Re: [PATCH 16/19] drm/msm/a6xx: Add support for per-instance pagetables

Rob Clark
2020-08-17T18:55:23Z

On Mon, Aug 17, 2020 at 8:41 AM Akhil P Oommen <akhilpo@codeaurora.org> wrote:
>
> On 8/14/2020 8:11 AM, Rob Clark wrote:
> > From: Jordan Crouse <jcrouse@codeaurora.org>
> >
> > Add support for using per-instance pagetables if all the dependencies are
> > available.
> >
> > Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
> > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > ---
> > drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 70 +++++++++++++++++++++++++++
> > drivers/gpu/drm/msm/adreno/a6xx_gpu.h | 1 +
> > drivers/gpu/drm/msm/msm_ringbuffer.h | 1 +
> > 3 files changed, 72 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > index 5eabb0109577..9653ac9b3cb8 100644
> > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > @@ -81,6 +81,56 @@ static void get_stats_counter(struct msm_ringbuffer *ring, u32 counter,
> > OUT_RING(ring, upper_32_bits(iova));
> > }
> >
> > +static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu,
> > + struct msm_ringbuffer *ring, struct msm_file_private *ctx)
> > +{
> > + phys_addr_t ttbr;
> > + u32 asid;
> > + u64 memptr = rbmemptr(ring, ttbr0);
> > +
> > + if (ctx == a6xx_gpu->cur_ctx)
> > + return;
> > +
> > + if (msm_iommu_pagetable_params(ctx->aspace->mmu, &ttbr, &asid))
> > + return;
> > +
> > + /* Execute the table update */
> > + OUT_PKT7(ring, CP_SMMU_TABLE_UPDATE, 4);
> > + OUT_RING(ring, CP_SMMU_TABLE_UPDATE_0_TTBR0_LO(lower_32_bits(ttbr)));
> > +
> > + /*
> > + * For now ignore the asid since the smmu driver uses a TLBIASID to
> > + * flush the TLB when we use iommu_flush_tlb_all() and the smmu driver
> > + * isn't aware that the asid changed. Instead, keep the default asid
> > + * (0, same as the context bank) to make sure the TLB is properly
> > + * flushed.
> > + */
> > + OUT_RING(ring,
> > + CP_SMMU_TABLE_UPDATE_1_TTBR0_HI(upper_32_bits(ttbr)) |
> > + CP_SMMU_TABLE_UPDATE_1_ASID(0));
> > + OUT_RING(ring, CP_SMMU_TABLE_UPDATE_2_CONTEXTIDR(0));
> > + OUT_RING(ring, CP_SMMU_TABLE_UPDATE_3_CONTEXTBANK(0));
> > +
> > + /*
> > + * Write the new TTBR0 to the memstore. This is good for debugging.
> > + */
> > + OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > + OUT_RING(ring, CP_MEM_WRITE_0_ADDR_LO(lower_32_bits(memptr)));
> > + OUT_RING(ring, CP_MEM_WRITE_1_ADDR_HI(upper_32_bits(memptr)));
> > + OUT_RING(ring, lower_32_bits(ttbr));
> > + OUT_RING(ring, (0 << 16) | upper_32_bits(ttbr));
> why (0 << 16) is required here?

That would normally be (asid << 16), except due to the way we
currently flush tlb, we need to use asid==0..

(Although msm_iommu_pagetable_params() should return asid==0, I fixed
that in msm_iommu_pagetable_create() and didn't notice that Jordan had
fixed that here instead)

BR,
-R

> > +
> > + /*
> > + * And finally, trigger a uche flush to be sure there isn't anything
> > + * lingering in that part of the GPU
> > + */
> > +
> > + OUT_PKT7(ring, CP_EVENT_WRITE, 1);
> > + OUT_RING(ring, 0x31);
> This may be unnecessary, but no harm in keeping it. SMMU_TABLE_UPDATE is
> supposed to do a UCHE flush.
>
> -Akhil
> > +
> > + a6xx_gpu->cur_ctx = ctx;
> > +}
> > +
> > static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > {
> > unsigned int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;
> > @@ -90,6 +140,8 @@ static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > struct msm_ringbuffer *ring = submit->ring;
> > unsigned int i;
> >
> > + a6xx_set_pagetable(a6xx_gpu, ring, submit->queue->ctx);
> > +
> > get_stats_counter(ring, REG_A6XX_RBBM_PERFCTR_CP_0_LO,
> > rbmemptr_stats(ring, index, cpcycles_start));
> >
> > @@ -696,6 +748,8 @@ static int a6xx_hw_init(struct msm_gpu *gpu)
> > /* Always come up on rb 0 */
> > a6xx_gpu->cur_ring = gpu->rb[0];
> >
> > + a6xx_gpu->cur_ctx = NULL;
> > +
> > /* Enable the SQE_to start the CP engine */
> > gpu_write(gpu, REG_A6XX_CP_SQE_CNTL, 1);
> >
> > @@ -1008,6 +1062,21 @@ static unsigned long a6xx_gpu_busy(struct msm_gpu *gpu)
> > return (unsigned long)busy_time;
> > }
> >
> > +static struct msm_gem_address_space *
> > +a6xx_create_private_address_space(struct msm_gpu *gpu)
> > +{
> > + struct msm_gem_address_space *aspace = NULL;
> > + struct msm_mmu *mmu;
> > +
> > + mmu = msm_iommu_pagetable_create(gpu->aspace->mmu);
> > +
> > + if (!IS_ERR(mmu))
> > + aspace = msm_gem_address_space_create(mmu,
> > + "gpu", 0x100000000ULL, 0x1ffffffffULL);
> > +
> > + return aspace;
> > +}
> > +
> > static const struct adreno_gpu_funcs funcs = {
> > .base = {
> > .get_param = adreno_get_param,
> > @@ -1031,6 +1100,7 @@ static const struct adreno_gpu_funcs funcs = {
> > .gpu_state_put = a6xx_gpu_state_put,
> > #endif
> > .create_address_space = adreno_iommu_create_address_space,
> > + .create_private_address_space = a6xx_create_private_address_space,
> > },
> > .get_timestamp = a6xx_get_timestamp,
> > };
> > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > index 03ba60d5b07f..da22d7549d9b 100644
> > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > @@ -19,6 +19,7 @@ struct a6xx_gpu {
> > uint64_t sqe_iova;
> >
> > struct msm_ringbuffer *cur_ring;
> > + struct msm_file_private *cur_ctx;
> >
> > struct a6xx_gmu gmu;
> > };
> > diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.h b/drivers/gpu/drm/msm/msm_ringbuffer.h
> > index 7764373d0ed2..0987d6bf848c 100644
> > --- a/drivers/gpu/drm/msm/msm_ringbuffer.h
> > +++ b/drivers/gpu/drm/msm/msm_ringbuffer.h
> > @@ -31,6 +31,7 @@ struct msm_rbmemptrs {
> > volatile uint32_t fence;
> >
> > volatile struct msm_gpu_submit_stats stats[MSM_GPU_SUBMIT_STATS_COUNT];
> > + volatile u64 ttbr0;
> > };
> >
> > struct msm_ringbuffer {
> >
>