Re: [PATCH v3 11/15] dmaengine: sh: rz-dmac: Add cyclic DMA support

[Claudiu Beznea <claudiu.beznea@tuxon.dev>]

Hi, Biju,

On 4/7/26 17:36, Biju Das wrote:
> 
> Hi Claudiu,
> 
> Thanks for the patch.
> 
>> -----Original Message-----
>> From: Claudiu <claudiu.beznea@tuxon.dev>
>> Sent: 07 April 2026 14:35
>> Subject: [PATCH v3 11/15] dmaengine: sh: rz-dmac: Add cyclic DMA support
>>
>> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>
>> Add cyclic DMA support to the RZ DMAC driver. A per-channel status bit is introduced to mark cyclic
>> channels and is set during the DMA prepare callback. The IRQ handler checks this status bit and calls
>> vchan_cyclic_callback() accordingly.
>>
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>> ---
>>
>> Changes in v3:
>> - updated rz_dmac_lmdesc_recycle() to restore the lmdesc->nxla
>> - in rz_dmac_prepare_descs_for_cyclic() update directly the
>>    desc->start_lmdesc with the descriptor pointer insted of the
>>    descriptor address
>> - used rz_dmac_lmdesc_addr() to compute the descritor address
>> - set channel->status = 0 in rz_dmac_free_chan_resources()
>> - in rz_dmac_prep_dma_cyclic() check for invalid periods or buffer len
>>    and limit the critical area protected by spinlock
>> - set channel->status = 0 in rz_dmac_terminate_all()
>> - updated rz_dmac_calculate_residue_bytes_in_vd() to use
>>    rz_dmac_lmdesc_addr()
>> - dropped goto in rz_dmac_irq_handler_thread() as it is not needed
>>    anymore; dropped also the local variable desc
>>
>> Changes in v2:
>> - none
>>
>>   drivers/dma/sh/rz-dmac.c | 144 +++++++++++++++++++++++++++++++++++++--
>>   1 file changed, 138 insertions(+), 6 deletions(-)
>>

[ ... ]

>> @@ -500,6 +562,8 @@ static void rz_dmac_free_chan_resources(struct dma_chan *chan)
>>   		channel->mid_rid = -EINVAL;
>>   	}
>>
>> +	channel->status = 0;
>> +
>>   	spin_unlock_irqrestore(&channel->vc.lock, flags);
> 
> Maybe create a patch to convert all the spin_{lock,unlock} with guard()
> in this driver.

This series already has to many patches and I want to keep only what is 
necessary for the cyclic support. My plan is to do the guard conversion after 
cyclic support gets merged.

Thank you,
Claudiu