1 /* 2 * 8250_lpss.c - Driver for UART on Intel Braswell and various other Intel SoCs 3 * 4 * Copyright (C) 2016 Intel Corporation 5 * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 12 #include <linux/bitops.h> 13 #include <linux/module.h> 14 #include <linux/pci.h> 15 #include <linux/rational.h> 16 17 #include <linux/dmaengine.h> 18 #include <linux/dma/dw.h> 19 20 #include "8250.h" 21 22 #define PCI_DEVICE_ID_INTEL_QRK_UARTx 0x0936 23 24 #define PCI_DEVICE_ID_INTEL_BYT_UART1 0x0f0a 25 #define PCI_DEVICE_ID_INTEL_BYT_UART2 0x0f0c 26 27 #define PCI_DEVICE_ID_INTEL_BSW_UART1 0x228a 28 #define PCI_DEVICE_ID_INTEL_BSW_UART2 0x228c 29 30 #define PCI_DEVICE_ID_INTEL_BDW_UART1 0x9ce3 31 #define PCI_DEVICE_ID_INTEL_BDW_UART2 0x9ce4 32 33 /* Intel LPSS specific registers */ 34 35 #define BYT_PRV_CLK 0x800 36 #define BYT_PRV_CLK_EN BIT(0) 37 #define BYT_PRV_CLK_M_VAL_SHIFT 1 38 #define BYT_PRV_CLK_N_VAL_SHIFT 16 39 #define BYT_PRV_CLK_UPDATE BIT(31) 40 41 #define BYT_TX_OVF_INT 0x820 42 #define BYT_TX_OVF_INT_MASK BIT(1) 43 44 struct lpss8250; 45 46 struct lpss8250_board { 47 unsigned long freq; 48 unsigned int base_baud; 49 int (*setup)(struct lpss8250 *, struct uart_port *p); 50 void (*exit)(struct lpss8250 *); 51 }; 52 53 struct lpss8250 { 54 int line; 55 struct lpss8250_board *board; 56 57 /* DMA parameters */ 58 struct uart_8250_dma dma; 59 struct dw_dma_chip dma_chip; 60 struct dw_dma_slave dma_param; 61 u8 dma_maxburst; 62 }; 63 64 static void byt_set_termios(struct uart_port *p, struct ktermios *termios, 65 struct ktermios *old) 66 { 67 unsigned int baud = tty_termios_baud_rate(termios); 68 struct lpss8250 *lpss = p->private_data; 69 unsigned long fref = lpss->board->freq, fuart = baud * 16; 70 unsigned long w = BIT(15) - 1; 71 unsigned long m, n; 72 u32 reg; 73 74 /* Gracefully handle the B0 case: fall back to B9600 */ 75 fuart = fuart ? fuart : 9600 * 16; 76 77 /* Get Fuart closer to Fref */ 78 fuart *= rounddown_pow_of_two(fref / fuart); 79 80 /* 81 * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the 82 * dividers must be adjusted. 83 * 84 * uartclk = (m / n) * 100 MHz, where m <= n 85 */ 86 rational_best_approximation(fuart, fref, w, w, &m, &n); 87 p->uartclk = fuart; 88 89 /* Reset the clock */ 90 reg = (m << BYT_PRV_CLK_M_VAL_SHIFT) | (n << BYT_PRV_CLK_N_VAL_SHIFT); 91 writel(reg, p->membase + BYT_PRV_CLK); 92 reg |= BYT_PRV_CLK_EN | BYT_PRV_CLK_UPDATE; 93 writel(reg, p->membase + BYT_PRV_CLK); 94 95 p->status &= ~UPSTAT_AUTOCTS; 96 if (termios->c_cflag & CRTSCTS) 97 p->status |= UPSTAT_AUTOCTS; 98 99 serial8250_do_set_termios(p, termios, old); 100 } 101 102 static unsigned int byt_get_mctrl(struct uart_port *port) 103 { 104 unsigned int ret = serial8250_do_get_mctrl(port); 105 106 /* Force DCD and DSR signals to permanently be reported as active */ 107 ret |= TIOCM_CAR | TIOCM_DSR; 108 109 return ret; 110 } 111 112 static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port) 113 { 114 struct dw_dma_slave *param = &lpss->dma_param; 115 struct uart_8250_port *up = up_to_u8250p(port); 116 struct pci_dev *pdev = to_pci_dev(port->dev); 117 unsigned int dma_devfn = PCI_DEVFN(PCI_SLOT(pdev->devfn), 0); 118 struct pci_dev *dma_dev = pci_get_slot(pdev->bus, dma_devfn); 119 120 switch (pdev->device) { 121 case PCI_DEVICE_ID_INTEL_BYT_UART1: 122 case PCI_DEVICE_ID_INTEL_BSW_UART1: 123 case PCI_DEVICE_ID_INTEL_BDW_UART1: 124 param->src_id = 3; 125 param->dst_id = 2; 126 break; 127 case PCI_DEVICE_ID_INTEL_BYT_UART2: 128 case PCI_DEVICE_ID_INTEL_BSW_UART2: 129 case PCI_DEVICE_ID_INTEL_BDW_UART2: 130 param->src_id = 5; 131 param->dst_id = 4; 132 break; 133 default: 134 return -EINVAL; 135 } 136 137 param->dma_dev = &dma_dev->dev; 138 param->m_master = 0; 139 param->p_master = 1; 140 141 /* TODO: Detect FIFO size automaticaly for DesignWare 8250 */ 142 port->fifosize = 64; 143 up->tx_loadsz = 64; 144 145 lpss->dma_maxburst = 16; 146 147 port->set_termios = byt_set_termios; 148 port->get_mctrl = byt_get_mctrl; 149 150 /* Disable TX counter interrupts */ 151 writel(BYT_TX_OVF_INT_MASK, port->membase + BYT_TX_OVF_INT); 152 153 return 0; 154 } 155 156 #ifdef CONFIG_SERIAL_8250_DMA 157 static const struct dw_dma_platform_data qrk_serial_dma_pdata = { 158 .nr_channels = 2, 159 .is_private = true, 160 .chan_allocation_order = CHAN_ALLOCATION_ASCENDING, 161 .chan_priority = CHAN_PRIORITY_ASCENDING, 162 .block_size = 4095, 163 .nr_masters = 1, 164 .data_width = {4}, 165 .multi_block = {0}, 166 }; 167 168 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) 169 { 170 struct uart_8250_dma *dma = &lpss->dma; 171 struct dw_dma_chip *chip = &lpss->dma_chip; 172 struct dw_dma_slave *param = &lpss->dma_param; 173 struct pci_dev *pdev = to_pci_dev(port->dev); 174 int ret; 175 176 chip->dev = &pdev->dev; 177 chip->irq = pci_irq_vector(pdev, 0); 178 chip->regs = pci_ioremap_bar(pdev, 1); 179 chip->pdata = &qrk_serial_dma_pdata; 180 181 /* Falling back to PIO mode if DMA probing fails */ 182 ret = dw_dma_probe(chip); 183 if (ret) 184 return; 185 186 pci_try_set_mwi(pdev); 187 188 /* Special DMA address for UART */ 189 dma->rx_dma_addr = 0xfffff000; 190 dma->tx_dma_addr = 0xfffff000; 191 192 param->dma_dev = &pdev->dev; 193 param->src_id = 0; 194 param->dst_id = 1; 195 param->hs_polarity = true; 196 197 lpss->dma_maxburst = 8; 198 } 199 200 static void qrk_serial_exit_dma(struct lpss8250 *lpss) 201 { 202 struct dw_dma_slave *param = &lpss->dma_param; 203 204 if (!param->dma_dev) 205 return; 206 dw_dma_remove(&lpss->dma_chip); 207 } 208 #else /* CONFIG_SERIAL_8250_DMA */ 209 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) {} 210 static void qrk_serial_exit_dma(struct lpss8250 *lpss) {} 211 #endif /* !CONFIG_SERIAL_8250_DMA */ 212 213 static int qrk_serial_setup(struct lpss8250 *lpss, struct uart_port *port) 214 { 215 struct pci_dev *pdev = to_pci_dev(port->dev); 216 int ret; 217 218 pci_set_master(pdev); 219 220 ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES); 221 if (ret < 0) 222 return ret; 223 224 port->irq = pci_irq_vector(pdev, 0); 225 226 qrk_serial_setup_dma(lpss, port); 227 return 0; 228 } 229 230 static void qrk_serial_exit(struct lpss8250 *lpss) 231 { 232 qrk_serial_exit_dma(lpss); 233 } 234 235 static bool lpss8250_dma_filter(struct dma_chan *chan, void *param) 236 { 237 struct dw_dma_slave *dws = param; 238 239 if (dws->dma_dev != chan->device->dev) 240 return false; 241 242 chan->private = dws; 243 return true; 244 } 245 246 static int lpss8250_dma_setup(struct lpss8250 *lpss, struct uart_8250_port *port) 247 { 248 struct uart_8250_dma *dma = &lpss->dma; 249 struct dw_dma_slave *rx_param, *tx_param; 250 struct device *dev = port->port.dev; 251 252 if (!lpss->dma_param.dma_dev) 253 return 0; 254 255 rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL); 256 if (!rx_param) 257 return -ENOMEM; 258 259 tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL); 260 if (!tx_param) 261 return -ENOMEM; 262 263 *rx_param = lpss->dma_param; 264 dma->rxconf.src_maxburst = lpss->dma_maxburst; 265 266 *tx_param = lpss->dma_param; 267 dma->txconf.dst_maxburst = lpss->dma_maxburst; 268 269 dma->fn = lpss8250_dma_filter; 270 dma->rx_param = rx_param; 271 dma->tx_param = tx_param; 272 273 port->dma = dma; 274 return 0; 275 } 276 277 static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id) 278 { 279 struct uart_8250_port uart; 280 struct lpss8250 *lpss; 281 int ret; 282 283 ret = pcim_enable_device(pdev); 284 if (ret) 285 return ret; 286 287 lpss = devm_kzalloc(&pdev->dev, sizeof(*lpss), GFP_KERNEL); 288 if (!lpss) 289 return -ENOMEM; 290 291 lpss->board = (struct lpss8250_board *)id->driver_data; 292 293 memset(&uart, 0, sizeof(struct uart_8250_port)); 294 295 uart.port.dev = &pdev->dev; 296 uart.port.irq = pdev->irq; 297 uart.port.private_data = lpss; 298 uart.port.type = PORT_16550A; 299 uart.port.iotype = UPIO_MEM; 300 uart.port.regshift = 2; 301 uart.port.uartclk = lpss->board->base_baud * 16; 302 uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE; 303 uart.capabilities = UART_CAP_FIFO | UART_CAP_AFE; 304 uart.port.mapbase = pci_resource_start(pdev, 0); 305 uart.port.membase = pcim_iomap(pdev, 0, 0); 306 if (!uart.port.membase) 307 return -ENOMEM; 308 309 ret = lpss->board->setup(lpss, &uart.port); 310 if (ret) 311 return ret; 312 313 ret = lpss8250_dma_setup(lpss, &uart); 314 if (ret) 315 goto err_exit; 316 317 ret = serial8250_register_8250_port(&uart); 318 if (ret < 0) 319 goto err_exit; 320 321 lpss->line = ret; 322 323 pci_set_drvdata(pdev, lpss); 324 return 0; 325 326 err_exit: 327 if (lpss->board->exit) 328 lpss->board->exit(lpss); 329 return ret; 330 } 331 332 static void lpss8250_remove(struct pci_dev *pdev) 333 { 334 struct lpss8250 *lpss = pci_get_drvdata(pdev); 335 336 serial8250_unregister_port(lpss->line); 337 338 if (lpss->board->exit) 339 lpss->board->exit(lpss); 340 } 341 342 static const struct lpss8250_board byt_board = { 343 .freq = 100000000, 344 .base_baud = 2764800, 345 .setup = byt_serial_setup, 346 }; 347 348 static const struct lpss8250_board qrk_board = { 349 .freq = 44236800, 350 .base_baud = 2764800, 351 .setup = qrk_serial_setup, 352 .exit = qrk_serial_exit, 353 }; 354 355 #define LPSS_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board } 356 357 static const struct pci_device_id pci_ids[] = { 358 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_QRK_UARTx, qrk_board), 359 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART1, byt_board), 360 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART2, byt_board), 361 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART1, byt_board), 362 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART2, byt_board), 363 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART1, byt_board), 364 LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART2, byt_board), 365 { }, 366 }; 367 MODULE_DEVICE_TABLE(pci, pci_ids); 368 369 static struct pci_driver lpss8250_pci_driver = { 370 .name = "8250_lpss", 371 .id_table = pci_ids, 372 .probe = lpss8250_probe, 373 .remove = lpss8250_remove, 374 }; 375 376 module_pci_driver(lpss8250_pci_driver); 377 378 MODULE_AUTHOR("Intel Corporation"); 379 MODULE_LICENSE("GPL v2"); 380 MODULE_DESCRIPTION("Intel LPSS UART driver"); 381