From: "Martinez, Ricardo" <ricardo.martinez@linux.intel.com>
To: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Cc: Netdev <netdev@vger.kernel.org>,
linux-wireless@vger.kernel.org, kuba@kernel.org,
davem@davemloft.net, johannes@sipsolutions.net,
ryazanov.s.a@gmail.com, loic.poulain@linaro.org,
m.chetan.kumar@intel.com, chandrashekar.devegowda@intel.com,
linuxwwan@intel.com, chiranjeevi.rapolu@linux.intel.com,
haijun.liu@mediatek.com, amir.hanania@intel.com,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
dinesh.sharma@intel.com, eliot.lee@intel.com,
moises.veleta@intel.com, pierre-louis.bossart@intel.com,
muralidharan.sethuraman@intel.com,
Soumya.Prakash.Mishra@intel.com, sreehari.kancharla@intel.com
Subject: Re: [PATCH net-next v4 08/13] net: wwan: t7xx: Add data path interface
Date: Tue, 15 Feb 2022 18:17:53 -0800 [thread overview]
Message-ID: <05b6a2dd-f485-ce4a-d508-e90f9304d016@linux.intel.com> (raw)
In-Reply-To: <ca592f64-c581-56a8-8d90-5341ebd8932d@linux.intel.com>
On 2/8/2022 12:19 AM, Ilpo Järvinen wrote:
> On Thu, 13 Jan 2022, Ricardo Martinez wrote:
>
>> From: Haijun Liu <haijun.liu@mediatek.com>
>>
>> Data Path Modem AP Interface (DPMAIF) HIF layer provides methods
>> for initialization, ISR, control and event handling of TX/RX flows.
...
>
>> + spin_lock_irqsave(&txq->tx_lock, flags);
>> + cur_idx = txq->drb_wr_idx;
>> + drb_wr_idx_backup = cur_idx;
>> +
>> + txq->drb_wr_idx += send_cnt;
>> + if (txq->drb_wr_idx >= txq->drb_size_cnt)
>> + txq->drb_wr_idx -= txq->drb_size_cnt;
>> +
>> + t7xx_setup_msg_drb(dpmaif_ctrl, txq->index, cur_idx, skb->len, 0, skb->cb[TX_CB_NETIF_IDX]);
>> + t7xx_record_drb_skb(dpmaif_ctrl, txq->index, cur_idx, skb, 1, 0, 0, 0, 0);
>> + spin_unlock_irqrestore(&txq->tx_lock, flags);
>> +
>> + cur_idx = t7xx_ring_buf_get_next_wr_idx(txq->drb_size_cnt, cur_idx);
>> +
>> + for (wr_cnt = 0; wr_cnt < payload_cnt; wr_cnt++) {
>> + if (!wr_cnt) {
>> + data_len = skb_headlen(skb);
>> + data_addr = skb->data;
>> + is_frag = false;
>> + } else {
>> + skb_frag_t *frag = info->frags + wr_cnt - 1;
>> +
>> + data_len = skb_frag_size(frag);
>> + data_addr = skb_frag_address(frag);
>> + is_frag = true;
>> + }
>> +
>> + if (wr_cnt == payload_cnt - 1)
>> + is_last_one = true;
>> +
>> + /* TX mapping */
>> + bus_addr = dma_map_single(dpmaif_ctrl->dev, data_addr, data_len, DMA_TO_DEVICE);
>> + if (dma_mapping_error(dpmaif_ctrl->dev, bus_addr)) {
>> + dev_err(dpmaif_ctrl->dev, "DMA mapping fail\n");
>> + atomic_set(&txq->tx_processing, 0);
>> +
>> + spin_lock_irqsave(&txq->tx_lock, flags);
>> + txq->drb_wr_idx = drb_wr_idx_backup;
>> + spin_unlock_irqrestore(&txq->tx_lock, flags);
> Hmm, can txq's drb_wr_idx get updated (or cleared) by something else
> in between these critical sections?
drb_wr_idx cannot be modified inbetween, but it can be used to calculate
the number of DRBs available, which shouldn't be a problem.
The function is reserving the DRBs at the beginning, in the rare case of
error it will release them.
...
> + txq_id = t7xx_select_tx_queue(dpmaif_ctrl);
> + if (txq_id >= 0) {
> t7xx_select_tx_queue used to do que_started check (in v2) but it
> doesn't anymore so this if is always true these days. I'm left to
> wonder though if it was ok to drop that que_started check?
The que_started check wasn't supposed to be dropped, I'll add it back.
...
>> +/* SKB control buffer indexed values */
>> +#define TX_CB_NETIF_IDX 0
>> +#define TX_CB_QTYPE 1
>> +#define TX_CB_DRB_CNT 2
> The normal way of storing a struct to skb->cb area is:
>
> struct t7xx_skb_cb {
> u8 netif_idx;
> u8 qtype;
> u8 drb_cnt;
> };
>
> #define T7XX_SKB_CB(__skb) ((struct t7xx_skb_cb *)&((__skb)->cb[0]))
>
> However, there's only a single txqt/qtype (TXQ_TYPE_DEFAULT) in the
> patchset? And it seems to me that drb_cnt is a value that could be always
> derived using t7xx_get_drb_cnt_per_skb() from the skb rather than
> stored?
The next iteration will contain t7xx_tx_skb_cb and t7xx_rx_skb_cb
structures.
Also, q_number is going to be used instead of qtype.
Only one queue is used but I think we can keep this code generic as it
is straight forward (not like the drb_lack case), any thoughts?
>> +#define DRB_PD_DATA_LEN ((u32)GENMASK(31, 16))
> Drop the cast?
The cast was added to avoid a compiler warning about truncated bits.
I'll move it to the place where it is required:
drb->header &= cpu_to_le32(~(u32)DRB_PD_DATA_LEN);
...
next prev parent reply other threads:[~2022-02-16 2:17 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-14 1:06 [PATCH net-next v4 00/13] net: wwan: t7xx: PCIe driver for MediaTek M.2 modem Ricardo Martinez
2022-01-14 1:06 ` [PATCH net-next v4 01/13] list: Add list_next_entry_circular() and list_prev_entry_circular() Ricardo Martinez
2022-01-14 13:42 ` Andy Shevchenko
2022-01-14 1:06 ` [PATCH net-next v4 02/13] net: wwan: t7xx: Add control DMA interface Ricardo Martinez
2022-01-14 14:13 ` Andy Shevchenko
2022-01-18 14:13 ` Ilpo Järvinen
2022-01-18 22:22 ` Martinez, Ricardo
2022-01-19 9:52 ` Ilpo Järvinen
2022-01-19 19:04 ` Martinez, Ricardo
2022-02-11 0:25 ` Sergey Ryazanov
2022-02-16 2:24 ` Martinez, Ricardo
2022-02-10 13:50 ` Ilpo Järvinen
2022-01-14 1:06 ` [PATCH net-next v4 03/13] net: wwan: t7xx: Add core components Ricardo Martinez
2022-01-16 15:37 ` kernel test robot
2022-01-24 14:51 ` Ilpo Järvinen
2022-01-25 19:13 ` Martinez, Ricardo
2022-01-26 10:45 ` Ilpo Järvinen
2022-01-27 17:36 ` Ilpo Järvinen
2022-01-14 1:06 ` [PATCH net-next v4 04/13] net: wwan: t7xx: Add port proxy infrastructure Ricardo Martinez
2022-01-25 13:38 ` Ilpo Järvinen
2022-02-10 13:34 ` Ilpo Järvinen
2022-01-14 1:06 ` [PATCH net-next v4 05/13] net: wwan: t7xx: Add control port Ricardo Martinez
2022-01-27 10:40 ` Ilpo Järvinen
2022-01-27 14:53 ` Andy Shevchenko
2022-01-14 1:06 ` [PATCH net-next v4 06/13] net: wwan: t7xx: Add AT and MBIM WWAN ports Ricardo Martinez
2022-01-27 11:56 ` Ilpo Järvinen
2022-01-14 1:06 ` [PATCH net-next v4 07/13] net: wwan: t7xx: Data path HW layer Ricardo Martinez
2022-02-01 9:08 ` Ilpo Järvinen
2022-02-01 10:13 ` Ilpo Järvinen
2022-02-03 2:30 ` Martinez, Ricardo
2022-01-14 1:06 ` [PATCH net-next v4 08/13] net: wwan: t7xx: Add data path interface Ricardo Martinez
2022-02-03 14:23 ` Ilpo Järvinen
2022-02-08 8:19 ` Ilpo Järvinen
2022-02-16 2:17 ` Martinez, Ricardo [this message]
2022-02-16 14:36 ` Ilpo Järvinen
2022-02-22 18:40 ` Martinez, Ricardo
2022-01-14 1:06 ` [PATCH net-next v4 09/13] net: wwan: t7xx: Add WWAN network interface Ricardo Martinez
2022-02-10 10:45 ` Ilpo Järvinen
2022-01-14 1:06 ` [PATCH net-next v4 10/13] net: wwan: t7xx: Introduce power management support Ricardo Martinez
2022-02-10 10:58 ` Ilpo Järvinen
2022-01-14 1:06 ` [PATCH net-next v4 11/13] net: wwan: t7xx: Runtime PM Ricardo Martinez
2022-01-14 1:06 ` [PATCH net-next v4 12/13] net: wwan: t7xx: Device deep sleep lock/unlock Ricardo Martinez
2022-01-14 1:06 ` [PATCH net-next v4 13/13] net: wwan: t7xx: Add maintainers and documentation Ricardo Martinez
2022-01-15 14:53 ` [PATCH net-next v4 00/13] net: wwan: t7xx: PCIe driver for MediaTek M.2 modem Loic Poulain
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