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-rw-r--r--drivers/spi/spi.c82
-rw-r--r--include/linux/spi/spi.h18
2 files changed, 100 insertions, 0 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 23756b0f9036..bcdaa74f1c8e 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -24,6 +24,8 @@
#include <linux/device.h>
#include <linux/init.h>
#include <linux/cache.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
@@ -580,6 +582,77 @@ static void spi_set_cs(struct spi_device *spi, bool enable)
spi->master->set_cs(spi, !enable);
}
+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;
+
+ if (msg->is_dma_mapped || !master->can_dma)
+ return 0;
+
+ tx_dev = &master->dma_tx->dev->device;
+ rx_dev = &master->dma_rx->dev->device;
+
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ if (!master->can_dma(master, msg->spi, xfer))
+ 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;
+ }
+ }
+
+ 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;
+ }
+ }
+ }
+
+ master->cur_msg_mapped = true;
+
+ return 0;
+}
+
+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)
+ return 0;
+
+ tx_dev = &master->dma_tx->dev->device;
+ rx_dev = &master->dma_rx->dev->device;
+
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ 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);
+ }
+
+ return 0;
+}
+
/*
* spi_transfer_one_message - Default implementation of transfer_one_message()
*
@@ -752,6 +825,13 @@ static void spi_pump_messages(struct kthread_work *work)
master->cur_msg_prepared = true;
}
+ ret = spi_map_msg(master, master->cur_msg);
+ if (ret) {
+ master->cur_msg->status = ret;
+ spi_finalize_current_message(master);
+ return;
+ }
+
ret = master->transfer_one_message(master, master->cur_msg);
if (ret) {
dev_err(&master->dev,
@@ -841,6 +921,8 @@ void spi_finalize_current_message(struct spi_master *master)
queue_kthread_work(&master->kworker, &master->pump_messages);
spin_unlock_irqrestore(&master->queue_lock, flags);
+ spi_unmap_msg(master, mesg);
+
if (master->cur_msg_prepared && master->unprepare_message) {
ret = master->unprepare_message(master, mesg);
if (ret) {
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index a1d4ca290862..b354dcbed55b 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -25,6 +25,8 @@
#include <linux/kthread.h>
#include <linux/completion.h>
+struct dma_chan;
+
/*
* INTERFACES between SPI master-side drivers and SPI infrastructure.
* (There's no SPI slave support for Linux yet...)
@@ -387,6 +389,17 @@ struct spi_master {
void (*cleanup)(struct spi_device *spi);
/*
+ * Used to enable core support for DMA handling, if can_dma()
+ * exists and returns true then the transfer will be mapped
+ * prior to transfer_one() being called. The driver should
+ * not modify or store xfer and dma_tx and dma_rx must be set
+ * while the device is prepared.
+ */
+ bool (*can_dma)(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *xfer);
+
+ /*
* These hooks are for drivers that want to use the generic
* master transfer queueing mechanism. If these are used, the
* transfer() function above must NOT be specified by the driver.
@@ -404,6 +417,7 @@ struct spi_master {
bool rt;
bool auto_runtime_pm;
bool cur_msg_prepared;
+ bool cur_msg_mapped;
struct completion xfer_completion;
int (*prepare_transfer_hardware)(struct spi_master *master);
@@ -425,6 +439,10 @@ struct spi_master {
/* gpio chip select */
int *cs_gpios;
+
+ /* DMA channels for use with core dmaengine helpers */
+ struct dma_chan *dma_tx;
+ struct dma_chan *dma_rx;
};
static inline void *spi_master_get_devdata(struct spi_master *master)