Re: [net-next v9 5/6] net: stmmac: Add glue layer for StarFive JH7110 SoC
From: Jakub Kicinski <kuba@xxxxxxxxxx>
to: Samin Guo <samin.guo@xxxxxxxxxxxxxxxx>
data: 2023/3/29
> On Tue, 28 Mar 2023 14:20:08 +0800 Samin Guo wrote:
>> This adds StarFive dwmac driver support on the StarFive JH7110 SoC.
>>
>> Tested-by: Tommaso Merciai <tomm.merciai@xxxxxxxxx>
>> Co-developed-by: Emil Renner Berthing <kernel@xxxxxxxx>
>> Signed-off-by: Emil Renner Berthing <kernel@xxxxxxxx>
>> Signed-off-by: Samin Guo <samin.guo@xxxxxxxxxxxxxxxx>
>
> Excellent, now it applies cleanly :)
>
> Our clang build with W=1 complains that:
>
> drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c:37:2: warning: variable 'rate' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized]
> default:
> ^~~~~~~
> drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c:42:36: note: uninitialized use occurs here
> err = clk_set_rate(dwmac->clk_tx, rate);
> ^~~~
> drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c:24:20: note: initialize the variable 'rate' to silence this warning
> unsigned long rate;
> ^
> = 0
>
>
> not sure how you prefer to fix this. Maybe return early?
Hi Jakub,
Sorry, gcc I used does not report this error (:, and clang compile checks are more stringent.
Also, if return early at default node, Arun Ramadoss doesn't think it's a good idea because the function is a void type.
I think I can initialize the value of rate first by clk_get_rate (Intel did the same <dwmac-intel-plat.c: kmb_eth_fix_mac_speed >),
like this:
static void starfive_dwmac_fix_mac_speed(void *priv, unsigned int speed)
{
struct starfive_dwmac *dwmac = priv;
unsigned long rate;
int err;
rate = clk_get_rate(dwmac->tx_clk);
switch (speed) {
case SPEED_1000:
rate = 125000000;
break;
case SPEED_100:
rate = 25000000;
break;
case SPEED_10:
rate = 2500000;
break;
default:
dev_err(dwmac->dev, "invalid speed %u\n", speed);
break;
}
err = clk_set_rate(dwmac->clk_tx, rate);
if (err)
dev_err(dwmac->dev, "failed to set tx rate %lu\n", rate);
}
What do you think?
Best regards,
Samin
