Hi Russell:

On Wed, Jun 29, 2011 at 04:24:36PM +0800, Huang Shijie wrote:

quoted

+	dma_addr_t destination_phys = ~0;
+
+	if (virt_addr_valid(destination))
+		destination_phys = dma_map_single(dev, destination,
+						length, DMA_FROM_DEVICE);
+
+	if (dma_mapping_error(dev, destination_phys)) {

This is buggy.  There is no guarantee that we'll keep using ~0 as the
value for dma_mapping_error().  Please don't rely on this, but instead
code this better to avoid having to play these games.

thanks a lot. I will change it in the next version.

quoted

+static int send_page_prepare(struct gpmi_nfc_data *this,
+			const void *source, unsigned length,
+			void *alt_virt, dma_addr_t alt_phys, unsigned alt_size,
+			const void **use_virt, dma_addr_t *use_phys)
+{
+	dma_addr_t source_phys = ~0;
+	struct device *dev = this->dev;
+
+	if (virt_addr_valid(source))
+		source_phys = dma_map_single(dev,
+				(void *)source, length, DMA_TO_DEVICE);
+
+	if (dma_mapping_error(dev, source_phys)) {

Ditto.

Best Regards
Huang Shijie