add mt7601u driver

Add support for the simplest of MediaTek Wi-Fi devices - MT7601U.
It is a single stream bgn chip with no bells or whistles.
This driver is partially based on Felix's mt76 but IMHO it doesn't
make sense to merge the two right now because MT7601U is a design
somewhere between old Ralink devices and new Mediatek chips.  There
wouldn't be all that much code sharing with the devices mt76 supports.
Situation may obviously change when someone decides to extend m76 with
support for the more recent USB dongles.

The driver supports only station mode.  I'm hoping to add AP support
when time allows.

This driver sat on GitHub for quite a while and got some testing there:
http://github.com/kuba-moo/mt7601u

Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

1 files changed, 360 insertions, 0 deletions

diff --git a/drivers/net/wireless/mediatek/mt7601u/usb.c b/drivers/net/wireless/mediatek/mt7601u/usb.c
new file mode 100644
index 000000000000..99e2b3997bfa
--- /dev/null
+++ b/drivers/net/wireless/mediatek/mt7601u/usb.c
@@ -0,0 +1,360 @@
+/*
+ * Copyright (C) 2015 Jakub Kicinski <kubakici@wp.pl>
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+
+#include "mt7601u.h"
+#include "usb.h"
+#include "trace.h"
+
+static struct usb_device_id mt7601u_device_table[] = {
+	{ USB_DEVICE(0x0b05, 0x17d3) },
+	{ USB_DEVICE(0x0e8d, 0x760a) },
+	{ USB_DEVICE(0x0e8d, 0x760b) },
+	{ USB_DEVICE(0x13d3, 0x3431) },
+	{ USB_DEVICE(0x13d3, 0x3434) },
+	{ USB_DEVICE(0x148f, 0x7601) },
+	{ USB_DEVICE(0x148f, 0x760a) },
+	{ USB_DEVICE(0x148f, 0x760b) },
+	{ USB_DEVICE(0x148f, 0x760c) },
+	{ USB_DEVICE(0x148f, 0x760d) },
+	{ USB_DEVICE(0x2001, 0x3d04) },
+	{ USB_DEVICE(0x2717, 0x4106) },
+	{ USB_DEVICE(0x2955, 0x0001) },
+	{ USB_DEVICE(0x2955, 0x1001) },
+	{ USB_DEVICE(0x2a5f, 0x1000) },
+	{ USB_DEVICE(0x7392, 0x7710) },
+	{ 0, }
+};
+
+bool mt7601u_usb_alloc_buf(struct mt7601u_dev *dev, size_t len,
+			   struct mt7601u_dma_buf *buf)
+{
+	struct usb_device *usb_dev = mt7601u_to_usb_dev(dev);
+
+	buf->len = len;
+	buf->urb = usb_alloc_urb(0, GFP_KERNEL);
+	buf->buf = usb_alloc_coherent(usb_dev, buf->len, GFP_KERNEL, &buf->dma);
+
+	return !buf->urb || !buf->buf;
+}
+
+void mt7601u_usb_free_buf(struct mt7601u_dev *dev, struct mt7601u_dma_buf *buf)
+{
+	struct usb_device *usb_dev = mt7601u_to_usb_dev(dev);
+
+	usb_free_coherent(usb_dev, buf->len, buf->buf, buf->dma);
+	usb_free_urb(buf->urb);
+}
+
+int mt7601u_usb_submit_buf(struct mt7601u_dev *dev, int dir, int ep_idx,
+			   struct mt7601u_dma_buf *buf, gfp_t gfp,
+			   usb_complete_t complete_fn, void *context)
+{
+	struct usb_device *usb_dev = mt7601u_to_usb_dev(dev);
+	unsigned pipe;
+	int ret;
+
+	if (dir == USB_DIR_IN)
+		pipe = usb_rcvbulkpipe(usb_dev, dev->in_eps[ep_idx]);
+	else
+		pipe = usb_sndbulkpipe(usb_dev, dev->out_eps[ep_idx]);
+
+	usb_fill_bulk_urb(buf->urb, usb_dev, pipe, buf->buf, buf->len,
+			  complete_fn, context);
+	buf->urb->transfer_dma = buf->dma;
+	buf->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+	trace_mt_submit_urb(dev, buf->urb);
+	ret = usb_submit_urb(buf->urb, gfp);
+	if (ret)
+		dev_err(dev->dev, "Error: submit URB dir:%d ep:%d failed:%d\n",
+			dir, ep_idx, ret);
+	return ret;
+}
+
+void mt7601u_complete_urb(struct urb *urb)
+{
+	struct completion *cmpl = urb->context;
+
+	complete(cmpl);
+}
+
+static int
+__mt7601u_vendor_request(struct mt7601u_dev *dev, const u8 req,
+			 const u8 direction, const u16 val, const u16 offset,
+			 void *buf, const size_t buflen)
+{
+	int i, ret;
+	struct usb_device *usb_dev = mt7601u_to_usb_dev(dev);
+	const u8 req_type = direction | USB_TYPE_VENDOR | USB_RECIP_DEVICE;
+	const unsigned int pipe = (direction == USB_DIR_IN) ?
+		usb_rcvctrlpipe(usb_dev, 0) : usb_sndctrlpipe(usb_dev, 0);
+
+	for (i = 0; i < MT_VEND_REQ_MAX_RETRY; i++) {
+		ret = usb_control_msg(usb_dev, pipe, req, req_type,
+				      val, offset, buf, buflen,
+				      MT_VEND_REQ_TOUT_MS);
+		trace_mt_vend_req(dev, pipe, req, req_type, val, offset,
+				  buf, buflen, ret);
+
+		if (ret >= 0 || ret == -ENODEV)
+			return ret;
+
+		msleep(5);
+	}
+
+	dev_err(dev->dev, "Vendor request req:%02x off:%04x failed:%d\n",
+		req, offset, ret);
+
+	return ret;
+}
+
+int
+mt7601u_vendor_request(struct mt7601u_dev *dev, const u8 req,
+		       const u8 direction, const u16 val, const u16 offset,
+		       void *buf, const size_t buflen)
+{
+	int ret;
+
+	mutex_lock(&dev->vendor_req_mutex);
+
+	ret = __mt7601u_vendor_request(dev, req, direction, val, offset,
+				       buf, buflen);
+	if (ret == -ENODEV)
+		set_bit(MT7601U_STATE_REMOVED, &dev->state);
+
+	mutex_unlock(&dev->vendor_req_mutex);
+
+	return ret;
+}
+
+void mt7601u_vendor_reset(struct mt7601u_dev *dev)
+{
+	mt7601u_vendor_request(dev, MT_VEND_DEV_MODE, USB_DIR_OUT,
+			       MT_VEND_DEV_MODE_RESET, 0, NULL, 0);
+}
+
+u32 mt7601u_rr(struct mt7601u_dev *dev, u32 offset)
+{
+	int ret;
+	__le32 reg;
+	u32 val;
+
+	WARN_ONCE(offset > USHRT_MAX, "read high off:%08x", offset);
+
+	ret = mt7601u_vendor_request(dev, MT_VEND_MULTI_READ, USB_DIR_IN,
+				     0, offset, &reg, sizeof(reg));
+	val = le32_to_cpu(reg);
+	if (ret > 0 && ret != sizeof(reg)) {
+		dev_err(dev->dev, "Error: wrong size read:%d off:%08x\n",
+			ret, offset);
+		val = ~0;
+	}
+
+	trace_reg_read(dev, offset, val);
+	return val;
+}
+
+int mt7601u_vendor_single_wr(struct mt7601u_dev *dev, const u8 req,
+			     const u16 offset, const u32 val)
+{
+	int ret;
+
+	ret = mt7601u_vendor_request(dev, req, USB_DIR_OUT,
+				     val & 0xffff, offset, NULL, 0);
+	if (ret)
+		return ret;
+	return mt7601u_vendor_request(dev, req, USB_DIR_OUT,
+				      val >> 16, offset + 2, NULL, 0);
+}
+
+void mt7601u_wr(struct mt7601u_dev *dev, u32 offset, u32 val)
+{
+	WARN_ONCE(offset > USHRT_MAX, "write high off:%08x", offset);
+
+	mt7601u_vendor_single_wr(dev, MT_VEND_WRITE, offset, val);
+	trace_reg_write(dev, offset, val);
+}
+
+u32 mt7601u_rmw(struct mt7601u_dev *dev, u32 offset, u32 mask, u32 val)
+{
+	val |= mt7601u_rr(dev, offset) & ~mask;
+	mt7601u_wr(dev, offset, val);
+	return val;
+}
+
+u32 mt7601u_rmc(struct mt7601u_dev *dev, u32 offset, u32 mask, u32 val)
+{
+	u32 reg = mt7601u_rr(dev, offset);
+
+	val |= reg & ~mask;
+	if (reg != val)
+		mt7601u_wr(dev, offset, val);
+	return val;
+}
+
+void mt7601u_wr_copy(struct mt7601u_dev *dev, u32 offset,
+		     const void *data, int len)
+{
+	WARN_ONCE(offset & 3, "unaligned write copy off:%08x", offset);
+	WARN_ONCE(len & 3, "short write copy off:%08x", offset);
+
+	mt7601u_burst_write_regs(dev, offset, data, len / 4);
+}
+
+void mt7601u_addr_wr(struct mt7601u_dev *dev, const u32 offset, const u8 *addr)
+{
+	mt7601u_wr(dev, offset, get_unaligned_le32(addr));
+	mt7601u_wr(dev, offset + 4, addr[4] | addr[5] << 8);
+}
+
+static int mt7601u_assign_pipes(struct usb_interface *usb_intf,
+				struct mt7601u_dev *dev)
+{
+	struct usb_endpoint_descriptor *ep_desc;
+	struct usb_host_interface *intf_desc = usb_intf->cur_altsetting;
+	unsigned i, ep_i = 0, ep_o = 0;
+
+	BUILD_BUG_ON(sizeof(dev->in_eps) < __MT_EP_IN_MAX);
+	BUILD_BUG_ON(sizeof(dev->out_eps) < __MT_EP_OUT_MAX);
+
+	for (i = 0; i < intf_desc->desc.bNumEndpoints; i++) {
+		ep_desc = &intf_desc->endpoint[i].desc;
+
+		if (usb_endpoint_is_bulk_in(ep_desc) &&
+		    ep_i++ < __MT_EP_IN_MAX) {
+			dev->in_eps[ep_i - 1] = usb_endpoint_num(ep_desc);
+			dev->in_max_packet = usb_endpoint_maxp(ep_desc);
+			/* Note: this is ignored by usb sub-system but vendor
+			 *	 code does it. We can drop this at some point.
+			 */
+			dev->in_eps[ep_i - 1] |= USB_DIR_IN;
+		} else if (usb_endpoint_is_bulk_out(ep_desc) &&
+			   ep_o++ < __MT_EP_OUT_MAX) {
+			dev->out_eps[ep_o - 1] = usb_endpoint_num(ep_desc);
+			dev->out_max_packet = usb_endpoint_maxp(ep_desc);
+		}
+	}
+
+	if (ep_i != __MT_EP_IN_MAX || ep_o != __MT_EP_OUT_MAX) {
+		dev_err(dev->dev, "Error: wrong pipe number in:%d out:%d\n",
+			ep_i, ep_o);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int mt7601u_probe(struct usb_interface *usb_intf,
+			 const struct usb_device_id *id)
+{
+	struct usb_device *usb_dev = interface_to_usbdev(usb_intf);
+	struct mt7601u_dev *dev;
+	u32 asic_rev, mac_rev;
+	int ret;
+
+	dev = mt7601u_alloc_device(&usb_intf->dev);
+	if (!dev)
+		return -ENOMEM;
+
+	usb_dev = usb_get_dev(usb_dev);
+	usb_reset_device(usb_dev);
+
+	usb_set_intfdata(usb_intf, dev);
+
+	ret = mt7601u_assign_pipes(usb_intf, dev);
+	if (ret)
+		goto err;
+	ret = mt7601u_wait_asic_ready(dev);
+	if (ret)
+		goto err;
+
+	asic_rev = mt7601u_rr(dev, MT_ASIC_VERSION);
+	mac_rev = mt7601u_rr(dev, MT_MAC_CSR0);
+	dev_info(dev->dev, "ASIC revision: %08x MAC revision: %08x\n",
+		 asic_rev, mac_rev);
+
+	/* Note: vendor driver skips this check for MT7601U */
+	if (!(mt7601u_rr(dev, MT_EFUSE_CTRL) & MT_EFUSE_CTRL_SEL))
+		dev_warn(dev->dev, "Warning: eFUSE not present\n");
+
+	ret = mt7601u_init_hardware(dev);
+	if (ret)
+		goto err;
+	ret = mt7601u_register_device(dev);
+	if (ret)
+		goto err_hw;
+
+	set_bit(MT7601U_STATE_INITIALIZED, &dev->state);
+
+	return 0;
+err_hw:
+	mt7601u_cleanup(dev);
+err:
+	usb_set_intfdata(usb_intf, NULL);
+	usb_put_dev(interface_to_usbdev(usb_intf));
+
+	destroy_workqueue(dev->stat_wq);
+	ieee80211_free_hw(dev->hw);
+	return ret;
+}
+
+static void mt7601u_disconnect(struct usb_interface *usb_intf)
+{
+	struct mt7601u_dev *dev = usb_get_intfdata(usb_intf);
+
+	ieee80211_unregister_hw(dev->hw);
+	mt7601u_cleanup(dev);
+
+	usb_set_intfdata(usb_intf, NULL);
+	usb_put_dev(interface_to_usbdev(usb_intf));
+
+	destroy_workqueue(dev->stat_wq);
+	ieee80211_free_hw(dev->hw);
+}
+
+static int mt7601u_suspend(struct usb_interface *usb_intf, pm_message_t state)
+{
+	struct mt7601u_dev *dev = usb_get_intfdata(usb_intf);
+
+	mt7601u_cleanup(dev);
+
+	return 0;
+}
+
+static int mt7601u_resume(struct usb_interface *usb_intf)
+{
+	struct mt7601u_dev *dev = usb_get_intfdata(usb_intf);
+
+	return mt7601u_init_hardware(dev);
+}
+
+MODULE_DEVICE_TABLE(usb, mt7601u_device_table);
+MODULE_FIRMWARE(MT7601U_FIRMWARE);
+MODULE_LICENSE("GPL");
+
+static struct usb_driver mt7601u_driver = {
+	.name		= KBUILD_MODNAME,
+	.id_table	= mt7601u_device_table,
+	.probe		= mt7601u_probe,
+	.disconnect	= mt7601u_disconnect,
+	.suspend	= mt7601u_suspend,
+	.resume		= mt7601u_resume,
+	.reset_resume	= mt7601u_resume,
+	.soft_unbind	= 1,
+	.disable_hub_initiated_lpm = 1,
+};
+module_usb_driver(mt7601u_driver);