xref: /linux/drivers/net/ethernet/sfc/falcon/io.h (revision 75bf465f0bc33e9b776a46d6a1b9b990f5fb7c37)
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 EF4_IO_H
9 #define EF4_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  * ef4_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 EF4_USE_QWORD_IO 1
64 #endif
65 
66 #ifdef EF4_USE_QWORD_IO
_ef4_writeq(struct ef4_nic * efx,__le64 value,unsigned int reg)67 static inline void _ef4_writeq(struct ef4_nic *efx, __le64 value,
68 				  unsigned int reg)
69 {
70 	__raw_writeq((__force u64)value, efx->membase + reg);
71 }
_ef4_readq(struct ef4_nic * efx,unsigned int reg)72 static inline __le64 _ef4_readq(struct ef4_nic *efx, unsigned int reg)
73 {
74 	return (__force __le64)__raw_readq(efx->membase + reg);
75 }
76 #endif
77 
_ef4_writed(struct ef4_nic * efx,__le32 value,unsigned int reg)78 static inline void _ef4_writed(struct ef4_nic *efx, __le32 value,
79 				  unsigned int reg)
80 {
81 	__raw_writel((__force u32)value, efx->membase + reg);
82 }
_ef4_readd(struct ef4_nic * efx,unsigned int reg)83 static inline __le32 _ef4_readd(struct ef4_nic *efx, unsigned int reg)
84 {
85 	return (__force __le32)__raw_readl(efx->membase + reg);
86 }
87 
88 /* Write a normal 128-bit CSR, locking as appropriate. */
ef4_writeo(struct ef4_nic * efx,const ef4_oword_t * value,unsigned int reg)89 static inline void ef4_writeo(struct ef4_nic *efx, const ef4_oword_t *value,
90 			      unsigned int reg)
91 {
92 	unsigned long flags __attribute__ ((unused));
93 
94 	netif_vdbg(efx, hw, efx->net_dev,
95 		   "writing register %x with " EF4_OWORD_FMT "\n", reg,
96 		   EF4_OWORD_VAL(*value));
97 
98 	spin_lock_irqsave(&efx->biu_lock, flags);
99 #ifdef EF4_USE_QWORD_IO
100 	_ef4_writeq(efx, value->u64[0], reg + 0);
101 	_ef4_writeq(efx, value->u64[1], reg + 8);
102 #else
103 	_ef4_writed(efx, value->u32[0], reg + 0);
104 	_ef4_writed(efx, value->u32[1], reg + 4);
105 	_ef4_writed(efx, value->u32[2], reg + 8);
106 	_ef4_writed(efx, value->u32[3], reg + 12);
107 #endif
108 	spin_unlock_irqrestore(&efx->biu_lock, flags);
109 }
110 
111 /* Write 64-bit SRAM through the supplied mapping, locking as appropriate. */
ef4_sram_writeq(struct ef4_nic * efx,void __iomem * membase,const ef4_qword_t * value,unsigned int index)112 static inline void ef4_sram_writeq(struct ef4_nic *efx, void __iomem *membase,
113 				   const ef4_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 " EF4_QWORD_FMT "\n",
120 		   addr, EF4_QWORD_VAL(*value));
121 
122 	spin_lock_irqsave(&efx->biu_lock, flags);
123 #ifdef EF4_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 	spin_unlock_irqrestore(&efx->biu_lock, flags);
130 }
131 
132 /* Write a 32-bit CSR or the last dword of a special 128-bit CSR */
ef4_writed(struct ef4_nic * efx,const ef4_dword_t * value,unsigned int reg)133 static inline void ef4_writed(struct ef4_nic *efx, const ef4_dword_t *value,
134 			      unsigned int reg)
135 {
136 	netif_vdbg(efx, hw, efx->net_dev,
137 		   "writing register %x with "EF4_DWORD_FMT"\n",
138 		   reg, EF4_DWORD_VAL(*value));
139 
140 	/* No lock required */
141 	_ef4_writed(efx, value->u32[0], reg);
142 }
143 
144 /* Read a 128-bit CSR, locking as appropriate. */
ef4_reado(struct ef4_nic * efx,ef4_oword_t * value,unsigned int reg)145 static inline void ef4_reado(struct ef4_nic *efx, ef4_oword_t *value,
146 			     unsigned int reg)
147 {
148 	unsigned long flags __attribute__ ((unused));
149 
150 	spin_lock_irqsave(&efx->biu_lock, flags);
151 	value->u32[0] = _ef4_readd(efx, reg + 0);
152 	value->u32[1] = _ef4_readd(efx, reg + 4);
153 	value->u32[2] = _ef4_readd(efx, reg + 8);
154 	value->u32[3] = _ef4_readd(efx, reg + 12);
155 	spin_unlock_irqrestore(&efx->biu_lock, flags);
156 
157 	netif_vdbg(efx, hw, efx->net_dev,
158 		   "read from register %x, got " EF4_OWORD_FMT "\n", reg,
159 		   EF4_OWORD_VAL(*value));
160 }
161 
162 /* Read 64-bit SRAM through the supplied mapping, locking as appropriate. */
ef4_sram_readq(struct ef4_nic * efx,void __iomem * membase,ef4_qword_t * value,unsigned int index)163 static inline void ef4_sram_readq(struct ef4_nic *efx, void __iomem *membase,
164 				  ef4_qword_t *value, unsigned int index)
165 {
166 	unsigned int addr = index * sizeof(*value);
167 	unsigned long flags __attribute__ ((unused));
168 
169 	spin_lock_irqsave(&efx->biu_lock, flags);
170 #ifdef EF4_USE_QWORD_IO
171 	value->u64[0] = (__force __le64)__raw_readq(membase + addr);
172 #else
173 	value->u32[0] = (__force __le32)__raw_readl(membase + addr);
174 	value->u32[1] = (__force __le32)__raw_readl(membase + addr + 4);
175 #endif
176 	spin_unlock_irqrestore(&efx->biu_lock, flags);
177 
178 	netif_vdbg(efx, hw, efx->net_dev,
179 		   "read from SRAM address %x, got "EF4_QWORD_FMT"\n",
180 		   addr, EF4_QWORD_VAL(*value));
181 }
182 
183 /* Read a 32-bit CSR or SRAM */
ef4_readd(struct ef4_nic * efx,ef4_dword_t * value,unsigned int reg)184 static inline void ef4_readd(struct ef4_nic *efx, ef4_dword_t *value,
185 				unsigned int reg)
186 {
187 	value->u32[0] = _ef4_readd(efx, reg);
188 	netif_vdbg(efx, hw, efx->net_dev,
189 		   "read from register %x, got "EF4_DWORD_FMT"\n",
190 		   reg, EF4_DWORD_VAL(*value));
191 }
192 
193 /* Write a 128-bit CSR forming part of a table */
194 static inline void
ef4_writeo_table(struct ef4_nic * efx,const ef4_oword_t * value,unsigned int reg,unsigned int index)195 ef4_writeo_table(struct ef4_nic *efx, const ef4_oword_t *value,
196 		 unsigned int reg, unsigned int index)
197 {
198 	ef4_writeo(efx, value, reg + index * sizeof(ef4_oword_t));
199 }
200 
201 /* Read a 128-bit CSR forming part of a table */
ef4_reado_table(struct ef4_nic * efx,ef4_oword_t * value,unsigned int reg,unsigned int index)202 static inline void ef4_reado_table(struct ef4_nic *efx, ef4_oword_t *value,
203 				     unsigned int reg, unsigned int index)
204 {
205 	ef4_reado(efx, value, reg + index * sizeof(ef4_oword_t));
206 }
207 
208 /* Page size used as step between per-VI registers */
209 #define EF4_VI_PAGE_SIZE 0x2000
210 
211 /* Calculate offset to page-mapped register */
212 #define EF4_PAGED_REG(page, reg) \
213 	((page) * EF4_VI_PAGE_SIZE + (reg))
214 
215 /* Write the whole of RX_DESC_UPD or TX_DESC_UPD */
_ef4_writeo_page(struct ef4_nic * efx,ef4_oword_t * value,unsigned int reg,unsigned int page)216 static inline void _ef4_writeo_page(struct ef4_nic *efx, ef4_oword_t *value,
217 				    unsigned int reg, unsigned int page)
218 {
219 	reg = EF4_PAGED_REG(page, reg);
220 
221 	netif_vdbg(efx, hw, efx->net_dev,
222 		   "writing register %x with " EF4_OWORD_FMT "\n", reg,
223 		   EF4_OWORD_VAL(*value));
224 
225 #ifdef EF4_USE_QWORD_IO
226 	_ef4_writeq(efx, value->u64[0], reg + 0);
227 	_ef4_writeq(efx, value->u64[1], reg + 8);
228 #else
229 	_ef4_writed(efx, value->u32[0], reg + 0);
230 	_ef4_writed(efx, value->u32[1], reg + 4);
231 	_ef4_writed(efx, value->u32[2], reg + 8);
232 	_ef4_writed(efx, value->u32[3], reg + 12);
233 #endif
234 }
235 #define ef4_writeo_page(efx, value, reg, page)				\
236 	_ef4_writeo_page(efx, value,					\
237 			 reg +						\
238 			 BUILD_BUG_ON_ZERO((reg) != 0x830 && (reg) != 0xa10), \
239 			 page)
240 
241 /* Write a page-mapped 32-bit CSR (EVQ_RPTR, EVQ_TMR (EF10), or the
242  * high bits of RX_DESC_UPD or TX_DESC_UPD)
243  */
244 static inline void
_ef4_writed_page(struct ef4_nic * efx,const ef4_dword_t * value,unsigned int reg,unsigned int page)245 _ef4_writed_page(struct ef4_nic *efx, const ef4_dword_t *value,
246 		 unsigned int reg, unsigned int page)
247 {
248 	ef4_writed(efx, value, EF4_PAGED_REG(page, reg));
249 }
250 #define ef4_writed_page(efx, value, reg, page)				\
251 	_ef4_writed_page(efx, value,					\
252 			 reg +						\
253 			 BUILD_BUG_ON_ZERO((reg) != 0x400 &&		\
254 					   (reg) != 0x420 &&		\
255 					   (reg) != 0x830 &&		\
256 					   (reg) != 0x83c &&		\
257 					   (reg) != 0xa18 &&		\
258 					   (reg) != 0xa1c),		\
259 			 page)
260 
261 /* Write TIMER_COMMAND.  This is a page-mapped 32-bit CSR, but a bug
262  * in the BIU means that writes to TIMER_COMMAND[0] invalidate the
263  * collector register.
264  */
_ef4_writed_page_locked(struct ef4_nic * efx,const ef4_dword_t * value,unsigned int reg,unsigned int page)265 static inline void _ef4_writed_page_locked(struct ef4_nic *efx,
266 					   const ef4_dword_t *value,
267 					   unsigned int reg,
268 					   unsigned int page)
269 {
270 	unsigned long flags __attribute__ ((unused));
271 
272 	if (page == 0) {
273 		spin_lock_irqsave(&efx->biu_lock, flags);
274 		ef4_writed(efx, value, EF4_PAGED_REG(page, reg));
275 		spin_unlock_irqrestore(&efx->biu_lock, flags);
276 	} else {
277 		ef4_writed(efx, value, EF4_PAGED_REG(page, reg));
278 	}
279 }
280 #define ef4_writed_page_locked(efx, value, reg, page)			\
281 	_ef4_writed_page_locked(efx, value,				\
282 				reg + BUILD_BUG_ON_ZERO((reg) != 0x420), \
283 				page)
284 
285 #endif /* EF4_IO_H */
286