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 #include <linux/kernel.h>
21 #include <linux/errno.h>
22 #include <linux/types.h>
23 #include <linux/pci.h>
24 #include <linux/delay.h>
25 #include <linux/slab.h>
26 
27 #include "vnic_dev.h"
28 #include "vnic_rq.h"
29 #include "enic.h"
30 
31 static int vnic_rq_alloc_bufs(struct vnic_rq *rq)
32 {
33 	struct vnic_rq_buf *buf;
34 	unsigned int i, j, count = rq->ring.desc_count;
35 	unsigned int blks = VNIC_RQ_BUF_BLKS_NEEDED(count);
36 
37 	for (i = 0; i < blks; i++) {
38 		rq->bufs[i] = kzalloc(VNIC_RQ_BUF_BLK_SZ(count), GFP_KERNEL);
39 		if (!rq->bufs[i])
40 			return -ENOMEM;
41 	}
42 
43 	for (i = 0; i < blks; i++) {
44 		buf = rq->bufs[i];
45 		for (j = 0; j < VNIC_RQ_BUF_BLK_ENTRIES(count); j++) {
46 			buf->index = i * VNIC_RQ_BUF_BLK_ENTRIES(count) + j;
47 			buf->desc = (u8 *)rq->ring.descs +
48 				rq->ring.desc_size * buf->index;
49 			if (buf->index + 1 == count) {
50 				buf->next = rq->bufs[0];
51 				break;
52 			} else if (j + 1 == VNIC_RQ_BUF_BLK_ENTRIES(count)) {
53 				buf->next = rq->bufs[i + 1];
54 			} else {
55 				buf->next = buf + 1;
56 				buf++;
57 			}
58 		}
59 	}
60 
61 	rq->to_use = rq->to_clean = rq->bufs[0];
62 
63 	return 0;
64 }
65 
66 void vnic_rq_free(struct vnic_rq *rq)
67 {
68 	struct vnic_dev *vdev;
69 	unsigned int i;
70 
71 	vdev = rq->vdev;
72 
73 	vnic_dev_free_desc_ring(vdev, &rq->ring);
74 
75 	for (i = 0; i < VNIC_RQ_BUF_BLKS_MAX; i++) {
76 		if (rq->bufs[i]) {
77 			kfree(rq->bufs[i]);
78 			rq->bufs[i] = NULL;
79 		}
80 	}
81 
82 	rq->ctrl = NULL;
83 }
84 
85 int vnic_rq_alloc(struct vnic_dev *vdev, struct vnic_rq *rq, unsigned int index,
86 	unsigned int desc_count, unsigned int desc_size)
87 {
88 	int err;
89 
90 	rq->index = index;
91 	rq->vdev = vdev;
92 
93 	rq->ctrl = vnic_dev_get_res(vdev, RES_TYPE_RQ, index);
94 	if (!rq->ctrl) {
95 		vdev_err(vdev, "Failed to hook RQ[%d] resource\n", index);
96 		return -EINVAL;
97 	}
98 
99 	vnic_rq_disable(rq);
100 
101 	err = vnic_dev_alloc_desc_ring(vdev, &rq->ring, desc_count, desc_size);
102 	if (err)
103 		return err;
104 
105 	err = vnic_rq_alloc_bufs(rq);
106 	if (err) {
107 		vnic_rq_free(rq);
108 		return err;
109 	}
110 
111 	return 0;
112 }
113 
114 static void vnic_rq_init_start(struct vnic_rq *rq, unsigned int cq_index,
115 	unsigned int fetch_index, unsigned int posted_index,
116 	unsigned int error_interrupt_enable,
117 	unsigned int error_interrupt_offset)
118 {
119 	u64 paddr;
120 	unsigned int count = rq->ring.desc_count;
121 
122 	paddr = (u64)rq->ring.base_addr | VNIC_PADDR_TARGET;
123 	writeq(paddr, &rq->ctrl->ring_base);
124 	iowrite32(count, &rq->ctrl->ring_size);
125 	iowrite32(cq_index, &rq->ctrl->cq_index);
126 	iowrite32(error_interrupt_enable, &rq->ctrl->error_interrupt_enable);
127 	iowrite32(error_interrupt_offset, &rq->ctrl->error_interrupt_offset);
128 	iowrite32(0, &rq->ctrl->dropped_packet_count);
129 	iowrite32(0, &rq->ctrl->error_status);
130 	iowrite32(fetch_index, &rq->ctrl->fetch_index);
131 	iowrite32(posted_index, &rq->ctrl->posted_index);
132 
133 	rq->to_use = rq->to_clean =
134 		&rq->bufs[fetch_index / VNIC_RQ_BUF_BLK_ENTRIES(count)]
135 			[fetch_index % VNIC_RQ_BUF_BLK_ENTRIES(count)];
136 }
137 
138 void vnic_rq_init(struct vnic_rq *rq, unsigned int cq_index,
139 	unsigned int error_interrupt_enable,
140 	unsigned int error_interrupt_offset)
141 {
142 	vnic_rq_init_start(rq, cq_index, 0, 0, error_interrupt_enable,
143 			   error_interrupt_offset);
144 }
145 
146 unsigned int vnic_rq_error_status(struct vnic_rq *rq)
147 {
148 	return ioread32(&rq->ctrl->error_status);
149 }
150 
151 void vnic_rq_enable(struct vnic_rq *rq)
152 {
153 	iowrite32(1, &rq->ctrl->enable);
154 }
155 
156 int vnic_rq_disable(struct vnic_rq *rq)
157 {
158 	unsigned int wait;
159 	struct vnic_dev *vdev = rq->vdev;
160 	int i;
161 
162 	/* Due to a race condition with clearing RQ "mini-cache" in hw, we need
163 	 * to disable the RQ twice to guarantee that stale descriptors are not
164 	 * used when this RQ is re-enabled.
165 	 */
166 	for (i = 0; i < 2; i++) {
167 		iowrite32(0, &rq->ctrl->enable);
168 
169 		/* Wait for HW to ACK disable request */
170 		for (wait = 20000; wait > 0; wait--)
171 			if (!ioread32(&rq->ctrl->running))
172 				break;
173 		if (!wait) {
174 			vdev_neterr(vdev, "Failed to disable RQ[%d]\n",
175 				    rq->index);
176 
177 			return -ETIMEDOUT;
178 		}
179 	}
180 
181 	return 0;
182 }
183 
184 void vnic_rq_clean(struct vnic_rq *rq,
185 	void (*buf_clean)(struct vnic_rq *rq, struct vnic_rq_buf *buf))
186 {
187 	struct vnic_rq_buf *buf;
188 	u32 fetch_index;
189 	unsigned int count = rq->ring.desc_count;
190 	int i;
191 
192 	buf = rq->to_clean;
193 
194 	for (i = 0; i < rq->ring.desc_count; i++) {
195 		(*buf_clean)(rq, buf);
196 		buf = buf->next;
197 	}
198 	rq->ring.desc_avail = rq->ring.desc_count - 1;
199 
200 	/* Use current fetch_index as the ring starting point */
201 	fetch_index = ioread32(&rq->ctrl->fetch_index);
202 
203 	if (fetch_index == 0xFFFFFFFF) { /* check for hardware gone  */
204 		/* Hardware surprise removal: reset fetch_index */
205 		fetch_index = 0;
206 	}
207 	rq->to_use = rq->to_clean =
208 		&rq->bufs[fetch_index / VNIC_RQ_BUF_BLK_ENTRIES(count)]
209 			[fetch_index % VNIC_RQ_BUF_BLK_ENTRIES(count)];
210 	iowrite32(fetch_index, &rq->ctrl->posted_index);
211 
212 	/* Anytime we write fetch_index, we need to re-write 0 to rq->enable
213 	 * to re-sync internal VIC state.
214 	 */
215 	iowrite32(0, &rq->ctrl->enable);
216 
217 	vnic_dev_clear_desc_ring(&rq->ring);
218 }
219 
220