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         unsigned int fisr = serial_port_in(p, INTEL_MID_UART_DNV_FISR);
 100         int ret = IRQ_NONE;
 101
 102         if (fisr & BIT(2))
 103                 ret |= hsu_dma_irq(&mid->dma_chip, 1);
 104         if (fisr & BIT(1))
 105                 ret |= hsu_dma_irq(&mid->dma_chip, 0);
 106         if (fisr & BIT(0))
 107                 ret |= serial8250_handle_irq(p, serial_port_in(p, UART_IIR));
 108         return ret;
 109 }
 110
 111 #define DNV_DMA_CHAN_OFFSET 0x80
 112
 113 static int dnv_setup(struct mid8250 *mid, struct uart_port *p)
 114 {
 115         struct hsu_dma_chip *chip = &mid->dma_chip;
 116         struct pci_dev *pdev = to_pci_dev(p->dev);
 117         unsigned int bar = FL_GET_BASE(mid->board->flags);
 118         int ret;
 119
 120         chip->dev = &pdev->dev;
 121         chip->irq = pdev->irq;
 122         chip->regs = p->membase;
 123         chip->length = pci_resource_len(pdev, bar);
 124         chip->offset = DNV_DMA_CHAN_OFFSET;
 125
 126         /* Falling back to PIO mode if DMA probing fails */
 127         ret = hsu_dma_probe(chip);
 128         if (ret)
 129                 return 0;
 130
 131         mid->dma_dev = pdev;
 132
 133         p->handle_irq = dnv_handle_irq;
 134         return 0;
 135 }
 136
 137 static void dnv_exit(struct mid8250 *mid)
 138 {
 139         if (!mid->dma_dev)
 140                 return;
 141         hsu_dma_remove(&mid->dma_chip);
 142 }
 143
 144 /*****************************************************************************/
 145
 146 static void mid8250_set_termios(struct uart_port *p,
 147                                 struct ktermios *termios,
 148                                 struct ktermios *old)
 149 {
 150         unsigned int baud = tty_termios_baud_rate(termios);
 151         struct mid8250 *mid = p->private_data;
 152         unsigned short ps = 16;
 153         unsigned long fuart = baud * ps;
 154         unsigned long w = BIT(24) - 1;
 155         unsigned long mul, div;
 156
 157         if (mid->board->freq < fuart) {
 158                 /* Find prescaler value that satisfies Fuart < Fref */
 159                 if (mid->board->freq > baud)
 160                         ps = mid->board->freq / baud;   /* baud rate too high */
 161                 else
 162                         ps = 1;                         /* PLL case */
 163                 fuart = baud * ps;
 164         } else {
 165                 /* Get Fuart closer to Fref */
 166                 fuart *= rounddown_pow_of_two(mid->board->freq / fuart);
 167         }
 168
 169         rational_best_approximation(fuart, mid->board->freq, w, w, &mul, &div);
 170         p->uartclk = fuart * 16 / ps;           /* core uses ps = 16 always */
 171
 172         writel(ps, p->membase + INTEL_MID_UART_PS);             /* set PS */
 173         writel(mul, p->membase + INTEL_MID_UART_MUL);           /* set MUL */
 174         writel(div, p->membase + INTEL_MID_UART_DIV);
 175
 176         serial8250_do_set_termios(p, termios, old);
 177 }
 178
 179 static bool mid8250_dma_filter(struct dma_chan *chan, void *param)
 180 {
 181         struct hsu_dma_slave *s = param;
 182
 183         if (s->dma_dev != chan->device->dev || s->chan_id != chan->chan_id)
 184                 return false;
 185
 186         chan->private = s;
 187         return true;
 188 }
 189
 190 static int mid8250_dma_setup(struct mid8250 *mid, struct uart_8250_port *port)
 191 {
 192         struct uart_8250_dma *dma = &mid->dma;
 193         struct device *dev = port->port.dev;
 194         struct hsu_dma_slave *rx_param;
 195         struct hsu_dma_slave *tx_param;
 196
 197         if (!mid->dma_dev)
 198                 return 0;
 199
 200         rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL);
 201         if (!rx_param)
 202                 return -ENOMEM;
 203
 204         tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL);
 205         if (!tx_param)
 206                 return -ENOMEM;
 207
 208         rx_param->chan_id = mid->dma_index * 2 + 1;
 209         tx_param->chan_id = mid->dma_index * 2;
 210
 211         dma->rxconf.src_maxburst = 64;
 212         dma->txconf.dst_maxburst = 64;
 213
 214         rx_param->dma_dev = &mid->dma_dev->dev;
 215         tx_param->dma_dev = &mid->dma_dev->dev;
 216
 217         dma->fn = mid8250_dma_filter;
 218         dma->rx_param = rx_param;
 219         dma->tx_param = tx_param;
 220
 221         port->dma = dma;
 222         return 0;
 223 }
 224
 225 static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 226 {
 227         struct uart_8250_port uart;
 228         struct mid8250 *mid;
 229         unsigned int bar;
 230         int ret;
 231
 232         ret = pcim_enable_device(pdev);
 233         if (ret)
 234                 return ret;
 235
 236         pci_set_master(pdev);
 237
 238         mid = devm_kzalloc(&pdev->dev, sizeof(*mid), GFP_KERNEL);
 239         if (!mid)
 240                 return -ENOMEM;
 241
 242         mid->board = (struct mid8250_board *)id->driver_data;
 243         bar = FL_GET_BASE(mid->board->flags);
 244
 245         memset(&uart, 0, sizeof(struct uart_8250_port));
 246
 247         uart.port.dev = &pdev->dev;
 248         uart.port.irq = pdev->irq;
 249         uart.port.private_data = mid;
 250         uart.port.type = PORT_16750;
 251         uart.port.iotype = UPIO_MEM;
 252         uart.port.uartclk = mid->board->base_baud * 16;
 253         uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 254         uart.port.set_termios = mid8250_set_termios;
 255
 256         uart.port.mapbase = pci_resource_start(pdev, bar);
 257         uart.port.membase = pcim_iomap(pdev, bar, 0);
 258         if (!uart.port.membase)
 259                 return -ENOMEM;
 260
 261         if (mid->board->setup) {
 262                 ret = mid->board->setup(mid, &uart.port);
 263                 if (ret)
 264                         return ret;
 265         }
 266
 267         ret = mid8250_dma_setup(mid, &uart);
 268         if (ret)
 269                 goto err;
 270
 271         ret = serial8250_register_8250_port(&uart);
 272         if (ret < 0)
 273                 goto err;
 274
 275         mid->line = ret;
 276
 277         pci_set_drvdata(pdev, mid);
 278         return 0;
 279 err:
 280         if (mid->board->exit)
 281                 mid->board->exit(mid);
 282         return ret;
 283 }
 284
 285 static void mid8250_remove(struct pci_dev *pdev)
 286 {
 287         struct mid8250 *mid = pci_get_drvdata(pdev);
 288
 289         if (mid->board->exit)
 290                 mid->board->exit(mid);
 291
 292         serial8250_unregister_port(mid->line);
 293 }
 294
 295 static const struct mid8250_board pnw_board = {
 296         .flags = FL_BASE0,
 297         .freq = 50000000,
 298         .base_baud = 115200,
 299         .setup = pnw_setup,
 300 };
 301
 302 static const struct mid8250_board tng_board = {
 303         .flags = FL_BASE0,
 304         .freq = 38400000,
 305         .base_baud = 1843200,
 306         .setup = tng_setup,
 307 };
 308
 309 static const struct mid8250_board dnv_board = {
 310         .flags = FL_BASE1,
 311         .freq = 133333333,
 312         .base_baud = 115200,
 313         .setup = dnv_setup,
 314         .exit = dnv_exit,
 315 };
 316
 317 #define MID_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }
 318
 319 static const struct pci_device_id pci_ids[] = {
 320         MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART1, pnw_board),
 321         MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART2, pnw_board),
 322         MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART3, pnw_board),
 323         MID_DEVICE(PCI_DEVICE_ID_INTEL_TNG_UART, tng_board),
 324         MID_DEVICE(PCI_DEVICE_ID_INTEL_DNV_UART, dnv_board),
 325         { },
 326 };
 327 MODULE_DEVICE_TABLE(pci, pci_ids);
 328
 329 static struct pci_driver mid8250_pci_driver = {
 330         .name           = "8250_mid",
 331         .id_table       = pci_ids,
 332         .probe          = mid8250_probe,
 333         .remove         = mid8250_remove,
 334 };
 335
 336 module_pci_driver(mid8250_pci_driver);
 337
 338 MODULE_AUTHOR("Intel Corporation");
 339 MODULE_LICENSE("GPL v2");
 340 MODULE_DESCRIPTION("Intel MID UART driver");