drivers/tty/serial/8250/8250_mid.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * 8250_mid.c - Driver for UART on Intel Penwell and various other Intel SOCs
   4  *
   5  * Copyright (C) 2015 Intel Corporation
   6  * Author: Heikki Krogerus <heikki.krogerus@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/dma/hsu.h>
  15 #include <linux/8250_pci.h>
  16
  17 #include "8250.h"
  18
  19 #define PCI_DEVICE_ID_INTEL_PNW_UART1   0x081b
  20 #define PCI_DEVICE_ID_INTEL_PNW_UART2   0x081c
  21 #define PCI_DEVICE_ID_INTEL_PNW_UART3   0x081d
  22 #define PCI_DEVICE_ID_INTEL_TNG_UART    0x1191
  23 #define PCI_DEVICE_ID_INTEL_CDF_UART    0x18d8
  24 #define PCI_DEVICE_ID_INTEL_DNV_UART    0x19d8
  25
  26 /* Intel MID Specific registers */
  27 #define INTEL_MID_UART_FISR             0x08
  28 #define INTEL_MID_UART_PS               0x30
  29 #define INTEL_MID_UART_MUL              0x34
  30 #define INTEL_MID_UART_DIV              0x38
  31
  32 struct mid8250;
  33
  34 struct mid8250_board {
  35         unsigned int flags;
  36         unsigned long freq;
  37         unsigned int base_baud;
  38         int (*setup)(struct mid8250 *, struct uart_port *p);
  39         void (*exit)(struct mid8250 *);
  40 };
  41
  42 struct mid8250 {
  43         int line;
  44         int dma_index;
  45         struct pci_dev *dma_dev;
  46         struct uart_8250_dma dma;
  47         struct mid8250_board *board;
  48         struct hsu_dma_chip dma_chip;
  49 };
  50
  51 /*****************************************************************************/
  52
  53 static int pnw_setup(struct mid8250 *mid, struct uart_port *p)
  54 {
  55         struct pci_dev *pdev = to_pci_dev(p->dev);
  56
  57         switch (pdev->device) {
  58         case PCI_DEVICE_ID_INTEL_PNW_UART1:
  59                 mid->dma_index = 0;
  60                 break;
  61         case PCI_DEVICE_ID_INTEL_PNW_UART2:
  62                 mid->dma_index = 1;
  63                 break;
  64         case PCI_DEVICE_ID_INTEL_PNW_UART3:
  65                 mid->dma_index = 2;
  66                 break;
  67         default:
  68                 return -EINVAL;
  69         }
  70
  71         mid->dma_dev = pci_get_slot(pdev->bus,
  72                                     PCI_DEVFN(PCI_SLOT(pdev->devfn), 3));
  73         return 0;
  74 }
  75
  76 static int tng_handle_irq(struct uart_port *p)
  77 {
  78         struct mid8250 *mid = p->private_data;
  79         struct uart_8250_port *up = up_to_u8250p(p);
  80         struct hsu_dma_chip *chip;
  81         u32 status;
  82         int ret = 0;
  83         int err;
  84
  85         chip = pci_get_drvdata(mid->dma_dev);
  86
  87         /* Rx DMA */
  88         err = hsu_dma_get_status(chip, mid->dma_index * 2 + 1, &status);
  89         if (err > 0) {
  90                 serial8250_rx_dma_flush(up);
  91                 ret |= 1;
  92         } else if (err == 0)
  93                 ret |= hsu_dma_do_irq(chip, mid->dma_index * 2 + 1, status);
  94
  95         /* Tx DMA */
  96         err = hsu_dma_get_status(chip, mid->dma_index * 2, &status);
  97         if (err > 0)
  98                 ret |= 1;
  99         else if (err == 0)
 100                 ret |= hsu_dma_do_irq(chip, mid->dma_index * 2, status);
 101
 102         /* UART */
 103         ret |= serial8250_handle_irq(p, serial_port_in(p, UART_IIR));
 104         return IRQ_RETVAL(ret);
 105 }
 106
 107 static int tng_setup(struct mid8250 *mid, struct uart_port *p)
 108 {
 109         struct pci_dev *pdev = to_pci_dev(p->dev);
 110         int index = PCI_FUNC(pdev->devfn);
 111
 112         /*
 113          * Device 0000:00:04.0 is not a real HSU port. It provides a global
 114          * register set for all HSU ports, although it has the same PCI ID.
 115          * Skip it here.
 116          */
 117         if (index-- == 0)
 118                 return -ENODEV;
 119
 120         mid->dma_index = index;
 121         mid->dma_dev = pci_get_slot(pdev->bus, PCI_DEVFN(5, 0));
 122
 123         p->handle_irq = tng_handle_irq;
 124         return 0;
 125 }
 126
 127 static int dnv_handle_irq(struct uart_port *p)
 128 {
 129         struct mid8250 *mid = p->private_data;
 130         struct uart_8250_port *up = up_to_u8250p(p);
 131         unsigned int fisr = serial_port_in(p, INTEL_MID_UART_FISR);
 132         u32 status;
 133         int ret = 0;
 134         int err;
 135
 136         if (fisr & BIT(2)) {
 137                 err = hsu_dma_get_status(&mid->dma_chip, 1, &status);
 138                 if (err > 0) {
 139                         serial8250_rx_dma_flush(up);
 140                         ret |= 1;
 141                 } else if (err == 0)
 142                         ret |= hsu_dma_do_irq(&mid->dma_chip, 1, status);
 143         }
 144         if (fisr & BIT(1)) {
 145                 err = hsu_dma_get_status(&mid->dma_chip, 0, &status);
 146                 if (err > 0)
 147                         ret |= 1;
 148                 else if (err == 0)
 149                         ret |= hsu_dma_do_irq(&mid->dma_chip, 0, status);
 150         }
 151         if (fisr & BIT(0))
 152                 ret |= serial8250_handle_irq(p, serial_port_in(p, UART_IIR));
 153         return IRQ_RETVAL(ret);
 154 }
 155
 156 #define DNV_DMA_CHAN_OFFSET 0x80
 157
 158 static int dnv_setup(struct mid8250 *mid, struct uart_port *p)
 159 {
 160         struct hsu_dma_chip *chip = &mid->dma_chip;
 161         struct pci_dev *pdev = to_pci_dev(p->dev);
 162         unsigned int bar = FL_GET_BASE(mid->board->flags);
 163         int ret;
 164
 165         pci_set_master(pdev);
 166
 167         ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
 168         if (ret < 0)
 169                 return ret;
 170
 171         p->irq = pci_irq_vector(pdev, 0);
 172
 173         chip->dev = &pdev->dev;
 174         chip->irq = pci_irq_vector(pdev, 0);
 175         chip->regs = p->membase;
 176         chip->length = pci_resource_len(pdev, bar);
 177         chip->offset = DNV_DMA_CHAN_OFFSET;
 178
 179         /* Falling back to PIO mode if DMA probing fails */
 180         ret = hsu_dma_probe(chip);
 181         if (ret)
 182                 return 0;
 183
 184         mid->dma_dev = pdev;
 185
 186         p->handle_irq = dnv_handle_irq;
 187         return 0;
 188 }
 189
 190 static void dnv_exit(struct mid8250 *mid)
 191 {
 192         if (!mid->dma_dev)
 193                 return;
 194         hsu_dma_remove(&mid->dma_chip);
 195 }
 196
 197 /*****************************************************************************/
 198
 199 static void mid8250_set_termios(struct uart_port *p,
 200                                 struct ktermios *termios,
 201                                 struct ktermios *old)
 202 {
 203         unsigned int baud = tty_termios_baud_rate(termios);
 204         struct mid8250 *mid = p->private_data;
 205         unsigned short ps = 16;
 206         unsigned long fuart = baud * ps;
 207         unsigned long w = BIT(24) - 1;
 208         unsigned long mul, div;
 209
 210         /* Gracefully handle the B0 case: fall back to B9600 */
 211         fuart = fuart ? fuart : 9600 * 16;
 212
 213         if (mid->board->freq < fuart) {
 214                 /* Find prescaler value that satisfies Fuart < Fref */
 215                 if (mid->board->freq > baud)
 216                         ps = mid->board->freq / baud;   /* baud rate too high */
 217                 else
 218                         ps = 1;                         /* PLL case */
 219                 fuart = baud * ps;
 220         } else {
 221                 /* Get Fuart closer to Fref */
 222                 fuart *= rounddown_pow_of_two(mid->board->freq / fuart);
 223         }
 224
 225         rational_best_approximation(fuart, mid->board->freq, w, w, &mul, &div);
 226         p->uartclk = fuart * 16 / ps;           /* core uses ps = 16 always */
 227
 228         writel(ps, p->membase + INTEL_MID_UART_PS);             /* set PS */
 229         writel(mul, p->membase + INTEL_MID_UART_MUL);           /* set MUL */
 230         writel(div, p->membase + INTEL_MID_UART_DIV);
 231
 232         serial8250_do_set_termios(p, termios, old);
 233 }
 234
 235 static bool mid8250_dma_filter(struct dma_chan *chan, void *param)
 236 {
 237         struct hsu_dma_slave *s = param;
 238
 239         if (s->dma_dev != chan->device->dev || s->chan_id != chan->chan_id)
 240                 return false;
 241
 242         chan->private = s;
 243         return true;
 244 }
 245
 246 static int mid8250_dma_setup(struct mid8250 *mid, struct uart_8250_port *port)
 247 {
 248         struct uart_8250_dma *dma = &mid->dma;
 249         struct device *dev = port->port.dev;
 250         struct hsu_dma_slave *rx_param;
 251         struct hsu_dma_slave *tx_param;
 252
 253         if (!mid->dma_dev)
 254                 return 0;
 255
 256         rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL);
 257         if (!rx_param)
 258                 return -ENOMEM;
 259
 260         tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL);
 261         if (!tx_param)
 262                 return -ENOMEM;
 263
 264         rx_param->chan_id = mid->dma_index * 2 + 1;
 265         tx_param->chan_id = mid->dma_index * 2;
 266
 267         dma->rxconf.src_maxburst = 64;
 268         dma->txconf.dst_maxburst = 64;
 269
 270         rx_param->dma_dev = &mid->dma_dev->dev;
 271         tx_param->dma_dev = &mid->dma_dev->dev;
 272
 273         dma->fn = mid8250_dma_filter;
 274         dma->rx_param = rx_param;
 275         dma->tx_param = tx_param;
 276
 277         port->dma = dma;
 278         return 0;
 279 }
 280
 281 static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 282 {
 283         struct uart_8250_port uart;
 284         struct mid8250 *mid;
 285         unsigned int bar;
 286         int ret;
 287
 288         ret = pcim_enable_device(pdev);
 289         if (ret)
 290                 return ret;
 291
 292         mid = devm_kzalloc(&pdev->dev, sizeof(*mid), GFP_KERNEL);
 293         if (!mid)
 294                 return -ENOMEM;
 295
 296         mid->board = (struct mid8250_board *)id->driver_data;
 297         bar = FL_GET_BASE(mid->board->flags);
 298
 299         memset(&uart, 0, sizeof(struct uart_8250_port));
 300
 301         uart.port.dev = &pdev->dev;
 302         uart.port.irq = pdev->irq;
 303         uart.port.private_data = mid;
 304         uart.port.type = PORT_16750;
 305         uart.port.iotype = UPIO_MEM;
 306         uart.port.uartclk = mid->board->base_baud * 16;
 307         uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 308         uart.port.set_termios = mid8250_set_termios;
 309
 310         uart.port.mapbase = pci_resource_start(pdev, bar);
 311         uart.port.membase = pcim_iomap(pdev, bar, 0);
 312         if (!uart.port.membase)
 313                 return -ENOMEM;
 314
 315         if (mid->board->setup) {
 316                 ret = mid->board->setup(mid, &uart.port);
 317                 if (ret)
 318                         return ret;
 319         }
 320
 321         ret = mid8250_dma_setup(mid, &uart);
 322         if (ret)
 323                 goto err;
 324
 325         ret = serial8250_register_8250_port(&uart);
 326         if (ret < 0)
 327                 goto err;
 328
 329         mid->line = ret;
 330
 331         pci_set_drvdata(pdev, mid);
 332         return 0;
 333 err:
 334         if (mid->board->exit)
 335                 mid->board->exit(mid);
 336         return ret;
 337 }
 338
 339 static void mid8250_remove(struct pci_dev *pdev)
 340 {
 341         struct mid8250 *mid = pci_get_drvdata(pdev);
 342
 343         serial8250_unregister_port(mid->line);
 344
 345         if (mid->board->exit)
 346                 mid->board->exit(mid);
 347 }
 348
 349 static const struct mid8250_board pnw_board = {
 350         .flags = FL_BASE0,
 351         .freq = 50000000,
 352         .base_baud = 115200,
 353         .setup = pnw_setup,
 354 };
 355
 356 static const struct mid8250_board tng_board = {
 357         .flags = FL_BASE0,
 358         .freq = 38400000,
 359         .base_baud = 1843200,
 360         .setup = tng_setup,
 361 };
 362
 363 static const struct mid8250_board dnv_board = {
 364         .flags = FL_BASE1,
 365         .freq = 133333333,
 366         .base_baud = 115200,
 367         .setup = dnv_setup,
 368         .exit = dnv_exit,
 369 };
 370
 371 #define MID_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }
 372
 373 static const struct pci_device_id pci_ids[] = {
 374         MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART1, pnw_board),
 375         MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART2, pnw_board),
 376         MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART3, pnw_board),
 377         MID_DEVICE(PCI_DEVICE_ID_INTEL_TNG_UART, tng_board),
 378         MID_DEVICE(PCI_DEVICE_ID_INTEL_CDF_UART, dnv_board),
 379         MID_DEVICE(PCI_DEVICE_ID_INTEL_DNV_UART, dnv_board),
 380         { },
 381 };
 382 MODULE_DEVICE_TABLE(pci, pci_ids);
 383
 384 static struct pci_driver mid8250_pci_driver = {
 385         .name           = "8250_mid",
 386         .id_table       = pci_ids,
 387         .probe          = mid8250_probe,
 388         .remove         = mid8250_remove,
 389 };
 390
 391 module_pci_driver(mid8250_pci_driver);
 392
 393 MODULE_AUTHOR("Intel Corporation");
 394 MODULE_LICENSE("GPL v2");
 395 MODULE_DESCRIPTION("Intel MID UART driver");