Subject: Re: [PATCH v4 20/28] wan: qmc_hdlc: Add runtime timeslots changes support

From: Herve Codina <[email-masked]>
Date: Thu, 24 Aug 2023 18:32:45 +0200

Hi Christophe,

On Mon, 21 Aug 2023 07:40:26 +0200
Christophe JAILLET <[email-masked]> wrote:

> Le 18/08/2023 à 18:39, Christophe Leroy a écrit :
> > From: Herve Codina <[email-masked]>
> > 
> > QMC channels support runtime timeslots changes but nothing is done at
> > the QMC HDLC driver to handle these changes.
> > 
> > Use existing IFACE ioctl in order to configure the timeslots to use.
> > 
> > Signed-off-by: Herve Codina <[email-masked]>
> > Reviewed-by: Christophe Leroy <[email-masked]>
> > Signed-off-by: Christophe Leroy <[email-masked]>
> > ---  
> 
> Hi,
> 
> a few nits below, should there be a v5.
> 
> >   drivers/net/wan/fsl_qmc_hdlc.c | 169 ++++++++++++++++++++++++++++++++-
> >   1 file changed, 168 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/wan/fsl_qmc_hdlc.c b/drivers/net/wan/fsl_qmc_hdlc.c
> > index 4f84ac5fc63e..4b8cb5761fd1 100644
> > --- a/drivers/net/wan/fsl_qmc_hdlc.c
> > +++ b/drivers/net/wan/fsl_qmc_hdlc.c
> > @@ -32,6 +32,7 @@ struct qmc_hdlc {
> >   	struct qmc_hdlc_desc tx_descs[8];
> >   	unsigned int tx_out;
> >   	struct qmc_hdlc_desc rx_descs[4];
> > +	u32 slot_map;
> >   };
> >   
> >   static inline struct qmc_hdlc *netdev_to_qmc_hdlc(struct net_device *netdev)
> > @@ -202,6 +203,162 @@ static netdev_tx_t qmc_hdlc_xmit(struct sk_buff *skb, struct net_device *netdev)
> >   	return NETDEV_TX_OK;
> >   }
> >   
> > +static int qmc_hdlc_xlate_slot_map(struct qmc_hdlc *qmc_hdlc,
> > +				   u32 slot_map, struct qmc_chan_ts_info *ts_info)
> > +{
> > +	u64 ts_mask_avail;
> > +	unsigned int bit;
> > +	unsigned int i;
> > +	u64 ts_mask;
> > +	u64 map = 0;  
> 
> This init looks useless.

Will be removed in the next iteration.

> 
> > +
> > +	/* Tx and Rx masks must be identical */
> > +	if (ts_info->rx_ts_mask_avail != ts_info->tx_ts_mask_avail) {
> > +		dev_err(qmc_hdlc->dev, "tx and rx available timeslots mismatch (0x%llx, 0x%llx)\n",
> > +			ts_info->rx_ts_mask_avail, ts_info->tx_ts_mask_avail);
> > +		return -EINVAL;
> > +	}
> > +
> > +	ts_mask_avail = ts_info->rx_ts_mask_avail;
> > +	ts_mask = 0;
> > +	map = slot_map;
> > +	bit = 0;
> > +	for (i = 0; i < 64; i++) {
> > +		if (ts_mask_avail & BIT_ULL(i)) {
> > +			if (map & BIT_ULL(bit))
> > +				ts_mask |= BIT_ULL(i);
> > +			bit++;
> > +		}
> > +	}
> > +
> > +	if (hweight64(ts_mask) != hweight64(map)) {
> > +		dev_err(qmc_hdlc->dev, "Cannot translate timeslots 0x%llx -> (0x%llx,0x%llx)\n",
> > +			map, ts_mask_avail, ts_mask);
> > +		return -EINVAL;
> > +	}
> > +
> > +	ts_info->tx_ts_mask = ts_mask;
> > +	ts_info->rx_ts_mask = ts_mask;
> > +	return 0;
> > +}
> > +
> > +static int qmc_hdlc_xlate_ts_info(struct qmc_hdlc *qmc_hdlc,
> > +				  const struct qmc_chan_ts_info *ts_info, u32 *slot_map)
> > +{
> > +	u64 ts_mask_avail;
> > +	unsigned int bit;
> > +	unsigned int i;
> > +	u64 ts_mask;
> > +	u64 map = 0;  
> 
> This init looks useless.

Will be remove in the next iteration.

> 
> > +
> > +	/* Tx and Rx masks must be identical */
> > +	if (ts_info->rx_ts_mask_avail != ts_info->tx_ts_mask_avail) {
> > +		dev_err(qmc_hdlc->dev, "tx and rx available timeslots mismatch (0x%llx, 0x%llx)\n",
> > +			ts_info->rx_ts_mask_avail, ts_info->tx_ts_mask_avail);
> > +		return -EINVAL;
> > +	}
> > +	if (ts_info->rx_ts_mask != ts_info->tx_ts_mask) {
> > +		dev_err(qmc_hdlc->dev, "tx and rx timeslots mismatch (0x%llx, 0x%llx)\n",
> > +			ts_info->rx_ts_mask, ts_info->tx_ts_mask);
> > +		return -EINVAL;
> > +	}
> > +
> > +	ts_mask_avail = ts_info->rx_ts_mask_avail;
> > +	ts_mask = ts_info->rx_ts_mask;
> > +	map = 0;
> > +	bit = 0;
> > +	for (i = 0; i < 64; i++) {
> > +		if (ts_mask_avail & BIT_ULL(i)) {
> > +			if (ts_mask & BIT_ULL(i))
> > +				map |= BIT_ULL(bit);
> > +			bit++;
> > +		}
> > +	}
> > +
> > +	if (hweight64(ts_mask) != hweight64(map)) {
> > +		dev_err(qmc_hdlc->dev, "Cannot translate timeslots (0x%llx,0x%llx) -> 0x%llx\n",
> > +			ts_mask_avail, ts_mask, map);
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (map >= BIT_ULL(32)) {
> > +		dev_err(qmc_hdlc->dev, "Slot map out of 32bit (0x%llx,0x%llx) -> 0x%llx\n",
> > +			ts_mask_avail, ts_mask, map);
> > +		return -EINVAL;
> > +	}
> > +
> > +	*slot_map = map;
> > +	return 0;
> > +}  
> 
> ...
> 
> > +static int qmc_hdlc_ioctl(struct net_device *netdev, struct if_settings *ifs)
> > +{
> > +	struct qmc_hdlc *qmc_hdlc = netdev_to_qmc_hdlc(netdev);
> > +	te1_settings te1;
> > +
> > +	switch (ifs->type) {
> > +	case IF_GET_IFACE:
> > +		ifs->type = IF_IFACE_E1;
> > +		if (ifs->size < sizeof(te1)) {
> > +			if (!ifs->size)
> > +				return 0; /* only type requested */
> > +
> > +			ifs->size = sizeof(te1); /* data size wanted */
> > +			return -ENOBUFS;
> > +		}
> > +
> > +		memset(&te1, 0, sizeof(te1));
> > +
> > +		/* Update slot_map */
> > +		te1.slot_map = qmc_hdlc->slot_map;
> > +
> > +		if (copy_to_user(ifs->ifs_ifsu.te1, &te1,  sizeof(te1)))  
> 
>                                                           ~~
> Extra space.

Will be fixed in the next iteration.

> 
> > +			return -EFAULT;
> > +		return 0;
> > +
> > +	case IF_IFACE_E1:
> > +	case IF_IFACE_T1:
> > +		if (!capable(CAP_NET_ADMIN))
> > +			return -EPERM;
> > +
> > +		if (netdev->flags & IFF_UP)
> > +			return -EBUSY;
> > +
> > +		if (copy_from_user(&te1, ifs->ifs_ifsu.te1, sizeof(te1)))
> > +			return -EFAULT;
> > +
> > +		return qmc_hdlc_set_iface(qmc_hdlc, ifs->type, &te1);
> > +
> > +	default:
> > +		return hdlc_ioctl(netdev, ifs);
> > +	}
> > +}  
> 
> ...
> 

Thanks for the review,
Best regards,
Hervé

-- 
Hervé Codina, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com