1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * linux/drivers/mmc/host/mmci.h - ARM PrimeCell MMCI PL180/1 driver
4 *
5 * Copyright (C) 2003 Deep Blue Solutions, Ltd, All Rights Reserved.
6 */
7#define MMCIPOWER 0x000
8#define MCI_PWR_OFF 0x00
9#define MCI_PWR_UP 0x02
10#define MCI_PWR_ON 0x03
11#define MCI_OD (1 << 6)
12#define MCI_ROD (1 << 7)
13/*
14 * The ST Micro version does not have ROD and reuse the voltage registers for
15 * direction settings.
16 */
17#define MCI_ST_DATA2DIREN (1 << 2)
18#define MCI_ST_CMDDIREN (1 << 3)
19#define MCI_ST_DATA0DIREN (1 << 4)
20#define MCI_ST_DATA31DIREN (1 << 5)
21#define MCI_ST_FBCLKEN (1 << 7)
22#define MCI_ST_DATA74DIREN (1 << 8)
23/*
24 * The STM32 sdmmc does not have PWR_UP/OD/ROD
25 * and uses the power register for
26 */
27#define MCI_STM32_PWR_CYC 0x02
28#define MCI_STM32_VSWITCH BIT(2)
29#define MCI_STM32_VSWITCHEN BIT(3)
30#define MCI_STM32_DIRPOL BIT(4)
31
32#define MMCICLOCK 0x004
33#define MCI_CLK_ENABLE (1 << 8)
34#define MCI_CLK_PWRSAVE (1 << 9)
35#define MCI_CLK_BYPASS (1 << 10)
36#define MCI_4BIT_BUS (1 << 11)
37/*
38 * 8bit wide buses, hardware flow contronl, negative edges and clock inversion
39 * supported in ST Micro U300 and Ux500 versions
40 */
41#define MCI_ST_8BIT_BUS (1 << 12)
42#define MCI_ST_U300_HWFCEN (1 << 13)
43#define MCI_ST_UX500_NEG_EDGE (1 << 13)
44#define MCI_ST_UX500_HWFCEN (1 << 14)
45#define MCI_ST_UX500_CLK_INV (1 << 15)
46/* Modified PL180 on Versatile Express platform */
47#define MCI_ARM_HWFCEN (1 << 12)
48
49/* Modified on Qualcomm Integrations */
50#define MCI_QCOM_CLK_WIDEBUS_8 (BIT(10) | BIT(11))
51#define MCI_QCOM_CLK_FLOWENA BIT(12)
52#define MCI_QCOM_CLK_INVERTOUT BIT(13)
53
54/* select in latch data and command in */
55#define MCI_QCOM_CLK_SELECT_IN_FBCLK BIT(15)
56#define MCI_QCOM_CLK_SELECT_IN_DDR_MODE (BIT(14) | BIT(15))
57
58/* Modified on STM32 sdmmc */
59#define MCI_STM32_CLK_CLKDIV_MSK GENMASK(9, 0)
60#define MCI_STM32_CLK_WIDEBUS_4 BIT(14)
61#define MCI_STM32_CLK_WIDEBUS_8 BIT(15)
62#define MCI_STM32_CLK_NEGEDGE BIT(16)
63#define MCI_STM32_CLK_HWFCEN BIT(17)
64#define MCI_STM32_CLK_DDR BIT(18)
65#define MCI_STM32_CLK_BUSSPEED BIT(19)
66#define MCI_STM32_CLK_SEL_MSK GENMASK(21, 20)
67#define MCI_STM32_CLK_SELCK (0 << 20)
68#define MCI_STM32_CLK_SELCKIN (1 << 20)
69#define MCI_STM32_CLK_SELFBCK (2 << 20)
70
71#define MMCIARGUMENT 0x008
72
73/* The command register controls the Command Path State Machine (CPSM) */
74#define MMCICOMMAND 0x00c
75#define MCI_CPSM_RESPONSE BIT(6)
76#define MCI_CPSM_LONGRSP BIT(7)
77#define MCI_CPSM_INTERRUPT BIT(8)
78#define MCI_CPSM_PENDING BIT(9)
79#define MCI_CPSM_ENABLE BIT(10)
80/* Command register flag extenstions in the ST Micro versions */
81#define MCI_CPSM_ST_SDIO_SUSP BIT(11)
82#define MCI_CPSM_ST_ENCMD_COMPL BIT(12)
83#define MCI_CPSM_ST_NIEN BIT(13)
84#define MCI_CPSM_ST_CE_ATACMD BIT(14)
85/* Command register flag extensions in the Qualcomm versions */
86#define MCI_CPSM_QCOM_PROGENA BIT(11)
87#define MCI_CPSM_QCOM_DATCMD BIT(12)
88#define MCI_CPSM_QCOM_MCIABORT BIT(13)
89#define MCI_CPSM_QCOM_CCSENABLE BIT(14)
90#define MCI_CPSM_QCOM_CCSDISABLE BIT(15)
91#define MCI_CPSM_QCOM_AUTO_CMD19 BIT(16)
92#define MCI_CPSM_QCOM_AUTO_CMD21 BIT(21)
93/* Command register in STM32 sdmmc versions */
94#define MCI_CPSM_STM32_CMDTRANS BIT(6)
95#define MCI_CPSM_STM32_CMDSTOP BIT(7)
96#define MCI_CPSM_STM32_WAITRESP_MASK GENMASK(9, 8)
97#define MCI_CPSM_STM32_NORSP (0 << 8)
98#define MCI_CPSM_STM32_SRSP_CRC (1 << 8)
99#define MCI_CPSM_STM32_SRSP (2 << 8)
100#define MCI_CPSM_STM32_LRSP_CRC (3 << 8)
101#define MCI_CPSM_STM32_ENABLE BIT(12)
102
103#define MMCIRESPCMD 0x010
104#define MMCIRESPONSE0 0x014
105#define MMCIRESPONSE1 0x018
106#define MMCIRESPONSE2 0x01c
107#define MMCIRESPONSE3 0x020
108#define MMCIDATATIMER 0x024
109#define MMCIDATALENGTH 0x028
110
111/* The data control register controls the Data Path State Machine (DPSM) */
112#define MMCIDATACTRL 0x02c
113#define MCI_DPSM_ENABLE BIT(0)
114#define MCI_DPSM_DIRECTION BIT(1)
115#define MCI_DPSM_MODE BIT(2)
116#define MCI_DPSM_DMAENABLE BIT(3)
117#define MCI_DPSM_BLOCKSIZE BIT(4)
118/* Control register extensions in the ST Micro U300 and Ux500 versions */
119#define MCI_DPSM_ST_RWSTART BIT(8)
120#define MCI_DPSM_ST_RWSTOP BIT(9)
121#define MCI_DPSM_ST_RWMOD BIT(10)
122#define MCI_DPSM_ST_SDIOEN BIT(11)
123/* Control register extensions in the ST Micro Ux500 versions */
124#define MCI_DPSM_ST_DMAREQCTL BIT(12)
125#define MCI_DPSM_ST_DBOOTMODEEN BIT(13)
126#define MCI_DPSM_ST_BUSYMODE BIT(14)
127#define MCI_DPSM_ST_DDRMODE BIT(15)
128/* Control register extensions in the Qualcomm versions */
129#define MCI_DPSM_QCOM_DATA_PEND BIT(17)
130#define MCI_DPSM_QCOM_RX_DATA_PEND BIT(20)
131/* Control register extensions in STM32 versions */
132#define MCI_DPSM_STM32_MODE_BLOCK (0 << 2)
133#define MCI_DPSM_STM32_MODE_SDIO (1 << 2)
134#define MCI_DPSM_STM32_MODE_STREAM (2 << 2)
135#define MCI_DPSM_STM32_MODE_BLOCK_STOP (3 << 2)
136
137#define MMCIDATACNT 0x030
138#define MMCISTATUS 0x034
139#define MCI_CMDCRCFAIL (1 << 0)
140#define MCI_DATACRCFAIL (1 << 1)
141#define MCI_CMDTIMEOUT (1 << 2)
142#define MCI_DATATIMEOUT (1 << 3)
143#define MCI_TXUNDERRUN (1 << 4)
144#define MCI_RXOVERRUN (1 << 5)
145#define MCI_CMDRESPEND (1 << 6)
146#define MCI_CMDSENT (1 << 7)
147#define MCI_DATAEND (1 << 8)
148#define MCI_STARTBITERR (1 << 9)
149#define MCI_DATABLOCKEND (1 << 10)
150#define MCI_CMDACTIVE (1 << 11)
151#define MCI_TXACTIVE (1 << 12)
152#define MCI_RXACTIVE (1 << 13)
153#define MCI_TXFIFOHALFEMPTY (1 << 14)
154#define MCI_RXFIFOHALFFULL (1 << 15)
155#define MCI_TXFIFOFULL (1 << 16)
156#define MCI_RXFIFOFULL (1 << 17)
157#define MCI_TXFIFOEMPTY (1 << 18)
158#define MCI_RXFIFOEMPTY (1 << 19)
159#define MCI_TXDATAAVLBL (1 << 20)
160#define MCI_RXDATAAVLBL (1 << 21)
161/* Extended status bits for the ST Micro variants */
162#define MCI_ST_SDIOIT (1 << 22)
163#define MCI_ST_CEATAEND (1 << 23)
164#define MCI_ST_CARDBUSY (1 << 24)
165/* Extended status bits for the STM32 variants */
166#define MCI_STM32_BUSYD0 BIT(20)
167#define MCI_STM32_BUSYD0END BIT(21)
168#define MCI_STM32_VSWEND BIT(25)
169
170#define MMCICLEAR 0x038
171#define MCI_CMDCRCFAILCLR (1 << 0)
172#define MCI_DATACRCFAILCLR (1 << 1)
173#define MCI_CMDTIMEOUTCLR (1 << 2)
174#define MCI_DATATIMEOUTCLR (1 << 3)
175#define MCI_TXUNDERRUNCLR (1 << 4)
176#define MCI_RXOVERRUNCLR (1 << 5)
177#define MCI_CMDRESPENDCLR (1 << 6)
178#define MCI_CMDSENTCLR (1 << 7)
179#define MCI_DATAENDCLR (1 << 8)
180#define MCI_STARTBITERRCLR (1 << 9)
181#define MCI_DATABLOCKENDCLR (1 << 10)
182/* Extended status bits for the ST Micro variants */
183#define MCI_ST_SDIOITC (1 << 22)
184#define MCI_ST_CEATAENDC (1 << 23)
185#define MCI_ST_BUSYENDC (1 << 24)
186/* Extended clear bits for the STM32 variants */
187#define MCI_STM32_VSWENDC BIT(25)
188#define MCI_STM32_CKSTOPC BIT(26)
189
190#define MMCIMASK0 0x03c
191#define MCI_CMDCRCFAILMASK (1 << 0)
192#define MCI_DATACRCFAILMASK (1 << 1)
193#define MCI_CMDTIMEOUTMASK (1 << 2)
194#define MCI_DATATIMEOUTMASK (1 << 3)
195#define MCI_TXUNDERRUNMASK (1 << 4)
196#define MCI_RXOVERRUNMASK (1 << 5)
197#define MCI_CMDRESPENDMASK (1 << 6)
198#define MCI_CMDSENTMASK (1 << 7)
199#define MCI_DATAENDMASK (1 << 8)
200#define MCI_STARTBITERRMASK (1 << 9)
201#define MCI_DATABLOCKENDMASK (1 << 10)
202#define MCI_CMDACTIVEMASK (1 << 11)
203#define MCI_TXACTIVEMASK (1 << 12)
204#define MCI_RXACTIVEMASK (1 << 13)
205#define MCI_TXFIFOHALFEMPTYMASK (1 << 14)
206#define MCI_RXFIFOHALFFULLMASK (1 << 15)
207#define MCI_TXFIFOFULLMASK (1 << 16)
208#define MCI_RXFIFOFULLMASK (1 << 17)
209#define MCI_TXFIFOEMPTYMASK (1 << 18)
210#define MCI_RXFIFOEMPTYMASK (1 << 19)
211#define MCI_TXDATAAVLBLMASK (1 << 20)
212#define MCI_RXDATAAVLBLMASK (1 << 21)
213/* Extended status bits for the ST Micro variants */
214#define MCI_ST_SDIOITMASK (1 << 22)
215#define MCI_ST_CEATAENDMASK (1 << 23)
216#define MCI_ST_BUSYENDMASK (1 << 24)
217/* Extended status bits for the STM32 variants */
218#define MCI_STM32_BUSYD0ENDMASK BIT(21)
219
220#define MMCIMASK1 0x040
221
222/* STM32 sdmmc data FIFO threshold register */
223#define MMCI_STM32_FIFOTHRR 0x044
224#define MMCI_STM32_THR_MASK GENMASK(3, 0)
225
226#define MMCIFIFOCNT 0x048
227#define MMCIFIFO 0x080 /* to 0x0bc */
228
229/* STM32 sdmmc registers for IDMA (Internal DMA) */
230#define MMCI_STM32_IDMACTRLR 0x050
231#define MMCI_STM32_IDMAEN BIT(0)
232#define MMCI_STM32_IDMALLIEN BIT(1)
233
234#define MMCI_STM32_IDMABSIZER 0x054
235
236#define MMCI_STM32_IDMABASE0R 0x058
237
238#define MMCI_STM32_IDMALAR 0x64
239#define MMCI_STM32_IDMALA_MASK GENMASK(13, 0)
240#define MMCI_STM32_ABR BIT(29)
241#define MMCI_STM32_ULS BIT(30)
242#define MMCI_STM32_ULA BIT(31)
243
244#define MMCI_STM32_IDMABAR 0x68
245
246#define MCI_IRQENABLE \
247 (MCI_CMDCRCFAILMASK | MCI_DATACRCFAILMASK | MCI_CMDTIMEOUTMASK | \
248 MCI_DATATIMEOUTMASK | MCI_TXUNDERRUNMASK | MCI_RXOVERRUNMASK | \
249 MCI_CMDRESPENDMASK | MCI_CMDSENTMASK)
250
251/* These interrupts are directed to IRQ1 when two IRQ lines are available */
252#define MCI_IRQ_PIO_MASK \
253 (MCI_RXFIFOHALFFULLMASK | MCI_RXDATAAVLBLMASK | \
254 MCI_TXFIFOHALFEMPTYMASK)
255
256#define MCI_IRQ_PIO_STM32_MASK \
257 (MCI_RXFIFOHALFFULLMASK | MCI_TXFIFOHALFEMPTYMASK)
258
259#define NR_SG 128
260
261#define MMCI_PINCTRL_STATE_OPENDRAIN "opendrain"
262
263struct clk;
264struct dma_chan;
265struct mmci_host;
266
267/**
268 * enum mmci_busy_state - enumerate the busy detect wait states
269 *
270 * This is used for the state machine waiting for different busy detect
271 * interrupts on hardware that fire a single IRQ for start and end of
272 * the busy detect phase on DAT0.
273 */
274enum mmci_busy_state {
275 MMCI_BUSY_WAITING_FOR_START_IRQ,
276 MMCI_BUSY_WAITING_FOR_END_IRQ,
277 MMCI_BUSY_DONE,
278};
279
280/**
281 * struct variant_data - MMCI variant-specific quirks
282 * @clkreg: default value for MCICLOCK register
283 * @clkreg_enable: enable value for MMCICLOCK register
284 * @clkreg_8bit_bus_enable: enable value for 8 bit bus
285 * @clkreg_neg_edge_enable: enable value for inverted data/cmd output
286 * @cmdreg_cpsm_enable: enable value for CPSM
287 * @cmdreg_lrsp_crc: enable value for long response with crc
288 * @cmdreg_srsp_crc: enable value for short response with crc
289 * @cmdreg_srsp: enable value for short response without crc
290 * @cmdreg_stop: enable value for stop and abort transmission
291 * @datalength_bits: number of bits in the MMCIDATALENGTH register
292 * @fifosize: number of bytes that can be written when MMCI_TXFIFOEMPTY
293 * is asserted (likewise for RX)
294 * @fifohalfsize: number of bytes that can be written when MCI_TXFIFOHALFEMPTY
295 * is asserted (likewise for RX)
296 * @data_cmd_enable: enable value for data commands.
297 * @st_sdio: enable ST specific SDIO logic
298 * @st_clkdiv: true if using a ST-specific clock divider algorithm
299 * @stm32_clkdiv: true if using a STM32-specific clock divider algorithm
300 * @datactrl_mask_ddrmode: ddr mode mask in datactrl register.
301 * @datactrl_mask_sdio: SDIO enable mask in datactrl register
302 * @datactrl_blocksz: block size in power of two
303 * @datactrl_any_blocksz: true if block any block sizes are accepted by
304 * hardware, such as with some SDIO traffic that send
305 * odd packets.
306 * @dma_power_of_2: DMA only works with blocks that are a power of 2.
307 * @datactrl_first: true if data must be setup before send command
308 * @datacnt_useless: true if you could not use datacnt register to read
309 * remaining data
310 * @pwrreg_powerup: power up value for MMCIPOWER register
311 * @f_max: maximum clk frequency supported by the controller.
312 * @signal_direction: input/out direction of bus signals can be indicated
313 * @pwrreg_clkgate: MMCIPOWER register must be used to gate the clock
314 * @busy_detect: true if the variant supports busy detection on DAT0.
315 * @busy_timeout: true if the variant starts data timer when the DPSM
316 * enter in Wait_R or Busy state.
317 * @busy_dpsm_flag: bitmask enabling busy detection in the DPSM
318 * @busy_detect_flag: bitmask identifying the bit in the MMCISTATUS register
319 * indicating that the card is busy
320 * @busy_detect_mask: bitmask identifying the bit in the MMCIMASK0 to mask for
321 * getting busy end detection interrupts
322 * @pwrreg_nopower: bits in MMCIPOWER don't controls ext. power supply
323 * @explicit_mclk_control: enable explicit mclk control in driver.
324 * @qcom_fifo: enables qcom specific fifo pio read logic.
325 * @qcom_dml: enables qcom specific dma glue for dma transfers.
326 * @reversed_irq_handling: handle data irq before cmd irq.
327 * @mmcimask1: true if variant have a MMCIMASK1 register.
328 * @irq_pio_mask: bitmask used to manage interrupt pio transfert in mmcimask
329 * register
330 * @start_err: bitmask identifying the STARTBITERR bit inside MMCISTATUS
331 * register.
332 * @opendrain: bitmask identifying the OPENDRAIN bit inside MMCIPOWER register
333 * @dma_lli: true if variant has dma link list feature.
334 * @stm32_idmabsize_mask: stm32 sdmmc idma buffer size.
335 * @dma_flow_controller: use peripheral as flow controller for DMA.
336 */
337struct variant_data {
338 unsigned int clkreg;
339 unsigned int clkreg_enable;
340 unsigned int clkreg_8bit_bus_enable;
341 unsigned int clkreg_neg_edge_enable;
342 unsigned int cmdreg_cpsm_enable;
343 unsigned int cmdreg_lrsp_crc;
344 unsigned int cmdreg_srsp_crc;
345 unsigned int cmdreg_srsp;
346 unsigned int cmdreg_stop;
347 unsigned int datalength_bits;
348 unsigned int fifosize;
349 unsigned int fifohalfsize;
350 unsigned int data_cmd_enable;
351 unsigned int datactrl_mask_ddrmode;
352 unsigned int datactrl_mask_sdio;
353 unsigned int datactrl_blocksz;
354 u8 datactrl_any_blocksz:1;
355 u8 dma_power_of_2:1;
356 u8 datactrl_first:1;
357 u8 datacnt_useless:1;
358 u8 st_sdio:1;
359 u8 st_clkdiv:1;
360 u8 stm32_clkdiv:1;
361 u32 pwrreg_powerup;
362 u32 f_max;
363 u8 signal_direction:1;
364 u8 pwrreg_clkgate:1;
365 u8 busy_detect:1;
366 u8 busy_timeout:1;
367 u32 busy_dpsm_flag;
368 u32 busy_detect_flag;
369 u32 busy_detect_mask;
370 u8 pwrreg_nopower:1;
371 u8 explicit_mclk_control:1;
372 u8 qcom_fifo:1;
373 u8 qcom_dml:1;
374 u8 reversed_irq_handling:1;
375 u8 mmcimask1:1;
376 unsigned int irq_pio_mask;
377 u32 start_err;
378 u32 opendrain;
379 u8 dma_lli:1;
380 u32 stm32_idmabsize_mask;
381 u32 stm32_idmabsize_align;
382 bool dma_flow_controller;
383 void (*init)(struct mmci_host *host);
384};
385
386/* mmci variant callbacks */
387struct mmci_host_ops {
388 int (*validate_data)(struct mmci_host *host, struct mmc_data *data);
389 int (*prep_data)(struct mmci_host *host, struct mmc_data *data,
390 bool next);
391 void (*unprep_data)(struct mmci_host *host, struct mmc_data *data,
392 int err);
393 u32 (*get_datactrl_cfg)(struct mmci_host *host);
394 void (*get_next_data)(struct mmci_host *host, struct mmc_data *data);
395 int (*dma_setup)(struct mmci_host *host);
396 void (*dma_release)(struct mmci_host *host);
397 int (*dma_start)(struct mmci_host *host, unsigned int *datactrl);
398 void (*dma_finalize)(struct mmci_host *host, struct mmc_data *data);
399 void (*dma_error)(struct mmci_host *host);
400 void (*set_clkreg)(struct mmci_host *host, unsigned int desired);
401 void (*set_pwrreg)(struct mmci_host *host, unsigned int pwr);
402 bool (*busy_complete)(struct mmci_host *host, struct mmc_command *cmd, u32 status, u32 err_msk);
403 void (*pre_sig_volt_switch)(struct mmci_host *host);
404 int (*post_sig_volt_switch)(struct mmci_host *host, struct mmc_ios *ios);
405};
406
407struct mmci_host {
408 phys_addr_t phybase;
409 void __iomem *base;
410 struct mmc_request *mrq;
411 struct mmc_command *cmd;
412 struct mmc_command stop_abort;
413 struct mmc_data *data;
414 struct mmc_host *mmc;
415 struct clk *clk;
416 u8 singleirq:1;
417
418 struct reset_control *rst;
419
420 spinlock_t lock;
421
422 unsigned int mclk;
423 /* cached value of requested clk in set_ios */
424 unsigned int clock_cache;
425 unsigned int cclk;
426 u32 pwr_reg;
427 u32 pwr_reg_add;
428 u32 clk_reg;
429 u32 clk_reg_add;
430 u32 datactrl_reg;
431 enum mmci_busy_state busy_state;
432 u32 busy_status;
433 u32 mask1_reg;
434 u8 vqmmc_enabled:1;
435 struct mmci_platform_data *plat;
436 struct mmc_host_ops *mmc_ops;
437 struct mmci_host_ops *ops;
438 struct variant_data *variant;
439 void *variant_priv;
440 struct pinctrl *pinctrl;
441 struct pinctrl_state *pins_opendrain;
442
443 u8 hw_designer;
444 u8 hw_revision:4;
445
446 struct timer_list timer;
447 unsigned int oldstat;
448 u32 irq_action;
449
450 /* pio stuff */
451 struct sg_mapping_iter sg_miter;
452 unsigned int size;
453 int (*get_rx_fifocnt)(struct mmci_host *h, u32 status, int remain);
454
455 u8 use_dma:1;
456 u8 dma_in_progress:1;
457 void *dma_priv;
458
459 s32 next_cookie;
460 struct delayed_work ux500_busy_timeout_work;
461};
462
463#define dma_inprogress(host) ((host)->dma_in_progress)
464
465void mmci_write_clkreg(struct mmci_host *host, u32 clk);
466void mmci_write_pwrreg(struct mmci_host *host, u32 pwr);
467
468static inline u32 mmci_dctrl_blksz(struct mmci_host *host)
469{
470 return (ffs(host->data->blksz) - 1) << 4;
471}
472
473#ifdef CONFIG_DMA_ENGINE
474int mmci_dmae_prep_data(struct mmci_host *host, struct mmc_data *data,
475 bool next);
476void mmci_dmae_unprep_data(struct mmci_host *host, struct mmc_data *data,
477 int err);
478void mmci_dmae_get_next_data(struct mmci_host *host, struct mmc_data *data);
479int mmci_dmae_setup(struct mmci_host *host);
480void mmci_dmae_release(struct mmci_host *host);
481int mmci_dmae_start(struct mmci_host *host, unsigned int *datactrl);
482void mmci_dmae_finalize(struct mmci_host *host, struct mmc_data *data);
483void mmci_dmae_error(struct mmci_host *host);
484#endif
485
486#ifdef CONFIG_MMC_QCOM_DML
487void qcom_variant_init(struct mmci_host *host);
488#else
489static inline void qcom_variant_init(struct mmci_host *host) {}
490#endif
491
492#ifdef CONFIG_MMC_STM32_SDMMC
493void sdmmc_variant_init(struct mmci_host *host);
494#else
495static inline void sdmmc_variant_init(struct mmci_host *host) {}
496#endif
497

source code of linux/drivers/mmc/host/mmci.h