wusb: add the Wireless USB core (protocol)

Add the WUSB protocol (MMC management and device connection) code.
Signed-off-by: NDavid Vrabel <david.vrabel@csr.com>

drivers/usb/wusbcore/mmc.c

+/*
+ * WUSB Wire Adapter: Control/Data Streaming Interface (WUSB[8])
+ * MMC (Microscheduled Management Command) handling
+ *
+ * Copyright (C) 2005-2006 Intel Corporation
+ * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ *
+ * WUIEs and MMC IEs...well, they are almost the same at the end. MMC
+ * IEs are Wireless USB IEs that go into the MMC period...[what is
+ * that? look in Design-overview.txt].
+ *
+ *
+ * This is a simple subsystem to keep track of which IEs are being
+ * sent by the host in the MMC period.
+ *
+ * For each WUIE we ask to send, we keep it in an array, so we can
+ * request its removal later, or replace the content. They are tracked
+ * by pointer, so be sure to use the same pointer if you want to
+ * remove it or update the contents.
+ *
+ * FIXME:
+ *  - add timers that autoremove intervalled IEs?
+ */
+#include <linux/usb/wusb.h>
+#include "wusbhc.h"
+
+/* Initialize the MMCIEs handling mechanism */
+int wusbhc_mmcie_create(struct wusbhc *wusbhc)
+{
+	u8 mmcies = wusbhc->mmcies_max;
+	wusbhc->mmcie = kzalloc(mmcies * sizeof(wusbhc->mmcie[0]), GFP_KERNEL);
+	if (wusbhc->mmcie == NULL)
+		return -ENOMEM;
+	mutex_init(&wusbhc->mmcie_mutex);
+	return 0;
+}
+
+/* Release resources used by the MMCIEs handling mechanism */
+void wusbhc_mmcie_destroy(struct wusbhc *wusbhc)
+{
+	kfree(wusbhc->mmcie);
+}
+
+/*
+ * Add or replace an MMC Wireless USB IE.
+ *
+ * @interval:    See WUSB1.0[8.5.3.1]
+ * @repeat_cnt:  See WUSB1.0[8.5.3.1]
+ * @handle:      See WUSB1.0[8.5.3.1]
+ * @wuie:        Pointer to the header of the WUSB IE data to add.
+ *               MUST BE allocated in a kmalloc buffer (no stack or
+ *               vmalloc).
+ *               THE CALLER ALWAYS OWNS THE POINTER (we don't free it
+ *               on remove, we just forget about it).
+ * @returns:     0 if ok, < 0 errno code on error.
+ *
+ * Goes over the *whole* @wusbhc->mmcie array looking for (a) the
+ * first free spot and (b) if @wuie is already in the array (aka:
+ * transmitted in the MMCs) the spot were it is.
+ *
+ * If present, we "overwrite it" (update).
+ *
+ *
+ * NOTE: Need special ordering rules -- see below WUSB1.0 Table 7-38.
+ *       The host uses the handle as the 'sort' index. We
+ *       allocate the last one always for the WUIE_ID_HOST_INFO, and
+ *       the rest, first come first serve in inverse order.
+ *
+ *       Host software must make sure that it adds the other IEs in
+ *       the right order... the host hardware is responsible for
+ *       placing the WCTA IEs in the right place with the other IEs
+ *       set by host software.
+ *
+ * NOTE: we can access wusbhc->wa_descr without locking because it is
+ *       read only.
+ */
+int wusbhc_mmcie_set(struct wusbhc *wusbhc, u8 interval, u8 repeat_cnt,
+		     struct wuie_hdr *wuie)
+{
+	int result = -ENOBUFS;
+	struct device *dev = wusbhc->dev;
+	unsigned handle, itr;
+
+	/* Search a handle, taking into account the ordering */
+	mutex_lock(&wusbhc->mmcie_mutex);
+	switch (wuie->bIEIdentifier) {
+	case WUIE_ID_HOST_INFO:
+		/* Always last */
+		handle = wusbhc->mmcies_max - 1;
+		break;
+	case WUIE_ID_ISOCH_DISCARD:
+		dev_err(wusbhc->dev, "Special ordering case for WUIE ID 0x%x "
+			"unimplemented\n", wuie->bIEIdentifier);
+		result = -ENOSYS;
+		goto error_unlock;
+	default:
+		/* search for it or find the last empty slot */
+		handle = ~0;
+		for (itr = 0; itr < wusbhc->mmcies_max - 1; itr++) {
+			if (wusbhc->mmcie[itr] == wuie) {
+				handle = itr;
+				break;
+			}
+			if (wusbhc->mmcie[itr] == NULL)
+				handle = itr;
+		}
+		if (handle == ~0) {
+			if (printk_ratelimit())
+				dev_err(dev, "MMC handle space exhausted\n");
+			goto error_unlock;
+		}
+	}
+	result = (wusbhc->mmcie_add)(wusbhc, interval, repeat_cnt, handle,
+				     wuie);
+	if (result >= 0)
+		wusbhc->mmcie[handle] = wuie;
+error_unlock:
+	mutex_unlock(&wusbhc->mmcie_mutex);
+	return result;
+}
+EXPORT_SYMBOL_GPL(wusbhc_mmcie_set);
+
+/*
+ * Remove an MMC IE previously added with wusbhc_mmcie_set()
+ *
+ * @wuie	Pointer used to add the WUIE
+ */
+void wusbhc_mmcie_rm(struct wusbhc *wusbhc, struct wuie_hdr *wuie)
+{
+	int result;
+	struct device *dev = wusbhc->dev;
+	unsigned handle, itr;
+
+	mutex_lock(&wusbhc->mmcie_mutex);
+	for (itr = 0; itr < wusbhc->mmcies_max; itr++)
+		if (wusbhc->mmcie[itr] == wuie) {
+			handle = itr;
+			goto found;
+		}
+	mutex_unlock(&wusbhc->mmcie_mutex);
+	return;
+
+found:
+	result = (wusbhc->mmcie_rm)(wusbhc, handle);
+	if (result == 0)
+		wusbhc->mmcie[itr] = NULL;
+	else if (printk_ratelimit())
+		dev_err(dev, "MMC: Failed to remove IE %p (0x%02x)\n",
+			wuie, wuie->bIEIdentifier);
+	mutex_unlock(&wusbhc->mmcie_mutex);
+	return;
+}
+EXPORT_SYMBOL_GPL(wusbhc_mmcie_rm);
+
+/*
+ * wusbhc_start - start transmitting MMCs and accepting connections
+ * @wusbhc: the HC to start
+ * @chid: the CHID to use for this host
+ *
+ * Establishes a cluster reservation, enables device connections, and
+ * starts MMCs with appropriate DNTS parameters.
+ */
+int wusbhc_start(struct wusbhc *wusbhc, const struct wusb_ckhdid *chid)
+{
+	int result;
+	struct device *dev = wusbhc->dev;
+
+	WARN_ON(wusbhc->wuie_host_info != NULL);
+
+	result = wusbhc_rsv_establish(wusbhc);
+	if (result < 0) {
+		dev_err(dev, "cannot establish cluster reservation: %d\n",
+			result);
+		goto error_rsv_establish;
+	}
+
+	result = wusbhc_devconnect_start(wusbhc, chid);
+	if (result < 0) {
+		dev_err(dev, "error enabling device connections: %d\n", result);
+		goto error_devconnect_start;
+	}
+
+	result = wusbhc_sec_start(wusbhc);
+	if (result < 0) {
+		dev_err(dev, "error starting security in the HC: %d\n", result);
+		goto error_sec_start;
+	}
+	/* FIXME: the choice of the DNTS parameters is somewhat
+	 * arbitrary */
+	result = wusbhc->set_num_dnts(wusbhc, 0, 15);
+	if (result < 0) {
+		dev_err(dev, "Cannot set DNTS parameters: %d\n", result);
+		goto error_set_num_dnts;
+	}
+	result = wusbhc->start(wusbhc);
+	if (result < 0) {
+		dev_err(dev, "error starting wusbch: %d\n", result);
+		goto error_wusbhc_start;
+	}
+	wusbhc->active = 1;
+	return 0;
+
+error_wusbhc_start:
+	wusbhc_sec_stop(wusbhc);
+error_set_num_dnts:
+error_sec_start:
+	wusbhc_devconnect_stop(wusbhc);
+error_devconnect_start:
+	wusbhc_rsv_terminate(wusbhc);
+error_rsv_establish:
+	return result;
+}
+
+/*
+ * Disconnect all from the WUSB Channel
+ *
+ * Send a Host Disconnect IE in the MMC, wait, don't send it any more
+ */
+static int __wusbhc_host_disconnect_ie(struct wusbhc *wusbhc)
+{
+	int result = -ENOMEM;
+	struct wuie_host_disconnect *host_disconnect_ie;
+	might_sleep();
+	host_disconnect_ie = kmalloc(sizeof(*host_disconnect_ie), GFP_KERNEL);
+	if (host_disconnect_ie == NULL)
+		goto error_alloc;
+	host_disconnect_ie->hdr.bLength       = sizeof(*host_disconnect_ie);
+	host_disconnect_ie->hdr.bIEIdentifier = WUIE_ID_HOST_DISCONNECT;
+	result = wusbhc_mmcie_set(wusbhc, 0, 0, &host_disconnect_ie->hdr);
+	if (result < 0)
+		goto error_mmcie_set;
+
+	/* WUSB1.0[8.5.3.1 & 7.5.2] */
+	msleep(100);
+	wusbhc_mmcie_rm(wusbhc, &host_disconnect_ie->hdr);
+error_mmcie_set:
+	kfree(host_disconnect_ie);
+error_alloc:
+	return result;
+}
+
+/*
+ * wusbhc_stop - stop transmitting MMCs
+ * @wusbhc: the HC to stop
+ *
+ * Send a Host Disconnect IE, wait, remove all the MMCs (stop sending MMCs).
+ *
+ * If we can't allocate a Host Stop IE, screw it, we don't notify the
+ * devices we are disconnecting...
+ */
+void wusbhc_stop(struct wusbhc *wusbhc)
+{
+	if (wusbhc->active) {
+		wusbhc->active = 0;
+		wusbhc->stop(wusbhc);
+		wusbhc_sec_stop(wusbhc);
+		__wusbhc_host_disconnect_ie(wusbhc);
+		wusbhc_devconnect_stop(wusbhc);
+		wusbhc_rsv_terminate(wusbhc);
+	}
+}
+EXPORT_SYMBOL_GPL(wusbhc_stop);
+
+/*
+ * Change the CHID in a WUSB Channel
+ *
+ * If it is just a new CHID, send a Host Disconnect IE and then change
+ * the CHID IE.
+ */
+static int __wusbhc_chid_change(struct wusbhc *wusbhc,
+				const struct wusb_ckhdid *chid)
+{
+	int result = -ENOSYS;
+	struct device *dev = wusbhc->dev;
+	dev_err(dev, "%s() not implemented yet\n", __func__);
+	return result;
+
+	BUG_ON(wusbhc->wuie_host_info == NULL);
+	__wusbhc_host_disconnect_ie(wusbhc);
+	wusbhc->wuie_host_info->CHID = *chid;
+	result = wusbhc_mmcie_set(wusbhc, 0, 0, &wusbhc->wuie_host_info->hdr);
+	if (result < 0)
+		dev_err(dev, "Can't update Host Info WUSB IE: %d\n", result);
+	return result;
+}
+
+/*
+ * Set/reset/update a new CHID
+ *
+ * Depending on the previous state of the MMCs, start, stop or change
+ * the sent MMC. This effectively switches the host controller on and
+ * off (radio wise).
+ */
+int wusbhc_chid_set(struct wusbhc *wusbhc, const struct wusb_ckhdid *chid)
+{
+	int result = 0;
+
+	if (memcmp(chid, &wusb_ckhdid_zero, sizeof(chid)) == 0)
+		chid = NULL;
+
+	mutex_lock(&wusbhc->mutex);
+	if (wusbhc->active) {
+		if (chid)
+			result = __wusbhc_chid_change(wusbhc, chid);
+		else
+			wusbhc_stop(wusbhc);
+	} else {
+		if (chid)
+			wusbhc_start(wusbhc, chid);
+	}
+	mutex_unlock(&wusbhc->mutex);
+	return result;
+}
+EXPORT_SYMBOL_GPL(wusbhc_chid_set);