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/rational.h>
  13 #include <linux/module.h>
  14 #include <linux/pci.h>
  15
  16 #include <linux/dma/hsu.h>
  17 #include <linux/8250_pci.h>
  18
  19 #include "8250.h"
  20
  21 #define PCI_DEVICE_ID_INTEL_PNW_UART1   0x081b
  22 #define PCI_DEVICE_ID_INTEL_PNW_UART2   0x081c
  23 #define PCI_DEVICE_ID_INTEL_PNW_UART3   0x081d
  24 #define PCI_DEVICE_ID_INTEL_TNG_UART    0x1191
  25 #define PCI_DEVICE_ID_INTEL_DNV_UART    0x19d8
  26
  27 /* Intel MID Specific registers */
  28 #define INTEL_MID_UART_DNV_FISR         0x08
  29 #define INTEL_MID_UART_PS               0x30
  30 #define INTEL_MID_UART_MUL              0x34
  31 #define INTEL_MID_UART_DIV              0x38
  32
  33 struct mid8250;
  34
  35 struct mid8250_board {
  36         unsigned int flags;
  37         unsigned long freq;
  38         unsigned int base_baud;
  39         int (*setup)(struct mid8250 *, struct uart_port *p);
  40         void (*exit)(struct mid8250 *);
  41 };
  42
  43 struct mid8250 {
  44         int line;
  45         int dma_index;
  46         struct pci_dev *dma_dev;
  47         struct uart_8250_dma dma;
  48         struct mid8250_board *board;
  49         struct hsu_dma_chip dma_chip;
  50 };
  51
  52 /*****************************************************************************/
  53
  54 static int pnw_setup(struct mid8250 *mid, struct uart_port *p)
  55 {
  56         struct pci_dev *pdev = to_pci_dev(p->dev);
  57
  58         switch (pdev->device) {
  59         case PCI_DEVICE_ID_INTEL_PNW_UART1:
  60                 mid->dma_index = 0;
  61                 break;
  62         case PCI_DEVICE_ID_INTEL_PNW_UART2:
  63                 mid->dma_index = 1;
  64                 break;
  65         case PCI_DEVICE_ID_INTEL_PNW_UART3:
  66                 mid->dma_index = 2;
  67                 break;
  68         default:
  69                 return -EINVAL;
  70         }
  71
  72         mid->dma_dev = pci_get_slot(pdev->bus,
  73                                     PCI_DEVFN(PCI_SLOT(pdev->devfn), 3));
  74         return 0;
  75 }
  76
  77 static int tng_setup(struct mid8250 *mid, struct uart_port *p)
  78 {
  79         struct pci_dev *pdev = to_pci_dev(p->dev);
  80         int index = PCI_FUNC(pdev->devfn);
  81
  82         /* Currently no support for HSU port0 */
  83         if (index-- == 0)
  84                 return -ENODEV;
  85
  86         mid->dma_index = index;
  87         mid->dma_dev = pci_get_slot(pdev->bus, PCI_DEVFN(5, 0));
  88         return 0;
  89 }
  90
  91 static int dnv_handle_irq(struct uart_port *p)
  92 {
  93         struct mid8250 *mid = p->private_data;
  94         unsigned int fisr = serial_port_in(p, INTEL_MID_UART_DNV_FISR);
  95         int ret = IRQ_NONE;
  96
  97         if (fisr & BIT(2))
  98                 ret |= hsu_dma_irq(&mid->dma_chip, 1);
  99         if (fisr & BIT(1))
 100                 ret |= hsu_dma_irq(&mid->dma_chip, 0);
 101         if (fisr & BIT(0))
 102                 ret |= serial8250_handle_irq(p, serial_port_in(p, UART_IIR));
 103         return ret;
 104 }
 105
 106 #define DNV_DMA_CHAN_OFFSET 0x80
 107
 108 static int dnv_setup(struct mid8250 *mid, struct uart_port *p)
 109 {
 110         struct hsu_dma_chip *chip = &mid->dma_chip;
 111         struct pci_dev *pdev = to_pci_dev(p->dev);
 112         unsigned int bar = FL_GET_BASE(mid->board->flags);
 113         int ret;
 114
 115         chip->dev = &pdev->dev;
 116         chip->irq = pdev->irq;
 117         chip->regs = p->membase;
 118         chip->length = pci_resource_len(pdev, bar);
 119         chip->offset = DNV_DMA_CHAN_OFFSET;
 120
 121         /* Falling back to PIO mode if DMA probing fails */
 122         ret = hsu_dma_probe(chip);
 123         if (ret)
 124                 return 0;
 125
 126         mid->dma_dev = pdev;
 127
 128         p->handle_irq = dnv_handle_irq;
 129         return 0;
 130 }
 131
 132 static void dnv_exit(struct mid8250 *mid)
 133 {
 134         if (!mid->dma_dev)
 135                 return;
 136         hsu_dma_remove(&mid->dma_chip);
 137 }
 138
 139 /*****************************************************************************/
 140
 141 static void mid8250_set_termios(struct uart_port *p,
 142                                 struct ktermios *termios,
 143                                 struct ktermios *old)
 144 {
 145         unsigned int baud = tty_termios_baud_rate(termios);
 146         struct mid8250 *mid = p->private_data;
 147         unsigned short ps = 16;
 148         unsigned long fuart = baud * ps;
 149         unsigned long w = BIT(24) - 1;
 150         unsigned long mul, div;
 151
 152         if (mid->board->freq < fuart) {
 153                 /* Find prescaler value that satisfies Fuart < Fref */
 154                 if (mid->board->freq > baud)
 155                         ps = mid->board->freq / baud;   /* baud rate too high */
 156                 else
 157                         ps = 1;                         /* PLL case */
 158                 fuart = baud * ps;
 159         } else {
 160                 /* Get Fuart closer to Fref */
 161                 fuart *= rounddown_pow_of_two(mid->board->freq / fuart);
 162         }
 163
 164         rational_best_approximation(fuart, mid->board->freq, w, w, &mul, &div);
 165         p->uartclk = fuart * 16 / ps;           /* core uses ps = 16 always */
 166
 167         writel(ps, p->membase + INTEL_MID_UART_PS);             /* set PS */
 168         writel(mul, p->membase + INTEL_MID_UART_MUL);           /* set MUL */
 169         writel(div, p->membase + INTEL_MID_UART_DIV);
 170
 171         serial8250_do_set_termios(p, termios, old);
 172 }
 173
 174 static bool mid8250_dma_filter(struct dma_chan *chan, void *param)
 175 {
 176         struct hsu_dma_slave *s = param;
 177
 178         if (s->dma_dev != chan->device->dev || s->chan_id != chan->chan_id)
 179                 return false;
 180
 181         chan->private = s;
 182         return true;
 183 }
 184
 185 static int mid8250_dma_setup(struct mid8250 *mid, struct uart_8250_port *port)
 186 {
 187         struct uart_8250_dma *dma = &mid->dma;
 188         struct device *dev = port->port.dev;
 189         struct hsu_dma_slave *rx_param;
 190         struct hsu_dma_slave *tx_param;
 191
 192         if (!mid->dma_dev)
 193                 return 0;
 194
 195         rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL);
 196         if (!rx_param)
 197                 return -ENOMEM;
 198
 199         tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL);
 200         if (!tx_param)
 201                 return -ENOMEM;
 202
 203         rx_param->chan_id = mid->dma_index * 2 + 1;
 204         tx_param->chan_id = mid->dma_index * 2;
 205
 206         dma->rxconf.src_maxburst = 64;
 207         dma->txconf.dst_maxburst = 64;
 208
 209         rx_param->dma_dev = &mid->dma_dev->dev;
 210         tx_param->dma_dev = &mid->dma_dev->dev;
 211
 212         dma->fn = mid8250_dma_filter;
 213         dma->rx_param = rx_param;
 214         dma->tx_param = tx_param;
 215
 216         port->dma = dma;
 217         return 0;
 218 }
 219
 220 static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 221 {
 222         struct uart_8250_port uart;
 223         struct mid8250 *mid;
 224         unsigned int bar;
 225         int ret;
 226
 227         ret = pcim_enable_device(pdev);
 228         if (ret)
 229                 return ret;
 230
 231         pci_set_master(pdev);
 232
 233         mid = devm_kzalloc(&pdev->dev, sizeof(*mid), GFP_KERNEL);
 234         if (!mid)
 235                 return -ENOMEM;
 236
 237         mid->board = (struct mid8250_board *)id->driver_data;
 238         bar = FL_GET_BASE(mid->board->flags);
 239
 240         memset(&uart, 0, sizeof(struct uart_8250_port));
 241
 242         uart.port.dev = &pdev->dev;
 243         uart.port.irq = pdev->irq;
 244         uart.port.private_data = mid;
 245         uart.port.type = PORT_16750;
 246         uart.port.iotype = UPIO_MEM;
 247         uart.port.uartclk = mid->board->base_baud * 16;
 248         uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 249         uart.port.set_termios = mid8250_set_termios;
 250
 251         uart.port.mapbase = pci_resource_start(pdev, bar);
 252         uart.port.membase = pcim_iomap(pdev, bar, 0);
 253         if (!uart.port.membase)
 254                 return -ENOMEM;
 255
 256         if (mid->board->setup) {
 257                 ret = mid->board->setup(mid, &uart.port);
 258                 if (ret)
 259                         return ret;
 260         }
 261
 262         ret = mid8250_dma_setup(mid, &uart);
 263         if (ret)
 264                 goto err;
 265
 266         ret = serial8250_register_8250_port(&uart);
 267         if (ret < 0)
 268                 goto err;
 269
 270         mid->line = ret;
 271
 272         pci_set_drvdata(pdev, mid);
 273         return 0;
 274 err:
 275         if (mid->board->exit)
 276                 mid->board->exit(mid);
 277         return ret;
 278 }
 279
 280 static void mid8250_remove(struct pci_dev *pdev)
 281 {
 282         struct mid8250 *mid = pci_get_drvdata(pdev);
 283
 284         if (mid->board->exit)
 285                 mid->board->exit(mid);
 286
 287         serial8250_unregister_port(mid->line);
 288 }
 289
 290 static const struct mid8250_board pnw_board = {
 291         .flags = FL_BASE0,
 292         .freq = 50000000,
 293         .base_baud = 115200,
 294         .setup = pnw_setup,
 295 };
 296
 297 static const struct mid8250_board tng_board = {
 298         .flags = FL_BASE0,
 299         .freq = 38400000,
 300         .base_baud = 1843200,
 301         .setup = tng_setup,
 302 };
 303
 304 static const struct mid8250_board dnv_board = {
 305         .flags = FL_BASE1,
 306         .freq = 133333333,
 307         .base_baud = 115200,
 308         .setup = dnv_setup,
 309         .exit = dnv_exit,
 310 };
 311
 312 #define MID_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }
 313
 314 static const struct pci_device_id pci_ids[] = {
 315         MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART1, pnw_board),
 316         MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART2, pnw_board),
 317         MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART3, pnw_board),
 318         MID_DEVICE(PCI_DEVICE_ID_INTEL_TNG_UART, tng_board),
 319         MID_DEVICE(PCI_DEVICE_ID_INTEL_DNV_UART, dnv_board),
 320         { },
 321 };
 322 MODULE_DEVICE_TABLE(pci, pci_ids);
 323
 324 static struct pci_driver mid8250_pci_driver = {
 325         .name           = "8250_mid",
 326         .id_table       = pci_ids,
 327         .probe          = mid8250_probe,
 328         .remove         = mid8250_remove,
 329 };
 330
 331 module_pci_driver(mid8250_pci_driver);
 332
 333 MODULE_AUTHOR("Intel Corporation");
 334 MODULE_LICENSE("GPL v2");
 335 MODULE_DESCRIPTION("Intel MID UART driver");