1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * arch/sh/boards/mach-x3proto/ilsel.c |
4 | * |
5 | * Helper routines for SH-X3 proto board ILSEL. |
6 | * |
7 | * Copyright (C) 2007 - 2010 Paul Mundt |
8 | */ |
9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
10 | |
11 | #include <linux/init.h> |
12 | #include <linux/kernel.h> |
13 | #include <linux/module.h> |
14 | #include <linux/bitmap.h> |
15 | #include <linux/io.h> |
16 | #include <mach/ilsel.h> |
17 | |
18 | /* |
19 | * ILSEL is split across: |
20 | * |
21 | * ILSEL0 - 0xb8100004 [ Levels 1 - 4 ] |
22 | * ILSEL1 - 0xb8100006 [ Levels 5 - 8 ] |
23 | * ILSEL2 - 0xb8100008 [ Levels 9 - 12 ] |
24 | * ILSEL3 - 0xb810000a [ Levels 13 - 15 ] |
25 | * |
26 | * With each level being relative to an ilsel_source_t. |
27 | */ |
28 | #define ILSEL_BASE 0xb8100004 |
29 | #define ILSEL_LEVELS 15 |
30 | |
31 | /* |
32 | * ILSEL level map, in descending order from the highest level down. |
33 | * |
34 | * Supported levels are 1 - 15 spread across ILSEL0 - ILSEL4, mapping |
35 | * directly to IRLs. As the IRQs are numbered in reverse order relative |
36 | * to the interrupt level, the level map is carefully managed to ensure a |
37 | * 1:1 mapping between the bit position and the IRQ number. |
38 | * |
39 | * This careful constructions allows ilsel_enable*() to be referenced |
40 | * directly for hooking up an ILSEL set and getting back an IRQ which can |
41 | * subsequently be used for internal accounting in the (optional) disable |
42 | * path. |
43 | */ |
44 | static unsigned long ilsel_level_map; |
45 | |
46 | static inline unsigned int ilsel_offset(unsigned int bit) |
47 | { |
48 | return ILSEL_LEVELS - bit - 1; |
49 | } |
50 | |
51 | static inline unsigned long mk_ilsel_addr(unsigned int bit) |
52 | { |
53 | return ILSEL_BASE + ((ilsel_offset(bit) >> 1) & ~0x1); |
54 | } |
55 | |
56 | static inline unsigned int mk_ilsel_shift(unsigned int bit) |
57 | { |
58 | return (ilsel_offset(bit) & 0x3) << 2; |
59 | } |
60 | |
61 | static void __ilsel_enable(ilsel_source_t set, unsigned int bit) |
62 | { |
63 | unsigned int tmp, shift; |
64 | unsigned long addr; |
65 | |
66 | pr_notice("enabling ILSEL set %d\n" , set); |
67 | |
68 | addr = mk_ilsel_addr(bit); |
69 | shift = mk_ilsel_shift(bit); |
70 | |
71 | pr_debug("%s: bit#%d: addr - 0x%08lx (shift %d, set %d)\n" , |
72 | __func__, bit, addr, shift, set); |
73 | |
74 | tmp = __raw_readw(addr); |
75 | tmp &= ~(0xf << shift); |
76 | tmp |= set << shift; |
77 | __raw_writew(val: tmp, addr); |
78 | } |
79 | |
80 | /** |
81 | * ilsel_enable - Enable an ILSEL set. |
82 | * @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h). |
83 | * |
84 | * Enables a given non-aliased ILSEL source (<= ILSEL_KEY) at the highest |
85 | * available interrupt level. Callers should take care to order callsites |
86 | * noting descending interrupt levels. Aliasing FPGA and external board |
87 | * IRQs need to use ilsel_enable_fixed(). |
88 | * |
89 | * The return value is an IRQ number that can later be taken down with |
90 | * ilsel_disable(). |
91 | */ |
92 | int ilsel_enable(ilsel_source_t set) |
93 | { |
94 | unsigned int bit; |
95 | |
96 | if (unlikely(set > ILSEL_KEY)) { |
97 | pr_err("Aliased sources must use ilsel_enable_fixed()\n" ); |
98 | return -EINVAL; |
99 | } |
100 | |
101 | do { |
102 | bit = find_first_zero_bit(addr: &ilsel_level_map, ILSEL_LEVELS); |
103 | } while (test_and_set_bit(nr: bit, addr: &ilsel_level_map)); |
104 | |
105 | __ilsel_enable(set, bit); |
106 | |
107 | return bit; |
108 | } |
109 | EXPORT_SYMBOL_GPL(ilsel_enable); |
110 | |
111 | /** |
112 | * ilsel_enable_fixed - Enable an ILSEL set at a fixed interrupt level |
113 | * @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h). |
114 | * @level: Interrupt level (1 - 15) |
115 | * |
116 | * Enables a given ILSEL source at a fixed interrupt level. Necessary |
117 | * both for level reservation as well as for aliased sources that only |
118 | * exist on special ILSEL#s. |
119 | * |
120 | * Returns an IRQ number (as ilsel_enable()). |
121 | */ |
122 | int ilsel_enable_fixed(ilsel_source_t set, unsigned int level) |
123 | { |
124 | unsigned int bit = ilsel_offset(bit: level - 1); |
125 | |
126 | if (test_and_set_bit(nr: bit, addr: &ilsel_level_map)) |
127 | return -EBUSY; |
128 | |
129 | __ilsel_enable(set, bit); |
130 | |
131 | return bit; |
132 | } |
133 | EXPORT_SYMBOL_GPL(ilsel_enable_fixed); |
134 | |
135 | /** |
136 | * ilsel_disable - Disable an ILSEL set |
137 | * @irq: Bit position for ILSEL set value (retval from enable routines) |
138 | * |
139 | * Disable a previously enabled ILSEL set. |
140 | */ |
141 | void ilsel_disable(unsigned int irq) |
142 | { |
143 | unsigned long addr; |
144 | unsigned int tmp; |
145 | |
146 | pr_notice("disabling ILSEL set %d\n" , irq); |
147 | |
148 | addr = mk_ilsel_addr(bit: irq); |
149 | |
150 | tmp = __raw_readw(addr); |
151 | tmp &= ~(0xf << mk_ilsel_shift(bit: irq)); |
152 | __raw_writew(val: tmp, addr); |
153 | |
154 | clear_bit(nr: irq, addr: &ilsel_level_map); |
155 | } |
156 | EXPORT_SYMBOL_GPL(ilsel_disable); |
157 | |