xref: /linux/drivers/hid/intel-ish-hid/ishtp/dma-if.c (revision 9a87ffc99ec8eb8d35eed7c4f816d75f5cc9662e)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ISHTP DMA I/F functions
4  *
5  * Copyright (c) 2003-2016, Intel Corporation.
6  */
7 
8 #include <linux/slab.h>
9 #include <linux/sched.h>
10 #include <linux/wait.h>
11 #include <linux/delay.h>
12 #include <linux/dma-mapping.h>
13 #include "ishtp-dev.h"
14 #include "client.h"
15 
16 /**
17  * ishtp_cl_alloc_dma_buf() - Allocate DMA RX and TX buffer
18  * @dev: ishtp device
19  *
20  * Allocate RX and TX DMA buffer once during bus setup.
21  * It allocates 1MB, RX and TX DMA buffer, which are divided
22  * into slots.
23  */
ishtp_cl_alloc_dma_buf(struct ishtp_device * dev)24 void	ishtp_cl_alloc_dma_buf(struct ishtp_device *dev)
25 {
26 	dma_addr_t	h;
27 
28 	if (dev->ishtp_host_dma_tx_buf)
29 		return;
30 
31 	dev->ishtp_host_dma_tx_buf_size = 1024*1024;
32 	dev->ishtp_host_dma_rx_buf_size = 1024*1024;
33 
34 	/* Allocate Tx buffer and init usage bitmap */
35 	dev->ishtp_host_dma_tx_buf = dma_alloc_coherent(dev->devc,
36 					dev->ishtp_host_dma_tx_buf_size,
37 					&h, GFP_KERNEL);
38 	if (dev->ishtp_host_dma_tx_buf)
39 		dev->ishtp_host_dma_tx_buf_phys = h;
40 
41 	dev->ishtp_dma_num_slots = dev->ishtp_host_dma_tx_buf_size /
42 						DMA_SLOT_SIZE;
43 
44 	dev->ishtp_dma_tx_map = kcalloc(dev->ishtp_dma_num_slots,
45 					sizeof(uint8_t),
46 					GFP_KERNEL);
47 	spin_lock_init(&dev->ishtp_dma_tx_lock);
48 
49 	/* Allocate Rx buffer */
50 	dev->ishtp_host_dma_rx_buf = dma_alloc_coherent(dev->devc,
51 					dev->ishtp_host_dma_rx_buf_size,
52 					 &h, GFP_KERNEL);
53 
54 	if (dev->ishtp_host_dma_rx_buf)
55 		dev->ishtp_host_dma_rx_buf_phys = h;
56 }
57 
58 /**
59  * ishtp_cl_free_dma_buf() - Free DMA RX and TX buffer
60  * @dev: ishtp device
61  *
62  * Free DMA buffer when all clients are released. This is
63  * only happens during error path in ISH built in driver
64  * model
65  */
ishtp_cl_free_dma_buf(struct ishtp_device * dev)66 void	ishtp_cl_free_dma_buf(struct ishtp_device *dev)
67 {
68 	dma_addr_t	h;
69 
70 	if (dev->ishtp_host_dma_tx_buf) {
71 		h = dev->ishtp_host_dma_tx_buf_phys;
72 		dma_free_coherent(dev->devc, dev->ishtp_host_dma_tx_buf_size,
73 				  dev->ishtp_host_dma_tx_buf, h);
74 	}
75 
76 	if (dev->ishtp_host_dma_rx_buf) {
77 		h = dev->ishtp_host_dma_rx_buf_phys;
78 		dma_free_coherent(dev->devc, dev->ishtp_host_dma_rx_buf_size,
79 				  dev->ishtp_host_dma_rx_buf, h);
80 	}
81 
82 	kfree(dev->ishtp_dma_tx_map);
83 	dev->ishtp_host_dma_tx_buf = NULL;
84 	dev->ishtp_host_dma_rx_buf = NULL;
85 	dev->ishtp_dma_tx_map = NULL;
86 }
87 
88 /*
89  * ishtp_cl_get_dma_send_buf() - Get a DMA memory slot
90  * @dev:	ishtp device
91  * @size:	Size of memory to get
92  *
93  * Find and return free address of "size" bytes in dma tx buffer.
94  * the function will mark this address as "in-used" memory.
95  *
96  * Return: NULL when no free buffer else a buffer to copy
97  */
ishtp_cl_get_dma_send_buf(struct ishtp_device * dev,uint32_t size)98 void *ishtp_cl_get_dma_send_buf(struct ishtp_device *dev,
99 				uint32_t size)
100 {
101 	unsigned long	flags;
102 	int i, j, free;
103 	/* additional slot is needed if there is rem */
104 	int required_slots = (size / DMA_SLOT_SIZE)
105 		+ 1 * (size % DMA_SLOT_SIZE != 0);
106 
107 	if (!dev->ishtp_dma_tx_map) {
108 		dev_err(dev->devc, "Fail to allocate Tx map\n");
109 		return NULL;
110 	}
111 
112 	spin_lock_irqsave(&dev->ishtp_dma_tx_lock, flags);
113 	for (i = 0; i <= (dev->ishtp_dma_num_slots - required_slots); i++) {
114 		free = 1;
115 		for (j = 0; j < required_slots; j++)
116 			if (dev->ishtp_dma_tx_map[i+j]) {
117 				free = 0;
118 				i += j;
119 				break;
120 			}
121 		if (free) {
122 			/* mark memory as "caught" */
123 			for (j = 0; j < required_slots; j++)
124 				dev->ishtp_dma_tx_map[i+j] = 1;
125 			spin_unlock_irqrestore(&dev->ishtp_dma_tx_lock, flags);
126 			return (i * DMA_SLOT_SIZE) +
127 				(unsigned char *)dev->ishtp_host_dma_tx_buf;
128 		}
129 	}
130 	spin_unlock_irqrestore(&dev->ishtp_dma_tx_lock, flags);
131 	dev_err(dev->devc, "No free DMA buffer to send msg\n");
132 	return NULL;
133 }
134 
135 /*
136  * ishtp_cl_release_dma_acked_mem() - Release DMA memory slot
137  * @dev:	ishtp device
138  * @msg_addr:	message address of slot
139  * @size:	Size of memory to get
140  *
141  * Release_dma_acked_mem - returnes the acked memory to free list.
142  * (from msg_addr, size bytes long)
143  */
ishtp_cl_release_dma_acked_mem(struct ishtp_device * dev,void * msg_addr,uint8_t size)144 void ishtp_cl_release_dma_acked_mem(struct ishtp_device *dev,
145 				    void *msg_addr,
146 				    uint8_t size)
147 {
148 	unsigned long	flags;
149 	int acked_slots = (size / DMA_SLOT_SIZE)
150 		+ 1 * (size % DMA_SLOT_SIZE != 0);
151 	int i, j;
152 
153 	if ((msg_addr - dev->ishtp_host_dma_tx_buf) % DMA_SLOT_SIZE) {
154 		dev_err(dev->devc, "Bad DMA Tx ack address\n");
155 		return;
156 	}
157 
158 	if (!dev->ishtp_dma_tx_map) {
159 		dev_err(dev->devc, "Fail to allocate Tx map\n");
160 		return;
161 	}
162 
163 	i = (msg_addr - dev->ishtp_host_dma_tx_buf) / DMA_SLOT_SIZE;
164 	spin_lock_irqsave(&dev->ishtp_dma_tx_lock, flags);
165 	for (j = 0; j < acked_slots; j++) {
166 		if ((i + j) >= dev->ishtp_dma_num_slots ||
167 					!dev->ishtp_dma_tx_map[i+j]) {
168 			/* no such slot, or memory is already free */
169 			spin_unlock_irqrestore(&dev->ishtp_dma_tx_lock, flags);
170 			dev_err(dev->devc, "Bad DMA Tx ack address\n");
171 			return;
172 		}
173 		dev->ishtp_dma_tx_map[i+j] = 0;
174 	}
175 	spin_unlock_irqrestore(&dev->ishtp_dma_tx_lock, flags);
176 }
177