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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 02/13] net: wwan: t7xx: Add control DMA interface
Date: Tue, 18 Jan 2022 14:22:08 -0800	[thread overview]
Message-ID: <4a4b2848-d665-c9ba-c66a-dd4408e94ea5@linux.intel.com> (raw)
In-Reply-To: <d5854453-84b-1eba-7cc7-d94f41a185d@linux.intel.com>


On 1/18/2022 6:13 AM, Ilpo Järvinen wrote:
> On Thu, 13 Jan 2022, Ricardo Martinez wrote:
...
>> +#define CLDMA_NUM 2
> I tried to understand its purpose but it seems that only one of the
> indexes is used in the arrays where this define gives the size? Related to
> this, ID_CLDMA0 is not used anywhere?

The modem HW has 2 CLDMAs, idx 0 for the app processor (SAP) and idx 1 
for the modem (MD).

CLDMA_NUM is defined as 2 to reflect the HW capabilities but mainly to 
have a cleaner upcoming

patches, which will use ID_CLDMA0.

If having array's of size 1 is not a problem then we can define 
CLDMA_NUM as 1 and

play with the CLDMA indexes.

...


>> +static void t7xx_cldma_enable_irq(struct cldma_ctrl *md_ctrl)
>> +{
>> +	t7xx_pcie_mac_set_int(md_ctrl->t7xx_dev, md_ctrl->hw_info.phy_interrupt_id);
>> +}
>> +
>> +static void t7xx_cldma_disable_irq(struct cldma_ctrl *md_ctrl)
>> +{
>> +	t7xx_pcie_mac_clear_int(md_ctrl->t7xx_dev, md_ctrl->hw_info.phy_interrupt_id);
>> +}
> t7xx_pcie_mac_set_int and t7xx_pcie_mac_clear_int are only defined
> by a later patch.
>
>> +static bool t7xx_cldma_qs_are_active(struct t7xx_cldma_hw *hw_info)
>> +{
>> +	unsigned int tx_active;
>> +	unsigned int rx_active;
>> +
>> +	tx_active = t7xx_cldma_hw_queue_status(hw_info, CLDMA_ALL_Q, MTK_TX);
>> +	rx_active = t7xx_cldma_hw_queue_status(hw_info, CLDMA_ALL_Q, MTK_RX);
>> +	if (tx_active == CLDMA_INVALID_STATUS || rx_active == CLDMA_INVALID_STATUS)
> These cannot ever be true because of mask in t7xx_cldma_hw_queue_status().

t7xx_cldma_hw_queue_status() shouldn't apply the mask for CLDMA_ALL_Q.

>> +static int t7xx_cldma_clear_rxq(struct cldma_ctrl *md_ctrl, int qnum)
>> +{
>> +	struct cldma_queue *rxq = &md_ctrl->rxq[qnum];
>> +	struct cldma_request *req;
>> +	struct cldma_rgpd *rgpd;
>> +	unsigned long flags;
>> +
>> +	spin_lock_irqsave(&rxq->ring_lock, flags);
>> +	t7xx_cldma_q_reset(rxq);
>> +	list_for_each_entry(req, &rxq->tr_ring->gpd_ring, entry) {
>> +		rgpd = req->gpd;
>> +		rgpd->gpd_flags = GPD_FLAGS_IOC | GPD_FLAGS_HWO;
>> +		rgpd->data_buff_len = 0;
>> +
>> +		if (req->skb) {
>> +			req->skb->len = 0;
>> +			skb_reset_tail_pointer(req->skb);
>> +		}
>> +	}
>> +
>> +	spin_unlock_irqrestore(&rxq->ring_lock, flags);
>> +	list_for_each_entry(req, &rxq->tr_ring->gpd_ring, entry) {
>> +		int ret;
> I find this kind of newline+unlock+more code a bit odd groupingwise.
> IMO, the newline should be after the unlock rather than just before it to
> better indicate the critical sections visually.

Agree. In general, the driver uses a newline after '}', unlock 
operations should be an

exception since it looks better to keep the critical section blocks 
together.

...

>> +/**
>> + * t7xx_cldma_send_skb() - Send control data to modem.
>> + * @md_ctrl: CLDMA context structure.
>> + * @qno: Queue number.
>> + * @skb: Socket buffer.
>> + * @blocking: True for blocking operation.
>> + *
>> + * Send control packet to modem using a ring buffer.
>> + * If blocking is set, it will wait for completion.
>> + *
>> + * Return:
>> + * * 0		- Success.
>> + * * -ENOMEM	- Allocation failure.
>> + * * -EINVAL	- Invalid queue request.
>> + * * -EBUSY	- Resource lock failure.
>> + */
>> +int t7xx_cldma_send_skb(struct cldma_ctrl *md_ctrl, int qno, struct sk_buff *skb, bool blocking)
>> +{
>> +	struct cldma_request *tx_req;
>> +	struct cldma_queue *queue;
>> +	unsigned long flags;
>> +	int ret;
>> +
>> +	if (qno >= CLDMA_TXQ_NUM)
>> +		return -EINVAL;
>> +
>> +	queue = &md_ctrl->txq[qno];
>> +
>> +	spin_lock_irqsave(&md_ctrl->cldma_lock, flags);
>> +	if (!(md_ctrl->txq_active & BIT(qno))) {
>> +		ret = -EBUSY;
>> +		spin_unlock_irqrestore(&md_ctrl->cldma_lock, flags);
>> +		goto allow_sleep;
>> +	}
> ...
>> +		if (!blocking) {
>> +			ret = -EBUSY;
>> +			break;
>> +		}
>> +
>> +		ret = wait_event_interruptible_exclusive(queue->req_wq, queue->budget > 0);
>> +	} while (!ret);
>> +
>> +allow_sleep:
>> +	return ret;
>> +}
> First of all, if I interpreted the call chains correctly, this function is
> always called with blocking=true.
>
> Second, the first codepath returning -EBUSY when not txq_active seems
> twisted/reversed logic to me (not active => busy ?!?).

What about -EINVAL?

Other codes considered: -EPERM, -ENETDOWN.

>
...


  reply	other threads:[~2022-01-18 22:22 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 [this message]
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
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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