xref: /openbmc/linux/drivers/remoteproc/mtk_scp.c (revision fb574682)
1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // Copyright (c) 2019 MediaTek Inc.
4 
5 #include <asm/barrier.h>
6 #include <linux/clk.h>
7 #include <linux/dma-mapping.h>
8 #include <linux/err.h>
9 #include <linux/interrupt.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/of_address.h>
13 #include <linux/of_platform.h>
14 #include <linux/of_reserved_mem.h>
15 #include <linux/platform_device.h>
16 #include <linux/remoteproc.h>
17 #include <linux/remoteproc/mtk_scp.h>
18 #include <linux/rpmsg/mtk_rpmsg.h>
19 
20 #include "mtk_common.h"
21 #include "remoteproc_internal.h"
22 
23 #define MAX_CODE_SIZE 0x500000
24 #define SCP_FW_END 0x7C000
25 
26 /**
27  * scp_get() - get a reference to SCP.
28  *
29  * @pdev:	the platform device of the module requesting SCP platform
30  *		device for using SCP API.
31  *
32  * Return: Return NULL if failed.  otherwise reference to SCP.
33  **/
34 struct mtk_scp *scp_get(struct platform_device *pdev)
35 {
36 	struct device *dev = &pdev->dev;
37 	struct device_node *scp_node;
38 	struct platform_device *scp_pdev;
39 
40 	scp_node = of_parse_phandle(dev->of_node, "mediatek,scp", 0);
41 	if (!scp_node) {
42 		dev_err(dev, "can't get SCP node\n");
43 		return NULL;
44 	}
45 
46 	scp_pdev = of_find_device_by_node(scp_node);
47 	of_node_put(scp_node);
48 
49 	if (WARN_ON(!scp_pdev)) {
50 		dev_err(dev, "SCP pdev failed\n");
51 		return NULL;
52 	}
53 
54 	return platform_get_drvdata(scp_pdev);
55 }
56 EXPORT_SYMBOL_GPL(scp_get);
57 
58 /**
59  * scp_put() - "free" the SCP
60  *
61  * @scp:	mtk_scp structure from scp_get().
62  **/
63 void scp_put(struct mtk_scp *scp)
64 {
65 	put_device(scp->dev);
66 }
67 EXPORT_SYMBOL_GPL(scp_put);
68 
69 static void scp_wdt_handler(struct mtk_scp *scp, u32 scp_to_host)
70 {
71 	dev_err(scp->dev, "SCP watchdog timeout! 0x%x", scp_to_host);
72 	rproc_report_crash(scp->rproc, RPROC_WATCHDOG);
73 }
74 
75 static void scp_init_ipi_handler(void *data, unsigned int len, void *priv)
76 {
77 	struct mtk_scp *scp = (struct mtk_scp *)priv;
78 	struct scp_run *run = (struct scp_run *)data;
79 
80 	scp->run.signaled = run->signaled;
81 	strscpy(scp->run.fw_ver, run->fw_ver, SCP_FW_VER_LEN);
82 	scp->run.dec_capability = run->dec_capability;
83 	scp->run.enc_capability = run->enc_capability;
84 	wake_up_interruptible(&scp->run.wq);
85 }
86 
87 static void scp_ipi_handler(struct mtk_scp *scp)
88 {
89 	struct mtk_share_obj __iomem *rcv_obj = scp->recv_buf;
90 	struct scp_ipi_desc *ipi_desc = scp->ipi_desc;
91 	u8 tmp_data[SCP_SHARE_BUFFER_SIZE];
92 	scp_ipi_handler_t handler;
93 	u32 id = readl(&rcv_obj->id);
94 	u32 len = readl(&rcv_obj->len);
95 
96 	if (len > SCP_SHARE_BUFFER_SIZE) {
97 		dev_err(scp->dev, "ipi message too long (len %d, max %d)", len,
98 			SCP_SHARE_BUFFER_SIZE);
99 		return;
100 	}
101 	if (id >= SCP_IPI_MAX) {
102 		dev_err(scp->dev, "No such ipi id = %d\n", id);
103 		return;
104 	}
105 
106 	scp_ipi_lock(scp, id);
107 	handler = ipi_desc[id].handler;
108 	if (!handler) {
109 		dev_err(scp->dev, "No such ipi id = %d\n", id);
110 		scp_ipi_unlock(scp, id);
111 		return;
112 	}
113 
114 	memcpy_fromio(tmp_data, &rcv_obj->share_buf, len);
115 	handler(tmp_data, len, ipi_desc[id].priv);
116 	scp_ipi_unlock(scp, id);
117 
118 	scp->ipi_id_ack[id] = true;
119 	wake_up(&scp->ack_wq);
120 }
121 
122 static int scp_ipi_init(struct mtk_scp *scp)
123 {
124 	size_t send_offset = SCP_FW_END - sizeof(struct mtk_share_obj);
125 	size_t recv_offset = send_offset - sizeof(struct mtk_share_obj);
126 
127 	/* Disable SCP to host interrupt */
128 	writel(MT8183_SCP_IPC_INT_BIT, scp->reg_base + MT8183_SCP_TO_HOST);
129 
130 	/* shared buffer initialization */
131 	scp->recv_buf =
132 		(struct mtk_share_obj __iomem *)(scp->sram_base + recv_offset);
133 	scp->send_buf =
134 		(struct mtk_share_obj __iomem *)(scp->sram_base + send_offset);
135 	memset_io(scp->recv_buf, 0, sizeof(*scp->recv_buf));
136 	memset_io(scp->send_buf, 0, sizeof(*scp->send_buf));
137 
138 	return 0;
139 }
140 
141 static void scp_reset_assert(const struct mtk_scp *scp)
142 {
143 	u32 val;
144 
145 	val = readl(scp->reg_base + MT8183_SW_RSTN);
146 	val &= ~MT8183_SW_RSTN_BIT;
147 	writel(val, scp->reg_base + MT8183_SW_RSTN);
148 }
149 
150 static void scp_reset_deassert(const struct mtk_scp *scp)
151 {
152 	u32 val;
153 
154 	val = readl(scp->reg_base + MT8183_SW_RSTN);
155 	val |= MT8183_SW_RSTN_BIT;
156 	writel(val, scp->reg_base + MT8183_SW_RSTN);
157 }
158 
159 static irqreturn_t scp_irq_handler(int irq, void *priv)
160 {
161 	struct mtk_scp *scp = priv;
162 	u32 scp_to_host;
163 	int ret;
164 
165 	ret = clk_prepare_enable(scp->clk);
166 	if (ret) {
167 		dev_err(scp->dev, "failed to enable clocks\n");
168 		return IRQ_NONE;
169 	}
170 
171 	scp_to_host = readl(scp->reg_base + MT8183_SCP_TO_HOST);
172 	if (scp_to_host & MT8183_SCP_IPC_INT_BIT)
173 		scp_ipi_handler(scp);
174 	else
175 		scp_wdt_handler(scp, scp_to_host);
176 
177 	/* SCP won't send another interrupt until we set SCP_TO_HOST to 0. */
178 	writel(MT8183_SCP_IPC_INT_BIT | MT8183_SCP_WDT_INT_BIT,
179 	       scp->reg_base + MT8183_SCP_TO_HOST);
180 	clk_disable_unprepare(scp->clk);
181 
182 	return IRQ_HANDLED;
183 }
184 
185 static int scp_elf_load_segments(struct rproc *rproc, const struct firmware *fw)
186 {
187 	struct device *dev = &rproc->dev;
188 	struct elf32_hdr *ehdr;
189 	struct elf32_phdr *phdr;
190 	int i, ret = 0;
191 	const u8 *elf_data = fw->data;
192 
193 	ehdr = (struct elf32_hdr *)elf_data;
194 	phdr = (struct elf32_phdr *)(elf_data + ehdr->e_phoff);
195 
196 	/* go through the available ELF segments */
197 	for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
198 		u32 da = phdr->p_paddr;
199 		u32 memsz = phdr->p_memsz;
200 		u32 filesz = phdr->p_filesz;
201 		u32 offset = phdr->p_offset;
202 		void __iomem *ptr;
203 
204 		if (phdr->p_type != PT_LOAD)
205 			continue;
206 
207 		dev_dbg(dev, "phdr: type %d da 0x%x memsz 0x%x filesz 0x%x\n",
208 			phdr->p_type, da, memsz, filesz);
209 
210 		if (filesz > memsz) {
211 			dev_err(dev, "bad phdr filesz 0x%x memsz 0x%x\n",
212 				filesz, memsz);
213 			ret = -EINVAL;
214 			break;
215 		}
216 
217 		if (offset + filesz > fw->size) {
218 			dev_err(dev, "truncated fw: need 0x%x avail 0x%zx\n",
219 				offset + filesz, fw->size);
220 			ret = -EINVAL;
221 			break;
222 		}
223 
224 		/* grab the kernel address for this device address */
225 		ptr = (void __iomem *)rproc_da_to_va(rproc, da, memsz);
226 		if (!ptr) {
227 			dev_err(dev, "bad phdr da 0x%x mem 0x%x\n", da, memsz);
228 			ret = -EINVAL;
229 			break;
230 		}
231 
232 		/* put the segment where the remote processor expects it */
233 		if (phdr->p_filesz)
234 			scp_memcpy_aligned(ptr, elf_data + phdr->p_offset,
235 					   filesz);
236 	}
237 
238 	return ret;
239 }
240 
241 static int scp_load(struct rproc *rproc, const struct firmware *fw)
242 {
243 	const struct mtk_scp *scp = rproc->priv;
244 	struct device *dev = scp->dev;
245 	int ret;
246 
247 	ret = clk_prepare_enable(scp->clk);
248 	if (ret) {
249 		dev_err(dev, "failed to enable clocks\n");
250 		return ret;
251 	}
252 
253 	/* Hold SCP in reset while loading FW. */
254 	scp_reset_assert(scp);
255 
256 	/* Reset clocks before loading FW */
257 	writel(0x0, scp->reg_base + MT8183_SCP_CLK_SW_SEL);
258 	writel(0x0, scp->reg_base + MT8183_SCP_CLK_DIV_SEL);
259 
260 	/* Initialize TCM before loading FW. */
261 	writel(0x0, scp->reg_base + MT8183_SCP_L1_SRAM_PD);
262 	writel(0x0, scp->reg_base + MT8183_SCP_TCM_TAIL_SRAM_PD);
263 
264 	/* Turn on the power of SCP's SRAM before using it. */
265 	writel(0x0, scp->reg_base + MT8183_SCP_SRAM_PDN);
266 
267 	/*
268 	 * Set I-cache and D-cache size before loading SCP FW.
269 	 * SCP SRAM logical address may change when cache size setting differs.
270 	 */
271 	writel(MT8183_SCP_CACHE_CON_WAYEN | MT8183_SCP_CACHESIZE_8KB,
272 	       scp->reg_base + MT8183_SCP_CACHE_CON);
273 	writel(MT8183_SCP_CACHESIZE_8KB, scp->reg_base + MT8183_SCP_DCACHE_CON);
274 
275 	ret = scp_elf_load_segments(rproc, fw);
276 	clk_disable_unprepare(scp->clk);
277 
278 	return ret;
279 }
280 
281 static int scp_start(struct rproc *rproc)
282 {
283 	struct mtk_scp *scp = (struct mtk_scp *)rproc->priv;
284 	struct device *dev = scp->dev;
285 	struct scp_run *run = &scp->run;
286 	int ret;
287 
288 	ret = clk_prepare_enable(scp->clk);
289 	if (ret) {
290 		dev_err(dev, "failed to enable clocks\n");
291 		return ret;
292 	}
293 
294 	run->signaled = false;
295 
296 	scp_reset_deassert(scp);
297 
298 	ret = wait_event_interruptible_timeout(
299 					run->wq,
300 					run->signaled,
301 					msecs_to_jiffies(2000));
302 
303 	if (ret == 0) {
304 		dev_err(dev, "wait SCP initialization timeout!\n");
305 		ret = -ETIME;
306 		goto stop;
307 	}
308 	if (ret == -ERESTARTSYS) {
309 		dev_err(dev, "wait SCP interrupted by a signal!\n");
310 		goto stop;
311 	}
312 	clk_disable_unprepare(scp->clk);
313 	dev_info(dev, "SCP is ready. FW version %s\n", run->fw_ver);
314 
315 	return 0;
316 
317 stop:
318 	scp_reset_assert(scp);
319 	clk_disable_unprepare(scp->clk);
320 	return ret;
321 }
322 
323 static void *scp_da_to_va(struct rproc *rproc, u64 da, size_t len)
324 {
325 	struct mtk_scp *scp = (struct mtk_scp *)rproc->priv;
326 	int offset;
327 
328 	if (da < scp->sram_size) {
329 		offset = da;
330 		if (offset >= 0 && (offset + len) < scp->sram_size)
331 			return (void __force *)scp->sram_base + offset;
332 	} else {
333 		offset = da - scp->dma_addr;
334 		if (offset >= 0 && (offset + len) < scp->dram_size)
335 			return (void __force *)scp->cpu_addr + offset;
336 	}
337 
338 	return NULL;
339 }
340 
341 static int scp_stop(struct rproc *rproc)
342 {
343 	struct mtk_scp *scp = (struct mtk_scp *)rproc->priv;
344 	int ret;
345 
346 	ret = clk_prepare_enable(scp->clk);
347 	if (ret) {
348 		dev_err(scp->dev, "failed to enable clocks\n");
349 		return ret;
350 	}
351 
352 	scp_reset_assert(scp);
353 	/* Disable SCP watchdog */
354 	writel(0, scp->reg_base + MT8183_WDT_CFG);
355 	clk_disable_unprepare(scp->clk);
356 
357 	return 0;
358 }
359 
360 static const struct rproc_ops scp_ops = {
361 	.start		= scp_start,
362 	.stop		= scp_stop,
363 	.load		= scp_load,
364 	.da_to_va	= scp_da_to_va,
365 };
366 
367 /**
368  * scp_get_device() - get device struct of SCP
369  *
370  * @scp:	mtk_scp structure
371  **/
372 struct device *scp_get_device(struct mtk_scp *scp)
373 {
374 	return scp->dev;
375 }
376 EXPORT_SYMBOL_GPL(scp_get_device);
377 
378 /**
379  * scp_get_rproc() - get rproc struct of SCP
380  *
381  * @scp:	mtk_scp structure
382  **/
383 struct rproc *scp_get_rproc(struct mtk_scp *scp)
384 {
385 	return scp->rproc;
386 }
387 EXPORT_SYMBOL_GPL(scp_get_rproc);
388 
389 /**
390  * scp_get_vdec_hw_capa() - get video decoder hardware capability
391  *
392  * @scp:	mtk_scp structure
393  *
394  * Return: video decoder hardware capability
395  **/
396 unsigned int scp_get_vdec_hw_capa(struct mtk_scp *scp)
397 {
398 	return scp->run.dec_capability;
399 }
400 EXPORT_SYMBOL_GPL(scp_get_vdec_hw_capa);
401 
402 /**
403  * scp_get_venc_hw_capa() - get video encoder hardware capability
404  *
405  * @scp:	mtk_scp structure
406  *
407  * Return: video encoder hardware capability
408  **/
409 unsigned int scp_get_venc_hw_capa(struct mtk_scp *scp)
410 {
411 	return scp->run.enc_capability;
412 }
413 EXPORT_SYMBOL_GPL(scp_get_venc_hw_capa);
414 
415 /**
416  * scp_mapping_dm_addr() - Mapping SRAM/DRAM to kernel virtual address
417  *
418  * @scp:	mtk_scp structure
419  * @mem_addr:	SCP views memory address
420  *
421  * Mapping the SCP's SRAM address /
422  * DMEM (Data Extended Memory) memory address /
423  * Working buffer memory address to
424  * kernel virtual address.
425  *
426  * Return: Return ERR_PTR(-EINVAL) if mapping failed,
427  * otherwise the mapped kernel virtual address
428  **/
429 void *scp_mapping_dm_addr(struct mtk_scp *scp, u32 mem_addr)
430 {
431 	void *ptr;
432 
433 	ptr = scp_da_to_va(scp->rproc, mem_addr, 0);
434 	if (!ptr)
435 		return ERR_PTR(-EINVAL);
436 
437 	return ptr;
438 }
439 EXPORT_SYMBOL_GPL(scp_mapping_dm_addr);
440 
441 static int scp_map_memory_region(struct mtk_scp *scp)
442 {
443 	int ret;
444 
445 	ret = of_reserved_mem_device_init(scp->dev);
446 	if (ret) {
447 		dev_err(scp->dev, "failed to assign memory-region: %d\n", ret);
448 		return -ENOMEM;
449 	}
450 
451 	/* Reserved SCP code size */
452 	scp->dram_size = MAX_CODE_SIZE;
453 	scp->cpu_addr = dma_alloc_coherent(scp->dev, scp->dram_size,
454 					   &scp->dma_addr, GFP_KERNEL);
455 	if (!scp->cpu_addr)
456 		return -ENOMEM;
457 
458 	return 0;
459 }
460 
461 static void scp_unmap_memory_region(struct mtk_scp *scp)
462 {
463 	dma_free_coherent(scp->dev, scp->dram_size, scp->cpu_addr,
464 			  scp->dma_addr);
465 	of_reserved_mem_device_release(scp->dev);
466 }
467 
468 static int scp_register_ipi(struct platform_device *pdev, u32 id,
469 			    ipi_handler_t handler, void *priv)
470 {
471 	struct mtk_scp *scp = platform_get_drvdata(pdev);
472 
473 	return scp_ipi_register(scp, id, handler, priv);
474 }
475 
476 static void scp_unregister_ipi(struct platform_device *pdev, u32 id)
477 {
478 	struct mtk_scp *scp = platform_get_drvdata(pdev);
479 
480 	scp_ipi_unregister(scp, id);
481 }
482 
483 static int scp_send_ipi(struct platform_device *pdev, u32 id, void *buf,
484 			unsigned int len, unsigned int wait)
485 {
486 	struct mtk_scp *scp = platform_get_drvdata(pdev);
487 
488 	return scp_ipi_send(scp, id, buf, len, wait);
489 }
490 
491 static struct mtk_rpmsg_info mtk_scp_rpmsg_info = {
492 	.send_ipi = scp_send_ipi,
493 	.register_ipi = scp_register_ipi,
494 	.unregister_ipi = scp_unregister_ipi,
495 	.ns_ipi_id = SCP_IPI_NS_SERVICE,
496 };
497 
498 static void scp_add_rpmsg_subdev(struct mtk_scp *scp)
499 {
500 	scp->rpmsg_subdev =
501 		mtk_rpmsg_create_rproc_subdev(to_platform_device(scp->dev),
502 					      &mtk_scp_rpmsg_info);
503 	if (scp->rpmsg_subdev)
504 		rproc_add_subdev(scp->rproc, scp->rpmsg_subdev);
505 }
506 
507 static void scp_remove_rpmsg_subdev(struct mtk_scp *scp)
508 {
509 	if (scp->rpmsg_subdev) {
510 		rproc_remove_subdev(scp->rproc, scp->rpmsg_subdev);
511 		mtk_rpmsg_destroy_rproc_subdev(scp->rpmsg_subdev);
512 		scp->rpmsg_subdev = NULL;
513 	}
514 }
515 
516 static int scp_probe(struct platform_device *pdev)
517 {
518 	struct device *dev = &pdev->dev;
519 	struct device_node *np = dev->of_node;
520 	struct mtk_scp *scp;
521 	struct rproc *rproc;
522 	struct resource *res;
523 	char *fw_name = "scp.img";
524 	int ret, i;
525 
526 	rproc = rproc_alloc(dev,
527 			    np->name,
528 			    &scp_ops,
529 			    fw_name,
530 			    sizeof(*scp));
531 	if (!rproc) {
532 		dev_err(dev, "unable to allocate remoteproc\n");
533 		return -ENOMEM;
534 	}
535 
536 	scp = (struct mtk_scp *)rproc->priv;
537 	scp->rproc = rproc;
538 	scp->dev = dev;
539 	platform_set_drvdata(pdev, scp);
540 
541 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "sram");
542 	scp->sram_base = devm_ioremap_resource(dev, res);
543 	if (IS_ERR((__force void *)scp->sram_base)) {
544 		dev_err(dev, "Failed to parse and map sram memory\n");
545 		ret = PTR_ERR((__force void *)scp->sram_base);
546 		goto free_rproc;
547 	}
548 	scp->sram_size = resource_size(res);
549 
550 	mutex_init(&scp->send_lock);
551 	for (i = 0; i < SCP_IPI_MAX; i++)
552 		mutex_init(&scp->ipi_desc[i].lock);
553 
554 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
555 	scp->reg_base = devm_ioremap_resource(dev, res);
556 	if (IS_ERR((__force void *)scp->reg_base)) {
557 		dev_err(dev, "Failed to parse and map cfg memory\n");
558 		ret = PTR_ERR((__force void *)scp->reg_base);
559 		goto destroy_mutex;
560 	}
561 
562 	ret = scp_map_memory_region(scp);
563 	if (ret)
564 		goto destroy_mutex;
565 
566 	scp->clk = devm_clk_get(dev, "main");
567 	if (IS_ERR(scp->clk)) {
568 		dev_err(dev, "Failed to get clock\n");
569 		ret = PTR_ERR(scp->clk);
570 		goto release_dev_mem;
571 	}
572 
573 	ret = clk_prepare_enable(scp->clk);
574 	if (ret) {
575 		dev_err(dev, "failed to enable clocks\n");
576 		goto release_dev_mem;
577 	}
578 
579 	ret = scp_ipi_init(scp);
580 	clk_disable_unprepare(scp->clk);
581 	if (ret) {
582 		dev_err(dev, "Failed to init ipi\n");
583 		goto release_dev_mem;
584 	}
585 
586 	/* register SCP initialization IPI */
587 	ret = scp_ipi_register(scp, SCP_IPI_INIT, scp_init_ipi_handler, scp);
588 	if (ret) {
589 		dev_err(dev, "Failed to register IPI_SCP_INIT\n");
590 		goto release_dev_mem;
591 	}
592 
593 	init_waitqueue_head(&scp->run.wq);
594 	init_waitqueue_head(&scp->ack_wq);
595 
596 	scp_add_rpmsg_subdev(scp);
597 
598 	ret = devm_request_threaded_irq(dev, platform_get_irq(pdev, 0), NULL,
599 					scp_irq_handler, IRQF_ONESHOT,
600 					pdev->name, scp);
601 
602 	if (ret) {
603 		dev_err(dev, "failed to request irq\n");
604 		goto remove_subdev;
605 	}
606 
607 	ret = rproc_add(rproc);
608 	if (ret)
609 		goto remove_subdev;
610 
611 	return 0;
612 
613 remove_subdev:
614 	scp_remove_rpmsg_subdev(scp);
615 	scp_ipi_unregister(scp, SCP_IPI_INIT);
616 release_dev_mem:
617 	scp_unmap_memory_region(scp);
618 destroy_mutex:
619 	for (i = 0; i < SCP_IPI_MAX; i++)
620 		mutex_destroy(&scp->ipi_desc[i].lock);
621 	mutex_destroy(&scp->send_lock);
622 free_rproc:
623 	rproc_free(rproc);
624 
625 	return ret;
626 }
627 
628 static int scp_remove(struct platform_device *pdev)
629 {
630 	struct mtk_scp *scp = platform_get_drvdata(pdev);
631 	int i;
632 
633 	rproc_del(scp->rproc);
634 	scp_remove_rpmsg_subdev(scp);
635 	scp_ipi_unregister(scp, SCP_IPI_INIT);
636 	scp_unmap_memory_region(scp);
637 	for (i = 0; i < SCP_IPI_MAX; i++)
638 		mutex_destroy(&scp->ipi_desc[i].lock);
639 	mutex_destroy(&scp->send_lock);
640 	rproc_free(scp->rproc);
641 
642 	return 0;
643 }
644 
645 static const struct of_device_id mtk_scp_of_match[] = {
646 	{ .compatible = "mediatek,mt8183-scp"},
647 	{},
648 };
649 MODULE_DEVICE_TABLE(of, mtk_scp_of_match);
650 
651 static struct platform_driver mtk_scp_driver = {
652 	.probe = scp_probe,
653 	.remove = scp_remove,
654 	.driver = {
655 		.name = "mtk-scp",
656 		.of_match_table = of_match_ptr(mtk_scp_of_match),
657 	},
658 };
659 
660 module_platform_driver(mtk_scp_driver);
661 
662 MODULE_LICENSE("GPL v2");
663 MODULE_DESCRIPTION("MediaTek SCP control driver");
664