1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * 8250_lpss.c - Driver for UART on Intel Braswell and various other Intel SoCs 4 * 5 * Copyright (C) 2016 Intel Corporation 6 * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com> 7 */ 8 9 #include <linux/bitops.h> 10 #include <linux/module.h> 11 #include <linux/pci.h> 12 #include <linux/rational.h> 13 14 #include <linux/dmaengine.h> 15 #include <linux/dma/dw.h> 16 17 #include "8250_dwlib.h" 18 19 #define PCI_DEVICE_ID_INTEL_QRK_UARTx 0x0936 20 21 #define PCI_DEVICE_ID_INTEL_BYT_UART1 0x0f0a 22 #define PCI_DEVICE_ID_INTEL_BYT_UART2 0x0f0c 23 24 #define PCI_DEVICE_ID_INTEL_BSW_UART1 0x228a 25 #define PCI_DEVICE_ID_INTEL_BSW_UART2 0x228c 26 27 #define PCI_DEVICE_ID_INTEL_EHL_UART0 0x4b96 28 #define PCI_DEVICE_ID_INTEL_EHL_UART1 0x4b97 29 #define PCI_DEVICE_ID_INTEL_EHL_UART2 0x4b98 30 #define PCI_DEVICE_ID_INTEL_EHL_UART3 0x4b99 31 #define PCI_DEVICE_ID_INTEL_EHL_UART4 0x4b9a 32 #define PCI_DEVICE_ID_INTEL_EHL_UART5 0x4b9b 33 34 #define PCI_DEVICE_ID_INTEL_BDW_UART1 0x9ce3 35 #define PCI_DEVICE_ID_INTEL_BDW_UART2 0x9ce4 36 37 /* Intel LPSS specific registers */ 38 39 #define BYT_PRV_CLK 0x800 40 #define BYT_PRV_CLK_EN BIT(0) 41 #define BYT_PRV_CLK_M_VAL_SHIFT 1 42 #define BYT_PRV_CLK_N_VAL_SHIFT 16 43 #define BYT_PRV_CLK_UPDATE BIT(31) 44 45 #define BYT_TX_OVF_INT 0x820 46 #define BYT_TX_OVF_INT_MASK BIT(1) 47 48 struct lpss8250; 49 50 struct lpss8250_board { 51 unsigned long freq; 52 unsigned int base_baud; 53 int (*setup)(struct lpss8250 *, struct uart_port *p); 54 void (*exit)(struct lpss8250 *); 55 }; 56 57 struct lpss8250 { 58 struct dw8250_port_data data; 59 struct lpss8250_board *board; 60 61 /* DMA parameters */ 62 struct dw_dma_chip dma_chip; 63 struct dw_dma_slave dma_param; 64 u8 dma_maxburst; 65 }; 66 67 static inline struct lpss8250 *to_lpss8250(struct dw8250_port_data *data) 68 { 69 return container_of(data, struct lpss8250, data); 70 } 71 72 static void byt_set_termios(struct uart_port *p, struct ktermios *termios, 73 struct ktermios *old) 74 { 75 unsigned int baud = tty_termios_baud_rate(termios); 76 struct lpss8250 *lpss = to_lpss8250(p->private_data); 77 unsigned long fref = lpss->board->freq, fuart = baud * 16; 78 unsigned long w = BIT(15) - 1; 79 unsigned long m, n; 80 u32 reg; 81 82 /* Gracefully handle the B0 case: fall back to B9600 */ 83 fuart = fuart ? fuart : 9600 * 16; 84 85 /* Get Fuart closer to Fref */ 86 fuart *= rounddown_pow_of_two(fref / fuart); 87 88 /* 89 * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the 90 * dividers must be adjusted. 91 * 92 * uartclk = (m / n) * 100 MHz, where m <= n 93 */ 94 rational_best_approximation(fuart, fref, w, w, &m, &n); 95 p->uartclk = fuart; 96 97 /* Reset the clock */ 98 reg = (m << BYT_PRV_CLK_M_VAL_SHIFT) | (n << BYT_PRV_CLK_N_VAL_SHIFT); 99 writel(reg, p->membase + BYT_PRV_CLK); 100 reg |= BYT_PRV_CLK_EN | BYT_PRV_CLK_UPDATE; 101 writel(reg, p->membase + BYT_PRV_CLK); 102 103 p->status &= ~UPSTAT_AUTOCTS; 104 if (termios->c_cflag & CRTSCTS) 105 p->status |= UPSTAT_AUTOCTS; 106 107 serial8250_do_set_termios(p, termios, old); 108 } 109 110 static unsigned int byt_get_mctrl(struct uart_port *port) 111 { 112 unsigned int ret = serial8250_do_get_mctrl(port); 113 114 /* Force DCD and DSR signals to permanently be reported as active */ 115 ret |= TIOCM_CAR | TIOCM_DSR; 116 117 return ret; 118 } 119 120 static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port) 121 { 122 struct dw_dma_slave *param = &lpss->dma_param; 123 struct pci_dev *pdev = to_pci_dev(port->dev); 124 unsigned int dma_devfn = PCI_DEVFN(PCI_SLOT(pdev->devfn), 0); 125 struct pci_dev *dma_dev = pci_get_slot(pdev->bus, dma_devfn); 126 127 switch (pdev->device) { 128 case PCI_DEVICE_ID_INTEL_BYT_UART1: 129 case PCI_DEVICE_ID_INTEL_BSW_UART1: 130 case PCI_DEVICE_ID_INTEL_BDW_UART1: 131 param->src_id = 3; 132 param->dst_id = 2; 133 break; 134 case PCI_DEVICE_ID_INTEL_BYT_UART2: 135 case PCI_DEVICE_ID_INTEL_BSW_UART2: 136 case PCI_DEVICE_ID_INTEL_BDW_UART2: 137 param->src_id = 5; 138 param->dst_id = 4; 139 break; 140 default: 141 return -EINVAL; 142 } 143 144 param->dma_dev = &dma_dev->dev; 145 param->m_master = 0; 146 param->p_master = 1; 147 148 lpss->dma_maxburst = 16; 149 150 port->set_termios = byt_set_termios; 151 port->get_mctrl = byt_get_mctrl; 152 153 /* Disable TX counter interrupts */ 154 writel(BYT_TX_OVF_INT_MASK, port->membase + BYT_TX_OVF_INT); 155 156 return 0; 157 } 158 159 #ifdef CONFIG_SERIAL_8250_DMA 160 static const struct dw_dma_platform_data qrk_serial_dma_pdata = { 161 .nr_channels = 2, 162 .chan_allocation_order = CHAN_ALLOCATION_ASCENDING, 163 .chan_priority = CHAN_PRIORITY_ASCENDING, 164 .block_size = 4095, 165 .nr_masters = 1, 166 .data_width = {4}, 167 .multi_block = {0}, 168 }; 169 170 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) 171 { 172 struct uart_8250_dma *dma = &lpss->data.dma; 173 struct dw_dma_chip *chip = &lpss->dma_chip; 174 struct dw_dma_slave *param = &lpss->dma_param; 175 struct pci_dev *pdev = to_pci_dev(port->dev); 176 int ret; 177 178 chip->pdata = &qrk_serial_dma_pdata; 179 chip->dev = &pdev->dev; 180 chip->id = pdev->devfn; 181 chip->irq = pci_irq_vector(pdev, 0); 182 chip->regs = pci_ioremap_bar(pdev, 1); 183 if (!chip->regs) 184 return; 185 186 /* Falling back to PIO mode if DMA probing fails */ 187 ret = dw_dma_probe(chip); 188 if (ret) 189 return; 190 191 pci_try_set_mwi(pdev); 192 193 /* Special DMA address for UART */ 194 dma->rx_dma_addr = 0xfffff000; 195 dma->tx_dma_addr = 0xfffff000; 196 197 param->dma_dev = &pdev->dev; 198 param->src_id = 0; 199 param->dst_id = 1; 200 param->hs_polarity = true; 201 202 lpss->dma_maxburst = 8; 203 } 204 205 static void qrk_serial_exit_dma(struct lpss8250 *lpss) 206 { 207 struct dw_dma_chip *chip = &lpss->dma_chip; 208 struct dw_dma_slave *param = &lpss->dma_param; 209 210 if (!param->dma_dev) 211 return; 212 213 dw_dma_remove(chip); 214 215 pci_iounmap(to_pci_dev(chip->dev), chip->regs); 216 } 217 #else /* CONFIG_SERIAL_8250_DMA */ 218 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) {} 219 static void qrk_serial_exit_dma(struct lpss8250 *lpss) {} 220 #endif /* !CONFIG_SERIAL_8250_DMA */ 221 222 static int qrk_serial_setup(struct lpss8250 *lpss, struct uart_port *port) 223 { 224 qrk_serial_setup_dma(lpss, port); 225 return 0; 226 } 227 228 static void qrk_serial_exit(struct lpss8250 *lpss) 229 { 230 qrk_serial_exit_dma(lpss); 231 } 232 233 static bool lpss8250_dma_filter(struct dma_chan *chan, void *param) 234 { 235 struct dw_dma_slave *dws = param; 236 237 if (dws->dma_dev != chan->device->dev) 238 return false; 239 240 chan->private = dws; 241 return true; 242 } 243 244 static int lpss8250_dma_setup(struct lpss8250 *lpss, struct uart_8250_port *port) 245 { 246 struct uart_8250_dma *dma = &lpss->data.dma; 247 struct dw_dma_slave *rx_param, *tx_param; 248 struct device *dev = port->port.dev; 249 250 if (!lpss->dma_param.dma_dev) 251 return 0; 252 253 rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL); 254 if (!rx_param) 255 return -ENOMEM; 256 257 tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL); 258 if (!tx_param) 259 return -ENOMEM; 260 261 *rx_param = lpss->dma_param; 262 dma->rxconf.src_maxburst = lpss->dma_maxburst; 263 264 *tx_param = lpss->dma_param; 265 dma->txconf.dst_maxburst = lpss->dma_maxburst; 266 267 dma->fn = lpss8250_dma_filter; 268 dma->rx_param = rx_param; 269 dma->tx_param = tx_param; 270 271 port->dma = dma; 272 return 0; 273 } 274 275 static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id) 276 { 277 struct uart_8250_port uart; 278 struct lpss8250 *lpss; 279 int ret; 280 281 ret = pcim_enable_device(pdev); 282 if (ret) 283 return ret; 284 285 pci_set_master(pdev); 286 287 lpss = devm_kzalloc(&pdev->dev, sizeof(*lpss), GFP_KERNEL); 288 if (!lpss) 289 return -ENOMEM; 290 291 ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES); 292 if (ret < 0) 293 return ret; 294 295 lpss->board = (struct lpss8250_board *)id->driver_data; 296 297 memset(&uart, 0, sizeof(struct uart_8250_port)); 298 299 uart.port.dev = &pdev->dev; 300 uart.port.irq = pci_irq_vector(pdev, 0); 301 uart.port.private_data = &lpss->data; 302 uart.port.type = PORT_16550A; 303 uart.port.iotype = UPIO_MEM; 304 uart.port.regshift = 2; 305 uart.port.uartclk = lpss->board->base_baud * 16; 306 uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE; 307 uart.capabilities = UART_CAP_FIFO | UART_CAP_AFE; 308 uart.port.mapbase = pci_resource_start(pdev, 0); 309 uart.port.membase = pcim_iomap(pdev, 0, 0); 310 if (!uart.port.membase) 311 return -ENOMEM; 312 313 ret = lpss->board->setup(lpss, &uart.port); 314 if (ret) 315 return ret; 316 317 dw8250_setup_port(&uart.port); 318 319 ret = lpss8250_dma_setup(lpss, &uart); 320 if (ret) 321 goto err_exit; 322 323 ret = serial8250_register_8250_port(&uart); 324 if (ret < 0) 325 goto err_exit; 326 327 lpss->data.line = ret; 328 329 pci_set_drvdata(pdev, lpss); 330 return 0; 331 332 err_exit: 333 if (lpss->board->exit) 334 lpss->board->exit(lpss); 335 pci_free_irq_vectors(pdev); 336 return ret; 337 } 338 339 static void lpss8250_remove(struct pci_dev *pdev) 340 { 341 struct lpss8250 *lpss = pci_get_drvdata(pdev); 342 343 serial8250_unregister_port(lpss->data.line); 344 345 if (lpss->board->exit) 346 lpss->board->exit(lpss); 347 pci_free_irq_vectors(pdev); 348 } 349 350 static const struct lpss8250_board byt_board = { 351 .freq = 100000000, 352 .base_baud = 2764800, 353 .setup = byt_serial_setup, 354 }; 355 356 static const struct lpss8250_board ehl_board = { 357 .freq = 200000000, 358 .base_baud = 12500000, 359 }; 360 361 static const struct lpss8250_board qrk_board = { 362 .freq = 44236800, 363 .base_baud = 2764800, 364 .setup = qrk_serial_setup, 365 .exit = qrk_serial_exit, 366 }; 367 368 static const struct pci_device_id pci_ids[] = { 369 { PCI_DEVICE_DATA(INTEL, QRK_UARTx, &qrk_board) }, 370 { PCI_DEVICE_DATA(INTEL, EHL_UART0, &ehl_board) }, 371 { PCI_DEVICE_DATA(INTEL, EHL_UART1, &ehl_board) }, 372 { PCI_DEVICE_DATA(INTEL, EHL_UART2, &ehl_board) }, 373 { PCI_DEVICE_DATA(INTEL, EHL_UART3, &ehl_board) }, 374 { PCI_DEVICE_DATA(INTEL, EHL_UART4, &ehl_board) }, 375 { PCI_DEVICE_DATA(INTEL, EHL_UART5, &ehl_board) }, 376 { PCI_DEVICE_DATA(INTEL, BYT_UART1, &byt_board) }, 377 { PCI_DEVICE_DATA(INTEL, BYT_UART2, &byt_board) }, 378 { PCI_DEVICE_DATA(INTEL, BSW_UART1, &byt_board) }, 379 { PCI_DEVICE_DATA(INTEL, BSW_UART2, &byt_board) }, 380 { PCI_DEVICE_DATA(INTEL, BDW_UART1, &byt_board) }, 381 { PCI_DEVICE_DATA(INTEL, BDW_UART2, &byt_board) }, 382 { } 383 }; 384 MODULE_DEVICE_TABLE(pci, pci_ids); 385 386 static struct pci_driver lpss8250_pci_driver = { 387 .name = "8250_lpss", 388 .id_table = pci_ids, 389 .probe = lpss8250_probe, 390 .remove = lpss8250_remove, 391 }; 392 393 module_pci_driver(lpss8250_pci_driver); 394 395 MODULE_AUTHOR("Intel Corporation"); 396 MODULE_LICENSE("GPL v2"); 397 MODULE_DESCRIPTION("Intel LPSS UART driver"); 398