spi: pxa2xx: Switch to SPI core DMA mapping functionality

SPI core provides DMA mapping with scatterlists. Start using it instead
of own implementation in spi-pxa2xx. Major difference in addition to
bunch of removed boilerplate code is that SPI core does
mapping/unmapping for all transfers in a message before and after the
message sending where spi-pxa2xx did mapping/unmapping for each
transfers separately.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-pxa2xx-dma.c

@@ -20,79 +20,6 @@
 
 #include "spi-pxa2xx.h"
 
-static int pxa2xx_spi_map_dma_buffer(struct driver_data *drv_data,
-				     enum dma_data_direction dir)
-{
-	int i, nents, len = drv_data->len;
-	struct scatterlist *sg;
-	struct device *dmadev;
-	struct sg_table *sgt;
-	void *buf, *pbuf;
-
-	if (dir == DMA_TO_DEVICE) {
-		dmadev = drv_data->tx_chan->device->dev;
-		sgt = &drv_data->tx_sgt;
-		buf = drv_data->tx;
-	} else {
-		dmadev = drv_data->rx_chan->device->dev;
-		sgt = &drv_data->rx_sgt;
-		buf = drv_data->rx;
-	}
-
-	nents = DIV_ROUND_UP(len, SZ_2K);
-	if (nents != sgt->nents) {
-		int ret;
-
-		sg_free_table(sgt);
-		ret = sg_alloc_table(sgt, nents, GFP_ATOMIC);
-		if (ret)
-			return ret;
-	}
-
-	pbuf = buf;
-	for_each_sg(sgt->sgl, sg, sgt->nents, i) {
-		size_t bytes = min_t(size_t, len, SZ_2K);
-
-		sg_set_buf(sg, pbuf, bytes);
-		pbuf += bytes;
-		len -= bytes;
-	}
-
-	nents = dma_map_sg(dmadev, sgt->sgl, sgt->nents, dir);
-	if (!nents)
-		return -ENOMEM;
-
-	return nents;
-}
-
-static void pxa2xx_spi_unmap_dma_buffer(struct driver_data *drv_data,
-					enum dma_data_direction dir)
-{
-	struct device *dmadev;
-	struct sg_table *sgt;
-
-	if (dir == DMA_TO_DEVICE) {
-		dmadev = drv_data->tx_chan->device->dev;
-		sgt = &drv_data->tx_sgt;
-	} else {
-		dmadev = drv_data->rx_chan->device->dev;
-		sgt = &drv_data->rx_sgt;
-	}
-
-	dma_unmap_sg(dmadev, sgt->sgl, sgt->nents, dir);
-}
-
-static void pxa2xx_spi_unmap_dma_buffers(struct driver_data *drv_data)
-{
-	if (!drv_data->dma_mapped)
-		return;
-
-	pxa2xx_spi_unmap_dma_buffer(drv_data, DMA_FROM_DEVICE);
-	pxa2xx_spi_unmap_dma_buffer(drv_data, DMA_TO_DEVICE);
-
-	drv_data->dma_mapped = 0;
-}
-
 static void pxa2xx_spi_dma_transfer_complete(struct driver_data *drv_data,
 					     bool error)
 {
@@ -125,8 +52,6 @@ static void pxa2xx_spi_dma_transfer_complete(struct driver_data *drv_data,
 			pxa2xx_spi_write(drv_data, SSTO, 0);
 
 		if (!error) {
-			pxa2xx_spi_unmap_dma_buffers(drv_data);
-
 			msg->actual_length += drv_data->len;
 			msg->state = pxa2xx_spi_next_transfer(drv_data);
 		} else {
@@ -152,11 +77,12 @@ pxa2xx_spi_dma_prepare_one(struct driver_data *drv_data,
 			   enum dma_transfer_direction dir)
 {
 	struct chip_data *chip = drv_data->cur_chip;
+	struct spi_transfer *xfer = drv_data->cur_transfer;
 	enum dma_slave_buswidth width;
 	struct dma_slave_config cfg;
 	struct dma_chan *chan;
 	struct sg_table *sgt;
-	int nents, ret;
+	int ret;
 
 	switch (drv_data->n_bytes) {
 	case 1:
@@ -178,17 +104,15 @@ pxa2xx_spi_dma_prepare_one(struct driver_data *drv_data,
 		cfg.dst_addr_width = width;
 		cfg.dst_maxburst = chip->dma_burst_size;
 
-		sgt = &drv_data->tx_sgt;
-		nents = drv_data->tx_nents;
-		chan = drv_data->tx_chan;
+		sgt = &xfer->tx_sg;
+		chan = drv_data->master->dma_tx;
 	} else {
 		cfg.src_addr = drv_data->ssdr_physical;
 		cfg.src_addr_width = width;
 		cfg.src_maxburst = chip->dma_burst_size;
 
-		sgt = &drv_data->rx_sgt;
-		nents = drv_data->rx_nents;
-		chan = drv_data->rx_chan;
+		sgt = &xfer->rx_sg;
+		chan = drv_data->master->dma_rx;
 	}
 
 	ret = dmaengine_slave_config(chan, &cfg);
@@ -197,46 +121,10 @@ pxa2xx_spi_dma_prepare_one(struct driver_data *drv_data,
 		return NULL;
 	}
 
-	return dmaengine_prep_slave_sg(chan, sgt->sgl, nents, dir,
+	return dmaengine_prep_slave_sg(chan, sgt->sgl, sgt->nents, dir,
 				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 }
 
-bool pxa2xx_spi_dma_is_possible(size_t len)
-{
-	return len <= MAX_DMA_LEN;
-}
-
-int pxa2xx_spi_map_dma_buffers(struct driver_data *drv_data)
-{
-	const struct chip_data *chip = drv_data->cur_chip;
-	int ret;
-
-	if (!chip->enable_dma)
-		return 0;
-
-	/* Don't bother with DMA if we can't do even a single burst */
-	if (drv_data->len < chip->dma_burst_size)
-		return 0;
-
-	ret = pxa2xx_spi_map_dma_buffer(drv_data, DMA_TO_DEVICE);
-	if (ret <= 0) {
-		dev_warn(&drv_data->pdev->dev, "failed to DMA map TX\n");
-		return 0;
-	}
-
-	drv_data->tx_nents = ret;
-
-	ret = pxa2xx_spi_map_dma_buffer(drv_data, DMA_FROM_DEVICE);
-	if (ret <= 0) {
-		pxa2xx_spi_unmap_dma_buffer(drv_data, DMA_TO_DEVICE);
-		dev_warn(&drv_data->pdev->dev, "failed to DMA map RX\n");
-		return 0;
-	}
-
-	drv_data->rx_nents = ret;
-	return 1;
-}
-
 irqreturn_t pxa2xx_spi_dma_transfer(struct driver_data *drv_data)
 {
 	u32 status;
@@ -245,8 +133,8 @@ irqreturn_t pxa2xx_spi_dma_transfer(struct driver_data *drv_data)
 	if (status & SSSR_ROR) {
 		dev_err(&drv_data->pdev->dev, "FIFO overrun\n");
 
-		dmaengine_terminate_async(drv_data->rx_chan);
-		dmaengine_terminate_async(drv_data->tx_chan);
+		dmaengine_terminate_async(drv_data->master->dma_rx);
+		dmaengine_terminate_async(drv_data->master->dma_tx);
 
 		pxa2xx_spi_dma_transfer_complete(drv_data, true);
 		return IRQ_HANDLED;
@@ -285,16 +173,15 @@ int pxa2xx_spi_dma_prepare(struct driver_data *drv_data, u32 dma_burst)
 	return 0;
 
 err_rx:
-	dmaengine_terminate_async(drv_data->tx_chan);
+	dmaengine_terminate_async(drv_data->master->dma_tx);
 err_tx:
-	pxa2xx_spi_unmap_dma_buffers(drv_data);
 	return err;
 }
 
 void pxa2xx_spi_dma_start(struct driver_data *drv_data)
 {
-	dma_async_issue_pending(drv_data->rx_chan);
-	dma_async_issue_pending(drv_data->tx_chan);
+	dma_async_issue_pending(drv_data->master->dma_rx);
+	dma_async_issue_pending(drv_data->master->dma_tx);
 
 	atomic_set(&drv_data->dma_running, 1);
 }
@@ -303,21 +190,22 @@ int pxa2xx_spi_dma_setup(struct driver_data *drv_data)
 {
 	struct pxa2xx_spi_master *pdata = drv_data->master_info;
 	struct device *dev = &drv_data->pdev->dev;
+	struct spi_master *master = drv_data->master;
 	dma_cap_mask_t mask;
 
 	dma_cap_zero(mask);
 	dma_cap_set(DMA_SLAVE, mask);
 
-	drv_data->tx_chan = dma_request_slave_channel_compat(mask,
+	master->dma_tx = dma_request_slave_channel_compat(mask,
 				pdata->dma_filter, pdata->tx_param, dev, "tx");
-	if (!drv_data->tx_chan)
+	if (!master->dma_tx)
 		return -ENODEV;
 
-	drv_data->rx_chan = dma_request_slave_channel_compat(mask,
+	master->dma_rx = dma_request_slave_channel_compat(mask,
 				pdata->dma_filter, pdata->rx_param, dev, "rx");
-	if (!drv_data->rx_chan) {
-		dma_release_channel(drv_data->tx_chan);
-		drv_data->tx_chan = NULL;
+	if (!master->dma_rx) {
+		dma_release_channel(master->dma_tx);
+		master->dma_tx = NULL;
 		return -ENODEV;
 	}
 
@@ -326,17 +214,17 @@ int pxa2xx_spi_dma_setup(struct driver_data *drv_data)
 
 void pxa2xx_spi_dma_release(struct driver_data *drv_data)
 {
-	if (drv_data->rx_chan) {
-		dmaengine_terminate_sync(drv_data->rx_chan);
-		dma_release_channel(drv_data->rx_chan);
-		sg_free_table(&drv_data->rx_sgt);
-		drv_data->rx_chan = NULL;
+	struct spi_master *master = drv_data->master;
+
+	if (master->dma_rx) {
+		dmaengine_terminate_sync(master->dma_rx);
+		dma_release_channel(master->dma_rx);
+		master->dma_rx = NULL;
 	}
-	if (drv_data->tx_chan) {
-		dmaengine_terminate_sync(drv_data->tx_chan);
-		dma_release_channel(drv_data->tx_chan);
-		sg_free_table(&drv_data->tx_sgt);
-		drv_data->tx_chan = NULL;
+	if (master->dma_tx) {
+		dmaengine_terminate_sync(master->dma_tx);
+		dma_release_channel(master->dma_tx);
+		master->dma_tx = NULL;
 	}
 }
 

drivers/spi/spi-pxa2xx.c

@@ -912,6 +912,17 @@ static unsigned int pxa2xx_ssp_get_clk_div(struct driver_data *drv_data,
 	return clk_div << 8;
 }
 
+static bool pxa2xx_spi_can_dma(struct spi_master *master,
+			       struct spi_device *spi,
+			       struct spi_transfer *xfer)
+{
+	struct chip_data *chip = spi_get_ctldata(spi);
+
+	return chip->enable_dma &&
+	       xfer->len <= MAX_DMA_LEN &&
+	       xfer->len >= chip->dma_burst_size;
+}
+
 static void pump_transfers(unsigned long data)
 {
 	struct driver_data *drv_data = (struct driver_data *)data;
@@ -929,6 +940,7 @@ static void pump_transfers(unsigned long data)
 	u32 dma_burst = drv_data->cur_chip->dma_burst_size;
 	u32 change_mask = pxa2xx_spi_get_ssrc1_change_mask(drv_data);
 	int err;
+	int dma_mapped;
 
 	/* Get current state information */
 	message = drv_data->cur_msg;
@@ -963,7 +975,7 @@ static void pump_transfers(unsigned long data)
 	}
 
 	/* Check if we can DMA this transfer */
-	if (!pxa2xx_spi_dma_is_possible(transfer->len) && chip->enable_dma) {
+	if (transfer->len > MAX_DMA_LEN && chip->enable_dma) {
 
 		/* reject already-mapped transfers; PIO won't always work */
 		if (message->is_dma_mapped
@@ -1040,10 +1052,10 @@ static void pump_transfers(unsigned long data)
 
 	message->state = RUNNING_STATE;
 
-	drv_data->dma_mapped = 0;
-	if (pxa2xx_spi_dma_is_possible(drv_data->len))
-		drv_data->dma_mapped = pxa2xx_spi_map_dma_buffers(drv_data);
-	if (drv_data->dma_mapped) {
+	dma_mapped = master->can_dma &&
+		     master->can_dma(master, message->spi, transfer) &&
+		     master->cur_msg_mapped;
+	if (dma_mapped) {
 
 		/* Ensure we have the correct interrupt handler */
 		drv_data->transfer_handler = pxa2xx_spi_dma_transfer;
@@ -1075,12 +1087,12 @@ static void pump_transfers(unsigned long data)
 		dev_dbg(&message->spi->dev, "%u Hz actual, %s\n",
 			master->max_speed_hz
 				/ (1 + ((cr0 & SSCR0_SCR(0xfff)) >> 8)),
-			drv_data->dma_mapped ? "DMA" : "PIO");
+			dma_mapped ? "DMA" : "PIO");
 	else
 		dev_dbg(&message->spi->dev, "%u Hz actual, %s\n",
 			master->max_speed_hz / 2
 				/ (1 + ((cr0 & SSCR0_SCR(0x0ff)) >> 8)),
-			drv_data->dma_mapped ? "DMA" : "PIO");
+			dma_mapped ? "DMA" : "PIO");
 
 	if (is_lpss_ssp(drv_data)) {
 		if ((pxa2xx_spi_read(drv_data, SSIRF) & 0xff)
@@ -1594,6 +1606,8 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
 		if (status) {
 			dev_dbg(dev, "no DMA channels available, using PIO\n");
 			platform_info->enable_dma = false;
+		} else {
+			master->can_dma = pxa2xx_spi_can_dma;
 		}
 	}
 

drivers/spi/spi-pxa2xx.h

@@ -50,12 +50,6 @@ struct driver_data {
 	struct tasklet_struct pump_transfers;
 
 	/* DMA engine support */
-	struct dma_chan *rx_chan;
-	struct dma_chan *tx_chan;
-	struct sg_table rx_sgt;
-	struct sg_table tx_sgt;
-	int rx_nents;
-	int tx_nents;
 	atomic_t dma_running;
 
 	/* Current message transfer state info */
@@ -67,7 +61,6 @@ struct driver_data {
 	void *tx_end;
 	void *rx;
 	void *rx_end;
-	int dma_mapped;
 	u8 n_bytes;
 	int (*write)(struct driver_data *drv_data);
 	int (*read)(struct driver_data *drv_data);
@@ -145,8 +138,6 @@ extern void *pxa2xx_spi_next_transfer(struct driver_data *drv_data);
 #define MAX_DMA_LEN		SZ_64K
 #define DEFAULT_DMA_CR1		(SSCR1_TSRE | SSCR1_RSRE | SSCR1_TRAIL)
 
-extern bool pxa2xx_spi_dma_is_possible(size_t len);
-extern int pxa2xx_spi_map_dma_buffers(struct driver_data *drv_data);
 extern irqreturn_t pxa2xx_spi_dma_transfer(struct driver_data *drv_data);
 extern int pxa2xx_spi_dma_prepare(struct driver_data *drv_data, u32 dma_burst);
 extern void pxa2xx_spi_dma_start(struct driver_data *drv_data);