spi/rspi: add dmaengine support (a3633fe7) · Commits · 戴 / test

drivers/spi/spi-rspi.c

+314 −6

Original line number	Diff line number	Diff line
		@@ -31,7 +31,11 @@
		#include <linux/platform_device.h>
		#include <linux/io.h>
		#include <linux/clk.h>
		#include <linux/dmaengine.h>
		#include <linux/dma-mapping.h>
		#include <linux/sh_dma.h>
		#include <linux/spi/spi.h>
		#include <linux/spi/rspi.h>

		#define RSPI_SPCR 0x00
		#define RSPI_SSLP 0x01
		@@ -141,6 +145,16 @@ struct rspi_data {
		spinlock_t lock;
		struct clk *clk;
		unsigned char spsr;

		/* for dmaengine */
		struct sh_dmae_slave dma_tx;
		struct sh_dmae_slave dma_rx;
		struct dma_chan *chan_tx;
		struct dma_chan *chan_rx;
		int irq;

		unsigned dma_width_16bit:1;
		unsigned dma_callbacked:1;
		};

		static void rspi_write8(struct rspi_data *rspi, u8 data, u16 offset)
		@@ -265,11 +279,125 @@ static int rspi_send_pio(struct rspi_data rspi, struct spi_message mesg,
		return 0;
		}

		static int rspi_receive_pio(struct rspi_data rspi, struct spi_message mesg,
		struct spi_transfer *t)
		static void rspi_dma_complete(void *arg)
		{
		struct rspi_data *rspi = arg;

		rspi->dma_callbacked = 1;
		wake_up_interruptible(&rspi->wait);
		}

		static int rspi_dma_map_sg(struct scatterlist sg, void buf, unsigned len,
		struct dma_chan *chan,
		enum dma_transfer_direction dir)
		{
		sg_init_table(sg, 1);
		sg_set_buf(sg, buf, len);
		sg_dma_len(sg) = len;
		return dma_map_sg(chan->device->dev, sg, 1, dir);
		}

		static void rspi_dma_unmap_sg(struct scatterlist sg, struct dma_chan chan,
		enum dma_transfer_direction dir)
		{
		dma_unmap_sg(chan->device->dev, sg, 1, dir);
		}

		static void rspi_memory_to_8bit(void buf, const void data, unsigned len)
		{
		u16 *dst = buf;
		const u8 *src = data;

		while (len) {
		dst++ = (u16)(src++);
		len--;
		}
		}

		static void rspi_memory_from_8bit(void buf, const void data, unsigned len)
		{
		u8 *dst = buf;
		const u16 *src = data;

		while (len) {
		dst++ = (u8)src++;
		len--;
		}
		}

		static int rspi_send_dma(struct rspi_data rspi, struct spi_transfer t)
		{
		struct scatterlist sg;
		void *buf = NULL;
		struct dma_async_tx_descriptor *desc;
		unsigned len;
		int ret = 0;

		if (rspi->dma_width_16bit) {
		/*
		* If DMAC bus width is 16-bit, the driver allocates a dummy
		* buffer. And, the driver converts original data into the
		* DMAC data as the following format:
		* original data: 1st byte, 2nd byte ...
		* DMAC data: 1st byte, dummy, 2nd byte, dummy ...
		*/
		len = t->len * 2;
		buf = kmalloc(len, GFP_KERNEL);
		if (!buf)
		return -ENOMEM;
		rspi_memory_to_8bit(buf, t->tx_buf, t->len);
		} else {
		len = t->len;
		buf = (void *)t->tx_buf;
		}

		if (!rspi_dma_map_sg(&sg, buf, len, rspi->chan_tx, DMA_TO_DEVICE)) {
		ret = -EFAULT;
		goto end_nomap;
		}
		desc = dmaengine_prep_slave_sg(rspi->chan_tx, &sg, 1, DMA_TO_DEVICE,
		DMA_PREP_INTERRUPT \| DMA_CTRL_ACK);
		if (!desc) {
		ret = -EIO;
		goto end;
		}

		/*
		* DMAC needs SPTIE, but if SPTIE is set, this IRQ routine will be
		* called. So, this driver disables the IRQ while DMA transfer.
		*/
		disable_irq(rspi->irq);

		rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) \| SPCR_TXMD, RSPI_SPCR);
		rspi_enable_irq(rspi, SPCR_SPTIE);
		rspi->dma_callbacked = 0;

		desc->callback = rspi_dma_complete;
		desc->callback_param = rspi;
		dmaengine_submit(desc);
		dma_async_issue_pending(rspi->chan_tx);

		ret = wait_event_interruptible_timeout(rspi->wait,
		rspi->dma_callbacked, HZ);
		if (ret > 0 && rspi->dma_callbacked)
		ret = 0;
		else if (!ret)
		ret = -ETIMEDOUT;
		rspi_disable_irq(rspi, SPCR_SPTIE);

		enable_irq(rspi->irq);

		end:
		rspi_dma_unmap_sg(&sg, rspi->chan_tx, DMA_TO_DEVICE);
		end_nomap:
		if (rspi->dma_width_16bit)
		kfree(buf);

		return ret;
		}

		static void rspi_receive_init(struct rspi_data *rspi)
		{
		int remain = t->len;
		u8 *data;
		unsigned char spsr;

		spsr = rspi_read8(rspi, RSPI_SPSR);
		@@ -278,6 +406,15 @@ static int rspi_receive_pio(struct rspi_data rspi, struct spi_message mesg,
		if (spsr & SPSR_OVRF)
		rspi_write8(rspi, rspi_read8(rspi, RSPI_SPSR) & ~SPSR_OVRF,
		RSPI_SPCR);
		}

		static int rspi_receive_pio(struct rspi_data rspi, struct spi_message mesg,
		struct spi_transfer *t)
		{
		int remain = t->len;
		u8 *data;

		rspi_receive_init(rspi);

		data = (u8 *)t->rx_buf;
		while (remain > 0) {
		@@ -307,6 +444,120 @@ static int rspi_receive_pio(struct rspi_data rspi, struct spi_message mesg,
		return 0;
		}

		static int rspi_receive_dma(struct rspi_data rspi, struct spi_transfer t)
		{
		struct scatterlist sg, sg_dummy;
		void dummy = NULL, rx_buf = NULL;
		struct dma_async_tx_descriptor desc, desc_dummy;
		unsigned len;
		int ret = 0;

		if (rspi->dma_width_16bit) {
		/*
		* If DMAC bus width is 16-bit, the driver allocates a dummy
		* buffer. And, finally the driver converts the DMAC data into
		* actual data as the following format:
		* DMAC data: 1st byte, dummy, 2nd byte, dummy ...
		* actual data: 1st byte, 2nd byte ...
		*/
		len = t->len * 2;
		rx_buf = kmalloc(len, GFP_KERNEL);
		if (!rx_buf)
		return -ENOMEM;
		} else {
		len = t->len;
		rx_buf = t->rx_buf;
		}

		/* prepare dummy transfer to generate SPI clocks */
		dummy = kzalloc(len, GFP_KERNEL);
		if (!dummy) {
		ret = -ENOMEM;
		goto end_nomap;
		}
		if (!rspi_dma_map_sg(&sg_dummy, dummy, len, rspi->chan_tx,
		DMA_TO_DEVICE)) {
		ret = -EFAULT;
		goto end_nomap;
		}
		desc_dummy = dmaengine_prep_slave_sg(rspi->chan_tx, &sg_dummy, 1,
		DMA_TO_DEVICE, DMA_PREP_INTERRUPT \| DMA_CTRL_ACK);
		if (!desc_dummy) {
		ret = -EIO;
		goto end_dummy_mapped;
		}

		/* prepare receive transfer */
		if (!rspi_dma_map_sg(&sg, rx_buf, len, rspi->chan_rx,
		DMA_FROM_DEVICE)) {
		ret = -EFAULT;
		goto end_dummy_mapped;

		}
		desc = dmaengine_prep_slave_sg(rspi->chan_rx, &sg, 1, DMA_FROM_DEVICE,
		DMA_PREP_INTERRUPT \| DMA_CTRL_ACK);
		if (!desc) {
		ret = -EIO;
		goto end;
		}

		rspi_receive_init(rspi);

		/*
		* DMAC needs SPTIE, but if SPTIE is set, this IRQ routine will be
		* called. So, this driver disables the IRQ while DMA transfer.
		*/
		disable_irq(rspi->irq);

		rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) & ~SPCR_TXMD, RSPI_SPCR);
		rspi_enable_irq(rspi, SPCR_SPTIE \| SPCR_SPRIE);
		rspi->dma_callbacked = 0;

		desc->callback = rspi_dma_complete;
		desc->callback_param = rspi;
		dmaengine_submit(desc);
		dma_async_issue_pending(rspi->chan_rx);

		desc_dummy->callback = NULL; /* No callback */
		dmaengine_submit(desc_dummy);
		dma_async_issue_pending(rspi->chan_tx);

		ret = wait_event_interruptible_timeout(rspi->wait,
		rspi->dma_callbacked, HZ);
		if (ret > 0 && rspi->dma_callbacked)
		ret = 0;
		else if (!ret)
		ret = -ETIMEDOUT;
		rspi_disable_irq(rspi, SPCR_SPTIE \| SPCR_SPRIE);

		enable_irq(rspi->irq);

		end:
		rspi_dma_unmap_sg(&sg, rspi->chan_rx, DMA_FROM_DEVICE);
		end_dummy_mapped:
		rspi_dma_unmap_sg(&sg_dummy, rspi->chan_tx, DMA_TO_DEVICE);
		end_nomap:
		if (rspi->dma_width_16bit) {
		if (!ret)
		rspi_memory_from_8bit(t->rx_buf, rx_buf, t->len);
		kfree(rx_buf);
		}
		kfree(dummy);

		return ret;
		}

		static int rspi_is_dma(struct rspi_data rspi, struct spi_transfer t)
		{
		if (t->tx_buf && rspi->chan_tx)
		return 1;
		/* If the module receives data by DMAC, it also needs TX DMAC */
		if (t->rx_buf && rspi->chan_tx && rspi->chan_rx)
		return 1;

		return 0;
		}

		static void rspi_work(struct work_struct *work)
		{
		struct rspi_data *rspi = container_of(work, struct rspi_data, ws);
		@@ -325,11 +576,17 @@ static void rspi_work(struct work_struct *work)

		list_for_each_entry(t, &mesg->transfers, transfer_list) {
		if (t->tx_buf) {
		if (rspi_is_dma(rspi, t))
		ret = rspi_send_dma(rspi, t);
		else
		ret = rspi_send_pio(rspi, mesg, t);
		if (ret < 0)
		goto error;
		}
		if (t->rx_buf) {
		if (rspi_is_dma(rspi, t))
		ret = rspi_receive_dma(rspi, t);
		else
		ret = rspi_receive_pio(rspi, mesg, t);
		if (ret < 0)
		goto error;
		@@ -406,11 +663,58 @@ static irqreturn_t rspi_irq(int irq, void *_sr)
		return ret;
		}

		static bool rspi_filter(struct dma_chan chan, void filter_param)
		{
		chan->private = filter_param;
		return true;
		}

		static void __devinit rspi_request_dma(struct rspi_data *rspi,
		struct platform_device *pdev)
		{
		struct rspi_plat_data *rspi_pd = pdev->dev.platform_data;
		dma_cap_mask_t mask;

		if (!rspi_pd)
		return;

		rspi->dma_width_16bit = rspi_pd->dma_width_16bit;

		/* If the module receives data by DMAC, it also needs TX DMAC */
		if (rspi_pd->dma_rx_id && rspi_pd->dma_tx_id) {
		dma_cap_zero(mask);
		dma_cap_set(DMA_SLAVE, mask);
		rspi->dma_rx.slave_id = rspi_pd->dma_rx_id;
		rspi->chan_rx = dma_request_channel(mask, rspi_filter,
		&rspi->dma_rx);
		if (rspi->chan_rx)
		dev_info(&pdev->dev, "Use DMA when rx.\n");
		}
		if (rspi_pd->dma_tx_id) {
		dma_cap_zero(mask);
		dma_cap_set(DMA_SLAVE, mask);
		rspi->dma_tx.slave_id = rspi_pd->dma_tx_id;
		rspi->chan_tx = dma_request_channel(mask, rspi_filter,
		&rspi->dma_tx);
		if (rspi->chan_tx)
		dev_info(&pdev->dev, "Use DMA when tx\n");
		}
		}

		static void __devexit rspi_release_dma(struct rspi_data *rspi)
		{
		if (rspi->chan_tx)
		dma_release_channel(rspi->chan_tx);
		if (rspi->chan_rx)
		dma_release_channel(rspi->chan_rx);
		}

		static int __devexit rspi_remove(struct platform_device *pdev)
		{
		struct rspi_data *rspi = dev_get_drvdata(&pdev->dev);

		spi_unregister_master(rspi->master);
		rspi_release_dma(rspi);
		free_irq(platform_get_irq(pdev, 0), rspi);
		clk_put(rspi->clk);
		iounmap(rspi->addr);
		@@ -483,6 +787,9 @@ static int __devinit rspi_probe(struct platform_device *pdev)
		goto error3;
		}

		rspi->irq = irq;
		rspi_request_dma(rspi, pdev);

		ret = spi_register_master(master);
		if (ret < 0) {
		dev_err(&pdev->dev, "spi_register_master error.\n");
		@@ -494,6 +801,7 @@ static int __devinit rspi_probe(struct platform_device *pdev)
		return 0;

		error4:
		rspi_release_dma(rspi);
		free_irq(irq, rspi);
		error3:
		clk_put(rspi->clk);

include/linux/spi/rspi.h

0 → 100644

+31 −0

Original line number	Diff line number	Diff line
		/*
		* Renesas SPI driver
		*
		* Copyright (C) 2012 Renesas Solutions Corp.
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; version 2 of the License.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to the Free Software
		* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
		*
		*/

		#ifndef __LINUX_SPI_RENESAS_SPI_H__
		#define __LINUX_SPI_RENESAS_SPI_H__

		struct rspi_plat_data {
		unsigned int dma_tx_id;
		unsigned int dma_rx_id;

		unsigned dma_width_16bit:1; /* DMAC read/write width = 16-bit */
		};

		#endif

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