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-rw-r--r--drivers/spi/spi-s3c64xx.c14
-rw-r--r--drivers/spi/spi.c101
-rw-r--r--include/linux/spi/spi.h7
3 files changed, 94 insertions, 28 deletions
diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index e515b8a6f590..25c9bd409a87 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -381,7 +381,7 @@ static void s3c64xx_spi_dma_stop(struct s3c64xx_spi_driver_data *sdd,
#else
static void prepare_dma(struct s3c64xx_spi_dma_data *dma,
- unsigned len, dma_addr_t buf)
+ struct sg_table *sgt)
{
struct s3c64xx_spi_driver_data *sdd;
struct dma_slave_config config;
@@ -407,8 +407,8 @@ static void prepare_dma(struct s3c64xx_spi_dma_data *dma,
dmaengine_slave_config(dma->ch, &config);
}
- desc = dmaengine_prep_slave_single(dma->ch, buf, len,
- dma->direction, DMA_PREP_INTERRUPT);
+ desc = dmaengine_prep_slave_sg(dma->ch, sgt->sgl, sgt->nents,
+ dma->direction, DMA_PREP_INTERRUPT);
desc->callback = s3c64xx_spi_dmacb;
desc->callback_param = dma;
@@ -515,7 +515,11 @@ static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
chcfg |= S3C64XX_SPI_CH_TXCH_ON;
if (dma_mode) {
modecfg |= S3C64XX_SPI_MODE_TXDMA_ON;
+#ifndef CONFIG_S3C_DMA
+ prepare_dma(&sdd->tx_dma, &xfer->tx_sg);
+#else
prepare_dma(&sdd->tx_dma, xfer->len, xfer->tx_dma);
+#endif
} else {
switch (sdd->cur_bpw) {
case 32:
@@ -547,7 +551,11 @@ static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
| S3C64XX_SPI_PACKET_CNT_EN,
regs + S3C64XX_SPI_PACKET_CNT);
+#ifndef CONFIG_S3C_DMA
+ prepare_dma(&sdd->rx_dma, &xfer->rx_sg);
+#else
prepare_dma(&sdd->rx_dma, xfer->len, xfer->rx_dma);
+#endif
}
}
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.
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 31a5b0ee93ec..0c23c835d48b 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -24,6 +24,7 @@
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/completion.h>
+#include <linux/scatterlist.h>
struct dma_chan;
@@ -268,6 +269,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
* @auto_runtime_pm: the core should ensure a runtime PM reference is held
* while the hardware is prepared, using the parent
* device for the spidev
+ * @max_dma_len: Maximum length of a DMA transfer for the device.
* @prepare_transfer_hardware: a message will soon arrive from the queue
* so the subsystem requests the driver to prepare the transfer hardware
* by issuing this call
@@ -421,6 +423,7 @@ struct spi_master {
bool cur_msg_prepared;
bool cur_msg_mapped;
struct completion xfer_completion;
+ size_t max_dma_len;
int (*prepare_transfer_hardware)(struct spi_master *master);
int (*transfer_one_message)(struct spi_master *master,
@@ -533,6 +536,8 @@ extern struct spi_master *spi_busnum_to_master(u16 busnum);
* (optionally) changing the chipselect status, then starting
* the next transfer or completing this @spi_message.
* @transfer_list: transfers are sequenced through @spi_message.transfers
+ * @tx_sg: Scatterlist for transmit, currently not for client use
+ * @rx_sg: Scatterlist for receive, currently not for client use
*
* SPI transfers always write the same number of bytes as they read.
* Protocol drivers should always provide @rx_buf and/or @tx_buf.
@@ -600,6 +605,8 @@ struct spi_transfer {
dma_addr_t tx_dma;
dma_addr_t rx_dma;
+ struct sg_table tx_sg;
+ struct sg_table rx_sg;
unsigned cs_change:1;
unsigned tx_nbits:3;
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-17 17:58:50 +0000