From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Cc: 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,
dinesh.sharma@intel.com, eliot.lee@intel.com,
ilpo.johannes.jarvinen@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: Fri, 14 Jan 2022 16:13:29 +0200 [thread overview]
Message-ID: <YeGFCYTaQ0GNLhyx@smile.fi.intel.com> (raw)
In-Reply-To: <20220114010627.21104-3-ricardo.martinez@linux.intel.com>
On Thu, Jan 13, 2022 at 06:06:16PM -0700, Ricardo Martinez wrote:
> From: Haijun Liu <haijun.liu@mediatek.com>
>
> Cross Layer DMA (CLDMA) Hardware interface (HIF) enables the control
> path of Host-Modem data transfers. CLDMA HIF layer provides a common
> interface to the Port Layer.
>
> CLDMA manages 8 independent RX/TX physical channels with data flow
> control in HW queues. CLDMA uses ring buffers of General Packet
> Descriptors (GPD) for TX/RX. GPDs can represent multiple or single
> data buffers (DB).
>
> CLDMA HIF initializes GPD rings, registers ISR handlers for CLDMA
> interrupts, and initializes CLDMA HW registers.
>
> CLDMA TX flow:
> 1. Port Layer write
> 2. Get DB address
> 3. Configure GPD
> 4. Triggering processing via HW register write
>
> CLDMA RX flow:
> 1. CLDMA HW sends a RX "done" to host
> 2. Driver starts thread to safely read GPD
> 3. DB is sent to Port layer
> 4. Create a new buffer for GPD ring
...
> + * Copyright (c) 2021, Intel Corporation.
2021-2022 (in all files)?
...
> +#include <linux/dev_printk.h>
> +#include <linux/device.h>
I believe the former is guaranteed to be included in the latter.
The rest of the headers in this file looks good to me.
...
> + if (dma_mapping_error(md_ctrl->dev, req->mapped_buff)) {
> + dev_err(md_ctrl->dev, "DMA mapping failed\n");
Can we first free resources and then print messages?
Printing messages is a slow path and freeing resources first is a good
(micro-)optimization.
> + dev_kfree_skb_any(req->skb);
> + req->skb = NULL;
> + req->mapped_buff = 0;
> + return -ENOMEM;
> + }
...
> +static int t7xx_cldma_rx_ring_init(struct cldma_ctrl *md_ctrl, struct cldma_ring *ring)
> +{
> + struct cldma_request *req, *first_req = NULL;
> + struct cldma_rgpd *prev_gpd, *gpd = NULL;
> + int i;
> +
> + for (i = 0; i < ring->length; i++) {
> + req = t7xx_alloc_rx_request(md_ctrl, ring->pkt_size);
> + if (!req) {
> + t7xx_cldma_ring_free(md_ctrl, ring, DMA_FROM_DEVICE);
> + return -ENOMEM;
> + }
> +
> + gpd = req->gpd;
> + t7xx_cldma_rgpd_set_data_ptr(gpd, req->mapped_buff);
> + gpd->data_allow_len = cpu_to_le16(ring->pkt_size);
> + gpd->gpd_flags = GPD_FLAGS_IOC | GPD_FLAGS_HWO;
> +
> + if (i)
> + t7xx_cldma_rgpd_set_next_ptr(prev_gpd, req->gpd_addr);
> + else
> + first_req = req;
> +
> + INIT_LIST_HEAD(&req->entry);
> + list_add_tail(&req->entry, &ring->gpd_ring);
> + prev_gpd = gpd;
> + }
> + if (first_req)
At which circumstances it is not defined? Only when ring->length == 0, right?
> + t7xx_cldma_rgpd_set_next_ptr(gpd, first_req->gpd_addr);
Looking into this, perhaps it makes sense to refactor this way:
1. Define list head pointer on the stack
2. Iterate over the ring->length and add elements to that list
3. Iterate over the list and set the DMA links
(t7xx_cldma_rgpd_set_next_ptr() calls)
4. Add this list to the main one.
> + return 0;
> +}
...
> +static int t7xx_cldma_tx_ring_init(struct cldma_ctrl *md_ctrl, struct cldma_ring *ring)
> +{
> + struct cldma_request *req, *first_req = NULL;
> + struct cldma_tgpd *tgpd, *prev_gpd;
> + int i;
> +
> + for (i = 0; i < ring->length; i++) {
> + req = t7xx_alloc_tx_request(md_ctrl);
> + if (!req) {
> + t7xx_cldma_ring_free(md_ctrl, ring, DMA_TO_DEVICE);
> + return -ENOMEM;
> + }
> +
> + tgpd = req->gpd;
> + tgpd->gpd_flags = GPD_FLAGS_IOC;
> +
> + if (!first_req)
> + first_req = req;
> + else
> + t7xx_cldma_tgpd_set_next_ptr(prev_gpd, req->gpd_addr);
> +
> + INIT_LIST_HEAD(&req->entry);
> + list_add_tail(&req->entry, &ring->gpd_ring);
> + prev_gpd = tgpd;
> + }
> +
> + if (first_req)
> + t7xx_cldma_tgpd_set_next_ptr(tgpd, first_req->gpd_addr);
> +
> + return 0;
Ditto.
> +}
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2022-01-14 14:15 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 [this message]
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
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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