1 files changed, 76 insertions, 25 deletions

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index bb7cf561c311..49313dd0a144 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -582,13 +582,70 @@ static void spi_set_cs(struct spi_device *spi, bool enable)
                 spi->master->set_cs(spi, !enable);
 }
 
+static int spi_map_buf(struct spi_master *master, struct device *dev,
+                       struct sg_table *sgt, void *buf, size_t len,
+                       enum dma_data_direction dir)
+{
+        const bool vmalloced_buf = is_vmalloc_addr(buf);
+        const int desc_len = vmalloced_buf ? PAGE_SIZE : master->max_dma_len;
+        const int sgs = DIV_ROUND_UP(len, desc_len);
+        struct page *vm_page;
+        void *sg_buf;
+        size_t min;
+        int i, ret;
+
+        ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
+        if (ret != 0)
+                return ret;
+
+        for (i = 0; i < sgs; i++) {
+                min = min_t(size_t, len, desc_len);
+
+                if (vmalloced_buf) {
+                        vm_page = vmalloc_to_page(buf);
+                        if (!vm_page) {
+                                sg_free_table(sgt);
+                                return -ENOMEM;
+                        }
+                        sg_buf = page_address(vm_page) +
+                                ((size_t)buf & ~PAGE_MASK);
+                } else {
+                        sg_buf = buf;
+                }
+
+                sg_set_buf(&sgt->sgl[i], sg_buf, min);
+
+                buf += min;
+                len -= min;
+        }
+
+        ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
+        if (ret < 0) {
+                sg_free_table(sgt);
+                return ret;
+        }
+
+        sgt->nents = ret;
+
+        return 0;
+}
+
+static void spi_unmap_buf(struct spi_master *master, struct device *dev,
+                          struct sg_table *sgt, enum dma_data_direction dir)
+{
+        if (sgt->orig_nents) {
+                dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
+                sg_free_table(sgt);
+        }
+}
+
 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
 {
-        struct device *dev = master->dev.parent;
         struct device *tx_dev, *rx_dev;
         struct spi_transfer *xfer;
         void *tmp;
         size_t max_tx, max_rx;
+        int ret;
 
         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
                 max_tx = 0;
@@ -631,7 +688,7 @@ static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
                 }
         }
 
-        if (msg->is_dma_mapped || !master->can_dma)
+        if (!master->can_dma)
                 return 0;
 
         tx_dev = &master->dma_tx->dev->device;
@@ -642,25 +699,21 @@ static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
                         continue;
 
                 if (xfer->tx_buf != NULL) {
-                        xfer->tx_dma = dma_map_single(tx_dev,
-                                                      (void *)xfer->tx_buf,
-                                                      xfer->len,
-                                                      DMA_TO_DEVICE);
-                        if (dma_mapping_error(dev, xfer->tx_dma)) {
-                                dev_err(dev, "dma_map_single Tx failed\n");
-                                return -ENOMEM;
-                        }
+                        ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
+                                          (void *)xfer->tx_buf, xfer->len,
+                                          DMA_TO_DEVICE);
+                        if (ret != 0)
+                                return ret;
                 }
 
                 if (xfer->rx_buf != NULL) {
-                        xfer->rx_dma = dma_map_single(rx_dev,
-                                                      xfer->rx_buf, xfer->len,
-                                                      DMA_FROM_DEVICE);
-                        if (dma_mapping_error(dev, xfer->rx_dma)) {
-                                dev_err(dev, "dma_map_single Rx failed\n");
-                                dma_unmap_single(tx_dev, xfer->tx_dma,
-                                                 xfer->len, DMA_TO_DEVICE);
-                                return -ENOMEM;
+                        ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
+                                          xfer->rx_buf, xfer->len,
+                                          DMA_FROM_DEVICE);
+                        if (ret != 0) {
+                                spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
+                                              DMA_TO_DEVICE);
+                                return ret;
                         }
                 }
         }
@@ -675,7 +728,7 @@ static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
         struct spi_transfer *xfer;
         struct device *tx_dev, *rx_dev;
 
-        if (!master->cur_msg_mapped || msg->is_dma_mapped || !master->can_dma)
+        if (!master->cur_msg_mapped || !master->can_dma)
                 return 0;
 
         tx_dev = &master->dma_tx->dev->device;
@@ -685,12 +738,8 @@ static int spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
                 if (!master->can_dma(master, msg->spi, xfer))
                         continue;
 
-                if (xfer->rx_buf)
-                        dma_unmap_single(rx_dev, xfer->rx_dma, xfer->len,
-                                         DMA_FROM_DEVICE);
-                if (xfer->tx_buf)
-                        dma_unmap_single(tx_dev, xfer->tx_dma, xfer->len,
-                                         DMA_TO_DEVICE);
+                spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
+                spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
         }
 
         return 0;
@@ -1503,6 +1552,8 @@ int spi_register_master(struct spi_master *master)
         mutex_init(&master->bus_lock_mutex);
         master->bus_lock_flag = 0;
         init_completion(&master->xfer_completion);
+        if (!master->max_dma_len)
+                master->max_dma_len = INT_MAX;
 
         /* register the device, then userspace will see it.
          * registration fails if the bus ID is in use.