diff options
| author | Vignesh R | 2016-06-08 12:18:31 +0530 |
|---|---|---|
| committer | Mark Brown | 2016-06-08 10:26:46 +0100 |
| commit | f4502dd1da9b060a49d539eb754ff86cb97b89f0 (patch) | |
| tree | 257cf2635e5b8931b06e331f678490a71817100d | |
| parent | 1a695a905c18548062509178b98bc91e67510864 (diff) | |
spi: Add DMA support for spi_flash_read()
Few SPI devices provide accelerated read interfaces to read from
SPI-NOR flash devices. These hardwares also support DMA to transfer data
from flash to memory either via mem-to-mem DMA or dedicated slave DMA
channels. Hence, add support for DMA in order to improve throughput and
reduce CPU load.
Use spi_map_buf() to get sg table for the buffer and pass it to SPI
driver.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
| -rw-r--r-- | drivers/spi/spi.c | 28 | ||||
| -rw-r--r-- | include/linux/spi/spi.h | 4 |
2 files changed, 32 insertions, 0 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 77e6e45951f4..c9a8d544e467 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -849,6 +849,20 @@ static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg) return 0; } #else /* !CONFIG_HAS_DMA */ +static inline 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) +{ + return -EINVAL; +} + +static inline void spi_unmap_buf(struct spi_master *master, + struct device *dev, struct sg_table *sgt, + enum dma_data_direction dir) +{ +} + static inline int __spi_map_msg(struct spi_master *master, struct spi_message *msg) { @@ -2725,6 +2739,7 @@ int spi_flash_read(struct spi_device *spi, { struct spi_master *master = spi->master; + struct device *rx_dev = NULL; int ret; if ((msg->opcode_nbits == SPI_NBITS_DUAL || @@ -2750,9 +2765,22 @@ int spi_flash_read(struct spi_device *spi, return ret; } } + mutex_lock(&master->bus_lock_mutex); + if (master->dma_rx) { + rx_dev = master->dma_rx->device->dev; + ret = spi_map_buf(master, rx_dev, &msg->rx_sg, + msg->buf, msg->len, + DMA_FROM_DEVICE); + if (!ret) + msg->cur_msg_mapped = true; + } ret = master->spi_flash_read(spi, msg); + if (msg->cur_msg_mapped) + spi_unmap_buf(master, rx_dev, &msg->rx_sg, + DMA_FROM_DEVICE); mutex_unlock(&master->bus_lock_mutex); + if (master->auto_runtime_pm) pm_runtime_put(master->dev.parent); diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 1f03483f61e5..7b53af4ba5f8 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -1143,6 +1143,8 @@ static inline ssize_t spi_w8r16be(struct spi_device *spi, u8 cmd) * @opcode_nbits: number of lines to send opcode * @addr_nbits: number of lines to send address * @data_nbits: number of lines for data + * @rx_sg: Scatterlist for receive data read from flash + * @cur_msg_mapped: message has been mapped for DMA */ struct spi_flash_read_message { void *buf; @@ -1155,6 +1157,8 @@ struct spi_flash_read_message { u8 opcode_nbits; u8 addr_nbits; u8 data_nbits; + struct sg_table rx_sg; + bool cur_msg_mapped; }; /* SPI core interface for flash read support */ |