1// SPDX-License-Identifier: GPL-2.0
2//
3// Copyright (C) 2019 Linaro Ltd.
4// Copyright (C) 2019 Socionext Inc.
5
6#include <linux/bits.h>
7#include <linux/dma-mapping.h>
8#include <linux/dmaengine.h>
9#include <linux/interrupt.h>
10#include <linux/iopoll.h>
11#include <linux/list.h>
12#include <linux/module.h>
13#include <linux/of_dma.h>
14#include <linux/platform_device.h>
15#include <linux/slab.h>
16#include <linux/types.h>
17#include <linux/bitfield.h>
18
19#include "virt-dma.h"
20
21/* global register */
22#define M10V_XDACS 0x00
23
24/* channel local register */
25#define M10V_XDTBC 0x10
26#define M10V_XDSSA 0x14
27#define M10V_XDDSA 0x18
28#define M10V_XDSAC 0x1C
29#define M10V_XDDAC 0x20
30#define M10V_XDDCC 0x24
31#define M10V_XDDES 0x28
32#define M10V_XDDPC 0x2C
33#define M10V_XDDSD 0x30
34
35#define M10V_XDACS_XE BIT(28)
36
37#define M10V_DEFBS	0x3
38#define M10V_DEFBL	0xf
39
40#define M10V_XDSAC_SBS	GENMASK(17, 16)
41#define M10V_XDSAC_SBL	GENMASK(11, 8)
42
43#define M10V_XDDAC_DBS	GENMASK(17, 16)
44#define M10V_XDDAC_DBL	GENMASK(11, 8)
45
46#define M10V_XDDES_CE	BIT(28)
47#define M10V_XDDES_SE	BIT(24)
48#define M10V_XDDES_SA	BIT(15)
49#define M10V_XDDES_TF	GENMASK(23, 20)
50#define M10V_XDDES_EI	BIT(1)
51#define M10V_XDDES_TI	BIT(0)
52
53#define M10V_XDDSD_IS_MASK	GENMASK(3, 0)
54#define M10V_XDDSD_IS_NORMAL	0x8
55
56#define MLB_XDMAC_BUSWIDTHS	(BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
57				 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
58				 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
59				 BIT(DMA_SLAVE_BUSWIDTH_8_BYTES))
60
61struct milbeaut_xdmac_desc {
62	struct virt_dma_desc vd;
63	size_t len;
64	dma_addr_t src;
65	dma_addr_t dst;
66};
67
68struct milbeaut_xdmac_chan {
69	struct virt_dma_chan vc;
70	struct milbeaut_xdmac_desc *md;
71	void __iomem *reg_ch_base;
72};
73
74struct milbeaut_xdmac_device {
75	struct dma_device ddev;
76	void __iomem *reg_base;
77	struct milbeaut_xdmac_chan channels[];
78};
79
80static struct milbeaut_xdmac_chan *
81to_milbeaut_xdmac_chan(struct virt_dma_chan *vc)
82{
83	return container_of(vc, struct milbeaut_xdmac_chan, vc);
84}
85
86static struct milbeaut_xdmac_desc *
87to_milbeaut_xdmac_desc(struct virt_dma_desc *vd)
88{
89	return container_of(vd, struct milbeaut_xdmac_desc, vd);
90}
91
92/* mc->vc.lock must be held by caller */
93static struct milbeaut_xdmac_desc *
94milbeaut_xdmac_next_desc(struct milbeaut_xdmac_chan *mc)
95{
96	struct virt_dma_desc *vd;
97
98	vd = vchan_next_desc(&mc->vc);
99	if (!vd) {
100		mc->md = NULL;
101		return NULL;
102	}
103
104	list_del(&vd->node);
105
106	mc->md = to_milbeaut_xdmac_desc(vd);
107
108	return mc->md;
109}
110
111/* mc->vc.lock must be held by caller */
112static void milbeaut_chan_start(struct milbeaut_xdmac_chan *mc,
113				struct milbeaut_xdmac_desc *md)
114{
115	u32 val;
116
117	/* Setup the channel */
118	val = md->len - 1;
119	writel_relaxed(val, mc->reg_ch_base + M10V_XDTBC);
120
121	val = md->src;
122	writel_relaxed(val, mc->reg_ch_base + M10V_XDSSA);
123
124	val = md->dst;
125	writel_relaxed(val, mc->reg_ch_base + M10V_XDDSA);
126
127	val = readl_relaxed(mc->reg_ch_base + M10V_XDSAC);
128	val &= ~(M10V_XDSAC_SBS | M10V_XDSAC_SBL);
129	val |= FIELD_PREP(M10V_XDSAC_SBS, M10V_DEFBS) |
130		FIELD_PREP(M10V_XDSAC_SBL, M10V_DEFBL);
131	writel_relaxed(val, mc->reg_ch_base + M10V_XDSAC);
132
133	val = readl_relaxed(mc->reg_ch_base + M10V_XDDAC);
134	val &= ~(M10V_XDDAC_DBS | M10V_XDDAC_DBL);
135	val |= FIELD_PREP(M10V_XDDAC_DBS, M10V_DEFBS) |
136		FIELD_PREP(M10V_XDDAC_DBL, M10V_DEFBL);
137	writel_relaxed(val, mc->reg_ch_base + M10V_XDDAC);
138
139	/* Start the channel */
140	val = readl_relaxed(mc->reg_ch_base + M10V_XDDES);
141	val &= ~(M10V_XDDES_CE | M10V_XDDES_SE | M10V_XDDES_TF |
142		 M10V_XDDES_EI | M10V_XDDES_TI);
143	val |= FIELD_PREP(M10V_XDDES_CE, 1) | FIELD_PREP(M10V_XDDES_SE, 1) |
144		FIELD_PREP(M10V_XDDES_TF, 1) | FIELD_PREP(M10V_XDDES_EI, 1) |
145		FIELD_PREP(M10V_XDDES_TI, 1);
146	writel_relaxed(val, mc->reg_ch_base + M10V_XDDES);
147}
148
149/* mc->vc.lock must be held by caller */
150static void milbeaut_xdmac_start(struct milbeaut_xdmac_chan *mc)
151{
152	struct milbeaut_xdmac_desc *md;
153
154	md = milbeaut_xdmac_next_desc(mc);
155	if (md)
156		milbeaut_chan_start(mc, md);
157}
158
159static irqreturn_t milbeaut_xdmac_interrupt(int irq, void *dev_id)
160{
161	struct milbeaut_xdmac_chan *mc = dev_id;
162	struct milbeaut_xdmac_desc *md;
163	u32 val;
164
165	spin_lock(&mc->vc.lock);
166
167	/* Ack and Stop */
168	val = FIELD_PREP(M10V_XDDSD_IS_MASK, 0x0);
169	writel_relaxed(val, mc->reg_ch_base + M10V_XDDSD);
170
171	md = mc->md;
172	if (!md)
173		goto out;
174
175	vchan_cookie_complete(&md->vd);
176
177	milbeaut_xdmac_start(mc);
178out:
179	spin_unlock(&mc->vc.lock);
180	return IRQ_HANDLED;
181}
182
183static void milbeaut_xdmac_free_chan_resources(struct dma_chan *chan)
184{
185	vchan_free_chan_resources(to_virt_chan(chan));
186}
187
188static struct dma_async_tx_descriptor *
189milbeaut_xdmac_prep_memcpy(struct dma_chan *chan, dma_addr_t dst,
190			   dma_addr_t src, size_t len, unsigned long flags)
191{
192	struct virt_dma_chan *vc = to_virt_chan(chan);
193	struct milbeaut_xdmac_desc *md;
194
195	md = kzalloc(sizeof(*md), GFP_NOWAIT);
196	if (!md)
197		return NULL;
198
199	md->len = len;
200	md->src = src;
201	md->dst = dst;
202
203	return vchan_tx_prep(vc, &md->vd, flags);
204}
205
206static int milbeaut_xdmac_terminate_all(struct dma_chan *chan)
207{
208	struct virt_dma_chan *vc = to_virt_chan(chan);
209	struct milbeaut_xdmac_chan *mc = to_milbeaut_xdmac_chan(vc);
210	unsigned long flags;
211	u32 val;
212
213	LIST_HEAD(head);
214
215	spin_lock_irqsave(&vc->lock, flags);
216
217	/* Halt the channel */
218	val = readl(mc->reg_ch_base + M10V_XDDES);
219	val &= ~M10V_XDDES_CE;
220	val |= FIELD_PREP(M10V_XDDES_CE, 0);
221	writel(val, mc->reg_ch_base + M10V_XDDES);
222
223	if (mc->md) {
224		vchan_terminate_vdesc(&mc->md->vd);
225		mc->md = NULL;
226	}
227
228	vchan_get_all_descriptors(vc, &head);
229
230	spin_unlock_irqrestore(&vc->lock, flags);
231
232	vchan_dma_desc_free_list(vc, &head);
233
234	return 0;
235}
236
237static void milbeaut_xdmac_synchronize(struct dma_chan *chan)
238{
239	vchan_synchronize(to_virt_chan(chan));
240}
241
242static void milbeaut_xdmac_issue_pending(struct dma_chan *chan)
243{
244	struct virt_dma_chan *vc = to_virt_chan(chan);
245	struct milbeaut_xdmac_chan *mc = to_milbeaut_xdmac_chan(vc);
246	unsigned long flags;
247
248	spin_lock_irqsave(&vc->lock, flags);
249
250	if (vchan_issue_pending(vc) && !mc->md)
251		milbeaut_xdmac_start(mc);
252
253	spin_unlock_irqrestore(&vc->lock, flags);
254}
255
256static void milbeaut_xdmac_desc_free(struct virt_dma_desc *vd)
257{
258	kfree(to_milbeaut_xdmac_desc(vd));
259}
260
261static int milbeaut_xdmac_chan_init(struct platform_device *pdev,
262				    struct milbeaut_xdmac_device *mdev,
263				    int chan_id)
264{
265	struct device *dev = &pdev->dev;
266	struct milbeaut_xdmac_chan *mc = &mdev->channels[chan_id];
267	char *irq_name;
268	int irq, ret;
269
270	irq = platform_get_irq(pdev, chan_id);
271	if (irq < 0)
272		return irq;
273
274	irq_name = devm_kasprintf(dev, GFP_KERNEL, "milbeaut-xdmac-%d",
275				  chan_id);
276	if (!irq_name)
277		return -ENOMEM;
278
279	ret = devm_request_irq(dev, irq, milbeaut_xdmac_interrupt,
280			       IRQF_SHARED, irq_name, mc);
281	if (ret)
282		return ret;
283
284	mc->reg_ch_base = mdev->reg_base + chan_id * 0x30;
285
286	mc->vc.desc_free = milbeaut_xdmac_desc_free;
287	vchan_init(&mc->vc, &mdev->ddev);
288
289	return 0;
290}
291
292static void enable_xdmac(struct milbeaut_xdmac_device *mdev)
293{
294	unsigned int val;
295
296	val = readl(mdev->reg_base + M10V_XDACS);
297	val |= M10V_XDACS_XE;
298	writel(val, mdev->reg_base + M10V_XDACS);
299}
300
301static void disable_xdmac(struct milbeaut_xdmac_device *mdev)
302{
303	unsigned int val;
304
305	val = readl(mdev->reg_base + M10V_XDACS);
306	val &= ~M10V_XDACS_XE;
307	writel(val, mdev->reg_base + M10V_XDACS);
308}
309
310static int milbeaut_xdmac_probe(struct platform_device *pdev)
311{
312	struct device *dev = &pdev->dev;
313	struct milbeaut_xdmac_device *mdev;
314	struct dma_device *ddev;
315	int nr_chans, ret, i;
316
317	nr_chans = platform_irq_count(pdev);
318	if (nr_chans < 0)
319		return nr_chans;
320
321	mdev = devm_kzalloc(dev, struct_size(mdev, channels, nr_chans),
322			    GFP_KERNEL);
323	if (!mdev)
324		return -ENOMEM;
325
326	mdev->reg_base = devm_platform_ioremap_resource(pdev, 0);
327	if (IS_ERR(mdev->reg_base))
328		return PTR_ERR(mdev->reg_base);
329
330	ddev = &mdev->ddev;
331	ddev->dev = dev;
332	dma_cap_set(DMA_MEMCPY, ddev->cap_mask);
333	ddev->src_addr_widths = MLB_XDMAC_BUSWIDTHS;
334	ddev->dst_addr_widths = MLB_XDMAC_BUSWIDTHS;
335	ddev->device_free_chan_resources = milbeaut_xdmac_free_chan_resources;
336	ddev->device_prep_dma_memcpy = milbeaut_xdmac_prep_memcpy;
337	ddev->device_terminate_all = milbeaut_xdmac_terminate_all;
338	ddev->device_synchronize = milbeaut_xdmac_synchronize;
339	ddev->device_tx_status = dma_cookie_status;
340	ddev->device_issue_pending = milbeaut_xdmac_issue_pending;
341	INIT_LIST_HEAD(&ddev->channels);
342
343	for (i = 0; i < nr_chans; i++) {
344		ret = milbeaut_xdmac_chan_init(pdev, mdev, i);
345		if (ret)
346			return ret;
347	}
348
349	enable_xdmac(mdev);
350
351	ret = dma_async_device_register(ddev);
352	if (ret)
353		goto disable_xdmac;
354
355	ret = of_dma_controller_register(dev->of_node,
356					 of_dma_simple_xlate, mdev);
357	if (ret)
358		goto unregister_dmac;
359
360	platform_set_drvdata(pdev, mdev);
361
362	return 0;
363
364unregister_dmac:
365	dma_async_device_unregister(ddev);
366disable_xdmac:
367	disable_xdmac(mdev);
368	return ret;
369}
370
371static void milbeaut_xdmac_remove(struct platform_device *pdev)
372{
373	struct milbeaut_xdmac_device *mdev = platform_get_drvdata(pdev);
374	struct dma_chan *chan;
375	int ret;
376
377	/*
378	 * Before reaching here, almost all descriptors have been freed by the
379	 * ->device_free_chan_resources() hook. However, each channel might
380	 * be still holding one descriptor that was on-flight at that moment.
381	 * Terminate it to make sure this hardware is no longer running. Then,
382	 * free the channel resources once again to avoid memory leak.
383	 */
384	list_for_each_entry(chan, &mdev->ddev.channels, device_node) {
385		ret = dmaengine_terminate_sync(chan);
386		if (ret) {
387			/*
388			 * This results in resource leakage and maybe also
389			 * use-after-free errors as e.g. *mdev is kfreed.
390			 */
391			dev_alert(&pdev->dev, "Failed to terminate channel %d (%pe)\n",
392				  chan->chan_id, ERR_PTR(ret));
393			return;
394		}
395		milbeaut_xdmac_free_chan_resources(chan);
396	}
397
398	of_dma_controller_free(pdev->dev.of_node);
399	dma_async_device_unregister(&mdev->ddev);
400
401	disable_xdmac(mdev);
402}
403
404static const struct of_device_id milbeaut_xdmac_match[] = {
405	{ .compatible = "socionext,milbeaut-m10v-xdmac" },
406	{ /* sentinel */ }
407};
408MODULE_DEVICE_TABLE(of, milbeaut_xdmac_match);
409
410static struct platform_driver milbeaut_xdmac_driver = {
411	.probe = milbeaut_xdmac_probe,
412	.remove_new = milbeaut_xdmac_remove,
413	.driver = {
414		.name = "milbeaut-m10v-xdmac",
415		.of_match_table = milbeaut_xdmac_match,
416	},
417};
418module_platform_driver(milbeaut_xdmac_driver);
419
420MODULE_DESCRIPTION("Milbeaut XDMAC DmaEngine driver");
421MODULE_LICENSE("GPL v2");
422