Re: [PATCH v4 09/15] dmaengine: ti: New driver for K3 UDMA - split#1: defines, structs, io func

Peter Ujfalusi
2019-11-11T08:32:13Z

On 11/11/2019 7.28, Vinod Koul wrote:
> On 01-11-19, 10:41, Peter Ujfalusi wrote:
>
>> +struct udma_chan {
>> + struct virt_dma_chan vc;
>> + struct dma_slave_config cfg;
>> + struct udma_dev *ud;
>> + struct udma_desc *desc;
>> + struct udma_desc *terminated_desc;
>
> descriptor and not a list?

Yes, not a list. I have only one transfer (if any) submitted to
hardware. This is mostly due to the packet mode RX operation: no
prelinked support in UDMAP so I need to have as many descriptors queued
up as the number of sg elements.

I need to keep the terminated descriptor around to be able to free it up
_after_ UDMAP returned it to avoid it modifying released memory.

>> + struct udma_static_tr static_tr;
>> + char *name;
>> +
>> + struct udma_tchan *tchan;
>> + struct udma_rchan *rchan;
>> + struct udma_rflow *rflow;
>> +
>> + bool psil_paired;
>> +
>> + int irq_num_ring;
>> + int irq_num_udma;
>> +
>> + bool cyclic;
>> + bool paused;
>> +
>> + enum udma_chan_state state;
>> + struct completion teardown_completed;
>> +
>> + u32 bcnt; /* number of bytes completed since the start of the channel */
>> + u32 in_ring_cnt; /* number of descriptors in flight */
>> +
>> + bool pkt_mode; /* TR or packet */
>> + bool needs_epib; /* EPIB is needed for the communication or not */
>> + u32 psd_size; /* size of Protocol Specific Data */
>> + u32 metadata_size; /* (needs_epib ? 16:0) + psd_size */
>> + u32 hdesc_size; /* Size of a packet descriptor in packet mode */
>> + bool notdpkt; /* Suppress sending TDC packet */
>> + int remote_thread_id;
>> + u32 src_thread;
>> + u32 dst_thread;
>> + enum psil_endpoint_type ep_type;
>> + bool enable_acc32;
>> + bool enable_burst;
>> + enum udma_tp_level channel_tpl; /* Channel Throughput Level */
>> +
>> + /* dmapool for packet mode descriptors */
>> + bool use_dma_pool;
>> + struct dma_pool *hdesc_pool;
>> +
>> + u32 id;
>> + enum dma_transfer_direction dir;
>
> why does channel have this, it already exists in descriptor

The channel can not change role, it is set when it was requested. In the
prep callbacks I do check if the direction matches with the channel's
direction.

>> +static irqreturn_t udma_udma_irq_handler(int irq, void *data)
>> +{
>> + struct udma_chan *uc = data;
>> +
>> + udma_tr_event_callback(uc);
>
> any reason why we want to call a fn and not code here..?

No particular reason, I'll move them.

- Péter