On Mon Nov 14, 2022 at 3:53 AM IST, Vinod Koul wrote: > On 11-11-22, 10:42, Sireesh Kodali wrote: > > On Fri Nov 4, 2022 at 6:10 PM IST, Vinod Koul wrote: > > > On 27-10-22, 10:44, Sireesh Kodali wrote: > > > > The IPA v2.x block, found on some older Qualcomm SoCs, uses BAM DMA to > > > > send and receive packets from the AP. It also uses BAM to receive > > > > commands from the AP (and possibly the modem). These commands are > > > > encoded as "Immediate Commands". They vary from regular BAM DMA > > > > commands. Adding support for immediate commands is trivial, but requires > > > > also adding Immediate Commands to the dmaengine API, which is what this > > > > patch series does. > > > > > > Can you explain a bit more. I understand you need "Immediate Commands" > > > but am really reluctant to add another interface to support a specific > > > use case > > > > > > > Apologies for the delayed response > > > > BAM supports both regular commands, and "immediate commands". Currently, > > commands are used by the Qualcom NAND chip driver, while "immediate > > commands" are intended to be used by the (yet to be mainlined) IPA > > driver. From the BAM driver perspective, both immediate and regular > > commands are simply a matter of setting the appropriate flag in the > > descriptor. I don't have access to the documentation on BAM to know > > exactly how these two modes differ, however I do know they are not > > interchangable. If a different API is suggested, I can change the > > implementation as needed. > > Ok, can you please explain what is meant by 'regular' cmd and > 'immediate', lets see what is required here I unfortunately don't have access to any documentation that explains the difference between the two. All I know is that IPA requires using immediate commands, while the QCOM NAND driver requires using 'regular' commands. Regards, Sireesh > > -- > ~Vinod
