1// SPDX-License-Identifier: GPL-2.0
2/* Copyright(c) 2009 - 2018 Intel Corporation. */
3
4#include <linux/bitfield.h>
5#include "mbx.h"
6
7/**
8 *  e1000_poll_for_msg - Wait for message notification
9 *  @hw: pointer to the HW structure
10 *
11 *  returns SUCCESS if it successfully received a message notification
12 **/
13static s32 e1000_poll_for_msg(struct e1000_hw *hw)
14{
15	struct e1000_mbx_info *mbx = &hw->mbx;
16	int countdown = mbx->timeout;
17
18	if (!mbx->ops.check_for_msg)
19		goto out;
20
21	while (countdown && mbx->ops.check_for_msg(hw)) {
22		countdown--;
23		udelay(mbx->usec_delay);
24	}
25
26	/* if we failed, all future posted messages fail until reset */
27	if (!countdown)
28		mbx->timeout = 0;
29out:
30	return countdown ? E1000_SUCCESS : -E1000_ERR_MBX;
31}
32
33/**
34 *  e1000_poll_for_ack - Wait for message acknowledgment
35 *  @hw: pointer to the HW structure
36 *
37 *  returns SUCCESS if it successfully received a message acknowledgment
38 **/
39static s32 e1000_poll_for_ack(struct e1000_hw *hw)
40{
41	struct e1000_mbx_info *mbx = &hw->mbx;
42	int countdown = mbx->timeout;
43
44	if (!mbx->ops.check_for_ack)
45		goto out;
46
47	while (countdown && mbx->ops.check_for_ack(hw)) {
48		countdown--;
49		udelay(mbx->usec_delay);
50	}
51
52	/* if we failed, all future posted messages fail until reset */
53	if (!countdown)
54		mbx->timeout = 0;
55out:
56	return countdown ? E1000_SUCCESS : -E1000_ERR_MBX;
57}
58
59/**
60 *  e1000_read_posted_mbx - Wait for message notification and receive message
61 *  @hw: pointer to the HW structure
62 *  @msg: The message buffer
63 *  @size: Length of buffer
64 *
65 *  returns SUCCESS if it successfully received a message notification and
66 *  copied it into the receive buffer.
67 **/
68static s32 e1000_read_posted_mbx(struct e1000_hw *hw, u32 *msg, u16 size)
69{
70	struct e1000_mbx_info *mbx = &hw->mbx;
71	s32 ret_val = -E1000_ERR_MBX;
72
73	if (!mbx->ops.read)
74		goto out;
75
76	ret_val = e1000_poll_for_msg(hw);
77
78	/* if ack received read message, otherwise we timed out */
79	if (!ret_val)
80		ret_val = mbx->ops.read(hw, msg, size);
81out:
82	return ret_val;
83}
84
85/**
86 *  e1000_write_posted_mbx - Write a message to the mailbox, wait for ack
87 *  @hw: pointer to the HW structure
88 *  @msg: The message buffer
89 *  @size: Length of buffer
90 *
91 *  returns SUCCESS if it successfully copied message into the buffer and
92 *  received an ack to that message within delay * timeout period
93 **/
94static s32 e1000_write_posted_mbx(struct e1000_hw *hw, u32 *msg, u16 size)
95{
96	struct e1000_mbx_info *mbx = &hw->mbx;
97	s32 ret_val = -E1000_ERR_MBX;
98
99	/* exit if we either can't write or there isn't a defined timeout */
100	if (!mbx->ops.write || !mbx->timeout)
101		goto out;
102
103	/* send msg*/
104	ret_val = mbx->ops.write(hw, msg, size);
105
106	/* if msg sent wait until we receive an ack */
107	if (!ret_val)
108		ret_val = e1000_poll_for_ack(hw);
109out:
110	return ret_val;
111}
112
113/**
114 *  e1000_read_v2p_mailbox - read v2p mailbox
115 *  @hw: pointer to the HW structure
116 *
117 *  This function is used to read the v2p mailbox without losing the read to
118 *  clear status bits.
119 **/
120static u32 e1000_read_v2p_mailbox(struct e1000_hw *hw)
121{
122	u32 v2p_mailbox = er32(V2PMAILBOX(0));
123
124	v2p_mailbox |= hw->dev_spec.vf.v2p_mailbox;
125	hw->dev_spec.vf.v2p_mailbox |= v2p_mailbox & E1000_V2PMAILBOX_R2C_BITS;
126
127	return v2p_mailbox;
128}
129
130/**
131 *  e1000_check_for_bit_vf - Determine if a status bit was set
132 *  @hw: pointer to the HW structure
133 *  @mask: bitmask for bits to be tested and cleared
134 *
135 *  This function is used to check for the read to clear bits within
136 *  the V2P mailbox.
137 **/
138static s32 e1000_check_for_bit_vf(struct e1000_hw *hw, u32 mask)
139{
140	u32 v2p_mailbox = e1000_read_v2p_mailbox(hw);
141	s32 ret_val = -E1000_ERR_MBX;
142
143	if (v2p_mailbox & mask)
144		ret_val = E1000_SUCCESS;
145
146	hw->dev_spec.vf.v2p_mailbox &= ~mask;
147
148	return ret_val;
149}
150
151/**
152 *  e1000_check_for_msg_vf - checks to see if the PF has sent mail
153 *  @hw: pointer to the HW structure
154 *
155 *  returns SUCCESS if the PF has set the Status bit or else ERR_MBX
156 **/
157static s32 e1000_check_for_msg_vf(struct e1000_hw *hw)
158{
159	s32 ret_val = -E1000_ERR_MBX;
160
161	if (!e1000_check_for_bit_vf(hw, E1000_V2PMAILBOX_PFSTS)) {
162		ret_val = E1000_SUCCESS;
163		hw->mbx.stats.reqs++;
164	}
165
166	return ret_val;
167}
168
169/**
170 *  e1000_check_for_ack_vf - checks to see if the PF has ACK'd
171 *  @hw: pointer to the HW structure
172 *
173 *  returns SUCCESS if the PF has set the ACK bit or else ERR_MBX
174 **/
175static s32 e1000_check_for_ack_vf(struct e1000_hw *hw)
176{
177	s32 ret_val = -E1000_ERR_MBX;
178
179	if (!e1000_check_for_bit_vf(hw, E1000_V2PMAILBOX_PFACK)) {
180		ret_val = E1000_SUCCESS;
181		hw->mbx.stats.acks++;
182	}
183
184	return ret_val;
185}
186
187/**
188 *  e1000_check_for_rst_vf - checks to see if the PF has reset
189 *  @hw: pointer to the HW structure
190 *
191 *  returns true if the PF has set the reset done bit or else false
192 **/
193static s32 e1000_check_for_rst_vf(struct e1000_hw *hw)
194{
195	s32 ret_val = -E1000_ERR_MBX;
196
197	if (!e1000_check_for_bit_vf(hw, (E1000_V2PMAILBOX_RSTD |
198					 E1000_V2PMAILBOX_RSTI))) {
199		ret_val = E1000_SUCCESS;
200		hw->mbx.stats.rsts++;
201	}
202
203	return ret_val;
204}
205
206/**
207 *  e1000_obtain_mbx_lock_vf - obtain mailbox lock
208 *  @hw: pointer to the HW structure
209 *
210 *  return SUCCESS if we obtained the mailbox lock
211 **/
212static s32 e1000_obtain_mbx_lock_vf(struct e1000_hw *hw)
213{
214	s32 ret_val = -E1000_ERR_MBX;
215	int count = 10;
216
217	do {
218		/* Take ownership of the buffer */
219		ew32(V2PMAILBOX(0), E1000_V2PMAILBOX_VFU);
220
221		/* reserve mailbox for VF use */
222		if (e1000_read_v2p_mailbox(hw) & E1000_V2PMAILBOX_VFU) {
223			ret_val = 0;
224			break;
225		}
226		udelay(1000);
227	} while (count-- > 0);
228
229	return ret_val;
230}
231
232/**
233 *  e1000_write_mbx_vf - Write a message to the mailbox
234 *  @hw: pointer to the HW structure
235 *  @msg: The message buffer
236 *  @size: Length of buffer
237 *
238 *  returns SUCCESS if it successfully copied message into the buffer
239 **/
240static s32 e1000_write_mbx_vf(struct e1000_hw *hw, u32 *msg, u16 size)
241{
242	s32 err;
243	u16 i;
244
245	lockdep_assert_held(&hw->mbx_lock);
246
247	/* lock the mailbox to prevent pf/vf race condition */
248	err = e1000_obtain_mbx_lock_vf(hw);
249	if (err)
250		goto out_no_write;
251
252	/* flush any ack or msg as we are going to overwrite mailbox */
253	e1000_check_for_ack_vf(hw);
254	e1000_check_for_msg_vf(hw);
255
256	/* copy the caller specified message to the mailbox memory buffer */
257	for (i = 0; i < size; i++)
258		array_ew32(VMBMEM(0), i, msg[i]);
259
260	/* update stats */
261	hw->mbx.stats.msgs_tx++;
262
263	/* Drop VFU and interrupt the PF to tell it a message has been sent */
264	ew32(V2PMAILBOX(0), E1000_V2PMAILBOX_REQ);
265
266out_no_write:
267	return err;
268}
269
270/**
271 *  e1000_read_mbx_vf - Reads a message from the inbox intended for VF
272 *  @hw: pointer to the HW structure
273 *  @msg: The message buffer
274 *  @size: Length of buffer
275 *
276 *  returns SUCCESS if it successfully read message from buffer
277 **/
278static s32 e1000_read_mbx_vf(struct e1000_hw *hw, u32 *msg, u16 size)
279{
280	s32 err;
281	u16 i;
282
283	lockdep_assert_held(&hw->mbx_lock);
284
285	/* lock the mailbox to prevent pf/vf race condition */
286	err = e1000_obtain_mbx_lock_vf(hw);
287	if (err)
288		goto out_no_read;
289
290	/* copy the message from the mailbox memory buffer */
291	for (i = 0; i < size; i++)
292		msg[i] = array_er32(VMBMEM(0), i);
293
294	/* Acknowledge receipt and release mailbox, then we're done */
295	ew32(V2PMAILBOX(0), E1000_V2PMAILBOX_ACK);
296
297	/* update stats */
298	hw->mbx.stats.msgs_rx++;
299
300out_no_read:
301	return err;
302}
303
304/**
305 *  e1000_init_mbx_params_vf - set initial values for VF mailbox
306 *  @hw: pointer to the HW structure
307 *
308 *  Initializes the hw->mbx struct to correct values for VF mailbox
309 */
310s32 e1000_init_mbx_params_vf(struct e1000_hw *hw)
311{
312	struct e1000_mbx_info *mbx = &hw->mbx;
313
314	/* start mailbox as timed out and let the reset_hw call set the timeout
315	 * value to being communications
316	 */
317	mbx->timeout = 0;
318	mbx->usec_delay = E1000_VF_MBX_INIT_DELAY;
319
320	mbx->size = E1000_VFMAILBOX_SIZE;
321
322	mbx->ops.read = e1000_read_mbx_vf;
323	mbx->ops.write = e1000_write_mbx_vf;
324	mbx->ops.read_posted = e1000_read_posted_mbx;
325	mbx->ops.write_posted = e1000_write_posted_mbx;
326	mbx->ops.check_for_msg = e1000_check_for_msg_vf;
327	mbx->ops.check_for_ack = e1000_check_for_ack_vf;
328	mbx->ops.check_for_rst = e1000_check_for_rst_vf;
329
330	mbx->stats.msgs_tx = 0;
331	mbx->stats.msgs_rx = 0;
332	mbx->stats.reqs = 0;
333	mbx->stats.acks = 0;
334	mbx->stats.rsts = 0;
335
336	return E1000_SUCCESS;
337}
338