staging: wfx: allow to send commands to chip

Chip has multiple input buffers and can handle multiple 802.11 frames
in parallel. However, other HIF command must be sent sequentially.
wsm_send_cmd() handles these requests.

This commit also add send_hif_cmd in debugfs. This file allows to send
arbitrary commands to chip. It can be used for debug and testing.

Signed-off-by: Jérôme Pouiller <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/wfx/Makefile

···
 	bh.o \
 	hwio.o \
 	fwio.o \
+	hif_tx.o \
 	hif_rx.o \
 	main.o \
 	sta.o \

drivers/staging/wfx/bh.c

···
 	for (i = 0; i < max_msg; i++) {
 		hif = NULL;
 		if (wdev->hif.tx_buffers_used < wdev->hw_caps.num_inp_ch_bufs) {
-			/* FIXME: get queued data */
+			if (try_wait_for_completion(&wdev->hif_cmd.ready)) {
+				WARN(!mutex_is_locked(&wdev->hif_cmd.lock), "data locking error");
+				hif = wdev->hif_cmd.buf_send;
+			}
 		}
 		if (!hif)
 			return i;

drivers/staging/wfx/debug.c

···
  */
 #include <linux/debugfs.h>
 
+#include "debug.h"
 #include "wfx.h"
 
 #define CREATE_TRACE_POINTS
 #include "traces.h"
+
+static const struct trace_print_flags hif_msg_print_map[] = {
+	hif_msg_list,
+};
+
+static const struct trace_print_flags hif_mib_print_map[] = {
+	hif_mib_list,
+};
+
+static const struct trace_print_flags wfx_reg_print_map[] = {
+	wfx_reg_list,
+};
+
+static const char *get_symbol(unsigned long val,
+		const struct trace_print_flags *symbol_array)
+{
+	int i;
+
+	for (i = 0; symbol_array[i].mask != -1; i++) {
+		if (val == symbol_array[i].mask)
+			return symbol_array[i].name;
+	}
+
+	return "unknown";
+}
+
+const char *get_hif_name(unsigned long id)
+{
+	return get_symbol(id, hif_msg_print_map);
+}
+
+const char *get_mib_name(unsigned long id)
+{
+	return get_symbol(id, hif_mib_print_map);
+}
+
+const char *get_reg_name(unsigned long id)
+{
+	return get_symbol(id, wfx_reg_print_map);
+}
+
+struct dbgfs_hif_msg {
+	struct wfx_dev *wdev;
+	struct completion complete;
+	u8 reply[1024];
+	int ret;
+};
+
+static ssize_t wfx_send_hif_msg_write(struct file *file, const char __user *user_buf,
+				      size_t count, loff_t *ppos)
+{
+	struct dbgfs_hif_msg *context = file->private_data;
+	struct wfx_dev *wdev = context->wdev;
+	struct hif_msg *request;
+
+	if (completion_done(&context->complete)) {
+		dev_dbg(wdev->dev, "read previous result before start a new one\n");
+		return -EBUSY;
+	}
+	if (count < sizeof(struct hif_msg))
+		return -EINVAL;
+
+	// wfx_cmd_send() chekc that reply buffer is wide enough, but do not
+	// return precise length read. User have to know how many bytes should
+	// be read. Filling reply buffer with a memory pattern may help user.
+	memset(context->reply, sizeof(context->reply), 0xFF);
+	request = memdup_user(user_buf, count);
+	if (IS_ERR(request))
+		return PTR_ERR(request);
+	if (request->len != count) {
+		kfree(request);
+		return -EINVAL;
+	}
+	context->ret = wfx_cmd_send(wdev, request, context->reply, sizeof(context->reply), false);
+
+	kfree(request);
+	complete(&context->complete);
+	return count;
+}
+
+static ssize_t wfx_send_hif_msg_read(struct file *file, char __user *user_buf,
+				     size_t count, loff_t *ppos)
+{
+	struct dbgfs_hif_msg *context = file->private_data;
+	int ret;
+
+	if (count > sizeof(context->reply))
+		return -EINVAL;
+	ret = wait_for_completion_interruptible(&context->complete);
+	if (ret)
+		return ret;
+	if (context->ret < 0)
+		return context->ret;
+	// Be carefull, write() is waiting for a full message while read()
+	// only return a payload
+	ret = copy_to_user(user_buf, context->reply, count);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static int wfx_send_hif_msg_open(struct inode *inode, struct file *file)
+{
+	struct dbgfs_hif_msg *context = kzalloc(sizeof(*context), GFP_KERNEL);
+
+	if (!context)
+		return -ENOMEM;
+	context->wdev = inode->i_private;
+	init_completion(&context->complete);
+	file->private_data = context;
+	return 0;
+}
+
+static int wfx_send_hif_msg_release(struct inode *inode, struct file *file)
+{
+	struct dbgfs_hif_msg *context = file->private_data;
+
+	kfree(context);
+	return 0;
+}
+
+static const struct file_operations wfx_send_hif_msg_fops = {
+	.open = wfx_send_hif_msg_open,
+	.release = wfx_send_hif_msg_release,
+	.write = wfx_send_hif_msg_write,
+	.read = wfx_send_hif_msg_read,
+};
 
 int wfx_debug_init(struct wfx_dev *wdev)
 {
 	struct dentry *d;
 
 	d = debugfs_create_dir("wfx", wdev->hw->wiphy->debugfsdir);
+	debugfs_create_file("send_hif_msg", 0600, d, wdev, &wfx_send_hif_msg_fops);
 
 	return 0;
 }

drivers/staging/wfx/debug.h

···
 
 int wfx_debug_init(struct wfx_dev *wdev);
 
+const char *get_hif_name(unsigned long id);
+const char *get_mib_name(unsigned long id);
+const char *get_reg_name(unsigned long id);
+
 #endif /* WFX_DEBUG_H */

drivers/staging/wfx/hif_rx.c

···
 #include "wfx.h"
 #include "hif_api_cmd.h"
 
+static int hif_generic_confirm(struct wfx_dev *wdev, struct hif_msg *hif, void *buf)
+{
+	// All confirm messages start with status
+	int status = le32_to_cpu(*((__le32 *) buf));
+	int cmd = hif->id;
+	int len = hif->len - 4; // drop header
+
+	WARN(!mutex_is_locked(&wdev->hif_cmd.lock), "data locking error");
+
+	if (!wdev->hif_cmd.buf_send) {
+		dev_warn(wdev->dev, "unexpected confirmation: 0x%.2x\n", cmd);
+		return -EINVAL;
+	}
+
+	if (cmd != wdev->hif_cmd.buf_send->id) {
+		dev_warn(wdev->dev, "chip response mismatch request: 0x%.2x vs 0x%.2x\n",
+			 cmd, wdev->hif_cmd.buf_send->id);
+		return -EINVAL;
+	}
+
+	if (wdev->hif_cmd.buf_recv) {
+		if (wdev->hif_cmd.len_recv >= len)
+			memcpy(wdev->hif_cmd.buf_recv, buf, len);
+		else
+			status = -ENOMEM;
+	}
+	wdev->hif_cmd.ret = status;
+
+	if (!wdev->hif_cmd.async) {
+		complete(&wdev->hif_cmd.done);
+	} else {
+		wdev->hif_cmd.buf_send = NULL;
+		mutex_unlock(&wdev->hif_cmd.lock);
+	}
+	return status;
+}
+
 static int hif_startup_indication(struct wfx_dev *wdev, struct hif_msg *hif, void *buf)
 {
 	struct hif_ind_startup *body = buf;
···
 	struct hif_msg *hif = (struct hif_msg *) skb->data;
 	int hif_id = hif->id;
 
+	// Note: mutex_is_lock cause an implicit memory barrier that protect
+	// buf_send
+	if (mutex_is_locked(&wdev->hif_cmd.lock)
+	    && wdev->hif_cmd.buf_send
+	    && wdev->hif_cmd.buf_send->id == hif_id) {
+		hif_generic_confirm(wdev, hif, hif->body);
+		goto free;
+	}
 	for (i = 0; i < ARRAY_SIZE(hif_handlers); i++) {
 		if (hif_handlers[i].msg_id == hif_id) {
 			if (hif_handlers[i].handler)

drivers/staging/wfx/hif_tx.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Implementation of host-to-chip commands (aka request/confirmation) of WFxxx
+ * Split Mac (WSM) API.
+ *
+ * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
+ * Copyright (c) 2010, ST-Ericsson
+ */
+#include <linux/skbuff.h>
+#include <linux/etherdevice.h>
+
+#include "hif_tx.h"
+#include "wfx.h"
+#include "bh.h"
+#include "debug.h"
+
+void wfx_init_hif_cmd(struct wfx_hif_cmd *hif_cmd)
+{
+	init_completion(&hif_cmd->ready);
+	init_completion(&hif_cmd->done);
+	mutex_init(&hif_cmd->lock);
+}
+
+int wfx_cmd_send(struct wfx_dev *wdev, struct hif_msg *request, void *reply, size_t reply_len, bool async)
+{
+	const char *mib_name = "";
+	const char *mib_sep = "";
+	int cmd = request->id;
+	int vif = request->interface;
+	int ret;
+
+	WARN(wdev->hif_cmd.buf_recv && wdev->hif_cmd.async, "API usage error");
+
+	// Do not wait for any reply if chip is frozen
+	if (wdev->chip_frozen)
+		return -ETIMEDOUT;
+
+	mutex_lock(&wdev->hif_cmd.lock);
+	WARN(wdev->hif_cmd.buf_send, "data locking error");
+
+	// Note: call to complete() below has an implicit memory barrier that
+	// hopefully protect buf_send
+	wdev->hif_cmd.buf_send = request;
+	wdev->hif_cmd.buf_recv = reply;
+	wdev->hif_cmd.len_recv = reply_len;
+	wdev->hif_cmd.async = async;
+	complete(&wdev->hif_cmd.ready);
+
+	wfx_bh_request_tx(wdev);
+
+	// NOTE: no timeout is catched async is enabled
+	if (async)
+		return 0;
+
+	ret = wait_for_completion_timeout(&wdev->hif_cmd.done, 1 * HZ);
+	if (!ret) {
+		dev_err(wdev->dev, "chip is abnormally long to answer\n");
+		reinit_completion(&wdev->hif_cmd.ready);
+		ret = wait_for_completion_timeout(&wdev->hif_cmd.done, 3 * HZ);
+	}
+	if (!ret) {
+		dev_err(wdev->dev, "chip did not answer\n");
+		wdev->chip_frozen = 1;
+		reinit_completion(&wdev->hif_cmd.done);
+		ret = -ETIMEDOUT;
+	} else {
+		ret = wdev->hif_cmd.ret;
+	}
+
+	wdev->hif_cmd.buf_send = NULL;
+	mutex_unlock(&wdev->hif_cmd.lock);
+
+	if (ret && (cmd == HIF_REQ_ID_READ_MIB || cmd == HIF_REQ_ID_WRITE_MIB)) {
+		mib_name = get_mib_name(((u16 *) request)[2]);
+		mib_sep = "/";
+	}
+	if (ret < 0)
+		dev_err(wdev->dev,
+			"WSM request %s%s%s (%#.2x) on vif %d returned error %d\n",
+			get_hif_name(cmd), mib_sep, mib_name, cmd, vif, ret);
+	if (ret > 0)
+		dev_warn(wdev->dev,
+			 "WSM request %s%s%s (%#.2x) on vif %d returned status %d\n",
+			 get_hif_name(cmd), mib_sep, mib_name, cmd, vif, ret);
+
+	return ret;
+}

drivers/staging/wfx/hif_tx.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Implementation of host-to-chip commands (aka request/confirmation) of WFxxx
+ * Split Mac (WSM) API.
+ *
+ * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
+ * Copyright (c) 2010, ST-Ericsson
+ * Copyright (C) 2010, ST-Ericsson SA
+ */
+#ifndef WFX_HIF_TX_H
+#define WFX_HIF_TX_H
+
+#include "hif_api_cmd.h"
+
+struct wfx_dev;
+struct wfx_vif;
+
+struct wfx_hif_cmd {
+	struct mutex      lock;
+	struct completion ready;
+	struct completion done;
+	bool              async;
+	struct hif_msg    *buf_send;
+	void              *buf_recv;
+	size_t            len_recv;
+	int               ret;
+};
+
+void wfx_init_hif_cmd(struct wfx_hif_cmd *wfx_hif_cmd);
+int wfx_cmd_send(struct wfx_dev *wdev, struct hif_msg *request,
+		 void *reply, size_t reply_len, bool async);
+
+#endif

drivers/staging/wfx/main.c

···
 	memcpy(&wdev->pdata, pdata, sizeof(*pdata));
 
 	init_completion(&wdev->firmware_ready);
+	wfx_init_hif_cmd(&wdev->hif_cmd);
 
 	return wdev;
 }

drivers/staging/wfx/wfx.h

···
 
 #include "bh.h"
 #include "main.h"
+#include "hif_tx.h"
 #include "hif_api_general.h"
 
 struct hwbus_ops;
···
 	struct completion	firmware_ready;
 	struct hif_ind_startup	hw_caps;
 	struct wfx_hif		hif;
+	int			chip_frozen;
+
+	struct wfx_hif_cmd	hif_cmd;
 };
 
 struct wfx_vif {