spi/rspi: add dmaengine support (a3633fe7) · Commits · e / devices / android_kernel_samsung_universal8890

drivers/spi/spi-rspi.c

+314 −6

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

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

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

	spsr = rspi_read8(rspi, RSPI_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)		if (spsr & SPSR_OVRF)
	rspi_write8(rspi, rspi_read8(rspi, RSPI_SPSR) & ~SPSR_OVRF,		rspi_write8(rspi, rspi_read8(rspi, RSPI_SPSR) & ~SPSR_OVRF,
	RSPI_SPCR);		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;		data = (u8 *)t->rx_buf;
	while (remain > 0) {		while (remain > 0) {
	@@ -307,6 +444,120 @@ static int rspi_receive_pio(struct rspi_data rspi, struct spi_message mesg,
	return 0;		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)		static void rspi_work(struct work_struct *work)
	{		{
	struct rspi_data *rspi = container_of(work, struct rspi_data, ws);		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) {		list_for_each_entry(t, &mesg->transfers, transfer_list) {
	if (t->tx_buf) {		if (t->tx_buf) {
			if (rspi_is_dma(rspi, t))
			ret = rspi_send_dma(rspi, t);
			else
	ret = rspi_send_pio(rspi, mesg, t);		ret = rspi_send_pio(rspi, mesg, t);
	if (ret < 0)		if (ret < 0)
	goto error;		goto error;
	}		}
	if (t->rx_buf) {		if (t->rx_buf) {
			if (rspi_is_dma(rspi, t))
			ret = rspi_receive_dma(rspi, t);
			else
	ret = rspi_receive_pio(rspi, mesg, t);		ret = rspi_receive_pio(rspi, mesg, t);
	if (ret < 0)		if (ret < 0)
	goto error;		goto error;
	@@ -406,11 +663,58 @@ static irqreturn_t rspi_irq(int irq, void *_sr)
	return ret;		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)		static int __devexit rspi_remove(struct platform_device *pdev)
	{		{
	struct rspi_data *rspi = dev_get_drvdata(&pdev->dev);		struct rspi_data *rspi = dev_get_drvdata(&pdev->dev);

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

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

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

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

include/linux/spi/rspi.h

0 → 100644

+31 −0

Original line number	Original line	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