[PATCH V4 0/2] Change vring space from nomal memory to dma coherent memory

From: Sherry Sun
Date: Mon Oct 26 2020 - 04:55:24 EST


Changes in V4:
1. Change to use dma_mmap_coherent api for vop mmap callback.
2. Add dp_mmap callback to map device page to userspace instead of get_dp_dma
callback.
3. Move all the dma related changes to patch 1.
4. Kill the mic_dp_init/mic_dp_uninit and inline those into the callers as
Christoph suggested.
5. Keep the code following the 80-character line rule.
6. Add endian swap for vqconfig[i].address.

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 vring 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 | 2 -
drivers/misc/mic/vop/vop_main.c | 51 +++----------
drivers/misc/mic/vop/vop_vringh.c | 110 +++++++++--------------------
include/uapi/linux/mic_common.h | 5 +-
7 files changed, 66 insertions(+), 156 deletions(-)

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2.17.1