spi: qup: Add DMA capabilities

This patch adds DMA capabilities to the spi-qup driver.  If DMA channels are
present, the QUP will use DMA instead of block mode for transfers to/from SPI
peripherals for transactions larger than the length of a block.

Signed-off-by: Andy Gross <agross@codeaurora.org>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Reviewed-by: Ivan T. Ivanov <iivanov@mm-sol.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Andy Gross 2015-03-04 12:02:05 +02:00 committed by Mark Brown
parent c517d838eb
commit 612762e82a
2 changed files with 312 additions and 32 deletions

View File

@ -33,6 +33,11 @@ Optional properties:
nodes. If unspecified, a single SPI device without a chip
select can be used.
- dmas: Two DMA channel specifiers following the convention outlined
in bindings/dma/dma.txt
- dma-names: Names for the dma channels, if present. There must be at
least one channel named "tx" for transmit and named "rx" for
receive.
SPI slave nodes must be children of the SPI master node and can contain
properties described in Documentation/devicetree/bindings/spi/spi-bus.txt
@ -51,6 +56,9 @@ Example:
clocks = <&gcc GCC_BLSP2_QUP2_SPI_APPS_CLK>, <&gcc GCC_BLSP2_AHB_CLK>;
clock-names = "core", "iface";
dmas = <&blsp1_bam 13>, <&blsp1_bam 12>;
dma-names = "rx", "tx";
pinctrl-names = "default";
pinctrl-0 = <&spi8_default>;

View File

@ -22,6 +22,8 @@
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/spi/spi.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#define QUP_CONFIG 0x0000
#define QUP_STATE 0x0004
@ -116,6 +118,8 @@
#define SPI_NUM_CHIPSELECTS 4
#define SPI_MAX_DMA_XFER (SZ_64K - 64)
/* high speed mode is when bus rate is greater then 26MHz */
#define SPI_HS_MIN_RATE 26000000
#define SPI_MAX_RATE 50000000
@ -140,9 +144,14 @@ struct spi_qup {
struct completion done;
int error;
int w_size; /* bytes per SPI word */
int n_words;
int tx_bytes;
int rx_bytes;
int qup_v1;
int use_dma;
struct dma_slave_config rx_conf;
struct dma_slave_config tx_conf;
};
@ -198,7 +207,6 @@ static int spi_qup_set_state(struct spi_qup *controller, u32 state)
return 0;
}
static void spi_qup_fifo_read(struct spi_qup *controller,
struct spi_transfer *xfer)
{
@ -266,6 +274,107 @@ static void spi_qup_fifo_write(struct spi_qup *controller,
}
}
static void spi_qup_dma_done(void *data)
{
struct spi_qup *qup = data;
complete(&qup->done);
}
static int spi_qup_prep_sg(struct spi_master *master, struct spi_transfer *xfer,
enum dma_transfer_direction dir,
dma_async_tx_callback callback)
{
struct spi_qup *qup = spi_master_get_devdata(master);
unsigned long flags = DMA_PREP_INTERRUPT | DMA_PREP_FENCE;
struct dma_async_tx_descriptor *desc;
struct scatterlist *sgl;
struct dma_chan *chan;
dma_cookie_t cookie;
unsigned int nents;
if (dir == DMA_MEM_TO_DEV) {
chan = master->dma_tx;
nents = xfer->tx_sg.nents;
sgl = xfer->tx_sg.sgl;
} else {
chan = master->dma_rx;
nents = xfer->rx_sg.nents;
sgl = xfer->rx_sg.sgl;
}
desc = dmaengine_prep_slave_sg(chan, sgl, nents, dir, flags);
if (!desc)
return -EINVAL;
desc->callback = callback;
desc->callback_param = qup;
cookie = dmaengine_submit(desc);
return dma_submit_error(cookie);
}
static void spi_qup_dma_terminate(struct spi_master *master,
struct spi_transfer *xfer)
{
if (xfer->tx_buf)
dmaengine_terminate_all(master->dma_tx);
if (xfer->rx_buf)
dmaengine_terminate_all(master->dma_rx);
}
static int spi_qup_do_dma(struct spi_master *master, struct spi_transfer *xfer)
{
dma_async_tx_callback rx_done = NULL, tx_done = NULL;
int ret;
if (xfer->rx_buf)
rx_done = spi_qup_dma_done;
else if (xfer->tx_buf)
tx_done = spi_qup_dma_done;
if (xfer->rx_buf) {
ret = spi_qup_prep_sg(master, xfer, DMA_DEV_TO_MEM, rx_done);
if (ret)
return ret;
dma_async_issue_pending(master->dma_rx);
}
if (xfer->tx_buf) {
ret = spi_qup_prep_sg(master, xfer, DMA_MEM_TO_DEV, tx_done);
if (ret)
return ret;
dma_async_issue_pending(master->dma_tx);
}
return 0;
}
static int spi_qup_do_pio(struct spi_master *master, struct spi_transfer *xfer)
{
struct spi_qup *qup = spi_master_get_devdata(master);
int ret;
ret = spi_qup_set_state(qup, QUP_STATE_RUN);
if (ret) {
dev_warn(qup->dev, "cannot set RUN state\n");
return ret;
}
ret = spi_qup_set_state(qup, QUP_STATE_PAUSE);
if (ret) {
dev_warn(qup->dev, "cannot set PAUSE state\n");
return ret;
}
spi_qup_fifo_write(qup, xfer);
return 0;
}
static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id)
{
struct spi_qup *controller = dev_id;
@ -315,11 +424,13 @@ static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id)
error = -EIO;
}
if (opflags & QUP_OP_IN_SERVICE_FLAG)
spi_qup_fifo_read(controller, xfer);
if (!controller->use_dma) {
if (opflags & QUP_OP_IN_SERVICE_FLAG)
spi_qup_fifo_read(controller, xfer);
if (opflags & QUP_OP_OUT_SERVICE_FLAG)
spi_qup_fifo_write(controller, xfer);
if (opflags & QUP_OP_OUT_SERVICE_FLAG)
spi_qup_fifo_write(controller, xfer);
}
spin_lock_irqsave(&controller->lock, flags);
controller->error = error;
@ -332,13 +443,35 @@ static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id)
return IRQ_HANDLED;
}
static u32
spi_qup_get_mode(struct spi_master *master, struct spi_transfer *xfer)
{
struct spi_qup *qup = spi_master_get_devdata(master);
u32 mode;
qup->w_size = 4;
if (xfer->bits_per_word <= 8)
qup->w_size = 1;
else if (xfer->bits_per_word <= 16)
qup->w_size = 2;
qup->n_words = xfer->len / qup->w_size;
if (qup->n_words <= (qup->in_fifo_sz / sizeof(u32)))
mode = QUP_IO_M_MODE_FIFO;
else
mode = QUP_IO_M_MODE_BLOCK;
return mode;
}
/* set clock freq ... bits per word */
static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)
{
struct spi_qup *controller = spi_master_get_devdata(spi->master);
u32 config, iomode, mode, control;
int ret, n_words, w_size;
int ret, n_words;
if (spi->mode & SPI_LOOP && xfer->len > controller->in_fifo_sz) {
dev_err(controller->dev, "too big size for loopback %d > %d\n",
@ -358,35 +491,54 @@ static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)
return -EIO;
}
w_size = 4;
if (xfer->bits_per_word <= 8)
w_size = 1;
else if (xfer->bits_per_word <= 16)
w_size = 2;
mode = spi_qup_get_mode(spi->master, xfer);
n_words = controller->n_words;
n_words = xfer->len / w_size;
controller->w_size = w_size;
if (n_words <= (controller->in_fifo_sz / sizeof(u32))) {
mode = QUP_IO_M_MODE_FIFO;
if (mode == QUP_IO_M_MODE_FIFO) {
writel_relaxed(n_words, controller->base + QUP_MX_READ_CNT);
writel_relaxed(n_words, controller->base + QUP_MX_WRITE_CNT);
/* must be zero for FIFO */
writel_relaxed(0, controller->base + QUP_MX_INPUT_CNT);
writel_relaxed(0, controller->base + QUP_MX_OUTPUT_CNT);
} else {
mode = QUP_IO_M_MODE_BLOCK;
} else if (!controller->use_dma) {
writel_relaxed(n_words, controller->base + QUP_MX_INPUT_CNT);
writel_relaxed(n_words, controller->base + QUP_MX_OUTPUT_CNT);
/* must be zero for BLOCK and BAM */
writel_relaxed(0, controller->base + QUP_MX_READ_CNT);
writel_relaxed(0, controller->base + QUP_MX_WRITE_CNT);
} else {
mode = QUP_IO_M_MODE_BAM;
writel_relaxed(0, controller->base + QUP_MX_READ_CNT);
writel_relaxed(0, controller->base + QUP_MX_WRITE_CNT);
if (!controller->qup_v1) {
void __iomem *input_cnt;
input_cnt = controller->base + QUP_MX_INPUT_CNT;
/*
* for DMA transfers, both QUP_MX_INPUT_CNT and
* QUP_MX_OUTPUT_CNT must be zero to all cases but one.
* That case is a non-balanced transfer when there is
* only a rx_buf.
*/
if (xfer->tx_buf)
writel_relaxed(0, input_cnt);
else
writel_relaxed(n_words, input_cnt);
writel_relaxed(0, controller->base + QUP_MX_OUTPUT_CNT);
}
}
iomode = readl_relaxed(controller->base + QUP_IO_M_MODES);
/* Set input and output transfer mode */
iomode &= ~(QUP_IO_M_INPUT_MODE_MASK | QUP_IO_M_OUTPUT_MODE_MASK);
iomode &= ~(QUP_IO_M_PACK_EN | QUP_IO_M_UNPACK_EN);
if (!controller->use_dma)
iomode &= ~(QUP_IO_M_PACK_EN | QUP_IO_M_UNPACK_EN);
else
iomode |= QUP_IO_M_PACK_EN | QUP_IO_M_UNPACK_EN;
iomode |= (mode << QUP_IO_M_OUTPUT_MODE_MASK_SHIFT);
iomode |= (mode << QUP_IO_M_INPUT_MODE_MASK_SHIFT);
@ -428,11 +580,31 @@ static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)
config &= ~(QUP_CONFIG_NO_INPUT | QUP_CONFIG_NO_OUTPUT | QUP_CONFIG_N);
config |= xfer->bits_per_word - 1;
config |= QUP_CONFIG_SPI_MODE;
if (controller->use_dma) {
if (!xfer->tx_buf)
config |= QUP_CONFIG_NO_OUTPUT;
if (!xfer->rx_buf)
config |= QUP_CONFIG_NO_INPUT;
}
writel_relaxed(config, controller->base + QUP_CONFIG);
/* only write to OPERATIONAL_MASK when register is present */
if (!controller->qup_v1)
writel_relaxed(0, controller->base + QUP_OPERATIONAL_MASK);
if (!controller->qup_v1) {
u32 mask = 0;
/*
* mask INPUT and OUTPUT service flags to prevent IRQs on FIFO
* status change in BAM mode
*/
if (mode == QUP_IO_M_MODE_BAM)
mask = QUP_OP_IN_SERVICE_FLAG | QUP_OP_OUT_SERVICE_FLAG;
writel_relaxed(mask, controller->base + QUP_OPERATIONAL_MASK);
}
return 0;
}
@ -461,17 +633,13 @@ static int spi_qup_transfer_one(struct spi_master *master,
controller->tx_bytes = 0;
spin_unlock_irqrestore(&controller->lock, flags);
if (spi_qup_set_state(controller, QUP_STATE_RUN)) {
dev_warn(controller->dev, "cannot set RUN state\n");
goto exit;
}
if (controller->use_dma)
ret = spi_qup_do_dma(master, xfer);
else
ret = spi_qup_do_pio(master, xfer);
if (spi_qup_set_state(controller, QUP_STATE_PAUSE)) {
dev_warn(controller->dev, "cannot set PAUSE state\n");
if (ret)
goto exit;
}
spi_qup_fifo_write(controller, xfer);
if (spi_qup_set_state(controller, QUP_STATE_RUN)) {
dev_warn(controller->dev, "cannot set EXECUTE state\n");
@ -480,6 +648,7 @@ static int spi_qup_transfer_one(struct spi_master *master,
if (!wait_for_completion_timeout(&controller->done, timeout))
ret = -ETIMEDOUT;
exit:
spi_qup_set_state(controller, QUP_STATE_RESET);
spin_lock_irqsave(&controller->lock, flags);
@ -487,6 +656,97 @@ static int spi_qup_transfer_one(struct spi_master *master,
if (!ret)
ret = controller->error;
spin_unlock_irqrestore(&controller->lock, flags);
if (ret && controller->use_dma)
spi_qup_dma_terminate(master, xfer);
return ret;
}
static bool spi_qup_can_dma(struct spi_master *master, struct spi_device *spi,
struct spi_transfer *xfer)
{
struct spi_qup *qup = spi_master_get_devdata(master);
size_t dma_align = dma_get_cache_alignment();
u32 mode;
qup->use_dma = 0;
if (xfer->rx_buf && (xfer->len % qup->in_blk_sz ||
IS_ERR_OR_NULL(master->dma_rx) ||
!IS_ALIGNED((size_t)xfer->rx_buf, dma_align)))
return false;
if (xfer->tx_buf && (xfer->len % qup->out_blk_sz ||
IS_ERR_OR_NULL(master->dma_tx) ||
!IS_ALIGNED((size_t)xfer->tx_buf, dma_align)))
return false;
mode = spi_qup_get_mode(master, xfer);
if (mode == QUP_IO_M_MODE_FIFO)
return false;
qup->use_dma = 1;
return true;
}
static void spi_qup_release_dma(struct spi_master *master)
{
if (!IS_ERR_OR_NULL(master->dma_rx))
dma_release_channel(master->dma_rx);
if (!IS_ERR_OR_NULL(master->dma_tx))
dma_release_channel(master->dma_tx);
}
static int spi_qup_init_dma(struct spi_master *master, resource_size_t base)
{
struct spi_qup *spi = spi_master_get_devdata(master);
struct dma_slave_config *rx_conf = &spi->rx_conf,
*tx_conf = &spi->tx_conf;
struct device *dev = spi->dev;
int ret;
/* allocate dma resources, if available */
master->dma_rx = dma_request_slave_channel_reason(dev, "rx");
if (IS_ERR(master->dma_rx))
return PTR_ERR(master->dma_rx);
master->dma_tx = dma_request_slave_channel_reason(dev, "tx");
if (IS_ERR(master->dma_tx)) {
ret = PTR_ERR(master->dma_tx);
goto err_tx;
}
/* set DMA parameters */
rx_conf->direction = DMA_DEV_TO_MEM;
rx_conf->device_fc = 1;
rx_conf->src_addr = base + QUP_INPUT_FIFO;
rx_conf->src_maxburst = spi->in_blk_sz;
tx_conf->direction = DMA_MEM_TO_DEV;
tx_conf->device_fc = 1;
tx_conf->dst_addr = base + QUP_OUTPUT_FIFO;
tx_conf->dst_maxburst = spi->out_blk_sz;
ret = dmaengine_slave_config(master->dma_rx, rx_conf);
if (ret) {
dev_err(dev, "failed to configure RX channel\n");
goto err;
}
ret = dmaengine_slave_config(master->dma_tx, tx_conf);
if (ret) {
dev_err(dev, "failed to configure TX channel\n");
goto err;
}
return 0;
err:
dma_release_channel(master->dma_tx);
err_tx:
dma_release_channel(master->dma_rx);
return ret;
}
@ -562,6 +822,8 @@ static int spi_qup_probe(struct platform_device *pdev)
master->transfer_one = spi_qup_transfer_one;
master->dev.of_node = pdev->dev.of_node;
master->auto_runtime_pm = true;
master->dma_alignment = dma_get_cache_alignment();
master->max_dma_len = SPI_MAX_DMA_XFER;
platform_set_drvdata(pdev, master);
@ -573,6 +835,12 @@ static int spi_qup_probe(struct platform_device *pdev)
controller->cclk = cclk;
controller->irq = irq;
ret = spi_qup_init_dma(master, res->start);
if (ret == -EPROBE_DEFER)
goto error;
else if (!ret)
master->can_dma = spi_qup_can_dma;
/* set v1 flag if device is version 1 */
if (of_device_is_compatible(dev->of_node, "qcom,spi-qup-v1.1.1"))
controller->qup_v1 = 1;
@ -609,7 +877,7 @@ static int spi_qup_probe(struct platform_device *pdev)
ret = spi_qup_set_state(controller, QUP_STATE_RESET);
if (ret) {
dev_err(dev, "cannot set RESET state\n");
goto error;
goto error_dma;
}
writel_relaxed(0, base + QUP_OPERATIONAL);
@ -633,7 +901,7 @@ static int spi_qup_probe(struct platform_device *pdev)
ret = devm_request_irq(dev, irq, spi_qup_qup_irq,
IRQF_TRIGGER_HIGH, pdev->name, controller);
if (ret)
goto error;
goto error_dma;
pm_runtime_set_autosuspend_delay(dev, MSEC_PER_SEC);
pm_runtime_use_autosuspend(dev);
@ -648,6 +916,8 @@ static int spi_qup_probe(struct platform_device *pdev)
disable_pm:
pm_runtime_disable(&pdev->dev);
error_dma:
spi_qup_release_dma(master);
error:
clk_disable_unprepare(cclk);
clk_disable_unprepare(iclk);
@ -739,6 +1009,8 @@ static int spi_qup_remove(struct platform_device *pdev)
if (ret)
return ret;
spi_qup_release_dma(master);
clk_disable_unprepare(controller->cclk);
clk_disable_unprepare(controller->iclk);