Add a new getter, get_io_tlb_mem, to help select the io_tlb_mem struct.
The restricted DMA pool is preferred if available.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 include/linux/swiotlb.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 03ad6e3b4056..b469f04cca26 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -2,6 +2,7 @@
 #ifndef __LINUX_SWIOTLB_H
 #define __LINUX_SWIOTLB_H
 
+#include <linux/device.h>
 #include <linux/dma-direction.h>
 #include <linux/init.h>
 #include <linux/types.h>
@@ -102,6 +103,16 @@ struct io_tlb_mem {
 };
 extern struct io_tlb_mem *io_tlb_default_mem;
 
+static inline struct io_tlb_mem *get_io_tlb_mem(struct device *dev)
+{
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+	if (dev && dev->dma_io_tlb_mem)
+		return dev->dma_io_tlb_mem;
+#endif /* CONFIG_DMA_RESTRICTED_POOL */
+
+	return io_tlb_default_mem;
+}
+
 static inline bool is_swiotlb_buffer(phys_addr_t paddr)
 {
 	struct io_tlb_mem *mem = io_tlb_default_mem;
-- 
2.31.1.607.g51e8a6a459-goog

> +static inline struct io_tlb_mem *get_io_tlb_mem(struct device *dev)
> +{
> +#ifdef CONFIG_DMA_RESTRICTED_POOL
> +	if (dev && dev->dma_io_tlb_mem)
> +		return dev->dma_io_tlb_mem;
> +#endif /* CONFIG_DMA_RESTRICTED_POOL */
> +
> +	return io_tlb_default_mem;

Given that we're also looking into a not addressing restricted pool
I'd rather always assign the active pool to dev->dma_io_tlb_mem and
do away with this helper.

On Mon, May 10, 2021 at 11:03 PM Christoph Hellwig <hch@lst.de> wrote:
>
> > +static inline struct io_tlb_mem *get_io_tlb_mem(struct device *dev)
> > +{
> > +#ifdef CONFIG_DMA_RESTRICTED_POOL
> > +     if (dev && dev->dma_io_tlb_mem)
> > +             return dev->dma_io_tlb_mem;
> > +#endif /* CONFIG_DMA_RESTRICTED_POOL */
> > +
> > +     return io_tlb_default_mem;
>
> Given that we're also looking into a not addressing restricted pool
> I'd rather always assign the active pool to dev->dma_io_tlb_mem and
> do away with this helper.

Where do you think is the proper place to do the assignment? First
time calling swiotlb_map? or in of_dma_configure_id?