1 // SPDX-License-Identifier: GPL-2.0+
2 /* Copyright (c) 2015-2016 Quantenna Communications. All rights reserved. */
3
4 #include <linux/types.h>
5 #include <linux/io.h>
6
7 #include "shm_ipc.h"
8
9 #undef pr_fmt
10 #define pr_fmt(fmt) "qtnfmac shm_ipc: %s: " fmt, __func__
11
qtnf_shm_ipc_has_new_data(struct qtnf_shm_ipc * ipc)12 static bool qtnf_shm_ipc_has_new_data(struct qtnf_shm_ipc *ipc)
13 {
14 const u32 flags = readl(&ipc->shm_region->headroom.hdr.flags);
15
16 return (flags & QTNF_SHM_IPC_NEW_DATA);
17 }
18
qtnf_shm_handle_new_data(struct qtnf_shm_ipc * ipc)19 static void qtnf_shm_handle_new_data(struct qtnf_shm_ipc *ipc)
20 {
21 size_t size;
22 bool rx_buff_ok = true;
23 struct qtnf_shm_ipc_region_header __iomem *shm_reg_hdr;
24
25 shm_reg_hdr = &ipc->shm_region->headroom.hdr;
26
27 size = readw(&shm_reg_hdr->data_len);
28
29 if (unlikely(size == 0 || size > QTN_IPC_MAX_DATA_SZ)) {
30 pr_err("wrong rx packet size: %zu\n", size);
31 rx_buff_ok = false;
32 }
33
34 if (likely(rx_buff_ok)) {
35 ipc->rx_packet_count++;
36 ipc->rx_callback.fn(ipc->rx_callback.arg,
37 ipc->shm_region->data, size);
38 }
39
40 writel(QTNF_SHM_IPC_ACK, &shm_reg_hdr->flags);
41 readl(&shm_reg_hdr->flags); /* flush PCIe write */
42
43 ipc->interrupt.fn(ipc->interrupt.arg);
44 }
45
qtnf_shm_ipc_irq_work(struct work_struct * work)46 static void qtnf_shm_ipc_irq_work(struct work_struct *work)
47 {
48 struct qtnf_shm_ipc *ipc = container_of(work, struct qtnf_shm_ipc,
49 irq_work);
50
51 while (qtnf_shm_ipc_has_new_data(ipc))
52 qtnf_shm_handle_new_data(ipc);
53 }
54
qtnf_shm_ipc_irq_inbound_handler(struct qtnf_shm_ipc * ipc)55 static void qtnf_shm_ipc_irq_inbound_handler(struct qtnf_shm_ipc *ipc)
56 {
57 u32 flags;
58
59 flags = readl(&ipc->shm_region->headroom.hdr.flags);
60
61 if (flags & QTNF_SHM_IPC_NEW_DATA)
62 queue_work(ipc->workqueue, &ipc->irq_work);
63 }
64
qtnf_shm_ipc_irq_outbound_handler(struct qtnf_shm_ipc * ipc)65 static void qtnf_shm_ipc_irq_outbound_handler(struct qtnf_shm_ipc *ipc)
66 {
67 u32 flags;
68
69 if (!READ_ONCE(ipc->waiting_for_ack))
70 return;
71
72 flags = readl(&ipc->shm_region->headroom.hdr.flags);
73
74 if (flags & QTNF_SHM_IPC_ACK) {
75 WRITE_ONCE(ipc->waiting_for_ack, 0);
76 complete(&ipc->tx_completion);
77 }
78 }
79
qtnf_shm_ipc_init(struct qtnf_shm_ipc * ipc,enum qtnf_shm_ipc_direction direction,struct qtnf_shm_ipc_region __iomem * shm_region,struct workqueue_struct * workqueue,const struct qtnf_shm_ipc_int * interrupt,const struct qtnf_shm_ipc_rx_callback * rx_callback)80 int qtnf_shm_ipc_init(struct qtnf_shm_ipc *ipc,
81 enum qtnf_shm_ipc_direction direction,
82 struct qtnf_shm_ipc_region __iomem *shm_region,
83 struct workqueue_struct *workqueue,
84 const struct qtnf_shm_ipc_int *interrupt,
85 const struct qtnf_shm_ipc_rx_callback *rx_callback)
86 {
87 BUILD_BUG_ON(offsetof(struct qtnf_shm_ipc_region, data) !=
88 QTN_IPC_REG_HDR_SZ);
89 BUILD_BUG_ON(sizeof(struct qtnf_shm_ipc_region) > QTN_IPC_REG_SZ);
90
91 ipc->shm_region = shm_region;
92 ipc->direction = direction;
93 ipc->interrupt = *interrupt;
94 ipc->rx_callback = *rx_callback;
95 ipc->tx_packet_count = 0;
96 ipc->rx_packet_count = 0;
97 ipc->workqueue = workqueue;
98 ipc->waiting_for_ack = 0;
99 ipc->tx_timeout_count = 0;
100
101 switch (direction) {
102 case QTNF_SHM_IPC_OUTBOUND:
103 ipc->irq_handler = qtnf_shm_ipc_irq_outbound_handler;
104 break;
105 case QTNF_SHM_IPC_INBOUND:
106 ipc->irq_handler = qtnf_shm_ipc_irq_inbound_handler;
107 break;
108 default:
109 return -EINVAL;
110 }
111
112 INIT_WORK(&ipc->irq_work, qtnf_shm_ipc_irq_work);
113 init_completion(&ipc->tx_completion);
114
115 return 0;
116 }
117
qtnf_shm_ipc_free(struct qtnf_shm_ipc * ipc)118 void qtnf_shm_ipc_free(struct qtnf_shm_ipc *ipc)
119 {
120 complete_all(&ipc->tx_completion);
121 }
122
qtnf_shm_ipc_send(struct qtnf_shm_ipc * ipc,const u8 * buf,size_t size)123 int qtnf_shm_ipc_send(struct qtnf_shm_ipc *ipc, const u8 *buf, size_t size)
124 {
125 int ret = 0;
126 struct qtnf_shm_ipc_region_header __iomem *shm_reg_hdr;
127
128 shm_reg_hdr = &ipc->shm_region->headroom.hdr;
129
130 if (unlikely(size > QTN_IPC_MAX_DATA_SZ))
131 return -E2BIG;
132
133 ipc->tx_packet_count++;
134
135 writew(size, &shm_reg_hdr->data_len);
136 memcpy_toio(ipc->shm_region->data, buf, size);
137
138 /* sync previous writes before proceeding */
139 dma_wmb();
140
141 WRITE_ONCE(ipc->waiting_for_ack, 1);
142
143 /* sync previous memory write before announcing new data ready */
144 wmb();
145
146 writel(QTNF_SHM_IPC_NEW_DATA, &shm_reg_hdr->flags);
147 readl(&shm_reg_hdr->flags); /* flush PCIe write */
148
149 ipc->interrupt.fn(ipc->interrupt.arg);
150
151 if (!wait_for_completion_timeout(&ipc->tx_completion,
152 QTN_SHM_IPC_ACK_TIMEOUT)) {
153 ret = -ETIMEDOUT;
154 ipc->tx_timeout_count++;
155 pr_err("TX ACK timeout\n");
156 }
157
158 /* now we're not waiting for ACK even in case of timeout */
159 WRITE_ONCE(ipc->waiting_for_ack, 0);
160
161 return ret;
162 }
163