1 // SPDX-License-Identifier: GPL-2.0
3 * MediaTek UART APDMA driver.
5 * Copyright (c) 2019 MediaTek Inc.
6 * Author: Long Cheng <long.cheng@mediatek.com>
10 #include <linux/dmaengine.h>
11 #include <linux/dma-mapping.h>
12 #include <linux/err.h>
13 #include <linux/init.h>
14 #include <linux/interrupt.h>
15 #include <linux/iopoll.h>
16 #include <linux/kernel.h>
17 #include <linux/list.h>
18 #include <linux/module.h>
19 #include <linux/of_dma.h>
20 #include <linux/platform_device.h>
21 #include <linux/pm_runtime.h>
22 #include <linux/slab.h>
23 #include <linux/spinlock.h>
25 #include "../virt-dma.h"
27 /* The default number of virtual channel */
28 #define MTK_UART_APDMA_NR_VCHANS 8
30 #define VFF_EN_B BIT(0)
31 #define VFF_STOP_B BIT(0)
32 #define VFF_FLUSH_B BIT(0)
33 #define VFF_4G_EN_B BIT(0)
34 /* rx valid size >= vff thre */
35 #define VFF_RX_INT_EN_B (BIT(0) | BIT(1))
36 /* tx left size >= vff thre */
37 #define VFF_TX_INT_EN_B BIT(0)
38 #define VFF_WARM_RST_B BIT(0)
39 #define VFF_RX_INT_CLR_B (BIT(0) | BIT(1))
40 #define VFF_TX_INT_CLR_B 0
41 #define VFF_STOP_CLR_B 0
42 #define VFF_EN_CLR_B 0
43 #define VFF_INT_EN_CLR_B 0
44 #define VFF_4G_SUPPORT_CLR_B 0
47 * interrupt trigger level for tx
48 * if threshold is n, no polling is required to start tx.
49 * otherwise need polling VFF_FLUSH.
51 #define VFF_TX_THRE(n) (n)
52 /* interrupt trigger level for rx */
53 #define VFF_RX_THRE(n) ((n) * 3 / 4)
55 #define VFF_RING_SIZE 0xffff
56 /* invert this bit when wrap ring head again */
57 #define VFF_RING_WRAP 0x10000
59 #define VFF_INT_FLAG 0x00
60 #define VFF_INT_EN 0x04
64 #define VFF_FLUSH 0x14
70 /* TX: the buffer size HW can read. RX: the buffer size SW can read. */
71 #define VFF_VALID_SIZE 0x3c
72 /* TX: the buffer size SW can write. RX: the buffer size HW can write. */
73 #define VFF_LEFT_SIZE 0x40
74 #define VFF_DEBUG_STATUS 0x50
75 #define VFF_4G_SUPPORT 0x54
77 struct mtk_uart_apdmadev {
78 struct dma_device ddev;
81 unsigned int dma_requests;
84 struct mtk_uart_apdma_desc {
85 struct virt_dma_desc vd;
88 unsigned int avail_len;
92 struct virt_dma_chan vc;
93 struct dma_slave_config cfg;
94 struct mtk_uart_apdma_desc *desc;
95 enum dma_transfer_direction dir;
100 unsigned int rx_status;
103 static inline struct mtk_uart_apdmadev *
104 to_mtk_uart_apdma_dev(struct dma_device *d)
106 return container_of(d, struct mtk_uart_apdmadev, ddev);
109 static inline struct mtk_chan *to_mtk_uart_apdma_chan(struct dma_chan *c)
111 return container_of(c, struct mtk_chan, vc.chan);
114 static inline struct mtk_uart_apdma_desc *to_mtk_uart_apdma_desc
115 (struct dma_async_tx_descriptor *t)
117 return container_of(t, struct mtk_uart_apdma_desc, vd.tx);
120 static void mtk_uart_apdma_write(struct mtk_chan *c,
121 unsigned int reg, unsigned int val)
123 writel(val, c->base + reg);
126 static unsigned int mtk_uart_apdma_read(struct mtk_chan *c, unsigned int reg)
128 return readl(c->base + reg);
131 static void mtk_uart_apdma_desc_free(struct virt_dma_desc *vd)
133 kfree(container_of(vd, struct mtk_uart_apdma_desc, vd));
136 static void mtk_uart_apdma_start_tx(struct mtk_chan *c)
138 struct mtk_uart_apdmadev *mtkd =
139 to_mtk_uart_apdma_dev(c->vc.chan.device);
140 struct mtk_uart_apdma_desc *d = c->desc;
141 unsigned int wpt, vff_sz;
143 vff_sz = c->cfg.dst_port_window_size;
144 if (!mtk_uart_apdma_read(c, VFF_LEN)) {
145 mtk_uart_apdma_write(c, VFF_ADDR, d->addr);
146 mtk_uart_apdma_write(c, VFF_LEN, vff_sz);
147 mtk_uart_apdma_write(c, VFF_THRE, VFF_TX_THRE(vff_sz));
148 mtk_uart_apdma_write(c, VFF_WPT, 0);
149 mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
151 if (mtkd->support_33bits)
152 mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_EN_B);
155 mtk_uart_apdma_write(c, VFF_EN, VFF_EN_B);
156 if (mtk_uart_apdma_read(c, VFF_EN) != VFF_EN_B)
157 dev_err(c->vc.chan.device->dev, "Enable TX fail\n");
159 if (!mtk_uart_apdma_read(c, VFF_LEFT_SIZE)) {
160 mtk_uart_apdma_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
164 wpt = mtk_uart_apdma_read(c, VFF_WPT);
166 wpt += c->desc->avail_len;
167 if ((wpt & VFF_RING_SIZE) == vff_sz)
168 wpt = (wpt & VFF_RING_WRAP) ^ VFF_RING_WRAP;
170 /* Let DMA start moving data */
171 mtk_uart_apdma_write(c, VFF_WPT, wpt);
173 /* HW auto set to 0 when left size >= threshold */
174 mtk_uart_apdma_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
175 if (!mtk_uart_apdma_read(c, VFF_FLUSH))
176 mtk_uart_apdma_write(c, VFF_FLUSH, VFF_FLUSH_B);
179 static void mtk_uart_apdma_start_rx(struct mtk_chan *c)
181 struct mtk_uart_apdmadev *mtkd =
182 to_mtk_uart_apdma_dev(c->vc.chan.device);
183 struct mtk_uart_apdma_desc *d = c->desc;
186 vff_sz = c->cfg.src_port_window_size;
187 if (!mtk_uart_apdma_read(c, VFF_LEN)) {
188 mtk_uart_apdma_write(c, VFF_ADDR, d->addr);
189 mtk_uart_apdma_write(c, VFF_LEN, vff_sz);
190 mtk_uart_apdma_write(c, VFF_THRE, VFF_RX_THRE(vff_sz));
191 mtk_uart_apdma_write(c, VFF_RPT, 0);
192 mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
194 if (mtkd->support_33bits)
195 mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_EN_B);
198 mtk_uart_apdma_write(c, VFF_INT_EN, VFF_RX_INT_EN_B);
199 mtk_uart_apdma_write(c, VFF_EN, VFF_EN_B);
200 if (mtk_uart_apdma_read(c, VFF_EN) != VFF_EN_B)
201 dev_err(c->vc.chan.device->dev, "Enable RX fail\n");
204 static void mtk_uart_apdma_tx_handler(struct mtk_chan *c)
206 mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
207 mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
208 mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
211 static void mtk_uart_apdma_rx_handler(struct mtk_chan *c)
213 struct mtk_uart_apdma_desc *d = c->desc;
214 unsigned int len, wg, rg;
217 mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
219 if (!mtk_uart_apdma_read(c, VFF_VALID_SIZE))
222 mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
223 mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
225 len = c->cfg.src_port_window_size;
226 rg = mtk_uart_apdma_read(c, VFF_RPT);
227 wg = mtk_uart_apdma_read(c, VFF_WPT);
228 cnt = (wg & VFF_RING_SIZE) - (rg & VFF_RING_SIZE);
231 * The buffer is ring buffer. If wrap bit different,
232 * represents the start of the next cycle for WPT
234 if ((rg ^ wg) & VFF_RING_WRAP)
237 c->rx_status = d->avail_len - cnt;
238 mtk_uart_apdma_write(c, VFF_RPT, wg);
241 static void mtk_uart_apdma_chan_complete_handler(struct mtk_chan *c)
243 struct mtk_uart_apdma_desc *d = c->desc;
246 list_del(&d->vd.node);
247 vchan_cookie_complete(&d->vd);
252 static irqreturn_t mtk_uart_apdma_irq_handler(int irq, void *dev_id)
254 struct dma_chan *chan = (struct dma_chan *)dev_id;
255 struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
258 spin_lock_irqsave(&c->vc.lock, flags);
259 if (c->dir == DMA_DEV_TO_MEM)
260 mtk_uart_apdma_rx_handler(c);
261 else if (c->dir == DMA_MEM_TO_DEV)
262 mtk_uart_apdma_tx_handler(c);
263 mtk_uart_apdma_chan_complete_handler(c);
264 spin_unlock_irqrestore(&c->vc.lock, flags);
269 static int mtk_uart_apdma_alloc_chan_resources(struct dma_chan *chan)
271 struct mtk_uart_apdmadev *mtkd = to_mtk_uart_apdma_dev(chan->device);
272 struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
276 ret = pm_runtime_resume_and_get(mtkd->ddev.dev);
278 pm_runtime_put_noidle(chan->device->dev);
282 mtk_uart_apdma_write(c, VFF_ADDR, 0);
283 mtk_uart_apdma_write(c, VFF_THRE, 0);
284 mtk_uart_apdma_write(c, VFF_LEN, 0);
285 mtk_uart_apdma_write(c, VFF_RST, VFF_WARM_RST_B);
287 ret = readx_poll_timeout(readl, c->base + VFF_EN,
288 status, !status, 10, 100);
292 ret = request_irq(c->irq, mtk_uart_apdma_irq_handler,
293 IRQF_TRIGGER_NONE, KBUILD_MODNAME, chan);
295 dev_err(chan->device->dev, "Can't request dma IRQ\n");
300 if (mtkd->support_33bits)
301 mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_CLR_B);
304 pm_runtime_put_noidle(mtkd->ddev.dev);
308 static void mtk_uart_apdma_free_chan_resources(struct dma_chan *chan)
310 struct mtk_uart_apdmadev *mtkd = to_mtk_uart_apdma_dev(chan->device);
311 struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
313 free_irq(c->irq, chan);
315 tasklet_kill(&c->vc.task);
317 vchan_free_chan_resources(&c->vc);
319 pm_runtime_put_sync(mtkd->ddev.dev);
322 static enum dma_status mtk_uart_apdma_tx_status(struct dma_chan *chan,
324 struct dma_tx_state *txstate)
326 struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
329 ret = dma_cookie_status(chan, cookie, txstate);
333 dma_set_residue(txstate, c->rx_status);
339 * dmaengine_prep_slave_single will call the function. and sglen is 1.
340 * 8250 uart using one ring buffer, and deal with one sg.
342 static struct dma_async_tx_descriptor *mtk_uart_apdma_prep_slave_sg
343 (struct dma_chan *chan, struct scatterlist *sgl,
344 unsigned int sglen, enum dma_transfer_direction dir,
345 unsigned long tx_flags, void *context)
347 struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
348 struct mtk_uart_apdma_desc *d;
350 if (!is_slave_direction(dir) || sglen != 1)
353 /* Now allocate and setup the descriptor */
354 d = kzalloc(sizeof(*d), GFP_NOWAIT);
358 d->avail_len = sg_dma_len(sgl);
359 d->addr = sg_dma_address(sgl);
362 return vchan_tx_prep(&c->vc, &d->vd, tx_flags);
365 static void mtk_uart_apdma_issue_pending(struct dma_chan *chan)
367 struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
368 struct virt_dma_desc *vd;
371 spin_lock_irqsave(&c->vc.lock, flags);
372 if (vchan_issue_pending(&c->vc) && !c->desc) {
373 vd = vchan_next_desc(&c->vc);
374 c->desc = to_mtk_uart_apdma_desc(&vd->tx);
376 if (c->dir == DMA_DEV_TO_MEM)
377 mtk_uart_apdma_start_rx(c);
378 else if (c->dir == DMA_MEM_TO_DEV)
379 mtk_uart_apdma_start_tx(c);
382 spin_unlock_irqrestore(&c->vc.lock, flags);
385 static int mtk_uart_apdma_slave_config(struct dma_chan *chan,
386 struct dma_slave_config *config)
388 struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
390 memcpy(&c->cfg, config, sizeof(*config));
395 static int mtk_uart_apdma_terminate_all(struct dma_chan *chan)
397 struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
403 mtk_uart_apdma_write(c, VFF_FLUSH, VFF_FLUSH_B);
405 ret = readx_poll_timeout(readl, c->base + VFF_FLUSH,
406 status, status != VFF_FLUSH_B, 10, 100);
408 dev_err(c->vc.chan.device->dev, "flush: fail, status=0x%x\n",
409 mtk_uart_apdma_read(c, VFF_DEBUG_STATUS));
417 mtk_uart_apdma_write(c, VFF_STOP, VFF_STOP_B);
418 ret = readx_poll_timeout(readl, c->base + VFF_EN,
419 status, !status, 10, 100);
421 dev_err(c->vc.chan.device->dev, "stop: fail, status=0x%x\n",
422 mtk_uart_apdma_read(c, VFF_DEBUG_STATUS));
424 mtk_uart_apdma_write(c, VFF_STOP, VFF_STOP_CLR_B);
425 mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
427 if (c->dir == DMA_DEV_TO_MEM)
428 mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
429 else if (c->dir == DMA_MEM_TO_DEV)
430 mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
432 synchronize_irq(c->irq);
434 spin_lock_irqsave(&c->vc.lock, flags);
435 vchan_get_all_descriptors(&c->vc, &head);
436 spin_unlock_irqrestore(&c->vc.lock, flags);
438 vchan_dma_desc_free_list(&c->vc, &head);
443 static int mtk_uart_apdma_device_pause(struct dma_chan *chan)
445 struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
448 spin_lock_irqsave(&c->vc.lock, flags);
450 mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
451 mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
453 spin_unlock_irqrestore(&c->vc.lock, flags);
454 synchronize_irq(c->irq);
459 static void mtk_uart_apdma_free(struct mtk_uart_apdmadev *mtkd)
461 while (!list_empty(&mtkd->ddev.channels)) {
462 struct mtk_chan *c = list_first_entry(&mtkd->ddev.channels,
463 struct mtk_chan, vc.chan.device_node);
465 list_del(&c->vc.chan.device_node);
466 tasklet_kill(&c->vc.task);
470 static const struct of_device_id mtk_uart_apdma_match[] = {
471 { .compatible = "mediatek,mt6577-uart-dma", },
474 MODULE_DEVICE_TABLE(of, mtk_uart_apdma_match);
476 static int mtk_uart_apdma_probe(struct platform_device *pdev)
478 struct device_node *np = pdev->dev.of_node;
479 struct mtk_uart_apdmadev *mtkd;
480 int bit_mask = 32, rc;
484 mtkd = devm_kzalloc(&pdev->dev, sizeof(*mtkd), GFP_KERNEL);
488 mtkd->clk = devm_clk_get(&pdev->dev, NULL);
489 if (IS_ERR(mtkd->clk)) {
490 dev_err(&pdev->dev, "No clock specified\n");
491 rc = PTR_ERR(mtkd->clk);
495 if (of_property_read_bool(np, "mediatek,dma-33bits"))
496 mtkd->support_33bits = true;
498 if (mtkd->support_33bits)
501 rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(bit_mask));
505 dma_cap_set(DMA_SLAVE, mtkd->ddev.cap_mask);
506 mtkd->ddev.device_alloc_chan_resources =
507 mtk_uart_apdma_alloc_chan_resources;
508 mtkd->ddev.device_free_chan_resources =
509 mtk_uart_apdma_free_chan_resources;
510 mtkd->ddev.device_tx_status = mtk_uart_apdma_tx_status;
511 mtkd->ddev.device_issue_pending = mtk_uart_apdma_issue_pending;
512 mtkd->ddev.device_prep_slave_sg = mtk_uart_apdma_prep_slave_sg;
513 mtkd->ddev.device_config = mtk_uart_apdma_slave_config;
514 mtkd->ddev.device_pause = mtk_uart_apdma_device_pause;
515 mtkd->ddev.device_terminate_all = mtk_uart_apdma_terminate_all;
516 mtkd->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
517 mtkd->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
518 mtkd->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
519 mtkd->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
520 mtkd->ddev.dev = &pdev->dev;
521 INIT_LIST_HEAD(&mtkd->ddev.channels);
523 mtkd->dma_requests = MTK_UART_APDMA_NR_VCHANS;
524 if (of_property_read_u32(np, "dma-requests", &mtkd->dma_requests)) {
526 "Using %u as missing dma-requests property\n",
527 MTK_UART_APDMA_NR_VCHANS);
530 for (i = 0; i < mtkd->dma_requests; i++) {
531 c = devm_kzalloc(mtkd->ddev.dev, sizeof(*c), GFP_KERNEL);
537 c->base = devm_platform_ioremap_resource(pdev, i);
538 if (IS_ERR(c->base)) {
539 rc = PTR_ERR(c->base);
542 c->vc.desc_free = mtk_uart_apdma_desc_free;
543 vchan_init(&c->vc, &mtkd->ddev);
545 rc = platform_get_irq(pdev, i);
551 pm_runtime_enable(&pdev->dev);
553 rc = dma_async_device_register(&mtkd->ddev);
557 platform_set_drvdata(pdev, mtkd);
559 /* Device-tree DMA controller registration */
560 rc = of_dma_controller_register(np, of_dma_xlate_by_chan_id, mtkd);
567 dma_async_device_unregister(&mtkd->ddev);
569 pm_runtime_disable(&pdev->dev);
571 mtk_uart_apdma_free(mtkd);
575 static int mtk_uart_apdma_remove(struct platform_device *pdev)
577 struct mtk_uart_apdmadev *mtkd = platform_get_drvdata(pdev);
579 of_dma_controller_free(pdev->dev.of_node);
581 mtk_uart_apdma_free(mtkd);
583 dma_async_device_unregister(&mtkd->ddev);
585 pm_runtime_disable(&pdev->dev);
590 #ifdef CONFIG_PM_SLEEP
591 static int mtk_uart_apdma_suspend(struct device *dev)
593 struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
595 if (!pm_runtime_suspended(dev))
596 clk_disable_unprepare(mtkd->clk);
601 static int mtk_uart_apdma_resume(struct device *dev)
604 struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
606 if (!pm_runtime_suspended(dev)) {
607 ret = clk_prepare_enable(mtkd->clk);
614 #endif /* CONFIG_PM_SLEEP */
617 static int mtk_uart_apdma_runtime_suspend(struct device *dev)
619 struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
621 clk_disable_unprepare(mtkd->clk);
626 static int mtk_uart_apdma_runtime_resume(struct device *dev)
628 struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
630 return clk_prepare_enable(mtkd->clk);
632 #endif /* CONFIG_PM */
634 static const struct dev_pm_ops mtk_uart_apdma_pm_ops = {
635 SET_SYSTEM_SLEEP_PM_OPS(mtk_uart_apdma_suspend, mtk_uart_apdma_resume)
636 SET_RUNTIME_PM_OPS(mtk_uart_apdma_runtime_suspend,
637 mtk_uart_apdma_runtime_resume, NULL)
640 static struct platform_driver mtk_uart_apdma_driver = {
641 .probe = mtk_uart_apdma_probe,
642 .remove = mtk_uart_apdma_remove,
644 .name = KBUILD_MODNAME,
645 .pm = &mtk_uart_apdma_pm_ops,
646 .of_match_table = of_match_ptr(mtk_uart_apdma_match),
650 module_platform_driver(mtk_uart_apdma_driver);
652 MODULE_DESCRIPTION("MediaTek UART APDMA Controller Driver");
653 MODULE_AUTHOR("Long Cheng <long.cheng@mediatek.com>");
654 MODULE_LICENSE("GPL v2");