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1/* SPDX-License-Identifier: GPL-2.0-only */
2/****************************************************************************
3 * Driver for Solarflare network controllers and boards
4 * Copyright 2005-2006 Fen Systems Ltd.
5 * Copyright 2006-2013 Solarflare Communications Inc.
6 */
7
8#ifndef EFX_IO_H
9#define EFX_IO_H
10
11#include <linux/io.h>
12#include <linux/spinlock.h>
13
14/**************************************************************************
15 *
16 * NIC register I/O
17 *
18 **************************************************************************
19 *
20 * Notes on locking strategy for the Falcon architecture:
21 *
22 * Many CSRs are very wide and cannot be read or written atomically.
23 * Writes from the host are buffered by the Bus Interface Unit (BIU)
24 * up to 128 bits. Whenever the host writes part of such a register,
25 * the BIU collects the written value and does not write to the
26 * underlying register until all 4 dwords have been written. A
27 * similar buffering scheme applies to host access to the NIC's 64-bit
28 * SRAM.
29 *
30 * Writes to different CSRs and 64-bit SRAM words must be serialised,
31 * since interleaved access can result in lost writes. We use
32 * efx_nic::biu_lock for this.
33 *
34 * We also serialise reads from 128-bit CSRs and SRAM with the same
35 * spinlock. This may not be necessary, but it doesn't really matter
36 * as there are no such reads on the fast path.
37 *
38 * The DMA descriptor pointers (RX_DESC_UPD and TX_DESC_UPD) are
39 * 128-bit but are special-cased in the BIU to avoid the need for
40 * locking in the host:
41 *
42 * - They are write-only.
43 * - The semantics of writing to these registers are such that
44 * replacing the low 96 bits with zero does not affect functionality.
45 * - If the host writes to the last dword address of such a register
46 * (i.e. the high 32 bits) the underlying register will always be
47 * written. If the collector and the current write together do not
48 * provide values for all 128 bits of the register, the low 96 bits
49 * will be written as zero.
50 * - If the host writes to the address of any other part of such a
51 * register while the collector already holds values for some other
52 * register, the write is discarded and the collector maintains its
53 * current state.
54 *
55 * The EF10 architecture exposes very few registers to the host and
56 * most of them are only 32 bits wide. The only exceptions are the MC
57 * doorbell register pair, which has its own latching, and
58 * TX_DESC_UPD, which works in a similar way to the Falcon
59 * architecture.
60 */
61
62#if BITS_PER_LONG == 64
63#define EFX_USE_QWORD_IO 1
64#endif
65
66/* Hardware issue requires that only 64-bit naturally aligned writes
67 * are seen by hardware. Its not strictly necessary to restrict to
68 * x86_64 arch, but done for safety since unusual write combining behaviour
69 * can break PIO.
70 */
71#ifdef CONFIG_X86_64
72/* PIO is a win only if write-combining is possible */
73#ifdef ioremap_wc
74#define EFX_USE_PIO 1
75#endif
76#endif
77
78static inline u32 efx_reg(struct efx_nic *efx, unsigned int reg)
79{
80 return efx->reg_base + reg;
81}
82
83#ifdef EFX_USE_QWORD_IO
84static inline void _efx_writeq(struct efx_nic *efx, __le64 value,
85 unsigned int reg)
86{
87 __raw_writeq((__force u64)value, efx->membase + reg);
88}
89static inline __le64 _efx_readq(struct efx_nic *efx, unsigned int reg)
90{
91 return (__force __le64)__raw_readq(efx->membase + reg);
92}
93#endif
94
95static inline void _efx_writed(struct efx_nic *efx, __le32 value,
96 unsigned int reg)
97{
98 __raw_writel((__force u32)value, efx->membase + reg);
99}
100static inline __le32 _efx_readd(struct efx_nic *efx, unsigned int reg)
101{
102 return (__force __le32)__raw_readl(efx->membase + reg);
103}
104
105/* Write a normal 128-bit CSR, locking as appropriate. */
106static inline void efx_writeo(struct efx_nic *efx, const efx_oword_t *value,
107 unsigned int reg)
108{
109 unsigned long flags __attribute__ ((unused));
110
111 netif_vdbg(efx, hw, efx->net_dev,
112 "writing register %x with " EFX_OWORD_FMT "\n", reg,
113 EFX_OWORD_VAL(*value));
114
115 spin_lock_irqsave(&efx->biu_lock, flags);
116#ifdef EFX_USE_QWORD_IO
117 _efx_writeq(efx, value->u64[0], reg + 0);
118 _efx_writeq(efx, value->u64[1], reg + 8);
119#else
120 _efx_writed(efx, value->u32[0], reg + 0);
121 _efx_writed(efx, value->u32[1], reg + 4);
122 _efx_writed(efx, value->u32[2], reg + 8);
123 _efx_writed(efx, value->u32[3], reg + 12);
124#endif
125 spin_unlock_irqrestore(&efx->biu_lock, flags);
126}
127
128/* Write 64-bit SRAM through the supplied mapping, locking as appropriate. */
129static inline void efx_sram_writeq(struct efx_nic *efx, void __iomem *membase,
130 const efx_qword_t *value, unsigned int index)
131{
132 unsigned int addr = index * sizeof(*value);
133 unsigned long flags __attribute__ ((unused));
134
135 netif_vdbg(efx, hw, efx->net_dev,
136 "writing SRAM address %x with " EFX_QWORD_FMT "\n",
137 addr, EFX_QWORD_VAL(*value));
138
139 spin_lock_irqsave(&efx->biu_lock, flags);
140#ifdef EFX_USE_QWORD_IO
141 __raw_writeq((__force u64)value->u64[0], membase + addr);
142#else
143 __raw_writel((__force u32)value->u32[0], membase + addr);
144 __raw_writel((__force u32)value->u32[1], membase + addr + 4);
145#endif
146 spin_unlock_irqrestore(&efx->biu_lock, flags);
147}
148
149/* Write a 32-bit CSR or the last dword of a special 128-bit CSR */
150static inline void efx_writed(struct efx_nic *efx, const efx_dword_t *value,
151 unsigned int reg)
152{
153 netif_vdbg(efx, hw, efx->net_dev,
154 "writing register %x with "EFX_DWORD_FMT"\n",
155 reg, EFX_DWORD_VAL(*value));
156
157 /* No lock required */
158 _efx_writed(efx, value->u32[0], reg);
159}
160
161/* Read a 128-bit CSR, locking as appropriate. */
162static inline void efx_reado(struct efx_nic *efx, efx_oword_t *value,
163 unsigned int reg)
164{
165 unsigned long flags __attribute__ ((unused));
166
167 spin_lock_irqsave(&efx->biu_lock, flags);
168 value->u32[0] = _efx_readd(efx, reg + 0);
169 value->u32[1] = _efx_readd(efx, reg + 4);
170 value->u32[2] = _efx_readd(efx, reg + 8);
171 value->u32[3] = _efx_readd(efx, reg + 12);
172 spin_unlock_irqrestore(&efx->biu_lock, flags);
173
174 netif_vdbg(efx, hw, efx->net_dev,
175 "read from register %x, got " EFX_OWORD_FMT "\n", reg,
176 EFX_OWORD_VAL(*value));
177}
178
179/* Read 64-bit SRAM through the supplied mapping, locking as appropriate. */
180static inline void efx_sram_readq(struct efx_nic *efx, void __iomem *membase,
181 efx_qword_t *value, unsigned int index)
182{
183 unsigned int addr = index * sizeof(*value);
184 unsigned long flags __attribute__ ((unused));
185
186 spin_lock_irqsave(&efx->biu_lock, flags);
187#ifdef EFX_USE_QWORD_IO
188 value->u64[0] = (__force __le64)__raw_readq(membase + addr);
189#else
190 value->u32[0] = (__force __le32)__raw_readl(membase + addr);
191 value->u32[1] = (__force __le32)__raw_readl(membase + addr + 4);
192#endif
193 spin_unlock_irqrestore(&efx->biu_lock, flags);
194
195 netif_vdbg(efx, hw, efx->net_dev,
196 "read from SRAM address %x, got "EFX_QWORD_FMT"\n",
197 addr, EFX_QWORD_VAL(*value));
198}
199
200/* Read a 32-bit CSR or SRAM */
201static inline void efx_readd(struct efx_nic *efx, efx_dword_t *value,
202 unsigned int reg)
203{
204 value->u32[0] = _efx_readd(efx, reg);
205 netif_vdbg(efx, hw, efx->net_dev,
206 "read from register %x, got "EFX_DWORD_FMT"\n",
207 reg, EFX_DWORD_VAL(*value));
208}
209
210/* Write a 128-bit CSR forming part of a table */
211static inline void
212efx_writeo_table(struct efx_nic *efx, const efx_oword_t *value,
213 unsigned int reg, unsigned int index)
214{
215 efx_writeo(efx, value, reg + index * sizeof(efx_oword_t));
216}
217
218/* Read a 128-bit CSR forming part of a table */
219static inline void efx_reado_table(struct efx_nic *efx, efx_oword_t *value,
220 unsigned int reg, unsigned int index)
221{
222 efx_reado(efx, value, reg + index * sizeof(efx_oword_t));
223}
224
225/* default VI stride (step between per-VI registers) is 8K on EF10 and
226 * 64K on EF100
227 */
228#define EFX_DEFAULT_VI_STRIDE 0x2000
229#define EF100_DEFAULT_VI_STRIDE 0x10000
230
231/* Calculate offset to page-mapped register */
232static inline unsigned int efx_paged_reg(struct efx_nic *efx, unsigned int page,
233 unsigned int reg)
234{
235 return page * efx->vi_stride + reg;
236}
237
238/* Write the whole of RX_DESC_UPD or TX_DESC_UPD */
239static inline void _efx_writeo_page(struct efx_nic *efx, efx_oword_t *value,
240 unsigned int reg, unsigned int page)
241{
242 reg = efx_paged_reg(efx, page, reg);
243
244 netif_vdbg(efx, hw, efx->net_dev,
245 "writing register %x with " EFX_OWORD_FMT "\n", reg,
246 EFX_OWORD_VAL(*value));
247
248#ifdef EFX_USE_QWORD_IO
249 _efx_writeq(efx, value->u64[0], reg + 0);
250 _efx_writeq(efx, value->u64[1], reg + 8);
251#else
252 _efx_writed(efx, value->u32[0], reg + 0);
253 _efx_writed(efx, value->u32[1], reg + 4);
254 _efx_writed(efx, value->u32[2], reg + 8);
255 _efx_writed(efx, value->u32[3], reg + 12);
256#endif
257}
258#define efx_writeo_page(efx, value, reg, page) \
259 _efx_writeo_page(efx, value, \
260 reg + \
261 BUILD_BUG_ON_ZERO((reg) != 0x830 && (reg) != 0xa10), \
262 page)
263
264/* Write a page-mapped 32-bit CSR (EVQ_RPTR, EVQ_TMR (EF10), or the
265 * high bits of RX_DESC_UPD or TX_DESC_UPD)
266 */
267static inline void
268_efx_writed_page(struct efx_nic *efx, const efx_dword_t *value,
269 unsigned int reg, unsigned int page)
270{
271 efx_writed(efx, value, efx_paged_reg(efx, page, reg));
272}
273#define efx_writed_page(efx, value, reg, page) \
274 _efx_writed_page(efx, value, \
275 reg + \
276 BUILD_BUG_ON_ZERO((reg) != 0x180 && \
277 (reg) != 0x200 && \
278 (reg) != 0x400 && \
279 (reg) != 0x420 && \
280 (reg) != 0x830 && \
281 (reg) != 0x83c && \
282 (reg) != 0xa18 && \
283 (reg) != 0xa1c), \
284 page)
285
286/* Write TIMER_COMMAND. This is a page-mapped 32-bit CSR, but a bug
287 * in the BIU means that writes to TIMER_COMMAND[0] invalidate the
288 * collector register.
289 */
290static inline void _efx_writed_page_locked(struct efx_nic *efx,
291 const efx_dword_t *value,
292 unsigned int reg,
293 unsigned int page)
294{
295 unsigned long flags __attribute__ ((unused));
296
297 if (page == 0) {
298 spin_lock_irqsave(&efx->biu_lock, flags);
299 efx_writed(efx, value, efx_paged_reg(efx, page, reg));
300 spin_unlock_irqrestore(&efx->biu_lock, flags);
301 } else {
302 efx_writed(efx, value, efx_paged_reg(efx, page, reg));
303 }
304}
305#define efx_writed_page_locked(efx, value, reg, page) \
306 _efx_writed_page_locked(efx, value, \
307 reg + BUILD_BUG_ON_ZERO((reg) != 0x420), \
308 page)
309
310#endif /* EFX_IO_H */