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12d00cad 1/****************************************************************************
f7a6d2c4 2 * Driver for Solarflare network controllers and boards
12d00cad 3 * Copyright 2005-2006 Fen Systems Ltd.
f7a6d2c4 4 * Copyright 2006-2013 Solarflare Communications Inc.
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5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation, incorporated herein by reference.
9 */
10
11#ifndef EFX_IO_H
12#define EFX_IO_H
13
14#include <linux/io.h>
15#include <linux/spinlock.h>
16
17/**************************************************************************
18 *
19 * NIC register I/O
20 *
21 **************************************************************************
22 *
9c517165 23 * Notes on locking strategy for the Falcon architecture:
12d00cad 24 *
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25 * Many CSRs are very wide and cannot be read or written atomically.
26 * Writes from the host are buffered by the Bus Interface Unit (BIU)
27 * up to 128 bits. Whenever the host writes part of such a register,
28 * the BIU collects the written value and does not write to the
29 * underlying register until all 4 dwords have been written. A
30 * similar buffering scheme applies to host access to the NIC's 64-bit
31 * SRAM.
12d00cad 32 *
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33 * Writes to different CSRs and 64-bit SRAM words must be serialised,
34 * since interleaved access can result in lost writes. We use
35 * efx_nic::biu_lock for this.
36 *
37 * We also serialise reads from 128-bit CSRs and SRAM with the same
38 * spinlock. This may not be necessary, but it doesn't really matter
39 * as there are no such reads on the fast path.
12d00cad 40 *
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41 * The DMA descriptor pointers (RX_DESC_UPD and TX_DESC_UPD) are
42 * 128-bit but are special-cased in the BIU to avoid the need for
43 * locking in the host:
12d00cad 44 *
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45 * - They are write-only.
46 * - The semantics of writing to these registers are such that
47 * replacing the low 96 bits with zero does not affect functionality.
48 * - If the host writes to the last dword address of such a register
49 * (i.e. the high 32 bits) the underlying register will always be
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50 * written. If the collector and the current write together do not
51 * provide values for all 128 bits of the register, the low 96 bits
52 * will be written as zero.
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53 * - If the host writes to the address of any other part of such a
54 * register while the collector already holds values for some other
55 * register, the write is discarded and the collector maintains its
56 * current state.
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57 *
58 * The EF10 architecture exposes very few registers to the host and
59 * most of them are only 32 bits wide. The only exceptions are the MC
60 * doorbell register pair, which has its own latching, and
61 * TX_DESC_UPD, which works in a similar way to the Falcon
62 * architecture.
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63 */
64
65#if BITS_PER_LONG == 64
66#define EFX_USE_QWORD_IO 1
67#endif
68
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69/* PIO is a win only if write-combining is possible */
70#ifdef ARCH_HAS_IOREMAP_WC
71#define EFX_USE_PIO 1
72#endif
73
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74#ifdef EFX_USE_QWORD_IO
75static inline void _efx_writeq(struct efx_nic *efx, __le64 value,
76 unsigned int reg)
77{
78 __raw_writeq((__force u64)value, efx->membase + reg);
79}
80static inline __le64 _efx_readq(struct efx_nic *efx, unsigned int reg)
81{
82 return (__force __le64)__raw_readq(efx->membase + reg);
83}
84#endif
85
86static inline void _efx_writed(struct efx_nic *efx, __le32 value,
87 unsigned int reg)
88{
89 __raw_writel((__force u32)value, efx->membase + reg);
90}
91static inline __le32 _efx_readd(struct efx_nic *efx, unsigned int reg)
92{
93 return (__force __le32)__raw_readl(efx->membase + reg);
94}
95
9f2f6cd0 96/* Write a normal 128-bit CSR, locking as appropriate. */
5383825c 97static inline void efx_writeo(struct efx_nic *efx, const efx_oword_t *value,
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98 unsigned int reg)
99{
100 unsigned long flags __attribute__ ((unused));
101
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102 netif_vdbg(efx, hw, efx->net_dev,
103 "writing register %x with " EFX_OWORD_FMT "\n", reg,
104 EFX_OWORD_VAL(*value));
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105
106 spin_lock_irqsave(&efx->biu_lock, flags);
107#ifdef EFX_USE_QWORD_IO
108 _efx_writeq(efx, value->u64[0], reg + 0);
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109 _efx_writeq(efx, value->u64[1], reg + 8);
110#else
111 _efx_writed(efx, value->u32[0], reg + 0);
112 _efx_writed(efx, value->u32[1], reg + 4);
113 _efx_writed(efx, value->u32[2], reg + 8);
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114 _efx_writed(efx, value->u32[3], reg + 12);
115#endif
116 mmiowb();
117 spin_unlock_irqrestore(&efx->biu_lock, flags);
118}
119
9f2f6cd0 120/* Write 64-bit SRAM through the supplied mapping, locking as appropriate. */
12d00cad 121static inline void efx_sram_writeq(struct efx_nic *efx, void __iomem *membase,
5383825c 122 const efx_qword_t *value, unsigned int index)
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123{
124 unsigned int addr = index * sizeof(*value);
125 unsigned long flags __attribute__ ((unused));
126
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127 netif_vdbg(efx, hw, efx->net_dev,
128 "writing SRAM address %x with " EFX_QWORD_FMT "\n",
129 addr, EFX_QWORD_VAL(*value));
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130
131 spin_lock_irqsave(&efx->biu_lock, flags);
132#ifdef EFX_USE_QWORD_IO
133 __raw_writeq((__force u64)value->u64[0], membase + addr);
134#else
135 __raw_writel((__force u32)value->u32[0], membase + addr);
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136 __raw_writel((__force u32)value->u32[1], membase + addr + 4);
137#endif
138 mmiowb();
139 spin_unlock_irqrestore(&efx->biu_lock, flags);
140}
141
9f2f6cd0 142/* Write a 32-bit CSR or the last dword of a special 128-bit CSR */
5383825c 143static inline void efx_writed(struct efx_nic *efx, const efx_dword_t *value,
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144 unsigned int reg)
145{
62776d03 146 netif_vdbg(efx, hw, efx->net_dev,
9f2f6cd0 147 "writing register %x with "EFX_DWORD_FMT"\n",
62776d03 148 reg, EFX_DWORD_VAL(*value));
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149
150 /* No lock required */
151 _efx_writed(efx, value->u32[0], reg);
152}
153
9f2f6cd0 154/* Read a 128-bit CSR, locking as appropriate. */
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155static inline void efx_reado(struct efx_nic *efx, efx_oword_t *value,
156 unsigned int reg)
157{
158 unsigned long flags __attribute__ ((unused));
159
160 spin_lock_irqsave(&efx->biu_lock, flags);
161 value->u32[0] = _efx_readd(efx, reg + 0);
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162 value->u32[1] = _efx_readd(efx, reg + 4);
163 value->u32[2] = _efx_readd(efx, reg + 8);
164 value->u32[3] = _efx_readd(efx, reg + 12);
165 spin_unlock_irqrestore(&efx->biu_lock, flags);
166
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167 netif_vdbg(efx, hw, efx->net_dev,
168 "read from register %x, got " EFX_OWORD_FMT "\n", reg,
169 EFX_OWORD_VAL(*value));
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170}
171
9f2f6cd0 172/* Read 64-bit SRAM through the supplied mapping, locking as appropriate. */
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173static inline void efx_sram_readq(struct efx_nic *efx, void __iomem *membase,
174 efx_qword_t *value, unsigned int index)
175{
176 unsigned int addr = index * sizeof(*value);
177 unsigned long flags __attribute__ ((unused));
178
179 spin_lock_irqsave(&efx->biu_lock, flags);
180#ifdef EFX_USE_QWORD_IO
181 value->u64[0] = (__force __le64)__raw_readq(membase + addr);
182#else
183 value->u32[0] = (__force __le32)__raw_readl(membase + addr);
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184 value->u32[1] = (__force __le32)__raw_readl(membase + addr + 4);
185#endif
186 spin_unlock_irqrestore(&efx->biu_lock, flags);
187
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188 netif_vdbg(efx, hw, efx->net_dev,
189 "read from SRAM address %x, got "EFX_QWORD_FMT"\n",
190 addr, EFX_QWORD_VAL(*value));
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191}
192
9f2f6cd0 193/* Read a 32-bit CSR or SRAM */
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194static inline void efx_readd(struct efx_nic *efx, efx_dword_t *value,
195 unsigned int reg)
196{
197 value->u32[0] = _efx_readd(efx, reg);
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198 netif_vdbg(efx, hw, efx->net_dev,
199 "read from register %x, got "EFX_DWORD_FMT"\n",
200 reg, EFX_DWORD_VAL(*value));
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201}
202
9f2f6cd0 203/* Write a 128-bit CSR forming part of a table */
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204static inline void
205efx_writeo_table(struct efx_nic *efx, const efx_oword_t *value,
206 unsigned int reg, unsigned int index)
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207{
208 efx_writeo(efx, value, reg + index * sizeof(efx_oword_t));
209}
210
9f2f6cd0 211/* Read a 128-bit CSR forming part of a table */
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212static inline void efx_reado_table(struct efx_nic *efx, efx_oword_t *value,
213 unsigned int reg, unsigned int index)
214{
215 efx_reado(efx, value, reg + index * sizeof(efx_oword_t));
216}
217
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218/* Page size used as step between per-VI registers */
219#define EFX_VI_PAGE_SIZE 0x2000
12d00cad 220
64a27752 221/* Calculate offset to page-mapped register */
12d00cad 222#define EFX_PAGED_REG(page, reg) \
64a27752 223 ((page) * EFX_VI_PAGE_SIZE + (reg))
12d00cad 224
9f2f6cd0 225/* Write the whole of RX_DESC_UPD or TX_DESC_UPD */
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226static inline void _efx_writeo_page(struct efx_nic *efx, efx_oword_t *value,
227 unsigned int reg, unsigned int page)
12d00cad 228{
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229 reg = EFX_PAGED_REG(page, reg);
230
231 netif_vdbg(efx, hw, efx->net_dev,
232 "writing register %x with " EFX_OWORD_FMT "\n", reg,
233 EFX_OWORD_VAL(*value));
234
235#ifdef EFX_USE_QWORD_IO
236 _efx_writeq(efx, value->u64[0], reg + 0);
483f97f8 237 _efx_writeq(efx, value->u64[1], reg + 8);
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238#else
239 _efx_writed(efx, value->u32[0], reg + 0);
240 _efx_writed(efx, value->u32[1], reg + 4);
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241 _efx_writed(efx, value->u32[2], reg + 8);
242 _efx_writed(efx, value->u32[3], reg + 12);
483f97f8 243#endif
12d00cad 244}
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245#define efx_writeo_page(efx, value, reg, page) \
246 _efx_writeo_page(efx, value, \
247 reg + \
248 BUILD_BUG_ON_ZERO((reg) != 0x830 && (reg) != 0xa10), \
249 page)
12d00cad 250
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251/* Write a page-mapped 32-bit CSR (EVQ_RPTR, EVQ_TMR (EF10), or the
252 * high bits of RX_DESC_UPD or TX_DESC_UPD)
9f2f6cd0 253 */
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254static inline void
255_efx_writed_page(struct efx_nic *efx, const efx_dword_t *value,
256 unsigned int reg, unsigned int page)
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257{
258 efx_writed(efx, value, EFX_PAGED_REG(page, reg));
259}
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260#define efx_writed_page(efx, value, reg, page) \
261 _efx_writed_page(efx, value, \
262 reg + \
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263 BUILD_BUG_ON_ZERO((reg) != 0x400 && \
264 (reg) != 0x420 && \
265 (reg) != 0x830 && \
266 (reg) != 0x83c && \
267 (reg) != 0xa18 && \
268 (reg) != 0xa1c), \
1a29cc40 269 page)
12d00cad 270
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271/* Write TIMER_COMMAND. This is a page-mapped 32-bit CSR, but a bug
272 * in the BIU means that writes to TIMER_COMMAND[0] invalidate the
273 * collector register.
274 */
1a29cc40 275static inline void _efx_writed_page_locked(struct efx_nic *efx,
5383825c 276 const efx_dword_t *value,
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277 unsigned int reg,
278 unsigned int page)
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279{
280 unsigned long flags __attribute__ ((unused));
281
282 if (page == 0) {
283 spin_lock_irqsave(&efx->biu_lock, flags);
284 efx_writed(efx, value, EFX_PAGED_REG(page, reg));
285 spin_unlock_irqrestore(&efx->biu_lock, flags);
286 } else {
287 efx_writed(efx, value, EFX_PAGED_REG(page, reg));
288 }
289}
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290#define efx_writed_page_locked(efx, value, reg, page) \
291 _efx_writed_page_locked(efx, value, \
292 reg + BUILD_BUG_ON_ZERO((reg) != 0x420), \
293 page)
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294
295#endif /* EFX_IO_H */