linux-kernel - [PATCH 5/7] drm/etnaviv: prepare for shared

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Message-ID: <20250816074757.2559055-6-uwu@icenowy.me>
Date: Sat, 16 Aug 2025 15:47:55 +0800
From: Icenowy Zheng <uwu@...nowy.me>
To: Drew Fustini <fustini@...nel.org>,
	Guo Ren <guoren@...nel.org>,
	Fu Wei <wefu@...hat.com>,
	Lucas Stach <l.stach@...gutronix.de>,
	Russell King <linux+etnaviv@...linux.org.uk>,
	Christian Gmeiner <christian.gmeiner@...il.com>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>
Cc: linux-riscv@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	etnaviv@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org,
	Icenowy Zheng <uwu@...nowy.me>
Subject: [PATCH 5/7] drm/etnaviv: prepare for shared_context support for iommuv2

As we have some unfortunate GPUs with IOMMUv2 but broken PTA (reloading
a different page table at runtime always fails), shared_context is now
not a v1-only thing.

Move it out of the v1 struct in the union.

Signed-off-by: Icenowy Zheng <uwu@...nowy.me>
---
 drivers/gpu/drm/etnaviv/etnaviv_iommu.c |  8 ++++----
 drivers/gpu/drm/etnaviv/etnaviv_mmu.h   | 22 +++++++---------------
 2 files changed, 11 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_iommu.c b/drivers/gpu/drm/etnaviv/etnaviv_iommu.c
index afe5dd6a9925b..6fdce63b9971a 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_iommu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_iommu.c
@@ -39,7 +39,7 @@ static void etnaviv_iommuv1_free(struct etnaviv_iommu_context *context)
 	dma_free_wc(context->global->dev, PT_SIZE, v1_context->pgtable_cpu,
 		    v1_context->pgtable_dma);
 
-	context->global->v1.shared_context = NULL;
+	context->global->shared_context = NULL;
 
 	kfree(v1_context);
 }
@@ -136,8 +136,8 @@ etnaviv_iommuv1_context_alloc(struct etnaviv_iommu_global *global)
 	 * a stop the world operation, so we only support a single shared
 	 * context with this version.
 	 */
-	if (global->v1.shared_context) {
-		context = global->v1.shared_context;
+	if (global->shared_context) {
+		context = global->shared_context;
 		etnaviv_iommu_context_get(context);
 		mutex_unlock(&global->lock);
 		return context;
@@ -163,7 +163,7 @@ etnaviv_iommuv1_context_alloc(struct etnaviv_iommu_global *global)
 	mutex_init(&context->lock);
 	INIT_LIST_HEAD(&context->mappings);
 	drm_mm_init(&context->mm, GPU_MEM_START, PT_ENTRIES * SZ_4K);
-	context->global->v1.shared_context = context;
+	context->global->shared_context = context;
 
 	mutex_unlock(&global->lock);
 
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_mmu.h b/drivers/gpu/drm/etnaviv/etnaviv_mmu.h
index 7f8ac01785474..2ec4acda02bc6 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_mmu.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_mmu.h
@@ -49,21 +49,13 @@ struct etnaviv_iommu_global {
 
 	u32 memory_base;
 
-	/*
-	 * This union holds members needed by either MMUv1 or MMUv2, which
-	 * can not exist at the same time.
-	 */
-	union {
-		struct {
-			struct etnaviv_iommu_context *shared_context;
-		} v1;
-		struct {
-			/* P(age) T(able) A(rray) */
-			u64 *pta_cpu;
-			dma_addr_t pta_dma;
-			DECLARE_BITMAP(pta_alloc, ETNAVIV_PTA_ENTRIES);
-		} v2;
-	};
+	struct etnaviv_iommu_context *shared_context;
+	struct {
+		/* P(age) T(able) A(rray) */
+		u64 *pta_cpu;
+		dma_addr_t pta_dma;
+		DECLARE_BITMAP(pta_alloc, ETNAVIV_PTA_ENTRIES);
+	} v2;
 };
 
 struct etnaviv_iommu_context {
-- 
2.50.1