1 /*
2  * Copyright 2008-2010 Cisco Systems, Inc.  All rights reserved.
3  * Copyright 2007 Nuova Systems, Inc.  All rights reserved.
4  *
5  * This program is free software; you may redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; version 2 of the License.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
10  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
11  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
12  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
13  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
14  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
15  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
16  * SOFTWARE.
17  *
18  */
19 
20 #ifndef _VNIC_RQ_H_
21 #define _VNIC_RQ_H_
22 
23 #include <linux/pci.h>
24 
25 #include "vnic_dev.h"
26 #include "vnic_cq.h"
27 
28 /* Receive queue control */
29 struct vnic_rq_ctrl {
30 	u64 ring_base;			/* 0x00 */
31 	u32 ring_size;			/* 0x08 */
32 	u32 pad0;
33 	u32 posted_index;		/* 0x10 */
34 	u32 pad1;
35 	u32 cq_index;			/* 0x18 */
36 	u32 pad2;
37 	u32 enable;			/* 0x20 */
38 	u32 pad3;
39 	u32 running;			/* 0x28 */
40 	u32 pad4;
41 	u32 fetch_index;		/* 0x30 */
42 	u32 pad5;
43 	u32 error_interrupt_enable;	/* 0x38 */
44 	u32 pad6;
45 	u32 error_interrupt_offset;	/* 0x40 */
46 	u32 pad7;
47 	u32 error_status;		/* 0x48 */
48 	u32 pad8;
49 	u32 dropped_packet_count;	/* 0x50 */
50 	u32 pad9;
51 	u32 dropped_packet_count_rc;	/* 0x58 */
52 	u32 pad10;
53 };
54 
55 /* Break the vnic_rq_buf allocations into blocks of 32/64 entries */
56 #define VNIC_RQ_BUF_MIN_BLK_ENTRIES 32
57 #define VNIC_RQ_BUF_DFLT_BLK_ENTRIES 64
58 #define VNIC_RQ_BUF_BLK_ENTRIES(entries) \
59 	((unsigned int)((entries < VNIC_RQ_BUF_DFLT_BLK_ENTRIES) ? \
60 	VNIC_RQ_BUF_MIN_BLK_ENTRIES : VNIC_RQ_BUF_DFLT_BLK_ENTRIES))
61 #define VNIC_RQ_BUF_BLK_SZ(entries) \
62 	(VNIC_RQ_BUF_BLK_ENTRIES(entries) * sizeof(struct vnic_rq_buf))
63 #define VNIC_RQ_BUF_BLKS_NEEDED(entries) \
64 	DIV_ROUND_UP(entries, VNIC_RQ_BUF_BLK_ENTRIES(entries))
65 #define VNIC_RQ_BUF_BLKS_MAX VNIC_RQ_BUF_BLKS_NEEDED(4096)
66 
67 struct vnic_rq_buf {
68 	struct vnic_rq_buf *next;
69 	dma_addr_t dma_addr;
70 	void *os_buf;
71 	unsigned int os_buf_index;
72 	unsigned int len;
73 	unsigned int index;
74 	void *desc;
75 	uint64_t wr_id;
76 };
77 
78 struct vnic_rq {
79 	unsigned int index;
80 	struct vnic_dev *vdev;
81 	struct vnic_rq_ctrl __iomem *ctrl;              /* memory-mapped */
82 	struct vnic_dev_ring ring;
83 	struct vnic_rq_buf *bufs[VNIC_RQ_BUF_BLKS_MAX];
84 	struct vnic_rq_buf *to_use;
85 	struct vnic_rq_buf *to_clean;
86 	void *os_buf_head;
87 	unsigned int pkts_outstanding;
88 };
89 
90 static inline unsigned int vnic_rq_desc_avail(struct vnic_rq *rq)
91 {
92 	/* how many does SW own? */
93 	return rq->ring.desc_avail;
94 }
95 
96 static inline unsigned int vnic_rq_desc_used(struct vnic_rq *rq)
97 {
98 	/* how many does HW own? */
99 	return rq->ring.desc_count - rq->ring.desc_avail - 1;
100 }
101 
102 static inline void *vnic_rq_next_desc(struct vnic_rq *rq)
103 {
104 	return rq->to_use->desc;
105 }
106 
107 static inline unsigned int vnic_rq_next_index(struct vnic_rq *rq)
108 {
109 	return rq->to_use->index;
110 }
111 
112 static inline void vnic_rq_post(struct vnic_rq *rq,
113 	void *os_buf, unsigned int os_buf_index,
114 	dma_addr_t dma_addr, unsigned int len,
115 	uint64_t wrid)
116 {
117 	struct vnic_rq_buf *buf = rq->to_use;
118 
119 	buf->os_buf = os_buf;
120 	buf->os_buf_index = os_buf_index;
121 	buf->dma_addr = dma_addr;
122 	buf->len = len;
123 	buf->wr_id = wrid;
124 
125 	buf = buf->next;
126 	rq->to_use = buf;
127 	rq->ring.desc_avail--;
128 
129 	/* Move the posted_index every nth descriptor
130 	 */
131 
132 #ifndef VNIC_RQ_RETURN_RATE
133 #define VNIC_RQ_RETURN_RATE		0xf	/* keep 2^n - 1 */
134 #endif
135 
136 	if ((buf->index & VNIC_RQ_RETURN_RATE) == 0) {
137 		/* Adding write memory barrier prevents compiler and/or CPU
138 		 * reordering, thus avoiding descriptor posting before
139 		 * descriptor is initialized. Otherwise, hardware can read
140 		 * stale descriptor fields.
141 		 */
142 		wmb();
143 		iowrite32(buf->index, &rq->ctrl->posted_index);
144 	}
145 }
146 
147 static inline void vnic_rq_return_descs(struct vnic_rq *rq, unsigned int count)
148 {
149 	rq->ring.desc_avail += count;
150 }
151 
152 enum desc_return_options {
153 	VNIC_RQ_RETURN_DESC,
154 	VNIC_RQ_DEFER_RETURN_DESC,
155 };
156 
157 static inline void vnic_rq_service(struct vnic_rq *rq,
158 	struct cq_desc *cq_desc, u16 completed_index,
159 	int desc_return, void (*buf_service)(struct vnic_rq *rq,
160 	struct cq_desc *cq_desc, struct vnic_rq_buf *buf,
161 	int skipped, void *opaque), void *opaque)
162 {
163 	struct vnic_rq_buf *buf;
164 	int skipped;
165 
166 	buf = rq->to_clean;
167 	while (1) {
168 
169 		skipped = (buf->index != completed_index);
170 
171 		(*buf_service)(rq, cq_desc, buf, skipped, opaque);
172 
173 		if (desc_return == VNIC_RQ_RETURN_DESC)
174 			rq->ring.desc_avail++;
175 
176 		rq->to_clean = buf->next;
177 
178 		if (!skipped)
179 			break;
180 
181 		buf = rq->to_clean;
182 	}
183 }
184 
185 static inline int vnic_rq_fill(struct vnic_rq *rq,
186 	int (*buf_fill)(struct vnic_rq *rq))
187 {
188 	int err;
189 
190 	while (vnic_rq_desc_avail(rq) > 0) {
191 
192 		err = (*buf_fill)(rq);
193 		if (err)
194 			return err;
195 	}
196 
197 	return 0;
198 }
199 
200 void vnic_rq_free(struct vnic_rq *rq);
201 int vnic_rq_alloc(struct vnic_dev *vdev, struct vnic_rq *rq, unsigned int index,
202 	unsigned int desc_count, unsigned int desc_size);
203 void vnic_rq_init(struct vnic_rq *rq, unsigned int cq_index,
204 	unsigned int error_interrupt_enable,
205 	unsigned int error_interrupt_offset);
206 unsigned int vnic_rq_error_status(struct vnic_rq *rq);
207 void vnic_rq_enable(struct vnic_rq *rq);
208 int vnic_rq_disable(struct vnic_rq *rq);
209 void vnic_rq_clean(struct vnic_rq *rq,
210 	void (*buf_clean)(struct vnic_rq *rq, struct vnic_rq_buf *buf));
211 
212 #endif /* _VNIC_RQ_H_ */
213