1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * aspeed-vhub -- Driver for Aspeed SoC "vHub" USB gadget
4  *
5  * core.c - Top level support
6  *
7  * Copyright 2017 IBM Corporation
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  */
14 
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/platform_device.h>
18 #include <linux/delay.h>
19 #include <linux/ioport.h>
20 #include <linux/slab.h>
21 #include <linux/errno.h>
22 #include <linux/list.h>
23 #include <linux/interrupt.h>
24 #include <linux/proc_fs.h>
25 #include <linux/prefetch.h>
26 #include <linux/clk.h>
27 #include <linux/usb/gadget.h>
28 #include <linux/of.h>
29 #include <linux/of_gpio.h>
30 #include <linux/regmap.h>
31 #include <linux/dma-mapping.h>
32 
33 #include "vhub.h"
34 
35 void ast_vhub_done(struct ast_vhub_ep *ep, struct ast_vhub_req *req,
36 		   int status)
37 {
38 	bool internal = req->internal;
39 	struct ast_vhub *vhub = ep->vhub;
40 
41 	EPVDBG(ep, "completing request @%p, status %d\n", req, status);
42 
43 	list_del_init(&req->queue);
44 
45 	if (req->req.status == -EINPROGRESS)
46 		req->req.status = status;
47 
48 	if (req->req.dma) {
49 		if (!WARN_ON(!ep->dev))
50 			usb_gadget_unmap_request_by_dev(&vhub->pdev->dev,
51 						 &req->req, ep->epn.is_in);
52 		req->req.dma = 0;
53 	}
54 
55 	/*
56 	 * If this isn't an internal EP0 request, call the core
57 	 * to call the gadget completion.
58 	 */
59 	if (!internal) {
60 		spin_unlock(&ep->vhub->lock);
61 		usb_gadget_giveback_request(&ep->ep, &req->req);
62 		spin_lock(&ep->vhub->lock);
63 	}
64 }
65 
66 void ast_vhub_nuke(struct ast_vhub_ep *ep, int status)
67 {
68 	struct ast_vhub_req *req;
69 	int count = 0;
70 
71 	/* Beware, lock will be dropped & req-acquired by done() */
72 	while (!list_empty(&ep->queue)) {
73 		req = list_first_entry(&ep->queue, struct ast_vhub_req, queue);
74 		ast_vhub_done(ep, req, status);
75 		count++;
76 	}
77 	if (count)
78 		EPDBG(ep, "Nuked %d request(s)\n", count);
79 }
80 
81 struct usb_request *ast_vhub_alloc_request(struct usb_ep *u_ep,
82 					   gfp_t gfp_flags)
83 {
84 	struct ast_vhub_req *req;
85 
86 	req = kzalloc(sizeof(*req), gfp_flags);
87 	if (!req)
88 		return NULL;
89 	return &req->req;
90 }
91 
92 void ast_vhub_free_request(struct usb_ep *u_ep, struct usb_request *u_req)
93 {
94 	struct ast_vhub_req *req = to_ast_req(u_req);
95 
96 	kfree(req);
97 }
98 
99 static irqreturn_t ast_vhub_irq(int irq, void *data)
100 {
101 	struct ast_vhub *vhub = data;
102 	irqreturn_t iret = IRQ_NONE;
103 	u32 i, istat;
104 
105 	/* Stale interrupt while tearing down */
106 	if (!vhub->ep0_bufs)
107 		return IRQ_NONE;
108 
109 	spin_lock(&vhub->lock);
110 
111 	/* Read and ACK interrupts */
112 	istat = readl(vhub->regs + AST_VHUB_ISR);
113 	if (!istat)
114 		goto bail;
115 	writel(istat, vhub->regs + AST_VHUB_ISR);
116 	iret = IRQ_HANDLED;
117 
118 	UDCVDBG(vhub, "irq status=%08x, ep_acks=%08x ep_nacks=%08x\n",
119 	       istat,
120 	       readl(vhub->regs + AST_VHUB_EP_ACK_ISR),
121 	       readl(vhub->regs + AST_VHUB_EP_NACK_ISR));
122 
123 	/* Handle generic EPs first */
124 	if (istat & VHUB_IRQ_EP_POOL_ACK_STALL) {
125 		u32 ep_acks = readl(vhub->regs + AST_VHUB_EP_ACK_ISR);
126 		writel(ep_acks, vhub->regs + AST_VHUB_EP_ACK_ISR);
127 
128 		for (i = 0; ep_acks && i < vhub->max_epns; i++) {
129 			u32 mask = VHUB_EP_IRQ(i);
130 			if (ep_acks & mask) {
131 				ast_vhub_epn_ack_irq(&vhub->epns[i]);
132 				ep_acks &= ~mask;
133 			}
134 		}
135 	}
136 
137 	/* Handle device interrupts */
138 	if (istat & vhub->port_irq_mask) {
139 		for (i = 0; i < vhub->max_ports; i++) {
140 			if (istat & VHUB_DEV_IRQ(i))
141 				ast_vhub_dev_irq(&vhub->ports[i].dev);
142 		}
143 	}
144 
145 	/* Handle top-level vHub EP0 interrupts */
146 	if (istat & (VHUB_IRQ_HUB_EP0_OUT_ACK_STALL |
147 		     VHUB_IRQ_HUB_EP0_IN_ACK_STALL |
148 		     VHUB_IRQ_HUB_EP0_SETUP)) {
149 		if (istat & VHUB_IRQ_HUB_EP0_IN_ACK_STALL)
150 			ast_vhub_ep0_handle_ack(&vhub->ep0, true);
151 		if (istat & VHUB_IRQ_HUB_EP0_OUT_ACK_STALL)
152 			ast_vhub_ep0_handle_ack(&vhub->ep0, false);
153 		if (istat & VHUB_IRQ_HUB_EP0_SETUP)
154 			ast_vhub_ep0_handle_setup(&vhub->ep0);
155 	}
156 
157 	/* Various top level bus events */
158 	if (istat & (VHUB_IRQ_BUS_RESUME |
159 		     VHUB_IRQ_BUS_SUSPEND |
160 		     VHUB_IRQ_BUS_RESET)) {
161 		if (istat & VHUB_IRQ_BUS_RESUME)
162 			ast_vhub_hub_resume(vhub);
163 		if (istat & VHUB_IRQ_BUS_SUSPEND)
164 			ast_vhub_hub_suspend(vhub);
165 		if (istat & VHUB_IRQ_BUS_RESET)
166 			ast_vhub_hub_reset(vhub);
167 	}
168 
169  bail:
170 	spin_unlock(&vhub->lock);
171 	return iret;
172 }
173 
174 void ast_vhub_init_hw(struct ast_vhub *vhub)
175 {
176 	u32 ctrl, port_mask, epn_mask;
177 
178 	UDCDBG(vhub,"(Re)Starting HW ...\n");
179 
180 	/* Enable PHY */
181 	ctrl = VHUB_CTRL_PHY_CLK |
182 		VHUB_CTRL_PHY_RESET_DIS;
183 
184        /*
185 	* We do *NOT* set the VHUB_CTRL_CLK_STOP_SUSPEND bit
186 	* to stop the logic clock during suspend because
187 	* it causes the registers to become inaccessible and
188 	* we haven't yet figured out a good wayt to bring the
189 	* controller back into life to issue a wakeup.
190 	*/
191 
192 	/*
193 	 * Set some ISO & split control bits according to Aspeed
194 	 * recommendation
195 	 *
196 	 * VHUB_CTRL_ISO_RSP_CTRL: When set tells the HW to respond
197 	 * with 0 bytes data packet to ISO IN endpoints when no data
198 	 * is available.
199 	 *
200 	 * VHUB_CTRL_SPLIT_IN: This makes a SOF complete a split IN
201 	 * transaction.
202 	 */
203 	ctrl |= VHUB_CTRL_ISO_RSP_CTRL | VHUB_CTRL_SPLIT_IN;
204 	writel(ctrl, vhub->regs + AST_VHUB_CTRL);
205 	udelay(1);
206 
207 	/* Set descriptor ring size */
208 	if (AST_VHUB_DESCS_COUNT == 256) {
209 		ctrl |= VHUB_CTRL_LONG_DESC;
210 		writel(ctrl, vhub->regs + AST_VHUB_CTRL);
211 	} else {
212 		BUILD_BUG_ON(AST_VHUB_DESCS_COUNT != 32);
213 	}
214 
215 	/* Reset all devices */
216 	port_mask = GENMASK(vhub->max_ports, 1);
217 	writel(VHUB_SW_RESET_ROOT_HUB |
218 	       VHUB_SW_RESET_DMA_CONTROLLER |
219 	       VHUB_SW_RESET_EP_POOL |
220 	       port_mask, vhub->regs + AST_VHUB_SW_RESET);
221 	udelay(1);
222 	writel(0, vhub->regs + AST_VHUB_SW_RESET);
223 
224 	/* Disable and cleanup EP ACK/NACK interrupts */
225 	epn_mask = GENMASK(vhub->max_epns - 1, 0);
226 	writel(0, vhub->regs + AST_VHUB_EP_ACK_IER);
227 	writel(0, vhub->regs + AST_VHUB_EP_NACK_IER);
228 	writel(epn_mask, vhub->regs + AST_VHUB_EP_ACK_ISR);
229 	writel(epn_mask, vhub->regs + AST_VHUB_EP_NACK_ISR);
230 
231 	/* Default settings for EP0, enable HW hub EP1 */
232 	writel(0, vhub->regs + AST_VHUB_EP0_CTRL);
233 	writel(VHUB_EP1_CTRL_RESET_TOGGLE |
234 	       VHUB_EP1_CTRL_ENABLE,
235 	       vhub->regs + AST_VHUB_EP1_CTRL);
236 	writel(0, vhub->regs + AST_VHUB_EP1_STS_CHG);
237 
238 	/* Configure EP0 DMA buffer */
239 	writel(vhub->ep0.buf_dma, vhub->regs + AST_VHUB_EP0_DATA);
240 
241 	/* Clear address */
242 	writel(0, vhub->regs + AST_VHUB_CONF);
243 
244 	/* Pullup hub (activate on host) */
245 	if (vhub->force_usb1)
246 		ctrl |= VHUB_CTRL_FULL_SPEED_ONLY;
247 
248 	ctrl |= VHUB_CTRL_UPSTREAM_CONNECT;
249 	writel(ctrl, vhub->regs + AST_VHUB_CTRL);
250 
251 	/* Enable some interrupts */
252 	writel(VHUB_IRQ_HUB_EP0_IN_ACK_STALL |
253 	       VHUB_IRQ_HUB_EP0_OUT_ACK_STALL |
254 	       VHUB_IRQ_HUB_EP0_SETUP |
255 	       VHUB_IRQ_EP_POOL_ACK_STALL |
256 	       VHUB_IRQ_BUS_RESUME |
257 	       VHUB_IRQ_BUS_SUSPEND |
258 	       VHUB_IRQ_BUS_RESET,
259 	       vhub->regs + AST_VHUB_IER);
260 }
261 
262 static int ast_vhub_remove(struct platform_device *pdev)
263 {
264 	struct ast_vhub *vhub = platform_get_drvdata(pdev);
265 	unsigned long flags;
266 	int i;
267 
268 	if (!vhub || !vhub->regs)
269 		return 0;
270 
271 	/* Remove devices */
272 	for (i = 0; i < vhub->max_ports; i++)
273 		ast_vhub_del_dev(&vhub->ports[i].dev);
274 
275 	spin_lock_irqsave(&vhub->lock, flags);
276 
277 	/* Mask & ack all interrupts  */
278 	writel(0, vhub->regs + AST_VHUB_IER);
279 	writel(VHUB_IRQ_ACK_ALL, vhub->regs + AST_VHUB_ISR);
280 
281 	/* Pull device, leave PHY enabled */
282 	writel(VHUB_CTRL_PHY_CLK |
283 	       VHUB_CTRL_PHY_RESET_DIS,
284 	       vhub->regs + AST_VHUB_CTRL);
285 
286 	if (vhub->clk)
287 		clk_disable_unprepare(vhub->clk);
288 
289 	spin_unlock_irqrestore(&vhub->lock, flags);
290 
291 	if (vhub->ep0_bufs)
292 		dma_free_coherent(&pdev->dev,
293 				  AST_VHUB_EP0_MAX_PACKET *
294 				  (vhub->max_ports + 1),
295 				  vhub->ep0_bufs,
296 				  vhub->ep0_bufs_dma);
297 	vhub->ep0_bufs = NULL;
298 
299 	return 0;
300 }
301 
302 static int ast_vhub_probe(struct platform_device *pdev)
303 {
304 	enum usb_device_speed max_speed;
305 	struct ast_vhub *vhub;
306 	struct resource *res;
307 	int i, rc = 0;
308 	const struct device_node *np = pdev->dev.of_node;
309 
310 	vhub = devm_kzalloc(&pdev->dev, sizeof(*vhub), GFP_KERNEL);
311 	if (!vhub)
312 		return -ENOMEM;
313 
314 	rc = of_property_read_u32(np, "aspeed,vhub-downstream-ports",
315 				  &vhub->max_ports);
316 	if (rc < 0)
317 		vhub->max_ports = AST_VHUB_NUM_PORTS;
318 
319 	vhub->ports = devm_kcalloc(&pdev->dev, vhub->max_ports,
320 				   sizeof(*vhub->ports), GFP_KERNEL);
321 	if (!vhub->ports)
322 		return -ENOMEM;
323 
324 	rc = of_property_read_u32(np, "aspeed,vhub-generic-endpoints",
325 				  &vhub->max_epns);
326 	if (rc < 0)
327 		vhub->max_epns = AST_VHUB_NUM_GEN_EPs;
328 
329 	vhub->epns = devm_kcalloc(&pdev->dev, vhub->max_epns,
330 				  sizeof(*vhub->epns), GFP_KERNEL);
331 	if (!vhub->epns)
332 		return -ENOMEM;
333 
334 	spin_lock_init(&vhub->lock);
335 	vhub->pdev = pdev;
336 	vhub->port_irq_mask = GENMASK(VHUB_IRQ_DEV1_BIT + vhub->max_ports - 1,
337 				      VHUB_IRQ_DEV1_BIT);
338 
339 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
340 	vhub->regs = devm_ioremap_resource(&pdev->dev, res);
341 	if (IS_ERR(vhub->regs)) {
342 		dev_err(&pdev->dev, "Failed to map resources\n");
343 		return PTR_ERR(vhub->regs);
344 	}
345 	UDCDBG(vhub, "vHub@%pR mapped @%p\n", res, vhub->regs);
346 
347 	platform_set_drvdata(pdev, vhub);
348 
349 	vhub->clk = devm_clk_get(&pdev->dev, NULL);
350 	if (IS_ERR(vhub->clk)) {
351 		rc = PTR_ERR(vhub->clk);
352 		goto err;
353 	}
354 	rc = clk_prepare_enable(vhub->clk);
355 	if (rc) {
356 		dev_err(&pdev->dev, "Error couldn't enable clock (%d)\n", rc);
357 		goto err;
358 	}
359 
360 	/* Check if we need to limit the HW to USB1 */
361 	max_speed = usb_get_maximum_speed(&pdev->dev);
362 	if (max_speed != USB_SPEED_UNKNOWN && max_speed < USB_SPEED_HIGH)
363 		vhub->force_usb1 = true;
364 
365 	/* Mask & ack all interrupts before installing the handler */
366 	writel(0, vhub->regs + AST_VHUB_IER);
367 	writel(VHUB_IRQ_ACK_ALL, vhub->regs + AST_VHUB_ISR);
368 
369 	/* Find interrupt and install handler */
370 	vhub->irq = platform_get_irq(pdev, 0);
371 	if (vhub->irq < 0) {
372 		rc = vhub->irq;
373 		goto err;
374 	}
375 	rc = devm_request_irq(&pdev->dev, vhub->irq, ast_vhub_irq, 0,
376 			      KBUILD_MODNAME, vhub);
377 	if (rc) {
378 		dev_err(&pdev->dev, "Failed to request interrupt\n");
379 		goto err;
380 	}
381 
382 	/*
383 	 * Allocate DMA buffers for all EP0s in one chunk,
384 	 * one per port and one for the vHub itself
385 	 */
386 	vhub->ep0_bufs = dma_alloc_coherent(&pdev->dev,
387 					    AST_VHUB_EP0_MAX_PACKET *
388 					    (vhub->max_ports + 1),
389 					    &vhub->ep0_bufs_dma, GFP_KERNEL);
390 	if (!vhub->ep0_bufs) {
391 		dev_err(&pdev->dev, "Failed to allocate EP0 DMA buffers\n");
392 		rc = -ENOMEM;
393 		goto err;
394 	}
395 	UDCVDBG(vhub, "EP0 DMA buffers @%p (DMA 0x%08x)\n",
396 		vhub->ep0_bufs, (u32)vhub->ep0_bufs_dma);
397 
398 	/* Init vHub EP0 */
399 	ast_vhub_init_ep0(vhub, &vhub->ep0, NULL);
400 
401 	/* Init devices */
402 	for (i = 0; i < vhub->max_ports && rc == 0; i++)
403 		rc = ast_vhub_init_dev(vhub, i);
404 	if (rc)
405 		goto err;
406 
407 	/* Init hub emulation */
408 	rc = ast_vhub_init_hub(vhub);
409 	if (rc)
410 		goto err;
411 
412 	/* Initialize HW */
413 	ast_vhub_init_hw(vhub);
414 
415 	dev_info(&pdev->dev, "Initialized virtual hub in USB%d mode\n",
416 		 vhub->force_usb1 ? 1 : 2);
417 
418 	return 0;
419  err:
420 	ast_vhub_remove(pdev);
421 	return rc;
422 }
423 
424 static const struct of_device_id ast_vhub_dt_ids[] = {
425 	{
426 		.compatible = "aspeed,ast2400-usb-vhub",
427 	},
428 	{
429 		.compatible = "aspeed,ast2500-usb-vhub",
430 	},
431 	{
432 		.compatible = "aspeed,ast2600-usb-vhub",
433 	},
434 	{ }
435 };
436 MODULE_DEVICE_TABLE(of, ast_vhub_dt_ids);
437 
438 static struct platform_driver ast_vhub_driver = {
439 	.probe		= ast_vhub_probe,
440 	.remove		= ast_vhub_remove,
441 	.driver		= {
442 		.name	= KBUILD_MODNAME,
443 		.of_match_table	= ast_vhub_dt_ids,
444 	},
445 };
446 module_platform_driver(ast_vhub_driver);
447 
448 MODULE_DESCRIPTION("Aspeed vHub udc driver");
449 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
450 MODULE_LICENSE("GPL");
451