From 62f1089f3cbe7d99ced92bf96a8158813b75e5e8 Mon Sep 17 00:00:00 2001
From: Rob Herring <robh@kernel.org>
Date: Mon, 26 Aug 2019 17:33:16 -0500
Subject: drm/panfrost: Flush and disable address space when freeing page
 tables
Git-commit: 62f1089f3cbe7d99ced92bf96a8158813b75e5e8
Patch-mainline: v5.4-rc1
References: bsc#1152489

Currently, page tables are freed without disabling the address space first.
This probably is fine as we'll switch to new page tables when the address
space is allocated again and runtime PM suspend will reset the GPU
clearing the registers. However, it's better to clean up after ourselves.
There is also a problem that we could be accessing the h/w in
tlb_inv_context() when suspended.

Rework the disable code to make sure we flush caches/TLBs and disable the
address space before freeing the page tables if we are not suspended. As
the tlb_inv_context() hook is only called when freeing the page tables and
we do a flush before disabling the AS, lets remove the flush from
tlb_inv_context and avoid any runtime PM issues.

Fixes: 7282f7645d06 ("drm/panfrost: Implement per FD address spaces")
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190826223317.28509-8-robh@kernel.org
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/panfrost/panfrost_mmu.c |   16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -129,8 +129,10 @@ static void panfrost_mmu_enable(struct p
 	write_cmd(pfdev, as_nr, AS_COMMAND_UPDATE);
 }
 
-static void mmu_disable(struct panfrost_device *pfdev, u32 as_nr)
+static void panfrost_mmu_disable(struct panfrost_device *pfdev, u32 as_nr)
 {
+	mmu_hw_do_operation_locked(pfdev, as_nr, 0, ~0UL, AS_COMMAND_FLUSH_MEM);
+
 	mmu_write(pfdev, AS_TRANSTAB_LO(as_nr), 0);
 	mmu_write(pfdev, AS_TRANSTAB_HI(as_nr), 0);
 
@@ -321,11 +323,7 @@ void panfrost_mmu_unmap(struct panfrost_
 }
 
 static void mmu_tlb_inv_context_s1(void *cookie)
-{
-	struct panfrost_file_priv *priv = cookie;
-
-	mmu_hw_do_operation(priv->pfdev, &priv->mmu, 0, ~0UL, AS_COMMAND_FLUSH_MEM);
-}
+{}
 
 static void mmu_tlb_sync_context(void *cookie)
 {
@@ -382,6 +380,11 @@ void panfrost_mmu_pgtable_free(struct pa
 
 	spin_lock(&pfdev->as_lock);
 	if (mmu->as >= 0) {
+		pm_runtime_get_noresume(pfdev->dev);
+		if (pm_runtime_active(pfdev->dev))
+			panfrost_mmu_disable(pfdev, mmu->as);
+		pm_runtime_put_autosuspend(pfdev->dev);
+
 		clear_bit(mmu->as, &pfdev->as_alloc_mask);
 		clear_bit(mmu->as, &pfdev->as_in_use_mask);
 		list_del(&mmu->list);
@@ -626,5 +629,4 @@ int panfrost_mmu_init(struct panfrost_de
 void panfrost_mmu_fini(struct panfrost_device *pfdev)
 {
 	mmu_write(pfdev, MMU_INT_MASK, 0);
-	mmu_disable(pfdev, 0);
 }