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

[Jonathan Marek <jonathan@marek.ca>]

This reverts commit a5fb8b918920c6f7706a8b5b8ea535a7f077a7f6.
---
 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