gpu: nvgpu: Use coherent aperture flag

When using a coherent DMA API wee must make sure to program
any aperture fields with the coherent aperture setting. To
do this the nvgpu_aperture_mask() function was modified to
take a third aperture mask argument, a coherent setting, so
that code can use this function to generate coherent aperture
settings.

The aperture choice is some what tricky: the default version
of this function uses the state of the DMA API to determine
what aperture to use for SYSMEM: either coherent or
non-coherent internally. Thus a kernel user need only specify
the normal nvgpu_mem struct and the correct mask should be
chosen. Due to many uses of nvgpu_mem structs not created
directly from the DMA API wrapper it's easier to translate
SYSMEM to SYSMEM_COH after creation.

However, the GMMU mapping code, will encounter buffers from
userspace with difference coerency attributes than the DMA
API. Thus the __nvgpu_aperture_mask() really respects the
aperture setting passed in regardless of the DMA API state.
This aperture setting is pulled from NVGPU_VM_MAP_IO_COHERENT
since this is either passed in from userspace or set by the
kernel when using coherent DMA. The aperture field in attrs
is upgraded to coh if this flag is set.

This change also adds a coherent sysmem mask everywhere that
it can. There's a couple places that do not have a coherent
register field defined yet. These need to eventually be
defined and added.

Lastly the aperture mask code has been mvoed from the Linux
vm.c code to the general vm.c code since this function has
no Linux dependencies.

Note: depends on https://git-master.nvidia.com/r/1664536 for
new register fields.

JIRA EVLR-2333

Change-Id: I4b347911ecb7c511738563fe6c34d0e6aa380d71
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1655220
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

2 files changed, 54 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/common/mm/gmmu.c b/drivers/gpu/nvgpu/common/mm/gmmu.c
index 5abf5951..41343718 100644
--- a/drivers/gpu/nvgpu/common/mm/gmmu.c
+++ b/drivers/gpu/nvgpu/common/mm/gmmu.c
@@ -634,7 +634,7 @@ static int __nvgpu_gmmu_update_page_table(struct vm_gk20a *vm,
                    page_size >> 10,
                    nvgpu_gmmu_perm_str(attrs->rw_flag),
                    attrs->kind_v,
-                   nvgpu_aperture_str(attrs->aperture),
+                   nvgpu_aperture_str(g, attrs->aperture),
                    attrs->cacheable ? 'C' : '-',
                    attrs->sparse    ? 'S' : '-',
                    attrs->priv      ? 'P' : '-',
@@ -712,6 +712,13 @@ u64 gk20a_locked_gmmu_map(struct vm_gk20a *vm,
         attrs.l3_alloc = (bool)(flags & NVGPU_VM_MAP_L3_ALLOC);
 
         /*
+         * Handle the IO coherency aperture: make sure the .aperture field is
+         * correct based on the IO coherency flag.
+         */
+        if (attrs.coherent && attrs.aperture == APERTURE_SYSMEM)
+                attrs.aperture = __APERTURE_SYSMEM_COH;
+
+        /*
          * Only allocate a new GPU VA range if we haven't already been passed a
          * GPU VA range. This facilitates fixed mappings.
          */
diff --git a/drivers/gpu/nvgpu/common/mm/nvgpu_mem.c b/drivers/gpu/nvgpu/common/mm/nvgpu_mem.c
index 73b6b2a7..78a57b4e 100644
--- a/drivers/gpu/nvgpu/common/mm/nvgpu_mem.c
+++ b/drivers/gpu/nvgpu/common/mm/nvgpu_mem.c
@@ -28,6 +28,52 @@
 
 #include "gk20a/gk20a.h"
 
+/*
+ * Make sure to use the right coherency aperture if you use this function! This
+ * will not add any checks. If you want to simply use the default coherency then
+ * use nvgpu_aperture_mask().
+ */
+u32 __nvgpu_aperture_mask(struct gk20a *g, enum nvgpu_aperture aperture,
+                          u32 sysmem_mask, u32 sysmem_coh_mask, u32 vidmem_mask)
+{
+        /*
+         * Some iGPUs treat sysmem (i.e SoC DRAM) as vidmem. In these cases the
+         * "sysmem" aperture should really be translated to VIDMEM.
+         */
+        if (!nvgpu_is_enabled(g, NVGPU_MM_HONORS_APERTURE))
+                aperture = APERTURE_VIDMEM;
+
+        switch (aperture) {
+        case __APERTURE_SYSMEM_COH:
+                return sysmem_coh_mask;
+        case APERTURE_SYSMEM:
+                return sysmem_mask;
+        case APERTURE_VIDMEM:
+                return vidmem_mask;
+        case APERTURE_INVALID:
+                WARN_ON("Bad aperture");
+        }
+        return 0;
+}
+
+u32 nvgpu_aperture_mask(struct gk20a *g, struct nvgpu_mem *mem,
+                        u32 sysmem_mask, u32 sysmem_coh_mask, u32 vidmem_mask)
+{
+        enum nvgpu_aperture ap = mem->aperture;
+
+        /*
+         * Handle the coherent aperture: ideally most of the driver is not
+         * aware of the difference between coherent and non-coherent sysmem so
+         * we add this translation step here.
+         */
+        if (nvgpu_is_enabled(g, NVGPU_USE_COHERENT_SYSMEM) &&
+            ap == APERTURE_SYSMEM)
+                ap = __APERTURE_SYSMEM_COH;
+
+        return __nvgpu_aperture_mask(g, ap,
+                                     sysmem_mask, sysmem_coh_mask, vidmem_mask);
+}
+
 void *nvgpu_sgt_get_next(struct nvgpu_sgt *sgt, void *sgl)
 {
         return sgt->ops->sgl_next(sgl);