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

   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");