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, 22 Feb 2022 10:40:24 -0800 [thread overview]
Message-ID: <947eb9a4-683e-7d10-d15c-28e2f18d192d@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.
...
>> + bat_req->bat_mask[idx] = 1;
> ...
>> + if (!bat_req->bat_mask[index])
> ...
>> + bat->bat_mask[index] = 0;
> Seem to be linux/bitmap.h
>
> I wonder though if the loop in t7xx_dpmaif_avail_pkt_bat_cnt()
> could be replaced with arithmetic calculation based on
> bat_release_rd_idx and some other idx? It would make the bitmap
> unnecessary.
A bitmap is needed since entries could be returned out of order.
...
>> + hw_read_idx = t7xx_dpmaif_ul_get_rd_idx(&dpmaif_ctrl->hif_hw_info, q_num);
>> +
>> + new_hw_rd_idx = hw_read_idx / DPMAIF_UL_DRB_ENTRY_WORD;
> Is DPMAIF_UL_DRB_ENTRY_WORD size of an entry? In that case it
> would probably make sense put it inside t7xx_dpmaif_ul_get_rd_idx?
Yes, moving this into t7xx_dpmaif_ul_get_rd_idx()
>> + if (new_hw_rd_idx >= DPMAIF_DRB_ENTRY_SIZE) {
> Is DPMAIF_DRB_ENTRY_SIZE telling the number of entries rather than
> an "ENTRY_SIZE"? I think these both constant could likely be named
> better.
...
>> +static int t7xx_txq_burst_send_skb(struct dpmaif_tx_queue *txq)
>> +{
>> + int drb_remain_cnt, i;
>> + unsigned long flags;
>> + int drb_cnt = 0;
>> + int ret = 0;
>> +
>> + spin_lock_irqsave(&txq->tx_lock, flags);
>> + drb_remain_cnt = t7xx_ring_buf_rd_wr_count(txq->drb_size_cnt, txq->drb_release_rd_idx,
>> + txq->drb_wr_idx, DPMAIF_WRITE);
>> + spin_unlock_irqrestore(&txq->tx_lock, flags);
>> +
>> + for (i = 0; i < DPMAIF_SKB_TX_BURST_CNT; i++) {
>> + struct sk_buff *skb;
>> +
>> + spin_lock_irqsave(&txq->tx_skb_lock, flags);
>> + skb = list_first_entry_or_null(&txq->tx_skb_queue, struct sk_buff, list);
>> + spin_unlock_irqrestore(&txq->tx_skb_lock, flags);
>> +
>> + if (!skb)
>> + break;
>> +
>> + if (drb_remain_cnt < skb->cb[TX_CB_DRB_CNT]) {
>> + spin_lock_irqsave(&txq->tx_lock, flags);
>> + drb_remain_cnt = t7xx_ring_buf_rd_wr_count(txq->drb_size_cnt,
>> + txq->drb_release_rd_idx,
>> + txq->drb_wr_idx, DPMAIF_WRITE);
>> + spin_unlock_irqrestore(&txq->tx_lock, flags);
>> + continue;
>> + }
> ...
>> + if (drb_cnt > 0) {
>> + txq->drb_lack = false;
>> + ret = drb_cnt;
>> + } else if (ret == -ENOMEM) {
>> + txq->drb_lack = true;
> Based on the variable name, I'd expect drb_lack be set true when
> drb_remain_cnt < skb->cb[TX_CB_DRB_CNT] occurred but that doesn't
> happen. Maybe that if branch within loop should set ret = -ENOMEM;
> before continue?
This drb_lack logic is going to be dropped since it was intended for
multiple Tx queues but currently only one is used.
> It would be nice if the drb check here and in
> t7xx_check_tx_queue_drb_available could be consolidated into
> a single place. That requires small refactoring (adding __
> variant of that function which does just the check).
>
> Please also check the other comments on skb->cb below.
...
>
>> +int t7xx_dpmaif_tx_send_skb(struct dpmaif_ctrl *dpmaif_ctrl, unsigned int txqt, struct sk_buff *skb)
>> +{
>> + bool tx_drb_available = true;
> ...
>> + send_drb_cnt = t7xx_get_drb_cnt_per_skb(skb);
>> +
>> + txq = &dpmaif_ctrl->txq[txqt];
>> + if (!(txq->tx_skb_stat++ % DPMAIF_SKB_TX_BURST_CNT))
>> + tx_drb_available = t7xx_check_tx_queue_drb_available(txq, send_drb_cnt);
>> +
>> + if (!tx_drb_available || txq->tx_submit_skb_cnt >= txq->tx_list_max_len) {
> Because of the modulo if, drbs might not be available despite
> variable claims them to be. Is it intentional?
It is intentional, I'll refactor this to do the DRB and tx_list_max_len
checks independently for clarity.
...
next prev parent reply other threads:[~2022-02-22 18:40 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
2022-02-16 14:36 ` Ilpo Järvinen
2022-02-22 18:40 ` Martinez, Ricardo [this message]
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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