On 29/11/18 18:12, David Lechner wrote: > On 11/29/18 4:29 AM, Roger Quadros wrote: >> Bjorn, Suman, >> >> On 26/11/18 23:29, David Lechner wrote: >>> On 11/26/18 1:52 AM, Roger Quadros wrote: >>>> From: Suman Anna <s-anna@xxxxxx> >>>> >>>> The rproc_da_to_va() API is currently used to perform any device >>>> to kernel address translations to meet the different needs of the >>>> remoteproc core/platform drivers (eg: loading). The function also >>>> invokes the da_to_va ops, if present, to allow the remoteproc >>>> platform drivers to provide address translation. However, not all >>>> platform implementations have linear address spaces, and may need >>>> an additional parameter to be able to perform proper translations. >>>> >>>> The rproc_da_to_va() API and the rproc .da_to_va ops have therefore >>>> been expanded to take in an additional flags field enabling some >>>> remoteproc implementations (like the TI PRUSS remoteproc driver) >>>> to use these flags. Also, define some semantics for this flags >>>> argument as this can vary from one implementation to another. A >>>> new flags type is encoded into the upper 16 bits along side the >>>> actual value in the lower 16-bits for the flags argument, to >>>> allow different individual implementations to have better >>>> flexibility in interpreting the flags as per their needs. >>> >>> This seems like an overly complex solution for a rather simple >>> problem. Instead of passing all sorts of flags, could we just add >>> a parameter named "page" to da_to_va() that indicates the memory >>> page of the address in the remote processor? >>> >>> Or perhaps there is some other use for all of these flags that I >>> am not aware of? >> >> I'm not a big fan of this patch either. >> >> rproc_da_to_va() is used at the following places >> >> 2 qcom_q6v5_mss.c qcom_q6v5_dump_segment 974 void *ptr = rproc_da_to_va(rproc, segment->da, segment->size, >> 3 remoteproc_core.c rproc_da_to_va 197 void *rproc_da_to_va(struct rproc *rproc, u64 da, int len, u32 flags) >> 4 remoteproc_core.c rproc_handle_trace 582 ptr = rproc_da_to_va(rproc, rsc->da, rsc->len, RPROC_FLAGS_NONE); >> 5 remoteproc_core.c rproc_coredump 1592 ptr = rproc_da_to_va(rproc, segment->da, segment->size, >> 6 remoteproc_elf_loader.c rproc_elf_load_segments 185 ptr = rproc_da_to_va(rproc, da, memsz, >> 7 remoteproc_elf_loader.c rproc_elf_find_loaded_rsc_table 337 return rproc_da_to_va(rproc, shdr->sh_addr, shdr->sh_size, >> >> At rproc_elf_load_segments() we need to pass enough information so that >> the rproc driver can load the segment into proper area (IRAM vs DRAM). >> So providing page should suffice. > > FYI, the PRU series I sent a while back has some patches to do > something like this so feel free to use them if they are helpful. > > https://lore.kernel.org/lkml/20180623210810.21232-2-david@xxxxxxxxxxxxxx/ > https://lore.kernel.org/lkml/20180623210810.21232-3-david@xxxxxxxxxxxxxx/ > Thanks. I think we need to do something like that. Too bad you had to reverse engineer the TI specific headers. I'll check if we have this available somewhere internally. >> >> I want to understand more about rproc_elf_find_loaded_rsc_table() myself. >> rproc_elf_find_loaded_rsc_table() is called only in rproc_start() in remoteproc_core.c >> with the comment >> >> /* >> * The starting device has been given the rproc->cached_table as the >> * resource table. The address of the vring along with the other >> * allocated resources (carveouts etc) is stored in cached_table. >> * In order to pass this information to the remote device we must copy >> * this information to device memory. We also update the table_ptr so >> * that any subsequent changes will be applied to the loaded version. >> */ >> loaded_table = rproc_find_loaded_rsc_table(rproc, fw); >> >> Why isn't cached_table sufficient? >> Why do we need to call rproc_find_loaded_rsc_table()? >> >> why do we need to load the resource table into remote processor memory at all. >> As discussed earlier, some PRU systems have very little memory (512 bytes?) >> and we want to avoid unnecessary loading. >> This question still holds. Suman? cheers, -roger -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
