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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * PXA2xx SPI DMA engine support.
4 *
5 * Copyright (C) 2013, 2021 Intel Corporation
6 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
7 */
8
9#include <linux/device.h>
10#include <linux/dma-mapping.h>
11#include <linux/dmaengine.h>
12#include <linux/scatterlist.h>
13#include <linux/sizes.h>
14
15#include <linux/spi/pxa2xx_spi.h>
16#include <linux/spi/spi.h>
17
18#include "spi-pxa2xx.h"
19
20static void pxa2xx_spi_dma_transfer_complete(struct driver_data *drv_data,
21 bool error)
22{
23 struct spi_message *msg = drv_data->controller->cur_msg;
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
29 * by using dma_running.
30 */
31 if (atomic_dec_and_test(&drv_data->dma_running)) {
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 */
37 if (!error)
38 error = read_SSSR_bits(drv_data, drv_data->mask_sr) & SSSR_ROR;
39
40 /* Clear status & disable interrupts */
41 clear_SSCR1_bits(drv_data, drv_data->dma_cr1);
42 write_SSSR_CS(drv_data, drv_data->clear_sr);
43 if (!pxa25x_ssp_comp(drv_data))
44 pxa2xx_spi_write(drv_data, SSTO, 0);
45
46 if (error) {
47 /* In case we got an error we disable the SSP now */
48 pxa_ssp_disable(drv_data->ssp);
49 msg->status = -EIO;
50 }
51
52 spi_finalize_current_transfer(drv_data->controller);
53 }
54}
55
56static void pxa2xx_spi_dma_callback(void *data)
57{
58 pxa2xx_spi_dma_transfer_complete(data, false);
59}
60
61static struct dma_async_tx_descriptor *
62pxa2xx_spi_dma_prepare_one(struct driver_data *drv_data,
63 enum dma_transfer_direction dir,
64 struct spi_transfer *xfer)
65{
66 struct chip_data *chip =
67 spi_get_ctldata(drv_data->controller->cur_msg->spi);
68 enum dma_slave_buswidth width;
69 struct dma_slave_config cfg;
70 struct dma_chan *chan;
71 struct sg_table *sgt;
72 int ret;
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) {
90 cfg.dst_addr = drv_data->ssp->phys_base + SSDR;
91 cfg.dst_addr_width = width;
92 cfg.dst_maxburst = chip->dma_burst_size;
93
94 sgt = &xfer->tx_sg;
95 chan = drv_data->controller->dma_tx;
96 } else {
97 cfg.src_addr = drv_data->ssp->phys_base + SSDR;
98 cfg.src_addr_width = width;
99 cfg.src_maxburst = chip->dma_burst_size;
100
101 sgt = &xfer->rx_sg;
102 chan = drv_data->controller->dma_rx;
103 }
104
105 ret = dmaengine_slave_config(chan, &cfg);
106 if (ret) {
107 dev_warn(drv_data->ssp->dev, "DMA slave config failed\n");
108 return NULL;
109 }
110
111 return dmaengine_prep_slave_sg(chan, sgt->sgl, sgt->nents, dir,
112 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
113}
114
115irqreturn_t pxa2xx_spi_dma_transfer(struct driver_data *drv_data)
116{
117 u32 status;
118
119 status = read_SSSR_bits(drv_data, drv_data->mask_sr);
120 if (status & SSSR_ROR) {
121 dev_err(drv_data->ssp->dev, "FIFO overrun\n");
122
123 dmaengine_terminate_async(drv_data->controller->dma_rx);
124 dmaengine_terminate_async(drv_data->controller->dma_tx);
125
126 pxa2xx_spi_dma_transfer_complete(drv_data, true);
127 return IRQ_HANDLED;
128 }
129
130 return IRQ_NONE;
131}
132
133int pxa2xx_spi_dma_prepare(struct driver_data *drv_data,
134 struct spi_transfer *xfer)
135{
136 struct dma_async_tx_descriptor *tx_desc, *rx_desc;
137 int err;
138
139 tx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_MEM_TO_DEV, xfer);
140 if (!tx_desc) {
141 dev_err(drv_data->ssp->dev, "failed to get DMA TX descriptor\n");
142 err = -EBUSY;
143 goto err_tx;
144 }
145
146 rx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_DEV_TO_MEM, xfer);
147 if (!rx_desc) {
148 dev_err(drv_data->ssp->dev, "failed to get DMA RX descriptor\n");
149 err = -EBUSY;
150 goto err_rx;
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;
160
161err_rx:
162 dmaengine_terminate_async(drv_data->controller->dma_tx);
163err_tx:
164 return err;
165}
166
167void pxa2xx_spi_dma_start(struct driver_data *drv_data)
168{
169 dma_async_issue_pending(drv_data->controller->dma_rx);
170 dma_async_issue_pending(drv_data->controller->dma_tx);
171
172 atomic_set(&drv_data->dma_running, 1);
173}
174
175void pxa2xx_spi_dma_stop(struct driver_data *drv_data)
176{
177 atomic_set(&drv_data->dma_running, 0);
178 dmaengine_terminate_sync(drv_data->controller->dma_rx);
179 dmaengine_terminate_sync(drv_data->controller->dma_tx);
180}
181
182int pxa2xx_spi_dma_setup(struct driver_data *drv_data)
183{
184 struct pxa2xx_spi_controller *pdata = drv_data->controller_info;
185 struct spi_controller *controller = drv_data->controller;
186 struct device *dev = drv_data->ssp->dev;
187 dma_cap_mask_t mask;
188
189 dma_cap_zero(mask);
190 dma_cap_set(DMA_SLAVE, mask);
191
192 controller->dma_tx = dma_request_slave_channel_compat(mask,
193 pdata->dma_filter, pdata->tx_param, dev, "tx");
194 if (!controller->dma_tx)
195 return -ENODEV;
196
197 controller->dma_rx = dma_request_slave_channel_compat(mask,
198 pdata->dma_filter, pdata->rx_param, dev, "rx");
199 if (!controller->dma_rx) {
200 dma_release_channel(controller->dma_tx);
201 controller->dma_tx = NULL;
202 return -ENODEV;
203 }
204
205 return 0;
206}
207
208void pxa2xx_spi_dma_release(struct driver_data *drv_data)
209{
210 struct spi_controller *controller = drv_data->controller;
211
212 if (controller->dma_rx) {
213 dmaengine_terminate_sync(controller->dma_rx);
214 dma_release_channel(controller->dma_rx);
215 controller->dma_rx = NULL;
216 }
217 if (controller->dma_tx) {
218 dmaengine_terminate_sync(controller->dma_tx);
219 dma_release_channel(controller->dma_tx);
220 controller->dma_tx = NULL;
221 }
222}
223
224int 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;
230 struct driver_data *drv_data = spi_controller_get_devdata(spi->controller);
231 u32 dma_burst_size = drv_data->controller_info->dma_burst_size;
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 */
238 *burst_code = chip_info ? chip_info->dma_burst_size : dma_burst_size;
239 *threshold = SSCR1_RxTresh(RX_THRESH_DFLT)
240 | SSCR1_TxTresh(TX_THRESH_DFLT);
241
242 return 0;
243}
1/*
2 * PXA2xx SPI DMA engine support.
3 *
4 * Copyright (C) 2013, Intel Corporation
5 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/device.h>
13#include <linux/dma-mapping.h>
14#include <linux/dmaengine.h>
15#include <linux/pxa2xx_ssp.h>
16#include <linux/scatterlist.h>
17#include <linux/sizes.h>
18#include <linux/spi/spi.h>
19#include <linux/spi/pxa2xx_spi.h>
20
21#include "spi-pxa2xx.h"
22
23static void pxa2xx_spi_dma_transfer_complete(struct driver_data *drv_data,
24 bool error)
25{
26 struct spi_message *msg = drv_data->master->cur_msg;
27
28 /*
29 * It is possible that one CPU is handling ROR interrupt and other
30 * just gets DMA completion. Calling pump_transfers() twice for the
31 * same transfer leads to problems thus we prevent concurrent calls
32 * by using ->dma_running.
33 */
34 if (atomic_dec_and_test(&drv_data->dma_running)) {
35 /*
36 * If the other CPU is still handling the ROR interrupt we
37 * might not know about the error yet. So we re-check the
38 * ROR bit here before we clear the status register.
39 */
40 if (!error) {
41 u32 status = pxa2xx_spi_read(drv_data, SSSR)
42 & drv_data->mask_sr;
43 error = status & SSSR_ROR;
44 }
45
46 /* Clear status & disable interrupts */
47 pxa2xx_spi_write(drv_data, SSCR1,
48 pxa2xx_spi_read(drv_data, SSCR1)
49 & ~drv_data->dma_cr1);
50 write_SSSR_CS(drv_data, drv_data->clear_sr);
51 if (!pxa25x_ssp_comp(drv_data))
52 pxa2xx_spi_write(drv_data, SSTO, 0);
53
54 if (!error) {
55 msg->actual_length += drv_data->len;
56 msg->state = pxa2xx_spi_next_transfer(drv_data);
57 } else {
58 /* In case we got an error we disable the SSP now */
59 pxa2xx_spi_write(drv_data, SSCR0,
60 pxa2xx_spi_read(drv_data, SSCR0)
61 & ~SSCR0_SSE);
62
63 msg->state = ERROR_STATE;
64 }
65
66 tasklet_schedule(&drv_data->pump_transfers);
67 }
68}
69
70static void pxa2xx_spi_dma_callback(void *data)
71{
72 pxa2xx_spi_dma_transfer_complete(data, false);
73}
74
75static struct dma_async_tx_descriptor *
76pxa2xx_spi_dma_prepare_one(struct driver_data *drv_data,
77 enum dma_transfer_direction dir)
78{
79 struct chip_data *chip =
80 spi_get_ctldata(drv_data->master->cur_msg->spi);
81 struct spi_transfer *xfer = drv_data->cur_transfer;
82 enum dma_slave_buswidth width;
83 struct dma_slave_config cfg;
84 struct dma_chan *chan;
85 struct sg_table *sgt;
86 int ret;
87
88 switch (drv_data->n_bytes) {
89 case 1:
90 width = DMA_SLAVE_BUSWIDTH_1_BYTE;
91 break;
92 case 2:
93 width = DMA_SLAVE_BUSWIDTH_2_BYTES;
94 break;
95 default:
96 width = DMA_SLAVE_BUSWIDTH_4_BYTES;
97 break;
98 }
99
100 memset(&cfg, 0, sizeof(cfg));
101 cfg.direction = dir;
102
103 if (dir == DMA_MEM_TO_DEV) {
104 cfg.dst_addr = drv_data->ssdr_physical;
105 cfg.dst_addr_width = width;
106 cfg.dst_maxburst = chip->dma_burst_size;
107
108 sgt = &xfer->tx_sg;
109 chan = drv_data->master->dma_tx;
110 } else {
111 cfg.src_addr = drv_data->ssdr_physical;
112 cfg.src_addr_width = width;
113 cfg.src_maxburst = chip->dma_burst_size;
114
115 sgt = &xfer->rx_sg;
116 chan = drv_data->master->dma_rx;
117 }
118
119 ret = dmaengine_slave_config(chan, &cfg);
120 if (ret) {
121 dev_warn(&drv_data->pdev->dev, "DMA slave config failed\n");
122 return NULL;
123 }
124
125 return dmaengine_prep_slave_sg(chan, sgt->sgl, sgt->nents, dir,
126 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
127}
128
129irqreturn_t pxa2xx_spi_dma_transfer(struct driver_data *drv_data)
130{
131 u32 status;
132
133 status = pxa2xx_spi_read(drv_data, SSSR) & drv_data->mask_sr;
134 if (status & SSSR_ROR) {
135 dev_err(&drv_data->pdev->dev, "FIFO overrun\n");
136
137 dmaengine_terminate_async(drv_data->master->dma_rx);
138 dmaengine_terminate_async(drv_data->master->dma_tx);
139
140 pxa2xx_spi_dma_transfer_complete(drv_data, true);
141 return IRQ_HANDLED;
142 }
143
144 return IRQ_NONE;
145}
146
147int pxa2xx_spi_dma_prepare(struct driver_data *drv_data, u32 dma_burst)
148{
149 struct dma_async_tx_descriptor *tx_desc, *rx_desc;
150 int err;
151
152 tx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_MEM_TO_DEV);
153 if (!tx_desc) {
154 dev_err(&drv_data->pdev->dev,
155 "failed to get DMA TX descriptor\n");
156 err = -EBUSY;
157 goto err_tx;
158 }
159
160 rx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_DEV_TO_MEM);
161 if (!rx_desc) {
162 dev_err(&drv_data->pdev->dev,
163 "failed to get DMA RX descriptor\n");
164 err = -EBUSY;
165 goto err_rx;
166 }
167
168 /* We are ready when RX completes */
169 rx_desc->callback = pxa2xx_spi_dma_callback;
170 rx_desc->callback_param = drv_data;
171
172 dmaengine_submit(rx_desc);
173 dmaengine_submit(tx_desc);
174 return 0;
175
176err_rx:
177 dmaengine_terminate_async(drv_data->master->dma_tx);
178err_tx:
179 return err;
180}
181
182void pxa2xx_spi_dma_start(struct driver_data *drv_data)
183{
184 dma_async_issue_pending(drv_data->master->dma_rx);
185 dma_async_issue_pending(drv_data->master->dma_tx);
186
187 atomic_set(&drv_data->dma_running, 1);
188}
189
190int pxa2xx_spi_dma_setup(struct driver_data *drv_data)
191{
192 struct pxa2xx_spi_master *pdata = drv_data->master_info;
193 struct device *dev = &drv_data->pdev->dev;
194 struct spi_controller *master = drv_data->master;
195 dma_cap_mask_t mask;
196
197 dma_cap_zero(mask);
198 dma_cap_set(DMA_SLAVE, mask);
199
200 master->dma_tx = dma_request_slave_channel_compat(mask,
201 pdata->dma_filter, pdata->tx_param, dev, "tx");
202 if (!master->dma_tx)
203 return -ENODEV;
204
205 master->dma_rx = dma_request_slave_channel_compat(mask,
206 pdata->dma_filter, pdata->rx_param, dev, "rx");
207 if (!master->dma_rx) {
208 dma_release_channel(master->dma_tx);
209 master->dma_tx = NULL;
210 return -ENODEV;
211 }
212
213 return 0;
214}
215
216void pxa2xx_spi_dma_release(struct driver_data *drv_data)
217{
218 struct spi_controller *master = drv_data->master;
219
220 if (master->dma_rx) {
221 dmaengine_terminate_sync(master->dma_rx);
222 dma_release_channel(master->dma_rx);
223 master->dma_rx = NULL;
224 }
225 if (master->dma_tx) {
226 dmaengine_terminate_sync(master->dma_tx);
227 dma_release_channel(master->dma_tx);
228 master->dma_tx = NULL;
229 }
230}
231
232int pxa2xx_spi_set_dma_burst_and_threshold(struct chip_data *chip,
233 struct spi_device *spi,
234 u8 bits_per_word, u32 *burst_code,
235 u32 *threshold)
236{
237 struct pxa2xx_spi_chip *chip_info = spi->controller_data;
238
239 /*
240 * If the DMA burst size is given in chip_info we use that,
241 * otherwise we use the default. Also we use the default FIFO
242 * thresholds for now.
243 */
244 *burst_code = chip_info ? chip_info->dma_burst_size : 1;
245 *threshold = SSCR1_RxTresh(RX_THRESH_DFLT)
246 | SSCR1_TxTresh(TX_THRESH_DFLT);
247
248 return 0;
249}