path: root/drivers/usb/musb/musb_gadget_ep0.c

// SPDX-License-Identifier: GPL-2.0
/*
 * MUSB OTG peripheral driver ep0 handling
 *
 * Copyright 2005 Mentor Graphics Corporation
 * Copyright (C) 2005-2006 by Texas Instruments
 * Copyright (C) 2006-2007 Nokia Corporation
 * Copyright (C) 2008-2009 MontaVista Software, Inc. <source@mvista.com>
 */

#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/timer.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/interrupt.h>

#include "musb_core.h"

/* ep0 is always musb->endpoints[0].ep_in */
#define	next_ep0_request(musb)	next_in_request(&(musb)->endpoints[0])

/*
 * locking note:  we use only the controller lock, for simpler correctness.
 * It's always held with IRQs blocked.
 *
 * It protects the ep0 request queue as well as ep0_state, not just the
 * controller and indexed registers.  And that lock stays held unless it
 * needs to be dropped to allow reentering this driver ... like upcalls to
 * the gadget driver, or adjusting endpoint halt status.
 */

static char *decode_ep0stage(u8 stage)
{
	switch (stage) {
	case MUSB_EP0_STAGE_IDLE:	return "idle";
	case MUSB_EP0_STAGE_SETUP:	return "setup";
	case MUSB_EP0_STAGE_TX:		return "in";
	case MUSB_EP0_STAGE_RX:		return "out";
	case MUSB_EP0_STAGE_ACKWAIT:	return "wait";
	case MUSB_EP0_STAGE_STATUSIN:	return "in/status";
	case MUSB_EP0_STAGE_STATUSOUT:	return "out/status";
	default:			return "?";
	}
}

/* handle a standard GET_STATUS request
 * Context:  caller holds controller lock
 */
static int service_tx_status_request(
	struct musb *musb,
	const struct usb_ctrlrequest *ctrlrequest)
{
	void __iomem	*mbase = musb->mregs;
	int handled = 1;
	u8 result[2], epnum = 0;
	const u8 recip = ctrlrequest->bRequestType & USB_RECIP_MASK;

	result[1] = 0;

	switch (recip) {
	case USB_RECIP_DEVICE:
		result[0] = musb->g.is_selfpowered << USB_DEVICE_SELF_POWERED;
		result[0] |= musb->may_wakeup << USB_DEVICE_REMOTE_WAKEUP;
		if (musb->g.is_otg) {
			result[0] |= musb->g.b_hnp_enable
				<< USB_DEVICE_B_HNP_ENABLE;
			result[0] |= musb->g.a_alt_hnp_support
				<< USB_DEVICE_A_ALT_HNP_SUPPORT;
			result[0] |= musb->g.a_hnp_support
				<< USB_DEVICE_A_HNP_SUPPORT;
		}
		break;

	case USB_RECIP_INTERFACE:
		result[0] = 0;
		break;

	case USB_RECIP_ENDPOINT: {
		int		is_in;
		struct musb_ep	*ep;
		u16		tmp;
		void __iomem	*regs;

		epnum = (u8) ctrlrequest->wIndex;
		if (!epnum) {
			result[0] = 0;
			break;
		}

		is_in = epnum & USB_DIR_IN;
		epnum &= 0x0f;
		if (epnum >= MUSB_C_NUM_EPS) {
			handled = -EINVAL;
			break;
		}

		if (is_in)
			ep = &musb->endpoints[epnum].ep_in;
		else
			ep = &musb->endpoints[epnum].ep_out;
		regs = musb->endpoints[epnum].regs;

		if (!ep->desc) {
			handled = -EINVAL;
			break;
		}

		musb_ep_select(mbase, epnum);
		if (is_in)
			tmp = musb_readw(regs, MUSB_TXCSR)
						& MUSB_TXCSR_P_SENDSTALL;
		else
			tmp = musb_readw(regs, MUSB_RXCSR)
						& MUSB_RXCSR_P_SENDSTALL;
		musb_ep_select(mbase, 0);

		result[0] = tmp ? 1 : 0;
		} break;

	default:
		/* class, vendor, etc ... delegate */
		handled = 0;
		break;
	}

	/* fill up the fifo; caller updates csr0 */
	if (handled > 0) {
		u16	len = le16_to_cpu(ctrlrequest->wLength);

		if (len > 2)
			len = 2;
		musb_write_fifo(&musb->endpoints[0], len, result);
	}

	return handled;
}

/*
 * handle a control-IN request, the end0 buffer contains the current request
 * that is supposed to be a standard control request. Assumes the fifo to
 * be at least 2 bytes long.
 *
 * @return 0 if the request was NOT HANDLED,
 * < 0 when error
 * > 0 when the request is processed
 *
 * Context:  caller holds controller lock
 */
static int
service_in_request(struct musb *musb, const struct usb_ctrlrequest *ctrlrequest)
{
	int handled = 0;	/* not handled */

	if ((ctrlrequest->bRequestType & USB_TYPE_MASK)
			== USB_TYPE_STANDARD) {
		switch (ctrlrequest->bRequest) {
		case USB_REQ_GET_STATUS:
			handled = service_tx_status_request(musb,
					ctrlrequest);
			break;

		/* case USB_REQ_SYNC_FRAME: */

		default:
			break;
		}
	}
	return handled;
}

/*
 * Context:  caller holds controller lock
 */
static void musb_g_ep0_giveback(struct musb *musb, struct usb_request *req)
{
	musb_g_giveback(&musb->endpoints[0].ep_in, req, 0);
}

/*
 * Tries to start B-device HNP negotiation if enabled via sysfs
 */
static inline void musb_try_b_hnp_enable(struct musb *musb)
{
	void __iomem	*mbase = musb->mregs;
	u8		devctl;

	musb_dbg(musb, "HNP: Setting HR");
	devctl = musb_readb(mbase, MUSB_DEVCTL);
	musb_writeb(mbase, MUSB_DEVCTL, devctl | MUSB_DEVCTL_HR);
}

/*
 * Handle all control requests with no DATA stage, including standard
 * requests such as:
 * USB_REQ_SET_CONFIGURATION, USB_REQ_SET_INTERFACE, unrecognized
 *	always delegated to the gadget driver
 * USB_REQ_SET_ADDRESS, USB_REQ_CLEAR_FEATURE, USB_REQ_SET_FEATURE
 *	always handled here, except for class/vendor/... features
 *
 * Context:  caller holds cont