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 
40 	EPVDBG(ep, "completing request @%p, status %d\n", req, status);
41 
42 	list_del_init(&req->queue);
43 
44 	if (req->req.status == -EINPROGRESS)
45 		req->req.status = status;
46 
47 	if (req->req.dma) {
48 		if (!WARN_ON(!ep->dev))
49 			usb_gadget_unmap_request(&ep->dev->gadget,
50 						 &req->req, ep->epn.is_in);
51 		req->req.dma = 0;
52 	}
53 
54 	/*
55 	 * If this isn't an internal EP0 request, call the core
56 	 * to call the gadget completion.
57 	 */
58 	if (!internal) {
59 		spin_unlock(&ep->vhub->lock);
60 		usb_gadget_giveback_request(&ep->ep, &req->req);
61 		spin_lock(&ep->vhub->lock);
62 	}
63 }
64 
65 void ast_vhub_nuke(struct ast_vhub_ep *ep, int status)
66 {
67 	struct ast_vhub_req *req;
68 	int count = 0;
69 
70 	/* Beware, lock will be dropped & req-acquired by done() */
71 	while (!list_empty(&ep->queue)) {
72 		req = list_first_entry(&ep->queue, struct ast_vhub_req, queue);
73 		ast_vhub_done(ep, req, status);
74 		count++;
75 	}
76 	if (count)
77 		EPDBG(ep, "Nuked %d request(s)\n", count);
78 }
79 
80 struct usb_request *ast_vhub_alloc_request(struct usb_ep *u_ep,
81 					   gfp_t gfp_flags)
82 {
83 	struct ast_vhub_req *req;
84 
85 	req = kzalloc(sizeof(*req), gfp_flags);
86 	if (!req)
87 		return NULL;
88 	return &req->req;
89 }
90 
91 void ast_vhub_free_request(struct usb_ep *u_ep, struct usb_request *u_req)
92 {
93 	struct ast_vhub_req *req = to_ast_req(u_req);
94 
95 	kfree(req);
96 }
97 
98 static irqreturn_t ast_vhub_irq(int irq, void *data)
99 {
100 	struct ast_vhub *vhub = data;
101 	irqreturn_t iret = IRQ_NONE;
102 	u32 i, istat;
103 
104 	/* Stale interrupt while tearing down */
105 	if (!vhub->ep0_bufs)
106 		return IRQ_NONE;
107 
108 	spin_lock(&vhub->lock);
109 
110 	/* Read and ACK interrupts */
111 	istat = readl(vhub->regs + AST_VHUB_ISR);
112 	if (!istat)
113 		goto bail;
114 	writel(istat, vhub->regs + AST_VHUB_ISR);
115 	iret = IRQ_HANDLED;
116 
117 	UDCVDBG(vhub, "irq status=%08x, ep_acks=%08x ep_nacks=%08x\n",
118 	       istat,
119 	       readl(vhub->regs + AST_VHUB_EP_ACK_ISR),
120 	       readl(vhub->regs + AST_VHUB_EP_NACK_ISR));
121 
122 	/* Handle generic EPs first */
123 	if (istat & VHUB_IRQ_EP_POOL_ACK_STALL) {
124 		u32 ep_acks = readl(vhub->regs + AST_VHUB_EP_ACK_ISR);
125 		writel(ep_acks, vhub->regs + AST_VHUB_EP_ACK_ISR);
126 
127 		for (i = 0; ep_acks && i < vhub->max_epns; i++) {
128 			u32 mask = VHUB_EP_IRQ(i);
129 			if (ep_acks & mask) {
130 				ast_vhub_epn_ack_irq(&vhub->epns[i]);
131 				ep_acks &= ~mask;
132 			}
133 		}
134 	}
135 
136 	/* Handle device interrupts */
137 	for (i = 0; i < vhub->max_ports; i++) {
138 		u32 dev_mask = VHUB_IRQ_DEVICE1 << i;
139 
140 		if (istat & dev_mask)
141 			ast_vhub_dev_irq(&vhub->ports[i].dev);
142 	}
143 
144 	/* Handle top-level vHub EP0 interrupts */
145 	if (istat & (VHUB_IRQ_HUB_EP0_OUT_ACK_STALL |
146 		     VHUB_IRQ_HUB_EP0_IN_ACK_STALL |
147 		     VHUB_IRQ_HUB_EP0_SETUP)) {
148 		if (istat & VHUB_IRQ_HUB_EP0_IN_ACK_STALL)
149 			ast_vhub_ep0_handle_ack(&vhub->ep0, true);
150 		if (istat & VHUB_IRQ_HUB_EP0_OUT_ACK_STALL)
151 			ast_vhub_ep0_handle_ack(&vhub->ep0, false);
152 		if (istat & VHUB_IRQ_HUB_EP0_SETUP)
153 			ast_vhub_ep0_handle_setup(&vhub->ep0);
154 	}
155 
156 	/* Various top level bus events */
157 	if (istat & (VHUB_IRQ_BUS_RESUME |
158 		     VHUB_IRQ_BUS_SUSPEND |
159 		     VHUB_IRQ_BUS_RESET)) {
160 		if (istat & VHUB_IRQ_BUS_RESUME)
161 			ast_vhub_hub_resume(vhub);
162 		if (istat & VHUB_IRQ_BUS_SUSPEND)
163 			ast_vhub_hub_suspend(vhub);
164 		if (istat & VHUB_IRQ_BUS_RESET)
165 			ast_vhub_hub_reset(vhub);
166 	}
167 
168  bail:
169 	spin_unlock(&vhub->lock);
170 	return iret;
171 }
172 
173 void ast_vhub_init_hw(struct ast_vhub *vhub)
174 {
175 	u32 ctrl, port_mask, epn_mask;
176 
177 	UDCDBG(vhub,"(Re)Starting HW ...\n");
178 
179 	/* Enable PHY */
180 	ctrl = VHUB_CTRL_PHY_CLK |
181 		VHUB_CTRL_PHY_RESET_DIS;
182 
183        /*
184 	* We do *NOT* set the VHUB_CTRL_CLK_STOP_SUSPEND bit
185 	* to stop the logic clock during suspend because
186 	* it causes the registers to become inaccessible and
187 	* we haven't yet figured out a good wayt to bring the
188 	* controller back into life to issue a wakeup.
189 	*/
190 
191 	/*
192 	 * Set some ISO & split control bits according to Aspeed
193 	 * recommendation
194 	 *
195 	 * VHUB_CTRL_ISO_RSP_CTRL: When set tells the HW to respond
196 	 * with 0 bytes data packet to ISO IN endpoints when no data
197 	 * is available.
198 	 *
199 	 * VHUB_CTRL_SPLIT_IN: This makes a SOF complete a split IN
200 	 * transaction.
201 	 */
202 	ctrl |= VHUB_CTRL_ISO_RSP_CTRL | VHUB_CTRL_SPLIT_IN;
203 	writel(ctrl, vhub->regs + AST_VHUB_CTRL);
204 	udelay(1);
205 
206 	/* Set descriptor ring size */
207 	if (AST_VHUB_DESCS_COUNT == 256) {
208 		ctrl |= VHUB_CTRL_LONG_DESC;
209 		writel(ctrl, vhub->regs + AST_VHUB_CTRL);
210 	} else {
211 		BUILD_BUG_ON(AST_VHUB_DESCS_COUNT != 32);
212 	}
213 
214 	/* Reset all devices */
215 	port_mask = GENMASK(vhub->max_ports, 1);
216 	writel(VHUB_SW_RESET_ROOT_HUB |
217 	       VHUB_SW_RESET_DMA_CONTROLLER |
218 	       VHUB_SW_RESET_EP_POOL |
219 	       port_mask, vhub->regs + AST_VHUB_SW_RESET);
220 	udelay(1);
221 	writel(0, vhub->regs + AST_VHUB_SW_RESET);
222 
223 	/* Disable and cleanup EP ACK/NACK interrupts */
224 	epn_mask = GENMASK(vhub->max_epns - 1, 0);
225 	writel(0, vhub->regs + AST_VHUB_EP_ACK_IER);
226 	writel(0, vhub->regs + AST_VHUB_EP_NACK_IER);
227 	writel(epn_mask, vhub->regs + AST_VHUB_EP_ACK_ISR);
228 	writel(epn_mask, vhub->regs + AST_VHUB_EP_NACK_ISR);
229 
230 	/* Default settings for EP0, enable HW hub EP1 */
231 	writel(0, vhub->regs + AST_VHUB_EP0_CTRL);
232 	writel(VHUB_EP1_CTRL_RESET_TOGGLE |
233 	       VHUB_EP1_CTRL_ENABLE,
234 	       vhub->regs + AST_VHUB_EP1_CTRL);
235 	writel(0, vhub->regs + AST_VHUB_EP1_STS_CHG);
236 
237 	/* Configure EP0 DMA buffer */
238 	writel(vhub->ep0.buf_dma, vhub->regs + AST_VHUB_EP0_DATA);
239 
240 	/* Clear address */
241 	writel(0, vhub->regs + AST_VHUB_CONF);
242 
243 	/* Pullup hub (activate on host) */
244 	if (vhub->force_usb1)
245 		ctrl |= VHUB_CTRL_FULL_SPEED_ONLY;
246 
247 	ctrl |= VHUB_CTRL_UPSTREAM_CONNECT;
248 	writel(ctrl, vhub->regs + AST_VHUB_CTRL);
249 
250 	/* Enable some interrupts */
251 	writel(VHUB_IRQ_HUB_EP0_IN_ACK_STALL |
252 	       VHUB_IRQ_HUB_EP0_OUT_ACK_STALL |
253 	       VHUB_IRQ_HUB_EP0_SETUP |
254 	       VHUB_IRQ_EP_POOL_ACK_STALL |
255 	       VHUB_IRQ_BUS_RESUME |
256 	       VHUB_IRQ_BUS_SUSPEND |
257 	       VHUB_IRQ_BUS_RESET,
258 	       vhub->regs + AST_VHUB_IER);
259 }
260 
261 static int ast_vhub_remove(struct platform_device *pdev)
262 {
263 	struct ast_vhub *vhub = platform_get_drvdata(pdev);
264 	unsigned long flags;
265 	int i;
266 
267 	if (!vhub || !vhub->regs)
268 		return 0;
269 
270 	/* Remove devices */
271 	for (i = 0; i < vhub->max_ports; i++)
272 		ast_vhub_del_dev(&vhub->ports[i].dev);
273 
274 	spin_lock_irqsave(&vhub->lock, flags);
275 
276 	/* Mask & ack all interrupts  */
277 	writel(0, vhub->regs + AST_VHUB_IER);
278 	writel(VHUB_IRQ_ACK_ALL, vhub->regs + AST_VHUB_ISR);
279 
280 	/* Pull device, leave PHY enabled */
281 	writel(VHUB_CTRL_PHY_CLK |
282 	       VHUB_CTRL_PHY_RESET_DIS,
283 	       vhub->regs + AST_VHUB_CTRL);
284 
285 	if (vhub->clk)
286 		clk_disable_unprepare(vhub->clk);
287 
288 	spin_unlock_irqrestore(&vhub->lock, flags);
289 
290 	if (vhub->ep0_bufs)
291 		dma_free_coherent(&pdev->dev,
292 				  AST_VHUB_EP0_MAX_PACKET *
293 				  (vhub->max_ports + 1),
294 				  vhub->ep0_bufs,
295 				  vhub->ep0_bufs_dma);
296 	vhub->ep0_bufs = NULL;
297 
298 	return 0;
299 }
300 
301 static int ast_vhub_probe(struct platform_device *pdev)
302 {
303 	enum usb_device_speed max_speed;
304 	struct ast_vhub *vhub;
305 	struct resource *res;
306 	int i, rc = 0;
307 	const struct device_node *np = pdev->dev.of_node;
308 
309 	vhub = devm_kzalloc(&pdev->dev, sizeof(*vhub), GFP_KERNEL);
310 	if (!vhub)
311 		return -ENOMEM;
312 
313 	rc = of_property_read_u32(np, "aspeed,vhub-downstream-ports",
314 				  &vhub->max_ports);
315 	if (rc < 0)
316 		vhub->max_ports = AST_VHUB_NUM_PORTS;
317 
318 	vhub->ports = devm_kcalloc(&pdev->dev, vhub->max_ports,
319 				   sizeof(*vhub->ports), GFP_KERNEL);
320 	if (!vhub->ports)
321 		return -ENOMEM;
322 
323 	rc = of_property_read_u32(np, "aspeed,vhub-generic-endpoints",
324 				  &vhub->max_epns);
325 	if (rc < 0)
326 		vhub->max_epns = AST_VHUB_NUM_GEN_EPs;
327 
328 	vhub->epns = devm_kcalloc(&pdev->dev, vhub->max_epns,
329 				  sizeof(*vhub->epns), GFP_KERNEL);
330 	if (!vhub->epns)
331 		return -ENOMEM;
332 
333 	spin_lock_init(&vhub->lock);
334 	vhub->pdev = pdev;
335 
336 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
337 	vhub->regs = devm_ioremap_resource(&pdev->dev, res);
338 	if (IS_ERR(vhub->regs)) {
339 		dev_err(&pdev->dev, "Failed to map resources\n");
340 		return PTR_ERR(vhub->regs);
341 	}
342 	UDCDBG(vhub, "vHub@%pR mapped @%p\n", res, vhub->regs);
343 
344 	platform_set_drvdata(pdev, vhub);
345 
346 	vhub->clk = devm_clk_get(&pdev->dev, NULL);
347 	if (IS_ERR(vhub->clk)) {
348 		rc = PTR_ERR(vhub->clk);
349 		goto err;
350 	}
351 	rc = clk_prepare_enable(vhub->clk);
352 	if (rc) {
353 		dev_err(&pdev->dev, "Error couldn't enable clock (%d)\n", rc);
354 		goto err;
355 	}
356 
357 	/* Check if we need to limit the HW to USB1 */
358 	max_speed = usb_get_maximum_speed(&pdev->dev);
359 	if (max_speed != USB_SPEED_UNKNOWN && max_speed < USB_SPEED_HIGH)
360 		vhub->force_usb1 = true;
361 
362 	/* Mask & ack all interrupts before installing the handler */
363 	writel(0, vhub->regs + AST_VHUB_IER);
364 	writel(VHUB_IRQ_ACK_ALL, vhub->regs + AST_VHUB_ISR);
365 
366 	/* Find interrupt and install handler */
367 	vhub->irq = platform_get_irq(pdev, 0);
368 	if (vhub->irq < 0) {
369 		rc = vhub->irq;
370 		goto err;
371 	}
372 	rc = devm_request_irq(&pdev->dev, vhub->irq, ast_vhub_irq, 0,
373 			      KBUILD_MODNAME, vhub);
374 	if (rc) {
375 		dev_err(&pdev->dev, "Failed to request interrupt\n");
376 		goto err;
377 	}
378 
379 	/*
380 	 * Allocate DMA buffers for all EP0s in one chunk,
381 	 * one per port and one for the vHub itself
382 	 */
383 	vhub->ep0_bufs = dma_alloc_coherent(&pdev->dev,
384 					    AST_VHUB_EP0_MAX_PACKET *
385 					    (vhub->max_ports + 1),
386 					    &vhub->ep0_bufs_dma, GFP_KERNEL);
387 	if (!vhub->ep0_bufs) {
388 		dev_err(&pdev->dev, "Failed to allocate EP0 DMA buffers\n");
389 		rc = -ENOMEM;
390 		goto err;
391 	}
392 	UDCVDBG(vhub, "EP0 DMA buffers @%p (DMA 0x%08x)\n",
393 		vhub->ep0_bufs, (u32)vhub->ep0_bufs_dma);
394 
395 	/* Init vHub EP0 */
396 	ast_vhub_init_ep0(vhub, &vhub->ep0, NULL);
397 
398 	/* Init devices */
399 	for (i = 0; i < vhub->max_ports && rc == 0; i++)
400 		rc = ast_vhub_init_dev(vhub, i);
401 	if (rc)
402 		goto err;
403 
404 	/* Init hub emulation */
405 	ast_vhub_init_hub(vhub);
406 
407 	/* Initialize HW */
408 	ast_vhub_init_hw(vhub);
409 
410 	dev_info(&pdev->dev, "Initialized virtual hub in USB%d mode\n",
411 		 vhub->force_usb1 ? 1 : 2);
412 
413 	return 0;
414  err:
415 	ast_vhub_remove(pdev);
416 	return rc;
417 }
418 
419 static const struct of_device_id ast_vhub_dt_ids[] = {
420 	{
421 		.compatible = "aspeed,ast2400-usb-vhub",
422 	},
423 	{
424 		.compatible = "aspeed,ast2500-usb-vhub",
425 	},
426 	{
427 		.compatible = "aspeed,ast2600-usb-vhub",
428 	},
429 	{ }
430 };
431 MODULE_DEVICE_TABLE(of, ast_vhub_dt_ids);
432 
433 static struct platform_driver ast_vhub_driver = {
434 	.probe		= ast_vhub_probe,
435 	.remove		= ast_vhub_remove,
436 	.driver		= {
437 		.name	= KBUILD_MODNAME,
438 		.of_match_table	= ast_vhub_dt_ids,
439 	},
440 };
441 module_platform_driver(ast_vhub_driver);
442 
443 MODULE_DESCRIPTION("Aspeed vHub udc driver");
444 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
445 MODULE_LICENSE("GPL");
446