_BIT)

Replace the MTK_PATH_BIT and MTK_PATH_BIT macro with BIT()

Is this what you had in mind?

Greats,

René

[0]:  
https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/ethtool.h#L1402

Re: [PATCH] net: ethernet: mediatek: Fix overlapping capability bits.

[Willem de Bruijn]

On Mon, Jul 1, 2019 at 8:44 AM René van Dorst <opensource@vdorst.com> wrote:
>
> Quoting Willem de Bruijn <willemdebruijn.kernel@gmail.com>:
>
> > On Sat, Jun 29, 2019 at 8:24 AM René van Dorst <opensource@vdorst.com> wrote:
> >>
> >> Both MTK_TRGMII_MT7621_CLK and MTK_PATH_BIT are defined as bit 10.
> >>
> >> This causes issues on non-MT7621 devices which has the
> >> MTK_PATH_BIT(MTK_ETH_PATH_GMAC1_RGMII) capability set.
> >> The wrong TRGMII setup code is executed.
> >>
> >> Moving the MTK_PATH_BIT to bit 11 fixes the issue.
> >>
> >> Fixes: 8efaa653a8a5 ("net: ethernet: mediatek: Add MT7621 TRGMII mode
> >> support")
> >> Signed-off-by: René van Dorst <opensource@vdorst.com>
> >
> > This targets net? Please mark networking patches [PATCH net] or [PATCH
> > net-next].
>
> Hi Willem,
>
> Thanks for you input.
>
> This patch was for net-next.
>
> >
> >> ---
> >>  drivers/net/ethernet/mediatek/mtk_eth_soc.h | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> >> b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> >> index 876ce6798709..2cb8a915731c 100644
> >> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> >> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> >> @@ -626,7 +626,7 @@ enum mtk_eth_path {
> >>  #define MTK_TRGMII_MT7621_CLK          BIT(10)
> >>
> >>  /* Supported path present on SoCs */
> >> -#define MTK_PATH_BIT(x)         BIT((x) + 10)
> >>
> >> +#define MTK_PATH_BIT(x)         BIT((x) + 11)
> >>
> >
> > To avoid this happening again, perhaps make the reserved range more explicit?
> >
> > For instance
> >
> > #define MTK_FIXED_BIT_LAST 10
> > #define MTK_TRGMII_MT7621_CLK  BIT(MTK_FIXED_BIT_LAST)
> >
> > #define MTK_PATH_BIT_FIRST  (MTK_FIXED_BIT_LAST + 1)
> > #define MTK_PATH_BIT_LAST (MTK_FIXED_BIT_LAST + 7)
> > #define MTK_MUX_BIT_FIRST (MTK_PATH_BIT_LAST + 1)
> >
> > Though I imagine there are cleaner approaches. Perhaps define all
> > fields as enum instead of just mtk_eth_mux and mtk_eth_path. Then
> > there can be no accidental collision.
>
> You mean in a similar way as done in the ethtool.h [0]?
>
> Use a enum to define the unique bits.
>
> enum mtk_bits {
>         MTK_RGMII_BIT = 0,
>         MTK_SGMII_BIT,
>         MTK_TRGMII_BIT,
>         AND SO ON ....
> };
>
> Also move the mtk_eth_mux and mtk_eth_path in to this enum.

That's the key part: they are all part of the same namespace and these
enums are not used anywhere else, so a single enum will avoid
accidentally namespace collisions.

> Then use defines to convert bits to values.
>
> #define MTK_RGMII  BIT(MTK_RGMII_BIT)
> #define MTK_TRGMII BIT(MTK_TRGMII_BIT)
>
> Replace the MTK_PATH_BIT and MTK_PATH_BIT macro with BIT()
>
> Is this what you had in mind?

Great find. Exactly, but I did not find such a clear example.

>
> Greats,
>
> René
>
> [0]:
> https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/ethtool.h#L1402
>
>
>