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v6.8
  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (c) 2011-2017, The Linux Foundation
  4 */
  5
  6#include <linux/slab.h>
  7#include <linux/pm_runtime.h>
  8#include "slimbus.h"
  9
 10/**
 11 * slim_msg_response() - Deliver Message response received from a device to the
 12 *			framework.
 13 *
 14 * @ctrl: Controller handle
 15 * @reply: Reply received from the device
 16 * @len: Length of the reply
 17 * @tid: Transaction ID received with which framework can associate reply.
 18 *
 19 * Called by controller to inform framework about the response received.
 20 * This helps in making the API asynchronous, and controller-driver doesn't need
 21 * to manage 1 more table other than the one managed by framework mapping TID
 22 * with buffers
 23 */
 24void slim_msg_response(struct slim_controller *ctrl, u8 *reply, u8 tid, u8 len)
 25{
 26	struct slim_msg_txn *txn;
 27	struct slim_val_inf *msg;
 28	unsigned long flags;
 29
 30	spin_lock_irqsave(&ctrl->txn_lock, flags);
 31	txn = idr_find(&ctrl->tid_idr, tid);
 32	spin_unlock_irqrestore(&ctrl->txn_lock, flags);
 33
 34	if (txn == NULL)
 35		return;
 36
 37	msg = txn->msg;
 38	if (msg == NULL || msg->rbuf == NULL) {
 39		dev_err(ctrl->dev, "Got response to invalid TID:%d, len:%d\n",
 40				tid, len);
 41		return;
 42	}
 43
 44	slim_free_txn_tid(ctrl, txn);
 45	memcpy(msg->rbuf, reply, len);
 46	if (txn->comp)
 47		complete(txn->comp);
 48
 49	/* Remove runtime-pm vote now that response was received for TID txn */
 50	pm_runtime_mark_last_busy(ctrl->dev);
 51	pm_runtime_put_autosuspend(ctrl->dev);
 52}
 53EXPORT_SYMBOL_GPL(slim_msg_response);
 54
 55/**
 56 * slim_alloc_txn_tid() - Allocate a tid to txn
 57 *
 58 * @ctrl: Controller handle
 59 * @txn: transaction to be allocated with tid.
 60 *
 61 * Return: zero on success with valid txn->tid and error code on failures.
 62 */
 63int slim_alloc_txn_tid(struct slim_controller *ctrl, struct slim_msg_txn *txn)
 64{
 65	unsigned long flags;
 66	int ret = 0;
 67
 68	spin_lock_irqsave(&ctrl->txn_lock, flags);
 69	ret = idr_alloc_cyclic(&ctrl->tid_idr, txn, 1,
 70				SLIM_MAX_TIDS, GFP_ATOMIC);
 71	if (ret < 0) {
 72		spin_unlock_irqrestore(&ctrl->txn_lock, flags);
 73		return ret;
 74	}
 75	txn->tid = ret;
 76	spin_unlock_irqrestore(&ctrl->txn_lock, flags);
 77	return 0;
 78}
 79EXPORT_SYMBOL_GPL(slim_alloc_txn_tid);
 80
 81/**
 82 * slim_free_txn_tid() - Free tid of txn
 83 *
 84 * @ctrl: Controller handle
 85 * @txn: transaction whose tid should be freed
 86 */
 87void slim_free_txn_tid(struct slim_controller *ctrl, struct slim_msg_txn *txn)
 88{
 89	unsigned long flags;
 90
 91	spin_lock_irqsave(&ctrl->txn_lock, flags);
 92	idr_remove(&ctrl->tid_idr, txn->tid);
 93	spin_unlock_irqrestore(&ctrl->txn_lock, flags);
 94}
 95EXPORT_SYMBOL_GPL(slim_free_txn_tid);
 96
 97/**
 98 * slim_do_transfer() - Process a SLIMbus-messaging transaction
 99 *
100 * @ctrl: Controller handle
101 * @txn: Transaction to be sent over SLIMbus
102 *
103 * Called by controller to transmit messaging transactions not dealing with
104 * Interface/Value elements. (e.g. transmitting a message to assign logical
105 * address to a slave device
106 *
107 * Return: -ETIMEDOUT: If transmission of this message timed out
108 *	(e.g. due to bus lines not being clocked or driven by controller)
109 */
110int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn)
111{
112	DECLARE_COMPLETION_ONSTACK(done);
113	bool need_tid = false, clk_pause_msg = false;
114	int ret, timeout;
115
116	/*
117	 * do not vote for runtime-PM if the transactions are part of clock
118	 * pause sequence
119	 */
120	if (ctrl->sched.clk_state == SLIM_CLK_ENTERING_PAUSE &&
121		(txn->mt == SLIM_MSG_MT_CORE &&
122		 txn->mc >= SLIM_MSG_MC_BEGIN_RECONFIGURATION &&
123		 txn->mc <= SLIM_MSG_MC_RECONFIGURE_NOW))
124		clk_pause_msg = true;
125
126	if (!clk_pause_msg) {
127		ret = pm_runtime_get_sync(ctrl->dev);
128		if (ctrl->sched.clk_state != SLIM_CLK_ACTIVE) {
129			dev_err(ctrl->dev, "ctrl wrong state:%d, ret:%d\n",
130				ctrl->sched.clk_state, ret);
131			goto slim_xfer_err;
132		}
133	}
134	/* Initialize tid to invalid value */
135	txn->tid = 0;
136	need_tid = slim_tid_txn(txn->mt, txn->mc);
137
138	if (need_tid) {
139		ret = slim_alloc_txn_tid(ctrl, txn);
140		if (ret)
141			return ret;
142
143		if (!txn->msg->comp)
144			txn->comp = &done;
145		else
146			txn->comp = txn->comp;
147	}
148
149	ret = ctrl->xfer_msg(ctrl, txn);
150
151	if (!ret && need_tid && !txn->msg->comp) {
152		unsigned long ms = txn->rl + HZ;
153
154		timeout = wait_for_completion_timeout(txn->comp,
155						      msecs_to_jiffies(ms));
156		if (!timeout) {
157			ret = -ETIMEDOUT;
158			slim_free_txn_tid(ctrl, txn);
159		}
160	}
161
162	if (ret)
163		dev_err(ctrl->dev, "Tx:MT:0x%x, MC:0x%x, LA:0x%x failed:%d\n",
164			txn->mt, txn->mc, txn->la, ret);
165
166slim_xfer_err:
167	if (!clk_pause_msg && (txn->tid == 0  || ret == -ETIMEDOUT)) {
168		/*
169		 * remove runtime-pm vote if this was TX only, or
170		 * if there was error during this transaction
171		 */
172		pm_runtime_mark_last_busy(ctrl->dev);
173		pm_runtime_put_autosuspend(ctrl->dev);
174	}
175	return ret;
176}
177EXPORT_SYMBOL_GPL(slim_do_transfer);
178
179static int slim_val_inf_sanity(struct slim_controller *ctrl,
180			       struct slim_val_inf *msg, u8 mc)
181{
182	if (!msg || msg->num_bytes > 16 ||
183	    (msg->start_offset + msg->num_bytes) > 0xC00)
184		goto reterr;
185	switch (mc) {
186	case SLIM_MSG_MC_REQUEST_VALUE:
187	case SLIM_MSG_MC_REQUEST_INFORMATION:
188		if (msg->rbuf != NULL)
189			return 0;
190		break;
191
192	case SLIM_MSG_MC_CHANGE_VALUE:
193	case SLIM_MSG_MC_CLEAR_INFORMATION:
194		if (msg->wbuf != NULL)
195			return 0;
196		break;
197
198	case SLIM_MSG_MC_REQUEST_CHANGE_VALUE:
199	case SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION:
200		if (msg->rbuf != NULL && msg->wbuf != NULL)
201			return 0;
202		break;
203	}
204reterr:
205	if (msg)
206		dev_err(ctrl->dev, "Sanity check failed:msg:offset:0x%x, mc:%d\n",
207			msg->start_offset, mc);
208	return -EINVAL;
209}
210
211static u16 slim_slicesize(int code)
212{
213	static const u8 sizetocode[16] = {
214		0, 1, 2, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7
215	};
216
217	code = clamp(code, 1, (int)ARRAY_SIZE(sizetocode));
218
219	return sizetocode[code - 1];
220}
221
222/**
223 * slim_xfer_msg() - Transfer a value info message on slim device
224 *
225 * @sbdev: slim device to which this msg has to be transfered
226 * @msg: value info message pointer
227 * @mc: message code of the message
228 *
229 * Called by drivers which want to transfer a vlaue or info elements.
230 *
231 * Return: -ETIMEDOUT: If transmission of this message timed out
232 */
233int slim_xfer_msg(struct slim_device *sbdev, struct slim_val_inf *msg,
234		  u8 mc)
235{
236	DEFINE_SLIM_LDEST_TXN(txn_stack, mc, 6, sbdev->laddr, msg);
237	struct slim_msg_txn *txn = &txn_stack;
238	struct slim_controller *ctrl = sbdev->ctrl;
239	int ret;
240	u16 sl;
241
242	if (!ctrl)
243		return -EINVAL;
244
245	ret = slim_val_inf_sanity(ctrl, msg, mc);
246	if (ret)
247		return ret;
248
249	sl = slim_slicesize(msg->num_bytes);
250
251	dev_dbg(ctrl->dev, "SB xfer msg:os:%x, len:%d, MC:%x, sl:%x\n",
252		msg->start_offset, msg->num_bytes, mc, sl);
253
254	txn->ec = ((sl | (1 << 3)) | ((msg->start_offset & 0xFFF) << 4));
255
256	switch (mc) {
257	case SLIM_MSG_MC_REQUEST_CHANGE_VALUE:
258	case SLIM_MSG_MC_CHANGE_VALUE:
259	case SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION:
260	case SLIM_MSG_MC_CLEAR_INFORMATION:
261		txn->rl += msg->num_bytes;
262		break;
263	default:
264		break;
265	}
266
267	if (slim_tid_txn(txn->mt, txn->mc))
268		txn->rl++;
269
270	return slim_do_transfer(ctrl, txn);
271}
272EXPORT_SYMBOL_GPL(slim_xfer_msg);
273
274static void slim_fill_msg(struct slim_val_inf *msg, u32 addr,
275			 size_t count, u8 *rbuf, u8 *wbuf)
276{
277	msg->start_offset = addr;
278	msg->num_bytes = count;
279	msg->rbuf = rbuf;
280	msg->wbuf = wbuf;
281	msg->comp = NULL;
282}
283
284/**
285 * slim_read() - Read SLIMbus value element
286 *
287 * @sdev: client handle.
288 * @addr:  address of value element to read.
289 * @count: number of bytes to read. Maximum bytes allowed are 16.
290 * @val: will return what the value element value was
291 *
292 * Return: -EINVAL for Invalid parameters, -ETIMEDOUT If transmission of
293 * this message timed out (e.g. due to bus lines not being clocked
294 * or driven by controller)
295 */
296int slim_read(struct slim_device *sdev, u32 addr, size_t count, u8 *val)
297{
298	struct slim_val_inf msg;
299
300	slim_fill_msg(&msg, addr, count, val, NULL);
301
302	return slim_xfer_msg(sdev, &msg, SLIM_MSG_MC_REQUEST_VALUE);
303}
304EXPORT_SYMBOL_GPL(slim_read);
305
306/**
307 * slim_readb() - Read byte from SLIMbus value element
308 *
309 * @sdev: client handle.
310 * @addr:  address in the value element to read.
311 *
312 * Return: byte value of value element.
313 */
314int slim_readb(struct slim_device *sdev, u32 addr)
315{
316	int ret;
317	u8 buf;
318
319	ret = slim_read(sdev, addr, 1, &buf);
320	if (ret < 0)
321		return ret;
322	else
323		return buf;
324}
325EXPORT_SYMBOL_GPL(slim_readb);
326
327/**
328 * slim_write() - Write SLIMbus value element
329 *
330 * @sdev: client handle.
331 * @addr:  address in the value element to write.
332 * @count: number of bytes to write. Maximum bytes allowed are 16.
333 * @val: value to write to value element
334 *
335 * Return: -EINVAL for Invalid parameters, -ETIMEDOUT If transmission of
336 * this message timed out (e.g. due to bus lines not being clocked
337 * or driven by controller)
338 */
339int slim_write(struct slim_device *sdev, u32 addr, size_t count, u8 *val)
340{
341	struct slim_val_inf msg;
342
343	slim_fill_msg(&msg, addr, count,  NULL, val);
344
345	return slim_xfer_msg(sdev, &msg, SLIM_MSG_MC_CHANGE_VALUE);
346}
347EXPORT_SYMBOL_GPL(slim_write);
348
349/**
350 * slim_writeb() - Write byte to SLIMbus value element
351 *
352 * @sdev: client handle.
353 * @addr:  address of value element to write.
354 * @value: value to write to value element
355 *
356 * Return: -EINVAL for Invalid parameters, -ETIMEDOUT If transmission of
357 * this message timed out (e.g. due to bus lines not being clocked
358 * or driven by controller)
359 *
360 */
361int slim_writeb(struct slim_device *sdev, u32 addr, u8 value)
362{
363	return slim_write(sdev, addr, 1, &value);
364}
365EXPORT_SYMBOL_GPL(slim_writeb);
v5.9
  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (c) 2011-2017, The Linux Foundation
  4 */
  5
  6#include <linux/slab.h>
  7#include <linux/pm_runtime.h>
  8#include "slimbus.h"
  9
 10/**
 11 * slim_msg_response() - Deliver Message response received from a device to the
 12 *			framework.
 13 *
 14 * @ctrl: Controller handle
 15 * @reply: Reply received from the device
 16 * @len: Length of the reply
 17 * @tid: Transaction ID received with which framework can associate reply.
 18 *
 19 * Called by controller to inform framework about the response received.
 20 * This helps in making the API asynchronous, and controller-driver doesn't need
 21 * to manage 1 more table other than the one managed by framework mapping TID
 22 * with buffers
 23 */
 24void slim_msg_response(struct slim_controller *ctrl, u8 *reply, u8 tid, u8 len)
 25{
 26	struct slim_msg_txn *txn;
 27	struct slim_val_inf *msg;
 28	unsigned long flags;
 29
 30	spin_lock_irqsave(&ctrl->txn_lock, flags);
 31	txn = idr_find(&ctrl->tid_idr, tid);
 32	spin_unlock_irqrestore(&ctrl->txn_lock, flags);
 33
 34	if (txn == NULL)
 35		return;
 36
 37	msg = txn->msg;
 38	if (msg == NULL || msg->rbuf == NULL) {
 39		dev_err(ctrl->dev, "Got response to invalid TID:%d, len:%d\n",
 40				tid, len);
 41		return;
 42	}
 43
 44	slim_free_txn_tid(ctrl, txn);
 45	memcpy(msg->rbuf, reply, len);
 46	if (txn->comp)
 47		complete(txn->comp);
 48
 49	/* Remove runtime-pm vote now that response was received for TID txn */
 50	pm_runtime_mark_last_busy(ctrl->dev);
 51	pm_runtime_put_autosuspend(ctrl->dev);
 52}
 53EXPORT_SYMBOL_GPL(slim_msg_response);
 54
 55/**
 56 * slim_alloc_txn_tid() - Allocate a tid to txn
 57 *
 58 * @ctrl: Controller handle
 59 * @txn: transaction to be allocated with tid.
 60 *
 61 * Return: zero on success with valid txn->tid and error code on failures.
 62 */
 63int slim_alloc_txn_tid(struct slim_controller *ctrl, struct slim_msg_txn *txn)
 64{
 65	unsigned long flags;
 66	int ret = 0;
 67
 68	spin_lock_irqsave(&ctrl->txn_lock, flags);
 69	ret = idr_alloc_cyclic(&ctrl->tid_idr, txn, 0,
 70				SLIM_MAX_TIDS, GFP_ATOMIC);
 71	if (ret < 0) {
 72		spin_unlock_irqrestore(&ctrl->txn_lock, flags);
 73		return ret;
 74	}
 75	txn->tid = ret;
 76	spin_unlock_irqrestore(&ctrl->txn_lock, flags);
 77	return 0;
 78}
 79EXPORT_SYMBOL_GPL(slim_alloc_txn_tid);
 80
 81/**
 82 * slim_free_txn_tid() - Freee tid of txn
 83 *
 84 * @ctrl: Controller handle
 85 * @txn: transaction whose tid should be freed
 86 */
 87void slim_free_txn_tid(struct slim_controller *ctrl, struct slim_msg_txn *txn)
 88{
 89	unsigned long flags;
 90
 91	spin_lock_irqsave(&ctrl->txn_lock, flags);
 92	idr_remove(&ctrl->tid_idr, txn->tid);
 93	spin_unlock_irqrestore(&ctrl->txn_lock, flags);
 94}
 95EXPORT_SYMBOL_GPL(slim_free_txn_tid);
 96
 97/**
 98 * slim_do_transfer() - Process a SLIMbus-messaging transaction
 99 *
100 * @ctrl: Controller handle
101 * @txn: Transaction to be sent over SLIMbus
102 *
103 * Called by controller to transmit messaging transactions not dealing with
104 * Interface/Value elements. (e.g. transmittting a message to assign logical
105 * address to a slave device
106 *
107 * Return: -ETIMEDOUT: If transmission of this message timed out
108 *	(e.g. due to bus lines not being clocked or driven by controller)
109 */
110int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn)
111{
112	DECLARE_COMPLETION_ONSTACK(done);
113	bool need_tid = false, clk_pause_msg = false;
114	int ret, timeout;
115
116	/*
117	 * do not vote for runtime-PM if the transactions are part of clock
118	 * pause sequence
119	 */
120	if (ctrl->sched.clk_state == SLIM_CLK_ENTERING_PAUSE &&
121		(txn->mt == SLIM_MSG_MT_CORE &&
122		 txn->mc >= SLIM_MSG_MC_BEGIN_RECONFIGURATION &&
123		 txn->mc <= SLIM_MSG_MC_RECONFIGURE_NOW))
124		clk_pause_msg = true;
125
126	if (!clk_pause_msg) {
127		ret = pm_runtime_get_sync(ctrl->dev);
128		if (ctrl->sched.clk_state != SLIM_CLK_ACTIVE) {
129			dev_err(ctrl->dev, "ctrl wrong state:%d, ret:%d\n",
130				ctrl->sched.clk_state, ret);
131			goto slim_xfer_err;
132		}
133	}
134
 
135	need_tid = slim_tid_txn(txn->mt, txn->mc);
136
137	if (need_tid) {
138		ret = slim_alloc_txn_tid(ctrl, txn);
139		if (ret)
140			return ret;
141
142		if (!txn->msg->comp)
143			txn->comp = &done;
144		else
145			txn->comp = txn->comp;
146	}
147
148	ret = ctrl->xfer_msg(ctrl, txn);
149
150	if (!ret && need_tid && !txn->msg->comp) {
151		unsigned long ms = txn->rl + HZ;
152
153		timeout = wait_for_completion_timeout(txn->comp,
154						      msecs_to_jiffies(ms));
155		if (!timeout) {
156			ret = -ETIMEDOUT;
157			slim_free_txn_tid(ctrl, txn);
158		}
159	}
160
161	if (ret)
162		dev_err(ctrl->dev, "Tx:MT:0x%x, MC:0x%x, LA:0x%x failed:%d\n",
163			txn->mt, txn->mc, txn->la, ret);
164
165slim_xfer_err:
166	if (!clk_pause_msg && (!need_tid  || ret == -ETIMEDOUT)) {
167		/*
168		 * remove runtime-pm vote if this was TX only, or
169		 * if there was error during this transaction
170		 */
171		pm_runtime_mark_last_busy(ctrl->dev);
172		pm_runtime_put_autosuspend(ctrl->dev);
173	}
174	return ret;
175}
176EXPORT_SYMBOL_GPL(slim_do_transfer);
177
178static int slim_val_inf_sanity(struct slim_controller *ctrl,
179			       struct slim_val_inf *msg, u8 mc)
180{
181	if (!msg || msg->num_bytes > 16 ||
182	    (msg->start_offset + msg->num_bytes) > 0xC00)
183		goto reterr;
184	switch (mc) {
185	case SLIM_MSG_MC_REQUEST_VALUE:
186	case SLIM_MSG_MC_REQUEST_INFORMATION:
187		if (msg->rbuf != NULL)
188			return 0;
189		break;
190
191	case SLIM_MSG_MC_CHANGE_VALUE:
192	case SLIM_MSG_MC_CLEAR_INFORMATION:
193		if (msg->wbuf != NULL)
194			return 0;
195		break;
196
197	case SLIM_MSG_MC_REQUEST_CHANGE_VALUE:
198	case SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION:
199		if (msg->rbuf != NULL && msg->wbuf != NULL)
200			return 0;
201		break;
202	}
203reterr:
204	if (msg)
205		dev_err(ctrl->dev, "Sanity check failed:msg:offset:0x%x, mc:%d\n",
206			msg->start_offset, mc);
207	return -EINVAL;
208}
209
210static u16 slim_slicesize(int code)
211{
212	static const u8 sizetocode[16] = {
213		0, 1, 2, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7
214	};
215
216	code = clamp(code, 1, (int)ARRAY_SIZE(sizetocode));
217
218	return sizetocode[code - 1];
219}
220
221/**
222 * slim_xfer_msg() - Transfer a value info message on slim device
223 *
224 * @sbdev: slim device to which this msg has to be transfered
225 * @msg: value info message pointer
226 * @mc: message code of the message
227 *
228 * Called by drivers which want to transfer a vlaue or info elements.
229 *
230 * Return: -ETIMEDOUT: If transmission of this message timed out
231 */
232int slim_xfer_msg(struct slim_device *sbdev, struct slim_val_inf *msg,
233		  u8 mc)
234{
235	DEFINE_SLIM_LDEST_TXN(txn_stack, mc, 6, sbdev->laddr, msg);
236	struct slim_msg_txn *txn = &txn_stack;
237	struct slim_controller *ctrl = sbdev->ctrl;
238	int ret;
239	u16 sl;
240
241	if (!ctrl)
242		return -EINVAL;
243
244	ret = slim_val_inf_sanity(ctrl, msg, mc);
245	if (ret)
246		return ret;
247
248	sl = slim_slicesize(msg->num_bytes);
249
250	dev_dbg(ctrl->dev, "SB xfer msg:os:%x, len:%d, MC:%x, sl:%x\n",
251		msg->start_offset, msg->num_bytes, mc, sl);
252
253	txn->ec = ((sl | (1 << 3)) | ((msg->start_offset & 0xFFF) << 4));
254
255	switch (mc) {
256	case SLIM_MSG_MC_REQUEST_CHANGE_VALUE:
257	case SLIM_MSG_MC_CHANGE_VALUE:
258	case SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION:
259	case SLIM_MSG_MC_CLEAR_INFORMATION:
260		txn->rl += msg->num_bytes;
 
261	default:
262		break;
263	}
264
265	if (slim_tid_txn(txn->mt, txn->mc))
266		txn->rl++;
267
268	return slim_do_transfer(ctrl, txn);
269}
270EXPORT_SYMBOL_GPL(slim_xfer_msg);
271
272static void slim_fill_msg(struct slim_val_inf *msg, u32 addr,
273			 size_t count, u8 *rbuf, u8 *wbuf)
274{
275	msg->start_offset = addr;
276	msg->num_bytes = count;
277	msg->rbuf = rbuf;
278	msg->wbuf = wbuf;
279	msg->comp = NULL;
280}
281
282/**
283 * slim_read() - Read SLIMbus value element
284 *
285 * @sdev: client handle.
286 * @addr:  address of value element to read.
287 * @count: number of bytes to read. Maximum bytes allowed are 16.
288 * @val: will return what the value element value was
289 *
290 * Return: -EINVAL for Invalid parameters, -ETIMEDOUT If transmission of
291 * this message timed out (e.g. due to bus lines not being clocked
292 * or driven by controller)
293 */
294int slim_read(struct slim_device *sdev, u32 addr, size_t count, u8 *val)
295{
296	struct slim_val_inf msg;
297
298	slim_fill_msg(&msg, addr, count, val, NULL);
299
300	return slim_xfer_msg(sdev, &msg, SLIM_MSG_MC_REQUEST_VALUE);
301}
302EXPORT_SYMBOL_GPL(slim_read);
303
304/**
305 * slim_readb() - Read byte from SLIMbus value element
306 *
307 * @sdev: client handle.
308 * @addr:  address in the value element to read.
309 *
310 * Return: byte value of value element.
311 */
312int slim_readb(struct slim_device *sdev, u32 addr)
313{
314	int ret;
315	u8 buf;
316
317	ret = slim_read(sdev, addr, 1, &buf);
318	if (ret < 0)
319		return ret;
320	else
321		return buf;
322}
323EXPORT_SYMBOL_GPL(slim_readb);
324
325/**
326 * slim_write() - Write SLIMbus value element
327 *
328 * @sdev: client handle.
329 * @addr:  address in the value element to write.
330 * @count: number of bytes to write. Maximum bytes allowed are 16.
331 * @val: value to write to value element
332 *
333 * Return: -EINVAL for Invalid parameters, -ETIMEDOUT If transmission of
334 * this message timed out (e.g. due to bus lines not being clocked
335 * or driven by controller)
336 */
337int slim_write(struct slim_device *sdev, u32 addr, size_t count, u8 *val)
338{
339	struct slim_val_inf msg;
340
341	slim_fill_msg(&msg, addr, count,  NULL, val);
342
343	return slim_xfer_msg(sdev, &msg, SLIM_MSG_MC_CHANGE_VALUE);
344}
345EXPORT_SYMBOL_GPL(slim_write);
346
347/**
348 * slim_writeb() - Write byte to SLIMbus value element
349 *
350 * @sdev: client handle.
351 * @addr:  address of value element to write.
352 * @value: value to write to value element
353 *
354 * Return: -EINVAL for Invalid parameters, -ETIMEDOUT If transmission of
355 * this message timed out (e.g. due to bus lines not being clocked
356 * or driven by controller)
357 *
358 */
359int slim_writeb(struct slim_device *sdev, u32 addr, u8 value)
360{
361	return slim_write(sdev, addr, 1, &value);
362}
363EXPORT_SYMBOL_GPL(slim_writeb);