From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> Sent: Wednesday, October 28, 2020 3:07 PM > On Wed, Oct 28, 2020 at 06:05:28AM +0000, Sherry Sun wrote: > > Hi Greg, > > > > > Subject: Re: [PATCH V5 0/2] Change vring space from nomal memory to > > > dma coherent memory > > > > > > On Wed, Oct 28, 2020 at 10:03:03AM +0800, Sherry Sun wrote: > > > > Changes in V5: > > > > 1. Reorganize the vop_mmap function code in patch 1, which is done > > > > by > > > Christoph. > > > > 2. Completely remove the unnecessary code related to reassign the > > > > used ring for card in patch 2. > > > > > > > > The original vop driver only supports dma coherent device, as it > > > > allocates and maps vring by _get_free_pages and dma_map_single, > > > > but not use dma_sync_single_for_cpu/device to sync the updates of > > > > device_page/vring between EP and RC, which will cause memory > > > > synchronization problem for device don't support hardware dma coherent. > > > > > > > > And allocate vrings use dma_alloc_coherent is a common way in > > > > kernel, as the memory interacted between two systems should use > > > > consistent memory to avoid caching effects. So here add > > > > noncoherent platform > > > support for vop driver. > > > > Also add some related dma changes to make sure noncoherent > > > > platform works well. > > > > > > > > Sherry Sun (2): > > > > misc: vop: change the way of allocating vrings and device page > > > > misc: vop: do not allocate and reassign the used ring > > > > > > > > drivers/misc/mic/bus/vop_bus.h | 2 + > > > > drivers/misc/mic/host/mic_boot.c | 9 ++ > > > > drivers/misc/mic/host/mic_main.c | 43 ++------ > > > > drivers/misc/mic/vop/vop_debugfs.c | 4 - > > > > drivers/misc/mic/vop/vop_main.c | 70 +----------- > > > > drivers/misc/mic/vop/vop_vringh.c | 166 ++++++++++------------------- > > > > include/uapi/linux/mic_common.h | 9 +- > > > > 7 files changed, 85 insertions(+), 218 deletions(-) > > > > > > Have you all seen: > > > > > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%25 > > > > 2Flore.kernel.org%2Fr%2F8c1443136563de34699d2c084df478181c205db4.16 > > > > 03854416.git.sudeep.dutt%40intel.com&data=04%7C01%7Csherry.sun% > > > > 40nxp.com%7Cc19c987667434969847e08d87b0685e8%7C686ea1d3bc2b4c6f > > > > a92cd99c5c301635%7C0%7C0%7C637394615238940323%7CUnknown%7CTW > > > > FpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJX > > > > VCI6Mn0%3D%7C1000&sdata=Zq%2FtHWTq%2BuIVBYXFGoeBmq0JJzYd > > > 9zDyv4NVN4TpC%2FU%3D&reserved=0 > > > > > > Looks like this code is asking to just be deleted, is that ok with you? > > > > Yes, I saw that patch. I'm ok with it. > > Great, can you please provide a "Reviewed-by:" or "Acked-by:" for it? > > thanks, > > greg k-h Sherry took much effort on the features support on i.MX series like i.MX8QM/i.MX8QXP/i.MX8MM. Now it is a pity to delete the vop code. One question, can we resubmit vop code by clean up, now only for i.MX series as Dutt's suggestion ? Or we have to drop the design and switch to select other solutions ? Thanks, Andy
