tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1/****************************************************************************
2 * Driver for Solarflare Solarstorm network controllers and boards
3 * Copyright 2005-2006 Fen Systems Ltd.
4 * Copyright 2006-2010 Solarflare Communications Inc.
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 *
23 * Notes on locking strategy:
24 *
25 * Most CSRs are 128-bit (oword) and therefore cannot be read or
26 * written atomically. Access from the host is buffered by the Bus
27 * Interface Unit (BIU). Whenever the host reads from the lowest
28 * address of such a register, or from the address of a different such
29 * register, the BIU latches the register's value. Subsequent reads
30 * from higher addresses of the same register will read the latched
31 * value. Whenever the host writes part of such a register, the BIU
32 * collects the written value and does not write to the underlying
33 * register until all 4 dwords have been written. A similar buffering
34 * scheme applies to host access to the NIC's 64-bit SRAM.
35 *
36 * Access to different CSRs and 64-bit SRAM words must be serialised,
37 * since interleaved access can result in lost writes or lost
38 * information from read-to-clear fields. We use efx_nic::biu_lock
39 * for this. (We could use separate locks for read and write, but
40 * this is not normally a performance bottleneck.)
41 *
42 * The DMA descriptor pointers (RX_DESC_UPD and TX_DESC_UPD) are
43 * 128-bit but are special-cased in the BIU to avoid the need for
44 * locking in the host:
45 *
46 * - They are write-only.
47 * - The semantics of writing to these registers are such that
48 * replacing the low 96 bits with zero does not affect functionality.
49 * - If the host writes to the last dword address of such a register
50 * (i.e. the high 32 bits) the underlying register will always be
51 * written. If the collector and the current write together do not
52 * provide values for all 128 bits of the register, the low 96 bits
53 * will be written as zero.
54 * - If the host writes to the address of any other part of such a
55 * register while the collector already holds values for some other
56 * register, the write is discarded and the collector maintains its
57 * current state.
58 */
59
60#if BITS_PER_LONG == 64
61#define EFX_USE_QWORD_IO 1
62#endif
63
64#ifdef EFX_USE_QWORD_IO
65static inline void _efx_writeq(struct efx_nic *efx, __le64 value,
66 unsigned int reg)
67{
68 __raw_writeq((__force u64)value, efx->membase + reg);
69}
70static inline __le64 _efx_readq(struct efx_nic *efx, unsigned int reg)
71{
72 return (__force __le64)__raw_readq(efx->membase + reg);
73}
74#endif
75
76static inline void _efx_writed(struct efx_nic *efx, __le32 value,
77 unsigned int reg)
78{
79 __raw_writel((__force u32)value, efx->membase + reg);
80}
81static inline __le32 _efx_readd(struct efx_nic *efx, unsigned int reg)
82{
83 return (__force __le32)__raw_readl(efx->membase + reg);
84}
85
86/* Write a normal 128-bit CSR, locking as appropriate. */
87static inline void efx_writeo(struct efx_nic *efx, efx_oword_t *value,
88 unsigned int reg)
89{
90 unsigned long flags __attribute__ ((unused));
91
92 netif_vdbg(efx, hw, efx->net_dev,
93 "writing register %x with " EFX_OWORD_FMT "\n", reg,
94 EFX_OWORD_VAL(*value));
95
96 spin_lock_irqsave(&efx->biu_lock, flags);
97#ifdef EFX_USE_QWORD_IO
98 _efx_writeq(efx, value->u64[0], reg + 0);
99 _efx_writeq(efx, value->u64[1], reg + 8);
100#else
101 _efx_writed(efx, value->u32[0], reg + 0);
102 _efx_writed(efx, value->u32[1], reg + 4);
103 _efx_writed(efx, value->u32[2], reg + 8);
104 _efx_writed(efx, value->u32[3], reg + 12);
105#endif
106 wmb();
107 mmiowb();
108 spin_unlock_irqrestore(&efx->biu_lock, flags);
109}
110
111/* Write 64-bit SRAM through the supplied mapping, locking as appropriate. */
112static inline void efx_sram_writeq(struct efx_nic *efx, void __iomem *membase,
113 efx_qword_t *value, unsigned int index)
114{
115 unsigned int addr = index * sizeof(*value);
116 unsigned long flags __attribute__ ((unused));
117
118 netif_vdbg(efx, hw, efx->net_dev,
119 "writing SRAM address %x with " EFX_QWORD_FMT "\n",
120 addr, EFX_QWORD_VAL(*value));
121
122 spin_lock_irqsave(&efx->biu_lock, flags);
123#ifdef EFX_USE_QWORD_IO
124 __raw_writeq((__force u64)value->u64[0], membase + addr);
125#else
126 __raw_writel((__force u32)value->u32[0], membase + addr);
127 __raw_writel((__force u32)value->u32[1], membase + addr + 4);
128#endif
129 wmb();
130 mmiowb();
131 spin_unlock_irqrestore(&efx->biu_lock, flags);
132}
133
134/* Write a 32-bit CSR or the last dword of a special 128-bit CSR */
135static inline void efx_writed(struct efx_nic *efx, efx_dword_t *value,
136 unsigned int reg)
137{
138 netif_vdbg(efx, hw, efx->net_dev,
139 "writing register %x with "EFX_DWORD_FMT"\n",
140 reg, EFX_DWORD_VAL(*value));
141
142 /* No lock required */
143 _efx_writed(efx, value->u32[0], reg);
144 wmb();
145}
146
147/* Read a 128-bit CSR, locking as appropriate. */
148static inline void efx_reado(struct efx_nic *efx, efx_oword_t *value,
149 unsigned int reg)
150{
151 unsigned long flags __attribute__ ((unused));
152
153 spin_lock_irqsave(&efx->biu_lock, flags);
154 value->u32[0] = _efx_readd(efx, reg + 0);
155 rmb();
156 value->u32[1] = _efx_readd(efx, reg + 4);
157 value->u32[2] = _efx_readd(efx, reg + 8);
158 value->u32[3] = _efx_readd(efx, reg + 12);
159 spin_unlock_irqrestore(&efx->biu_lock, flags);
160
161 netif_vdbg(efx, hw, efx->net_dev,
162 "read from register %x, got " EFX_OWORD_FMT "\n", reg,
163 EFX_OWORD_VAL(*value));
164}
165
166/* Read 64-bit SRAM through the supplied mapping, locking as appropriate. */
167static inline void efx_sram_readq(struct efx_nic *efx, void __iomem *membase,
168 efx_qword_t *value, unsigned int index)
169{
170 unsigned int addr = index * sizeof(*value);
171 unsigned long flags __attribute__ ((unused));
172
173 spin_lock_irqsave(&efx->biu_lock, flags);
174#ifdef EFX_USE_QWORD_IO
175 value->u64[0] = (__force __le64)__raw_readq(membase + addr);
176#else
177 value->u32[0] = (__force __le32)__raw_readl(membase + addr);
178 rmb();
179 value->u32[1] = (__force __le32)__raw_readl(membase + addr + 4);
180#endif
181 spin_unlock_irqrestore(&efx->biu_lock, flags);
182
183 netif_vdbg(efx, hw, efx->net_dev,
184 "read from SRAM address %x, got "EFX_QWORD_FMT"\n",
185 addr, EFX_QWORD_VAL(*value));
186}
187
188/* Read a 32-bit CSR or SRAM */
189static inline void efx_readd(struct efx_nic *efx, efx_dword_t *value,
190 unsigned int reg)
191{
192 value->u32[0] = _efx_readd(efx, reg);
193 netif_vdbg(efx, hw, efx->net_dev,
194 "read from register %x, got "EFX_DWORD_FMT"\n",
195 reg, EFX_DWORD_VAL(*value));
196}
197
198/* Write a 128-bit CSR forming part of a table */
199static inline void efx_writeo_table(struct efx_nic *efx, efx_oword_t *value,
200 unsigned int reg, unsigned int index)
201{
202 efx_writeo(efx, value, reg + index * sizeof(efx_oword_t));
203}
204
205/* Read a 128-bit CSR forming part of a table */
206static inline void efx_reado_table(struct efx_nic *efx, efx_oword_t *value,
207 unsigned int reg, unsigned int index)
208{
209 efx_reado(efx, value, reg + index * sizeof(efx_oword_t));
210}
211
212/* Write a 32-bit CSR forming part of a table, or 32-bit SRAM */
213static inline void efx_writed_table(struct efx_nic *efx, efx_dword_t *value,
214 unsigned int reg, unsigned int index)
215{
216 efx_writed(efx, value, reg + index * sizeof(efx_oword_t));
217}
218
219/* Read a 32-bit CSR forming part of a table, or 32-bit SRAM */
220static inline void efx_readd_table(struct efx_nic *efx, efx_dword_t *value,
221 unsigned int reg, unsigned int index)
222{
223 efx_readd(efx, value, reg + index * sizeof(efx_dword_t));
224}
225
226/* Page-mapped register block size */
227#define EFX_PAGE_BLOCK_SIZE 0x2000
228
229/* Calculate offset to page-mapped register block */
230#define EFX_PAGED_REG(page, reg) \
231 ((page) * EFX_PAGE_BLOCK_SIZE + (reg))
232
233/* Write the whole of RX_DESC_UPD or TX_DESC_UPD */
234static inline void _efx_writeo_page(struct efx_nic *efx, efx_oword_t *value,
235 unsigned int reg, unsigned int page)
236{
237 reg = EFX_PAGED_REG(page, reg);
238
239 netif_vdbg(efx, hw, efx->net_dev,
240 "writing register %x with " EFX_OWORD_FMT "\n", reg,
241 EFX_OWORD_VAL(*value));
242
243#ifdef EFX_USE_QWORD_IO
244 _efx_writeq(efx, value->u64[0], reg + 0);
245 _efx_writeq(efx, value->u64[1], reg + 8);
246#else
247 _efx_writed(efx, value->u32[0], reg + 0);
248 _efx_writed(efx, value->u32[1], reg + 4);
249 _efx_writed(efx, value->u32[2], reg + 8);
250 _efx_writed(efx, value->u32[3], reg + 12);
251#endif
252 wmb();
253}
254#define efx_writeo_page(efx, value, reg, page) \
255 _efx_writeo_page(efx, value, \
256 reg + \
257 BUILD_BUG_ON_ZERO((reg) != 0x830 && (reg) != 0xa10), \
258 page)
259
260/* Write a page-mapped 32-bit CSR (EVQ_RPTR or the high bits of
261 * RX_DESC_UPD or TX_DESC_UPD)
262 */
263static inline void _efx_writed_page(struct efx_nic *efx, efx_dword_t *value,
264 unsigned int reg, unsigned int page)
265{
266 efx_writed(efx, value, EFX_PAGED_REG(page, reg));
267}
268#define efx_writed_page(efx, value, reg, page) \
269 _efx_writed_page(efx, value, \
270 reg + \
271 BUILD_BUG_ON_ZERO((reg) != 0x400 && (reg) != 0x83c \
272 && (reg) != 0xa1c), \
273 page)
274
275/* Write TIMER_COMMAND. This is a page-mapped 32-bit CSR, but a bug
276 * in the BIU means that writes to TIMER_COMMAND[0] invalidate the
277 * collector register.
278 */
279static inline void _efx_writed_page_locked(struct efx_nic *efx,
280 efx_dword_t *value,
281 unsigned int reg,
282 unsigned int page)
283{
284 unsigned long flags __attribute__ ((unused));
285
286 if (page == 0) {
287 spin_lock_irqsave(&efx->biu_lock, flags);
288 efx_writed(efx, value, EFX_PAGED_REG(page, reg));
289 spin_unlock_irqrestore(&efx->biu_lock, flags);
290 } else {
291 efx_writed(efx, value, EFX_PAGED_REG(page, reg));
292 }
293}
294#define efx_writed_page_locked(efx, value, reg, page) \
295 _efx_writed_page_locked(efx, value, \
296 reg + BUILD_BUG_ON_ZERO((reg) != 0x420), \
297 page)
298
299#endif /* EFX_IO_H */