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1da177e4 LT |
1 | /* |
2 | * linux/arch/m68k/atari/stmda.c | |
3 | * | |
4 | * Copyright (C) 1994 Roman Hodek | |
5 | * | |
6 | * | |
7 | * This file is subject to the terms and conditions of the GNU General Public | |
8 | * License. See the file COPYING in the main directory of this archive | |
9 | * for more details. | |
10 | */ | |
11 | ||
12 | ||
13 | /* This file contains some function for controlling the access to the */ | |
14 | /* ST-DMA chip that may be shared between devices. Currently we have: */ | |
15 | /* TT: Floppy and ACSI bus */ | |
16 | /* Falcon: Floppy and SCSI */ | |
17 | /* */ | |
18 | /* The controlling functions set up a wait queue for access to the */ | |
19 | /* ST-DMA chip. Callers to stdma_lock() that cannot granted access are */ | |
20 | /* put onto a queue and waked up later if the owner calls */ | |
21 | /* stdma_release(). Additionally, the caller gives his interrupt */ | |
22 | /* service routine to stdma_lock(). */ | |
23 | /* */ | |
24 | /* On the Falcon, the IDE bus uses just the ACSI/Floppy interrupt, but */ | |
25 | /* not the ST-DMA chip itself. So falhd.c needs not to lock the */ | |
26 | /* chip. The interrupt is routed to falhd.c if IDE is configured, the */ | |
27 | /* model is a Falcon and the interrupt was caused by the HD controller */ | |
28 | /* (can be determined by looking at its status register). */ | |
29 | ||
30 | ||
31 | #include <linux/types.h> | |
32 | #include <linux/kdev_t.h> | |
33 | #include <linux/genhd.h> | |
34 | #include <linux/sched.h> | |
35 | #include <linux/init.h> | |
36 | #include <linux/interrupt.h> | |
37 | #include <linux/wait.h> | |
a3b2004a | 38 | #include <linux/module.h> |
1da177e4 LT |
39 | |
40 | #include <asm/atari_stdma.h> | |
41 | #include <asm/atariints.h> | |
42 | #include <asm/atarihw.h> | |
43 | #include <asm/io.h> | |
44 | #include <asm/irq.h> | |
45 | ||
46 | static int stdma_locked; /* the semaphore */ | |
47 | /* int func to be called */ | |
40220c1a | 48 | static irq_handler_t stdma_isr; |
1da177e4 LT |
49 | static void *stdma_isr_data; /* data passed to isr */ |
50 | static DECLARE_WAIT_QUEUE_HEAD(stdma_wait); /* wait queue for ST-DMA */ | |
51 | ||
52 | ||
53 | ||
54 | ||
55 | /***************************** Prototypes *****************************/ | |
56 | ||
2850bc27 | 57 | static irqreturn_t stdma_int (int irq, void *dummy); |
1da177e4 LT |
58 | |
59 | /************************* End of Prototypes **************************/ | |
60 | ||
61 | ||
62 | ||
63 | /* | |
64 | * Function: void stdma_lock( isrfunc isr, void *data ) | |
65 | * | |
66 | * Purpose: Tries to get a lock on the ST-DMA chip that is used by more | |
67 | * then one device driver. Waits on stdma_wait until lock is free. | |
68 | * stdma_lock() may not be called from an interrupt! You have to | |
69 | * get the lock in your main routine and release it when your | |
70 | * request is finished. | |
71 | * | |
72 | * Inputs: A interrupt function that is called until the lock is | |
73 | * released. | |
74 | * | |
75 | * Returns: nothing | |
76 | * | |
77 | */ | |
78 | ||
40220c1a | 79 | void stdma_lock(irq_handler_t handler, void *data) |
1da177e4 LT |
80 | { |
81 | unsigned long flags; | |
82 | ||
83 | local_irq_save(flags); /* protect lock */ | |
84 | ||
85 | /* Since the DMA is used for file system purposes, we | |
86 | have to sleep uninterruptible (there may be locked | |
87 | buffers) */ | |
88 | wait_event(stdma_wait, !stdma_locked); | |
89 | ||
90 | stdma_locked = 1; | |
91 | stdma_isr = handler; | |
92 | stdma_isr_data = data; | |
93 | local_irq_restore(flags); | |
94 | } | |
a3b2004a | 95 | EXPORT_SYMBOL(stdma_lock); |
1da177e4 LT |
96 | |
97 | ||
98 | /* | |
99 | * Function: void stdma_release( void ) | |
100 | * | |
101 | * Purpose: Releases the lock on the ST-DMA chip. | |
102 | * | |
103 | * Inputs: none | |
104 | * | |
105 | * Returns: nothing | |
106 | * | |
107 | */ | |
108 | ||
109 | void stdma_release(void) | |
110 | { | |
111 | unsigned long flags; | |
112 | ||
113 | local_irq_save(flags); | |
114 | ||
115 | stdma_locked = 0; | |
116 | stdma_isr = NULL; | |
117 | stdma_isr_data = NULL; | |
118 | wake_up(&stdma_wait); | |
119 | ||
120 | local_irq_restore(flags); | |
121 | } | |
a3b2004a | 122 | EXPORT_SYMBOL(stdma_release); |
1da177e4 LT |
123 | |
124 | ||
125 | /* | |
126 | * Function: int stdma_others_waiting( void ) | |
127 | * | |
128 | * Purpose: Check if someone waits for the ST-DMA lock. | |
129 | * | |
130 | * Inputs: none | |
131 | * | |
132 | * Returns: 0 if no one is waiting, != 0 otherwise | |
133 | * | |
134 | */ | |
135 | ||
136 | int stdma_others_waiting(void) | |
137 | { | |
138 | return waitqueue_active(&stdma_wait); | |
139 | } | |
a3b2004a | 140 | EXPORT_SYMBOL(stdma_others_waiting); |
1da177e4 LT |
141 | |
142 | ||
143 | /* | |
144 | * Function: int stdma_islocked( void ) | |
145 | * | |
146 | * Purpose: Check if the ST-DMA is currently locked. | |
147 | * Note: Returned status is only valid if ints are disabled while calling and | |
148 | * as long as they remain disabled. | |
149 | * If called with ints enabled, status can change only from locked to | |
150 | * unlocked, because ints may not lock the ST-DMA. | |
151 | * | |
152 | * Inputs: none | |
153 | * | |
154 | * Returns: != 0 if locked, 0 otherwise | |
155 | * | |
156 | */ | |
157 | ||
158 | int stdma_islocked(void) | |
159 | { | |
160 | return stdma_locked; | |
161 | } | |
a3b2004a | 162 | EXPORT_SYMBOL(stdma_islocked); |
1da177e4 LT |
163 | |
164 | ||
165 | /* | |
166 | * Function: void stdma_init( void ) | |
167 | * | |
168 | * Purpose: Initialize the ST-DMA chip access controlling. | |
169 | * It sets up the interrupt and its service routine. The int is registered | |
170 | * as slow int, client devices have to live with that (no problem | |
171 | * currently). | |
172 | * | |
173 | * Inputs: none | |
174 | * | |
175 | * Return: nothing | |
176 | * | |
177 | */ | |
178 | ||
179 | void __init stdma_init(void) | |
180 | { | |
181 | stdma_isr = NULL; | |
5b8b4c3d GU |
182 | if (request_irq(IRQ_MFP_FDC, stdma_int, IRQ_TYPE_SLOW | IRQF_SHARED, |
183 | "ST-DMA: floppy/ACSI/IDE/Falcon-SCSI", stdma_int)) | |
184 | pr_err("Couldn't register ST-DMA interrupt\n"); | |
1da177e4 LT |
185 | } |
186 | ||
187 | ||
188 | /* | |
189 | * Function: void stdma_int() | |
190 | * | |
191 | * Purpose: The interrupt routine for the ST-DMA. It calls the isr | |
192 | * registered by stdma_lock(). | |
193 | * | |
194 | */ | |
195 | ||
2850bc27 | 196 | static irqreturn_t stdma_int(int irq, void *dummy) |
1da177e4 LT |
197 | { |
198 | if (stdma_isr) | |
2850bc27 | 199 | (*stdma_isr)(irq, stdma_isr_data); |
1da177e4 LT |
200 | return IRQ_HANDLED; |
201 | } |