From: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
To: "Martinez, Ricardo" <ricardo.martinez@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: Wed, 19 Jan 2022 11:52:40 +0200 (EET) [thread overview]
Message-ID: <cb33ee41-b885-6523-199-b8a339c1a531@linux.intel.com> (raw)
In-Reply-To: <4a4b2848-d665-c9ba-c66a-dd4408e94ea5@linux.intel.com>
[-- Attachment #1: Type: text/plain, Size: 3585 bytes --]
On Tue, 18 Jan 2022, Martinez, Ricardo wrote:
>
> 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.
Please note this in your commit message then and I think it should be
fine to leave it as is (or use 1 sized array, if you prefer to).
> 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 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.
I guess it shouldn't but it currently does apply 0xff (CLDMA_ALL_Q) as
mask in that case. However, this now raises another question, if
0xffffffff (CLDMA_INVALID_STATUS) means status is invalid, should all
callers both single Q and CLDMA_ALL_Q be returned/check/handle that value?
Why would CLDMA_ALL_Q be special in this respect that the INVALID_STATUS
means invalid only with it?
> > > +/**
> > > + * 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.
How about -EIO.
--
i.
next prev parent reply other threads:[~2022-01-19 9:53 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 [this message]
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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