Add samsung specific changes

kernel/dma/Kconfig

@@ -120,6 +120,18 @@ config DMA_RESTRICTED_POOL
 	  and <kernel/dma/swiotlb.c>.
 	  If unsure, say "n".
 
+config SWIOTLB_NONLINEAR
+	bool "Allow swiotlb to use non-linear memory as bounce buffers"
+	depends on SWIOTLB
+	help
+	  This allows swiotlb driver to work with memory regions where
+	  physical to virtual address translations can't be done using APIs
+	  such as phys_to_virt. These could be reserved memory regions that
+	  are not mapped by default or could be seen as "device" memory
+	  accessed via ioremap().
+
+	  If unsure, say "n".
+
 #
 # Should be selected if we can mmap non-coherent mappings to userspace.
 # The only thing that is really required is a way to set an uncached bit

kernel/dma/swiotlb.c

@@ -96,6 +96,16 @@ static struct io_tlb_mem io_tlb_default_mem;
 
 #endif	/* CONFIG_SWIOTLB_DYNAMIC */
 
+#ifdef CONFIG_SWIOTLB_NONLINEAR
+phys_addr_t io_tlb_start, io_tlb_end;
+static unsigned long io_tlb_nslabs;
+static char *io_tlb_vstart;
+
+static inline unsigned char *swiotlb_phys_to_virt(phys_addr_t tlb_addr);
+#else
+#define swiotlb_phys_to_virt phys_to_virt
+#endif
+
 static unsigned long default_nslabs = IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT;
 static unsigned long default_nareas;
 
@@ -266,7 +276,7 @@ void __init swiotlb_update_mem_attributes(void)
 static void swiotlb_init_io_tlb_pool(struct io_tlb_pool *mem, phys_addr_t start,
 		unsigned long nslabs, bool late_alloc, unsigned int nareas)
 {
-	void *vaddr = phys_to_virt(start);
+	void *vaddr = swiotlb_phys_to_virt(start);
 	unsigned long bytes = nslabs << IO_TLB_SHIFT, i;
 
 	mem->nslabs = nslabs;
@@ -518,6 +528,63 @@ error_area:
 	return -ENOMEM;
 }
 
+#ifdef CONFIG_SWIOTLB_NONLINEAR
+static int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
+{
+	struct io_tlb_pool *mem = &io_tlb_default_mem.defpool;
+	unsigned long bytes = nslabs << IO_TLB_SHIFT;
+	unsigned int area_order;
+
+	/* protect against double initialization */
+	if (WARN_ON_ONCE(mem->nslabs))
+		return -ENOMEM;
+
+	if (!default_nareas)
+		swiotlb_adjust_nareas(num_possible_cpus());
+
+	area_order = get_order(array_size(sizeof(*mem->areas),
+		default_nareas));
+	mem->areas = (struct io_tlb_area *)
+		__get_free_pages(GFP_KERNEL | __GFP_ZERO, area_order);
+	if (!mem->areas)
+		return -ENOMEM;
+
+	mem->slots = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+		get_order(array_size(sizeof(*mem->slots), nslabs)));
+	if (!mem->slots)
+		goto error_slots;
+
+	set_memory_decrypted((unsigned long)tlb, bytes >> PAGE_SHIFT);
+	swiotlb_init_io_tlb_pool(mem, io_tlb_start, nslabs, true, default_nareas);
+	add_mem_pool(&io_tlb_default_mem, mem);
+
+	swiotlb_print_info();
+	return 0;
+
+error_slots:
+	free_pages((unsigned long)mem->areas, area_order);
+	return -ENOMEM;
+}
+
+int swiotlb_late_init_with_tblpaddr(char *tlb,
+			phys_addr_t tlb_paddr, unsigned long nslabs)
+{
+	unsigned long bytes;
+
+	if (io_tlb_start)
+		return -EBUSY;
+
+	bytes = nslabs << IO_TLB_SHIFT;
+	io_tlb_nslabs = nslabs;
+	io_tlb_start = tlb_paddr;
+	io_tlb_vstart = tlb;
+	io_tlb_end = io_tlb_start + bytes;
+
+	return swiotlb_late_init_with_tbl(tlb, nslabs);
+}
+EXPORT_SYMBOL_GPL(swiotlb_late_init_with_tblpaddr);
+#endif	/* CONFIG_SWIOTLB_NONLINEAR */
+
 void __init swiotlb_exit(void)
 {
 	struct io_tlb_pool *mem = &io_tlb_default_mem.defpool;
@@ -829,6 +896,13 @@ static unsigned int swiotlb_align_offset(struct device *dev, u64 addr)
 	return addr & dma_get_min_align_mask(dev) & (IO_TLB_SIZE - 1);
 }
 
+#ifdef CONFIG_SWIOTLB_NONLINEAR
+static inline unsigned char *swiotlb_phys_to_virt(phys_addr_t tlb_addr)
+{
+	return (unsigned char *)(io_tlb_vstart + (tlb_addr - io_tlb_start));
+}
+#endif
+
 /*
  * Bounce: copy the swiotlb buffer from or back to the original dma location
  */
@@ -1431,6 +1505,10 @@ void swiotlb_tbl_unmap_single(struct device *dev, phys_addr_t tlb_addr,
 	swiotlb_release_slots(dev, tlb_addr);
 }
 
+#ifdef CONFIG_SWIOTLB_NONLINEAR
+EXPORT_SYMBOL_GPL(swiotlb_tbl_unmap_single);
+#endif
+
 void swiotlb_sync_single_for_device(struct device *dev, phys_addr_t tlb_addr,
 		size_t size, enum dma_data_direction dir)
 {
@@ -1481,6 +1559,15 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size,
 		arch_sync_dma_for_device(swiotlb_addr, size, dir);
 	return dma_addr;
 }
+#ifdef CONFIG_SWIOTLB_NONLINEAR
+EXPORT_SYMBOL_GPL(swiotlb_map);
+
+size_t swiotlb_max_mapping_size(struct device *dev)
+{
+	return 4096;
+}
+#else
+
 
 size_t swiotlb_max_mapping_size(struct device *dev)
 {
@@ -1497,6 +1584,7 @@ size_t swiotlb_max_mapping_size(struct device *dev)
 
 	return ((size_t)IO_TLB_SIZE) * IO_TLB_SEGSIZE - min_align;
 }
+#endif
 
 /**
  * is_swiotlb_allocated() - check if the default software IO TLB is initialized