From: Florian Fainelli <f.fainelli@gmail.com>
Date: Fri, 19 Mar 2021 04:03:33 +0000 (-0700)
Subject: ARM: Qualify enabling of swiotlb_init()
X-Git-Tag: baikal/aarch64/sdk5.9~6774
X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=2ef5eb848f862ede38e5a7cd3656b5501104acd7;p=kernel.git

ARM: Qualify enabling of swiotlb_init()

commit fcf044891c84e38fc90eb736b818781bccf94e38 upstream.

We do not need a SWIOTLB unless we have DRAM that is addressable beyond
the arm_dma_limit. Compare max_pfn with arm_dma_pfn_limit to determine
whether we do need a SWIOTLB to be initialized.

Fixes: 96ea560103b0 ("arm: use swiotlb for bounce buffering on LPAE configs")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 0804a6af4a3b7..5a3641b5ec2cd 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -469,7 +469,11 @@ static void __init free_highpages(void)
 void __init mem_init(void)
 {
 #ifdef CONFIG_ARM_LPAE
-	swiotlb_init(1);
+	if (swiotlb_force == SWIOTLB_FORCE ||
+	    max_pfn > arm_dma_pfn_limit)
+		swiotlb_init(1);
+	else
+		swiotlb_force = SWIOTLB_NO_FORCE;
 #endif
 
 	set_max_mapnr(pfn_to_page(max_pfn) - mem_map);