From dffc12a8195a5cf83819f38cd68a10b3f32ed1bd Mon Sep 17 00:00:00 2001
From: mmel <mmel@FreeBSD.org>
Date: Wed, 18 Nov 2015 16:07:01 +0000
Subject: ARM: Fix dma_dcache_sync() for early allocated memory. Drivers can
 request DMA to buffers that are not in memory represented in the vm page
 arrays. Because of this, store KVA of already mapped buffer to synclist and
 use it in dma_dcache_sync().

Reviewed by:	jah
Approved by:	kib (mentor)
Differential Revision: https://reviews.freebsd.org/D4120
---
 sys/arm/arm/busdma_machdep-v6.c | 35 ++++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/sys/arm/arm/busdma_machdep-v6.c b/sys/arm/arm/busdma_machdep-v6.c
index a755740..fe446b9 100644
--- a/sys/arm/arm/busdma_machdep-v6.c
+++ b/sys/arm/arm/busdma_machdep-v6.c
@@ -117,8 +117,8 @@ struct bounce_page {
 
 struct sync_list {
 	vm_offset_t	vaddr;		/* kva of client data */
+	bus_addr_t	paddr;		/* physical address */
 	vm_page_t	pages;		/* starting page of client data */
-	vm_offset_t	dataoffs;	/* page offset of client data */
 	bus_size_t	datacount;	/* client data count */
 };
 
@@ -1076,17 +1076,19 @@ _bus_dmamap_load_phys(bus_dma_tag_t dmat, bus_dmamap_t map, vm_paddr_t buf,
 			    sgsize);
 		} else {
 			if (map->sync_count > 0)
-				sl_end = VM_PAGE_TO_PHYS(sl->pages) +
-				    sl->dataoffs + sl->datacount;
+				sl_end = sl->paddr + sl->datacount;
 
 			if (map->sync_count == 0 || curaddr != sl_end) {
 				if (++map->sync_count > dmat->nsegments)
 					break;
 				sl++;
 				sl->vaddr = 0;
+				sl->paddr = curaddr;
 				sl->datacount = sgsize;
 				sl->pages = PHYS_TO_VM_PAGE(curaddr);
-				sl->dataoffs = curaddr & PAGE_MASK;
+				KASSERT(sl->pages != NULL,
+				    ("%s: page at PA:0x%08lx is not in "
+				    "vm_page_array", __func__, curaddr));
 			} else
 				sl->datacount += sgsize;
 		}
@@ -1188,8 +1190,7 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 			    sgsize);
 		} else {
 			if (map->sync_count > 0) {
-				sl_pend = VM_PAGE_TO_PHYS(sl->pages) +
-				    sl->dataoffs + sl->datacount;
+				sl_pend = sl->paddr + sl->datacount;
 				sl_vend = sl->vaddr + sl->datacount;
 			}
 
@@ -1201,9 +1202,17 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 					goto cleanup;
 				sl++;
 				sl->vaddr = kvaddr;
+				sl->paddr = curaddr;
+				if (kvaddr != 0) {
+					sl->pages = NULL;
+				} else {
+					sl->pages = PHYS_TO_VM_PAGE(curaddr);
+					KASSERT(sl->pages != NULL,
+					    ("%s: page at PA:0x%08lx is not "
+					    "in vm_page_array", __func__,
+					    curaddr));
+				}
 				sl->datacount = sgsize;
-				sl->pages = PHYS_TO_VM_PAGE(curaddr);
-				sl->dataoffs = curaddr & PAGE_MASK;
 			} else
 				sl->datacount += sgsize;
 		}
@@ -1299,10 +1308,10 @@ dma_dcache_sync(struct sync_list *sl, bus_dmasync_op_t op)
 	vm_offset_t va, tempva;
 	bus_size_t size;
 
-	offset = sl->dataoffs;
+	offset = sl->paddr & PAGE_MASK;
 	m = sl->pages;
 	size = sl->datacount;
-	pa = VM_PAGE_TO_PHYS(m) | offset;
+	pa = sl->paddr;
 
 	for ( ; size != 0; size -= len, pa += len, offset = 0, ++m) {
 		tempva = 0;
@@ -1310,13 +1319,13 @@ dma_dcache_sync(struct sync_list *sl, bus_dmasync_op_t op)
 			len = min(PAGE_SIZE - offset, size);
 			tempva = pmap_quick_enter_page(m);
 			va = tempva | offset;
+			KASSERT(pa == (VM_PAGE_TO_PHYS(m) | offset),
+			    ("unexpected vm_page_t phys: 0x%08x != 0x%08x",
+			    VM_PAGE_TO_PHYS(m) | offset, pa));
 		} else {
 			len = sl->datacount;
 			va = sl->vaddr;
 		}
-		KASSERT(pa == (VM_PAGE_TO_PHYS(m) | offset),
-		    ("unexpected vm_page_t phys: 0x%08x != 0x%08x",
-		    VM_PAGE_TO_PHYS(m) | offset, pa));
 
 		switch (op) {
 		case BUS_DMASYNC_PREWRITE:
-- 
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