Re: [PATCH net-next v7 5/6] stmmac: dwmac-mediatek: add support for mt8195

Biao Huang
2021-12-09T01:50:09Z

Dear Jakub,

Sorry for some typo in previous reply, fix it here.

All these warning lines share a similar semantics:
delay_val |= FIELD_PREP(xxx, !!val);

and, should come from the expansion of FIELD_PREP in
include/linux/bitfiled.h:

FIELD _PREP --> __BF_FILED_CHECK --> "~((_mask) >> __bf_shf(_mask)) &
(_val) : 0,"

===============================================================
__BF_FILED_CHECK {
...
BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \
~((_mask) >> __bf_shf(_mask)) & (_val) : 0, \
_pfx "value too large for the field"); \ ...
===============================================================

Should I fix it by converting
delay_val |= FIELD_PREP(ETH_DLY_TXC_ENABLE, !!mac_delay->tx_delay);
to
en_val = !!mac_delay->tx_delay;
delay_val |= FIELD_PREP(ETH_DLY_TXC_ENABLE, en_val);

or other suggestions for these warnings?

Thanks~
On Wed, 2021-12-08 at 06:38 -0800, Jakub Kicinski wrote:
> On Wed, 8 Dec 2021 13:47:15 +0800 Biao Huang wrote:
> > Add Ethernet support for MediaTek SoCs from the mt8195 family.
> >
> > Signed-off-by: Biao Huang <biao.huang@mediatek.com>
> > Acked-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno@collabora.com>
>
> sparse reports whole bunch of warnings like this:
>
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:213:30: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:217:30: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:228:38: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:232:38: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:247:46: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:255:46: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:273:30: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:277:30: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:375:30: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:379:30: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:390:43: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:397:43: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:415:46: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:426:46: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:439:35: warning:
> dubious: x & !y
> drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c:443:30: warning:
> dubious: x & !y
>
> Any idea on where these come from?