1 /* 2 * Freescale i.MX28 SPI driver 3 * 4 * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com> 5 * on behalf of DENX Software Engineering GmbH 6 * 7 * SPDX-License-Identifier: GPL-2.0+ 8 * 9 * NOTE: This driver only supports the SPI-controller chipselects, 10 * GPIO driven chipselects are not supported. 11 */ 12 13 #include <common.h> 14 #include <malloc.h> 15 #include <spi.h> 16 #include <asm/errno.h> 17 #include <asm/io.h> 18 #include <asm/arch/clock.h> 19 #include <asm/arch/imx-regs.h> 20 #include <asm/arch/sys_proto.h> 21 #include <asm/imx-common/dma.h> 22 23 #define MXS_SPI_MAX_TIMEOUT 1000000 24 #define MXS_SPI_PORT_OFFSET 0x2000 25 #define MXS_SSP_CHIPSELECT_MASK 0x00300000 26 #define MXS_SSP_CHIPSELECT_SHIFT 20 27 28 #define MXSSSP_SMALL_TRANSFER 512 29 30 struct mxs_spi_slave { 31 struct spi_slave slave; 32 uint32_t max_khz; 33 uint32_t mode; 34 struct mxs_ssp_regs *regs; 35 }; 36 37 static inline struct mxs_spi_slave *to_mxs_slave(struct spi_slave *slave) 38 { 39 return container_of(slave, struct mxs_spi_slave, slave); 40 } 41 42 void spi_init(void) 43 { 44 } 45 46 int spi_cs_is_valid(unsigned int bus, unsigned int cs) 47 { 48 /* MXS SPI: 4 ports and 3 chip selects maximum */ 49 if (!mxs_ssp_bus_id_valid(bus) || cs > 2) 50 return 0; 51 else 52 return 1; 53 } 54 55 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, 56 unsigned int max_hz, unsigned int mode) 57 { 58 struct mxs_spi_slave *mxs_slave; 59 60 if (!spi_cs_is_valid(bus, cs)) { 61 printf("mxs_spi: invalid bus %d / chip select %d\n", bus, cs); 62 return NULL; 63 } 64 65 mxs_slave = spi_alloc_slave(struct mxs_spi_slave, bus, cs); 66 if (!mxs_slave) 67 return NULL; 68 69 if (mxs_dma_init_channel(MXS_DMA_CHANNEL_AHB_APBH_SSP0 + bus)) 70 goto err_init; 71 72 mxs_slave->max_khz = max_hz / 1000; 73 mxs_slave->mode = mode; 74 mxs_slave->regs = mxs_ssp_regs_by_bus(bus); 75 76 return &mxs_slave->slave; 77 78 err_init: 79 free(mxs_slave); 80 return NULL; 81 } 82 83 void spi_free_slave(struct spi_slave *slave) 84 { 85 struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave); 86 free(mxs_slave); 87 } 88 89 int spi_claim_bus(struct spi_slave *slave) 90 { 91 struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave); 92 struct mxs_ssp_regs *ssp_regs = mxs_slave->regs; 93 uint32_t reg = 0; 94 95 mxs_reset_block(&ssp_regs->hw_ssp_ctrl0_reg); 96 97 writel((slave->cs << MXS_SSP_CHIPSELECT_SHIFT) | 98 SSP_CTRL0_BUS_WIDTH_ONE_BIT, 99 &ssp_regs->hw_ssp_ctrl0); 100 101 reg = SSP_CTRL1_SSP_MODE_SPI | SSP_CTRL1_WORD_LENGTH_EIGHT_BITS; 102 reg |= (mxs_slave->mode & SPI_CPOL) ? SSP_CTRL1_POLARITY : 0; 103 reg |= (mxs_slave->mode & SPI_CPHA) ? SSP_CTRL1_PHASE : 0; 104 writel(reg, &ssp_regs->hw_ssp_ctrl1); 105 106 writel(0, &ssp_regs->hw_ssp_cmd0); 107 108 mxs_set_ssp_busclock(slave->bus, mxs_slave->max_khz); 109 110 return 0; 111 } 112 113 void spi_release_bus(struct spi_slave *slave) 114 { 115 } 116 117 static void mxs_spi_start_xfer(struct mxs_ssp_regs *ssp_regs) 118 { 119 writel(SSP_CTRL0_LOCK_CS, &ssp_regs->hw_ssp_ctrl0_set); 120 writel(SSP_CTRL0_IGNORE_CRC, &ssp_regs->hw_ssp_ctrl0_clr); 121 } 122 123 static void mxs_spi_end_xfer(struct mxs_ssp_regs *ssp_regs) 124 { 125 writel(SSP_CTRL0_LOCK_CS, &ssp_regs->hw_ssp_ctrl0_clr); 126 writel(SSP_CTRL0_IGNORE_CRC, &ssp_regs->hw_ssp_ctrl0_set); 127 } 128 129 static int mxs_spi_xfer_pio(struct mxs_spi_slave *slave, 130 char *data, int length, int write, unsigned long flags) 131 { 132 struct mxs_ssp_regs *ssp_regs = slave->regs; 133 134 if (flags & SPI_XFER_BEGIN) 135 mxs_spi_start_xfer(ssp_regs); 136 137 while (length--) { 138 /* We transfer 1 byte */ 139 #if defined(CONFIG_MX23) 140 writel(SSP_CTRL0_XFER_COUNT_MASK, &ssp_regs->hw_ssp_ctrl0_clr); 141 writel(1, &ssp_regs->hw_ssp_ctrl0_set); 142 #elif defined(CONFIG_MX28) 143 writel(1, &ssp_regs->hw_ssp_xfer_size); 144 #endif 145 146 if ((flags & SPI_XFER_END) && !length) 147 mxs_spi_end_xfer(ssp_regs); 148 149 if (write) 150 writel(SSP_CTRL0_READ, &ssp_regs->hw_ssp_ctrl0_clr); 151 else 152 writel(SSP_CTRL0_READ, &ssp_regs->hw_ssp_ctrl0_set); 153 154 writel(SSP_CTRL0_RUN, &ssp_regs->hw_ssp_ctrl0_set); 155 156 if (mxs_wait_mask_set(&ssp_regs->hw_ssp_ctrl0_reg, 157 SSP_CTRL0_RUN, MXS_SPI_MAX_TIMEOUT)) { 158 printf("MXS SPI: Timeout waiting for start\n"); 159 return -ETIMEDOUT; 160 } 161 162 if (write) 163 writel(*data++, &ssp_regs->hw_ssp_data); 164 165 writel(SSP_CTRL0_DATA_XFER, &ssp_regs->hw_ssp_ctrl0_set); 166 167 if (!write) { 168 if (mxs_wait_mask_clr(&ssp_regs->hw_ssp_status_reg, 169 SSP_STATUS_FIFO_EMPTY, MXS_SPI_MAX_TIMEOUT)) { 170 printf("MXS SPI: Timeout waiting for data\n"); 171 return -ETIMEDOUT; 172 } 173 174 *data = readl(&ssp_regs->hw_ssp_data); 175 data++; 176 } 177 178 if (mxs_wait_mask_clr(&ssp_regs->hw_ssp_ctrl0_reg, 179 SSP_CTRL0_RUN, MXS_SPI_MAX_TIMEOUT)) { 180 printf("MXS SPI: Timeout waiting for finish\n"); 181 return -ETIMEDOUT; 182 } 183 } 184 185 return 0; 186 } 187 188 static int mxs_spi_xfer_dma(struct mxs_spi_slave *slave, 189 char *data, int length, int write, unsigned long flags) 190 { 191 const int xfer_max_sz = 0xff00; 192 const int desc_count = DIV_ROUND_UP(length, xfer_max_sz) + 1; 193 struct mxs_ssp_regs *ssp_regs = slave->regs; 194 struct mxs_dma_desc *dp; 195 uint32_t ctrl0; 196 uint32_t cache_data_count; 197 const uint32_t dstart = (uint32_t)data; 198 int dmach; 199 int tl; 200 int ret = 0; 201 202 #if defined(CONFIG_MX23) 203 const int mxs_spi_pio_words = 1; 204 #elif defined(CONFIG_MX28) 205 const int mxs_spi_pio_words = 4; 206 #endif 207 208 ALLOC_CACHE_ALIGN_BUFFER(struct mxs_dma_desc, desc, desc_count); 209 210 memset(desc, 0, sizeof(struct mxs_dma_desc) * desc_count); 211 212 ctrl0 = readl(&ssp_regs->hw_ssp_ctrl0); 213 ctrl0 |= SSP_CTRL0_DATA_XFER; 214 215 if (flags & SPI_XFER_BEGIN) 216 ctrl0 |= SSP_CTRL0_LOCK_CS; 217 if (!write) 218 ctrl0 |= SSP_CTRL0_READ; 219 220 if (length % ARCH_DMA_MINALIGN) 221 cache_data_count = roundup(length, ARCH_DMA_MINALIGN); 222 else 223 cache_data_count = length; 224 225 /* Flush data to DRAM so DMA can pick them up */ 226 if (write) 227 flush_dcache_range(dstart, dstart + cache_data_count); 228 229 /* Invalidate the area, so no writeback into the RAM races with DMA */ 230 invalidate_dcache_range(dstart, dstart + cache_data_count); 231 232 dmach = MXS_DMA_CHANNEL_AHB_APBH_SSP0 + slave->slave.bus; 233 234 dp = desc; 235 while (length) { 236 dp->address = (dma_addr_t)dp; 237 dp->cmd.address = (dma_addr_t)data; 238 239 /* 240 * This is correct, even though it does indeed look insane. 241 * I hereby have to, wholeheartedly, thank Freescale Inc., 242 * for always inventing insane hardware and keeping me busy 243 * and employed ;-) 244 */ 245 if (write) 246 dp->cmd.data = MXS_DMA_DESC_COMMAND_DMA_READ; 247 else 248 dp->cmd.data = MXS_DMA_DESC_COMMAND_DMA_WRITE; 249 250 /* 251 * The DMA controller can transfer large chunks (64kB) at 252 * time by setting the transfer length to 0. Setting tl to 253 * 0x10000 will overflow below and make .data contain 0. 254 * Otherwise, 0xff00 is the transfer maximum. 255 */ 256 if (length >= 0x10000) 257 tl = 0x10000; 258 else 259 tl = min(length, xfer_max_sz); 260 261 dp->cmd.data |= 262 ((tl & 0xffff) << MXS_DMA_DESC_BYTES_OFFSET) | 263 (mxs_spi_pio_words << MXS_DMA_DESC_PIO_WORDS_OFFSET) | 264 MXS_DMA_DESC_HALT_ON_TERMINATE | 265 MXS_DMA_DESC_TERMINATE_FLUSH; 266 267 data += tl; 268 length -= tl; 269 270 if (!length) { 271 dp->cmd.data |= MXS_DMA_DESC_IRQ | MXS_DMA_DESC_DEC_SEM; 272 273 if (flags & SPI_XFER_END) { 274 ctrl0 &= ~SSP_CTRL0_LOCK_CS; 275 ctrl0 |= SSP_CTRL0_IGNORE_CRC; 276 } 277 } 278 279 /* 280 * Write CTRL0, CMD0, CMD1 and XFER_SIZE registers in 281 * case of MX28, write only CTRL0 in case of MX23 due 282 * to the difference in register layout. It is utterly 283 * essential that the XFER_SIZE register is written on 284 * a per-descriptor basis with the same size as is the 285 * descriptor! 286 */ 287 dp->cmd.pio_words[0] = ctrl0; 288 #ifdef CONFIG_MX28 289 dp->cmd.pio_words[1] = 0; 290 dp->cmd.pio_words[2] = 0; 291 dp->cmd.pio_words[3] = tl; 292 #endif 293 294 mxs_dma_desc_append(dmach, dp); 295 296 dp++; 297 } 298 299 if (mxs_dma_go(dmach)) 300 ret = -EINVAL; 301 302 /* The data arrived into DRAM, invalidate cache over them */ 303 if (!write) 304 invalidate_dcache_range(dstart, dstart + cache_data_count); 305 306 return ret; 307 } 308 309 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, 310 const void *dout, void *din, unsigned long flags) 311 { 312 struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave); 313 struct mxs_ssp_regs *ssp_regs = mxs_slave->regs; 314 int len = bitlen / 8; 315 char dummy; 316 int write = 0; 317 char *data = NULL; 318 int dma = 1; 319 320 if (bitlen == 0) { 321 if (flags & SPI_XFER_END) { 322 din = (void *)&dummy; 323 len = 1; 324 } else 325 return 0; 326 } 327 328 /* Half-duplex only */ 329 if (din && dout) 330 return -EINVAL; 331 /* No data */ 332 if (!din && !dout) 333 return 0; 334 335 if (dout) { 336 data = (char *)dout; 337 write = 1; 338 } else if (din) { 339 data = (char *)din; 340 write = 0; 341 } 342 343 /* 344 * Check for alignment, if the buffer is aligned, do DMA transfer, 345 * PIO otherwise. This is a temporary workaround until proper bounce 346 * buffer is in place. 347 */ 348 if (dma) { 349 if (((uint32_t)data) & (ARCH_DMA_MINALIGN - 1)) 350 dma = 0; 351 if (((uint32_t)len) & (ARCH_DMA_MINALIGN - 1)) 352 dma = 0; 353 } 354 355 if (!dma || (len < MXSSSP_SMALL_TRANSFER)) { 356 writel(SSP_CTRL1_DMA_ENABLE, &ssp_regs->hw_ssp_ctrl1_clr); 357 return mxs_spi_xfer_pio(mxs_slave, data, len, write, flags); 358 } else { 359 writel(SSP_CTRL1_DMA_ENABLE, &ssp_regs->hw_ssp_ctrl1_set); 360 return mxs_spi_xfer_dma(mxs_slave, data, len, write, flags); 361 } 362 } 363