From: Sanjay R Mehta <sanmehta@amd.com>
To: Vinod Koul <vkoul@kernel.org>
Cc: Sanjay R Mehta <Sanju.Mehta@amd.com>,
gregkh@linuxfoundation.org, dan.j.williams@intel.com,
Thomas.Lendacky@amd.com, Shyam-sundar.S-k@amd.com,
Nehal-bakulchandra.Shah@amd.com, robh@kernel.org,
mchehab+samsung@kernel.org, davem@davemloft.net,
linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org
Subject: Re: [PATCH v9 2/3] dmaengine: ptdma: register PTDMA controller as a DMA resource
Date: Wed, 16 Jun 2021 10:53:35 +0530 [thread overview]
Message-ID: <22205182-198c-da65-b907-357280dff463@amd.com> (raw)
In-Reply-To: <YMl7f/nNRMUgFDyq@vkoul-mobl>
On 6/16/2021 9:48 AM, Vinod Koul wrote:
> [CAUTION: External Email]
>
> On 15-06-21, 17:04, Sanjay R Mehta wrote:
>>
>>
>> On 6/9/2021 12:26 AM, Vinod Koul wrote:
>>
>> [snipped]
>>
>>>> +static struct pt_dma_desc *pt_alloc_dma_desc(struct pt_dma_chan *chan,
>>>> + unsigned long flags)
>>>> +{
>>>> + struct pt_dma_desc *desc;
>>>> +
>>>> + desc = kmem_cache_zalloc(chan->pt->dma_desc_cache, GFP_NOWAIT);
>>>> + if (!desc)
>>>> + return NULL;
>>>> +
>>>> + vchan_tx_prep(&chan->vc, &desc->vd, flags);
>>>> +
>>>> + desc->pt = chan->pt;
>>>> + desc->issued_to_hw = 0;
>>>> + INIT_LIST_HEAD(&desc->cmdlist);
>>>
>>> why do you need your own list, the lists in vc should suffice?
>>>
>>
>> Do you think this should be a major blocker for pulling this series in 5.14?
>> Would you be okay to accept this change in the subsequent driver updates?
>
> Sorry that is not how upstream works, I would like things to be better
> before we merge this
>
Sure Vinod, I will fix this and send the change in next version.
>>
>>>> +static int pt_resume(struct dma_chan *dma_chan)
>>>> +{
>>>> + struct pt_dma_chan *chan = to_pt_chan(dma_chan);
>>>> + struct pt_dma_desc *desc = NULL;
>>>> + unsigned long flags;
>>>> +
>>>> + spin_lock_irqsave(&chan->vc.lock, flags);
>>>> + pt_start_queue(&chan->pt->cmd_q);
>>>> + desc = __pt_next_dma_desc(chan);
>>>> + spin_unlock_irqrestore(&chan->vc.lock, flags);
>>>> +
>>>> + /* If there was something active, re-start */
>>>> + if (desc)
>>>> + pt_cmd_callback(desc, 0);
>>>
>>> this doesn't sound correct. In pause yoy stop the queue, so start of the
>>> queue should be done here... Why grab a descriptor?
>>>
>>>> +static int pt_terminate_all(struct dma_chan *dma_chan)
>>>> +{
>>>> + struct pt_dma_chan *chan = to_pt_chan(dma_chan);
>>>> +
>>>> + vchan_free_chan_resources(&chan->vc);
>>>
>>> what about the descriptors, are you not going to clear the lists and
>>> free them..
>>>
>>>> +int pt_dmaengine_register(struct pt_device *pt)
>>>> +{
>>>> + struct pt_dma_chan *chan;
>>>> + struct dma_device *dma_dev = &pt->dma_dev;
>>>> + char *cmd_cache_name;
>>>> + char *desc_cache_name;
>>>> + int ret;
>>>> +
>>>> + pt->pt_dma_chan = devm_kzalloc(pt->dev, sizeof(*pt->pt_dma_chan),
>>>> + GFP_KERNEL);
>>>> + if (!pt->pt_dma_chan)
>>>> + return -ENOMEM;
>>>> +
>>>> + cmd_cache_name = devm_kasprintf(pt->dev, GFP_KERNEL,
>>>> + "%s-dmaengine-cmd-cache",
>>>> + pt->name);
>>>> + if (!cmd_cache_name)
>>>> + return -ENOMEM;
>>>> +
>>>> + pt->dma_cmd_cache = kmem_cache_create(cmd_cache_name,
>>>> + sizeof(struct pt_dma_cmd),
>>>> + sizeof(void *),
>>>> + SLAB_HWCACHE_ALIGN, NULL);
>>>> + if (!pt->dma_cmd_cache)
>>>> + return -ENOMEM;
>>>> +
>>>> + desc_cache_name = devm_kasprintf(pt->dev, GFP_KERNEL,
>>>> + "%s-dmaengine-desc-cache",
>>>> + pt->name);
>>>> + if (!desc_cache_name) {
>>>> + ret = -ENOMEM;
>>>> + goto err_cache;
>>>> + }
>>>> +
>>>> + pt->dma_desc_cache = kmem_cache_create(desc_cache_name,
>>>> + sizeof(struct pt_dma_desc),
>>>> + sizeof(void *),
>>>
>>> sizeof void ptr?
>
> This and many more comments are left not replied, do you agree to them,
> do you disagree, hard to tell from silence..
>
Yes, I agree with all other comments and will send the changes in next
version of the patch series.
>>>
>>>> + SLAB_HWCACHE_ALIGN, NULL);
>>>> + if (!pt->dma_desc_cache) {
>>>> + ret = -ENOMEM;
>>>> + goto err_cache;
>>>> + }
>>>> +
>>>> + dma_dev->dev = pt->dev;
>>>> + dma_dev->src_addr_widths = DMA_SLAVE_BUSWIDTH_64_BYTES;
>>>> + dma_dev->dst_addr_widths = DMA_SLAVE_BUSWIDTH_64_BYTES;
>>>> + dma_dev->directions = DMA_MEM_TO_MEM;
>>>> + dma_dev->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
>>>> + dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask);
>>>> + dma_cap_set(DMA_INTERRUPT, dma_dev->cap_mask);
>>>> + dma_cap_set(DMA_PRIVATE, dma_dev->cap_mask);
>>>
>>> Why DMA_PRIVATE ? this is a dma mempcy controller ...
>>
>> This DMA controller is intended to be used with AMD Non-Transparent
>> Bridge devices and not for general purpose peripheral DMA. Hence marking
>> it as DMA_PRIVATE.
>
> Okay, maybe add a comment so that people would know
>
Sure. I will add comment here.
> --
> ~Vinod
>
next prev parent reply other threads:[~2021-06-16 5:23 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-02 17:22 [PATCH v9 0/3] Add support for AMD PTDMA controller driver Sanjay R Mehta
2021-06-02 17:22 ` [PATCH v9 1/3] dmaengine: ptdma: Initial driver for the AMD PTDMA Sanjay R Mehta
2021-06-08 17:39 ` Vinod Koul
2021-06-15 11:20 ` Sanjay R Mehta
2021-06-16 4:15 ` Vinod Koul
2021-06-16 4:54 ` Sanjay R Mehta
2021-06-16 6:16 ` Greg KH
2021-06-16 6:57 ` Sanjay R Mehta
2021-06-16 7:17 ` Greg KH
2021-06-16 7:52 ` Vinod Koul
2021-06-16 7:59 ` Greg KH
2021-06-16 9:46 ` Sanjay R Mehta
2021-06-16 9:56 ` Vinod Koul
2021-06-16 12:00 ` Sanjay R Mehta
2021-06-16 12:23 ` Greg KH
2021-06-16 12:53 ` Sanjay R Mehta
2021-06-16 12:57 ` Greg KH
2021-06-02 17:22 ` [PATCH v9 2/3] dmaengine: ptdma: register PTDMA controller as a DMA resource Sanjay R Mehta
2021-06-08 18:56 ` Vinod Koul
2021-06-15 11:34 ` Sanjay R Mehta
2021-06-16 4:18 ` Vinod Koul
2021-06-16 5:23 ` Sanjay R Mehta [this message]
2021-06-20 3:52 ` Sanjay R Mehta
2021-06-02 17:22 ` [PATCH v9 3/3] dmaengine: ptdma: Add debugfs entries for PTDMA Sanjay R Mehta
2021-06-09 14:10 ` Vinod Koul
2021-06-15 11:18 ` Sanjay R Mehta
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