xref: /openbmc/linux/drivers/net/ethernet/sfc/nic.c (revision 3a83e4e6)
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 #include <linux/bitops.h>
9 #include <linux/delay.h>
10 #include <linux/interrupt.h>
11 #include <linux/pci.h>
12 #include <linux/module.h>
13 #include <linux/seq_file.h>
14 #include <linux/cpu_rmap.h>
15 #include "net_driver.h"
16 #include "bitfield.h"
17 #include "efx.h"
18 #include "nic.h"
19 #include "ef10_regs.h"
20 #include "farch_regs.h"
21 #include "io.h"
22 #include "workarounds.h"
23 #include "mcdi_pcol.h"
24 
25 /**************************************************************************
26  *
27  * Generic buffer handling
28  * These buffers are used for interrupt status, MAC stats, etc.
29  *
30  **************************************************************************/
31 
32 int efx_nic_alloc_buffer(struct efx_nic *efx, struct efx_buffer *buffer,
33 			 unsigned int len, gfp_t gfp_flags)
34 {
35 	buffer->addr = dma_alloc_coherent(&efx->pci_dev->dev, len,
36 					  &buffer->dma_addr, gfp_flags);
37 	if (!buffer->addr)
38 		return -ENOMEM;
39 	buffer->len = len;
40 	return 0;
41 }
42 
43 void efx_nic_free_buffer(struct efx_nic *efx, struct efx_buffer *buffer)
44 {
45 	if (buffer->addr) {
46 		dma_free_coherent(&efx->pci_dev->dev, buffer->len,
47 				  buffer->addr, buffer->dma_addr);
48 		buffer->addr = NULL;
49 	}
50 }
51 
52 /* Check whether an event is present in the eventq at the current
53  * read pointer.  Only useful for self-test.
54  */
55 bool efx_nic_event_present(struct efx_channel *channel)
56 {
57 	return efx_event_present(efx_event(channel, channel->eventq_read_ptr));
58 }
59 
60 void efx_nic_event_test_start(struct efx_channel *channel)
61 {
62 	channel->event_test_cpu = -1;
63 	smp_wmb();
64 	channel->efx->type->ev_test_generate(channel);
65 }
66 
67 int efx_nic_irq_test_start(struct efx_nic *efx)
68 {
69 	efx->last_irq_cpu = -1;
70 	smp_wmb();
71 	return efx->type->irq_test_generate(efx);
72 }
73 
74 /* Hook interrupt handler(s)
75  * Try MSI and then legacy interrupts.
76  */
77 int efx_nic_init_interrupt(struct efx_nic *efx)
78 {
79 	struct efx_channel *channel;
80 	unsigned int n_irqs;
81 	int rc;
82 
83 	if (!EFX_INT_MODE_USE_MSI(efx)) {
84 		rc = request_irq(efx->legacy_irq,
85 				 efx->type->irq_handle_legacy, IRQF_SHARED,
86 				 efx->name, efx);
87 		if (rc) {
88 			netif_err(efx, drv, efx->net_dev,
89 				  "failed to hook legacy IRQ %d\n",
90 				  efx->pci_dev->irq);
91 			goto fail1;
92 		}
93 		return 0;
94 	}
95 
96 #ifdef CONFIG_RFS_ACCEL
97 	if (efx->interrupt_mode == EFX_INT_MODE_MSIX) {
98 		efx->net_dev->rx_cpu_rmap =
99 			alloc_irq_cpu_rmap(efx->n_rx_channels);
100 		if (!efx->net_dev->rx_cpu_rmap) {
101 			rc = -ENOMEM;
102 			goto fail1;
103 		}
104 	}
105 #endif
106 
107 	/* Hook MSI or MSI-X interrupt */
108 	n_irqs = 0;
109 	efx_for_each_channel(channel, efx) {
110 		rc = request_irq(channel->irq, efx->type->irq_handle_msi,
111 				 IRQF_PROBE_SHARED, /* Not shared */
112 				 efx->msi_context[channel->channel].name,
113 				 &efx->msi_context[channel->channel]);
114 		if (rc) {
115 			netif_err(efx, drv, efx->net_dev,
116 				  "failed to hook IRQ %d\n", channel->irq);
117 			goto fail2;
118 		}
119 		++n_irqs;
120 
121 #ifdef CONFIG_RFS_ACCEL
122 		if (efx->interrupt_mode == EFX_INT_MODE_MSIX &&
123 		    channel->channel < efx->n_rx_channels) {
124 			rc = irq_cpu_rmap_add(efx->net_dev->rx_cpu_rmap,
125 					      channel->irq);
126 			if (rc)
127 				goto fail2;
128 		}
129 #endif
130 	}
131 
132 	efx->irqs_hooked = true;
133 	return 0;
134 
135  fail2:
136 #ifdef CONFIG_RFS_ACCEL
137 	free_irq_cpu_rmap(efx->net_dev->rx_cpu_rmap);
138 	efx->net_dev->rx_cpu_rmap = NULL;
139 #endif
140 	efx_for_each_channel(channel, efx) {
141 		if (n_irqs-- == 0)
142 			break;
143 		free_irq(channel->irq, &efx->msi_context[channel->channel]);
144 	}
145  fail1:
146 	return rc;
147 }
148 
149 void efx_nic_fini_interrupt(struct efx_nic *efx)
150 {
151 	struct efx_channel *channel;
152 
153 #ifdef CONFIG_RFS_ACCEL
154 	free_irq_cpu_rmap(efx->net_dev->rx_cpu_rmap);
155 	efx->net_dev->rx_cpu_rmap = NULL;
156 #endif
157 
158 	if (!efx->irqs_hooked)
159 		return;
160 	if (EFX_INT_MODE_USE_MSI(efx)) {
161 		/* Disable MSI/MSI-X interrupts */
162 		efx_for_each_channel(channel, efx)
163 			free_irq(channel->irq,
164 				 &efx->msi_context[channel->channel]);
165 	} else {
166 		/* Disable legacy interrupt */
167 		free_irq(efx->legacy_irq, efx);
168 	}
169 	efx->irqs_hooked = false;
170 }
171 
172 /* Register dump */
173 
174 #define REGISTER_REVISION_FA	1
175 #define REGISTER_REVISION_FB	2
176 #define REGISTER_REVISION_FC	3
177 #define REGISTER_REVISION_FZ	3	/* last Falcon arch revision */
178 #define REGISTER_REVISION_ED	4
179 #define REGISTER_REVISION_EZ	4	/* latest EF10 revision */
180 
181 struct efx_nic_reg {
182 	u32 offset:24;
183 	u32 min_revision:3, max_revision:3;
184 };
185 
186 #define REGISTER(name, arch, min_rev, max_rev) {			\
187 	arch ## R_ ## min_rev ## max_rev ## _ ## name,			\
188 	REGISTER_REVISION_ ## arch ## min_rev,				\
189 	REGISTER_REVISION_ ## arch ## max_rev				\
190 }
191 #define REGISTER_AA(name) REGISTER(name, F, A, A)
192 #define REGISTER_AB(name) REGISTER(name, F, A, B)
193 #define REGISTER_AZ(name) REGISTER(name, F, A, Z)
194 #define REGISTER_BB(name) REGISTER(name, F, B, B)
195 #define REGISTER_BZ(name) REGISTER(name, F, B, Z)
196 #define REGISTER_CZ(name) REGISTER(name, F, C, Z)
197 #define REGISTER_DZ(name) REGISTER(name, E, D, Z)
198 
199 static const struct efx_nic_reg efx_nic_regs[] = {
200 	REGISTER_AZ(ADR_REGION),
201 	REGISTER_AZ(INT_EN_KER),
202 	REGISTER_BZ(INT_EN_CHAR),
203 	REGISTER_AZ(INT_ADR_KER),
204 	REGISTER_BZ(INT_ADR_CHAR),
205 	/* INT_ACK_KER is WO */
206 	/* INT_ISR0 is RC */
207 	REGISTER_AZ(HW_INIT),
208 	REGISTER_CZ(USR_EV_CFG),
209 	REGISTER_AB(EE_SPI_HCMD),
210 	REGISTER_AB(EE_SPI_HADR),
211 	REGISTER_AB(EE_SPI_HDATA),
212 	REGISTER_AB(EE_BASE_PAGE),
213 	REGISTER_AB(EE_VPD_CFG0),
214 	/* EE_VPD_SW_CNTL and EE_VPD_SW_DATA are not used */
215 	/* PMBX_DBG_IADDR and PBMX_DBG_IDATA are indirect */
216 	/* PCIE_CORE_INDIRECT is indirect */
217 	REGISTER_AB(NIC_STAT),
218 	REGISTER_AB(GPIO_CTL),
219 	REGISTER_AB(GLB_CTL),
220 	/* FATAL_INTR_KER and FATAL_INTR_CHAR are partly RC */
221 	REGISTER_BZ(DP_CTRL),
222 	REGISTER_AZ(MEM_STAT),
223 	REGISTER_AZ(CS_DEBUG),
224 	REGISTER_AZ(ALTERA_BUILD),
225 	REGISTER_AZ(CSR_SPARE),
226 	REGISTER_AB(PCIE_SD_CTL0123),
227 	REGISTER_AB(PCIE_SD_CTL45),
228 	REGISTER_AB(PCIE_PCS_CTL_STAT),
229 	/* DEBUG_DATA_OUT is not used */
230 	/* DRV_EV is WO */
231 	REGISTER_AZ(EVQ_CTL),
232 	REGISTER_AZ(EVQ_CNT1),
233 	REGISTER_AZ(EVQ_CNT2),
234 	REGISTER_AZ(BUF_TBL_CFG),
235 	REGISTER_AZ(SRM_RX_DC_CFG),
236 	REGISTER_AZ(SRM_TX_DC_CFG),
237 	REGISTER_AZ(SRM_CFG),
238 	/* BUF_TBL_UPD is WO */
239 	REGISTER_AZ(SRM_UPD_EVQ),
240 	REGISTER_AZ(SRAM_PARITY),
241 	REGISTER_AZ(RX_CFG),
242 	REGISTER_BZ(RX_FILTER_CTL),
243 	/* RX_FLUSH_DESCQ is WO */
244 	REGISTER_AZ(RX_DC_CFG),
245 	REGISTER_AZ(RX_DC_PF_WM),
246 	REGISTER_BZ(RX_RSS_TKEY),
247 	/* RX_NODESC_DROP is RC */
248 	REGISTER_AA(RX_SELF_RST),
249 	/* RX_DEBUG, RX_PUSH_DROP are not used */
250 	REGISTER_CZ(RX_RSS_IPV6_REG1),
251 	REGISTER_CZ(RX_RSS_IPV6_REG2),
252 	REGISTER_CZ(RX_RSS_IPV6_REG3),
253 	/* TX_FLUSH_DESCQ is WO */
254 	REGISTER_AZ(TX_DC_CFG),
255 	REGISTER_AA(TX_CHKSM_CFG),
256 	REGISTER_AZ(TX_CFG),
257 	/* TX_PUSH_DROP is not used */
258 	REGISTER_AZ(TX_RESERVED),
259 	REGISTER_BZ(TX_PACE),
260 	/* TX_PACE_DROP_QID is RC */
261 	REGISTER_BB(TX_VLAN),
262 	REGISTER_BZ(TX_IPFIL_PORTEN),
263 	REGISTER_AB(MD_TXD),
264 	REGISTER_AB(MD_RXD),
265 	REGISTER_AB(MD_CS),
266 	REGISTER_AB(MD_PHY_ADR),
267 	REGISTER_AB(MD_ID),
268 	/* MD_STAT is RC */
269 	REGISTER_AB(MAC_STAT_DMA),
270 	REGISTER_AB(MAC_CTRL),
271 	REGISTER_BB(GEN_MODE),
272 	REGISTER_AB(MAC_MC_HASH_REG0),
273 	REGISTER_AB(MAC_MC_HASH_REG1),
274 	REGISTER_AB(GM_CFG1),
275 	REGISTER_AB(GM_CFG2),
276 	/* GM_IPG and GM_HD are not used */
277 	REGISTER_AB(GM_MAX_FLEN),
278 	/* GM_TEST is not used */
279 	REGISTER_AB(GM_ADR1),
280 	REGISTER_AB(GM_ADR2),
281 	REGISTER_AB(GMF_CFG0),
282 	REGISTER_AB(GMF_CFG1),
283 	REGISTER_AB(GMF_CFG2),
284 	REGISTER_AB(GMF_CFG3),
285 	REGISTER_AB(GMF_CFG4),
286 	REGISTER_AB(GMF_CFG5),
287 	REGISTER_BB(TX_SRC_MAC_CTL),
288 	REGISTER_AB(XM_ADR_LO),
289 	REGISTER_AB(XM_ADR_HI),
290 	REGISTER_AB(XM_GLB_CFG),
291 	REGISTER_AB(XM_TX_CFG),
292 	REGISTER_AB(XM_RX_CFG),
293 	REGISTER_AB(XM_MGT_INT_MASK),
294 	REGISTER_AB(XM_FC),
295 	REGISTER_AB(XM_PAUSE_TIME),
296 	REGISTER_AB(XM_TX_PARAM),
297 	REGISTER_AB(XM_RX_PARAM),
298 	/* XM_MGT_INT_MSK (note no 'A') is RC */
299 	REGISTER_AB(XX_PWR_RST),
300 	REGISTER_AB(XX_SD_CTL),
301 	REGISTER_AB(XX_TXDRV_CTL),
302 	/* XX_PRBS_CTL, XX_PRBS_CHK and XX_PRBS_ERR are not used */
303 	/* XX_CORE_STAT is partly RC */
304 	REGISTER_DZ(BIU_HW_REV_ID),
305 	REGISTER_DZ(MC_DB_LWRD),
306 	REGISTER_DZ(MC_DB_HWRD),
307 };
308 
309 struct efx_nic_reg_table {
310 	u32 offset:24;
311 	u32 min_revision:3, max_revision:3;
312 	u32 step:6, rows:21;
313 };
314 
315 #define REGISTER_TABLE_DIMENSIONS(_, offset, arch, min_rev, max_rev, step, rows) { \
316 	offset,								\
317 	REGISTER_REVISION_ ## arch ## min_rev,				\
318 	REGISTER_REVISION_ ## arch ## max_rev,				\
319 	step, rows							\
320 }
321 #define REGISTER_TABLE(name, arch, min_rev, max_rev)			\
322 	REGISTER_TABLE_DIMENSIONS(					\
323 		name, arch ## R_ ## min_rev ## max_rev ## _ ## name,	\
324 		arch, min_rev, max_rev,					\
325 		arch ## R_ ## min_rev ## max_rev ## _ ## name ## _STEP,	\
326 		arch ## R_ ## min_rev ## max_rev ## _ ## name ## _ROWS)
327 #define REGISTER_TABLE_AA(name) REGISTER_TABLE(name, F, A, A)
328 #define REGISTER_TABLE_AZ(name) REGISTER_TABLE(name, F, A, Z)
329 #define REGISTER_TABLE_BB(name) REGISTER_TABLE(name, F, B, B)
330 #define REGISTER_TABLE_BZ(name) REGISTER_TABLE(name, F, B, Z)
331 #define REGISTER_TABLE_BB_CZ(name)					\
332 	REGISTER_TABLE_DIMENSIONS(name, FR_BZ_ ## name, F, B, B,	\
333 				  FR_BZ_ ## name ## _STEP,		\
334 				  FR_BB_ ## name ## _ROWS),		\
335 	REGISTER_TABLE_DIMENSIONS(name, FR_BZ_ ## name, F, C, Z,	\
336 				  FR_BZ_ ## name ## _STEP,		\
337 				  FR_CZ_ ## name ## _ROWS)
338 #define REGISTER_TABLE_CZ(name) REGISTER_TABLE(name, F, C, Z)
339 #define REGISTER_TABLE_DZ(name) REGISTER_TABLE(name, E, D, Z)
340 
341 static const struct efx_nic_reg_table efx_nic_reg_tables[] = {
342 	/* DRIVER is not used */
343 	/* EVQ_RPTR, TIMER_COMMAND, USR_EV and {RX,TX}_DESC_UPD are WO */
344 	REGISTER_TABLE_BB(TX_IPFIL_TBL),
345 	REGISTER_TABLE_BB(TX_SRC_MAC_TBL),
346 	REGISTER_TABLE_AA(RX_DESC_PTR_TBL_KER),
347 	REGISTER_TABLE_BB_CZ(RX_DESC_PTR_TBL),
348 	REGISTER_TABLE_AA(TX_DESC_PTR_TBL_KER),
349 	REGISTER_TABLE_BB_CZ(TX_DESC_PTR_TBL),
350 	REGISTER_TABLE_AA(EVQ_PTR_TBL_KER),
351 	REGISTER_TABLE_BB_CZ(EVQ_PTR_TBL),
352 	/* We can't reasonably read all of the buffer table (up to 8MB!).
353 	 * However this driver will only use a few entries.  Reading
354 	 * 1K entries allows for some expansion of queue count and
355 	 * size before we need to change the version. */
356 	REGISTER_TABLE_DIMENSIONS(BUF_FULL_TBL_KER, FR_AA_BUF_FULL_TBL_KER,
357 				  F, A, A, 8, 1024),
358 	REGISTER_TABLE_DIMENSIONS(BUF_FULL_TBL, FR_BZ_BUF_FULL_TBL,
359 				  F, B, Z, 8, 1024),
360 	REGISTER_TABLE_CZ(RX_MAC_FILTER_TBL0),
361 	REGISTER_TABLE_BB_CZ(TIMER_TBL),
362 	REGISTER_TABLE_BB_CZ(TX_PACE_TBL),
363 	REGISTER_TABLE_BZ(RX_INDIRECTION_TBL),
364 	/* TX_FILTER_TBL0 is huge and not used by this driver */
365 	REGISTER_TABLE_CZ(TX_MAC_FILTER_TBL0),
366 	REGISTER_TABLE_CZ(MC_TREG_SMEM),
367 	/* MSIX_PBA_TABLE is not mapped */
368 	/* SRM_DBG is not mapped (and is redundant with BUF_FLL_TBL) */
369 	REGISTER_TABLE_BZ(RX_FILTER_TBL0),
370 	REGISTER_TABLE_DZ(BIU_MC_SFT_STATUS),
371 };
372 
373 size_t efx_nic_get_regs_len(struct efx_nic *efx)
374 {
375 	const struct efx_nic_reg *reg;
376 	const struct efx_nic_reg_table *table;
377 	size_t len = 0;
378 
379 	for (reg = efx_nic_regs;
380 	     reg < efx_nic_regs + ARRAY_SIZE(efx_nic_regs);
381 	     reg++)
382 		if (efx->type->revision >= reg->min_revision &&
383 		    efx->type->revision <= reg->max_revision)
384 			len += sizeof(efx_oword_t);
385 
386 	for (table = efx_nic_reg_tables;
387 	     table < efx_nic_reg_tables + ARRAY_SIZE(efx_nic_reg_tables);
388 	     table++)
389 		if (efx->type->revision >= table->min_revision &&
390 		    efx->type->revision <= table->max_revision)
391 			len += table->rows * min_t(size_t, table->step, 16);
392 
393 	return len;
394 }
395 
396 void efx_nic_get_regs(struct efx_nic *efx, void *buf)
397 {
398 	const struct efx_nic_reg *reg;
399 	const struct efx_nic_reg_table *table;
400 
401 	for (reg = efx_nic_regs;
402 	     reg < efx_nic_regs + ARRAY_SIZE(efx_nic_regs);
403 	     reg++) {
404 		if (efx->type->revision >= reg->min_revision &&
405 		    efx->type->revision <= reg->max_revision) {
406 			efx_reado(efx, (efx_oword_t *)buf, reg->offset);
407 			buf += sizeof(efx_oword_t);
408 		}
409 	}
410 
411 	for (table = efx_nic_reg_tables;
412 	     table < efx_nic_reg_tables + ARRAY_SIZE(efx_nic_reg_tables);
413 	     table++) {
414 		size_t size, i;
415 
416 		if (!(efx->type->revision >= table->min_revision &&
417 		      efx->type->revision <= table->max_revision))
418 			continue;
419 
420 		size = min_t(size_t, table->step, 16);
421 
422 		for (i = 0; i < table->rows; i++) {
423 			switch (table->step) {
424 			case 4: /* 32-bit SRAM */
425 				efx_readd(efx, buf, table->offset + 4 * i);
426 				break;
427 			case 8: /* 64-bit SRAM */
428 				efx_sram_readq(efx,
429 					       efx->membase + table->offset,
430 					       buf, i);
431 				break;
432 			case 16: /* 128-bit-readable register */
433 				efx_reado_table(efx, buf, table->offset, i);
434 				break;
435 			case 32: /* 128-bit register, interleaved */
436 				efx_reado_table(efx, buf, table->offset, 2 * i);
437 				break;
438 			default:
439 				WARN_ON(1);
440 				return;
441 			}
442 			buf += size;
443 		}
444 	}
445 }
446 
447 /**
448  * efx_nic_describe_stats - Describe supported statistics for ethtool
449  * @desc: Array of &struct efx_hw_stat_desc describing the statistics
450  * @count: Length of the @desc array
451  * @mask: Bitmask of which elements of @desc are enabled
452  * @names: Buffer to copy names to, or %NULL.  The names are copied
453  *	starting at intervals of %ETH_GSTRING_LEN bytes.
454  *
455  * Returns the number of visible statistics, i.e. the number of set
456  * bits in the first @count bits of @mask for which a name is defined.
457  */
458 size_t efx_nic_describe_stats(const struct efx_hw_stat_desc *desc, size_t count,
459 			      const unsigned long *mask, u8 *names)
460 {
461 	size_t visible = 0;
462 	size_t index;
463 
464 	for_each_set_bit(index, mask, count) {
465 		if (desc[index].name) {
466 			if (names) {
467 				strlcpy(names, desc[index].name,
468 					ETH_GSTRING_LEN);
469 				names += ETH_GSTRING_LEN;
470 			}
471 			++visible;
472 		}
473 	}
474 
475 	return visible;
476 }
477 
478 /**
479  * efx_nic_copy_stats - Copy stats from the DMA buffer in to an
480  *	intermediate buffer. This is used to get a consistent
481  *	set of stats while the DMA buffer can be written at any time
482  *	by the NIC.
483  * @efx: The associated NIC.
484  * @dest: Destination buffer. Must be the same size as the DMA buffer.
485  */
486 int efx_nic_copy_stats(struct efx_nic *efx, __le64 *dest)
487 {
488 	__le64 *dma_stats = efx->stats_buffer.addr;
489 	__le64 generation_start, generation_end;
490 	int rc = 0, retry;
491 
492 	if (!dest)
493 		return 0;
494 
495 	if (!dma_stats)
496 		goto return_zeroes;
497 
498 	/* If we're unlucky enough to read statistics during the DMA, wait
499 	 * up to 10ms for it to finish (typically takes <500us)
500 	 */
501 	for (retry = 0; retry < 100; ++retry) {
502 		generation_end = dma_stats[efx->num_mac_stats - 1];
503 		if (generation_end == EFX_MC_STATS_GENERATION_INVALID)
504 			goto return_zeroes;
505 		rmb();
506 		memcpy(dest, dma_stats, efx->num_mac_stats * sizeof(__le64));
507 		rmb();
508 		generation_start = dma_stats[MC_CMD_MAC_GENERATION_START];
509 		if (generation_end == generation_start)
510 			return 0; /* return good data */
511 		udelay(100);
512 	}
513 
514 	rc = -EIO;
515 
516 return_zeroes:
517 	memset(dest, 0, efx->num_mac_stats * sizeof(u64));
518 	return rc;
519 }
520 
521 /**
522  * efx_nic_update_stats - Convert statistics DMA buffer to array of u64
523  * @desc: Array of &struct efx_hw_stat_desc describing the DMA buffer
524  *	layout.  DMA widths of 0, 16, 32 and 64 are supported; where
525  *	the width is specified as 0 the corresponding element of
526  *	@stats is not updated.
527  * @count: Length of the @desc array
528  * @mask: Bitmask of which elements of @desc are enabled
529  * @stats: Buffer to update with the converted statistics.  The length
530  *	of this array must be at least @count.
531  * @dma_buf: DMA buffer containing hardware statistics
532  * @accumulate: If set, the converted values will be added rather than
533  *	directly stored to the corresponding elements of @stats
534  */
535 void efx_nic_update_stats(const struct efx_hw_stat_desc *desc, size_t count,
536 			  const unsigned long *mask,
537 			  u64 *stats, const void *dma_buf, bool accumulate)
538 {
539 	size_t index;
540 
541 	for_each_set_bit(index, mask, count) {
542 		if (desc[index].dma_width) {
543 			const void *addr = dma_buf + desc[index].offset;
544 			u64 val;
545 
546 			switch (desc[index].dma_width) {
547 			case 16:
548 				val = le16_to_cpup((__le16 *)addr);
549 				break;
550 			case 32:
551 				val = le32_to_cpup((__le32 *)addr);
552 				break;
553 			case 64:
554 				val = le64_to_cpup((__le64 *)addr);
555 				break;
556 			default:
557 				WARN_ON(1);
558 				val = 0;
559 				break;
560 			}
561 
562 			if (accumulate)
563 				stats[index] += val;
564 			else
565 				stats[index] = val;
566 		}
567 	}
568 }
569 
570 void efx_nic_fix_nodesc_drop_stat(struct efx_nic *efx, u64 *rx_nodesc_drops)
571 {
572 	/* if down, or this is the first update after coming up */
573 	if (!(efx->net_dev->flags & IFF_UP) || !efx->rx_nodesc_drops_prev_state)
574 		efx->rx_nodesc_drops_while_down +=
575 			*rx_nodesc_drops - efx->rx_nodesc_drops_total;
576 	efx->rx_nodesc_drops_total = *rx_nodesc_drops;
577 	efx->rx_nodesc_drops_prev_state = !!(efx->net_dev->flags & IFF_UP);
578 	*rx_nodesc_drops -= efx->rx_nodesc_drops_while_down;
579 }
580