wimax: move out to staging

There are no known users of this driver as of October 2020, and it will
be removed unless someone turns out to still need it in future releases.

According to https://en.wikipedia.org/wiki/List_of_WiMAX_networks, there
have been many public wimax networks, but it appears that many of these
have migrated to LTE or discontinued their service altogether.
As most PCs and phones lack WiMAX hardware support, the remaining
networks tend to use standalone routers. These almost certainly
run Linux, but not a modern kernel or the mainline wimax driver stack.

NetworkManager appears to have dropped userspace support in 2015
https://bugzilla.gnome.org/show_bug.cgi?id=747846, the
www.linuxwimax.org
site had already shut down earlier.

WiMax is apparently still being deployed on airport campus networks
("AeroMACS"), but in a frequency band that was not supported by the old
Intel 2400m (used in Sandy Bridge laptops and earlier), which is the
only driver using the kernel's wimax stack.

Move all files into drivers/staging/wimax, including the uapi header
files and documentation, to make it easier to remove it when it gets
to that. Only minimal changes are made to the source files, in order
to make it possible to port patches across the move.

Also remove the MAINTAINERS entry that refers to a broken mailing
list and website.

Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-By: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Suggested-by: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 196 insertions, 0 deletions

diff --git a/drivers/staging/wimax/i2400m/op-rfkill.c b/drivers/staging/wimax/i2400m/op-rfkill.c
new file mode 100644
index 000000000000..fbddf2e18c14
--- /dev/null
+++ b/drivers/staging/wimax/i2400m/op-rfkill.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel Wireless WiMAX Connection 2400m
+ * Implement backend for the WiMAX stack rfkill support
+ *
+ * Copyright (C) 2007-2008 Intel Corporation <linux-wimax@intel.com>
+ * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
+ *
+ * The WiMAX kernel stack integrates into RF-Kill and keeps the
+ * switches's status. We just need to:
+ *
+ * - report changes in the HW RF Kill switch [with
+ *   wimax_rfkill_{sw,hw}_report(), which happens when we detect those
+ *   indications coming through hardware reports]. We also do it on
+ *   initialization to let the stack know the initial HW state.
+ *
+ * - implement indications from the stack to change the SW RF Kill
+ *   switch (coming from sysfs, the wimax stack or user space).
+ */
+#include "i2400m.h"
+#include "linux-wimax-i2400m.h"
+#include <linux/slab.h>
+
+
+
+#define D_SUBMODULE rfkill
+#include "debug-levels.h"
+
+/*
+ * Return true if the i2400m radio is in the requested wimax_rf_state state
+ *
+ */
+static
+int i2400m_radio_is(struct i2400m *i2400m, enum wimax_rf_state state)
+{
+	if (state == WIMAX_RF_OFF)
+		return i2400m->state == I2400M_SS_RF_OFF
+			|| i2400m->state == I2400M_SS_RF_SHUTDOWN;
+	else if (state == WIMAX_RF_ON)
+		/* state == WIMAX_RF_ON */
+		return i2400m->state != I2400M_SS_RF_OFF
+			&& i2400m->state != I2400M_SS_RF_SHUTDOWN;
+	else {
+		BUG();
+		return -EINVAL;	/* shut gcc warnings on certain arches */
+	}
+}
+
+
+/*
+ * WiMAX stack operation: implement SW RFKill toggling
+ *
+ * @wimax_dev: device descriptor
+ * @skb: skb where the message has been received; skb->data is
+ *       expected to point to the message payload.
+ * @genl_info: passed by the generic netlink layer
+ *
+ * Generic Netlink will call this function when a message is sent from
+ * userspace to change the software RF-Kill switch status.
+ *
+ * This function will set the device's software RF-Kill switch state to
+ * match what is requested.
+ *
+ * NOTE: the i2400m has a strict state machine; we can only set the
+ *       RF-Kill switch when it is on, the HW RF-Kill is on and the
+ *       device is initialized. So we ignore errors steaming from not
+ *       being in the right state (-EILSEQ).
+ */
+int i2400m_op_rfkill_sw_toggle(struct wimax_dev *wimax_dev,
+			       enum wimax_rf_state state)
+{
+	int result;
+	struct i2400m *i2400m = wimax_dev_to_i2400m(wimax_dev);
+	struct device *dev = i2400m_dev(i2400m);
+	struct sk_buff *ack_skb;
+	struct {
+		struct i2400m_l3l4_hdr hdr;
+		struct i2400m_tlv_rf_operation sw_rf;
+	} __packed *cmd;
+	char strerr[32];
+
+	d_fnstart(4, dev, "(wimax_dev %p state %d)\n", wimax_dev, state);
+
+	result = -ENOMEM;
+	cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
+	if (cmd == NULL)
+		goto error_alloc;
+	cmd->hdr.type = cpu_to_le16(I2400M_MT_CMD_RF_CONTROL);
+	cmd->hdr.length = sizeof(cmd->sw_rf);
+	cmd->hdr.version = cpu_to_le16(I2400M_L3L4_VERSION);
+	cmd->sw_rf.hdr.type = cpu_to_le16(I2400M_TLV_RF_OPERATION);
+	cmd->sw_rf.hdr.length = cpu_to_le16(sizeof(cmd->sw_rf.status));
+	switch (state) {
+	case WIMAX_RF_OFF:	/* RFKILL ON, radio OFF */
+		cmd->sw_rf.status = cpu_to_le32(2);
+		break;
+	case WIMAX_RF_ON:	/* RFKILL OFF, radio ON */
+		cmd->sw_rf.status = cpu_to_le32(1);
+		break;
+	default:
+		BUG();
+	}
+
+	ack_skb = i2400m_msg_to_dev(i2400m, cmd, sizeof(*cmd));
+	result = PTR_ERR(ack_skb);
+	if (IS_ERR(ack_skb)) {
+		dev_err(dev, "Failed to issue 'RF Control' command: %d\n",
+			result);
+		goto error_msg_to_dev;
+	}
+	result = i2400m_msg_check_status(wimax_msg_data(ack_skb),
+					 strerr, sizeof(strerr));
+	if (result < 0) {
+		dev_err(dev, "'RF Control' (0x%04x) command failed: %d - %s\n",
+			I2400M_MT_CMD_RF_CONTROL, result, strerr);
+		goto error_cmd;
+	}
+
+	/* Now we wait for the state to change to RADIO_OFF or RADIO_ON */
+	result = wait_event_timeout(
+		i2400m->state_wq, i2400m_radio_is(i2400m, state),
+		5 * HZ);
+	if (result == 0)
+		result = -ETIMEDOUT;
+	if (result < 0)
+		dev_err(dev, "Error waiting for device to toggle RF state: "
+			"%d\n", result);
+	result = 0;
+error_cmd:
+	kfree_skb(ack_skb);
+error_msg_to_dev:
+error_alloc:
+	d_fnend(4, dev, "(wimax_dev %p state %d) = %d\n",
+		wimax_dev, state, result);
+	kfree(cmd);
+	return result;
+}
+
+
+/*
+ * Inform the WiMAX stack of changes in the RF Kill switches reported
+ * by the device
+ *
+ * @i2400m: device descriptor
+ * @rfss: TLV for RF Switches status; already validated
+ *
+ * NOTE: the reports on RF switch status cannot be trusted
+ *       or used until the device is in a state of RADIO_OFF
+ *       or greater.
+ */
+void i2400m_report_tlv_rf_switches_status(
+	struct i2400m *i2400m,
+	const struct i2400m_tlv_rf_switches_status *rfss)
+{
+	struct device *dev = i2400m_dev(i2400m);
+	enum i2400m_rf_switch_status hw, sw;
+	enum wimax_st wimax_state;
+
+	sw = le32_to_cpu(rfss->sw_rf_switch);
+	hw = le32_to_cpu(rfss->hw_rf_switch);
+
+	d_fnstart(3, dev, "(i2400m %p rfss %p [hw %u sw %u])\n",
+		  i2400m, rfss, hw, sw);
+	/* We only process rw switch evens when the device has been
+	 * fully initialized */
+	wimax_state = wimax_state_get(&i2400m->wimax_dev);
+	if (wimax_state < WIMAX_ST_RADIO_OFF) {
+		d_printf(3, dev, "ignoring RF switches report, state %u\n",
+			 wimax_state);
+		goto out;
+	}
+	switch (sw) {
+	case I2400M_RF_SWITCH_ON:	/* RF Kill disabled (radio on) */
+		wimax_report_rfkill_sw(&i2400m->wimax_dev, WIMAX_RF_ON);
+		break;
+	case I2400M_RF_SWITCH_OFF:	/* RF Kill enabled (radio off) */
+		wimax_report_rfkill_sw(&i2400m->wimax_dev, WIMAX_RF_OFF);
+		break;
+	default:
+		dev_err(dev, "HW BUG? Unknown RF SW state 0x%x\n", sw);
+	}
+
+	switch (hw) {
+	case I2400M_RF_SWITCH_ON:	/* RF Kill disabled (radio on) */
+		wimax_report_rfkill_hw(&i2400m->wimax_dev, WIMAX_RF_ON);
+		break;
+	case I2400M_RF_SWITCH_OFF:	/* RF Kill enabled (radio off) */
+		wimax_report_rfkill_hw(&i2400m->wimax_dev, WIMAX_RF_OFF);
+		break;
+	default:
+		dev_err(dev, "HW BUG? Unknown RF HW state 0x%x\n", hw);
+	}
+out:
+	d_fnend(3, dev, "(i2400m %p rfss %p [hw %u sw %u]) = void\n",
+		i2400m, rfss, hw, sw);
+}