Re: [PATCH 2/9] Revert "drm/msm/a6xx: Use the DMA API for GMU memory objects"

From: Rob Clark
Date: Mon Apr 20 2020 - 17:16:20 EST

On Mon, Apr 20, 2020 at 12:59 PM Jonathan Marek <jonathan@xxxxxxxx> wrote:
>
> On 4/20/20 3:51 PM, Bjorn Andersson wrote:
> > On Mon 20 Apr 07:03 PDT 2020, Jonathan Marek wrote:
> >
> >> This reverts commit a5fb8b918920c6f7706a8b5b8ea535a7f077a7f6.
> >
> > Why?
> >
>
> It removes something I need for the next patches in the series, however
> I'm open to suggestions on a better solution (Jordan said he would check
> it out)

when you repost (if we end up keeping this approach), please add a
description of the reason in the commit msg of the revert.. it makes
it easier to review and less confusing in git history

BR,
-R


> >> ---
> >> drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 115 +++++++++++++++++++++++---
> >> drivers/gpu/drm/msm/adreno/a6xx_gmu.h | 6 +-
> >> 2 files changed, 107 insertions(+), 14 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
> >> index c4e71abbdd53..748cd379065f 100644
> >> --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
> >> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
> >> @@ -2,7 +2,6 @@
> >> /* Copyright (c) 2017-2019 The Linux Foundation. All rights reserved. */
> >>
> >> #include <linux/clk.h>
> >> -#include <linux/dma-mapping.h>
> >> #include <linux/interconnect.h>
> >> #include <linux/pm_domain.h>
> >> #include <linux/pm_opp.h>
> >> @@ -921,10 +920,21 @@ int a6xx_gmu_stop(struct a6xx_gpu *a6xx_gpu)
> >>
> >> static void a6xx_gmu_memory_free(struct a6xx_gmu *gmu, struct a6xx_gmu_bo *bo)
> >> {
> >> + int count, i;
> >> + u64 iova;
> >> +
> >> if (IS_ERR_OR_NULL(bo))
> >> return;
> >>
> >> - dma_free_wc(gmu->dev, bo->size, bo->virt, bo->iova);
> >> + count = bo->size >> PAGE_SHIFT;
> >> + iova = bo->iova;
> >> +
> >> + for (i = 0; i < count; i++, iova += PAGE_SIZE) {
> >> + iommu_unmap(gmu->domain, iova, PAGE_SIZE);
> >> + __free_pages(bo->pages[i], 0);
> >> + }
> >> +
> >> + kfree(bo->pages);
> >> kfree(bo);
> >> }
> >>
> >> @@ -932,6 +942,7 @@ static struct a6xx_gmu_bo *a6xx_gmu_memory_alloc(struct a6xx_gmu *gmu,
> >> size_t size)
> >> {
> >> struct a6xx_gmu_bo *bo;
> >> + int ret, count, i;
> >>
> >> bo = kzalloc(sizeof(*bo), GFP_KERNEL);
> >> if (!bo)
> >> @@ -939,14 +950,86 @@ static struct a6xx_gmu_bo *a6xx_gmu_memory_alloc(struct a6xx_gmu *gmu,
> >>
> >> bo->size = PAGE_ALIGN(size);
> >>
> >> - bo->virt = dma_alloc_wc(gmu->dev, bo->size, &bo->iova, GFP_KERNEL);
> >> + count = bo->size >> PAGE_SHIFT;
> >>
> >> - if (!bo->virt) {
> >> + bo->pages = kcalloc(count, sizeof(struct page *), GFP_KERNEL);
> >> + if (!bo->pages) {
> >> kfree(bo);
> >> return ERR_PTR(-ENOMEM);
> >> }
> >>
> >> + for (i = 0; i < count; i++) {
> >> + bo->pages[i] = alloc_page(GFP_KERNEL);
> >> + if (!bo->pages[i])
> >> + goto err;
> >> + }
> >> +
> >> + bo->iova = gmu->uncached_iova_base;
> >> +
> >> + for (i = 0; i < count; i++) {
> >> + ret = iommu_map(gmu->domain,
> >> + bo->iova + (PAGE_SIZE * i),
> >> + page_to_phys(bo->pages[i]), PAGE_SIZE,
> >> + IOMMU_READ | IOMMU_WRITE);
> >> +
> >> + if (ret) {
> >> + DRM_DEV_ERROR(gmu->dev, "Unable to map GMU buffer object\n");
> >> +
> >> + for (i = i - 1 ; i >= 0; i--)
> >> + iommu_unmap(gmu->domain,
> >> + bo->iova + (PAGE_SIZE * i),
> >> + PAGE_SIZE);
> >> +
> >> + goto err;
> >> + }
> >> + }
> >> +
> >> + bo->virt = vmap(bo->pages, count, VM_IOREMAP,
> >> + pgprot_writecombine(PAGE_KERNEL));
> >> + if (!bo->virt)
> >> + goto err;
> >> +
> >> + /* Align future IOVA addresses on 1MB boundaries */
> >> + gmu->uncached_iova_base += ALIGN(size, SZ_1M);
> >> +
> >> return bo;
> >> +
> >> +err:
> >> + for (i = 0; i < count; i++) {
> >> + if (bo->pages[i])
> >> + __free_pages(bo->pages[i], 0);
> >> + }
> >> +
> >> + kfree(bo->pages);
> >> + kfree(bo);
> >> +
> >> + return ERR_PTR(-ENOMEM);
> >> +}
> >> +
> >> +static int a6xx_gmu_memory_probe(struct a6xx_gmu *gmu)
> >> +{
> >> + int ret;
> >> +
> >> + /*
> >> + * The GMU address space is hardcoded to treat the range
> >> + * 0x60000000 - 0x80000000 as un-cached memory. All buffers shared
> >> + * between the GMU and the CPU will live in this space
> >> + */
> >> + gmu->uncached_iova_base = 0x60000000;
> >> +
> >> +
> >> + gmu->domain = iommu_domain_alloc(&platform_bus_type);
> >> + if (!gmu->domain)
> >> + return -ENODEV;
> >> +
> >> + ret = iommu_attach_device(gmu->domain, gmu->dev);
> >> +
> >> + if (ret) {
> >> + iommu_domain_free(gmu->domain);
> >> + gmu->domain = NULL;
> >> + }
> >> +
> >> + return ret;
> >> }
> >>
> >> /* Return the 'arc-level' for the given frequency */
> >> @@ -1206,6 +1289,10 @@ void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu)
> >>
> >> a6xx_gmu_memory_free(gmu, gmu->hfi);
> >>
> >> + iommu_detach_device(gmu->domain, gmu->dev);
> >> +
> >> + iommu_domain_free(gmu->domain);
> >> +
> >> free_irq(gmu->gmu_irq, gmu);
> >> free_irq(gmu->hfi_irq, gmu);
> >>
> >> @@ -1226,15 +1313,7 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
> >>
> >> gmu->dev = &pdev->dev;
> >>
> >> - /* Pass force_dma false to require the DT to set the dma region */
> >> - ret = of_dma_configure(gmu->dev, node, false);
> >> - if (ret)
> >> - return ret;
> >> -
> >> - /* Set the mask after the of_dma_configure() */
> >> - ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(31));
> >> - if (ret)
> >> - return ret;
> >> + of_dma_configure(gmu->dev, node, true);
> >>
> >> /* Fow now, don't do anything fancy until we get our feet under us */
> >> gmu->idle_level = GMU_IDLE_STATE_ACTIVE;
> >> @@ -1246,6 +1325,11 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
> >> if (ret)
> >> goto err_put_device;
> >>
> >> + /* Set up the IOMMU context bank */
> >> + ret = a6xx_gmu_memory_probe(gmu);
> >> + if (ret)
> >> + goto err_put_device;
> >> +
> >> /* Allocate memory for for the HFI queues */
> >> gmu->hfi = a6xx_gmu_memory_alloc(gmu, SZ_16K);
> >> if (IS_ERR(gmu->hfi))
> >> @@ -1291,6 +1375,11 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
> >> err_memory:
> >> a6xx_gmu_memory_free(gmu, gmu->hfi);
> >>
> >> + if (gmu->domain) {
> >> + iommu_detach_device(gmu->domain, gmu->dev);
> >> +
> >> + iommu_domain_free(gmu->domain);
> >> + }
> >> ret = -ENODEV;
> >>
> >> err_put_device:
> >> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
> >> index 4af65a36d5ca..2af91ed7ed0c 100644
> >> --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
> >> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
> >> @@ -12,7 +12,8 @@
> >> struct a6xx_gmu_bo {
> >> void *virt;
> >> size_t size;
> >> - dma_addr_t iova;
> >> + u64 iova;
> >> + struct page **pages;
> >> };
> >>
> >> /*
> >> @@ -48,6 +49,9 @@ struct a6xx_gmu {
> >> int hfi_irq;
> >> int gmu_irq;
> >>
> >> + struct iommu_domain *domain;
> >> + u64 uncached_iova_base;
> >> +
> >> struct device *gxpd;
> >>
> >> int idle_level;
> >> --
> >> 2.26.1
> >>