1 /* 2 * Copyright (C) 2003-2015 Broadcom Corporation 3 * All Rights Reserved 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 (GPL v2) 7 * as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 */ 14 #include <linux/acpi.h> 15 #include <linux/clk.h> 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/platform_device.h> 19 #include <linux/spi/spi.h> 20 #include <linux/of.h> 21 #include <linux/interrupt.h> 22 23 /* SPI Configuration Register */ 24 #define XLP_SPI_CONFIG 0x00 25 #define XLP_SPI_CPHA BIT(0) 26 #define XLP_SPI_CPOL BIT(1) 27 #define XLP_SPI_CS_POL BIT(2) 28 #define XLP_SPI_TXMISO_EN BIT(3) 29 #define XLP_SPI_TXMOSI_EN BIT(4) 30 #define XLP_SPI_RXMISO_EN BIT(5) 31 #define XLP_SPI_CS_LSBFE BIT(10) 32 #define XLP_SPI_RXCAP_EN BIT(11) 33 34 /* SPI Frequency Divider Register */ 35 #define XLP_SPI_FDIV 0x04 36 37 /* SPI Command Register */ 38 #define XLP_SPI_CMD 0x08 39 #define XLP_SPI_CMD_IDLE_MASK 0x0 40 #define XLP_SPI_CMD_TX_MASK 0x1 41 #define XLP_SPI_CMD_RX_MASK 0x2 42 #define XLP_SPI_CMD_TXRX_MASK 0x3 43 #define XLP_SPI_CMD_CONT BIT(4) 44 #define XLP_SPI_XFR_BITCNT_SHIFT 16 45 46 /* SPI Status Register */ 47 #define XLP_SPI_STATUS 0x0c 48 #define XLP_SPI_XFR_PENDING BIT(0) 49 #define XLP_SPI_XFR_DONE BIT(1) 50 #define XLP_SPI_TX_INT BIT(2) 51 #define XLP_SPI_RX_INT BIT(3) 52 #define XLP_SPI_TX_UF BIT(4) 53 #define XLP_SPI_RX_OF BIT(5) 54 #define XLP_SPI_STAT_MASK 0x3f 55 56 /* SPI Interrupt Enable Register */ 57 #define XLP_SPI_INTR_EN 0x10 58 #define XLP_SPI_INTR_DONE BIT(0) 59 #define XLP_SPI_INTR_TXTH BIT(1) 60 #define XLP_SPI_INTR_RXTH BIT(2) 61 #define XLP_SPI_INTR_TXUF BIT(3) 62 #define XLP_SPI_INTR_RXOF BIT(4) 63 64 /* SPI FIFO Threshold Register */ 65 #define XLP_SPI_FIFO_THRESH 0x14 66 67 /* SPI FIFO Word Count Register */ 68 #define XLP_SPI_FIFO_WCNT 0x18 69 #define XLP_SPI_RXFIFO_WCNT_MASK 0xf 70 #define XLP_SPI_TXFIFO_WCNT_MASK 0xf0 71 #define XLP_SPI_TXFIFO_WCNT_SHIFT 4 72 73 /* SPI Transmit Data FIFO Register */ 74 #define XLP_SPI_TXDATA_FIFO 0x1c 75 76 /* SPI Receive Data FIFO Register */ 77 #define XLP_SPI_RXDATA_FIFO 0x20 78 79 /* SPI System Control Register */ 80 #define XLP_SPI_SYSCTRL 0x100 81 #define XLP_SPI_SYS_RESET BIT(0) 82 #define XLP_SPI_SYS_CLKDIS BIT(1) 83 #define XLP_SPI_SYS_PMEN BIT(8) 84 85 #define SPI_CS_OFFSET 0x40 86 #define XLP_SPI_TXRXTH 0x80 87 #define XLP_SPI_FIFO_SIZE 8 88 #define XLP_SPI_MAX_CS 4 89 #define XLP_SPI_DEFAULT_FREQ 133333333 90 #define XLP_SPI_FDIV_MIN 4 91 #define XLP_SPI_FDIV_MAX 65535 92 /* 93 * SPI can transfer only 28 bytes properly at a time. So split the 94 * transfer into 28 bytes size. 95 */ 96 #define XLP_SPI_XFER_SIZE 28 97 98 struct xlp_spi_priv { 99 struct device dev; /* device structure */ 100 void __iomem *base; /* spi registers base address */ 101 const u8 *tx_buf; /* tx data buffer */ 102 u8 *rx_buf; /* rx data buffer */ 103 int tx_len; /* tx xfer length */ 104 int rx_len; /* rx xfer length */ 105 int txerrors; /* TXFIFO underflow count */ 106 int rxerrors; /* RXFIFO overflow count */ 107 int cs; /* slave device chip select */ 108 u32 spi_clk; /* spi clock frequency */ 109 bool cmd_cont; /* cs active */ 110 struct completion done; /* completion notification */ 111 }; 112 113 static inline u32 xlp_spi_reg_read(struct xlp_spi_priv *priv, 114 int cs, int regoff) 115 { 116 return readl(priv->base + regoff + cs * SPI_CS_OFFSET); 117 } 118 119 static inline void xlp_spi_reg_write(struct xlp_spi_priv *priv, int cs, 120 int regoff, u32 val) 121 { 122 writel(val, priv->base + regoff + cs * SPI_CS_OFFSET); 123 } 124 125 static inline void xlp_spi_sysctl_write(struct xlp_spi_priv *priv, 126 int regoff, u32 val) 127 { 128 writel(val, priv->base + regoff); 129 } 130 131 /* 132 * Setup global SPI_SYSCTRL register for all SPI channels. 133 */ 134 static void xlp_spi_sysctl_setup(struct xlp_spi_priv *xspi) 135 { 136 int cs; 137 138 for (cs = 0; cs < XLP_SPI_MAX_CS; cs++) 139 xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL, 140 XLP_SPI_SYS_RESET << cs); 141 xlp_spi_sysctl_write(xspi, XLP_SPI_SYSCTRL, XLP_SPI_SYS_PMEN); 142 } 143 144 static int xlp_spi_setup(struct spi_device *spi) 145 { 146 struct xlp_spi_priv *xspi; 147 u32 fdiv, cfg; 148 int cs; 149 150 xspi = spi_master_get_devdata(spi->master); 151 cs = spi->chip_select; 152 /* 153 * The value of fdiv must be between 4 and 65535. 154 */ 155 fdiv = DIV_ROUND_UP(xspi->spi_clk, spi->max_speed_hz); 156 if (fdiv > XLP_SPI_FDIV_MAX) 157 fdiv = XLP_SPI_FDIV_MAX; 158 else if (fdiv < XLP_SPI_FDIV_MIN) 159 fdiv = XLP_SPI_FDIV_MIN; 160 161 xlp_spi_reg_write(xspi, cs, XLP_SPI_FDIV, fdiv); 162 xlp_spi_reg_write(xspi, cs, XLP_SPI_FIFO_THRESH, XLP_SPI_TXRXTH); 163 cfg = xlp_spi_reg_read(xspi, cs, XLP_SPI_CONFIG); 164 if (spi->mode & SPI_CPHA) 165 cfg |= XLP_SPI_CPHA; 166 else 167 cfg &= ~XLP_SPI_CPHA; 168 if (spi->mode & SPI_CPOL) 169 cfg |= XLP_SPI_CPOL; 170 else 171 cfg &= ~XLP_SPI_CPOL; 172 if (!(spi->mode & SPI_CS_HIGH)) 173 cfg |= XLP_SPI_CS_POL; 174 else 175 cfg &= ~XLP_SPI_CS_POL; 176 if (spi->mode & SPI_LSB_FIRST) 177 cfg |= XLP_SPI_CS_LSBFE; 178 else 179 cfg &= ~XLP_SPI_CS_LSBFE; 180 181 cfg |= XLP_SPI_TXMOSI_EN | XLP_SPI_RXMISO_EN; 182 if (fdiv == 4) 183 cfg |= XLP_SPI_RXCAP_EN; 184 xlp_spi_reg_write(xspi, cs, XLP_SPI_CONFIG, cfg); 185 186 return 0; 187 } 188 189 static void xlp_spi_read_rxfifo(struct xlp_spi_priv *xspi) 190 { 191 u32 rx_data, rxfifo_cnt; 192 int i, j, nbytes; 193 194 rxfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT); 195 rxfifo_cnt &= XLP_SPI_RXFIFO_WCNT_MASK; 196 while (rxfifo_cnt) { 197 rx_data = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_RXDATA_FIFO); 198 j = 0; 199 nbytes = min(xspi->rx_len, 4); 200 for (i = nbytes - 1; i >= 0; i--, j++) 201 xspi->rx_buf[i] = (rx_data >> (j * 8)) & 0xff; 202 203 xspi->rx_len -= nbytes; 204 xspi->rx_buf += nbytes; 205 rxfifo_cnt--; 206 } 207 } 208 209 static void xlp_spi_fill_txfifo(struct xlp_spi_priv *xspi) 210 { 211 u32 tx_data, txfifo_cnt; 212 int i, j, nbytes; 213 214 txfifo_cnt = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_FIFO_WCNT); 215 txfifo_cnt &= XLP_SPI_TXFIFO_WCNT_MASK; 216 txfifo_cnt >>= XLP_SPI_TXFIFO_WCNT_SHIFT; 217 while (xspi->tx_len && (txfifo_cnt < XLP_SPI_FIFO_SIZE)) { 218 j = 0; 219 tx_data = 0; 220 nbytes = min(xspi->tx_len, 4); 221 for (i = nbytes - 1; i >= 0; i--, j++) 222 tx_data |= xspi->tx_buf[i] << (j * 8); 223 224 xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_TXDATA_FIFO, tx_data); 225 xspi->tx_len -= nbytes; 226 xspi->tx_buf += nbytes; 227 txfifo_cnt++; 228 } 229 } 230 231 static irqreturn_t xlp_spi_interrupt(int irq, void *dev_id) 232 { 233 struct xlp_spi_priv *xspi = dev_id; 234 u32 stat; 235 236 stat = xlp_spi_reg_read(xspi, xspi->cs, XLP_SPI_STATUS) & 237 XLP_SPI_STAT_MASK; 238 if (!stat) 239 return IRQ_NONE; 240 241 if (stat & XLP_SPI_TX_INT) { 242 if (xspi->tx_len) 243 xlp_spi_fill_txfifo(xspi); 244 if (stat & XLP_SPI_TX_UF) 245 xspi->txerrors++; 246 } 247 248 if (stat & XLP_SPI_RX_INT) { 249 if (xspi->rx_len) 250 xlp_spi_read_rxfifo(xspi); 251 if (stat & XLP_SPI_RX_OF) 252 xspi->rxerrors++; 253 } 254 255 /* write status back to clear interrupts */ 256 xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_STATUS, stat); 257 if (stat & XLP_SPI_XFR_DONE) 258 complete(&xspi->done); 259 260 return IRQ_HANDLED; 261 } 262 263 static void xlp_spi_send_cmd(struct xlp_spi_priv *xspi, int xfer_len, 264 int cmd_cont) 265 { 266 u32 cmd = 0; 267 268 if (xspi->tx_buf) 269 cmd |= XLP_SPI_CMD_TX_MASK; 270 if (xspi->rx_buf) 271 cmd |= XLP_SPI_CMD_RX_MASK; 272 if (cmd_cont) 273 cmd |= XLP_SPI_CMD_CONT; 274 cmd |= ((xfer_len * 8 - 1) << XLP_SPI_XFR_BITCNT_SHIFT); 275 xlp_spi_reg_write(xspi, xspi->cs, XLP_SPI_CMD, cmd); 276 } 277 278 static int xlp_spi_xfer_block(struct xlp_spi_priv *xs, 279 const unsigned char *tx_buf, 280 unsigned char *rx_buf, int xfer_len, int cmd_cont) 281 { 282 int timeout; 283 u32 intr_mask = 0; 284 285 xs->tx_buf = tx_buf; 286 xs->rx_buf = rx_buf; 287 xs->tx_len = (xs->tx_buf == NULL) ? 0 : xfer_len; 288 xs->rx_len = (xs->rx_buf == NULL) ? 0 : xfer_len; 289 xs->txerrors = xs->rxerrors = 0; 290 291 /* fill TXDATA_FIFO, then send the CMD */ 292 if (xs->tx_len) 293 xlp_spi_fill_txfifo(xs); 294 295 xlp_spi_send_cmd(xs, xfer_len, cmd_cont); 296 297 /* 298 * We are getting some spurious tx interrupts, so avoid enabling 299 * tx interrupts when only rx is in process. 300 * Enable all the interrupts in tx case. 301 */ 302 if (xs->tx_len) 303 intr_mask |= XLP_SPI_INTR_TXTH | XLP_SPI_INTR_TXUF | 304 XLP_SPI_INTR_RXTH | XLP_SPI_INTR_RXOF; 305 else 306 intr_mask |= XLP_SPI_INTR_RXTH | XLP_SPI_INTR_RXOF; 307 308 intr_mask |= XLP_SPI_INTR_DONE; 309 xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, intr_mask); 310 311 timeout = wait_for_completion_timeout(&xs->done, 312 msecs_to_jiffies(1000)); 313 /* Disable interrupts */ 314 xlp_spi_reg_write(xs, xs->cs, XLP_SPI_INTR_EN, 0x0); 315 if (!timeout) { 316 dev_err(&xs->dev, "xfer timedout!\n"); 317 goto out; 318 } 319 if (xs->txerrors || xs->rxerrors) 320 dev_err(&xs->dev, "Over/Underflow rx %d tx %d xfer %d!\n", 321 xs->rxerrors, xs->txerrors, xfer_len); 322 323 return xfer_len; 324 out: 325 return -ETIMEDOUT; 326 } 327 328 static int xlp_spi_txrx_bufs(struct xlp_spi_priv *xs, struct spi_transfer *t) 329 { 330 int bytesleft, sz; 331 unsigned char *rx_buf; 332 const unsigned char *tx_buf; 333 334 tx_buf = t->tx_buf; 335 rx_buf = t->rx_buf; 336 bytesleft = t->len; 337 while (bytesleft) { 338 if (bytesleft > XLP_SPI_XFER_SIZE) 339 sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf, 340 XLP_SPI_XFER_SIZE, 1); 341 else 342 sz = xlp_spi_xfer_block(xs, tx_buf, rx_buf, 343 bytesleft, xs->cmd_cont); 344 if (sz < 0) 345 return sz; 346 bytesleft -= sz; 347 if (tx_buf) 348 tx_buf += sz; 349 if (rx_buf) 350 rx_buf += sz; 351 } 352 return bytesleft; 353 } 354 355 static int xlp_spi_transfer_one(struct spi_master *master, 356 struct spi_device *spi, 357 struct spi_transfer *t) 358 { 359 struct xlp_spi_priv *xspi = spi_master_get_devdata(master); 360 int ret = 0; 361 362 xspi->cs = spi->chip_select; 363 xspi->dev = spi->dev; 364 365 if (spi_transfer_is_last(master, t)) 366 xspi->cmd_cont = 0; 367 else 368 xspi->cmd_cont = 1; 369 370 if (xlp_spi_txrx_bufs(xspi, t)) 371 ret = -EIO; 372 373 spi_finalize_current_transfer(master); 374 return ret; 375 } 376 377 static int xlp_spi_probe(struct platform_device *pdev) 378 { 379 struct spi_master *master; 380 struct xlp_spi_priv *xspi; 381 struct resource *res; 382 struct clk *clk; 383 int irq, err; 384 385 xspi = devm_kzalloc(&pdev->dev, sizeof(*xspi), GFP_KERNEL); 386 if (!xspi) 387 return -ENOMEM; 388 389 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 390 xspi->base = devm_ioremap_resource(&pdev->dev, res); 391 if (IS_ERR(xspi->base)) 392 return PTR_ERR(xspi->base); 393 394 irq = platform_get_irq(pdev, 0); 395 if (irq < 0) { 396 dev_err(&pdev->dev, "no IRQ resource found\n"); 397 return -EINVAL; 398 } 399 err = devm_request_irq(&pdev->dev, irq, xlp_spi_interrupt, 0, 400 pdev->name, xspi); 401 if (err) { 402 dev_err(&pdev->dev, "unable to request irq %d\n", irq); 403 return err; 404 } 405 406 clk = devm_clk_get(&pdev->dev, NULL); 407 if (IS_ERR(clk)) { 408 dev_err(&pdev->dev, "could not get spi clock\n"); 409 return PTR_ERR(clk); 410 } 411 412 xspi->spi_clk = clk_get_rate(clk); 413 414 master = spi_alloc_master(&pdev->dev, 0); 415 if (!master) { 416 dev_err(&pdev->dev, "could not alloc master\n"); 417 return -ENOMEM; 418 } 419 420 master->bus_num = 0; 421 master->num_chipselect = XLP_SPI_MAX_CS; 422 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; 423 master->setup = xlp_spi_setup; 424 master->transfer_one = xlp_spi_transfer_one; 425 master->dev.of_node = pdev->dev.of_node; 426 427 init_completion(&xspi->done); 428 spi_master_set_devdata(master, xspi); 429 xlp_spi_sysctl_setup(xspi); 430 431 /* register spi controller */ 432 err = devm_spi_register_master(&pdev->dev, master); 433 if (err) { 434 dev_err(&pdev->dev, "spi register master failed!\n"); 435 spi_master_put(master); 436 return err; 437 } 438 439 return 0; 440 } 441 442 #ifdef CONFIG_ACPI 443 static const struct acpi_device_id xlp_spi_acpi_match[] = { 444 { "BRCM900D", 0 }, 445 { }, 446 }; 447 MODULE_DEVICE_TABLE(acpi, xlp_spi_acpi_match); 448 #endif 449 450 static const struct of_device_id xlp_spi_dt_id[] = { 451 { .compatible = "netlogic,xlp832-spi" }, 452 { }, 453 }; 454 MODULE_DEVICE_TABLE(of, xlp_spi_dt_id); 455 456 static struct platform_driver xlp_spi_driver = { 457 .probe = xlp_spi_probe, 458 .driver = { 459 .name = "xlp-spi", 460 .of_match_table = xlp_spi_dt_id, 461 .acpi_match_table = ACPI_PTR(xlp_spi_acpi_match), 462 }, 463 }; 464 module_platform_driver(xlp_spi_driver); 465 466 MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>"); 467 MODULE_DESCRIPTION("Netlogic XLP SPI controller driver"); 468 MODULE_LICENSE("GPL v2"); 469