[PATCH] spi: qup: Add DMA capabilities
From: Andy Gross
Date: Thu Jun 26 2014 - 17:07:16 EST
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@xxxxxxxxxxxxxx>
---
.../devicetree/bindings/spi/qcom,spi-qup.txt | 10 +
drivers/spi/spi-qup.c | 361 ++++++++++++++++++--
2 files changed, 350 insertions(+), 21 deletions(-)
diff --git a/Documentation/devicetree/bindings/spi/qcom,spi-qup.txt b/Documentation/devicetree/bindings/spi/qcom,spi-qup.txt
index b82a268..4d8977a 100644
--- a/Documentation/devicetree/bindings/spi/qcom,spi-qup.txt
+++ b/Documentation/devicetree/bindings/spi/qcom,spi-qup.txt
@@ -23,6 +23,12 @@ Optional properties:
- spi-max-frequency: Specifies maximum SPI clock frequency,
Units - Hz. Definition as per
Documentation/devicetree/bindings/spi/spi-bus.txt
+- 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
@@ -41,6 +47,10 @@ Example:
clocks = <&gcc GCC_BLSP2_QUP2_SPI_APPS_CLK>, <&gcc GCC_BLSP2_AHB_CLK>;
clock-names = "core", "iface";
+ dmas = <&blsp2_bam 2>,
+ <&blsp2_bam 3>;
+ dma-names = "rx", "tx";
+
pinctrl-names = "default";
pinctrl-0 = <&spi8_default>;
diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index fc1de86..9b01db5 100644
--- a/drivers/spi/spi-qup.c
+++ b/drivers/spi/spi-qup.c
@@ -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_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
@@ -142,6 +146,17 @@ struct spi_qup {
int w_size; /* bytes per SPI word */
int tx_bytes;
int rx_bytes;
+
+ int use_dma;
+
+ struct dma_chan *rx_chan;
+ struct dma_slave_config rx_conf;
+ struct dma_chan *tx_chan;
+ struct dma_slave_config tx_conf;
+ dma_addr_t rx_dma;
+ dma_addr_t tx_dma;
+ void *dummy;
+ atomic_t dma_outstanding;
};
@@ -265,6 +280,221 @@ static void spi_qup_fifo_write(struct spi_qup *controller,
}
}
+static void qup_dma_callback(void *data)
+{
+ struct spi_qup *controller = data;
+
+ if (atomic_dec_and_test(&controller->dma_outstanding))
+ complete(&controller->done);
+}
+
+static int spi_qup_do_dma(struct spi_qup *controller, struct spi_transfer *xfer)
+{
+ struct dma_async_tx_descriptor *rxd, *txd;
+ dma_cookie_t rx_cookie, tx_cookie;
+ u32 xfer_len, rx_align = 0, tx_align = 0, n_words;
+ struct scatterlist tx_sg[2], rx_sg[2];
+ int ret = 0;
+ u32 bytes_to_xfer = xfer->len;
+ u32 offset = 0;
+ u32 rx_nents = 0, tx_nents = 0;
+ dma_addr_t rx_dma = 0, tx_dma = 0, rx_dummy_dma = 0, tx_dummy_dma = 0;
+
+
+ if (xfer->rx_buf) {
+ rx_dma = dma_map_single(controller->dev, xfer->rx_buf,
+ xfer->len, DMA_FROM_DEVICE);
+
+ if (dma_mapping_error(controller->dev, rx_dma)) {
+ ret = -ENOMEM;
+ return ret;
+ }
+
+ /* check to see if we need dummy buffer for leftover bytes */
+ rx_align = xfer->len % controller->in_blk_sz;
+ if (rx_align) {
+ rx_dummy_dma = dma_map_single(controller->dev,
+ controller->dummy, controller->in_fifo_sz,
+ DMA_FROM_DEVICE);
+
+ if (dma_mapping_error(controller->dev, rx_dummy_dma)) {
+ ret = -ENOMEM;
+ goto err_map_rx_dummy;
+ }
+ }
+ }
+
+ if (xfer->tx_buf) {
+ tx_dma = dma_map_single(controller->dev,
+ (void *)xfer->tx_buf, xfer->len, DMA_TO_DEVICE);
+
+ if (dma_mapping_error(controller->dev, tx_dma)) {
+ ret = -ENOMEM;
+ goto err_map_tx;
+ }
+
+ /* check to see if we need dummy buffer for leftover bytes */
+ tx_align = xfer->len % controller->out_blk_sz;
+ if (tx_align) {
+ memcpy(controller->dummy + SZ_1K,
+ xfer->tx_buf + xfer->len - tx_align,
+ tx_align);
+ memset(controller->dummy + SZ_1K + tx_align, 0,
+ controller->out_blk_sz - tx_align);
+
+ tx_dummy_dma = dma_map_single(controller->dev,
+ controller->dummy + SZ_1K,
+ controller->out_blk_sz, DMA_TO_DEVICE);
+
+ if (dma_mapping_error(controller->dev, tx_dummy_dma)) {
+ ret = -ENOMEM;
+ goto err_map_tx_dummy;
+ }
+ }
+ }
+
+ atomic_set(&controller->dma_outstanding, 0);
+
+ while (bytes_to_xfer > 0) {
+ xfer_len = min_t(u32, bytes_to_xfer, SPI_MAX_XFER);
+ n_words = DIV_ROUND_UP(xfer_len, controller->w_size);
+
+ /* write out current word count to controller */
+ writel_relaxed(n_words, controller->base + QUP_MX_INPUT_CNT);
+ writel_relaxed(n_words, controller->base + QUP_MX_OUTPUT_CNT);
+
+ reinit_completion(&controller->done);
+
+ if (xfer->tx_buf) {
+ /* recalc align for each transaction */
+ tx_align = xfer_len % controller->out_blk_sz;
+
+ if (tx_align)
+ tx_nents = 2;
+ else
+ tx_nents = 1;
+
+ /* initialize scatterlists */
+ sg_init_table(tx_sg, tx_nents);
+ sg_dma_len(&tx_sg[0]) = xfer_len - tx_align;
+ sg_dma_address(&tx_sg[0]) = tx_dma + offset;
+
+ /* account for non block size transfer */
+ if (tx_align) {
+ sg_dma_len(&tx_sg[1]) = controller->out_blk_sz;
+ sg_dma_address(&tx_sg[1]) = tx_dummy_dma;
+ }
+
+ txd = dmaengine_prep_slave_sg(controller->tx_chan,
+ tx_sg, tx_nents, DMA_MEM_TO_DEV, 0);
+ if (!txd) {
+ ret = -ENOMEM;
+ goto err_unmap;
+ }
+
+ atomic_inc(&controller->dma_outstanding);
+
+ txd->callback = qup_dma_callback;
+ txd->callback_param = controller;
+
+ tx_cookie = dmaengine_submit(txd);
+
+ dma_async_issue_pending(controller->tx_chan);
+ }
+
+ if (xfer->rx_buf) {
+ /* recalc align for each transaction */
+ rx_align = xfer_len % controller->in_blk_sz;
+
+ if (rx_align)
+ rx_nents = 2;
+ else
+ rx_nents = 1;
+
+ /* initialize scatterlists */
+ sg_init_table(rx_sg, rx_nents);
+ sg_dma_address(&rx_sg[0]) = rx_dma + offset;
+ sg_dma_len(&rx_sg[0]) = xfer_len - rx_align;
+
+ /* account for non block size transfer */
+ if (rx_align) {
+ sg_dma_len(&rx_sg[1]) = controller->in_blk_sz;
+ sg_dma_address(&rx_sg[1]) = rx_dummy_dma;
+ }
+
+ rxd = dmaengine_prep_slave_sg(controller->rx_chan,
+ rx_sg, rx_nents, DMA_DEV_TO_MEM, 0);
+ if (!rxd) {
+ ret = -ENOMEM;
+ goto err_unmap;
+ }
+
+ atomic_inc(&controller->dma_outstanding);
+
+ rxd->callback = qup_dma_callback;
+ rxd->callback_param = controller;
+
+ rx_cookie = dmaengine_submit(rxd);
+
+ dma_async_issue_pending(controller->rx_chan);
+ }
+
+ if (spi_qup_set_state(controller, QUP_STATE_RUN)) {
+ dev_warn(controller->dev, "cannot set EXECUTE state\n");
+ goto err_unmap;
+ }
+
+ if (!wait_for_completion_timeout(&controller->done,
+ msecs_to_jiffies(1000))) {
+ ret = -ETIMEDOUT;
+
+ /* clear out all the DMA transactions */
+ if (xfer->tx_buf)
+ dmaengine_terminate_all(controller->tx_chan);
+ if (xfer->rx_buf)
+ dmaengine_terminate_all(controller->rx_chan);
+
+ goto err_unmap;
+ }
+
+ if (rx_align)
+ memcpy(xfer->rx_buf + offset + xfer->len - rx_align,
+ controller->dummy, rx_align);
+
+ /* adjust remaining bytes to transfer */
+ bytes_to_xfer -= xfer_len;
+ offset += xfer_len;
+
+
+ /* reset mini-core state so we can program next transaction */
+ if (spi_qup_set_state(controller, QUP_STATE_RESET)) {
+ dev_err(controller->dev, "cannot set RESET state\n");
+ goto err_unmap;
+ }
+ }
+
+ ret = 0;
+
+err_unmap:
+ if (tx_align)
+ dma_unmap_single(controller->dev, tx_dummy_dma,
+ controller->out_fifo_sz, DMA_TO_DEVICE);
+err_map_tx_dummy:
+ if (xfer->tx_buf)
+ dma_unmap_single(controller->dev, tx_dma, xfer->len,
+ DMA_TO_DEVICE);
+err_map_tx:
+ if (rx_align)
+ dma_unmap_single(controller->dev, rx_dummy_dma,
+ controller->in_fifo_sz, DMA_FROM_DEVICE);
+err_map_rx_dummy:
+ if (xfer->rx_buf)
+ dma_unmap_single(controller->dev, rx_dma, xfer->len,
+ DMA_FROM_DEVICE);
+
+ return ret;
+}
+
static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id)
{
struct spi_qup *controller = dev_id;
@@ -314,11 +544,13 @@ 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;
@@ -338,6 +570,8 @@ 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;
int ret, n_words, w_size;
+ size_t dma_align = dma_get_cache_alignment();
+ u32 dma_available = 0;
if (spi->mode & SPI_LOOP && xfer->len > controller->in_fifo_sz) {
dev_err(controller->dev, "too big size for loopback %d > %d\n",
@@ -366,6 +600,11 @@ static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)
n_words = xfer->len / w_size;
controller->w_size = w_size;
+ if (controller->rx_chan &&
+ IS_ALIGNED((size_t)xfer->tx_buf, dma_align) &&
+ IS_ALIGNED((size_t)xfer->rx_buf, dma_align))
+ dma_available = 1;
+
if (n_words <= (controller->in_fifo_sz / sizeof(u32))) {
mode = QUP_IO_M_MODE_FIFO;
writel_relaxed(n_words, controller->base + QUP_MX_READ_CNT);
@@ -373,19 +612,31 @@ static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)
/* must be zero for FIFO */
writel_relaxed(0, controller->base + QUP_MX_INPUT_CNT);
writel_relaxed(0, controller->base + QUP_MX_OUTPUT_CNT);
- } else {
+ controller->use_dma = 0;
+ } else if (!dma_available) {
mode = QUP_IO_M_MODE_BLOCK;
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);
+ controller->use_dma = 0;
+ } else {
+ mode = QUP_IO_M_MODE_DMOV;
+ writel_relaxed(0, controller->base + QUP_MX_READ_CNT);
+ writel_relaxed(0, controller->base + QUP_MX_WRITE_CNT);
+ controller->use_dma = 1;
}
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);
@@ -418,6 +669,14 @@ 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);
writel_relaxed(0, controller->base + QUP_OPERATIONAL_MASK);
@@ -474,25 +733,29 @@ 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(controller, xfer);
+ } else {
+ if (spi_qup_set_state(controller, QUP_STATE_RUN)) {
+ dev_warn(controller->dev, "cannot set RUN state\n");
+ goto exit;
+ }
- if (spi_qup_set_state(controller, QUP_STATE_PAUSE)) {
- dev_warn(controller->dev, "cannot set PAUSE state\n");
- goto exit;
- }
+ if (spi_qup_set_state(controller, QUP_STATE_PAUSE)) {
+ dev_warn(controller->dev, "cannot set PAUSE state\n");
+ goto exit;
+ }
- spi_qup_fifo_write(controller, xfer);
+ spi_qup_fifo_write(controller, xfer);
- if (spi_qup_set_state(controller, QUP_STATE_RUN)) {
- dev_warn(controller->dev, "cannot set EXECUTE state\n");
- goto exit;
- }
+ if (spi_qup_set_state(controller, QUP_STATE_RUN)) {
+ dev_warn(controller->dev, "cannot set EXECUTE state\n");
+ goto exit;
+ }
- if (!wait_for_completion_timeout(&controller->done, timeout))
- ret = -ETIMEDOUT;
+ 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);
@@ -580,6 +843,7 @@ 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();
platform_set_drvdata(pdev, master);
@@ -632,6 +896,56 @@ static int spi_qup_probe(struct platform_device *pdev)
writel_relaxed(SPI_ERROR_CLK_UNDER_RUN | SPI_ERROR_CLK_OVER_RUN,
base + SPI_ERROR_FLAGS_EN);
+ /* allocate dma resources, if available */
+ controller->rx_chan = dma_request_slave_channel(&pdev->dev, "rx");
+ if (controller->rx_chan) {
+ controller->tx_chan =
+ dma_request_slave_channel(&pdev->dev, "tx");
+
+ if (!controller->tx_chan) {
+ dev_err(&pdev->dev, "Failed to allocate dma tx chan");
+ dma_release_channel(controller->rx_chan);
+ }
+
+ /* set DMA parameters */
+ controller->rx_conf.device_fc = 1;
+ controller->rx_conf.src_addr = res->start + QUP_INPUT_FIFO;
+ controller->rx_conf.src_maxburst = controller->in_blk_sz;
+
+ controller->tx_conf.device_fc = 1;
+ controller->tx_conf.dst_addr = res->start + QUP_OUTPUT_FIFO;
+ controller->tx_conf.dst_maxburst = controller->out_blk_sz;
+
+ if (dmaengine_slave_config(controller->rx_chan,
+ &controller->rx_conf)) {
+ dev_err(&pdev->dev, "failed to configure RX channel\n");
+
+ dma_release_channel(controller->rx_chan);
+ dma_release_channel(controller->tx_chan);
+ controller->tx_chan = NULL;
+ controller->rx_chan = NULL;
+ } else if (dmaengine_slave_config(controller->tx_chan,
+ &controller->tx_conf)) {
+ dev_err(&pdev->dev, "failed to configure TX channel\n");
+
+ dma_release_channel(controller->rx_chan);
+ dma_release_channel(controller->tx_chan);
+ controller->tx_chan = NULL;
+ controller->rx_chan = NULL;
+ }
+
+ controller->dummy = devm_kmalloc(controller->dev, PAGE_SIZE,
+ GFP_KERNEL);
+
+ if (!controller->dummy) {
+ dma_release_channel(controller->rx_chan);
+ dma_release_channel(controller->tx_chan);
+ controller->tx_chan = NULL;
+ controller->rx_chan = NULL;
+ }
+ }
+
+
writel_relaxed(0, base + SPI_CONFIG);
writel_relaxed(SPI_IO_C_NO_TRI_STATE, base + SPI_IO_CONTROL);
@@ -741,6 +1055,11 @@ static int spi_qup_remove(struct platform_device *pdev)
if (ret)
return ret;
+ if (controller->rx_chan)
+ dma_release_channel(controller->rx_chan);
+ if (controller->tx_chan)
+ dma_release_channel(controller->tx_chan);
+
clk_disable_unprepare(controller->cclk);
clk_disable_unprepare(controller->iclk);
--
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