[linux-2.6-block.git] / drivers / spi / spi-pxa2xx-dma.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * PXA2xx SPI DMA engine support.
 *
 * Copyright (C) 2013, 2021 Intel Corporation
 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
 */

#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/scatterlist.h>
#include <linux/sizes.h>

#include <linux/spi/pxa2xx_spi.h>
#include <linux/spi/spi.h>

#include "spi-pxa2xx.h"

static void pxa2xx_spi_dma_transfer_complete(struct driver_data *drv_data,
					     bool error)
{
	struct spi_message *msg = drv_data->controller->cur_msg;

	/*
	 * It is possible that one CPU is handling ROR interrupt and other
	 * just gets DMA completion. Calling pump_transfers() twice for the
	 * same transfer leads to problems thus we prevent concurrent calls
	 * by using dma_running.
	 */
	if (atomic_dec_and_test(&drv_data->dma_running)) {
		/*
		 * If the other CPU is still handling the ROR interrupt we
		 * might not know about the error yet. So we re-check the
		 * ROR bit here before we clear the status register.
		 */
		if (!error)
			error = read_SSSR_bits(drv_data, drv_data->mask_sr) & SSSR_ROR;

		/* Clear status & disable interrupts */
		clear_SSCR1_bits(drv_data, drv_data->dma_cr1);
		write_SSSR_CS(drv_data, drv_data->clear_sr);
		if (!pxa25x_ssp_comp(drv_data))
			pxa2xx_spi_write(drv_data, SSTO, 0);

		if (error) {
			/* In case we got an error we disable the SSP now */
			pxa_ssp_disable(drv_data->ssp);
			msg->status = -EIO;
		}

		spi_finalize_current_transfer(drv_data->controller);
	}
}

static void pxa2xx_spi_dma_callback(void *data)
{
	pxa2xx_spi_dma_transfer_complete(data, false);
}

static struct dma_async_tx_descriptor *
pxa2xx_spi_dma_prepare_one(struct driver_data *drv_data,
			   enum dma_transfer_direction dir,
			   struct spi_transfer *xfer)
{
	struct chip_data *chip =
		spi_get_ctldata(drv_data->controller->cur_msg->spi);
	enum dma_slave_buswidth width;
	struct dma_slave_config cfg;
	struct dma_chan *chan;
	struct sg_table *sgt;
	int ret;

	switch (drv_data->n_bytes) {
	case 1:
		width = DMA_SLAVE_BUSWIDTH_1_BYTE;
		break;
	case 2:
		width = DMA_SLAVE_BUSWIDTH_2_BYTES;
		break;
	default:
		width = DMA_SLAVE_BUSWIDTH_4_BYTES;
		break;
	}

	memset(&cfg, 0, sizeof(cfg));
	cfg.direction = dir;

	if (dir == DMA_MEM_TO_DEV) {
		cfg.dst_addr = drv_data->ssp->phys_base + SSDR;
		cfg.dst_addr_width = width;
		cfg.dst_maxburst = chip->dma_burst_size;

		sgt = &xfer->tx_sg;
		chan = drv_data->controller->dma_tx;
	} else {
		cfg.src_addr = drv_data->ssp->phys_base + SSDR;
		cfg.src_addr_width = width;
		cfg.src_maxburst = chip->dma_burst_size;

		sgt = &xfer->rx_sg;
		chan = drv_data->controller->dma_rx;
	}

	ret = dmaengine_slave_config(chan, &cfg);
	if (ret) {
		dev_warn(drv_data->ssp->dev, "DMA slave config failed\n");
		return NULL;
	}

	return dmaengine_prep_slave_sg(chan, sgt->sgl, sgt->nents, dir,
				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
}

irqreturn_t pxa2xx_spi_dma_transfer(struct driver_data *drv_data)
{
	u32 status;

	status = read_SSSR_bits(drv_data, drv_data->mask_sr);
	if (status & SSSR_ROR) {
		dev_err(drv_data->ssp->dev, "FIFO overrun\n");

		dmaengine_terminate_async(drv_data->controller->dma_rx);
		dmaengine_terminate_async(drv_data->controller->dma_tx);

		pxa2xx_spi_dma_transfer_complete(drv_data, true);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

int pxa2xx_spi_dma_prepare(struct driver_data *drv_data,
			   struct spi_transfer *xfer)
{
	struct dma_async_tx_descriptor *tx_desc, *rx_desc;
	int err;

	tx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_MEM_TO_DEV, xfer);
	if (!tx_desc) {
		dev_err(drv_data->ssp->dev, "failed to get DMA TX descriptor\n");
		err = -EBUSY;
		goto err_tx;
	}

	rx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_DEV_TO_MEM, xfer);
	if (!rx_desc) {
		dev_err(drv_data->ssp->dev, "failed to get DMA RX descriptor\n");
		err = -EBUSY;
		goto err_rx;
	}

	/* We are ready when RX completes */
	rx_desc->callback = pxa2xx_spi_dma_callback;
	rx_desc->callback_param = drv_data;

	dmaengine_submit(rx_desc);
	dmaengine_submit(tx_desc);
	return 0;

err_rx:
	dmaengine_terminate_async(drv_data->controller->dma_tx);
err_tx:
	return err;
}

void pxa2xx_spi_dma_start(struct driver_data *drv_data)
{
	dma_async_issue_pending(drv_data->controller->dma_rx);
	dma_async_issue_pending(drv_data->controller->dma_tx);

	atomic_set(&drv_data->dma_running, 1);
}

void pxa2xx_spi_dma_stop(struct driver_data *drv_data)
{
	atomic_set(&drv_data->dma_running, 0);
	dmaengine_terminate_sync(drv_data->controller->dma_rx);
	dmaengine_terminate_sync(drv_data->controller->dma_tx);
}

int pxa2xx_spi_dma_setup(struct driver_data *drv_data)
{
	struct pxa2xx_spi_controller *pdata = drv_data->controller_info;
	struct spi_controller *controller = drv_data->controller;
	struct device *dev = drv_data->ssp->dev;
	dma_cap_mask_t mask;

	dma_cap_zero(mask);
	dma_cap_set(DMA_SLAVE, mask);

	controller->dma_tx = dma_request_slave_channel_compat(mask,
				pdata->dma_filter, pdata->tx_param, dev, "tx");
	if (!controller->dma_tx)
		return -ENODEV;

	controller->dma_rx = dma_request_slave_channel_compat(mask,
				pdata->dma_filter, pdata->rx_param, dev, "rx");
	if (!controller->dma_rx) {
		dma_release_channel(controller->dma_tx);
		controller->dma_tx = NULL;
		return -ENODEV;
	}

	return 0;
}

void pxa2xx_spi_dma_release(struct driver_data *drv_data)
{
	struct spi_controller *controller = drv_data->controller;

	if (controller->dma_rx) {
		dmaengine_terminate_sync(controller->dma_rx);
		dma_release_channel(controller->dma_rx);
		controller->dma_rx = NULL;
	}
	if (controller->dma_tx) {
		dmaengine_terminate_sync(controller->dma_tx);
		dma_release_channel(controller->dma_tx);
		controller->dma_tx = NULL;
	}
}

int pxa2xx_spi_set_dma_burst_and_threshold(struct chip_data *chip,
					   struct spi_device *spi,
					   u8 bits_per_word, u32 *burst_code,
					   u32 *threshold)
{
	struct pxa2xx_spi_chip *chip_info = spi->controller_data;
	struct driver_data *drv_data = spi_controller_get_devdata(spi->controller);
	u32 dma_burst_size = drv_data->controller_info->dma_burst_size;

	/*
	 * If the DMA burst size is given in chip_info we use that,
	 * otherwise we use the default. Also we use the default FIFO
	 * thresholds for now.
	 */
	*burst_code = chip_info ? chip_info->dma_burst_size : dma_burst_size;
	*threshold = SSCR1_RxTresh(RX_THRESH_DFLT)
		   | SSCR1_TxTresh(TX_THRESH_DFLT);

	return 0;
}
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
5928808e MW	2	/*
	3	* PXA2xx SPI DMA engine support.
	4	*
8083d6b8	5	* Copyright (C) 2013, 2021 Intel Corporation
5928808e	6	* Author: Mika Westerberg <mika.westerberg@linux.intel.com>
5928808e MW	7	*/
5928808e MW	8
5928808e MW	9	#include <linux/device.h>
	10	#include <linux/dma-mapping.h>
	11	#include <linux/dmaengine.h>
5928808e MW	12	#include <linux/scatterlist.h>
5928808e MW	13	#include <linux/sizes.h>
0e476871	14
5928808e	15	#include <linux/spi/pxa2xx_spi.h>
0e476871	16	#include <linux/spi/spi.h>
5928808e MW	17
	18	#include "spi-pxa2xx.h"
	19
5928808e MW	20	static void pxa2xx_spi_dma_transfer_complete(struct driver_data *drv_data,
	21	bool error)
	22	{
51eea52d	23	struct spi_message *msg = drv_data->controller->cur_msg;
5928808e MW	24
	25	/*
	26	* It is possible that one CPU is handling ROR interrupt and other
	27	* just gets DMA completion. Calling pump_transfers() twice for the
	28	* same transfer leads to problems thus we prevent concurrent calls
8083d6b8	29	* by using dma_running.
5928808e MW	30	*/
5928808e MW	31	if (atomic_dec_and_test(&drv_data->dma_running)) {
5928808e MW	32	/*
	33	* If the other CPU is still handling the ROR interrupt we
	34	* might not know about the error yet. So we re-check the
	35	* ROR bit here before we clear the status register.
	36	*/
6d380132 AS	37	if (!error)
6d380132 AS	38	error = read_SSSR_bits(drv_data, drv_data->mask_sr) & SSSR_ROR;
5928808e MW	39
5928808e MW	40	/* Clear status & disable interrupts */
42c80cd4	41	clear_SSCR1_bits(drv_data, drv_data->dma_cr1);
5928808e MW	42	write_SSSR_CS(drv_data, drv_data->clear_sr);
5928808e MW	43	if (!pxa25x_ssp_comp(drv_data))
c039dd27	44	pxa2xx_spi_write(drv_data, SSTO, 0);
5928808e	45
d5898e19	46	if (error) {
5928808e	47	/* In case we got an error we disable the SSP now */
0c8ccd8b	48	pxa_ssp_disable(drv_data->ssp);
d5898e19	49	msg->status = -EIO;
5928808e MW	50	}
5928808e MW	51
51eea52d	52	spi_finalize_current_transfer(drv_data->controller);
5928808e MW	53	}
	54	}
	55
	56	static void pxa2xx_spi_dma_callback(void *data)
	57	{
	58	pxa2xx_spi_dma_transfer_complete(data, false);
	59	}
	60
	61	static struct dma_async_tx_descriptor *
	62	pxa2xx_spi_dma_prepare_one(struct driver_data *drv_data,
d5898e19 JN	63	enum dma_transfer_direction dir,
d5898e19 JN	64	struct spi_transfer *xfer)
5928808e	65	{
96579a4e	66	struct chip_data *chip =
51eea52d	67	spi_get_ctldata(drv_data->controller->cur_msg->spi);
5928808e MW	68	enum dma_slave_buswidth width;
	69	struct dma_slave_config cfg;
	70	struct dma_chan *chan;
	71	struct sg_table *sgt;
b6ced294	72	int ret;
5928808e MW	73
	74	switch (drv_data->n_bytes) {
	75	case 1:
	76	width = DMA_SLAVE_BUSWIDTH_1_BYTE;
	77	break;
	78	case 2:
	79	width = DMA_SLAVE_BUSWIDTH_2_BYTES;
	80	break;
	81	default:
	82	width = DMA_SLAVE_BUSWIDTH_4_BYTES;
	83	break;
	84	}
	85
	86	memset(&cfg, 0, sizeof(cfg));
	87	cfg.direction = dir;
	88
	89	if (dir == DMA_MEM_TO_DEV) {
9e43c9a8	90	cfg.dst_addr = drv_data->ssp->phys_base + SSDR;
5928808e MW	91	cfg.dst_addr_width = width;
5928808e MW	92	cfg.dst_maxburst = chip->dma_burst_size;
5928808e	93
b6ced294	94	sgt = &xfer->tx_sg;
51eea52d	95	chan = drv_data->controller->dma_tx;
5928808e	96	} else {
9e43c9a8	97	cfg.src_addr = drv_data->ssp->phys_base + SSDR;
5928808e MW	98	cfg.src_addr_width = width;
5928808e MW	99	cfg.src_maxburst = chip->dma_burst_size;
5928808e	100
b6ced294	101	sgt = &xfer->rx_sg;
51eea52d	102	chan = drv_data->controller->dma_rx;
5928808e MW	103	}
	104
	105	ret = dmaengine_slave_config(chan, &cfg);
	106	if (ret) {
c3dce24c	107	dev_warn(drv_data->ssp->dev, "DMA slave config failed\n");
5928808e MW	108	return NULL;
	109	}
	110
b6ced294	111	return dmaengine_prep_slave_sg(chan, sgt->sgl, sgt->nents, dir,
5928808e MW	112	DMA_PREP_INTERRUPT \| DMA_CTRL_ACK);
	113	}
	114
5928808e MW	115	irqreturn_t pxa2xx_spi_dma_transfer(struct driver_data *drv_data)
	116	{
	117	u32 status;
	118
6d380132	119	status = read_SSSR_bits(drv_data, drv_data->mask_sr);
5928808e	120	if (status & SSSR_ROR) {
c3dce24c	121	dev_err(drv_data->ssp->dev, "FIFO overrun\n");
5928808e	122
51eea52d LR	123	dmaengine_terminate_async(drv_data->controller->dma_rx);
51eea52d LR	124	dmaengine_terminate_async(drv_data->controller->dma_tx);
5928808e MW	125
	126	pxa2xx_spi_dma_transfer_complete(drv_data, true);
	127	return IRQ_HANDLED;
	128	}
	129
	130	return IRQ_NONE;
	131	}
	132
d5898e19 JN	133	int pxa2xx_spi_dma_prepare(struct driver_data *drv_data,
d5898e19 JN	134	struct spi_transfer *xfer)
5928808e MW	135	{
5928808e MW	136	struct dma_async_tx_descriptor tx_desc, rx_desc;
bffc967e	137	int err;
5928808e	138
d5898e19	139	tx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_MEM_TO_DEV, xfer);
5928808e	140	if (!tx_desc) {
c3dce24c	141	dev_err(drv_data->ssp->dev, "failed to get DMA TX descriptor\n");
7d1f1bf6 AS	142	err = -EBUSY;
7d1f1bf6 AS	143	goto err_tx;
5928808e MW	144	}
5928808e MW	145
d5898e19	146	rx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_DEV_TO_MEM, xfer);
5928808e	147	if (!rx_desc) {
c3dce24c	148	dev_err(drv_data->ssp->dev, "failed to get DMA RX descriptor\n");
7d1f1bf6 AS	149	err = -EBUSY;
7d1f1bf6 AS	150	goto err_rx;
5928808e MW	151	}
	152
	153	/* We are ready when RX completes */
	154	rx_desc->callback = pxa2xx_spi_dma_callback;
	155	rx_desc->callback_param = drv_data;
	156
	157	dmaengine_submit(rx_desc);
	158	dmaengine_submit(tx_desc);
	159	return 0;
7d1f1bf6 AS	160
7d1f1bf6 AS	161	err_rx:
51eea52d	162	dmaengine_terminate_async(drv_data->controller->dma_tx);
7d1f1bf6	163	err_tx:
7d1f1bf6	164	return err;
5928808e MW	165	}
	166
	167	void pxa2xx_spi_dma_start(struct driver_data *drv_data)
	168	{
51eea52d LR	169	dma_async_issue_pending(drv_data->controller->dma_rx);
51eea52d LR	170	dma_async_issue_pending(drv_data->controller->dma_tx);
5928808e MW	171
	172	atomic_set(&drv_data->dma_running, 1);
	173	}
	174
d5898e19 JN	175	void pxa2xx_spi_dma_stop(struct driver_data *drv_data)
	176	{
	177	atomic_set(&drv_data->dma_running, 0);
51eea52d LR	178	dmaengine_terminate_sync(drv_data->controller->dma_rx);
51eea52d LR	179	dmaengine_terminate_sync(drv_data->controller->dma_tx);
d5898e19 JN	180	}
d5898e19 JN	181
5928808e MW	182	int pxa2xx_spi_dma_setup(struct driver_data *drv_data)
5928808e MW	183	{
51eea52d	184	struct pxa2xx_spi_controller *pdata = drv_data->controller_info;
51eea52d	185	struct spi_controller *controller = drv_data->controller;
c3dce24c	186	struct device *dev = drv_data->ssp->dev;
5928808e MW	187	dma_cap_mask_t mask;
	188
	189	dma_cap_zero(mask);
	190	dma_cap_set(DMA_SLAVE, mask);
	191
51eea52d	192	controller->dma_tx = dma_request_slave_channel_compat(mask,
b729bf34	193	pdata->dma_filter, pdata->tx_param, dev, "tx");
51eea52d	194	if (!controller->dma_tx)
5928808e MW	195	return -ENODEV;
5928808e MW	196
51eea52d	197	controller->dma_rx = dma_request_slave_channel_compat(mask,
b729bf34	198	pdata->dma_filter, pdata->rx_param, dev, "rx");
51eea52d LR	199	if (!controller->dma_rx) {
	200	dma_release_channel(controller->dma_tx);
	201	controller->dma_tx = NULL;
5928808e MW	202	return -ENODEV;
	203	}
	204
	205	return 0;
	206	}
	207
	208	void pxa2xx_spi_dma_release(struct driver_data *drv_data)
	209	{
51eea52d	210	struct spi_controller *controller = drv_data->controller;
b6ced294	211
51eea52d LR	212	if (controller->dma_rx) {
	213	dmaengine_terminate_sync(controller->dma_rx);
	214	dma_release_channel(controller->dma_rx);
	215	controller->dma_rx = NULL;
5928808e	216	}
51eea52d LR	217	if (controller->dma_tx) {
	218	dmaengine_terminate_sync(controller->dma_tx);
	219	dma_release_channel(controller->dma_tx);
	220	controller->dma_tx = NULL;
5928808e MW	221	}
	222	}
	223
5928808e MW	224	int pxa2xx_spi_set_dma_burst_and_threshold(struct chip_data *chip,
	225	struct spi_device *spi,
	226	u8 bits_per_word, u32 *burst_code,
	227	u32 *threshold)
	228	{
	229	struct pxa2xx_spi_chip *chip_info = spi->controller_data;
37821a82 AS	230	struct driver_data *drv_data = spi_controller_get_devdata(spi->controller);
37821a82 AS	231	u32 dma_burst_size = drv_data->controller_info->dma_burst_size;
5928808e MW	232
	233	/*
	234	* If the DMA burst size is given in chip_info we use that,
	235	* otherwise we use the default. Also we use the default FIFO
	236	* thresholds for now.
	237	*/
37821a82	238	*burst_code = chip_info ? chip_info->dma_burst_size : dma_burst_size;
5928808e MW	239	*threshold = SSCR1_RxTresh(RX_THRESH_DFLT)
	240	\| SSCR1_TxTresh(TX_THRESH_DFLT);
	241
	242	return 0;
	243	}