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Date:   Tue, 2 Mar 2021 11:50:52 +0100 (CET)
From:   Dario Binacchi <dariobin@libero.it>
To:     Marc Kleine-Budde <mkl@pengutronix.de>
Cc:     linux-kernel@vger.kernel.org,
        Federico Vaga <federico.vaga@gmail.com>,
        Alexander Stein <alexander.stein@systec-electronic.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Oliver Hartkopp <socketcan@hartkopp.net>,
        Vincent Mailhol <mailhol.vincent@wanadoo.fr>,
        Wolfgang Grandegger <wg@grandegger.com>,
        YueHaibing <yuehaibing@huawei.com>,
        Zhang Qilong <zhangqilong3@huawei.com>,
        linux-can@vger.kernel.org, netdev@vger.kernel.org
Message-ID: <1154674280.137227.1614682252245@mail1.libero.it>
In-Reply-To: <20210301194550.6zqmxzcwvzlgjzcj@pengutronix.de>
References: <20210228103856.4089-1-dariobin@libero.it>
 <20210228103856.4089-6-dariobin@libero.it>
 <20210301113805.jylhc373sip7zmed@pengutronix.de>
 <1037673059.602534.1614619302914@mail1.libero.it>
 <20210301194550.6zqmxzcwvzlgjzcj@pengutronix.de>
Subject: Re: [PATCH v3 5/6] can: c_can: prepare to up the message objects
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Hi Marc,

> Il 01/03/2021 20:45 Marc Kleine-Budde <mkl@pengutronix.de> ha scritto:
> 
>  
> On 01.03.2021 18:21:42, Dario Binacchi wrote:
> > > > @@ -730,7 +728,7 @@ static void c_can_do_tx(struct net_device *dev)
> > > >  	while ((idx = ffs(pend))) {
> > > >  		idx--;
> > > >  		pend &= ~(1 << idx);
> > > > -		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
> > > > +		obj = idx + priv->msg_obj_tx_first;
> > > >  		c_can_inval_tx_object(dev, IF_TX, obj);
> > > >  		can_get_echo_skb(dev, idx, NULL);
> > > >  		bytes += priv->dlc[idx];
> > > > @@ -740,7 +738,7 @@ static void c_can_do_tx(struct net_device *dev)
> > > >  	/* Clear the bits in the tx_active mask */
> > > >  	atomic_sub(clr, &priv->tx_active);
> > > >  
> > > > -	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))
> > > > +	if (clr & (1 << (priv->msg_obj_tx_num - 1)))
> > > 
> > > Do we need 1UL here, too?
> > 
> > Do you agree if I use the BIT macro ?
> 
> No, please use GENMASK(priv->msg_obj_tx_num, 0) here.
> 

In case of 64 message objects, msg_obj_tx_num = 32, and 1 << (priv->msg_obj_tx_num - 1) = 0x80000000. 
GENMASK(priv->msg_obj_tx_num, 0) = 0. 
BIT(priv->msg_obj_tx_num - 1) = 0x80000000.

Thanks and regards,
Dario

> regrads,
> Marc
> 
> -- 
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