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Subject[PATCH v3 3/4] swiotlb: make new {unmap,sync}_desc dma apis work with swiotlb
Date
From: Laurentiu Tudor <laurentiu.tudor@nxp.com>

Add a new swiotlb helper to retrieve the original physical
address given a swiotlb physical address and use it in the new
dma_unmap_single_attrs_desc(), dma_sync_single_for_cpu_desc() and
dma_unmap_page_attrs_desc() APIs to make them work with swiotlb.

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
---
include/linux/swiotlb.h | 7 +++++++
kernel/dma/mapping.c | 43 ++++++++++++++++++++++++++++++++---------
kernel/dma/swiotlb.c | 8 ++++++++
3 files changed, 49 insertions(+), 9 deletions(-)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index cde3dc18e21a..7a6883a71649 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -73,6 +73,8 @@ static inline bool is_swiotlb_buffer(phys_addr_t paddr)
return paddr >= io_tlb_start && paddr < io_tlb_end;
}

+phys_addr_t swiotlb_get_orig_phys(phys_addr_t tlb_addr);
+
bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,
size_t size, enum dma_data_direction dir, unsigned long attrs);
void __init swiotlb_exit(void);
@@ -85,6 +87,11 @@ static inline bool is_swiotlb_buffer(phys_addr_t paddr)
{
return false;
}
+
+static inline phys_addr_t swiotlb_get_orig_phys(phys_addr_t tlb_addr)
+{
+ return PHYS_ADDR_MAX;
+}
static inline bool swiotlb_map(struct device *dev, phys_addr_t *phys,
dma_addr_t *dma_addr, size_t size, enum dma_data_direction dir,
unsigned long attrs)
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 2b6f245c9bb1..1a2d02727271 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -14,6 +14,7 @@
#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
+#include <linux/swiotlb.h>

/*
* Managed DMA API
@@ -352,10 +353,18 @@ dma_unmap_page_attrs_desc(struct device *dev, dma_addr_t addr, size_t size,
const struct dma_map_ops *ops = get_dma_ops(dev);
void *ptr = NULL;

- if (dma_is_direct(ops))
- ptr = phys_to_virt(dma_to_phys(dev, addr));
- else if (ops && ops->get_virt_addr)
+ if (dma_is_direct(ops)) {
+ phys_addr_t phys = dma_to_phys(dev, addr);
+
+ if (is_swiotlb_buffer(phys)) {
+ phys = swiotlb_get_orig_phys(phys);
+ ptr = phys == PHYS_ADDR_MAX ? NULL : phys_to_virt(phys);
+ } else {
+ ptr = phys_to_virt(phys);
+ }
+ } else if (ops && ops->get_virt_addr) {
ptr = ops->get_virt_addr(dev, addr);
+ }

dma_unmap_page_attrs(dev, addr, size, dir, attrs);

@@ -370,10 +379,18 @@ void *dma_unmap_single_attrs_desc(struct device *dev, dma_addr_t addr,
const struct dma_map_ops *ops = get_dma_ops(dev);
void *ptr = NULL;

- if (dma_is_direct(ops))
- ptr = phys_to_virt(dma_to_phys(dev, addr));
- else if (ops && ops->get_virt_addr)
+ if (dma_is_direct(ops)) {
+ phys_addr_t phys = dma_to_phys(dev, addr);
+
+ if (is_swiotlb_buffer(phys)) {
+ phys = swiotlb_get_orig_phys(phys);
+ ptr = phys == PHYS_ADDR_MAX ? NULL : phys_to_virt(phys);
+ } else {
+ ptr = phys_to_virt(phys);
+ }
+ } else if (ops && ops->get_virt_addr) {
ptr = ops->get_virt_addr(dev, addr);
+ }

dma_unmap_single_attrs(dev, addr, size, dir, attrs);

@@ -387,10 +404,18 @@ void *dma_sync_single_for_cpu_desc(struct device *dev, dma_addr_t addr,
const struct dma_map_ops *ops = get_dma_ops(dev);
void *ptr = NULL;

- if (dma_is_direct(ops))
- ptr = phys_to_virt(dma_to_phys(dev, addr));
- else if (ops && ops->get_virt_addr)
+ if (dma_is_direct(ops)) {
+ phys_addr_t phys = dma_to_phys(dev, addr);
+
+ if (is_swiotlb_buffer(phys)) {
+ phys = swiotlb_get_orig_phys(phys);
+ ptr = phys == PHYS_ADDR_MAX ? NULL : phys_to_virt(phys);
+ } else {
+ ptr = phys_to_virt(phys);
+ }
+ } else if (ops && ops->get_virt_addr) {
ptr = ops->get_virt_addr(dev, addr);
+ }

dma_sync_single_for_cpu(dev, addr, size, dir);

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 673a2cdb2656..9b241cc0535b 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -701,6 +701,14 @@ bool is_swiotlb_active(void)
return io_tlb_end != 0;
}

+phys_addr_t swiotlb_get_orig_phys(phys_addr_t tlb_addr)
+{
+ int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
+ phys_addr_t phys = io_tlb_orig_addr[index];
+
+ return phys == INVALID_PHYS_ADDR ? PHYS_ADDR_MAX : phys;
+}
+
#ifdef CONFIG_DEBUG_FS

static int __init swiotlb_create_debugfs(void)
--
2.17.1
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