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path: root/drivers/spi/spi-davinci.c
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Diffstat (limited to 'drivers/spi/spi-davinci.c')
-rw-r--r--drivers/spi/spi-davinci.c95
1 files changed, 40 insertions, 55 deletions
diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
index 02fb96797ac8..595acdcfc7d0 100644
--- a/drivers/spi/spi-davinci.c
+++ b/drivers/spi/spi-davinci.c
@@ -109,6 +109,8 @@
#define SPIDEF 0x4c
#define SPIFMT0 0x50
+#define DMA_MIN_BYTES 16
+
/* SPI Controller driver's private data. */
struct davinci_spi {
struct spi_bitbang bitbang;
@@ -389,6 +391,7 @@ static int davinci_spi_of_setup(struct spi_device *spi)
{
struct davinci_spi_config *spicfg = spi->controller_data;
struct device_node *np = spi->dev.of_node;
+ struct davinci_spi *dspi = spi_master_get_devdata(spi->master);
u32 prop;
if (spicfg == NULL && np) {
@@ -400,6 +403,9 @@ static int davinci_spi_of_setup(struct spi_device *spi)
if (!of_property_read_u32(np, "ti,spi-wdelay", &prop))
spicfg->wdelay = (u8)prop;
spi->controller_data = spicfg;
+
+ if (dspi->dma_rx && dspi->dma_tx)
+ spicfg->io_type = SPI_IO_TYPE_DMA;
}
return 0;
@@ -467,6 +473,22 @@ static void davinci_spi_cleanup(struct spi_device *spi)
kfree(spicfg);
}
+static bool davinci_spi_can_dma(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *xfer)
+{
+ struct davinci_spi_config *spicfg = spi->controller_data;
+ bool can_dma = false;
+
+ if (spicfg)
+ can_dma = (spicfg->io_type == SPI_IO_TYPE_DMA) &&
+ (xfer->len >= DMA_MIN_BYTES) &&
+ !is_vmalloc_addr(xfer->rx_buf) &&
+ !is_vmalloc_addr(xfer->tx_buf);
+
+ return can_dma;
+}
+
static int davinci_spi_check_error(struct davinci_spi *dspi, int int_status)
{
struct device *sdev = dspi->bitbang.master->dev.parent;
@@ -581,8 +603,6 @@ static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
struct davinci_spi_config *spicfg;
struct davinci_spi_platform_data *pdata;
unsigned uninitialized_var(rx_buf_count);
- void *dummy_buf = NULL;
- struct scatterlist sg_rx, sg_tx;
dspi = spi_master_get_devdata(spi->master);
pdata = &dspi->pdata;
@@ -605,10 +625,9 @@ static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
reinit_completion(&dspi->done);
- if (spicfg->io_type == SPI_IO_TYPE_INTR)
- set_io_bits(dspi->base + SPIINT, SPIINT_MASKINT);
-
- if (spicfg->io_type != SPI_IO_TYPE_DMA) {
+ if (!davinci_spi_can_dma(spi->master, spi, t)) {
+ if (spicfg->io_type != SPI_IO_TYPE_POLL)
+ set_io_bits(dspi->base + SPIINT, SPIINT_MASKINT);
/* start the transfer */
dspi->wcount--;
tx_data = dspi->get_tx(dspi);
@@ -630,51 +649,28 @@ static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
};
struct dma_async_tx_descriptor *rxdesc;
struct dma_async_tx_descriptor *txdesc;
- void *buf;
-
- dummy_buf = kzalloc(t->len, GFP_KERNEL);
- if (!dummy_buf)
- goto err_alloc_dummy_buf;
dmaengine_slave_config(dspi->dma_rx, &dma_rx_conf);
dmaengine_slave_config(dspi->dma_tx, &dma_tx_conf);
- sg_init_table(&sg_rx, 1);
- if (!t->rx_buf)
- buf = dummy_buf;
- else
- buf = t->rx_buf;
- t->rx_dma = dma_map_single(&spi->dev, buf,
- t->len, DMA_FROM_DEVICE);
- if (dma_mapping_error(&spi->dev, !t->rx_dma)) {
- ret = -EFAULT;
- goto err_rx_map;
- }
- sg_dma_address(&sg_rx) = t->rx_dma;
- sg_dma_len(&sg_rx) = t->len;
-
- sg_init_table(&sg_tx, 1);
- if (!t->tx_buf)
- buf = dummy_buf;
- else
- buf = (void *)t->tx_buf;
- t->tx_dma = dma_map_single(&spi->dev, buf,
- t->len, DMA_TO_DEVICE);
- if (dma_mapping_error(&spi->dev, t->tx_dma)) {
- ret = -EFAULT;
- goto err_tx_map;
- }
- sg_dma_address(&sg_tx) = t->tx_dma;
- sg_dma_len(&sg_tx) = t->len;
-
rxdesc = dmaengine_prep_slave_sg(dspi->dma_rx,
- &sg_rx, 1, DMA_DEV_TO_MEM,
+ t->rx_sg.sgl, t->rx_sg.nents, DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!rxdesc)
goto err_desc;
+ if (!t->tx_buf) {
+ /* To avoid errors when doing rx-only transfers with
+ * many SG entries (> 20), use the rx buffer as the
+ * dummy tx buffer so that dma reloads are done at the
+ * same time for rx and tx.
+ */
+ t->tx_sg.sgl = t->rx_sg.sgl;
+ t->tx_sg.nents = t->rx_sg.nents;
+ }
+
txdesc = dmaengine_prep_slave_sg(dspi->dma_tx,
- &sg_tx, 1, DMA_MEM_TO_DEV,
+ t->tx_sg.sgl, t->tx_sg.nents, DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!txdesc)
goto err_desc;
@@ -710,16 +706,9 @@ static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
}
clear_io_bits(dspi->base + SPIINT, SPIINT_MASKALL);
- if (spicfg->io_type == SPI_IO_TYPE_DMA) {
+ if (davinci_spi_can_dma(spi->master, spi, t))
clear_io_bits(dspi->base + SPIINT, SPIINT_DMA_REQ_EN);
- dma_unmap_single(&spi->dev, t->rx_dma,
- t->len, DMA_FROM_DEVICE);
- dma_unmap_single(&spi->dev, t->tx_dma,
- t->len, DMA_TO_DEVICE);
- kfree(dummy_buf);
- }
-
clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
@@ -742,12 +731,6 @@ static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
return t->len;
err_desc:
- dma_unmap_single(&spi->dev, t->tx_dma, t->len, DMA_TO_DEVICE);
-err_tx_map:
- dma_unmap_single(&spi->dev, t->rx_dma, t->len, DMA_FROM_DEVICE);
-err_rx_map:
- kfree(dummy_buf);
-err_alloc_dummy_buf:
return ret;
}
@@ -988,8 +971,10 @@ static int davinci_spi_probe(struct platform_device *pdev)
master->bus_num = pdev->id;
master->num_chipselect = pdata->num_chipselect;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 16);
+ master->flags = SPI_MASTER_MUST_RX;
master->setup = davinci_spi_setup;
master->cleanup = davinci_spi_cleanup;
+ master->can_dma = davinci_spi_can_dma;
dspi->bitbang.chipselect = davinci_spi_chipselect;
dspi->bitbang.setup_transfer = davinci_spi_setup_transfer;
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-17 09:38:42 +0000