1 /* 2 * 8250_mid.c - Driver for UART on Intel Penwell and various other Intel SOCs 3 * 4 * Copyright (C) 2015 Intel Corporation 5 * Author: Heikki Krogerus <heikki.krogerus@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/dma/hsu.h> 18 #include <linux/8250_pci.h> 19 20 #include "8250.h" 21 22 #define PCI_DEVICE_ID_INTEL_PNW_UART1 0x081b 23 #define PCI_DEVICE_ID_INTEL_PNW_UART2 0x081c 24 #define PCI_DEVICE_ID_INTEL_PNW_UART3 0x081d 25 #define PCI_DEVICE_ID_INTEL_TNG_UART 0x1191 26 #define PCI_DEVICE_ID_INTEL_DNV_UART 0x19d8 27 28 /* Intel MID Specific registers */ 29 #define INTEL_MID_UART_DNV_FISR 0x08 30 #define INTEL_MID_UART_PS 0x30 31 #define INTEL_MID_UART_MUL 0x34 32 #define INTEL_MID_UART_DIV 0x38 33 34 struct mid8250; 35 36 struct mid8250_board { 37 unsigned int flags; 38 unsigned long freq; 39 unsigned int base_baud; 40 int (*setup)(struct mid8250 *, struct uart_port *p); 41 void (*exit)(struct mid8250 *); 42 }; 43 44 struct mid8250 { 45 int line; 46 int dma_index; 47 struct pci_dev *dma_dev; 48 struct uart_8250_dma dma; 49 struct mid8250_board *board; 50 struct hsu_dma_chip dma_chip; 51 }; 52 53 /*****************************************************************************/ 54 55 static int pnw_setup(struct mid8250 *mid, struct uart_port *p) 56 { 57 struct pci_dev *pdev = to_pci_dev(p->dev); 58 59 switch (pdev->device) { 60 case PCI_DEVICE_ID_INTEL_PNW_UART1: 61 mid->dma_index = 0; 62 break; 63 case PCI_DEVICE_ID_INTEL_PNW_UART2: 64 mid->dma_index = 1; 65 break; 66 case PCI_DEVICE_ID_INTEL_PNW_UART3: 67 mid->dma_index = 2; 68 break; 69 default: 70 return -EINVAL; 71 } 72 73 mid->dma_dev = pci_get_slot(pdev->bus, 74 PCI_DEVFN(PCI_SLOT(pdev->devfn), 3)); 75 return 0; 76 } 77 78 static int tng_setup(struct mid8250 *mid, struct uart_port *p) 79 { 80 struct pci_dev *pdev = to_pci_dev(p->dev); 81 int index = PCI_FUNC(pdev->devfn); 82 83 /* 84 * Device 0000:00:04.0 is not a real HSU port. It provides a global 85 * register set for all HSU ports, although it has the same PCI ID. 86 * Skip it here. 87 */ 88 if (index-- == 0) 89 return -ENODEV; 90 91 mid->dma_index = index; 92 mid->dma_dev = pci_get_slot(pdev->bus, PCI_DEVFN(5, 0)); 93 return 0; 94 } 95 96 static int dnv_handle_irq(struct uart_port *p) 97 { 98 struct mid8250 *mid = p->private_data; 99 struct uart_8250_port *up = up_to_u8250p(p); 100 unsigned int fisr = serial_port_in(p, INTEL_MID_UART_DNV_FISR); 101 u32 status; 102 int ret = IRQ_NONE; 103 int err; 104 105 if (fisr & BIT(2)) { 106 err = hsu_dma_get_status(&mid->dma_chip, 1, &status); 107 if (err > 0) { 108 serial8250_rx_dma_flush(up); 109 ret |= IRQ_HANDLED; 110 } else if (err == 0) 111 ret |= hsu_dma_do_irq(&mid->dma_chip, 1, status); 112 } 113 if (fisr & BIT(1)) { 114 err = hsu_dma_get_status(&mid->dma_chip, 0, &status); 115 if (err > 0) 116 ret |= IRQ_HANDLED; 117 else if (err == 0) 118 ret |= hsu_dma_do_irq(&mid->dma_chip, 0, status); 119 } 120 if (fisr & BIT(0)) 121 ret |= serial8250_handle_irq(p, serial_port_in(p, UART_IIR)); 122 return ret; 123 } 124 125 #define DNV_DMA_CHAN_OFFSET 0x80 126 127 static int dnv_setup(struct mid8250 *mid, struct uart_port *p) 128 { 129 struct hsu_dma_chip *chip = &mid->dma_chip; 130 struct pci_dev *pdev = to_pci_dev(p->dev); 131 unsigned int bar = FL_GET_BASE(mid->board->flags); 132 int ret; 133 134 chip->dev = &pdev->dev; 135 chip->irq = pdev->irq; 136 chip->regs = p->membase; 137 chip->length = pci_resource_len(pdev, bar); 138 chip->offset = DNV_DMA_CHAN_OFFSET; 139 140 /* Falling back to PIO mode if DMA probing fails */ 141 ret = hsu_dma_probe(chip); 142 if (ret) 143 return 0; 144 145 mid->dma_dev = pdev; 146 147 p->handle_irq = dnv_handle_irq; 148 return 0; 149 } 150 151 static void dnv_exit(struct mid8250 *mid) 152 { 153 if (!mid->dma_dev) 154 return; 155 hsu_dma_remove(&mid->dma_chip); 156 } 157 158 /*****************************************************************************/ 159 160 static void mid8250_set_termios(struct uart_port *p, 161 struct ktermios *termios, 162 struct ktermios *old) 163 { 164 unsigned int baud = tty_termios_baud_rate(termios); 165 struct mid8250 *mid = p->private_data; 166 unsigned short ps = 16; 167 unsigned long fuart = baud * ps; 168 unsigned long w = BIT(24) - 1; 169 unsigned long mul, div; 170 171 /* Gracefully handle the B0 case: fall back to B9600 */ 172 fuart = fuart ? fuart : 9600 * 16; 173 174 if (mid->board->freq < fuart) { 175 /* Find prescaler value that satisfies Fuart < Fref */ 176 if (mid->board->freq > baud) 177 ps = mid->board->freq / baud; /* baud rate too high */ 178 else 179 ps = 1; /* PLL case */ 180 fuart = baud * ps; 181 } else { 182 /* Get Fuart closer to Fref */ 183 fuart *= rounddown_pow_of_two(mid->board->freq / fuart); 184 } 185 186 rational_best_approximation(fuart, mid->board->freq, w, w, &mul, &div); 187 p->uartclk = fuart * 16 / ps; /* core uses ps = 16 always */ 188 189 writel(ps, p->membase + INTEL_MID_UART_PS); /* set PS */ 190 writel(mul, p->membase + INTEL_MID_UART_MUL); /* set MUL */ 191 writel(div, p->membase + INTEL_MID_UART_DIV); 192 193 serial8250_do_set_termios(p, termios, old); 194 } 195 196 static bool mid8250_dma_filter(struct dma_chan *chan, void *param) 197 { 198 struct hsu_dma_slave *s = param; 199 200 if (s->dma_dev != chan->device->dev || s->chan_id != chan->chan_id) 201 return false; 202 203 chan->private = s; 204 return true; 205 } 206 207 static int mid8250_dma_setup(struct mid8250 *mid, struct uart_8250_port *port) 208 { 209 struct uart_8250_dma *dma = &mid->dma; 210 struct device *dev = port->port.dev; 211 struct hsu_dma_slave *rx_param; 212 struct hsu_dma_slave *tx_param; 213 214 if (!mid->dma_dev) 215 return 0; 216 217 rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL); 218 if (!rx_param) 219 return -ENOMEM; 220 221 tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL); 222 if (!tx_param) 223 return -ENOMEM; 224 225 rx_param->chan_id = mid->dma_index * 2 + 1; 226 tx_param->chan_id = mid->dma_index * 2; 227 228 dma->rxconf.src_maxburst = 64; 229 dma->txconf.dst_maxburst = 64; 230 231 rx_param->dma_dev = &mid->dma_dev->dev; 232 tx_param->dma_dev = &mid->dma_dev->dev; 233 234 dma->fn = mid8250_dma_filter; 235 dma->rx_param = rx_param; 236 dma->tx_param = tx_param; 237 238 port->dma = dma; 239 return 0; 240 } 241 242 static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id) 243 { 244 struct uart_8250_port uart; 245 struct mid8250 *mid; 246 unsigned int bar; 247 int ret; 248 249 ret = pcim_enable_device(pdev); 250 if (ret) 251 return ret; 252 253 pci_set_master(pdev); 254 255 mid = devm_kzalloc(&pdev->dev, sizeof(*mid), GFP_KERNEL); 256 if (!mid) 257 return -ENOMEM; 258 259 mid->board = (struct mid8250_board *)id->driver_data; 260 bar = FL_GET_BASE(mid->board->flags); 261 262 memset(&uart, 0, sizeof(struct uart_8250_port)); 263 264 uart.port.dev = &pdev->dev; 265 uart.port.irq = pdev->irq; 266 uart.port.private_data = mid; 267 uart.port.type = PORT_16750; 268 uart.port.iotype = UPIO_MEM; 269 uart.port.uartclk = mid->board->base_baud * 16; 270 uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE; 271 uart.port.set_termios = mid8250_set_termios; 272 273 uart.port.mapbase = pci_resource_start(pdev, bar); 274 uart.port.membase = pcim_iomap(pdev, bar, 0); 275 if (!uart.port.membase) 276 return -ENOMEM; 277 278 if (mid->board->setup) { 279 ret = mid->board->setup(mid, &uart.port); 280 if (ret) 281 return ret; 282 } 283 284 ret = mid8250_dma_setup(mid, &uart); 285 if (ret) 286 goto err; 287 288 ret = serial8250_register_8250_port(&uart); 289 if (ret < 0) 290 goto err; 291 292 mid->line = ret; 293 294 pci_set_drvdata(pdev, mid); 295 return 0; 296 err: 297 if (mid->board->exit) 298 mid->board->exit(mid); 299 return ret; 300 } 301 302 static void mid8250_remove(struct pci_dev *pdev) 303 { 304 struct mid8250 *mid = pci_get_drvdata(pdev); 305 306 if (mid->board->exit) 307 mid->board->exit(mid); 308 309 serial8250_unregister_port(mid->line); 310 } 311 312 static const struct mid8250_board pnw_board = { 313 .flags = FL_BASE0, 314 .freq = 50000000, 315 .base_baud = 115200, 316 .setup = pnw_setup, 317 }; 318 319 static const struct mid8250_board tng_board = { 320 .flags = FL_BASE0, 321 .freq = 38400000, 322 .base_baud = 1843200, 323 .setup = tng_setup, 324 }; 325 326 static const struct mid8250_board dnv_board = { 327 .flags = FL_BASE1, 328 .freq = 133333333, 329 .base_baud = 115200, 330 .setup = dnv_setup, 331 .exit = dnv_exit, 332 }; 333 334 #define MID_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board } 335 336 static const struct pci_device_id pci_ids[] = { 337 MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART1, pnw_board), 338 MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART2, pnw_board), 339 MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART3, pnw_board), 340 MID_DEVICE(PCI_DEVICE_ID_INTEL_TNG_UART, tng_board), 341 MID_DEVICE(PCI_DEVICE_ID_INTEL_DNV_UART, dnv_board), 342 { }, 343 }; 344 MODULE_DEVICE_TABLE(pci, pci_ids); 345 346 static struct pci_driver mid8250_pci_driver = { 347 .name = "8250_mid", 348 .id_table = pci_ids, 349 .probe = mid8250_probe, 350 .remove = mid8250_remove, 351 }; 352 353 module_pci_driver(mid8250_pci_driver); 354 355 MODULE_AUTHOR("Intel Corporation"); 356 MODULE_LICENSE("GPL v2"); 357 MODULE_DESCRIPTION("Intel MID UART driver"); 358